taxonomic approach to the study of medicinal plants and animal-derived drugs

Chapter 5 A taxonomic approach to the study of medicinal plants and animal-derived drugs



THALLOPHYTES 18
BACTERIA AND ALGAE 18

FUNGI 19

LICHENS 21

BRYOPHYTES AND PTERIDOPHYTES 21
BRYOPHYTA 21

PTERIDOPHYTA 21

GYMNOSPERMS 22

ANGIOSPERMS: DICOTYLEDONS 23
SUBCLASS ARCHICHLAMYDEAE 24

SUBCLASS SYMPETALAE 34

ANGIOSPERMS: MONOCOTYLEDONS 40

ANIMAL PRODUCTS 42

For classification purposes the plant and animal kingdoms are each divided into a number of phyla and in addition to the phyla, the classification includes groupings of gradually diminishing size, namely divisions, classes, orders, suborders and families. According to the system used, these groupings may, or may not, indicate phylogenetic relationships.


In this chapter the principal plant families of pharmaceutical interest are arranged according to the botanical scheme of Engler (q.v.). The chapter is divided into six parts: Thallophytes; Bryophytes and Pteridophytes; Gymnosperms; Angiosperms (Dicotyledons); Angiosperms (Monocotyledons); Animal Products. At the beginning of each large taxon of plants a table is given to clarify the orders and families involved. Following the listed genera for each family, notes on the uses and constituents of specific plants not included in Part 5 are given. According to the botanical system of classification considered, schemes vary, as do the numbers of families, genera and species cited within an order.



THALLOPHYTES


The old term ‘thallophyte’ includes those plants which are not differentiated into root, stem and leaves. Engler divides them into 13 phyla. They include bacteria, algae, fungi and lichens. The positions of the main families of pharmaceutical interest are indicated below.


































Phyla Orders Families
Bacteriophyta Eubacteriales Rhizobiaceae, Micrococcaceae
Chrysophyta Discales Actinodiscaceae
(Diatomeae) Pennatales Fragilariaceae, Naviculariaceae
Phaeophyta (Brown Algae) Laminariales Laminariaceae
Fucales Fucaceae, Sargassaceae
Rhodophyta (Red Algae) Gelidiales Gelidiaceae
Gigartinales Gracilariaceae, Gigartinaceae


BACTERIA AND ALGAE



BACTERIOPHYTA


The bacteria are unicellular organisms, the great majority of which range in size from 0.75 to 8 mu;m. They reproduce by binary fission. Most species of bacteria contain no chlorophyll, although there is one group whose members contain a chlorophyll-like pigment and photosynthesize. Recent research has revealed much more of the details of cellular structure and it has been possible to distinguish in certain species, in no small detail, the various components of the cell. For example, in Escherichia coli the cell wall consists of a four-layer structure, the inner one being rigid, the three outer ones non-rigid. Within the three-layer wall structure lies a protoplast membrane enclosing the cytoplasm. The protoplast membrane acts as a permeability barrier to all but very large molecules and contains enzymes concerned with respiration and the active transport of metabolities.


Bacteria exist in a number of characteristic shapes, namely:


1 Rod-shaped or bacillary forms (e.g. Clostridium welchii, Escherichia coli and Bacillus subtilis).

2 Spherical or coccal forms, which can occur singly but are usually found in characteristic aggregates—i.e. in chains (streptococci), in groups of two (diplococci), four (tetracocci) or eight (sarcinae). Aggregates of irregular pattern are said to be of staphylococcal form.

3 Twisted or spirillar forms which, if having a single twist, belong to the genus Vibrio, while those with more than one twist belong to the genus Spirillum.

4 Branched forms which sometimes occur in the genus Mycobacterium.

Other important morphological features which are of value in classifying bacteria are: (1) The possession of flagella, thread-like processes whose number and position are often of diagnostic importance. (2) The formation of capsules consisting of polysaccharide material which is of great importance in relation to the immunological properties of the organism. (3) The possession of endospores, which are highly refractive bodies formed by certain species under what appear to be adverse environmental conditions. The position of the spore in relation to the rest of the cell is of diagnostic importance. (4) Pigmentation; many bacteria are capable of elaborating complex colouring matters.


Bacteria are able to carry out a very wide range of chemical reactions, some of which are used for identification and differentiation, in addition to forming the basis of many important industrial processes. Bacterial action is used, for example, in the production of vinegar, acetone, butyl alcohol, lactic acid and L-sorbose. Notable examples of reactions which are useful for characterizing bacteria are the ability to ferment carbohydrates with the formation of acidic and gaseous products; the ability to digest protein, as shown by gelatin liquefaction; the production of hydrogen sulphide from organic sulphur compounds.


Bacteria are most important in medicine and pharmacy in the following respects: as disease-producing organisms (about 10% of bacteria are probably pathogenic); for producing antibiotics (Chapter 30); for effecting biochemical conversions; as agents in the deterioration of crude drugs and medicaments (Chapter 15); the production of transformed root cultures and transgenic medicinal plants by Agrobacterium spp. (Chapters 11 and 12); in genetic engineering involving recombinant DNA (e.g. the production of human insulin). Bacteria also play a vital role in nature—for example, in the nitrogen cycle atmospheric nitrogen is fixed by Azotobacter or, symbiotically, by various species of Rhizobium. Nitrosomonas is able to oxidize ammonia to nitrite, while Nitrobacter can oxidize nitrite to nitrate. Bacteria are important in sewage purification, in the retting of fibres such as jute and flax, and in the ripening of cheese.



CHRYSOPHYTA: DISCALES



Actinodiscaceae


The Chrysophyta has three classes, one of which is the Bacillariophyceae (Diatomeae), containing some 10 000 species of diatom. They are unicellular algae, have a silica skeleton, and show infinite variety in shape and in the sculpturing of the cell wall. There are two main types: the subclass Centricae (in which Discales is one of the orders) and subclass Pennatae (which includes the order Pennatales). The Centricae are centric or discoid in shape and generally marine, while the Pennatae are pennate or naviculoid and more often occur in fresh water.


An example of the family Actinodiscaceae is Arachnoidiscus, found in Japanese agar (q.v.) and other genera are found in the fossil deposits of diatomite or kieselguhr (q.v.).



CHRYSOPHYTA: PENNATALES



Fragilariaceae and Naviculariaceae


Species of these two families occur in diatomite and are illustrated in Fig. 34.1.



PHAEOPHYTA: LAMINARIALES



Laminariaceae


The brown algae are mainly marine and vary from microscopic branched filaments to leathery frond-like forms up to 60 m in length. They owe their brown colour to the carotenoid pigment fucoxanthin, which masks the other pigments.


Many of the 30 species of Laminaria are used in coastal districts for agricultural purposes. They are used for the manufacture of alginic acid (q.v.), mannitol and iodine.



PHAEOPHYTA: FUCALES



Fucaceae and Sargassaceae


Examples of the Fucaceae are Fucus (about 30 spp.) and Pelvetia; and of the Sargassaceae about 250 species of Sargassum. These are collected on a large scale in many parts of the world for the production of alginic acid and its derivatives. The species have been much investigated for biologically active properties; F. vesiculosus, for example, gives water-soluble extracts that inhibit the activity of the HIV reverse-transcriptase enzyme.



RHODOPHYTA: GELIDIALES



Gelidiaceae


The red algae are divided into 11 orders. The 3000 species are mainly marine and are particularly abundant in the tropics and subtropics. Most are relatively small. Their plastids contain chlorophyll, the red pigment phycoerythrin (usually in sufficient quantity to mask the other pigments), and sometimes the blue pigment phycocyanin.


Important genera of the Gelidiaceae are Gelidium (about 40 spp.) and Pterocladia (5 spp.). Many of these are used in the preparation of agars (q.v.).



RHODOPHYTA: GIGARTINALES



Gracilariaceae and Gigartinaceae


Gracilaria (100 spp.) is a source of agar, particularly G. lichenoides, found in the Indian Ocean. In the Gigartinaceae Chondrus crispus yields carageen or Irish moss (q.v.); Gigartina stellata has been investigated as a source of British agar.



FUNGI


The fungi are saprophytic or parasitic members of the Thallophyta, entirely devoid of chlorophyll. The plant body is made up of filaments or hyphae, which together constitute the mycelium. The hyphae may be aseptate and coenocytic, but are often septate, the individual segments being uni-, bi- or multinucleate. In the formation of fruiting bodies the hyphae may become woven into dense masses of pseudoparenchyma (e.g. the sclerotium of ergot).


The protoplast of fungal cells consists of granular or reticulate cytoplasm, which in older cells is often vacuolated. The nucleus may show a delicate reticulum and one or more nucleoli or its contents may be condensed into a chromatin body. The cell wall in many Archimycetes and some Phycomycetes (Oomycetes) and in the yeasts consists mainly of cellulose, but in other fungi cellulose is replaced by the nitrogenous substance chitin.


Sexual and asexual reproduction occur. The characteristic spores of the sporophyte generation are known as oospores (produced endogenously) or basidiospores (produced exogenously). In the Fungi Imperfecti the sporophyte generation is missing. The fungi also produce spores having no significance in the alternation of the generations; they are borne on the gametophyte (Phycomycetes and Ascomycetes) or on the sporophyte (rusts and some Autobasidiomycetes). These accessory spores often take the form of conidia, non-motile spores, borne externally on conidiophores.


The Archimycetes are the simplest fungi, in which the mycelium is absent or rudimentary. A member of this group causes wart disease in potatoes. The following groups and families are of pharmaceutical interest.











































Class Order Families
Phycomycetes Mucorales Mucoraceae
Ascomycetes Protoascales Saccharomycetaceae
Plectascales Aspergillaceae
Sphaeriales Hypocreaceae
Clavicipitales Clavicipitaceae
Basidiomycetes Polyporinales Polyporaceae
Agaricales Tricholometaceae
Amanitaceae
Agaricaceae
Phallinales Phallinaceae
Fungi Imperfecti Moniliales Dematiaceae


PHYCOMYCETES: MUCORALES



Mucoraceae


These fungi have an aseptate mycelium; members include Phytophthora infestans, which causes potato blight. In the Mucoraceae we have Mucor (40 spp.) and Rhizopus (8 spp.), which are among the moulds associated with badly stored food products. Some Rhizopus species are used industrially for the saccharification of starchy material and for producing D-lactic acid from glucose; they are important in the microbiological conversions of steroids (q.v.).



ASCOMYCETES: PROTOASCALES



Saccharomycetaceae


This group includes the yeasts, some 30 species of Saccharomyces. Dried yeast (q.v.) is prepared from a strain of S. cerevisiae. A member of the related family Cryptococcaceae is Candida utilis, which produces torula yeast, a rich source of proteins and vitamins.



PLECTASCALES



Aspergillaceae


In this order the conidial stage is more prominent than the ascal stage. Penicillium (over 100 spp.) yields important antibiotics (q.v.) such as penicillin and griseofulvin; also the immunosuppressant mycophenolic acid. P. islandicum forms emodin. Among the 60 species of Aspergillus may be noted A. oryzae, used in the manufacture of soya sauce; A. fumigatus, producing the antibiotic fumagillin; and A. flavus producing aflatoxin in poorly stored feeding materials.



SPHAERIALES



Hypocreaceae


Gibberella (10 spp.) produces the plant growth regulators known as gibberellins, first isolated from G. fugikuroi, see Chapter 12.



CLAVICIPITALES



Clavicipitaceae


Like other Ascomycetes, the ascospores are produced in a sac or ascus. Claviceps (10 spp.) includes ergot, the sclerotium of C. purpurea; Cordyceps (100 spp.) includes C. sinensis, one of the most valued species in Chinese traditional medicine but limited in use by a shortage of supply. C. militaris has similar properties and efforts are devoted to its artificial culture; R. Yu et al., have purified and identified four polysaccharides from cultured material (Fitoterapia, 2004, 75, 662).



BASIDIOMYCETES: POLYPORINALES


The Basidiomycetes produce basidiospores, borne externally on the spore mothercell or basidium. They have septate mycelia which produce elaborate fruiting bodies (e.g. mushrooms). Some members are edible, others poisonous.



Polyporaceae


The Polyporaceae includes Polyporus, Polystichus, Fomes, Ganoderma and Boletus (200 spp.). Polyporus officinalis (white agaric) and P. fomentarius were formerly used in medicine. Ganoderma lucida has long been used in Chinese medicine and its biologically active triterpenoids have attracted attention. Boletus edulis is edible.



AGARICALES


An order of several families.



Tricholometaceae


The Tricholometaceae contains Clitocybe (80 spp.), species of which produce muscarine (q.v.). Other families of the order contain Stropharia, Psilocybe and Conocybe, which produce hallucinogenic substances (q.v.) such as psilosin and psilocybin.



Amanitaceae


The family includes Amanita (50–60 spp.) and Pluteus; Amanita muscaria (fly agaric) and A. pantherina contain muscarine (q.v.).



Agaricaceae


This family includes the common mushroom, Agaricus campestris. The genus Agaricus (Psalliota) contains about 30 species.



PHALLINALES


The order contains two families.



Phallinaceae


The Phallinaceae takes its name from Phallus (10 spp.). Phallus impudicus is the stinkhorn.



FUNGI IMPERFECTI: MONILIALES


The Fungi Imperfecti is a group in which sexual spores have not been demonstrated. Some members may be Ascomycetes which have completely lost the ascus stage.



Dematiaceae


The family Dematiaceae contains Helminthosporium (150–200 spp.), a species of which, H. graminium, produces helminthosporin (q.v.). Another family of the group, the Tuberculariaceae, contains Fusarium (65 spp.). Fusarium lini will transform digitoxigenin into digoxigenin.


Fungal spores are a common source of allergens.



LICHENS


A lichen is a symbiotic association of an alga and a fungal partner. Some, particularly in arctic regions, are used as food. The desert species Lecanora esculenta is regarded as the biblical manna. The ‘oak moss’ used as a fixative in perfumery is the lichen Evernia prunastri. Many lichens contain derivatives of orcinol, orcellic acid and lecanoric acid; these compounds are termed depsides and are phenolic acids formed by the interaction of the carboxyl group of one molecule with the hydroxyl group of another. A class of these acids termed depsidones (e.g. norstictic and psoromic acids) complex with metals and are probably responsible for the ability of lichens to flourish on mineral-rich soils including mine tailings and to accumulate large quantities of metals, such as copper, zinc etc.


Lichen dyes were formerly much used in the textile industry. Litmus, produced from certain lichens (e.g. Lecanora, Roccella spp.) by fermentation, is used as an indicator.


Iceland moss, Cetraria islandica, has been used for disguising the taste of nauseous medicines and with other species (e.g. Cladonia spp.) for the treatment of cough. It contains the very bitter depsidone, cetraric acid. Many lichens have antibiotic properties as illustrated by usnic acid, found in Cladonia and Usnea spp. (see E. R. Correché et al. 1998, Fitoterapia, 69, 493; V. Marcano et al., J. Ethnopharmacology, 1999, 66, 343); 29 species of Icelandic lichens have recently been investigated for their cancer chemopreventive and cytotoxic activity (K. Ingólfsdóttir et al., Pharm. Biol., 2000, 38, 313).


It is possible to isolate and grow the algae from lichens as suspension cultures (see P. Härmälä et al., Fitoterapia, 1992, 63, 217).


The accompanying list indicates some of the families and genera of recent interest.






































Order Family Genera
Roccellales Roccellaceae Roccella (31 spp.)
Lecanorales Pertusariaceae Pertusaria (608 spp.)
Lecanoraceae Lecanora (1100 spp.)
Parmeliaceae Parmelia (800 spp.)
Cetraria (62 spp.)
Usneaceae Usnea (500 spp.)
Evernia (8 spp.)
Alectoria (48 spp.)
Caloplacales Caloplacaceae Caloplaca (480 spp.)
Teloschistaceae Xanthoria (21 spp.)


BRYOPHYTES AND PTERIDOPHYTES


These two phyla are of relatively small pharmaceutical importance, but have some phytochemical interest.



BRYOPHYTA


The phylum is divided into two classes, Hepaticae (liverworts) and Musci (mosses). Both show alternation of generations. The more conspicuous gametophyte generation is a leaf-like thallus in the liverworts and a leafy plant with a stem in the mosses. On the latter is borne the sporophyte generation with sporangium.


Of the many bryophyte orders, families and genera, a few which have been subjects of recent research are listed below.





























Class Order Genera
Hepaticae Jungermaniinales Bazzania, Solenostoma,
Gymnomitrion,
Diplophyllum
Jubulineales Lunularia
Musci Sphagnales Sphagnum (336 spp.)
Dicranales Dicranum (52 spp.)
Funariales Funaria (117 spp.)

Peat, long used as a domestic fuel, consists of partly decayed mosses and other plants. In some areas (e.g. parts of Ireland) deposits of bog moss (largely species of Sphagnum) are many feet thick, and after the surface has been skimmed off, soil may be excavated in a very pure form. Sphagnum moss, consisting of a mixture of various species of Sphagnum, can be collected in many parts of Britain. It may be used (enclosed in muslin bags) as an absorbent dressing or compressed into sheets, making absorbent mattresses. Large quantities were used in this way in World War I.


The pharmacologically active terpenoids (sesquiterpenes, diterpenes) and aromatic compounds of the bryophytes have been well studied. (For a review see Y. Asakawa, Proc. Phytochem. Soc. Eur., 1990, 29, 369. This volume (eds. H. D. Zinsmeister and R. Mues), published by Clarendon Press, Oxford, also includes a further 28 review articles covering the chemistry and chemical taxonomy of the Bryophytes.)



PTERIDOPHYTA


The Pteridophyta includes the Filices (ferns), Articulatae (horsetails) and Lycopsida (club mosses). They show an alternation of generations, the sporophyte being the larger. A few are of medical importance.


Of the many families, subfamilies and genera the following may be noted.



image

Male fern rhizome (q.v.) derived from Dryopteris filix-mas is one of many ferns containing phloroglucinol derivatives. The insect-moulding hormones or pterosins are widely distributed in ferns and attract considerable research.


Various species of Adiantum (the maiden hair ferns) are recorded as used in traditional medicine in Europe, Saudi Arabia, Africa and the Indian subcontinent. They contain hopane triterpenoids, a group of squalane-derived compounds more commonly associated with bacterial membranes. G. Brahmachari and D. Chatterjee record the isolation of a new one-such constituent from A. lunulactum (syn. A. philippense) (Fitoterapia, 2002, 73, 363).


The dried sterile stems of the horsetail, Equisetum arvense are used in herbal medicine and are listed in the BHP (1996) and the BP/EP. There are apparently two chemotypes of the species with different flavonoid compositions. Horsetails give a high mineral ash containing considerable amounts of silica. Correct identification of the herb is important because the related species E. palustre is poisonous.


The spores of lycopodium (Lycopodium clavatum) are used in quantitative microscopy (q.v.) and to a limited extent in medicated snuffs, dusting powders and lubricants. As a dusting powder for rubber gloves it has been known to give rise to dermatitis and mild caution has been expressed regarding its use as a lubricant non-stick agent for condoms relative to a possible cause of granulomas. The lycopodium alkaloids have been extensively studied (for a review see W. A. Ayer and L. S. Trifonov, Alkaloids, 1994, 45, 233). Huperzia serrata (a club moss), now assigned to Lycopodium, contains the unusual alkaloid huperzine A and has been long-used in Chinese medicine for the treatment Alzheimer’s and related conditions (see also Chapter 8).


Bracken (Pteridium aquilinum) has been a recent cause of concern owing to its carcinogenic properties and known bovine poisoning. The use of the young shoots for culinary purposes is discouraged and avoidance of bracken spores in the atmosphere suggested. The toxic constituent is ptaquiloside, an unstable glycoside of an illudane-type norsesquiterpene. Other similar compounds are widely distributed in the genus Pteridium.



GYMNOSPERMS


The division Gymnospermae contains many fossil members. Of the 11 orders in the Engler classification, it is only necessary to mention five orders and 10 families:






























Orders Families
Cycadales Cycadaceae
Ginkgoales Ginkgoaceae
Coniferae Pinaceae, Taxodiaceae,
Cupressaceae,
Araucariaceae,
Podocarpaceae,
Cephalotaxaceae
Taxales Taxaceae
Gnetales Ephedraceae

The gymnosperms are one of the two great divisions of the seed-bearing plants or spermaphyta. They differ from the angiosperms in having ovules which are not enclosed in an ovary. A perianth is absent except in the Gnetales. The seeds usually contain one mature embryo with from two to 15 cotyledons embedded in endosperm. The wood is composed largely of tracheids, vessels being absent.



CYCADALES



Cycadaceae


The order contains only 10 genera and about 100 species. The family Cycadaceae contains the single genus Cycas, with 20 species. A sago (not to be confused with that from certain palms) is obtained from the pith of Cycas circinalis and C. revolula.



GINKGOALES



Ginkgoaceae


With the exception of Ginkgo biloba, the maidenhair-tree, the plants of this order are found only as fossils. In recent years, owing to their increasing use for the treatment of various diseases associated with the ageing process, the leaves of the ginkgo tree have been extensively investigated. For further details see ‘Diterpenoids’.



CONIFERAE (OR CONIFERALES)



Pinaceae


All members of the order are trees or shrubs; mostly evergreen with needle-like leaves; monoecious or dioecious. Sporophylls usually in cones. Resin ducts occur in all parts.


The Pinaceae are trees, rarely shrubs. Important genera are: Abies (50 spp.), Pseudotsuga (7 spp.), Tsuga (15 spp.), Picea (50 spp.), Larix (11 spp.), Cedrus (4 spp.), and Pinus (70–100 spp.). They are abundant in the northern hemisphere and extend southwards to Indonesia and Central America. Apart from their great value as timber and paper-making material, many species (e.g. Pinus) yield oleoresin (see ‘Colophony Resin and Crude Turpentine’). Other species are Abies balsamea, yielding Canada balsam; Pseudotsuga taxifolia (Douglas fir); Picea abies (Norway spruce); and Larix europaeus (larch). The barks of larch and hemlock spruce are tanning materials. Pinus pinea (the umbrella pine) produces large edible seeds (pignons). An extract of the bark of P. pinaster (P. maritima) var. atlantica containing bioflavonoids, particularly procyanidins (q.v.), is marketed as a food supplement (Pycnogenol®) having antioxidant properties. Some members of the family are a potential source of shikimic acid (q.v.).



Taxodiaceae


A small family of 10 genera, including Sequoia, Taxodium, Cryptomeria, Tetraclinis, Taiwania and Cunninghamia; 16 species.


The resin sandarac is produced in North Africa and Spain from Tetraclinis articulata. Some of the family contain antifungal diterpenes, others alkaloids.



Cupressaceae


A family of 19 genera and 130 species of trees and shrubs.


Members differ from the Pinaceae in that the leaves and cone-scales are usually opposite or whorled and the ovules erect. The genera include Callitris (16 spp., Australasia), Thuja (5 spp., China, Japan and North America), Cupressus (15–20 spp.), Chamaecyparis (7 spp.), Juniperus (60 spp., northern hemisphere). Juniperus communis yields juniper berries and volatile oil (q.v.); J. virginiana, the red cedar wood used for pencils; and J. sabina, volatile oil of savin; J. oxycedrus, by destructive distillation, yields oil of cade, which was formerly much used in veterinary work. This tar-like oil contains cadinene and phenols. Various diterpenes and flavonoids of the family have been studied.



Araucariaceae


Two genera and 38 species of trees, which sometimes have pungent leaves.


Araucaria (18 spp.) provides useful timbers; and Agathis (20 spp.), the resins known as copals or animes, which are used for varnish. Manila copal is obtained from the Malaysian Agathis alba; and kauri copal from A. australis, the kauri pine, in Australia and New Zealand. The best copals are usually those found in the ground long after the trees are dead.



Podocarpaceae


Six genera and 125 species of trees and shrubs. The largest genus, Podocarpus (100 spp.), extends from tropical to temperate zones and yields valuable timbers. A characteristic chemical feature of this genus is the widespread occurrence of norditerpene and bisnorditerpene dilactones; these compounds exhibit a variety of biological activities (see I. Kubo et al., Phytochemistry, 1992, 31, 1545).



Cephalotaxaceae


A family of one genus (Cephalotaxus) and seven species of trees and shrubs (plum yews) found from the eastern Himalayas to Japan. They have been intensively studied for their antitumour constituents in particular, the alkaloids harringtonine and homoharringtonine from C. harringtonia.



TAXALES



Taxaceae


An order of only one family, which includes the genera Taxus (10 spp.), Pseudotaxus, Torreya, Austrotaxus and Amentotaxus.


The common yew, Taxus baccata, produces valuable wood. The fruit has a fleshy red aril. All parts of the plant are very poisonous, and cattle and horses can die very rapidly after eating the leaves and stems. In addition to alkaloids, a cyanogenetic glycoside and antitumour agent have been reported in the genus.


Taxus brevifolia (the Pacific yew). The bark of this species yields the anticancer drug taxol, a nitrogenous diterpene. Low yields from the bark and the scarcity of raw material leading to damage to forests by, often illegal, over-collection hampered the development of the drug. The investigation of alternative sources led to tissue culture procedures for the production of taxol but the yields are still low. A development involving a renewable source has been the isolation of 10-deacetylbaccatin from the fresh needles of T. baccata in up to 0.1% yield and its chemical conversion to taxol. T. media, T. cuspidata and T. chinensis are other species investigated for taxane alkaloids.



GNETALES



Ephedraceae


The order consists of three families (Gnetaceae, Ephedraceae and Welwitchiaceae), three genera and about 70–75 species.


The Ephedraceae contains the single genus Ephedra (q.v.), about 40 species of shrubs. They occur in arid regions of the subtropics and tropics. Their seed, with two cotyledons, is enclosed in a perianth which becomes woody. Various species yield the drug ephedra (q.v.) and the alkaloid ephedrine.



ANGIOSPERMS: DICOTYLEDONS


The angiosperms or flowering plants include more than 250 000 species of herbs, shrubs and trees. The sporophylls (stamens and carpels) are usually arranged with other leaves (the perianth) to form a ‘flower’. The ovules are enclosed in a chamber (the ovary) formed from the carpels, and a stigma is provided for the reception and germination of the pollen. The embryo plant contained in the seed has one or two seed leaves or cotyledons. The wood almost invariably contains true vessels. The phylum is divided into monocotyledons and dicotyledons.


The dicotyledons are herbs, shrubs or trees, the seeds of which have two cotyledons. The leaves are usually reticulately veined and the typical stem structure is a ring of open vascular bundles. Unlike the monocotyledons, which typically have their floral parts in threes, dicotyledonous flowers are usually pentamerous or tetramerous. The flowers may be unisexual (e.g. Salicaceae), but are more usually bisexual. The perianth may or may not be differentiated into sepals and petals, and the latter may be free from one another or fused.


The classification adopted in the following pages is that of Engler, who divides the dicotyledons into two groups, the Archichlamydeae and Sympetalae. The Archichlamydeae are further divided into 37 orders and about 226 families and the Sympetalae into 11 orders and about 63 families.


The names of the orders terminate in ‘-ales’, suborders in ‘-neae’, families usually in ‘-aceae’ (Compositae, Gramineae and Labiatae are exceptions), and sometimes into subfamilies ending in ‘-oideae’.


The Archichlamydeae contain those families that in early editions were grouped under Monochlamydeae and Dialypetalae. The flowers have either no perianth or a perianth that is differentiated into sepals and petals, the latter being free. Engler’s classification of the Dicotyledons is given in a somewhat abbreviated form below.





























































































































Order Family
Subclass Archichlamydeae
Juglandales Myricaceae, Juglandaceae
Salicales Salicaceae
Fagales Betulaceae, Fagaceae
Urticales Ulmaceae, Moraceae (including Cannabinaceae) and Urticaceae
Proteales Proteaceae
Santalales Olacaceae, Santalaceae, Loranthaceae
Polygonales Polygonaceae
Centrospermae Phytolaccaceae, Caryophyllaceae, Chenopodiaceae
Cactales Cactaceae
Magnoliales Magnoliaceae, Winteraceae, Annonaceae, Eupomatiaceae, Myristicaceae, Canellaceae, Schisandraceae, Illiciaceae, Monimiaceae, Calycanthaceae, Lauraceae, Hernandiaceae
Ranunculales Ranunculaceae, Berberidaceae, Menispermaceae, Nymphaeaceae
Piperales Piperaceae
Aristolochiales Aristolochiaceae
Guttiferales Paeoniaceae, Dipterocarpaceae, Theaceae, Guttiferae
Sarraceniales Sarraceniaceae, Nepenthaceae, Droseraceae
Papaverales Papaveraceae (including Fumariaceae), Capparaceae, Cruciferae
Rosales Hamamelidaceae, Crassulaceae, Saxifragaceae, Rosaceae, Leguminosae, Krameriaceae
Geraniales Geraniaceae, Zygophyllaceae, Linaceae, Erythroxylaceae, Euphorbiaceae
Rutales Rutaceae, Simaroubaceae, Burseraceae, Meliaceae, Malpighiaceae, Polygalaceae
Sapindales Anacardiaceae, Aceraceae, Sapindaceae, Hippocastanaceae
Celastrales Aquifoliaceae, Celastraceae, Buxaceae
Rhamnales Rhamnaceae, Vitaceae
Malvales Elaeocarpaceae, Tiliaceae, Malvaceae, Bombacaceae, Sterculiaceae
Thymelaeales Thymelaeaceae, Elaeagnaceae
Violales Flacourtiaceae, Violaceae, Turneraceae, Passifloraceae, Cistaceae, Bixaceae, Tamaricaceae, Caricaceae
Cucurbitales Cucurbitaceae
Myrtiflorae Lythraceae, Myrtaceae, Punicaceae, Rhizophoraceae, Combretaceae, Onagraceae
Umbelliflorae Alangiaceae, Cornaceae, Garryaceae, Araliaceae, Umbelliferae
Subclass Sympetalae
Ericales Ericaceae
Primulales Myrsinaceae, Primulaceae
Plumbaginales Plumbaginaceae
Ebenales Sapotaceae, Ebenaceae, Styracaceae
Oleales Oleaceae
Gentianales Loganiaceae, Gentianaceae, Menyanthaceae, Apocynaceae, Asclepiadaceae, Rubiaceae
Tubiflorae Polemoniaceae, Convolvulaceae, Boraginaceae, Verbenaceae, Labiatae, Solanaceae, Buddlejaceae, Scrophulariaceae, Bignoniaceae, Acanthaceae, Pedaliaceae, Gesneriaceae, Myoporaceae
Plantaginales Plantaginaceae
Dipsacales Caprifoliaceae, Valerianaceae, Dipsacaceae
Campanulales Campanulaceae (including Lobeliaceae), Compositae


SUBCLASS ARCHICHLAMYDEAE



JUGLANDALES



Myricaceae and Juglandaceae


The order contains only these two small families.


The Myricaceae has three or four genera of trees and shrubs with unisexual flowers. Some members contain volatile oil (e.g. Myrica gale, the bog myrtle).


The Juglandaceae has seven or eight genera and the best-known species is the walnut, Juglans regia, which produces timber and edible nuts. Juglans contains the naphthoquinone juglone, the sugars raffinose and stachyose, flavonoids and phenolic acids.


The leaves and pericarp of J. regia have long been used as extracts in traditional medicine and pharmacologically demonstrated to be antihelmintic, antidiarrhoeal, antifungal, astringent, hypoglycaemic and, more recently, sedative; see M. Girzu et al., Pharm. Biol., 1998, 36, 280.



SALICALES



Salicaceae


The single family of the order contains only two genera, Salix (500 spp.) and Populus (35 spp.). The dioecious flowers are in catkins.


Both genera contain phenolic glycosides such as fragilin, salicin and populin. Salicin, formerly used in medicine, has been replaced by other drugs. Willow charcoal is the chief kind of wood charcoal used in Britain. Osiers (Salix purpurea and S. viminalis) are used for basket-making, and S. alba var. caerulea is used for cricket-bats. Species of Populus contain raffinose and stachyose. The dried winter buds of various species of poplar (P. nigra, P. candicans, P. tacamahaca) constitute Balm of Gilead Bud BHP 1996, BHC Vol 1, 1992. It is used as an expectorant and contains flavonoids, phenolic esters and free acids (caffeic acid, etc.). The hive product propolis may be derived from poplar bud exudates.



FAGALES



Betulaceae and Fagaceae


These families consist of monoecious trees and shrubs. Their classification together is confirmed by similarities in constituents.


The Betulaceae has two genera, Alnus (35 spp.) and Betula (60 spp.). Constituents include many phenolic substances such as myricetin, delphinidin and ellagic acid; also terpenoids such as lupeol and betulin. The wood of Betula alba is used for charcoal.


The Fagaceae has eight genera and about 900 species. Fagus (10 spp.) includes the beech, F. sylvatica, the nuts of which are expressed to yield oil; Castanea (12 spp.) includes the sweet chestnut, C. sativa, which yields timber and a bark used for tanning. The edible nut serves as a component of a gluten-free diet in cases of coeliac disease and in paediatrics for the treatment of gastroenteritis. For the isolation of a pyrrole alkaloid from the seeds, see A. Hiermann et al., Fitoterapia, 2002, 73, 22. Quercus (450 spp.) provides valuable timber. Different Quercus spp. contain shikimic acid (a cyclitol), methyl salicylate and terpenoids. The cupules and unripe acorns of Q. aegelops (valonia) are used in tanning. Q. ilex and Q. robur yield tanning barks and Q. tinctoria, a yellow dye. Q. suber affords the commonly used cork, in an industry worth (1987) some £120 million p.a. to Portugal’s economy; because there was no planned re-afforestation the industry now faces a decline. An extract of Q. stenophylla has been marketed for the acceleration of the elimination of renal and urethral calculi. Turkish galls (q.v.), an important source of tannic acid, are vegetable growths formed on the young twigs of the dyer’s oak, Q. infectoria, as a result of the activity of a gall-wasp. Similar galls are produced on the English oak, Q. robur.



URTICALES



Ulmaceae, Moraceae, Cannabinaceae, Urticaceae


The Cannabinaceae, originally included in the Moraceae, is now regarded as a separate family.


1 The Ulmaceae contains 15 genera and 200 species of tropical or temperate shrubs and trees. Genera include Ulmus (45 spp.), Celtis (80 spp.) and Trema (30 spp.). Members contain no latex (distinction from Moraceae). Mucilage is abundant in the barks of Ulmus rubra (see ‘Slippery Elm Bark’) and U. campestris; raffinose and stachyose occur in Ulmus, an indole alkaloid occurs in Celtis.

2 The Moraceae has about 53 genera and 1400 species. They are mainly tropical or subtropical shrubs or trees containing latex. The fruit is often multiple, as in Ficus, the fig. The large genus Ficus (about 800 spp.) includes trees and shrubs of very varied habit.These include F. benghalensis (banyan), F. elastica (indiarubber tree) and F. carica (common fig). The latex is often anthelmintic, owing to the proteolytic enzyme ficin. Another genus Castilloa (10 spp.), yields, from C. elastica, Panama rubber or caoutchouc. Among other constituents reported in the family are cardenolides (in five genera) and pyridine alkaloids (in two genera). Species of Morus are used in oriental medicine.

3 The Cannabinaceae or Cannabidaceae consists of the two genera Cannabis and Humulus comprising C. sativa (hemp), H. lupulus (common hop) (q.v.) and H. japonica (Japanese hop). The chemistry of these plants is a justification for their separation from the Moraceae. Cannabis produces the best hemp when grown in a temperate climate, whilst the more active samples of Indian hemp (q.v.) are usually associated with warmer climates.

4 The Urticaceae has 45 genera and 550 species; tropical or temperate herbs or undershrubs without latex. Some genera have stinging hairs (e.g. Urtica, 50 species of stinging nettle), others lack such-hairs (e.g. Pilea, Boehmeria and Parietaria). Root and leaf extracts of the common stinging nettle (q.v.) are used in herbal medicine, often in combination with other species, for the treatment of benign prostate hyperplasia. For a review with 78 references see E. Bombardelli and P. Morazzoni, Fitoterapia, 1997, 68, 387.


PROTEALES



Proteaceae


The single family of the order, the Proteaceae, contains 62 genera and 1050 species. Shrubs and trees are particularly abundant in Australia, New Zealand and South Africa. Many species have been examined chemically, and the constituents reported include cyanogenetic compounds, alkaloids, tannins, leucoanthocyanins, arbutin and the sugar alcohol polygalitol. Genera include Protea (130 spp.), Grevillea, Persoonia, Hakea and Knightia.



SANTALALES



Olacaceae, Santalaceae, Loranthaceae


The order contains seven families of which only four need be mentioned.


The Olacaceae has about 27 genera and 250 species. Few have been examined chemically. Acetylenic acids occur in Olax stricta.


The Santalaceae contains about 30 genera and 400 species. Of the genera, Santalum contains 25 species and Thesium about 325 species. Monoterpenes and sesquiterpenes occur in several genera. The plants are hemiparasitic herbs, shrubs and small trees. Santalum album yields sandalwood and sandalwood oil (q.v.) and is rich in sesquiterpene alcohols. Australian sandalwood and its oil are obtained from another member of the family, Eucarya spicata.


The Loranthaceae is a fairly large family of 36 genera and 1300 species. The genus Viscum consists of about 60 species of parasitic evergreen shrubs, which often contain cyclitols. The dried aerial parts of the common mistletoe, Viscum album, which grows on apple and other trees are included in the BHP 1996 and are used for various circulatory conditions. It contains glycoproteins (the mistletoe lectins), polypeptides (viscotoxins), lignans, flavonoids, etc. The flavonoid glycosides involve glucose, apiose and trans-cinnamic acid; for glycoside isolations from V. album ssp. atlantica grown on apricot (Armeniaca vulgaris) in Turkey, see D. Deliorman Orhan et al., Pharm. Biol., 2002, 40, 380.



POLYGONALES



Polygonaceae


This one-family order occupies an isolated position. It has about 40 genera and 800 species, mostly herbs. About 29 species are indigenous to Britain. Genera include Rheum (50 spp.), Rumex (about 180 spp.), Fagopyrum (15 spp.), Coccoloba (150 spp.) and Polygonum. The fruit is a one-seeded, usually three-winged nut (e.g. dock and buckwheat). Anthocyanin pigments are common; also flavones and flavonols—for example, buckwheat, Fagopyrum esculentum, is a commercial source of rutin. Quinones (anthraquinones, phenanthraquinones, anthrones and dianthrones) are found in many species of Rheum (q.v.), Rumex and Polygonum. The root of Rumex crispus (yellow dock, curled dock), BHP 1983, contains hydroxyanthraquinone derivatives; it is indicated for the treatment of chronic skin diseases, obstructive jaundice and psoriasis.



CENTROSPERMAE



Phytolaccaceae, Caryophyllaceae, Chenopodiaceae


The order contains 13 families which show a passage from the monochlamydeous type of flower (e.g. Phytolaccaceae and Chenopodiaceae) to the dichlamydeous type of flower (e.g. Caryophyllaceae). Most families of the order, except the Caryophyllaceae, produce characteristic betacyanin and betaxanthin pigments, which indicate affinity with the Cactales (the next order, below).


The Phytolaccaceae is a family of 12 genera and 100 species; herbs, shrubs and trees, found particularly in tropical America and South Africa. Phytolacca (35 spp.) includes Phytolacca americana (Poke root), the leaves and roots of which have been found as an adulterant of belladonna: its berries contain a dyestuff. The roots which contain saponins are included in the BHP (1996) for the treatment of rheumatic diseases; however, arising from its toxicity the drug is not strongly recommended and excessive use should be avoided. The toxicity is primarily due to mitogenic proteins (lectins) and triterpene saponins. Other species have been shown to have molluscicidal activity.


The Caryophyllaceae has 70 genera and about 1750 species, mostly herbs, and is wide-spread. Genera include Saponaria, Stellaria, Arenaria, Spergularia, Herniaria, Silene, Lychnis, Gypsophila (125 spp.) and Dianthus (300 spp.). Many of these plants are rich in saponins. The root of Saponaria officinalis has been included in many pharmacopoeias. It contains about 5% of saponins and is widely used as a domestic detergent.


The Chenopodiaceae contains 102 genera and 1400 species; most grow naturally in soils containing much salt (halophytes). Genera include Beta (6 spp.), Chenopodium (100–150 spp.), Salicornia, Atriplex and Anabasis. From the wild Beta vulgaris (sea-beet) have been derived garden beetroot, sugar-beet and the mangold-wurzel. Chenopodium anthelminticum yields the anthelmintic Mexican tea or ‘wormseed’ and its oil of chenopodium (q.v.).



CACTALES



Cactaceae


The Cactaceae is the only family of the order and contains from 50 to 150 genera and about 2000 species. The plants are xerophytes and, with possibly one exception, are all native to the Americas. They will not grow where there is virtually no rainfall, but thrive in deserts where there is a reasonable rainfall even if rain occurs very infrequently. Some cacti occur in rain forests, where they are often epiphytes (e.g. Epiphyllum). The majority are succulent and store water in their stems. The plant body is usually globular or cylindrical and bears wool, spines and flowers, but in Epiphyllum the stems are flattened and consist of jointed segments, which are often mistaken for leaves. Among the genera are Epiphyllum (21 spp.), Opuntia (250 spp.), Cephalocereus (48 spp.), Cereus (50 spp.) and Echinocereus (75 spp.). The leaves of Opuntia and Nopolea provide food for cochineal insects (q.v.). Opuntia ficus-indica, the prickly-pear, is sometimes grown as a hedge but can become a troublesome weed. Dried cactus flowers (Opuntia spp.) are used as an astringent herbal remedy. O. dillenii finds various medicinal uses in India. Lophophora williamsii is the plant producing peyote, anhalonium or ‘mescal buttons’; it contains mescaline (q.v.). Several genera contain simple isoquinoline alkaloids; cyanogenetic glycosides are very rare or absent; most species contain abundant mucilage.



MAGNOLIALES



Magnoliaceae, Winteraceae, Annonaceae, Myristicaceae, Canellaceae, Schisandraceae, Illiciaceae, Monimiaceae, Lauraceae and Hernandiaceae


This order contains 22 families.


1 The Magnoliaceae contains 12 genera and about 230 species, which occur in both temperate and tropical regions. They are trees or shrubs with oil cells in the parenchyma. Genera include Magnolia (180 spp.), Michelia (50 spp.) and Liriodendron (1 sp.), tulip tree. The remedial properties of L. tulipifera, which is reported to contain alkaloids (e.g. dihydroglaucine) and sesquiterpenes, have been assessed (Crellin, J. K. Pharm. J., 1988, 240, 29).

2 The Winteraceae comprises 7 genera and 120 species. Drimys winteri (Winter’s bark) has been much used for its stimulant and tonic properties and a number of pharmacological investigations have been reported in the literature. The bark contains volatile oil, sesquiterpenes, lactones, flavonoids and polygodial derivatives (V. C. Filho et al., J. Ethnopharmacology, 1998, 62, 223).

3 The Annonaceae contains 120 genera and about 2100 species, which are found mainly in the tropical regions of the Old World. Genera include Uvaria (150 spp.), Xylopia (100–150 spp.), Monodora (20 spp.) and Annona (120 spp.). The seeds of Monodora myristica are used like nutmegs. Many members of the family contain alkaloids mainly of the isoquinoline type. The family is of importance in folk medicine.

4 The Myristicaceae is a family of 18 genera and 300 species, which are mainly found in tropical Asia. Genera include Myristica (120 spp.), Virola (60 spp.), Horsfieldia (80 spp.) and Knema (37 spp.). The flowers are dioecious and consist of an inconspicuous three-lobed perianth with 3–18 monadelphous stamens or a solitary carpel containing a basal anatropous ovule. The fruit is a fleshy drupe, which splits along both dorsal and ventral sutures. The single seed is more or less completely enveloped in a lobed aril. The chemistry of the family has not been thoroughly investigated. Some species (see ‘Nutmeg’ and ‘Mace’) contain volatile oil and hallucinogenic substances.

5 The Canellaceae is a small family of five genera and 16 species; trees with gland-dotted leaves. Fruit is a berry. Genera include Canella, Cinnamodendron and Warburgia. Canella bark, a spice, is obtained from Canella alba, grown in the Bahamas and Florida.

6 The Schisandraceae comprises two genera and 47 species of climbing shrubs. Schisandra has 25 species; lignans are common constituents. S. chinensis produces antihepatoxic constituents (q.v.).

7 The Illiciaceae, sometimes classified under Magnoliaceae, has the single genus Illicium (42 spp.), found in Asia, Atlantic North America and the West Indies. See ‘Star-anise Fruit and Oil’.

8 The Monimiaceae includes 20 genera and 150 species of trees and shrubs, which often contain volatile oil and resin. In South America there are many traditional uses of plants of this family; G. G. Leitao et al. (J. Ethnopharmacology, 1999, 65, 87), have reviewed the pharmacology and chemistry. The genera include Hedycarya (25 spp.) and Peumus (one sp.). Peumus boldus (q.v.) has a hard wood, its bark yields a dye and its leaves contain the alkaloid boldine.

9 The Lauraceae has 32 genera and about 2000–2500 species. These are tropical or subtropical trees and shrubs with leathery, evergreen leaves; the flowers are usually bisexual (e.g. Cinnamomum), rarely unisexual (e.g. Laurus). The fruit is a berry or drupe. Alkaloids, volatile oils and fixed oils occur in many species. Volatile oil cells occur in the leaves and cortex. Genera include Persea (150 spp.), Ocotea (300–400 spp.), Cinnamomum (250 spp.), Aniba (40 spp.), Litsea (400 spp.), Neolitsea (80 spp.), Lindera (100 spp.), Laurus (2 spp.) and Cryptocarya (200–250 spp.). A number of Taiwanese species of the above genera have been tested for bioactivity (C. T. Lin et al., Pharm. Biol., 2007, 45, 638).

The bark of Cryptocarya massoia yields an essential oil that has a coconut-like aroma and is used as a cosmetic additive, e.g. in shampoos; C. moschata gives the mace of Brazilian nutmeg. The bay laurel, Laurus nobilis, is the only European representative of the family; 45 constituents of the essential oil have been identified, the principal one being 1,8-cineole. Other constituents of the leaves are glycosylated flavonoids, (−)-epicatechin, (+)-catechin, (+)-epigallocatechin and procyanidins. For research and other references, see C. Fiorini et al., Phytochemistry, 1998, 47, 1821; M. Simic× et al., Fitoterapia, 2003, 74, 613; S. D. Acqua et al., Chem. Pharm. Bull., 2006, 54, 1187. For drugs see ‘Cinnamon bark’, ‘Cassia bark’ and ‘Camphor’.


10 The Hernandiaceae has three genera and 54 species. Members are tropical trees, shrubs or lianes with oil cells. Species of Hernandia (24 spp.) contain tumour-inhibiting alkaloids and lignans including podophyllotoxin; they have been used in traditional Samoan medicine. About 128 alkaloids belonging to 17 structural types are known for the family, see L. M. Conserva et al., The Alkaloids, 2005, 62, 175.


RANUNCULALES:



Ranunculaceae, Berberidaceae, Menispermaceae and Nymphaeaceae


Of the seven families in this order the above four are of medicinal interest. The families show a considerable variety of plant constituents and alkaloids are very common. In the four named families the alkaloids are often based on benzylisoquinoline, bisbenzylisoquinoline or aporphine.


1 The Ranunculaceae comprises 59 genera and about 1900 species. The plants are mostly perennial herbs with a rhizome or rootstock. They are well represented in Britain. Many members are poisonous. The flowers are bisexual, regular (e.g. Ranunculus) or zygomorphic (e.g. Aconitum). The perianth is simple or differentiated into calyx and corolla. The stamens are numerous and free. The carpels are usually numerous in the regular flowers or fewer in the zygomorphic ones. The fruit is an etaerio of achenes or follicles, or a berry. Genera include Helleborus (20 spp.), Aconitum (300 spp.), Thalictrum (150 spp.), Clematis (250 spp.), Actaea (10 spp.), Ranunculus (400 spp.), Anemone (150 spp.), Delphinium (250 spp.), Adonis (20 spp.) and Hepatica (10 spp.). The family has diverse chemical constituents and is of considerable phytochemical and chemotaxonomic interest. For example, the chromosomes, basedon size and shape, fall into two distinct groups, the Ranunculus type (R-type) and the Thalictrum type (T-type). The glycoside ranunculin has been found only in plants of the R-type. This glycoside hydrolyses to protoanemonin, which is vesicant and accounts for this property in many species. Isoquinoline-derived alkaloids occur in Thalictrum, Aquilegia and Hydrastis; diterpene-derived alkaloids in Delphinium and Aconitum. Saponins, mainly triterpenoid, occur in Ranunculus, Trollius, Clematis, Anemone and Thalictrum, cyanogenetic glycosides in Ranunculus and Clematis; cardenolides in Adonis, bufodienolides in Helleborus. Black hellebore rhizome, from Helleborus niger, contains very powerful cardiac glycosides but is now little used in medicine. Various aconite roots, containing highly toxic alkaloids (q.v.) have also lost much of their former popularity. Black Cohosh BHP 1996 is the dried rhizome of Cimicifuga racemosa; it contains triterpenoid glycosides structurally related to cycloartenol, also isoflavones including formononetin. The drug contains substances with endocrine activity and is used in herbal medicine to treat menopausal and other female disorders, and also various rheumatic conditions. A number of other species e.g. C. simplex, are used in Chinese medicine (see, for example, A. Kussano et al., Chem. Pharm. Bull., 1999, 47, 1175). The European C. foetida (bugbane) is a traditional vermin preventative.

2 The Berberidaceae has 14 genera and about 575 species, they are perennial shrubs usually with spiny leaves. The flowers are hermaphrodite, regular and hypogynous. The perianth is differentiated into calyx and corolla. The stamens are generally in two whorls and the ovary is composed of one carpel. The fruit is a berry with one to numerous seeds. Genera include Berberis (450 spp.), Mahonia (70 spp.), Epimedium, Vancouveria and Leontice.

The Berberidaceae contains alkaloids of the benzylisoquinoline, bisbenzylisoquinoline and aporphine types. Leontice contains an alkaloidal amine and quinolizidine. Lignans such as dehydro-podophyllotoxin occur; also triterpenoid saponins. The root tubers of Leontice leontopetalum contain saponin and alkaloids and have been used for the treatment of epilepsy. For other drugs see under ‘Hydrastis’, ‘Podophyllum’ and ‘Indian Podophyllum’.


In some members of the family there is a close resemblance to the Ranunculaceae. Hydrastis, for example, is sometimes placed in the Ranunculaceae in the same tribe as the peony. There are also relationships with the Papaveraceae, narcotine being found in both families.


3 The Menispermaceae is a family of 65 genera and 350 species; mainly tropical twining shrubs, herbs or trees. The plants usually have palmately lobed leaves and dioecious flowers. Anomalous stem structure is frequently found and abnormal secondary growth often takes place in the roots (e.g. of Chondodendron tomentosum), successive cambia being produced to give concentric rings of wood. The broad primary medullary rays found in the stem of Coscinium are a family characteristic. The fruit is a drupe the dorsal side of which develops more rapidly than the ventral, as in the fish berry Anamirta cocculus. These contain the highly toxic substance picrotoxin. For drugs see ‘Calumba’ and ‘Curare’.

The genera include Chondodendron (8 spp.), Tiliacora (25 spp.), Triclisia (25 spp.), Anamirta (1 sp.), Coscinium (8 spp.), Tinospora (40 spp.), Jateorhiza (2 spp.), Abuta (35 spp.), Cocculus (11 spp.), Menispermum (3 spp.), Stephania (40 spp.), Cissampelos (30 spp.) and Cyclea (30 spp.).


Alkaloids are important constituents of the family and have been reviewed (J. M. Barbosa-Filho et al., The Alkaloids, 2000, 54, 1). Saponins are present in many species. Coscinium fenestratum (‘false calumba’, ‘tree turmeric’) stems are widely used in SE Asia and India for the treatment of a variety of ailments. The principal alkaloid constituents are berberine and jatrorrhizine, the former being responsible for its antibacterial activity (G. M. Nair et al., Fitoterapia, 2005, 76, 285); for an investigation of the hypotensive and toxicological properties of an extract, see T. Wongcome et al., J. Ethnopharm., 2007, 111, 468. Stephania pierrii (S. erecta) contains bisbenzylisoquinoline alkaloids and is used in Thai folk medicine as a muscle relaxant. Tinospora cordifolia is used in Ayurvedic medicine and a considerable number of pharmacological actions, including immunomodulatory, have been demonstrated for the drug. For other drugs see ‘Calumba’ and ‘Curare’.

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Jul 18, 2016 | Posted by in PHARMACY | Comments Off on taxonomic approach to the study of medicinal plants and animal-derived drugs

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