Comprehensive GC-MS and FT-IR Profiling of Coleus zeylanicus essential oil and investigation of its anti-fungal and anti - oxidant activities

Abstract

To evaluate the leaf volatile constituents of essential oil of Coleus zeylanicus and evaluate their anti-oxidant and anti-fungal activity. The Chemical composition of Coleus zeylanicus essential oil was determined using GC-MS and FT-IR analytical techniques. The antioxidant activity was evaluated using DPPH scavenging assay. The anti-fungal effect was tested against two potential pathogenic fungal strains - Candida albicans and Malassezia furfur using agar well diffusion method. The essential oil was profiled by the presence of sesquiterpene hydrocarbons 90.67% of their total composition followed by oxygenated monoterpenes and monoterpene hydrocarbons as 5.3% and 2.1% respectively. The GC-MS results showed 14 compounds from Coleus zeylanicus leaf EO representing 98.07% of the total oil composition. The major component was identified as a-Gurjunene (35.94%), a-bisabolol (10.82%) and G-selinene (4.26%). EO showed remarkable antioxidant activity values of IC50 = 59.78± 3.21µg/ml by DPPH scavenging assay. The essential oil showed interesting anti-fungal effects against two pathogenic fungal strains. The most sensible strains to Coleus zeylanicus EO was Malassezia furfur (32.00±0.50mm) compared to that of Candida albicans (15.00±1.25mm). Hence, Coleus zeylanicus EO has potential application against fungal infection and oxidative stress-related diseases. However, further investigations are necessary to isolate and investigate the action mechanism of these bioactive compounds.