Nutritional composition, phytochemical profile, HPLC analysis, and antioxidant activity of leaf and flower extracts of Rumex nervosus from Yemen

Rumex nervosus is a widely used medicinal plant in Yemen, traditionally valued for its therapeutic properties. This study aims to address this gap by evaluating and comparing the phytochemical composition and antioxidant activities of leaf and flower extracts of R. nervosus. Ethanol and water extracts of the leaf and flower were screened for key phytochemicals, including tannins, saponins, flavonoids, terpenes/steroids, and alkaloids. The total phenols content (TPC), Total flavonoids (TFC), and total tannins (TTC) were quantified, and the antioxidant activity was assessed using 2,2-diphenyl-1-picrylhydrazyl, hydroxyl radical scavenging, 2,2′-azinobis(3-ethylbenzthiazolin-6-sulfonic acid radical scavenging, ferric reducing power, potassium ferricyanide reducing power, and total antioxidant capacity. The results revealed that Leaves showed higher TPC/TFC, while flowers had superior TTC and nutritional content P ≤ 0.05. The total phenolic, flavonoid, and tannin content in R. nervosus ranged from 121.16 ± 27.80 to 299.42 ± 6.45 mg GAE/g, 169.72 ± 13.03 to 241.59 ± 1.87 mg QE/g DM, and 254.33 ± 13.59 to 261.72 ± 2.51 mg CE/g, respectively. It showed significantly higher levels of TPC, TFC in the ethanolic extracts than in the water extracts (P ≤ 0.05). Both leaf and flower extracts exhibited strong antioxidant activity across all methods, comparable to ascorbic acid. The antioxidant activities were found to correlate with the phytochemical content, suggesting that both leaf and flower extracts of R. nervosus could serve as promising sources of nutraceuticals, natural antioxidants, and therapeutic alternatives.