# Reversal Potential of Multidrug Antibiotic Resistance in Cutibacterium acnes by Ethanol Extracts of Rhubarb

## TL;DR

Rhubarb ethanol extract can reverse antibiotic resistance in C. acnes, a bacteria linked to acne, offering a promising natural treatment alternative.

## Contribution

This study is the first to demonstrate that rhubarb ethanol extract can reverse multidrug resistance in Cutibacterium acnes.

## Key findings

- Rhubarb ethanol extract reversed antibiotic resistance in C. acnes, confirmed by growth curves and oxidative markers.
- The extract showed a 1000-fold reversal effect on erythromycin resistance and a 250-fold effect on clindamycin resistance.
- Flavonoids and heterocyclic compounds, particularly (-)-epicatechin, were identified as key active components in the extract.

## Abstract

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.

1. Ethanol extract of Rhubarb effectively reversed regular clinical antibiotic resistance, and was confirmed by growth curves and oxidative markers.

2. Reversal effects were observed with erythromycin (1000‐fold), clindamycin (250‐fold) and tetracycline (2–4‐fold).

3. The extract has stronger reversal effects on antibiotics with higher resistance.