Quantitative Phytochemical Constituents and Antioxidant Activities of the Mistletoe, Phragmanthera capitata (Sprengel) Balle Extracted with Different Solvents

Objective: The investigation aimed to evaluate the in vitro quantitative phytochemical compositions and antioxidant capacity of the dried leaves of Phragmanthera capitata extracted with different solvents. Methodology: Different phytochemical assays were used to evaluate the phenols, flavonoids, and proanthocyanidin contents of the acetone, methanol, ethanol, and aqueous extracts of the sample. Antioxidant activity was measured using 2,2diphenyl‑1‑picrylhydrazyl (DPPH), 2,2′‑azino‑bis (3‑ethylbenzthiazoline‑6‑sulfonic acid) (ABTS), Ferric reducing antioxidant power (FRAP), nitric oxide, and total antioxidant capacity (TAC) assays. Results: Methanol had the highest extraction yield (21.50%) followed by aqueous (10.87%). Acetone and ethanol yielded 6.87% and 4.3%, respectively. However, acetone and ethanol extracts had more phenolic content (218.6 ± 3.38 and 214.8 ± 3.56 mg gallic acid equivalent (GAE)/g, respectively) that were significantly higher (P < 0.05) than the methanol and aqueous extracts (203.8 ± 1.95 and 175.5 ± 0.32 mg GAE/mg, respectively). Acetone extract also had more flavonoid and proanthocyanidin contents (679.8 ± 6.26 mg quercetin equivalent/g and 645.7 ± 6.35 mg catechin equivalent/g, respectively) that were significantly higher than the other solvent extracts (P < 0.05). All the solvent fractions showed great antioxidant activities with the acetone fraction having the highest capacity based on ABTS, DPPH, and TAC assays (half maximal inhibitory concentration [IC50] = <5 µg/ mL, 24.5 µg/mL, and 85 µg/mL respectively). The methanol extract however had FRAP and nitric oxide antioxidant activities (IC50 = 302 µg/ mL and <25 µg/mL respectively). Conclusion: The findings of this study provide evidence that P. capitata has potential as a natural source of antioxidant with acetone showing to be the best extractant of the polyphenolics with corresponding higher antioxidant activities.