*1Odeyemi, O., and 2Enweani-Nwokelo, I. B.
1Faculty of Medical Laboratory Science, Achievers University, Owo, Nigeria
2Faculty of Medical Laboratory Sciences, Nnamdi Azikiwe University, Awka, Nigeria
*Correspondence to: yemiode@yahoo.com; Tel: +2347032971869
Abstract:
Background: Dermatophytosis is a highly contagious superficial mycosis of the genera Trichophyton, Epidermophyton and Microsporum that affects both man and animal. The different plant parts of Nauclea latifolia are known to have ethnomedicinal uses. The objective of this study is to access the phytochemical components of N. latifolia plant parts and to investigate the anti-fungal activities and time-kill kinetics of the plant parts against isolated dermatophyte species.
Methodology: The pulverized parts (root, stem, leaf, fruit) of authenticated N. latifolia plant were extracted using cold maceration method for 48 hours in methanol. The extracts were then concentrated almost to dryness and the phytochemical constituents assessed. The preliminary screening of the anti-dermatophytic activities of the extracts was determined by the agar disc diffusion technique on selected dermatophytes, consisting of two isolates of Microsporum ferrugineum (strains 1 and 2), two isolates of Trichophyton mentagrophytes (strains 1 and 2), one isolate of Microsporum audouinii and one isolate of Microsporum canis. The minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC) and time-kill kinetics of the extracts were determined using standard methods on the selected dermatophytes.
Results: The pulverized stem bark of the plant had higher yield of 12.73% when compared to other plant parts (leaf; 4.44%, root; 1.53%, and fruit; 4.16%). All extracts of the plant parts contain flavonoids and tannins, with the stem bark and fruit extracts containing tannins in higher concentrations. The leaf and root extracts of the plant contained saponin, but this is absent in the stem bark and fruit extracts. There were no zone diameters of inhibition produced by different concentrations of the root and leaf extracts against the selected dermatophytes while the mean zone diameters of inhibition produced by the stem bark and fruit extracts was appreciably low (range 2.0±00-10±2.00mm) at 500mg/ml of the extracts. The MICs and MFCs were the same for stem bark and fruit extracts at 62.5mg/ml for T. mentagrophyte strain 2 and M. ferrugineum strain 2, and at 250mg/ml for M. audouinii. Similarly, the MICs and MFCs were the same for the stem bark extracts at 125mg/ml for T. mentagrophyte strain 1. In the time-kill assay, reduction in the count of the viable cells occurred within 0-1 hour, and at 8 hours, there were no viable cells.
Conclusion: Crude methanol extracts of N. latifolia stem bark and fruit exhibited fungicidal activity against the selected dermatophytes, albeit at high concentration above what is considered to indicate potential efficacy of an extract for further therapeutic exploration. Nevertheless, the time-kill assay result holds promise that the stem bark and fruit extracts of the plant potentially possess anti-dermatophytic activity that could justify the plant use for treating dermatophyte infections.
Keywords: Dermatophyte, phytochemicals, methanol extraction, time-kill kinetics, Nauclea latifolia
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