Scutellaria lateriflora L.

Cassida lateriflora (L.) Moench

Lamiaceae (Labiatae)

American skullcap; helmet flower; hoodwort; quaker bonnet; scullcape.

Scutellariae herba (Note: Scutellariae radix refers to the drug used in TCM, the root of a related species, S. baicalensis Georgi)

Dried aerial parts

The major constituents of aerial parts of S. lateriflora are flavonoid glycosides, and their aglycones: predominantly baicalin (∼5%), with dihydrobaicalin, baicalein, lateriflorin, lateriflorein, ikonnikoside I, scutellarin, oroxylin A, 2′-methoxy-chrysin-7-O-glucuronide, wogonin and wogonoside. The leaf contains significantly higher concentration of flavonoids (over 5%) than the roots (around 3%) or stems (around 2%) and flowering plants contain the highest amount of flavonoids. Phenolic acids found in skullcap herb include caffeic, cinnamic, p-coumaric and ferulic acids. The essential oil concentration and composition is uncertain due to conflicting data, and may be the result of misidentification of plant species. Diterpenoids (neo-clerodanes) reported include scutelaterins A-C and scutecyprol A. Other constituents include potentially active constituents such as γ-aminobutyric acid (GABA) and melatonin, which have been found at low levels (Pharmaceutical Press Editorial Team 2013; Upton and Dayu 2012).

S. baicalensis roots contain similar flavonoids: baicalin, baicalein, oroxylin A, skullcap flavone I and II, tenaxin I, wogonin, wogonoside and many other hydroxylated and methoxylated flavones (Li et al. 2011; Williamson et al. 2013).

Clinical data for S. lateriflora