The effect of microwave power and feed to solvent ratio on antioxidant activity and volatile compounds profile of crystal seedless guava leaves essential oils extracted using microwave-assisted hydrodistillation

Abstract

This work utilized by-product of crystal seedless guava leaves due to its cultivation for commercial fruit production persuaded to prune guava trees branches. Essential oil (EO) extracted from plant biomass is a source of natural antioxidants due to the presence of essential components. This study was outlined to explore the potential of antioxidants and identify the chemical composition of EO extracted from crystal seedless guava using Microwave-assisted hydrodistillation (MAHD). The essential oils (EOs) were extracted using various microwave powers and feed to solvent (F/S) ratios. The two independent variables showed significantly affect on IC50 value of EOs, thereby there were several various IC50 values in DPPH free radical scavenging assay from EOs depends on their extraction condition. The best condition resulting in IC50 of EO was as low as 36.23 ± 2.07 µg/mL with a microwave power of 600 W and F/S ratio of 1:7 (w/v). The five major constituents of EO from the best extraction condition were caryophyllene (44.98%), caryophyllene oxide (14.96%), trans-nerolidol (9.16%), humulene (5.10%), and aromandendrene (5.10%). The study concluded that MAHD method possessed significant change in antioxidant activity and volatile compounds of EO extracted from crystal guava leaves.