Antifungal and Cytotoxicity Activity of Plants Used as Herbal Teas in Tanzania

Aim: The current study was designed to determine antifungal and cytotoxicity activity of Rhus vulgaris, Sphaeranthus bullatus, Osyris lanceolata, Ocimum gratissimum, Cymbopogon citratus, Acacia nilotica and Tylosema fassoglensis used as herbal teas in Tanzania.

Study Design: In vitro antifungal assay and brine shrimp lethality test for cytotoxicity study.

Methodology: Broth dilution using 96-well micro dilution method was used in antifungal assay. Extracts were loaded in the wells of the first row, followed by serial dilution and 50 μl of the fungal suspensions (0.5 MacFarland standard turbidity) were added in each well. The first concentration which showed no fungal growth was considered as Minimum Inhibition Concentration (MIC). On the other hands Brine shrimp lethality test were employed to determine cytotoxicty activity. Ten brine shrimp were added to vials contains different concentration (240, 120, 80, 40, 24 and 8 μg/mL) of the extracts dissolved in DMSO. Each concentration was tested in duplicate to establish the number of surviving brine shrimp.

Results: Antifungal activity was demonstrated by all extract with the minimum inhibition concentration (MIC) value range from 1.56 mg/mL – 25 mg/mL against Candida albicans and Cryptococcus neoformans. The later fungus was susceptible to extracts tested compared to the former. Of the all extract tested 18% were non toxic against Artemia salina with lethal concentration (LC50) value above 100 μg/mL. The highest cytotoxicity was exhibited by Acacia nilotica ethyl acetate root extract with LC50 0.57 μg/mL.

Conclusion: Results of this study showed that extracts tested demonstrate moderate to weak antifungal activity and strong to weak cytotoxicity effects. Further study is required on these plant extracts to characterize bioactive compounds responsible for observed activities. Moreover, further toxicological studies are required in order to establish these plants as herbal teas which can be used for both refreshment and management of diseases.