Chemical Composition of Yemeni Medicinal Plants Essentials Oils and Their Antibacterial and Antioxidant Activities

Abstract

Medicinal plants have been used since time immemorial to fight against diseases. The biological activities of these plants may be due to the presence of bioactive compounds such as essential oils. The aim of this study was to determine the chemical composition of three Yemen medicinal plants, and e evaluate their antibacterial and antioxidant activities. The chemical composition of essential oils was determined using gas chromatography–mass spectrometry (GC–MS) analysis. The antibacterial effect was evaluated against pathogenic bacterial strains using the micro-platoon method and the antioxidant activity was estimated by DPPH (2,2-diphenyl-1-picrylhydrazyl) scanning radical assay. Essential oils (EOs) are rich in phenolic compound. Carvotanacetone is the main compound of Pulicaria jaubertii (PJ) essential oil (82.35%) and β-maaliene (64.94%) is the major compound of Plectranthus montanus Benth (PMB) essential oil, while, Tarchonanthus camphoratus (TC) essential oil possesses several main compounds such as fenchol (14.5%), α-pinene (12.43%), and α-terpineol (8.58%). Essential oils of PJ and PMB showed remarkable antibacterial effect against Staphylococcus aureus (minimum inhibitory concentration, MIC = 0.25% [v/v]), and PJEO against Escherichia coli (MIC = 0.25%[v/v]); the lowestMBC (minimum bactericidal concentration) values was obtained with PJEO against Staphylococcus aureus (CMI = 0.25% [v/v]). TCEO interestingly showed capacity while scanning the DPPH radical (6.32 mg E Trolox). These findings showed the biological potential of Yemeni aromatic medicinal plants as antibacterial and antioxidant agents. However, further investigations are needed to determine the antibacterial and antioxidant mechanisms of these oils.