Antifungal activity of extracts from selected Kenyan medicinal plants
Abstract
The use of medicinal herbs in the treatment of diseases is an age-old practice.
In Kenya' several plant species are used by many ethnic groups for treatment
of various diseases raging from minor infections to asthma, dysentery, skin
diseases and a horde of others.
To establish the claimed therapeutic efficacy of some commonly used
medicinal plants, in vitro antifungal activity tests of extracts from 28 Kenyan
medicinal plant species was carried out. The activity of the extracts was
studied on three human pathogens, Trichophyton mentagrophytes Robin,
Microsporum gypseum Bodin and Candida albicans (Robin) Berkh. and one
plant pathogenic fungus Cladosporium cucumerinum Ellis and Arth .. The disc
assay method was used for the evaluation of fungitoxicity. Bioactivity guided
fractionation was done for extracts that showed measurable activity.
Extracts from 17 plant sQecles were variably active against Trichophyton
mentagrophytes, Microsporum gypseum, Candida albicans and Cladosporium
cucumerinum. The plant species included, Acacia nilotica (L.) Del, Acacia
senegal (L.) Willd, Adenia volkensii Harms, Ajuga remota Benth., Aporrhiza
-paniculata Radlk., Aspilia pluriseta Schwieinf. Ex. Engl., Azadirachta indica
A. Juss., Senna didymobotrya (Fresen.) Irwin and Batneby, Commiphora
africana (A. Rich.) Engl., Hymenodictyon parvifolium Oliv., Plectranthus
barbatus Andr., Plectranthus cylindraceus Benth., Premna resinosa (Hochst
Schauer, Schizozygia coffaeoides Baill, Solanum arundo Mattei, Solanum
nigrum L. and Tagetes minuta L. Bioactivity guided fractionation led to the
isolation of a potent antifungal compound from Schizozygia coffaeoides Baill.
From spectroscopic and chemical analysis, the compound was determined as
an indole alkaloid with a molecular formula C21H22N204 .The compound was
fungistatic in action and affected the filamentous and yeast fungi by causing
swelling and gloss morphological distortions.
From the results of this study, it is evident that some Kenyan medicinal plants
have properties which could be exploited for the management of pathogenic
fungi in humans and plants.