Investigation the efficiency of various methods of volatile oil extraction from Trichodesma africanum and their impact on the antioxidant and antimicrobial activities

BACKGROUND Currently, there is an increasing interest in developing more efficient techniques for the extraction of phytochemicals. Microwaves and ultrasonic extraction methods are promising techniques that can be used for this purpose. OBJECTIVES The purpose of this study was to investigate the impact of different extraction methods on yield, antioxidant and antimicrobial activities of volatile oil extracted from Trichodesma africanum. MATERIALS AND METHODS Volatile oil was extracted using microwave, ultrasonic, microwave-ultrasonic, and conventional hydrodistillation methods. The extracted oil was evaluated for antioxidant and antimicrobial activities. The antioxidant activity was assessed by 2,2-Diphenyl-1-picrylhydrazyl scavenging assay, whereas the antimicrobial activity was assessed by broth microdilution method. The antimicrobial activity of the volatile oils was examined against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa American type culture collection reference strains, as well as against methicillin-resistant S. aureus (MRSA) and Candida albicans clinical isolates. RESULTS The volatile oil obtained by the four extraction methods in this study exhibited both antioxidant and antimicrobial activities. Among the four extraction methods used, the microwave-ultrasonic method yielded the largest amount (1.8% v/w) and the yield exhibited the highest antioxidant activity in terms of inhibition (91.83% ± 1.1). The minimum inhibitory concentrations for E. coli, P. aeruginosa, S. aureus, MRSA, and C. albicans were 3, 5, 6, 3, and 9, respectively. CONCLUSION Among the extraction techniques used in this study, the microwave-ultrasonic method showed the best results. Moreover, this study suggests that T. africanum volatile oils contain active substances that could potentially be used both as natural preservatives in food and pharmaceutical industries as well as in developing new antimicrobial and antioxidant agents.