Chemistry, antioxidant and antimicrobial potentials of white pepper (piper nigrum l.) essential oil and oleoresins

Abstract

The antioxidant and antimicrobial potentials of volatile oil and oleoresins of white pepper (Piper nigrum L.) was investigated in the present study. The white pepper essential oil has shown strong activity for the inhibition of primary and secondary oxidation products in mustard oil added at 0.02 % concentration which was evaluated using peroxide value and thiobarbituric acid value. Moreover it was further supported by complementary antioxidant assays such as ferric thiocyanate method in linoleic acid system, chelating and scavenging effects on 1,10-diphenyl- 2-picrylhydrazyl radical. In antimicrobial investigations, using inverted petriplate and food poison techniques, white pepper essential oil showed strong inhibition for Fusarium graminearum and Penicillium viridicatum. The white pepper ethanol and n-hexane oleoresin showed moderate inhibition for all tested fungal strains. Gas chromatography?Mass spectrometry (GC?MS) technique was used to analyze 40 different components constituting approximately 97.7 % of the volatile oil. Among them b-caryophyllene (16.0 %), sabinene (12.6 %), limonene (11.9 %) and torreyol (9.3 %) were the major components with many minor components. Both ethanol and n-hexane oleoresins comprise of 26 components having piperine, as the major component.