Bioactive Chemical Compounds of Local Chewing Sticks against Candida isolates Causing Oropharyngeal candidiasis among HIV-positive clients

Abstract

Background: Oropharyngeal candidiasis remains the most prevalent fungal opportunistic infection among human immunodeficiency virus (HIV)-infected individuals. The increasing resistance to conventional antifungal agents has necessitated exploring alternative therapeutic options from medicinal plants. Objective: This study aimed to evaluate the antifungal activity of three locally used chewing stick extracts and characterize their bioactive compounds against Candida isolates obtained from HIV-positive individuals with oropharyngeal candidiasis. Methods: Oropharyngeal swabs were collected from 350 HIV-positive individuals and cultured on Sabouraud Dextrose Agar. Candida species were identified using the API Candida identification system. Antifungal susceptibility testing was performed using the agar well diffusion method with aqueous extracts of Anogeissus leiocarpa, Bridelia ferruginea Benth, and Grewia mollis. Bioactive compounds were characterized using Gas Chromatography-Mass Spectrometry (GC-MS) and Fourier Transform Infrared (FT-IR) spectroscopy. Results: Thirty-four (9.7%) of the 350 samples yielded positive growth of Candida species. Candida krusei was the most prevalent isolate (18; 52.94%), followed by Candida famata (5; 14.71%). Among the three chewing stick extracts evaluated, Anogeissus leiocarpa demonstrated the highest antifungal activity (31; 91.2% susceptibility), with a minimum inhibitory concentration (MIC) of 6.24 mg/mL. GC-MS analysis identified 28 compounds in A. leiocarpa, 31 in B. ferruginea, and 18 in G. mollis. Major bioactive compounds included n-Hexadecanoic acid, phytol, oleic acid, and various octadecadienoic acid derivatives. FT-IR analysis confirmed the presence of functional groups including O-H, C-O-C, N-H, COOH, C=O, and C-H, indicating the presence of phenols, alcohols, amines, carboxylic acids, and alkenes. Conclusion/ Recommendations: The investigated chewing sticks, particularly Anogeissus leiocarpa, exhibit promising antifungal activity against clinical Candida isolates. The presence of diverse bioactive compounds supports their ethnomedicinal use and suggests their potential as sources for novel antifungal drug development. Future research should focus on isolating the active principles, evaluating their safety through in vivo models, and exploring the synergistic potential of these extracts with conventional antimalarials or antiretrovirals to enhance therapeutic outcomes in HIV‑positive patients.