Phytocompounds of Bistorta macrophylla (D. Don) Sojak. as bioavailability enhancers of fluconazole and amphotericin B to better manage Candida species infections

Abstract Bistorta macrophylla (D. Don) Sojak. is a medicinal plant of high altitude and so far, not been scientifically explored? Since prehistoric times, B. macrophylla has been used to cure stomach pain, pyretic fever, flu, lungs infections, diarrhea, vomiting. The present research was aimed to examine the phytochemicals, antifungal, and synergistic potential of methanolic extracts of B. macrophylla. Methanolic extract of B. macrophylla was found to have high phenolic (191.18 ± 29.18 mg g−1 GAE) and flavonoid (26.71 ± 3.21 mg g−1 RE) content. Methanolic extract also demonstrate strong antifungal action with diameter of zone of inhibition of 17.5±0.5 mm (fungicidal) against both the strains of C. albicans (MTCC277 and ATCC90028). The minimal inhibitory concentration (MIC) of methanolic extract was found to be 62.5 µg ml−1 against C. albicans (MTCC277 and ATCC90028). In addition, the combination of methanolic extract of B. macrophylla with antifungal antibiotics (fluconazole and amphotericin B) showed synergistic interaction with MIC reduction from 4-128 folds against both candida strains. GC-MS analysis of methanolic extract revealed the presence of 15 major phytocompounds with area more than 1%. Molecular docking showed that sucrose and 9,9-Dimethoxybicyclo [ 3.3.1] nona-2,4-dione has highest binding energy of -6.3 and -5.1 KJ/mol against Cytochrome P450 14 alpha-sterol Demethylase (PDB ID: 1EA1) protein respectively. Combination of methanolic extract of B. macrophylla with antifungal antibiotics (fluconazole, amphotericin B) can be used to treat drug-resistant candida.