Optimization of solvent polarity for maximizing maysin yield and antioxidant efficacy in Eremochloa ophiuroides extracts

Reactive oxygen species (ROS) drive oxidative damage linked to carcinogenesis, cardiovascular dysfunction, neurodegeneration, and other chronic diseases. Although synthetic antioxidants such as BHA and BHT are effective radical quenchers, safety concerns have prompted interest in natural alternatives. Eremochloa ophiuroides is rich in C-glycosyl flavones, particularly maysin (6-C-glucosyl-2"-O-α-L-rhamnosyl apigenin), known for its bioactivity. This study assessed the impact of solvent polarity on phytochemical extraction and antioxidant capacity using water, hot water (90°C), 80% ethanol, 80% methanol, and 80% acetone. The 80% ethanol extract yielded the highest total phenolics (0.46 mg GAE/g), flavonoids (0.26 mg QE/g), and maysin (21.9 mg/g). It also exhibited the strongest antioxidant activities with the lowest IC50 values for DPPH radical (53.8 μg/mL), ABTS radical (34.2 μg/mL), and xanthine/xanthine-oxidase superoxide (IC50=9.1 μg/mL). Pearson’s correlation analysis revealed a strong inverse correlation between maysin concentration and the average IC50 value obtained from DPPH and ABTS assays (r=−0.93), identifying maysin as a key contributor. Additionally, proximate analysis showed high levels of ascorbic acid (883 mg/100 g) and potassium (6.6 g/100 g), suggesting synergistic antioxidant potential. These findings designate the 80% ethanol extract of E. ophiuroides as a potent, nutrient-rich antioxidant source suitable for application in functional foods, nutraceuticals, and dermo-cosmetic products targeting ROS-mediated disorders.