DR. ANNE O. ITEMIRE

The emergence of antifungal resistance necessitates the exploration of plant-based alternatives. This study investigated the antifungal activity of Syzygium aromaticum (clove) extracts prepared by Soxhlet and maceration methods. Clove buds were authenticated, extracted using ethanol– water (1:1), and tested against 12 fungal isolates, including Candida albicans, Aspergillus niger, Penicillium spp., and Fusarium spp. Antifungal susceptibility was assessed using agar well diffusion, while minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined by agar dilution. Ketoconazole served as the standard reference. Results showed concentration-dependent inhibition, with activity evident from 50 mg/ml. Candida albicans was the most sensitive organism, with inhibition zones up to 17.66 mm at 400 mg/ml, while Penicillium showed the least susceptibility. Maceration extracts consistently demonstrated higher efficacy than Soxhlet, yielding larger inhibition zones and lower MIC values (41.66 ± 12.12 µg/ml vs. 200.00 ± 145.5 µg/ml for Candida albicans). MFC assays confirmed fungicidal activity of maceration extracts at 50 µg/ml for Candida albicans, compared to higher concentrations required for other fungi. These findings indicate that Syzygium aromaticum possesses notable antifungal properties, particularly against Candida albicans, with maceration proving the more effective extraction method. The results provide scientific support for clove’s traditional use and suggest its potential as a natural antifungal agent.

Antimicrobial resistance (AMR) has become a major global health concern and a menace
to the efficacy of existing antimicrobials, necessitating the exploration of alternative
agents. Medicinal plants have the potential to provide novel therapeutic options against
microbial infections. Cymbopogon citratus (lemongrass) and Picralima nitida (Akuamma)
are widely recognized for their antimicrobial effects, among other pharmacological
activities. This study aimed at evaluating the antimicrobial activity of a bi-herbal
formulation of Cymbopogon citratus (lemongrass) and Picralima nitida (Akuamma)
against selected pathogenic microorganisms. Aqueous and ethanol leave extracts of
Cymbopogon citratus and Picralima nitida were used. An inoculum size of 10
5 CFU/ml
was applied. Antimicrobial susceptibility test was carried out using agar well diffusion
method with some modifications. The results showed that the MICs of the aqueous and
the ethanol leave extracts on Staphylococcus aureus were 200 mg/ml and 20.83 mg/ml
with zones of inhibition of diameters 11.50 mm and 11.33 mm, respectively. Also, the
MICs of the aqueous and the ethanol leave extracts on Bacillus subtilis were 150 mg/ml
and 6.37 mg/ml with zones of inhibition of diameters 15.00 mm and 15.50 mm, respectively. The MIC of the aqueous extract on C. albicans was 75 mg/ml with a zone of
inhibition diameter of 12.00 mm; however, the ethanolic extract did not produce any zone
of inhibition. No zones of inhibition were observed in K. pneumonia and Aspergillus
niger. In conclusion, both the aqueous and ethanol bi-herbal formulations of
Cymbopogon citratus and Picralima nitida leaves possess antimicrobial property against
Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, although these
organisms were more susceptible to the ethanol extract. The formulation is not effective
against Gram-negative organisms such as Klebsiella pneumonia and Escherichia coli, as
well as fungi such as Aspergillus niger but had slight activity against Candida albicans. Further research is recommended to elucidate the efficacy, safety, and toxicity of this
formulation.