α-Glucosidase Inhibitory and Antimicrobial Benzoylphloroglucinols from Garcinia schomburgakiana Fruits: In Vitro and In Silico Studies.

α-Glucosidase plays a role in hydrolyzing complex carbohydrates into glucose, which is easily absorbed, causing postprandial hyperglycemia. Inhibition of α-glucosidase is therefore an ideal approach to preventing this condition. A novel polyprenylated benzoylphloroglucinol, which we named schomburgkianone I (1), was isolated from the fruit of Garcinia schomburgkiana, along with an already-reported compound, guttiferone K (2). The structures of the two compounds were determined using NMR and HRESIMS analysis, and comparisons were made with previous studies. Compounds 1 and 2 exhibited potent α-glucosidase inhibition (IC50s of 21.2 and 34.8 µM, respectively), outperforming the acarbose positive control. Compound 1 produced wide zones of inhibition against Staphylococcus aureus and Enterococcus faecium (of 21 and 20 mm, respectively), compared with the 19 and 20 mm zones of compound 2, at a concentration of 50 µg/mL. The MIC value of compound 1 against S. aureus was 13.32 µM. An in silico molecular docking model suggested that both compounds are potent inhibitors of enzyme α-glucosidase and are therefore leading candidates as therapies for diabetes mellitus.

Anti-inflammatory effect of a triterpenoid from Balanophora laxiflora: results of bioactivity-guided isolation.

Balanophora laxiflora, a medicinal plant traditionally used to treat fever, pain, and inflammation in Vietnam, has been reported to possess prominent anti-inflammatory activity. This study examined the active constituents and molecular mechanisms underlying these anti-inflammatory effects using bioactivity-guided isolation in combination with cell-based assays and animal models of inflammation. Among the isolated compounds, the triterpenoid (21α)-22-hydroxyhopan-3-one (1) showed the most potent inhibitory effect on COX-2 expression in LPS-stimulated Raw 264.7 macrophages. Furthermore, 1 suppressed the expression of the inflammatory mediators iNOS, IL-1ß, INFß, and TNFα in activated Raw 264.7 macrophages and alleviated the inflammatory response in carrageenan-induced paw oedema and a cotton pellet-induced granuloma model. Mechanistically, the anti-inflammatory effects of 1 were mediated via decreasing cellular reactive oxygen species (ROS) levels by inhibiting NADPH oxidases (NOXs) and free radical scavenging activities. By downregulating ROS signalling, 1 reduced the activation of MAPK signalling pathways, leading to decreased AP-1-dependent transcription of inflammatory mediators. These findings shed light on the chemical constituents that contribute to the anti-inflammatory actions of B. laxiflora and suggest that 1 is a promising candidate for treating inflammation-related diseases.