In Vitro Assessment of Dendrocnide sinuata (Blume) Leaf Extract: A Potent Source of Antioxidants and Antimicrobial Agents Against Urinary Tract Infections

Abstract

Dendrocnide sinuata (Blume) Chew, commonly known as the "stinging tree," is an integral part of the ethnomedicinal landscape of North-East India, traditionally used to treat jaundice, fevers, and microbial infections. Despite its widespread use by indigenous tribes, the scientific validation of its bioactive constituents and pharmacological efficacy remains limited. In this study, leaf extracts of D. sinuata were prepared using methanol and ethanol through the maceration process. The phytochemical profile was characterized using Fourier-Transform Infrared Spectroscopy (FTIR) and Gas Chromatography-Mass Spectrometry (GC-MS). Biological evaluation included the DPPH free-radical scavenging assay for antioxidant capacity and the disc diffusion method to assess antibacterial activity against five uropathogenic bacterial strains: Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Enterobacter aerogenes, and Enterococcus sp. FTIR analysis identified key functional groups, including polymeric hydroxyl (-OH), aliphatic C-H, and carbonyl (C=O) groups, while GC-MS chromatograms revealed a complex profile with approximately 27 peaks, featuring a major bioactive constituent at Rt = 34.17 min. Both extracts demonstrated dose-dependent antioxidant activity, with the ethanolic extract showing superior potency (IC50 = 85.82 µL; maximum scavenging of 69.4%). Antimicrobial assays revealed broad-spectrum efficacy, with the methanolic extract exhibiting a remarkable 28 mm zone of inhibition against E. aerogenes, nearly equivalent to the Gentamicin control 29 mm. E. coli was notably susceptible to the ethanolic extract 23 mm. The findings provide empirical evidence supporting the traditional use of D. sinuata. The significant antioxidant and anti-uropathogenic properties observed suggest that the plant is a rich reservoir of bioactive molecules, particularly long-chain fatty acids and phenolics, which hold potential for the development of novel therapeutic agents to combat oxidative stress and antibiotic-resistant urinary tract infections.