Characterization and Evaluation of the Synergistic Potency of Securidaca Longepedunculata Plant Extracts with Standard drug Against Some Pathogenic Organisms as Alternative Source of Chemotherapy

Abstract

The emergence of antimicrobial resistance among pathogenic bacteria has intensified 
the search for plant-derived bioactive compounds as alternative or adjunct therapeutic 
agents. This study investigated the antimicrobial activity of Securidaca 
longepedunculata root extracts and evaluated their synergistic potential with a 
standard antibiotic against Gram-positive bacterial pathogens. Phytochemical screening 
revealed the presence of alkaloids, flavonoids, tannins, saponins, glycosides, terpenoids, 
steroids, and carbohydrates, indicating a rich reservoir of bioactive constituents. The 
crude root extract exhibited a minimum inhibitory concentration (MIC) of 50 mg/mL 
against Bacillus pyrogens, Staphylococcus aureus, and Streptococcus aureginosis. 
Fractionation by column chromatography yielded fraction X1 (F1), which demonstrated 
enhanced antibacterial activity with MIC values ranging from 12.5 to 25 mg/mL. 
Synergistic evaluation using the checkerboard assay revealed significant interactions 
between fraction X1 and the standard antibiotic against Bacillus pyrogens and 
Staphylococcus aureus, with a fractional inhibitory concentration index (FICI) of 0.50, 
corresponding to a four-fold reduction in the effective antibiotic dose. Fourier 
Transform Infrared (FTIR) spectroscopy identified characteristic O–H (3339 cm⁻¹), 
C=O (1636 cm⁻¹), and C–O (1012 cm⁻¹) functional groups, confirming the presence of 
oxygenated phytochemicals. Gas Chromatography–Mass Spectrometry (GC–MS) 
analysis of fraction X1 identified nine compounds, predominantly ethane, 1-ethoxy-1
methoxy (100%), pholedrine (15.9%), and phenol (6.93%). The combination sample 
contained twenty-three compounds, with polygalitol (28.77%), benzene 
methanesulfonamide (12.08%), and dimethyl sulfoxide (8.33%) as the major 
constituents, suggesting complex molecular interactions responsible for the observed 
synergistic antibacterial effects. These findings demonstrate that Securidaca 
longepedunculata root extracts possess promising antibacterial properties and may 
serve as effective adjuvant agents for enhancing aminoglycoside antibiotic efficacy 
against Gram-positive bacterial infections.