Simultaneous quantification of hydroxycinnamate derivatives and antioxidant activity of Ziziphus oxyphylla Edgew. leaf methanolic extract

The present study quantified hydroxycinnamate (HCIN) derivatives from the methanolic extract of Ziziphus oxyphylla Edgew. (Z. oxyphylla) leaves and evaluated the antioxidant activity. An accurate and reproducible high-performance liquid chromatography (HPLC) method for the simultaneous determination of chlorogenic acid, caffeic acid, and ferulic acid was developed, with a retention time of 4.36, 7.01, and 9.38 min, respectively. The extract exhibited a notable in vitro antioxidant activity, with IC₅₀ values of 220.91 ± 0.14, 254.28 ± 0.24, 241.96 ± 0.03, 190.17 ± 1.56, and 211.10 ± 0.10 µg/mL in DPPH radical, reducing power, H₂O₂ scavenging, phosphomolybdenum, and thiobarbituric acid (TBA) assays, respectively. In vivo, extract dose (500 mg/kg) significantly enhanced catalase (CAT: 0.18 ± 0.03 U/mg protein) and superoxide dismutase (SOD: 4.1 ± 0.3 U/mg protein) activities, while reducing thiobarbituric acid reactive species (TBARS: 0.39 ± 0.02 nmol/mg protein) compared to silymarin (0.33 ± 0.04 nmol/mg protein) at 200 mg/kg. Therefore, the Z. oxyphylla leaf extract, enriched with HCIN, demonstrated strong antioxidant potential, thereby validating its traditional ethnopharmacological applications.