Effects of Ulva sp. Extracts on the Growth, Biofilm Production, and Virulence of Skin Bacteria Microbiota: Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes Strains.

Ulva sp. is known to be a source of bioactive compounds such as ulvans, but to date, their biological activity on skin commensal and/or opportunistic pathogen bacteria has not been reported. In this study, the effects of poly- and oligosaccharide fractions produced by enzyme-assisted extraction and depolymerization were investigated, for the first time in vitro, on cutaneous bacteria: Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes. At 1000 µg/mL, poly- and oligosaccharide fractions did not affect the growth of the bacteria regarding their generation time. Polysaccharide Ulva sp. fractions at 1000 µg/mL did not alter the bacterial biofilm formation, while oligosaccharide fractions modified S. epidermidis and C. acnes biofilm structures. None of the fractions at 1000 µg/mL significantly modified the cytotoxic potential of S. epidermidis and S. aureus towards keratinocytes. However, poly- and oligosaccharide fractions at 1000 µg/mL induced a decrease in the inflammatory potential of both acneic and non-acneic C. acnes strains on keratinocytes of up to 39.8%; the strongest and most significant effect occurred when the bacteria were grown in the presence of polysaccharide fractions. Our research shows that poly- and oligosaccharide Ulva sp. fractions present notable biological activities on cutaneous bacteria, especially towards C. acnes acneic and non-acneic strains, which supports their potential use for dermo-cosmetic applications.

Suppressive Effect of Two Cucurbitane-Type Triterpenoids from Momordica charantia on Cutibacterium acnes-Induced Inflammatory Responses in Human THP-1 Monocytic Cell and Mouse Models.

Cutibacterium acnes (formerly Propionibacterium acnes) is one of the major bacterial species responsible for acne vulgaris. Numerous bioactive compounds from Momordica charantia Linn. var. abbreviata Ser. have been isolated and examined for many years. In this study, we evaluated the suppressive effect of two cucurbitane-type triterpenoids, 5ß,19-epoxycucurbita-6,23-dien-3ß,19,25-triol (Kuguacin R; KR) and 3ß,7ß,25-trihydroxycucurbita-5,23-dien-19-al (TCD) on live C. acnes-stimulated in vitro and in vivo inflammatory responses. Using human THP-1 monocytes, KR or TCD suppressed C. acnes-induced production of interleukin (IL)-1ß, IL-6 and IL-8 at least above 56% or 45%, as well as gene expression of these three pro-inflammatory cytokines. However, a significantly strong inhibitory effect on production and expression of tumor necrosis factor (TNF)-α was not observed. Both cucurbitanes inhibited C. acnes-induced activation of the myeloid differentiation primary response 88 (MyD88) (up to 62%) and mitogen-activated protein kinases (MAPK) (at least 36%). Furthermore, TCD suppressed the expression of pro-caspase-1 and cleaved caspase-1 (p10). In a separate study, KR or TCD decreased C. acnes-stimulated mouse ear edema by ear thickness (20% or 14%), and reduced IL-1ß-expressing leukocytes and neutrophils in mouse ears. We demonstrated that KR and TCD are potential anti-inflammatory agents for modulating C. acnes-induced inflammation in vitro and in vivo.

In Vitro and In Vivo Screening of Wild Bitter Melon Leaf for Anti-Inflammatory Activity against Cutibacterium acnes.

Cutibacterium acnes (formerly Propionibacterium acnes) is a key pathogen involved in the development and progression of acne inflammation. The numerous bioactive properties of wild bitter melon (WBM) leaf extract and their medicinal applications have been recognized for many years. In this study, we examined the suppressive effect of a methanolic extract (ME) of WBM leaf and fractionated components thereof on live C. acnes-induced in vitro and in vivo inflammation. Following methanol extraction of WBM leaves, we confirmed anti-inflammatory properties of ME in C. acnes-treated human THP-1 monocyte and mouse ear edema models. Using a bioassay-monitored isolation approach and a combination of liquid-liquid extraction and column chromatography, the ME was then separated into n-hexane, ethyl acetate, n-butanol and water-soluble fractions. The hexane fraction exerted the most potent anti-inflammatory effect, suppressing C. acnes-induced interleukin-8 (IL-8) production by 36%. The ethanol-soluble fraction (ESF), which was separated from the n-hexane fraction, significantly inhibited C. acnes-induced activation of mitogen-activated protein kinase (MAPK)-mediated cellular IL-8 production. Similarly, the ESF protected against C. acnes-stimulated mouse ear swelling, as measured by ear thickness (20%) and biopsy weight (23%). Twenty-four compounds in the ESF were identified using gas chromatograph-mass spectrum (GC/MS) analysis. Using co-cultures of C. acnes and THP-1 cells, ß-ionone, a compound of the ESF, reduced the production of IL-1ß and IL-8 up to 40% and 18%, respectively. ß-ionone also reduced epidermal microabscess, neutrophilic infiltration and IL-1ß expression in mouse ear. We also found evidence of the presence of anti-inflammatory substances in an unfractionated phenolic extract of WBM leaf, and demonstrated that the ESF is a potential anti-inflammatory agent for modulating in vitro and in vivo C. acnes-induced inflammatory responses.