Flavonoids belong to a large group of polyphenolic compounds that are widely present in plants. Certain flavonoids, including naringenin, have cytoprotective properties. Although the antioxidant effect has long been thought to be a crucial factor accounting for the cellular effects of flavonoids, mitochondrial channels have emerged recently as targets for cytoprotective strategies. In the present study, we characterized interactions between naringenin and the mitochondrial potassium (mitoBKCa and mitoKATP) channels recently described in dermal fibroblasts. With the use of the patch‐clamp technique and mitoplasts isolated from primary human dermal fibroblast cells, our study shows that naringenin in micromolar concentrations leads to an increase in mitoBKCa channel activity. The opening probability of the channel decreased from 0.97 in the control conditions (200 μmol/L Ca2+) to 0.06 at a low Ca2+ level (1 μmol/L) and increased to 0.85 after the application of 10 μmol/L naringenin. Additionally, the activity of the mitoKATP channel increased following the application of 10 μmol/L naringenin. To investigate the effects of naringenin on mitochondrial function, the oxygen consumption of dermal fibroblast cells was measured in potassium‐containing media. The addition of naringenin significantly and dose‐dependently increased the respiratory rate from 5.8 ± 0.2 to 14.0 ± 0.6 nmol O2 × min−1 × mg protein−1. Additionally, a Raman spectroscopy analysis of skin penetration indicated that the naringenin was distributed in all skin layers, including the epidermis and dermis. In this study, we demonstrated that a flavonoid, naringenin, can activate two potassium channels present in the inner mitochondrial membrane of dermal fibroblasts.

The purpose of the research was to obtain new derivatives of natural triterpene lupeol and to evaluate their potential as active substances in the treatment of skin damage. Four new lupeol esters (propionate, succinate, isonicotinate and acetylsalicylate) and lupeol acetate were obtained using an eco-friendly synthesis method. In the esterification process, the commonly used hazardous reagents in this type of synthesis were replaced by safe ones. This unconventional, eco-friendly, method is particularly important because the compounds obtained are potentially active substances in skin care formulations. Even trace amounts of hazardous reagents can have a toxic effect on damaged or irritated tissues. The molecular structure of the esters were confirmed by 1 H NMR, 13 C NMR and IR spectroscopy methods. Their crystal structures were determined using XRD method. To complete the analysis of their characteristics, physicochemical properties (melting point, lipophilicity, water solubility) and biological activity of the lupeol derivatives were studied. Results of an irritant potential test, carried out on Reconstructed Human Epidermis (RHE), confirmed that the synthesized lupeol derivatives are not cytotoxic and they stimulate a process of human cell proliferation. The safety of use for tested compounds was determined in a cell viability test (cytotoxicity detection kit based on the measurement of lactate dehydrogenase activity) for keratinocytes and fibroblasts. The results obtained showed that the modification of lupeol structure improve its bioavailability and activity. All of the esters penetrate the stratum corneum and the upper layers of the dermis better than the maternal lupeol. Lupeol isonicotinate, acetate and propionate were the most effective compounds in a stimulation of the human skin cell proliferation process. This combination resulted in an increase in the concentration of cells of more than 30% in comparison to control samples. The results indicate that the chemical modification of lupeol allows to obtain promising active substances for treatment of skin damage, including thermal, chemical and radiation burns.

Atomic force microscopy (AFM) and fluorescence microscopy was applied to determine the influence of the anti-aging peptides on the morphology and the mechanical properties of keratinocytes. Immortalized human keratinocytes (HaCaT) were treated with two anti-aging bioactive peptides: Acetyl Tetrapeptide-2 and Acetyl Hexapeptide-50 (Lipotec). The AFM measurement of the keratinocyte stiffness were carried after 48 h exposure at an indentation depth of 200 nm. AFM analysis showed increase of the cell stiffness for cells treated with Acetyl Tetrapeptide-2 (P1) in concentration range. Acetyl Hexapeptide-50 (P2) at concentration of 0.05 µg/ml also increased the stiffness of HaCaT cells but at higher concentrations 0.5 and 5 µg/ml cell stiffness was lower as compared to untreated control. Fluorescence microscopy revealed remodeling of actin filaments dependent on the concentration of P2 peptide. The mechanical response of HaCaT cells treated with P2 peptide corresponds to change of transcription level of ACTN1 and SOD2 which activity was expected to be modulated by P2 treatment.

This article presents the results of experiments, which examine cell mechanisms with the goal of confirming the effective action of the active ingredients used in anti‐aging cosmetics. Skin stiffness measurements with the use of an atomic force microscope on two forms of vitamin C (ascorbyl tetraisopalmitate and l‐ascorbic acid) have been presented. The estimated Young's modulus for three types of cells (a control as well as cells treated with two forms of vitamin C) has shown significant differences in the stiffness of the tested cells which was confirmed in the histological staining experiment. The presented results indicate the dependence between collagen synthesis and the stiffness of cells treated with two forms of vitamin C.

INTRODUCTIONAcne vulgaris (AV) is chronic inflammatory disease of sebaceous glands and hair follicles (so-called folliculosebaceous units) characterized by the presence of both non-inflammatory (i.e. microcomedones, closed comedones and open comedones) and inflammatory lesions (papules, pustules and cysts). AV is the most common skin disease in adolescents, although it is seen more and more often in adults, mostly women. It is estimated that 41% of people aged 25 to 40 suffer from acne lesions for at least 3 to 4 months per year (with a marked predominance in women -female: male ratio of 4:1) [1].AV pathogenesis is complex, involving mostly 4 interdependent pathogenic factors: (i) increased a c t i v i t y o f s e b a c e o u s g l a n d s w i t h s e b u m overproduction; (ii) hyperkeratosis of pilosebaceous duct leading to blockage of pilosebaseous units with excess keratin and sebum, causing comedo formation; (iii) colonization of sebaceous glands ducts with anaerobic bacteria Propionibacterium acnes and increased proliferation of aerobic bacteria Staphylococcus epidermidis and lipophilic yeasts Pityrosporum ovale (which cause irritant action due to free fatty acids derived from hydrolysis of sebum triglycerides); (iv) induction of inflammatory processes in the skin. Other factors involved in the formation of acne lesions include: (i) genetic predisposition (probably polygenic or autosomal dominant with variable penetrance) -genetic factors influence density of androgen receptors in sebaceous glands, 5-α reductase activity, seborrhoea intensity and sebaceous glands size [2,3]; (ii) immunological disturbances -excessive ABSTRACT Background: Acne vulgaris (AV) is a common skin disease with characteristic clinical, chronic course and different etiopathogenesis. AV occurs more and more often among adults, especially women. AV, due to the chronic nature of the skin lesions, often requires many months or even long-term treatment and proper skin care both during the period that does not require administration of drugs, as well as during and after pharmacotherapy. The aim of the study was to evaluate the safety and the anti-acne efficacy of a point-gel containing 2% H2O2 and salicylic acid (0.54%), phytic acid (1%), D-panthenol (1%) and vitamin PP (0.012%). Material and Methods: 24 patients with mild to severe AV used the study product containing hydrogen peroxide for 7 days. The condition of skin patients was assessed instrumentally (VISIA) and clinically by a dermatologist, including assessment of skin lesions visibility in the 10-point analogue scale and the number of particular acne lesions. Results: The product was well tolerated. Dermatological evaluation at day 7 showed a significant decrease in the visibility of acne lesions (P=0.0003) and a significant reduction of number of pustules (P=0.002); an insignificant decrease in numbers of papules and comedones was also observed. Instrumental analysis of VISIA showed insignificant reduction in the number and intensity of skin discolorations, epidermal irregulariti...