Influence of seasonal harvesting on the chemical profile, antioxidant and antimicrobial properties of Murraya koenigii (L.) spreng leaf essential oil

Abstract

The present study investigates variations in the antioxidant, antimicrobial, and chemical profile of essential oil extracted from Murraya koenigii (L.) Spreng leaves during spring and autumn. Higher oil content was obtained in autumn (0.94%) compared to that collected in spring (0.73%). Sabinene was determined to be major ( 24.44% and 29.14%) compound in both samples, followed by α-pinene, β-Caryophyllene, DL-limonene, γ-terpinene. Hierarchical cluster analysis of thirty-three different M. koenigii essential oil samples (including two from the present study and 31 from the literature) led to unique chemotypic groups. Antimicrobial studies showed higher inhibitory potential during the autumn season; greater inhibition was observed against both Staphylococcus aureus and MRSA (MIC = 0.50 mg/ml) and Aspergillus flavus (74.4% by 10mg/ml). IC₅₀ values together with enhanced radical scavenging activity indicate the potent antioxidant nature of autumn-extracted essential oil. The results validate M. koenigii leaf essential oil as a promising antimicrobial and antioxidant agent.