In vitro and in vivo antioxidant and antihyperglycemic potentials of phenolic fractions of Syzygium zeylanicum (L.) DC trunk‐bark

Syzygium zeylanicum L. (DC) (SZL) has been used in antidiabetes treatment for ages. However, the scientific evidence of active agents that have antidiabetic activity and response against biological activities is limited. In this study, the active components of SZL trunk‐bark extract (SZL extract) were identified using principal component analysis (PCA), and their antidiabetic activities were assessed. The results indicated that the ethyl acetate fraction (EAF) had the highest concentration of phenolic compounds, antioxidants, and antihyperglycemic activities in the postprandial zebrafish model. The major antioxidant contributors were gallic acid, catechin, epicatechin, ellagic acid, quercetin, caffeine, and apigenin, and their concentrated levels reduced α‐amylase inhibitory activity, whereas rutin and ethyl gallate influenced the α‐glucosidase inhibitory activity. This study showed the bio‐functional properties of active phenolic compounds present in the SZL extract, potentially serving as a functional food to control hyperglycemia.