Sideritis leucantha

Another flavonoid, hypolaetin-8-glucoside, found in many species of the genus Sideritis, is traditionally used in Spain for its antiinflammatory and digestive properties [115, 116], It was isolated from Sideritis leucantha and its antiulcerogenic properties studied by Alcaraz and Tordera [117]. The authors found that this compound significantly reduces the gastric lesions induced by absolute ethanol, acetyl salicylic acid and, Shay s pyloric ligature. 

Six new kauranoid diterpenes[(62)—(64) and their A -isomers] have been isolated from Sideritis leucantha three (62—64) of them also occur in S. lineari-folia. Foliol (62), sidol (63), and linearol (64) gave the same triacetate, which was isomerized with iodine to the triacetate obtained from isofoliol, isosidol, and isolinearol. These contain the C-15(16) double bond. Foliol was oxidized with chromium trioxide in pyridine to a diketo-aldehyde which was reduced to (— )-kaurene. The location of the oxygen functions at C-3a, C-ip, and C-18 were inferred from the n.m.r. spectrum and from the formation of a 3o ,18-acetonide. 

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