Antimicrobial and antioxidant activities of extracts from medicinal plant ginger (Zingiber officinale) and identification of components by gas chromatography

The present study was conducted to investigate antioxidant and antimicrobial activities of Zingiber officinale, and detected possible chemicals existence in the plant. Phytochemical screening was carried out using the standard test methods of different chemical groups. Investigating the antioxidant activity, one complementary test method namely 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay was carried out. Disc diffusion method, with minor modifications was used for the evaluation of in vitro antimicrobial activity. The extracts were a rich source of phytochemicals. In DPPH free radical scavenging test, the ethanol, acetone and cyclohexane extracts show the highest free radical scavenging activities, although the extracts revealed good antimicrobial activities. Finally, the bioactive compounds of Zingiber officinale rhizomes have been evaluated by using GC-spectroscopy.   Key words: Zingiber officinale, GC spectroscopy antimicrobial, antioxidant, agar-well diffusion, phytochemical screening.