In vitro and in vivo antimicrobial evaluation of alkaloidal extracts of Enantia chlorantha stem bark and their formulated ointments.

The in vitro and in vivo antimicrobial evaluation of the formulated ointment of alkaloidal extract of Enantia chlorantha Oliv. (Annonaceae) was the concern of this study. The alkaloidal fraction of the stem bark extract was formulated into simple ointment using British Pharmacopoeia formula for preparation of simple ointment. Agar diffusion and agar dilution methods were used for the in vitro antimicrobial studies. Ketoconazole 4000 μg/mL and tioconazole cream 1% were used as reference standards while normal saline was used as control. The fungicidal activity kinetics of the plant extract was carried out using selected concentrations of the plant extract against the most sensitive organism (Candida albicans). For the in vivo studies, 25 albino rats weighing between 180-200 g were divided into 5 groups, anesthesized (thiopental sodium 50 mg/kg), infected with overnight culture of Candida albicans and incubated at 37 degrees C for three days to allow for growth of the microorganisms. Each of the five groups was treated on the third day of incubation with different concentrations of the formulated simple ointment (200 mg/mL, 100 mg/kg, 50 mg/mL), tioconazole cream 1% (reference standard) and normal saline control, respectively. The alkaloidal extract exhibited greater zones of inhibition with Candida glabrata and Trichophyton tonsurans while Candida albicans and Trichophyton interdigitali also showed some sensitivity. There was no surviving organism at the end of 240 min at 100 mg/mL concentration with 10(-4) dilution factor. Treatment of the infected rats with the formulated simple ointments (200, 100 and 50 mg/mL) showed that 50 mg/mL ointment had a better percentage reduction in the fungal loads at the end of the experiment when compared with the 200 mg/mL simple ointment as well as the standard tioconazole 1% cream and normal saline treated rats, respectively. The alkaloidal fraction of Enantia chlorantha stem bark as well as the formulated ointment exhibited significant in vitro and in vivo antifungal activities against different species of Candida, dermatophytes and plant fungi.