Efficacy of Citrullus colocynthis and Solanum surattense extracts against bacteria isolated from clinical environments

Knowledge and awareness about the side effects of antibiotics have increased the use of traditional medicine. The search for new drugs with antimicrobial potential has increased the importance of medicinal plants worldwide. The present study investigated the antimicrobial potential of Solanum surattense (Spiny nightshade) and Citrullus colocynthis (Bitter apple) fruit extracts against the clinical isolates (n=50). The isolated bacteria were identified as Gram positive (Staphylococcus aureus (14), Staphylococcus epidermidis (3), Bacillus subtilis (13), Micrococcus luteus (4), Streptococcus pyogenes (1), Enterococcus faecalis (1) and Gram negative (Escherichia coli (11), Klebsiella pneumoniae (3)) by Gram staining and standard biochemical tests. Selected pathogens were tested against nine selected antibiotics by Kirby-Bauer disc diffusion method. Increased antimicrobial resistance was observed against most of the antibiotics. 87.5% S. aureus and S. epidermidis were found resistant to methicillin. E. coli and K. pneumoniae showed resistivity of 71.42% against ampicillin and penicillin while all the isolates of Bacillus subtilis (100%) were susceptible against chloramphenicol. Bacterial sensitivity was also accessed using the disc diffusion method against methanolic, ethanolic, acetonic, chloroform and aqueous fruit extracts of Solanum surattense and Citrullus colocynthis. Significant antimicrobial activity was observed in the aqueous extract of the S. surattense i.e., 18% of inhibition zones were greater than 20 mm and the highest zone of inhibition obtained from aqueous fruit extract was 25 mm against S. aureus. The methanolic fruit extract of C. colocynthis showed the highest inhibition zone, 21 mm, against S. aureus. Our findings concluded that the pathogenic bacteria were mostly resistant to antibiotics. However, fruit extracts of Solanum surattense and Citrullus colocynthis exhibited notable antimicrobial activity. They may be explored for well-being and improved health standards by studying as an antimicrobial agent against various diseases like cold cough, diabetes, ulcer, respiratory and urinary diseases.