Zhongxin Xi

Three new sesquiterpenes from Tithonia diversifolia and their anti-hyperglycemic activity

Three new germacrane sesquiterpenes (1), (2), (3), along with eleven known sesquiterpenes, namely, tirotundin-3-O-methyl ether (4), deacetylvguiestin (5), 1β-hydroxydiversifolin-3-O-methyl ether (6), tagitinin C (7), 1β-hydroxytirotundin-3-O-methyl ether (8), 1β-hydroxytirotundin-1,3-O-dimethyl ether (9), tagitinin F-3-O-methyl ether (10), tagitinin F (11), tagitinin A (12), 3β-acetoxy-4α-hydroxyeduesm-11(13)-en-12-oic acid (13) and ilicic acid (14) were isolated from the aerial parts of Tithonia diversifolia. Their structures were established by spectroscopic analysis, while the relative configuration of compound 1 was confirmed by X-ray diffraction analysis. In addition, compounds 1-14 were evaluated in vitro for their anti-hyperglycemic activity by glucose uptake in 3T3-L1 adipocytes. It was found that 10μg/mL 1, 3, 6 and 8 could significantly increase glucose uptake without significant toxic effects.

Two New Phenolic Glycosides from Gnaphalium affine D. Don and Their Anti-Complementary Activity

Two new phenolic glycosides, named gnaphaffine A and B (compounds 1 and 2), were isolated from Gnaphalium affine. together with six known compounds, including caffeic acid (3), everlastoside L (4), isorhamnetin-7-O-β-d-glucopyranoside (5), quercetin-3-O-β-d-glucopyranoside (6), scutellarein-7-O-β-d-glucoside (7) and api-genin-7-O-β-d-glucopyranoside (8). Their structures were elucidated by spectroscopic methods, including ESI-MS and 2D NMR spectroscopy (HMQC and HMBC). All compounds were evaluated for their anti-complementary activity on the classical pathway of the complement system in vitro.

Sesquiterpenoid Glycosides from the Fruits of Chaenomeles speciosa

A new sesquiterpenoid glycoside, called speciosaoside A (1), and a known sesquiterpenoid glycoside, (1′R,3′R,5′R,8′S)-epi-dihydrophaseic acid β-D-glucoside (2), were isolated from the fruits of Chaenomeles speciosa (Sweet) Nakai (Rosaceae) using column chromatography and preparative HPLC. The structure of compound1was deduced from comprehensive spectroscopic analysis including IR, HR-ESI-MS, 1D NMR, and 2D NMR. The structure of compound2was identified by comparison of its spectral data with those reported in the literature.