Chemical Constituents of Rhododendron lepidotum
Two new coumarin glycosides, 7-O-β-D-glucopyranosyl-8-methoxybenzopyranone (1) and 7-hydroxy-8-O-β-glycosylbenzopyranone ((2), are reported along with the isolation of 7,8-dihydroxy coumarin (daphnetin) from Rhododendron lepidotum (aerial part).
7α-Hydroxyfriedelan-3-one-26-ol-29-oic acid and other Constituents from Pileostegia viburnoides var. glabrescens.
Phytochemical investigation of the roots and rhizomes of Pileostegia viburnoides var. glabrescens led to the isolation and identification of 31 compounds (1-31), 25 of which (1-2, 4-7, 9-12, 15-18, 21-31) were isolated from the Pileostegia genus for the first time. 7α-Hydroxyfriedelan-3-one-26-ol-29-oic acid (1) is a new friedelane-type triterpene. The structure of n-butyl-β-D-fructopyranoside (2) was determined by single-crystal X-ray diffraction. Compounds 4 and 12 displayed marginal cytotoxicity against the P388 murine leukemia cell line with IC₅₀ values of 13.4 μM and 25.0 μM, respectively. Compound 23 exhibited marginal anti-inflammatory activity by the inhibition of lipopolysaccharide induced nitric oxide production in RAW 264.7 macrophage cells, with an IC₅₀ value of 32.0 μM. Compounds 3, 8-10, 25, and 27 were phytotoxic to the dicot Lactuca sativa (lettuce) and/or the monocot Agrostis stolonifera (bentgrass).
Two new benzofuran-type lignans from the wood of Viburnum awabuki
New benzofuran-type lignans, vibsanol (1) and 9'-O-methylvibsanol (2), along with dihydrodehydrodiconiferyl alcohol (3), have been isolated from the wood of Viburnum awabuki (Caprifoliaceae). Their structures have been elucidated mainly on the basis of spectroscopic data. The antioxidant property of new compounds has been evaluated.