In vitro Anti-candidal Activity of Extracts of Some Selected Medicinal Plants on Clinical Isolate of Candida albicans and Its Standard ATCC 10231 Strain

Aim: Extracts of four different medicinal plant parts such as stem bark of Murayya koenigii (Curry leaf plant), fruit peel of Punica granatum (Pomegranate), cloves of Allium sativum (Garlic) and rhizome of Zingiber officinale (Ginger) were used to test their anti-candidal activity on clinical isolate of Candida albicans and its ATCC 10231 strain.

Methodology: Culture test, germ tube test and chlamydospore formation test were used for the confirmation of C. albicans isolates. Disc diffusion method was evaluated for anti-candidal activity. Secreted aspartyl proteinase (SAP) enzyme was assayed spectrophotometrically using bovine serum albumin as substrate.

Results: Out of ten isolates of Candida albicans made in the laboratory, isolate 5 showed good growth as compared to its standard culture ATCC 10231. Optimum temperature and pH was found to be 35 - 40ºC and pH 3.5 – 4, respectively. The garlic extract exhibited better anti-candidal activity on clinical isolate 5 and ATCC 10231 than the other plant extracts, as the zone of inhibition was found to be 28 mm for isolate 5 and 30 mm for ATCC 10231. Allicin, a highly unstable molecule was found to be a major ingredient of Allium sativum, and its concentration was found to be 214 µg/mL.

Conclusion: Allicin has not only exhibited good anti-candidal activity but also destroyed the Secreted Aspartyl Proteinase (SAP), a key enzyme responsible for the candidiosis in humans.