Withania somnifera (L.) Dunal whole-plant extracts exhibited anti-sporotrichotic effects by destabilizing peripheral integrity of Sporothrix globosa yeast cells

PLoS Negl Trop Dis. 2022 Jun 17;16(6):e0010484. doi: 10.1371/journal.pntd.0010484. eCollection 2022 Jun.

Abstract

Chronic topical cases of Sporotrichosis, a chronic fungal infection caused by the ubiquitously present cryptic members of the Sporothrix species complex, are treated with oral administrations of itraconazole. However, severe pulmonary or disseminated cases require repeated intra-venous doses of amphotericin B or even surgical debridement of the infected tissue. The unavoidable adverse side-effects of the current treatments, besides the growing drug resistance among Sporothrix genus, demands exploration of alternative therapeutic options. Medicinal herbs, due to their multi-targeting capacity, are gaining popularity amidst the rising antimicrobial recalcitrance. Withania somnifera is a well-known medicinal herb with reported antifungal activities against several pathogenic fungal genera. In this study, the antifungal effect of the whole plant extract of W. somnifera (WSWE) has been explored for the first time, against an itraconazole resistant strain of S. globosa. WSWE treatment inhibited S. globosa yeast form growth in a dose-dependent manner, with IC50 of 1.40 mg/ml. Minimum fungicidal concentration (MFC) was found to be 50 mg/ml. Sorbitol protection and ergosterol binding assays, revealed that anti-sporotrichotic effects of WSWE correlated well with the destabilization of the fungal cell wall and cell membrane. This observation was validated through dose-dependent decrease in overall ergosterol contents in WSWE-treated S. globosa cells. Compositional analysis of WSWE through high performance liquid chromatography (HPLC) exhibited the presence of several anti-microbial phytochemicals like withanone, withaferin A, withanolides A and B, and withanoside IV and V. Withanone and withaferin A, purified from WSWE, were 10-20 folds more potent against S. globosa than WSWE, thus, suggesting to be the major phytocompounds responsible for the observed anti-sporotrichotic activity. In conclusion, this study has demonstrated the anti-sporotrichotic property of the whole plant extract of W. somnifera against S. globosa that could be further explored for the development of a natural antifungal agent against chronic Sporotrichosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antifungal Agents / pharmacology
  • Antifungal Agents / therapeutic use
  • Itraconazole / pharmacology
  • Itraconazole / therapeutic use
  • Plant Extracts / pharmacology
  • Plant Extracts / therapeutic use
  • Plants, Medicinal*
  • Saccharomyces cerevisiae
  • Sporothrix*
  • Sporotrichosis* / microbiology
  • Withania* / chemistry

Substances

  • Antifungal Agents
  • Plant Extracts
  • Itraconazole

Supplementary concepts

  • Sporothrix globosa

Grants and funding

This research received no external funding. The work was carried out with internal funds received from Patanjali Research Foundation Trust, Haridwar, India. The external funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.