Phenolics and Bioactivities of Symplocos cochinchinensis Leaf Extracts Obtained by Conventional Solvent, Enzyme and Ultrasound Assisted Extractions

Abstract

Symplocos cochinchinensis (Lour.) Moore ssp. laurina (Retz) Noot. has been commonly used in traditional medicine to treat different ailments in many Asian countries. This study aimed to compare phenolics, antioxidant activity, and inhibitory effects on a-amylase, a-glucosidase, and albumin denaturation of S. cochinchinensis leaf extracts obtained by different extraction methods. 9 phenolics in the extracts were quantified and the results showed the 50% methanol extract contained the greatest sum of phenolics (193.72 mg/g) compared to the others. The 50% acetone extract exhibited the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity (IC50= 183.88 mg/mL) while the 50% ethanol extract showed the most potent activity predicted by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) assay (IC50= 365.05 mg/mL). In general, all the S. cochinchinensis leaf extracts had comparatively low inhibitory effects on a-amylase and a-glucosidase compared to acarbose used as a reference standard. The ethanol extract presented the lowest IC50 values (184.49 mg/mL), indicating the strongest protection of albumin from denaturation. The results also the applications of enzyme and ultrasound to extraction of S. cochinchinensis leaves proved effective in extracting phenolics. The findings of the study provide a better understanding of phytochemicals and potential health benefits of S. cochinchinensis leaves, which is useful for development of new naturally occurring agents for disease prevention and treatment.

Keywords

• antidiabetic
• anti-inflammatory
• antioxidant activity
• phenolics
• symplocos cochinchinensis