PHYTOCHEMICAL ANALYSIS AND ANTIMICROBIAL ACTIVITY OF WATERMELON SEED EXTRACT ON STREPTOCOCCUS SPECIES

Abstract

This study investigated the phytochemical composition and antimicrobial efficacy of watermelon seed extract against Streptococcus species, a pathogenic bacterial genus associated with various infections. The research aimed to identify and analyse bioactive compounds within watermelon seeds that could provide antimicrobial properties. Watermelon seeds were collected and processed through solvent-based extraction methods, and phytochemical screening revealed the presence of flavonoids, alkaloids, tannins, and saponins compounds known to enhance antimicrobial efficacy. The antimicrobial potential was assessed using the agar well diffusion method, where the seed extract exhibited significant zones of inhibition against various Streptococcus strains, including Streptococcus pyogenes, Streptococcus oralis, Streptococcus salivarius and Streptococcus faecalis. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values were determined, with the MIC values ranging between 12.5 mg/ml and 50 mg/ml, and MBC values indicating bactericidal effects against the tested strains at varying concentrations. Notably, Streptococcus pyogenes exhibited the highest susceptibility, requiring a lower MIC and MBC for effective inhibition and control. The phytochemical analysis of watermelon seed extract revealed significant concentrations of carbohydrates (74.96–76.51 mg/100g), alkaloids (62.44–65.34 mg/100g), and reducing sugars (39.42–41.28 mg/100g), along with moderate levels of flavonoids, phenolic compounds, and other bioactive constituents. These results demonstrate the potential of watermelon seed extract as a natural antimicrobial agent, particularly against Streptococcus species, and suggest its applicability in addressing infections caused by antibiotic-resistant bacteria. The findings highlight watermelon seed extract as a promising candidate for developing alternative treatments for bacterial infections, given its phytochemical richness and effective inhibition of pathogenic bacteria.