In Vitro Evaluation of the Antimicrobial Potential of Extracts from Cymbopogon Citratus Oil, Seed of Picralima Nitida and Roots of Anacardium Occidentale Linn. Against Urogenital Clinical Pathogens

Abstract

Recently, there is a growing awareness of the role of plant-derived natural products in modern medicine. This study brought forth the case of anti-microbial properties of different extracts of Picralima nitida seed, Anacadium occidentale Linn root, and Cymbopogon citratus leaf oil, against urogenital clinical pathogens. The clinical pathogens (Candida albicans, Escherichia coli and Staphylococcus aureus) were isolated from body fluid (High Vaginal Swab (HVS), Urine, Semen Endocervical Swab (ECS), Urethral Swab (US), and Blood) of patients attending outpatient clinic of Bishop Shanahan Hospital, Nsukka. Protocols for ethical clearance were duly observed, and first person informed consent was obtained from each patient before collection of the body fluid. The plants were properly collected and washed clean in a running tap. While P. nitida seeds and A. occidentale roots were room dried and pulverized with laboratory hammer mill to a fine texture of 60micron size, the fresh sample of C. citratus was used. Aqueous extracts of each of the plants was obtained by hot water maceration for 24hours, and strained with clean muslin clothes. Methanol or n-hexane extracts were obtained by soxhlet extraction technique following standard procedures. The extracts were concentrated using rotary evaporator under vacuum. The C. citratus oil was obtained by steam distillation method using the Clevenger apparatus. The extracts were screened for their phytochemical proximate compositions using standard procedures. Antimicrobial properties of the extracts against the clinical isolates were investigated using the agar well dilution technique. Minimum Inhibition Concentration (MIC) of each extract against the clinical isolates was determined using agar dilution technique. The activities of the extracts against the clinical isolates were compared with standard drug – Gentamycin (Genteck®). Checkerboard method was used to study the interactions of the extracts among themselves, and standard drug. Results of phytochemical screening showed that the extracts of the plant parts contained alkaloids, glycosides, resins, tannins, flavonoids, terpenoids, steroids, saponins, carbohydrates, proteins and lipids. The proximate compositions of the plants were moisture 10.51%, ash16.05%, Protein 27.52%, Fats 7.42%, Fibre 2.78%, Carbohydrate 35.72% in P. nitida, moisture 16.71%, ash 14.6%, Protein 24.2%, Fats 7.42%, Fibre 4.78%, Carbohydrate 32.29% in A. occidentale, moisture 13.51%, ash 11.2%, Protein 18.05%, Fats 10.01%, Fibre 18.45%, Carbohydrate 28.78% in C.citratus. The preliminary sensitivity test showed that both hot water and n-hexane extracts of P.nitida and A. occidentale were not as effective as methanol extracts against all the test micro-organisms. The mean MIC values of the methanol extracts of P. nitida, A. occidentale and C. citratus oil against Candida albicans, Escherichia coli and Staphylococcus aureus were 13.3µg/ml, 13.5µg/ml, 9.8 µg/ml respectively. The effects of methanol extracts of A. occidentale root, P. nitida seed and C. citratus oil were sensitive to the test organisms, but the degree of sensitivity was in this order: C. citratus oil, P. nitida, and A. occidentale root. The degree of dilution required was equal to the size of the Fractional Inhibitory Concentration (FIC) – concentration of each agent in combination as conventionally determined by checkerboard titration. Sums <1, 1, >1 are indicative of synergy, additive and antagonism, respectively. The result showed more synergism. The results justify the many claims of independent researchers on the ethno-medicinal uses of the plants in the treatment of tropical diseases. This could be attributed to the presence of natural products seen in phytochemical screening.