In Vitro Human Skin Penetration, Antioxidant and Antimicrobial Activity of Ethanol-Water Extract of Fireweed (Epilobium angustifolium L.)

Abstract

Epilobium angustifolium L. is applied as an antiseptic agent in the treatment of skin diseases. However, there is a lack of information on human skin penetration of active ingredients with antioxidative potential. It seems crucial because bacterial infections of skin and subcutaneous tissue are common and partly depend on oxidative stress. Therefore, we evaluated in vitro human skin penetration of fireweed ethanol-water extracts (FEEs) by determining antioxidant activity of these extracts before and after penetration study using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and Folin–Ciocalteu methods. Microbiological tests of extracts were done. The qualitative and quantitative evaluation was performed using gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC-UV) methods. The in vitro human skin penetration using the Franz diffusion chamber was assessed. The high antioxidant activity of FEEs was found. Gallic acid (GA), chlorogenic acid (ChA), 3,4-dihydroxybenzoic acid (3,4-DHB), 4-hydroxybenzoic acid (4-HB), and caffeic acid (CA) were identified in the extracts. The antibacterial activities were found against Serratia lutea, S. marcescens, Bacillus subtilis, B. pseudomycoides, and B. thuringiensis and next Enterococcus faecalis, E. faecium, Streptococcus pneumoniae, Pseudomonas aeruginosa, and P. fluorescens strains. In vitro penetration studies showed the penetration of some phenolic acids and their accumulation in the skin. Our results confirm the importance of skin penetration studies to guarantee the efficacy of formulations containing E. angustifolium extracts.

Epilobium angustifolium L. Extracts as Valuable Ingredients in Cosmetic and Dermatological Products

“…In our study, phenolic acids such as ChA, GA, 4-HB, 3-HB, 3,4-DHB, and CA were identified by HPLC, and GA was found in a considerable amount. Some phenolic acids, like GA, ChA, 3,4-DHB, and CA, were also found in the herbs of E. angustifolium by Zagórska-Dziok et al, Nowak et al, Ruszová et al, and Lasinskas et al [ 3 , 10 , 23 , 24 ], whereas Zagórska-Dziok et al and Shikov et al found the highest GA compared to the other phenolic acids [ 3 , 25 ]. On the other hand, a lower content of GA and ChA in E. angustifolium compared to other polyphenol compounds was identified by Jariene et al [ 22 ].…”

“…On the other hand, Marti-Mesteres et al showed high penetrations of CA through pigskin. However, these authors applied CA as a pure compound dissolved in propylene glycol at the time penetration of 72 h [ 73 ], while, in our previous studies, CA penetrated through human skin from a 70% ( v / v ) ethanol solution [ 10 ]. Ethanol is a promoter of transepidermal transport, which affects the effectiveness of active substance penetration into the skin [ 74 , 75 ].…”

“…For this purpose, a fluorometer kit (Abcam, ab211108, Cambridge, MA, USA) was used. The activity of this enzyme was assessed based on the manufacturer’s instructions and the procedure previously described by Nizioł-Łukaszewska et al [ 10 ]. Analyses were carried out in a black 96-well plate with a clear flat bottom.…”

“…In recent years, there has been a growing interest in this plant in treating skin diseases, where it is used as an ingredient in cosmetic and dermatological preparations. It is mainly due to its antibacterial, anti-inflammatory, and antioxidant properties [ 3 , 10 , 11 ]. For example, Karakaya reports intense wound healing due to the antioxidant effect of E. angustifolium [ 9 ].…”

“…Therefore, it is also essential to select the appropriate vehicle from which the active ingredients contained in the plant extract will be released. In the previous work, we found that some phenolic acids in the ethanolic extract of E. angustifolium penetrated human skin and accumulate in it [ 10 ].…”