Extraction, chemical composition, and antioxidant activity analysis of essential oil from Schinus molle medicinal plant found in Botswana
Nicholas Phiri, Eniah Lemogang Serame, Tshepo Pheko-Ofitlhile
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.