Phytochemical Profiling, Fourier Transform Infrared Spectroscopy (FTIR) Characterization, and Antioxidant Potential of Ethanol and Ethyl Acetate Leaf Extracts of Zingiber officinale

Abstract This study was done to investigate the phytochemical composition, FTIR analysis, and antioxidant properties of ethanol and ethyl acetate extracts of Zingiber officinale leaves. The powder leaf samples of Zingiber officinale was successively extracted by maceration using ethanol and ethyl acetate solvents. Standard methods were used to screen the plant for qualitative and quantitative phytochemicals compositions, and DPPH radical scavenging assay was used to determine the antioxidant activity, respectively. The qualitative phytochemical screening revealed the presence of alkaloids, flavonoids, phenolics, tannins, terpenoids, steroids, and glycosides in both extracts, while saponins were detected only in the ethanol extract. Quantitative analyses showed that the ethanol extract contained higher levels of flavonoids (23.88 mg GAE/g), phenolic compounds (47.16 mg/100 g), and tannins (10.50 mg/100 g) compared to the ethyl acetate extract. The FTIR analysis showed the presence of functional groups such as O–H, C–H, C=O, C=C, and C–O, supporting the occurrence of bioactive phytochemicals. The antioxidant activity demonstrated concentration-dependent inhibition, with the ethanol extract exhibiting stronger activity (IC50 = 78.63 µg/mL) than the ethyl acetate extract (IC50 = 83.15 µg/mL), though both were less potent than ascorbic acid (IC50 = 18.25 µg/mL). The findings indicate that solvent polarity influences phytochemical extraction and antioxidant capacity. In conclusion, Zingiber officinale leaves are rich in bioactive compounds with significant antioxidant potential, supporting their traditional applications and possible use in natural antioxidants development.