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Introduction: Gingers, belonging to the family Zingiberaceae, are popularly known for their beneficial uses in medicine and culinary applications. Aim: This study was conducted to evaluate the DPPH radical scavenging activity of the leaves and rhizomes of Zingiber officinale Rosc., Curcuma longa L., and Etlingera elatior (Jack) R.M. Smith. Methods: The plant samples were collected from Bukidnon, Mindanao, Philippines. Both water and ethanolic extracts were prepared separately from its leaves and rhizomes. The extracts were subjected to the determination of DPPH radical scavenging activity relative to ascorbic acid. Results and Discussion: Leaves, in general, had higher radical scavenging activity in water than in ethanol extracts. On the other hand, rhizomes had generally higher radical scavenging activity in ethanol than in water extracts except for E. elatior. Among the leaf extracts, E. elatior possessed the highest radical scavenging activity. In both water and ethanol, E. elatior displayed higher radical scavenging activity in its leaves that its rhizomes. Conclusion: Findings of this study suggest the potential of E. elatior leaves as source of antioxidants.

Introduction: Zingiberaceae rhizomes are commonly investigated due to its applications in food and traditional medicine use. However, less scientific attention was given to its leaves. Aim: This study primarily aimed to compare the antioxidant activity of the leaves and rhizomes of common Zingiberaceae plants namely: Zingiber officinale, Curcuma longa and Etlingera elatior. Methods: Antioxidant activity of the water and ethanol extracts of the leaves and rhizomes of the studied plants was determined using cyclic voltammetry (CV) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. Results: Very low positive correlation (r = 0.22) of antioxidant activities was observed between DPPH and CV methods. In both DPPH and CV methods, E. elatior has generally higher antioxidant activity in leaves than in rhizomes and water extract than ethanol extracts. Higher antioxidant activity was observed in leaves than in rhizomes for Z. officinale and C. longa for both water and ethanol extracts. In general, water extracts of the three ginger plants have higher antioxidant activity than its ethanol extracts. Conclusion: Both CV and DPPH assay revealed that leaves of common gingers studied are potential sources of antioxidants.