Purified Gymnemic Acids from Gymnema inodorum Tea Inhibit 3T3-L1 Cell Differentiation into Adipocytes.

Gymnema inodorum (GI) is an indigenous medicinal plant and functional food in Thailand that has recently helped to reduce plasma glucose levels in healthy humans. It is renowned for the medicinal properties of gymnemic acid and its ability to suppress glucose absorption. However, the effects of gymnemic acids on adipogenesis that contribute to the accumulation of adipose tissues associated with obesity remain unknown. The present study aimed to determine the effects of gymnemic acids derived from GI tea on adipogenesis. We purified and identified GiA-7 and stephanosides C and B from GI tea that inhibited adipocyte differentiation in 3T3-L1 cells. These compounds also suppressed the expression of peroxisome proliferator-activated receptor gamma (Pparγ)-dependent genes, indicating that they inhibit lipid accumulation and the early stage of 3T3-L1 preadipocyte differentiation. Only GiA-7 induced the expression of uncoupling protein 1 (Ucp1) and pparγ coactivator 1 alpha (Pgc1α), suggesting that GiA-7 induces mitochondrial activity and beige-like adipocytes. This is the first finding of stephanosides C and B in Gymnema inodorum. Our results suggested that GiA-7 and stephanosides C and B from GI tea could help to prevent obesity.

Determination of Free Radical Scavenging, Antioxidative DNA Damage Activities and Phytochemical Components of Active Fractions from Lansium domesticum Corr. Fruit.

Lansium domesticum Corr. or "long-kong" is one of the most popular fruits in Thailand. Its peel (skin, SK) and seeds (SD) become waste unless recycled or applied for use. This study was undertaken to determine the bioactivity and phytochemical components of L. domesticum (LD) skin and seed extracts. Following various extraction and fractionation procedures, 12 fractions were obtained. All fractions were tested for antioxidant capacity against O2(-•) and OH(•). It was found that the peel of L. domesticum fruits exhibited higher O2(-•) and OH(•) scavenging activity than seeds. High potential antioxidant activity was found in two fractions of 50% ethanol extract of peel followed by ethyl acetate (EA) fractionation (LDSK50-EA) and its aqueous phase (LDSK50-H2O). Therefore, these two active fractions were selected for further studies on their antioxidative activity against DNA damage by hydrogen peroxide (H2O2) in human TK6 cells using comet assay. The comet results revealed DNA-protective activity of both LDSK50-EA and LDSK50-H2O fractions when TK6 human lymphoblast cells were pre-treated at 25, 50, 100, and 200 µg/mL for 24 h prior to H2O2 exposure. The phytochemical analysis illustrated the presence of phenolic substances, mainly scopoletin, rutin, and chlorogenic acid, in these two active fractions. This study generates new information on the biological activity of L. domesticum. It will promote and strengthen the utilization of L. domesticum by-products.

Antimutagenicity and antioxidative DNA damage properties of oligomeric proanthocyanidins from Thai grape seeds in TK6 cells.

Oligomeric proanthocyanidins (OPCs) are found mostly in red grape seeds. Many publications have reported that OPCs possess an excellent anti-oxidant effects. Since it could against cellular damage from reactive oxygen species (ROS) led to reduce the risk of chronic disease and cancers. We carried out this study on the Thai OPCs to evaluate the mutagenicity/ anti-mutagenicity and anti-oxidative DNA damage effects in TK6 cells by micronucleus (MN) and comet assays. In the MN assay, OPCs-treatment of TK6 cells at concentrations ranging from 10-200 ?g/ml (4 and 24 h) did not cause micronucleus induction over the negative control group but revealed a significant reduction the micronucleus frequencies against the known mutagen (mitomycin C). In the comet assay, OPCs-treated TK6 cells at concentrations of 100, 250, 500, and 1,000 ?g/ml could inhibit DNA damage induced by H(2)O(2) as indicated by 18.7, 36.4, 30.6, and 60.1%, respectively. Our results suggest that OPCs possess the anti-mutagenic and anti-oxidative DNA damage effects in TK6 cells under the conditions of this assay.