Antioxidant activity, total phenolic, total flavonoid and vitamin C contents of Hornstedtia havilandii (K. Schum.) K. Schum. from Sabah

Hornstedtia is a genus within the Zingiberaceae family, known for its therapeutic properties. However, Hornstedtia havilandii, native to Sabah, has received comparatively limited research attention. Therefore, this study aims to conduct phytochemical evaluation and antioxidant activity of H. havilandii from Sabah. In this study, water was employed as a solvent, and the maceration method was employed to extract the bioactive compounds from the dried fruits, leaves, and stems of H. havilandii. The total flavonoid content (TFC), total phenolic content (TPC), and vitamin C content were quantified using calibration standard curves ranging from 5 to 160 mg/mL and colorimetric titration method respectively. Antioxidant activity expressed as IC50, was determined by conducting diphenyl-2-picrylhydrazyl (DPPH) scavenging assay. The maceration of extract revealed the highest yield in fruits at 10.87%, followed by leaves at 9.03% and stems at 7.98%. Notably, the aqueous fruit extract exhibited significant antioxidant activity with an IC50 of 3.31 ± 0.09 µg/mL, surpassing the aqueous leaves extract at IC50 of 16.86 ± 0.27 µg/mL and showing lower activity in the aqueous stem extract with IC50 of 310.46 ± 0.27 µg/mL. Due to the notable antioxidant activity in the fruit extracts, further quantification of TPC and TFC of the aqueous fruit extract was conducted. The TPC of the fruit extract is 16.17 ± 0.00120 mgGAE/g, and the TFC is 8.54 ± 0.00137 mgRE/g. Given the importance of vitamin C as a nutrient influencing antioxidant activity, quantification revealed that the aqueous fruit extract contained 162.47 ± 0.70 mg/100mL of vitamin C. These findings indicate that H. havilandii holds untapped potential as a locally available and cost-effective source of the natural antioxidant agent. Nonetheless, further research is warranted to identify additional natural components and assess their overall efficacy as natural antioxidants.