GC-MS characterization and bioactivity studies of aerial part of Hilleria latifolia (lam) extract and fractions: Antioxidant and antibacterial potentials

Abstract

This study sets out on identifying active compounds within Hilleria latifolia (Lam) extracts and fractions, with a specific emphasis on their  potential antibacterial and antioxidant activities. GC-MS analysis was employed to characterize the chemical constituents in the n-hexane  (n-Hex) and dichloromethane (DCM) fractions. The nHex and DCM fractions of the aerial part of Hilleria latifolia (Lam) revealed the  presence of 45 compounds (27 in n-Hex and 18 in DCM), many of which are known for their antioxidant, anticancer, anti-inflammatory,  and antibacterial properties. Antioxidant activity was evaluated through iron-reducing power (FRAP), nitric oxide (NO) inhibition, metal  chelating ability (MC), total antioxidant capacity (TAC) and 2,2-diphenyl-1- picrylhydrazyl (DPPH) assays. The EtOAc fraction showed the  best activities in DPPH (IC 0.70±0.026 50 mg/mL), FRAP (478.503±8.607 mg AAE/g), MCA (0.199±0.085 mg/mL) and TAC (227.37±60.949 mg AAE/g). The sensitivity testing of the crude methanolic extract and fractions were carried out using the agarwell diffusion method against  three gram-positive (Bacillus stearothermophillus, Staphylococcus aureus, and Micrococcus luteus) and five gram-negative  (Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Proteus vulgaris, and Serratia marcescens) bacterial strains. The  crude methanol extract and aqueous fraction did not show activity towards all the bacterial strains. However, the n-Hex fraction exhibited  moderate antibacterial activity particularly against K. pneumoniae (12 mm), M. luteus (9 mm), P. aeruginosa (12 mm), B.  stearothermophillus (10 mm), and S. aureus (12 mm), the DCM fraction also showed effective antibacterial activity against K. pneumoniae  (16 mm), M. luteus (12 mm), P. vulgaris (11 mm), B. stearothermophillus (12 mm), E. coli (12 mm) and S. aureus (11 mm). The ethyl acetate (EtOAc) fractions have shown considerable antibacterial activity against K. pneumoniae (12 mm), M. luteus (12 mm), P.  vulgaris (11 mm), B. stearothermophillus (12 mm) and S. aureus (8 mm). The present findings demonstrate the antioxidant and  antibacterial properties of Hilleria latofolia fractions, underscoring the need for further research to confirm their medicinal potential and  explore its pharmaceutical applications.