Polyphenolic characteristics, antimicrobial and antioxidant activity of Zingiber neesanum (Graham) Ramamoorthy rhizomes and identification of volatile metabolites by GC-MS analysis
Rhizomes of Zingiber neesanum (Graham) Ramamoorthy, endemic to Western Ghats and subject to few studies, were analysed for bioactivity and phytochemical composition. High total tannin (TT) content in isopropanol extract [55.261 ± 6.623 mg TAE.100 g–1 DW] contributed to antimicrobial activity against gram negative Enterococcus fecalis (21.7 ± 0.6 cm) while high total flavonoid (TF) content in ethyl acetate extract [681.94 ± 33.87 mg CE.100 g−1 DW] accounted for the antifungal activity against Mucor rouxii (9.7 ± 0.6). Isopropanol extracts also showed high anti-oxidant activity as determined by DPPH and FRAP assays. Major bioactive phytochemical constituents in Z. neesanum rhizome identified by GC-MS analysis included 2-Methyl-7-nonadecene (13.99%; antimicrobial), Actinomycin C2 (8.57%; antineoplastic) and Deoxyspergualin (12.55%; immunosuppressive).
