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

alpha-Glucosidase plays a role in hydrolyzing complex carbohydrates into glucose, which is easily absorbed, causing postprandial hyperglycemia. Inhibition of oc-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 alpha-glucosidase inhibition (IC50s of 21.2 and 34.8 mu M, 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 mu g/mL. The MIC value of compound 1 against S. aureus was 13.32 mu M. An in silico molecular docking model suggested that both compounds are potent inhibitors of enzyme alpha-glucosidase and are therefore leading candidates as therapies for diabetes mellitus.

Automated summary

The novel compound schomburgkianone I and the reported compound guttiferone K exhibited potent inhibition against alpha-glucosidase and showed strong antibacterial activity. These compounds are potential candidates for diabetes treatment.