Chemical Analysis, Antimicrobial and Antioxidant Activities of Harsingar (Nyctanthes arbortristis) essential oil

Abstract

The present investigation deal with study of chemical composition of Harsingar (Nyctanthes arbortristis) essential oil from leaves antimicrobial and antioxidant potential of essential oil, major compound eugenol and its derivatives. The essential oil was extracted through hydro-distillation using Clevenger apparatus. Gas chromatography-Mass spectrometry analysis of essential oil revealed the presence of eugenol (88.20 %) as major compound which was isolated from essential oil by column chromatography. It was chemically transformed into two derivatives i.e. eugenol -5- aldehyde (2) and 5-allyl-2-hydroxy-3-methoxybenzenesulfonic acid (3). The essential oil, eugenol and its derivatives were evaluated for their antimicrobial activity against Klebsiella pneumoniae and Pseudomonas aeruginosa by disc plate method and against Fusarium oxysporum using agar well diffusion method. They were also evaluated for their antioxidant potential by 2, 2-diphenyl-1- picrylhydrazyl (DPPH) and NO free radical scavenging activities. The essential oil showed maximum antibacterial potential with diameter of inhibition zone of 23.8 and 26.3 mm at 1000 μg/ml against K. pneumoniae and P. aeruginosa respectively. 5-allyl-2-hydroxy-3-methoxybenzenesulfonic acid (3) was most effective against F. oxysporum with maximum diameter of inhibition zone of 29.5 mm at 2500 μg/ml. Eugenol (1) showed maximum antioxidant potential with 90.77 and 88.99 % radical scavenging in DPPH and NO radical scavenging assays having IC50 values of 18.07 and 26.50 μg/ml respectively. Harsingar essential oil, eugenol and its derivatives may be used as promising antimicrobial and antioxidising agents and will help in the development of natural antimicrobials and antioxidants as substitute for their synthetic analogues.