Extraction, chemical composition, and antioxidant activity analysis of essential oil from Schinus molle medicinal plant found in Botswana

Abstract

The aim of this study was to investigate the effects of hydro distillation (HD) and ultrasonic-assisted hydro distillation (UAHD) on the yield, chemical composition and antioxidant activity of the essential oils extracted from Schinus molle plants cultivated in Botswana. Hydro distillation with a Clevenger apparatus and ultrasonic-assisted hydro distillation at 300 W and 50 W were used as the extraction methods of choice to extract the essential oil from the plant leaves. The average percentage yield of essential oil obtained by HD was 1.91 ±0.27%, while that obtained by UAHD at 300 W was 2.33 ± 0.21%and UAHD at 50 W was 1.14 ± 0.11%. Major compounds found in the essential oil extracted by HD were limonene (13.93%), elemol (12.35%), α-phellandrene (10.82%), aromadendrene (9.11%), 6-epi-shyobunol (6.75%), α-eudesmol (5.14%), β- cadinene (4.61%), and α-muurolene (4.29%). Major compound identified in the essential oil extracted by UAHD (at 300 W and 50 W) were as follows: elemol (15.23%, 24.04%), 6-epi-shyobunol (12.39%, 12.32%), aromadendrene (9.92%, 9.81%), and α-eudesmol (9.74%, 8.37%). The antioxidant activity test was performed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The IC50 of essential oil obtained by HD was 134.3 µg/ml, while the essential oil extracted by UAHD at 300 W had IC50 of 102.3 µg/ml, and that of UAHD at 50 W was 226.0 µg/ml. It is worth noting that this is the first time that this study was done for this plant species cultivated in Botswana.