Journal of Agriculture and Food Research (Jun 2024)
Phytochemicals and antimicrobial properties of Thai edible plant extracts and their prebiotic-like effects
Abstract
In this study, the phytochemicals and antimicrobial activities of ethanolic extracts of Thai edible plants, green tea, red cotton tree flower, fingerroot and ginger were evaluated. The plant extracts were taken for evaluation of antimicrobial activities against Cutibacterium acnes DMST 14916, Staphylococcus epidermidis TISTR 518, and Staphylococcus aureus TISTR 746. The minimum inhibitory concentrations (MICs) of green tea, fingerroot, and ginger extracts against C. acnes DMST 14916 were 3.92, 0.49, and 7.85 mg cm-3, respectively and the minimum bacteriostatic concentrations (MBCs) were 3.92, 0.49, and 7.85 mg cm-3, respectively. The MICs and MBCs of fingerroot extract against S. epidermidis TISTR 518 were 0.12 and 0.49 mg cm-3, respectively, while those against S. aureus TISTR 746 were 0.12 and 0.98 mg cm-3, respectively. Red cotton tree flower extract showed no antimicrobial activity against the acne-causing bacteria. By scanning electron microscopy (SEM) evaluation, the bacterial cells treated with the plant extracts revealed visible shrinkages compared to the smooth cell surfaces of the controls. The phytochemicals in the plant extracts were analysed by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Well-known antimicrobial compounds like azelaic acid, embelin and kaempferol 3-rutinoside-4′-glucoside were identified in all extracts. The cytotoxic effects of the plant extracts on human cell lines were further investigated. The green tea extract was slightly toxic to HaCaT cells found at the initial concentration of 62.5 mg cm-3, but not toxic to MRC-5 cells. The fingerroot and ginger extracts had no cytotoxicity on HaCaT cells, but promoted the MRC-5 cell proliferation. The combination effects of the plant extracts were prebiotic-like and indifferent effects. Regarding all results, the ethanolic extracts of green tea, fingerroot, and ginger could be used individually as natural anti-acne ingredients capable of further product development to improve human skin health.
