Three saponins hederagenin-3-O-(4-O-acetyl-β-d-xylopyranosyl)-(1 → 3)-α-l-hamnopyranosyl-(1 → 2)-α-l-arabinopyranoside, hederagenin-3-O-(3,4-di-O-acetyl-β-d-xylopyranosyl)-(1 → 3)-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranoside and hederagenin-3-O-(3,4-di-O-acetyl-α-l-arabinopyranosyl)-(1 → 3)-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranoside were isolated from the fruits (Kojima et al. 1998).

Proximate nutrient composition of the seed was reported as crude fat 24.70 %, crude protein 18.7 %, crude fibre 3.01 %, ash 4.06 %, moisture 4.10 %, carbohydrate 45.41 %, Na 342.57 ppm, K506.55 ppm, Ca 293.10 ppm, Mg 83.65 ppm, Fe 128.11 ppm, Cu 1.10 ppm, Zn 21.78 ppm and Mn 32.30 ppm (Adewuyi et al. 2009). The lipid classes of the seed oil comprised polar lipids 7.50 %, sterols 2.70 %, diacylglycerols 5.30 %, monoacylglycerols 4.60 %, triacylglycerols 75.60 %, hydrocarbons 1.90 % and free fatty acids 2.40 %. The mineral content of the seed oil comprised Na 281.10 ppm, K 432.60 ppm, Ca 271.10 ppm, Mg 64.70 ppm, Fe 102 ppm, Cu 0.60 ppm, Zn 16.80 ppm and Mn 22.98 ppm. The physicochemical characteristics of the seed oil was reported as colour orange, acid value 1.40 mg KOH/g, free fatty acid 0.80 %, saponification value 94.4 mg KOH/g, iodine value 87.60 mg I/g, unsaponifiable matter 1.00 %, peroxide value 0.40 mg O₂/g oil, refractive index (25 °C) 1.4, specific gravity (25 °C) 0.876 and sate at room temperature liquid. The composition of the unsaponifiables of the seed oil comprised n-alkanes 21.20 %, triterpene alcohols 31 %, sterols 29.4 % and unknowns 18.40 % (Adewuyi et al. 2009).

Sotelo et al. (1986) have reported a thermostable non-protein amino acid toxin canavanine (2-amino-4-guanidooxy-butyric acid) in gliricidia seeds which killed mice within l week of feeding and may be associated with the toxicity of gliricidia in non-ruminants.

In the flower essential oil, the major compounds were coumarin (43.1 %), hydroquinone (21.6 %), myrtenol (12.73 %) and maltol (4.62 %) (Kaniampady et al. 2007). Other compounds included p-mentha-1,8-dien-9-ol 1.83 %, octanoic acid 1.53 %, 3-nonanol 1.5 %, 2-butyl-2-hexanol 1.46 %, γ-nonalactone 1.31 %, 2-octanoic acid 1.26 %, 2-butyl-3-hexenol 1.03 %, eucarvone 0.88 %, myrtenal 0.78 %, p-mentha-1,4-diene-2-ol 0.73 %, geraniol 0.72 %, p-mentha-1,4-diene-7-ol 0.71 %, dodecanoic acid 0.64 %, nonanol 0.62 %, tetradecanoic acid 0.46 %, allyl tiglate 0.44 %, 4-hydroxy-3-methylacetophenone 0.37 %, 3tetradecanoic acid 0.36 %, benzyl alcohol 0.35 %, decanoic acid 0.31 % and dihydrocarveol acetate 0.30 %.

Jose and Reddy (2010) reported the following chemical composition of the flower essential oil: coumarin 43.07 %, hydroquinone 21.64 %, myrtenol 12.73 %, maltol 4.42 %, p-mentha-1,8-dien-1-ol 1.83 %, γ-nonalactone 1.31 %, 2-butyl-2-hexanol 1.03 %,eucarvone 0.88 %, myrtenal 0.78 %, p-mentha-1,4-dien-2-ol 0.73 %, geraniol 0.72 %, p-mentha-1,4-dien-7-ol 0.71 %, dodecanoic acid 0.64 %, nonanol 0.62 %, nonanoic acid 0.55 %, tetradecanoic acid 0.46 %, benzyl alcohol 0.35 % and decanoic acid 0.31 %.

G. sepium leaf meal was found to have the following amino acid composition: threonine 1.2 %, valine 1.60 %, cysteine 0.39 %, methionine 0.42 %, isoleucine 1.20 %, leucine 2.41 %, tyrosine 1.12 %, phenylalanine 1.54 %, lysine 1.12 %, histidine 0.51 % and arginine 1.59 % (Chadhokar 1982).

The leaves were found to contain coumarin, O-coumaric acid and melilotic acid (Griffiths 1962), cyanogenic glycoside, nitrate (Manidool 1985), pinitol (Calle et al. 1987), condensed tannins (Ahn et al. 1989) and lignans (pinoresinol and lariciresinol) (Ragasa et al. 2000). G. sepium leaves were found to contain condensed tannins (CT) which were all bound to proteins (Jackson et al. 1996). Two new triterpene saponins (1 and 2) possessing 3β,21β,24-trihydroxy-22-oxoolean-12-ene as an aglycon and oligosaccharide moiety linked to C-3 of the aglycon were isolated from leaves and roots (Rastrelli et al. 1999b). They contained two pyranoses (glucuronic acid and xylose) and the glucose residue of both 1 and 2 was also linked to C-21.

The major compounds of the leaf essential oil were propylene glycol (25.1 %), coumarin (18.2 %), (Z)-3-hexenol (17.7 %), β-farnesene (14.2 %) and (E)-2-hexenol (6.5 %) (Kaniampady et al. 2007). Other compounds included thymol (3.6 %), benzyl alcohol 3.5 %, caryophyllene (2.3 %), α-farnesene (2.0 %), 2-pentene-1-ol (<1 %), isovanillin (<1 %), isobutyl alcohol (<1 %), phenylethyl alcohol (<1 %), phenol (<1 %), crotonic aldehyde (<1 %) and 5,6-dihydro-4H-cyclopenta-(6)-furan (<1 %). Jose and Reddy (2010) reported the following chemical composition of the leaf essential oil: propylene glycol 25.1 %, coumarin 18.2 %, (Z)-2-hexenol 17.7 %, β-farnesene 14.2 %, (E)-2-hexenol 6.5 %, thymol 3.6 %, benzyl alcohol 3.5 %, caryophyllene 2.3 %, α-farnesene 2.0 %, 2-pentene-1-ol <1 %, isovanillin <1 % < isobutyl alcohol <1, phenylethyl alcohol <1 %, phenol <1 %, crotonic aldehyde <1 % and 5,6-dihydro-4H-cyclopenta-(6)-furan <1 %.

Jurd and Manners (1977) isolated two new isoflavones, 2′,3′,7-trihydroxy-4′-methoxyisoflav-3-ene (sepiol) and 3′,7-dihydroxy-2′,4′-dimethoxyisoflav-3-ene (2′-O-methysepiol); a new phenolic isoflavan, robinetin; and 7,3′,4′-trihydroxyflavanone from gliricidia heartwood. Three additional flavonoid constituents (an isoflavone, a dihydroflavonol and a β-hydroxydihydrochalcone) were isolated from the wood (Manners and Jurd 1979). An isoflavan, 7,4′-dihydroxy-3′-methoxyisoflavan, along with three other isoflavonoids (isovestitol, formononetin and afrormosin), a pterocarpan, medicarpin, 4-hydroxy-3-methoxy-cinnamaldehyde (Herath et al. 1998), stigmasterol glucoside and 3′,4′-dihydroxy-trans-cinnamic acid octacosylester, along with three other known constituents (Herath and de Silva 2000), were isolated from the heartwood. From the methanol extract of Gliricidia sepium bark, Rastrelli et al. (1999a) isolated in addition to vestitol and 2′-O-methylvestitol, three new 12α-hydroxyrotenoids: gliricidol, 2-methoxygliricidol and gliricidin. Hederagin was also isolated from the roots (Rastrelli et al. 1999b).

Nineteen compounds were identified and quantified from the bark volatile oil of Gliricidia sepium (Reddy and Jose 2010a). The major components were methyl‐3(E)‐pentenyl ether (11.55 %), 3‐methyl‐2‐butanol (10.65 %), 3‐methoxy hexane (10.14 %), 1‐(1‐ethoxyethoxy)‐2‐hexene (9.72 %), 2‐decanol (8.97 %), coumarin (8.07 %) and hexadecanoic acid (5.16 %). Other components included humulene epoxide (3.64 %), caryophyllene oxide (3.05 %), 2,4‐dimethyl‐3‐hexanol (2.79 %), 2‐ethyl hexanol (2.61 %), dodecanoic acid (2.37 %), methyl‐3(E)‐hexenyl ether (2.19 %), 4‐ethoxy ethyl benzoate (2.1 %), 1‐hexanol (1.92 %), T‐muurolol (1.77 %), tetradecanoic acid (1.23 %), octadecanal (1.11 %) and methyl‐3‐butenyl ether (1.02 %).

G. sepium ethanol extract exhibited low DPPH radical scavenging activity but showed the highest ferric reducing antioxidant property of 88 % (Akharaiyi et al. 2012). G. sepium extract had the highest concentration of phenol with a value of 1.7 mg/ml and flavonoid content with a value of 0.46 mg/ml.

Of 153 Panamanian plants tested, the crude plant extracts of G. sepium were one of three that showed most promising inhibitory activity in-vitro against Candida albicans and Cladosporium cucumerinum (Rahalison et al. 1993).

The methanol bark extracts of G. sepium exhibited antimicrobial effects against Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus pumilus and Vibrio cholerae at doses of 200 μg (Pérez et al. 2001). Gliricidia sepium leaf alcohol extract was one of ten Guatemalan plants found to be most active in-vitro against five strains of Neisseria gonorrhoeae (Cáceres et al. 1995), and the bark and leaf extracts were found to be inhibitory to four pathogenic fungi, namely, Aspergillus flavus, Epidermophyton floccosum, Microsporum gypseum and Trichophyton rubrum (Cáceres et al. 1993). G. sepium bark oil exhibited pronounced activity against all tested microorganisms Bacillus cereus, Enterobacter faecalis, Salmonella paratyphi, Staphylococcus aureus, Escherichia coli, Streptococcus faecalis, Proteus vulgaris, Klebsiella pneumoniae, Pseudomonas aeruginosa and Serratia marcescens, and its activity was quite comparable with the standard antibiotics screened under similar conditions (Reddy and Jose 2010a).

Lignans: pinoresinol and lariciresinol isolated from gliricidia leaves exhibited low antimicrobial activity against Bacillus subtilis and Pseudomonas aeruginosa and antifungal activity against Trichophyton mentagrophytes and Aspergillus niger (Ragasa et al. 2000). The ethanol leaf extract of G. sepium exhibited antibacterial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas spp., Salmonella typhi and Klebsiella spp., with the best result against E. coli (Nazli et al. 2008).

The methanol, ethyl acetate and chloroform extracts of Gliricidia flowers exhibited significant activity against all the tested organisms, namely, Bacillus cereus, Enterobacter faecalis, Salmonella paratyphi, Staphylococcus aureus, Escherichia coli, Streptococcus faecalis, Proteus vulgaris, Klebsiella pneumoniae, Pseudomonas aeruginosa and Serratia marcescens (Reddy and Jose 2010b). Flower aqueous extract was found to be effective on Escherichia coli, Proteus vulgaris, Bacillus cereus, Enterobacter faecalis, Pseudomonas aeruginosa, Staphylococcus aureus and Serratia marcescens but elicited little effect on Salmonella paratyphi, Klebsiella pneumoniae and Streptococcus faecalis. The bark ethyl acetate extract exhibited marked activity against Bacillus cereus, Enterobacter faecalis, Salmonella paratyphi, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa and Serratia marcescens but was inactive against Staphylococcus aureus, Streptococcus faecalis and Klebsiella pneumoniae. The bark methanol extract was found to be active against Bacillus cereus, Enterobacter faecalis, Salmonella paratyphi, Streptococcus faecalis, Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus and Proteus vulgaris but was inactive against Escherichia coli and Klebsiella pneumoniae. Both chloroform and aqueous extracts of Gliricidia sepium bark inhibited the growth of Bacillus cereus. Chloroform extract inhibited Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. Bark aqueous extract exhibited appreciable activity against Serratia marcescens, Bacillus cereus, Salmonella paratyphi and Streptococcus faecalis but was less active against Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae. Petroleum ether extracts of bark, leaf and flower had no antibacterial activity on the test microorganisms.