Reversal Potential of Multidrug Antibiotic Resistance in <i>Cutibacterium acnes</i> by Ethanol Extracts of Rhubarb

Cutibacterium acnes (C. acnes) is a major contributor to acne inflammation and exhibits significant antibiotic resistance, but research focusing on reversing this resistance is limited. Rhubarb, a natural plant with known therapeutic effects, shows potential in combating antibiotic resistance, however, no studies have been explored before. The aim of this study was to investigate rhubarb's ability to reverse antibiotic resistance in C. acnes. Strains 11,827 and 6919 were cultured and passaged with 0.019 μg/mL ethanol extract, and antibiotic sensitivity was monitored from passage 0 to 12. The extract effectively reversed antibiotic resistance, and was also confirmed by growth curves and oxidative markers. The impact varied across antibiotics, with the most significant reversal being erythromycin (1000-fold), followed by clindamycin (250-fold), and a weaker effect for tetracycline (2-4-fold). This suggests that the extract has a stronger reversal effect on antibiotics with higher resistance. LC-MS analysis identified flavonoids and heterocyclic compounds were may be key active components, with (-)-epicatechin being the most abundant and crucial for antibacterial and reversal activities. The study suggests a new strategy of using rhubarb ethanol extract as a promising acne treatment with much lower resistance, with vital advantages over conventional antibiotics. These also provide new insights into using herbal plants to combat antibiotic resistance.