CHEMICAL CONSTITUENTS OF Rhododendron lepidotum FROM NEPAL HIMALAYAS

摘要

Rhododendron lepidotum (family Ericaceae) is a highly variable, low and compact to upright, lean shrub, up to 2 m tall, The flowers are of open type, having a white, yellow, pink, or purple color. The leaves are elliptic with a dark green upper surface and a lower surface with large brownish scales. The distribution of R. lepidotum is from Kashmir to southeastern Tibet at an altitude ranging from 2400 to 4900 m. The genus Rhododendron has a long history of use as folk medicine in various countries. Rhododendron adamsii Rehder is used as a stimulant and tonic. Dried leaves of R. dauricum are used as an expectorant and in the treatment of acute and chronic bronchitis. The leaves and twigs of R. dauricum display significant anti-HIV activity. The leaf and flower powder of R. lepidotum have been used as a snuff in the treatment of headache, etc. Coumarin glycosides such as rhodonin and rhodonetin, 7-O-β-D-glucopyranosyl-8-methoxybenzopyranone and 7-hydroxy-8-O-β-glycosylbenzopyranone, coumarins named daphnin, daphnetin, daphnetin glucoside, rhodonetin, rhodonin, and umbelliferone, 2,4,6-trihydroxacetophenone-3,5-di-C-β-D-glucoside, lupeol, ursolic acid, avicularin, quercetin, myricetin, hyperoside, myricetin-3'-O-β-D-xyloside, (+)-taxifolin-3-O-α-L-arabinopyranoside, (+)-taxifolin-3-O-β-D-glucopyranoside, lyoniside, confluentin, 2-(4-hydroxyphenyl)-ethyltriacontanoate,2,6-dimethoxy-4-hydroxyphenyl-1-O-β-D-glucopyranoside, (-)-2-hydroxy-5-(2-hydroxyethyl)phenyl-O-β-D-glucopyranoside, (-)-isolariciresinol, and isofraxoside [10] have been isolated from R. lepidotum.