Phenolics from the Rhizomes of Kaempferia galanga L. and Their Antioxidant Activity

Aims: This research aimed at exploring phenolics from the Kaempferia galanga L. and evaluating their antioxidant effect.

Research Design: Phenolics were isolated and identified from the rhizomes of Kaempferia galanga L. Their radical scavenging ability was assayed by using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay method.

Place and Duration of Study: Research was conducted at the School of Pharmacy, Guangdong Pharmaceutical University, between at October 2016 and December 2017.

Methodology: Phenolics were isolated and purified by silica gel, ODS middle pressure liquid chromatography (MPLC) and high-performance liquid chromatography (HPLC), identified utilizing 1D, 2D nuclear magnetic resonance (NMR) and mass spectrum (MS). The radical scavenging ability of the isolated compounds was investigated via DPPH method.

Results: Ten phenolics were isolated and identified from the rhizomes of Kaempferia galanga L. (1-10). All compounds exhibited different levels of antioxidant effects in radical scavenging. Among them, compound 2 exhibited pronounced inhibitory effects in DPPH radical scavenging assay.

Conclusion: In this study, ten phenolics were isolated from the rhizomes of sand ginger (Kaempferia galanga L.). DPPH radical scavenging was carried out to assess their antioxidant activity. The results indicated that some phenolics showed moderate antioxidant activity compared to those of ascorbic acid in DPPH. And these also demonstrated that phenolics may be partially responsible for the rhizomes of sand ginger’s antioxidant activity. The discovery of phenolics and their antioxidant bioactivities is beneficial for understanding the scientific basis of the effects of Kaempferia galanga L.