Chemical Composition, Antioxidant and Antifungal Potential of Clove (Syzygium aromaticum) Essential Oil, its Major Compound and its Derivatives

Abstract

In this present study, clove essential oil was extracted through hydro distillation using Clevenger apparatus which revealed the presence of (%) moisture (29.47±0.08), ash (5.29±0.08), crude fat (5.86±0.03), crude fibre (14.37±0.04), crude protein (6.91±0.37) and total soluble sugars (32.10±0.05) content. Mineral analysis showed the presence of calcium (Ca), potassium (K), phosphorus (P), magnesium (Mg) and sodium (Na) in appreciable amount. GC/MS analysis of clove essential oil revealed the presence of twenty one compounds with eugenol (69.68 %) as major compound. Eugenol was isolated from clove essential oil by column chromatography. It was chemically transformed into two derivatives i.e. eugenol acetate and eugenol benzoate. Antifungal and antioxidant potential of clove essential oil, its major compound and its derivatives were tested against three pathogenic fungi (Fusarium moniliforme, Helminthosporium oryzae and Rhizoctonia solani) using poison food technique and 2,2-diphenyl-1-picryl hydrazyl (DPPH) and nitric oxide (NO) free radical scavenging assays respectively. Clove essential oil showed moderate antifungal potential against all the three test fungi. However eugenol benzoate was most effective against Fusarium moniliforme and Helminthosporium oryzae with ED50 values of 10.17 and 5.3 μg/ml respectively whereas in case of Rhizoctonia solani, eugenol acetate was most effective with ED50 value of 11.76 μg/ml. Clove essential oil showed maximum antioxidant potential with IC50 in the range of 10.87-31.63 μg/ml. Hence it was concluded that derivatives of eugenol isolated from clove essential oil showed maximum antifungal potential against the test fungi while antioxidant potential of clove essential oil was found to be maximum.