Antioxidant Activity and Phenolic Content of Hornstedtia conoidea (Zingiberaceae)

Introduction: Several Zingiberaceae plants were reported to possess wide range of antioxidants. The Philippine endemic Hornstedtia conoidea is still poorly investigated. Aim: This study aimed to provide fundamental information on the total antioxidant activity and total phenolic content of the methanolic extracts of the leaves and rhizomes of H. conoidea. Methods: The leaves and rhizomes of H. conoidea were collected from Kibawe, Bukidnon, Philippines, oven-dried at 40°C and extracted using absolute methanol. The total antioxidant activity and total phenolic content of the methanolic extracts of the leaves and rhizomes of H. conoidea were evaluated through Phosphomolybdenum method and Folin- Ciocalteu method, respectively. Results: The total antioxidant activity, expressed as milligram ascorbic acid equivalent per gram sample, was significantly higher in leaves (4.67) as compared to rhizomes (2.03). Furthermore, the determination of total phenolic content, expressed as milligram gallic acid equivalent per gram sample, revealed that leaves have greater amount of phenolics (1.67) than rhizomes (1.28). A positive correlation between total antioxidant activity and total phenolic content was observed. The present findings support that the leaves and rhizomes of H. conoidea are both potential sources of natural antioxidants.