Comparative and correlation studies of garcinol content with In vitro alpha-amylase inhibitory activity, and antioxidant properties of fruits, leaves and bark extracts from two Sri Lankan endemic Garcinia species: Garcinia quaesita and Garcinia zeylanica

Garcinia quaesita and Garcinia zeylanica are two endemic Sri Lankan species used as sour flavoring agents and in Ayurvedic treatments. This study compares fruits, leaves, and bark extracts, and a correlation analysis linking garcinol content with antioxidant activity and alpha-amylase inhibition. Garcinol is a key bioactive compound, was highest in the hexane extracts of the fruits and bark of G. quaesita and in the fruits of G. zeylanica, highlighting nonpolar solvents are most effective. These extracts exhibited strong antioxidant activity, positively correlating with garcinol content. Despite low garcinol content in methanolic bark extracts, both species showed antioxidant and alpha-amylase inhibitory activities.