Synergistic Growth Inhibition of Herbal Plant Extract Combinations against Candida albicans

Abstract

Many skin diseases are caused by microbial infections. Representative pathogenic fungus and bacterium that cause skin diseases are Candida albicans and Staphylococcus aureus, respectively. Malassezia pachydermatis is a fungus that causes animal skin diseases. In this study, we propose a method for removing pathogenic microorganisms from the skin using relatively safe edible herbal extracts. Herbal extracts were screened for skin health through the removal of pathogenic microorganisms, and combinations for effective utilization of the screened extracts were identified. In this study, among methanol extracts of 240 edible plants, C. albicans, S. aureus, and M. pachydermatis were killed by extracts of 10 plants: Acori Gramineri Rhizoma, Angelicae Tenuissimae Radix, Cinnamomi Cortex, Cinnamomi Ramulus, Impatientis Semen, Magnoliae Cortex, Moutan Cortex Radicis, Phellodendri Cortex, Scutellariae Radix, and Syzygii Flos. By evaluating the synergistic antifungal activities against C. albicans using all 45 possible combinations of these 10 extracts, five new synergistic antifungal combinations, Acori Gramineri Rhizoma with Magnoliae Cortex extracts, Acori Gramineri Rhizoma with Phellodendri Cortex extracts, Angelicae Tenuissimae Radix with Magnoliae Cortex extracts, Magnoliae Cortex with Phellodendri Cortex extracts, and Phellodendri Cortex with Syzygii Flos extracts, were identified. By utilizing the selected extracts and five combinations with synergistic antifungal effects, this work provides materials and methods to develop new and safe methods for treating candidiasis using natural products.