WenYi Jin

Triterpenoids and diarylheptanoids from Alnus hirsuta inhibit HIF-1 in AGS cells.

Bioassay-guided fractionation and purification of the EtOAc soluble fraction from the MeOH extract of the stem bark of Alnus hirsuta (Betulaceae), using an in vitro HIF-1 assay, led to the isolation of four triterpenoids (1–4) and six diarylheptanoids (5–10). Their structures were determined by comparison with the physicochemical and spectroscopic data in the literature. These compounds were investigated for their effects on the hypoxia-induced HIF-1 activation using an HIF-1 a mediated reporter gene assay in AGS cells. Among them, two diarylheptanoids, 2-oxatrycyclo[13.2.2.13,7]eicosa-3,5,7(20),15,17,18-hexaen-10-16-diol (6) and 2-oxatrycyclo [13.2.2.13,7]eicosa-3,5,7-(20), 15, 17, 18-hexaen-10-one (7), inhibited HIF-1 activation dose-dependently with IC50 values of 11.2 μM and 12.3 μM, respectively. These two compounds had no significant cytotoxicity to the AGS cells at the effective concentration for the inhibition of HIF-1 activation.

Inhibitory effect on TNF-α-induced IL-8 production in the HT29 cell of constituents from the leaf and stem ofWeigela subsessilis

Twelve compounds were isolated from the MeOH extract of the leaf and stem of the Korean endemic plantWeigela subsessilis L. H. Bailey. Their chemical structures were elucidated on the basis of physicochemical and spectroscopic data and by comparison with those of published literatures. These compounds were identified as three sterols, β-sitosterol acetate (2), β-sitosterol (3), daucosterol (11), eight triterpenoids, squalene (1), ursolic acid (4), ilekudinol A (5), corosolic acid (6), ilekudinol B (7), esculentic acid (8), pomolic acid (9), asiatic acid (10), and one iridoid glycoside, alboside I (12). This is the first report pertaining to the isolation of these compounds fromWeigela subsessilis L. H. Bailey. In addition, three compounds7, 9, and12 were found to display a strong inhibitory effect on the production of IL-8 in the HT29 cells stimulated by TNF-α.

Flavonoids and Isoflavonoids from Sophorae Flos Improve Glucose Uptake in Vitro

Glucose uptake assay-guided fractionations on the methanol extract of Sophorae Flos led to the isolation of the flavonoids rutin (1), narcissin (2), quercetin (3), tamarixetin (4), and kaempferol (5) and the isoflavonoids cajanin (6), genistein (7), orobol (8), and pratensein (9). Among them, 1, 4, 5, 6, 8, and 9 significantly improved basal glucose uptake in HepG2 cells. Their improving effects were concentration dependent. Compounds 4, 5, 6, and 9 exhibited effects stronger than that of rosiglitazone, which has been used as an antidiabetic drug. However, 2, 3, and 7 did not show any improving effects. Stimulating glucose uptake into peripheral cells may be responsible for reducing the level of blood glucose in the circulation. Therefore, these findings demonstrate a potential to develop these flavonoids and isoflavonoids as hypoglycemic drugs.

Antioxidant activity of cleomiscosins A and C isolated from Acer okamotoanum

Phytochemical investigation ofAcer okamotoanum leaf and twig led to the isolation of two cou-marinolignans, cleomiscosin A (1) and cleomiscosin C (2). Here, we found that2 dose-depen-dently inhibits LDL oxidation mediated by either catalytic copper ions (Cu2+) or free radicals generated with the azo compound 2,2’-azobis-(2-amidinopropane)dihydro-chloride (AAPH) with lC50s of 29.5 and 11.9 μM, respectively. By electrophoretic analysis, we also observed that 2 protects apolipoprotein B-100 (apoB-100) against Cu2+-induced fragmentation (65.3% inhibition at 5 μM). Furthermore, fluorescence analyses clearly indicated that both 1 and 2 protect against the oxidative modification of apoB-100 induced by either Cu2+ or HOCl (1, lC50s of 13.4 and 8.1 μM, respectively;2, lC50s of 23.6 and 3.9 μM. respectively). These findings suggest that 1 and 2 could be beneficial in preventing LDL oxidation in atherosclerotic lesions.

Isolation of constituents and anti-complement activity fromAcer okamotoanum

A novel acylated sterol glucoside (1) along with four known compounds, β-amyrin acetate (2), 3β,24-dihydroxytaraxer-14-ene (3), cleomiscosin A (4), and deomiscosin C (5), were isolated from the leaf and twig ofAcer okamotoanum Nakai (Aceraceae). The structure of the new compound was determined to be β-sitosterol glucoside-3’-0-hexacosanoicate based on chemical and spectroscopic analyses. In addition, the novel compound was found to exhibit a significant inhibitory effect (IC50 value of 0.2 (μM) on the complement system activated by the classical pathway.