Colorimetric broth microdilution method for the antifungal screening of plant extracts against yeasts

Manjuan Liu, Veronique Seidel, David R. Katerere, Alexander I. Gray

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

Screening plant extracts for antifungal activity is increasing due to demand for new antifungal agents, but the testing methods present many challenges. Standard broth microdilution methods for antifungal susceptibility testing of available antifungal agents are available now, but these methods are optimised for single compounds instead of crude plant extracts. In this study we evaluated the standard NCCLS method as well as a modification which uses spectrophotometric determination of the end-points with a plate reader. We also evaluated another standard method, the EUCAST method, which is a similar microdilution assay to the NCCLS method, but uses a larger inoculum size and a higher glucose concentration in the medium as well as spectrophotometric end-point determination. The results showed that all three methods had some drawbacks for testing plant extracts and thus we modified the NCCLS broth microdilution method by including a colorimetric indicator—resazurin for end-point determination. This modified method showed good reproducibility and clear-cut end-point, plus the end-point determination needed no instruments. It enabled us to evaluate the activity of a selection of extracts from six Combretaceous plants against three Candida spp. and thus provided pharmacological evidence for some traditional uses of these plants while assisting the identification of the active ingredients.
Original languageEnglish
Pages (from-to)325-329
Number of pages5
JournalMethods
Volume42
Issue number4
DOIs
Publication statusPublished - Aug 2007

Keywords

  • combretaceae
  • candida
  • broth microdilution
  • NCCLS
  • EUCAST
  • resazurin
  • natural products
  • antifungal tests

Fingerprint Dive into the research topics of 'Colorimetric broth microdilution method for the antifungal screening of plant extracts against yeasts'. Together they form a unique fingerprint.

Cite this