Evaluation of in vitro antioxidant and in Vivo analgesic potential of Terminalia paniculata aqueous bark extract

摘要

The Terminalia genus includes plants that are used in a variety of food, nutritional products, and traditional medicines. Aqueous bark extract of Terminalia paniculata (TPW) was screened for its antioxidant and analgesic potential. The major polyphenols were identified by high-performance liquid chromatography. In vitro antioxidant potential of TPW was investigated by 1,1-diphenyl-2-picryl hydrazyl (DPPH), 2,2′-azinobis-(3- ethylbenzothiazoline-6-sulfonic acid) (ABTS2-) radical assay, nitric oxide (NO) scavenging, superoxide scavenging (O2-), Fe2+ chelating (O-phenanthroline), and ferric reducing/antioxidant power (FRAP) assay. We evaluated the effects of TPW on cell viability, lipopolysaccharide (LPS)-stimulated reactive oxygen species (ROS), nitrite, and cytokines (interleukin [IL] 6 and tumor necrosis factor alpha [TNF-α]) in RAW 264.7 murine macrophages. Evaluation of analgesic activity of TPW was performed using acetic acid-induced writhing and hot plate test in mice. Phytochemical analysis showed the presence of four polyphenols, namely, gallic acid, ellagic acid, rutin, and quercetin. TPW showed maximum superoxide, ABTS2-, NO, DPPH inhibition, and Fe2+-chelating property at 400 μg/mL, respectively. FRAP value was 4.5±0.25 μg Fe(II)/g. TPW, per se, did not affect RAW 264.7 cell viability. In LPS-induced RAW 264.7 cells, TPW attenuated the elevation in ROS, nitrite, IL-6, and TNF-α levels. TPW (100-400 mg/kg, orally) significantly reduced the number of writhes in a dose-dependent manner compared with the control. Similarly, TPW (400 mg/kg, orally) evoked a significant increase in the maximum percentage effect in the hot plate test. The study suggests the efficacy of aqueous bark extract of T. paniculata as a potential antioxidant and analgesic agent.