Effects of Solvent Type and Simplicia-to-Solvent Ratio on the Phenolics, Flavonoids, and Antioxidant Activity of Torch Ginger (Etlingera elatior) Fruit

Torch ginger (Etlingera elatior) is an aromatic plant commonly used as a spice in food. İt contains key phytochemicals such as phenolics, and flavonoids with potent antioxidant activity. This study aimed to investigate the effect of extraction condition (solvent type and Simplicia-to-Solvent ratio) on the total phenolic content, total flavonoid content, and antioxidant properties of torch ginger fruit (TFG). Nine different extracts combinations of TGF were obtained, with three solvents (70% ethanol, ethyl acetate, and n-hexane), and three powdered Simplicia-to-Solvent ratios (1:10, 1:20, and 1:30). The total phenolic, and total flavonoid contents of the different extracts were determined using standard procedures. The antioxidant activity was evaluated by the 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging assay. The results showed that ethanol extract at a Simplicia-to-Solvent ratio of 1:30 contained the highest total phenolic, and total flavonoid contents of 108.43 ± 2.33 mg GAE/g extract and 1.22 ± 0.08 mg QE/g extract, respectively. İn addition, the ethanol extract at a Simplicia-to-Solvent ratio of 1:30 exhibited the most potent antioxidant activity with IC50 of 76.157 ± 1.461 µg/mL. In conclusion, ethanol solvent at a Simplicia-to-Solvent ratio of 1:30 is the optimal extraction condition needed to achieve the highest total phenolic and flavonoid contents from TGF, while also providing the highest antioxidant activity.