Potent and Synergistic Extract Combinations from Terminalia Catappa, Terminalia Mantaly and Monodora tenuifolia Against Pathogenic Yeasts

Abstract

Mycoses caused by <i>Candida</i> and <i>Cryptococcus</i> species, associated with the advent of antifungal drug resistance have emerged as major health problems. Improved control measures and innovative therapies are needed. This paper describes results from the screening of bio-guided fractionated extracts alone and combinations of <i>Terminalia catappa, Terminalia mantaly</i> and <i>Monodora tenuifolia</i> harvested in Cameroon. Crude ethanolic, hydro-ethanolic and aqueous extracts and bio-guided fractions were screened for antifungal activity against isolates of <i>C. albicans</i>, <i>C. glabrata</i>, <i>C. parapsilosis</i> and <i>Cr. neoformans</i> and the reference strain <i>C. albicans</i> NR-29450. Minimal inhibitory concentrations (MIC) were determined using a broth micro dilution method according to the Clinical &amp; Laboratory Standards Institute (CLSI). Time kill kinetics of extracts alone and in combination were also evaluated. Extracts from <i>T. mantaly</i> stem bark were the most active with the best MIC values ranging from 0.04 mg/mL to 0.16 mg/mL. Synergistic interactions were observed with combinations of sub-fractions from <i>M. tenuifolia</i>, <i>T. mantaly</i> and <i>T. catappa.</i> Combination of sub-fractions from <i>M. tenuifolia</i> and <i>T. mantaly</i> (C36/C12) showed synergistic interaction and fungicidal effect against four out of five tested yeasts. These results support further investigation of medicinal plant extracts alone and in combination as starting points for the development of alternative antifungal therapy.