Integrated Phytochemical and Pharmacological Assessment of Uraria rufescens Leaves: Insights Into Its Antioxidant, Thrombolytic and CNS Activities

Abstract

Uraria rufescens is traditionally used in Bangladesh for fever and inflammation, yet its phyto-pharmacological profile was not explored adequately. This investigation exerted the phytochemical composition and pharmacological activities of its leaves methanolic extractives (URME), focusing on in vitro antioxidant and thrombolytic, along with in vivo anxiolytic, antidepressant and analgesic effects. Phytochemical screening was conducted via various chemical tests, whereas secondary molecules were isolated using chromatographic techniques and identified by ¹H NMR spectroscopy. Antioxidant activity was evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging, total phenolic content (TPC) and total flavonoid content (TFC). Thrombolytic activity was determined by clot lysis. In vivo studies assessed antidepressant effects through forced swim test (FST) and tail suspension test (TST), anxiolytic activity by the elevated plus maze (EPM) and hole-board test (HBT), and analgesic effects by acetic acid-induced writhing and formalin-induced paw licking models. Screening confirmed the presence of alkaloids, flavonoids, glycosides, phenols, steroids and terpenoids. Seven compounds were isolated and identified for the first time from U. rufescens leaves: trans-sinapic acid 1, fisetin 2, oleanolic acid 3, aesculin 4, taraxerone 5, sitogluside 6 and syringaresinol 7. The ethyl acetate fraction showed strong antioxidant activity (IC₅₀ = 32.78 µg/mL), whereas the chloroform fraction had the highest TPC (742.24 mg GAE/g) and TFC (703.15 mg QE/g). The aqueous fraction demonstrated notable thrombolytic activity (52.03%). URME significantly reduced immobility in FST and TST, indicating strong antidepressant effects. In EPM and HBT, URME moderately enhanced open-arm time (41.8 s) and head dips (36.8 s). URME also produced dose-dependent analgesic activity in both central and peripheral models. The plant contains various phenolic compounds and exhibits strong antioxidant and thrombolytic activities, as well as dose-dependent antidepressant and analgesic effects with moderate anxiolytic potential. Further studies are needed to isolate bioactive molecules and clarify mechanisms.

Keywords: Chromatographic separation; In vitro; In vivo; Phytochemical screening; Uraria rufescens.

FIGURE 1

IC₅₀ values of DPPH free radical scavenging property of URME. (DPPH, 2,2‐diphenyl‐1‐picrylhydrazyl)

FIGURE 2

TFC of the extracts and various fractions of the plant materials. (TFC, total flavonoid content)

FIGURE 3

Estimation of TPC among the various extractives of URME. (TPC, total phenolic content)

FIGURE 4

Graphical representation of % of thrombolysis of the extractives.

FIGURE 5

Effects of URME and diazepam on immobility time in the tail suspension test. ****p < 0.0001 (extremely significant), ***p < 0.001 (very strong significant), **p < 0.01 (strong significant), *p < 0.05 (significant).

FIGURE 6

Forced swimming test (FST) showed the antidepressant action (immobility time) of URME and diazepam. ****p < 0.0001 (extremely significant), ***p < 0.001 (very strong significant), **p < 0.01 (strong significant), *p < 0.05 (significant).