The antimicrobial effectiveness of Tulbaghia violacea and Allium sativum on the in vitro growth of Candida albicans

Abstract

Aim This study sought to compare the antifungal potential of Tulbaghia violacea to that of Allium sativum. Mother tinctures and a respective selection of homoeopathic potencies were evaluated in terms of their inhibitory effect on the growth of Candida albicans in vitro.

Methodology This experimental study employed microbiological assays to evaluate the antifungal potential of Tulbaghia violacea (wild garlic) while comparing this activity to Allium sativum (garlic) against Candida albicans in vitro. Allium sativum bulbs and fresh Tulbaghia violacea bulbs and leaves were processed into 1:2 ethanolic extracts. These were diluted into 1:10 mother tinctures in 8% ethanol and succussed to prepare respective 3CH, 5CH, 8CH, 13CH and 21CH homoeopathic potencies (CHcentesimal Hahnemannian – diluting substance by a factor of 100 followed by rigorous shaking before the next dilution). The inhibitory effect of the respective preparations was investigated using the microtitre plate assay. The absorbance of Candida albicans, in Sabouraud dextrose broth, was measured at 630 nm with a Multiskan Go microplate spectrophotometer in the presence and absence of selected test substances. The absorbance readings of the test groups were compared to the negative control (Candida albicans left untreated). Additionally, disc- and well diffusion assays were used to further explore the antifungal effectiveness by measuring the zones of inhibition in Sabouraud dextrose agar plates.

Quantitative data analysis was conducted using the Statistical Package for the Social Sciences (SPSS) version 25. Descriptive statistics were used to analyse the sets of data produced from the microtitre assay. The differences between the Pre- and postincubation absorbance was analysed. Results The microtitre assay produced data, which was used for the comparative analysis of the 1:10 mother tincture, 3CH, 5CH, 8CH, 13CH and 21CH test groups indicated that the 1:10 mother tinctures were the most statistically significant test group as p = 0.006. Additionally, the analysis confirmed that the inhibitory properties of Allium sativum were better than that of Tulbaghia violacea. The pairwise comparative analysis found that all tested groups were statistically significant when compared to the negative control (Candida albicans left untreated). Both the well and disc diffusion assay did not produce measurable zones of inhibition and therefore no comparative data were obtained from this investigation.

Conclusion The study found that Tulbaghia violacea mother tinctures and homoeopathic potencies were effective in inhibiting the growth of Candida albicans. It can be concluded that Tulbaghia violacea does indeed contain antifungal properties, which can be further investigated by means of in vivo testing. According to the comparative analysis Allium sativum demonstrates better antifungal effectiveness than Tulbaghia violacea.