Lactobacillus paraplantarum THG-G10 as a potential anti-acne agent with anti-bacterial and anti-inflammatory activities.

Cutibacterium acnes (formerly Propionibacterium acnes) is the main bacterium targeted for the prevention and medical treatment of acne vulgaris. Lactic acid bacteria (LAB) are a group of microorganisms classified by their ability to produce lactic acid through fermentation. Although the activities of LAB have been studied, their potential anti-acne effects are not well known. Here, Lactobacillus paraplantarum THG-G10, which has anti-bacterial activity against C. acnes, was isolated from traditional Kimchi in Republic of Korea. The anti-acne effects of dried cell-free supernatant of L. paraplantarum THG-G10 (DC-G10) were evaluated by determining its anti-microbial and anti-inflammatory activities. Anti-microbial activity was examined by a broth dilution assay: 25 mg/ml of DC-G10 inhibited the growth of C. acnes KCTC 5012 and KACC 1194; salicylic acid and benzoyl peroxide for acne treatment inhibited the growth of C. acnes KCTC 5012 and KACC 11946 at concentrations of 1.25 and 7.5 mg/ml, respectively; and tea tree oil inhibited the growth of C. acnes KCTC 5012 but not the growth of C. acnes KACC 11946 at 50 mg/ml. Anti-inflammatory activity was evaluated by a nitric oxide (NO) assay: only DC-G10 and ascorbic acid reduced LPS-induced NO production in RAW 264.7 cells in a dose-dependent manner. In addition, the toxicities of erythromycin, salicylic acid, benzoyl peroxide, tea tree oil, and DC-G10 were examined in HaCaT cells and normal human dermal fibroblasts (NHDFs). In these cells, the cytotoxic effects of DC-G10 were weaker than the effects of erythromycin, benzoyl peroxide, and ascorbic acid. Furthermore, scanning electron microscopy revealed that DC-G10 induces deleterious morphological changes in the bacterial cell membrane. These results demonstrate that DC-G10 may be an effective and safe treatment for acne vulgaris.