Growth Inhibitory Activity of Acronychia acidula F. Muell. Fruit Extracts Towards Malodour-forming Bacteria

Introduction: Acronychia acidula F. Muell. (lemon aspen, pigeon berry) has been previously recognized for its antimicrobial properties against a broad panel of pathogenic bacteria. This study assessed the effectiveness of A. acidula as an inhibitory agent against bacteria associated with malodour formation. Methodology: A. acidula fruit extracts were prepared using methanol or water as the extraction solvent. Growth inhibition and minimal inhibitory concentrations were determined against C. jeikeium, P. acnes and B. linens through disc diffusion assays. MIC values were quantified to evaluate their efficacies as antimicrobials. Toxicity of each extract was determined using the Artemia franciscana nauplii bioassay. Results: A. acidula aqueous fruit extracts inhibited the growth of B. linens (MIC = 1258 μg/mL), C. jeikeium (MIC = 1630 μg/mL) and P. acnes (MIC = 1455 μg/mL) in the disc diffusion assay. Similarly, the methanolic fruit extracts inhibited the growth of B. linens (MIC = 2608 μg/mL) and C. jeikeium (MIC = 3044 μg/mL), although no growth inhibition of P. acnes was observed. Both aqueous and methanolic A. acidula extracts were nontoxic towards Artemia nauplii (LC50 values of 1872 μg/mL and 1500 μg/mL). Conclusion: A. acidula fruit extracts were non-toxic and also displayed moderate growth inhibitory bioactivity against B. linens, C. jeikeium and P. acnes, highlighting their potential as additives to deodorants.