Antidermatophytic activity and adverse side effects of the methanolic extract from leaves of Ageratum conyzoides (Asteraceae)

Abstract

Background: The incidence of dermatophytosis has increased in recent years in spite of the availability of antifungal drugs. Faced with all the above, medicinal plants could be an alternative. So, this work aimed at evaluating antidermatophytic activities of some medicinal plants used in Cameroon against dermatophytoses.

Methods: An ethnopharmacological survey was carried out by interview of traditional healers in six villages of Bafou locality. Nine plants were selected and methanol extracts were prepared therefrom. The in vitro antidermatophytic activities of these extracts were tested using microdilution method. The degree of dermal irritation of the extract from leaves of Ageratum conyzoides was determined in Cavia porcellus using the occluded dermal irritation test method. This extract was subjected to an acute dermal toxicity test using C. porcellus as animal model. For that, animals were randomly divided into four groups: Groups 1, 2 and 3 respectively received single doses of extract at 8000 mg/kg, 4250 mg/kg and 500 mg/kg body weight while control group received distilled water.

Results: Among the tested extract, that of leaves of A. conyzoides showed the best antidermatophytic activity (32≤MIC≤512 μg/mL). Dermal administration of the single dose of this extract led to skin irritation, weakness and less motor activities at the dose of 8000 mg/kg. The lethal dose fifty (LD₅₀) was defined as greater than 8000 mg/kg. In general, biochemical as well as hematological parameters of animals were normal.

Conclusions : These results show that A. conyzoides is the most effective against dermatophytes without adverse side effects at reasonable doses.