α-mangostin improves glucose uptake and inhibits adipocytes differentiation in 3T3-L1 cells via PPARgamma, GLUT4, and leptin expressions

Obesity has been often associated with the occurrence of cardiovascular diseases, type 2 diabetes, and cancer. The development of obesity is also accompanied by significant differentiation of preadipocytes into adipocytes. In this study, we investigated the activity of α-mangostin, a major xanthone component isolated from the stem bark of G. malaccensis, on glucose uptake and adipocyte differentiation of 3T3-L1 cells focusing on PPARγ, GLUT4, and leptin expressions. α-Mangostin was found to inhibit cytoplasmic lipid accumulation and adipogenic differentiation. Cells treated with 50 μM of α-mangostin reduced intracellular fat accumulation dose-dependently up to 44.4% relative to MDI-treated cells. Analyses of 2-deoxy-D-[3H] glucose uptake activity showed that α-mangostin significantly improved the glucose uptake ( P < 0.05 ) with highest activity found at 25 μM. In addition, α-mangostin increased the amount of free fatty acids (FFA) released. The highest glycerol release level was observed at 50 μM of α-mangostin. qRT-PCR analysis showed reduced lipid accumulation via inhibition of PPARγ gene expression. Induction of glucose uptake and free fatty acid release by α-mangostin were accompanied by increasing mRNA expression of GLUT4 and leptin. These evidences propose that α-mangostin might be possible candidate for the effective management of obesity in future

Antioxidant and antimicrobial activities of shorea kunstleri

Objective: To evaluate antioxidant and antimicrobial activities of stembark of Shorea kunstleri together with analysis of phytochemical and total phenolic contents. Methods: Extraction was conducted with different solvent polarity of n-hexane, dichloromethane (DCM) and methanol by using Soxhlet extraction. Total phenolic content was determined using Folin-Ciocalteu method. Free radical scavenging activity and inhibition of lipid peroxidation were evaluated with DPPH radical scavenging and ferric thiocyanate (FTC) assays, respectively. Antimicrobial activities were performed using disc diffusion method, minimum inhibition concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC). Results: S. kunstleri stembark extracts revealed presence of steroids, terpenoids, saponins, flavonoids, and phenolic compounds. Methanol extract exhibited the highest total phenolic content and free radical scavenging activity result in phenolic content of 8.34±0.003 g GAE/100 g of extract and 95.9±1.07% DPPH inhibition (IC50 value of 18.6 µg/ml), respectively. FTC assay of n-hexane, DCM, and methanol extracts indicated lipid peroxidation inhibitory activity of 74.2±0.35%, 74.0±0.10%, and 72.8±0.27%, respectively. In antimicrobial and antifungal tests, methanol extract showed inhibition against S. aureus, C. albicans, and C. tropicalis with inhibition zones of 10-12, 18-22, and 18-19 mm, respectively. The MIC test of methanol extract showed highest inhibition against C. albicans and S. aureus (0.04 and 0.08 mg/ml, respectively) while DCM extract exhibited the highest activity towards C. tropicalis (MIC value of 0.63 mg/ml). Taken together, MBC test of methanol extract strongly demonstrated bactericidal effect against S. aureus with MBC value of 0.08 mg/ml. Conclusion: The study demonstrated that stembark extracts of S. kunstleri possessed antioxidant and antimicrobial properties