ANTIMICROBIAL ACTIVITY OF METHANOLIC EXTRACT OF THE LEAVES OF RITCHIEA LONGIPEDICELLATA FAM. CAPPARIDACEAE

Anowi CF, Utoh-Nedosa UA, Onyegbule AF and Oche G

Ritchiea longipedicellata Gilg had been reported in traditional medicine, to exhibit antimicrobial properties. Therefore, this study is aimed at determining the antibacterial and antifungal activities of Ritchiea longipedicellata Gilg leaves against pathogenic microorganisms by determining the minimal inhibitory concentration and to serve as criteria to recommend the ethno pharmacological uses of the plant. Plant leaves were dried, powdered and extracted by cold maceration with methanol for 24hours. Phytochemical screening was done for alkaloids, saponin, essential oil, phenolic group, steroidal nucleus, simple sugar, starch, cyanogenic glycoside, proteins and flavonoids using standard procedures. Antimicrobial and minimal inhibitory concentration screenings were done using agar diffusion technique. Antibacterial activity test was conducted by screening against seven pathogens comprising both Gram positive and Gram negative bacteria obtained from Pharmaceutical Microbiology laboratory stock. The extracts were screened against 24hour broth culture of bacteria seeded in the nutrient agar at concentrations 200, 100, 50, 25, 12.5 and 6.25 mg/ml in DMSO and incubated at 370C, for 24 hours and measuring the inhibition zone diameter - IZD. The same was done for antifungal screening, however, fungi were seeded into a sabouraud dextrose agar and incubated for 72 hours at 250C (.Aspergillus niger and Candida albican were used). The positive controls were ampicillin 20μg/ml and clotrimazole cream 1mg/ml for bacteria and fungi respectively. DMSO was used as negative control. The results of phytochemical screening showed moderate availability of alkaloid, simple sugar and abundance of flavonoids, steroidal nucleus, essential oil, phenolic group, cyanogenic glycoside; absence of starch and protein and doubtful quantity of saponin. Methanolic extract inhibited with minimal inhibitory concentration of 200, 6.25, 200, 12.5, and 12.5 mg/ml against S. aureus, P. aeruginosa, S. typhi, E. coli, B. subtilis, and Sarcinae lutea respectively. The extract demonstrated activities against certain bacteria confirming the use of the plant in ethno pharmacology and since the root extract are more often used, it is yet to be confirmed if it has more activity than the leaves against the test organisms. Taking the least IZD of the standard (Ampicillin) as the breaking point, most of the extracts passed the breaking point.