Fungicidal Potential of Parkia biglobosa (Jacq.) G. Don Stem Bark Extracts against Candida albicans: Phytochemical Profile and Acute Toxicity Assessment

Background: Candida albicans infections present a growing therapeutic challenge due to emerging antifungal resistance. Aims: This study evaluated the phytochemical composition, in vitro antifungal potential against Candida albicans, and the acute oral toxicity of aqueous (NindA) and ethanolic (NindE) stem bark extracts of Parkia biglobosa (Jacq.) G.Don. Methods: Parkia biglobosa stem bark was extracted by maceration using distilled water (NindA) and 70% ethanol (NindE), and extraction yields were calculated. Qualitative phytochemical screening was performed to characterise secondary metabolites. Antifungal activity against Candida albicans was evaluated by broth/agar dilution methods to determine Minimum Inhibitory Concentration (MIC), Minimum Fungicidal Concentration (MFC), MFC/MIC ratio, and 50% inhibitory concentration (IC50). Acute oral toxicity was assessed in vivo in female Wistar rats following OECD Guideline 423 using a single starting dose of 2000 mg/kg body weight (bw) administered in two sequential steps of 3 rats each. Mortality, clinical signs, and body weight changes were recorded over 14 days. Results: Phytochemical screening revealed the presence of tannins, flavonoids, saponins, and polyphenols. Both extracts exhibited fungicidal activity (MFC/MIC ratio = 1). The ethanolic extract (NindE) yielded MIC = 6.25 ± 0.57 mg/mL, MFC = 6.25 ± 0.08 mg/mL, and IC50 = 0.78 ± 0.53 mg/mL12. The aqueous extract (NindA) showed MIC = 6.25 ± 0.11 mg/mL, MFC = 6.25 ± 0.17 mg/mL, and IC50= 1.17 ± 0.23 mg/mL1. NindE showed a trend towards greater potency based on its lower IC50. In the acute toxicity test, no mortality or adverse clinical signs were observed at 2000 mg/kg, classifying the extracts in GHS Category 5 (unclassified/safe). Conclusion: Parkia biglobosa stem bark extracts demonstrated fungicidal activity against Candida albicans with no observed acute oral toxicity at the tested dose, supporting their potential development as natural antifungal agents.