PRELIMINARY PHYTOCHEMICAL SCREENING AND IN VITRO ANTIOXIDANT POTENTIAL OF AQUEOUS, HYDRO-METHANOLIC AND HYDRO-ETHANOLIC EXTRACTS OF ZINGIBER OFFICINALE ROSCOE: A COMPARATIVE ANALYSIS BETWEEN NIGERIAN AND INDIAN VARIETY

Ginger (Zingiber officinale Roscoe) is a herb that is well known and widely used, especially in Asia and Africa, which contains several interesting bioactive constituents and possesses health promoting properties. In this study, Phytochemical contents and antioxidant potential of Nigerian and Indian ginger were assessed in an effort to compare and validate the medicinal potential of the plant. Aqueous, hydro-methanolic and hydro-ethanolic extracts of Indian and Nigerian varieties were prepared by extraction process. Both varieties were found to contain high amount of secondary metabolites with exception of phlobotannins which happened to be in low quantity and tannins which is entirely absent in all the extracts. DPPH scavenging activity, Hydrogen peroxide and reducing power were assayed. The comparison carried out between different extracts of the two varieties using t-test at P=0.05 revealed a significant difference in terms of antioxidant activity. Indian variety was generally found to have more antioxidant activity than the Indian one with the exception of aqueous extract of Nigerian variety. This is probably due to high level of phenolics and flavonoids in the Indian variety. This study validated the medicinal potential of Zingiber officinale and established some relationship between the two varieties in terms of their antioxidant properties.