Background Grape seed extract (GSE) is rich in polyphenolic compounds, particularly (+)‐catechin (C) and (‐)‐epicatechin (EC). Strong antioxidant activity of these compounds makes GSE to be value‐added to the cosmetics with anti‐aging properties. However, a lack of stability in different environmental conditions makes GSE challenging for the development of photostable cosmetic sunscreen products. Aims To evaluate photoprotective effects of GSE on human dermal fibroblasts irradiated with UVA light and assess photostability of catechins in cream formulations containing GSE alone or in combination with octyl methoxycinnamate (OMC). Methods MTT assay was used to assess protective effects of GSE on fibroblasts irradiated with UVA light. A photostability of C and EC in GSE and in cream formulation containing GSE was investigated using high‐performance liquid chromatography and confirmed by reflection and transmission spectrophotometry using Transpore™ tapes and polymethacrylate (PMMA) plates as substrates. Results High UVA doses damaged fibroblast structure and inhibited their growth. However, GSE increased cell viability and effectively protected them from UVA damage. Photostability of C and EC was achieved by combination of GSE and OMC that also improved absorption capacity of UV filter and increased overall efficacy of formulation. PMMA plates showed better applicability for in vitro photostability testing of sunscreen formulations. However, despite the instability of Transpore® tape under heat from UV exposure, it can still be economically a substrate of alternative choice for screening. Conclusions GSE can be used as an effective and sustainable natural resource for prevention of UV‐induced skin damage providing long‐term protection against premature skin aging.

Background Asian skin undergoing chronological aging, accumulates signs of photoaging mediated by prolonged exposure to ultraviolet (UV) radiation. Although sunscreens are effective in preventing signs of photoaging, polyphenol‐rich extracts, for example, grape seed extract (GSE) can provide additional protection through the broad spectrum of biological activities. Aims To access the effectiveness of a sunscreen formulation containing GSE as an important cosmetic ingredient for the improvement of age‐related changes in Asian skin using noninvasive evaluation techniques. Methods Noninvasive methods were used to assess changes in the biophysical properties corresponding to aging signs including melanin and erythema indices, color parameters of the CIE L*a*b* system, elasticity, and hydration of the forearm skin before and after applying the sunscreen with GSE. In addition, to confirm the effectiveness of the tested product, we compared it with benchmark sunscreen, and a cream base containing either GSE or UV filters. Results Twice‐daily application of sunscreen containing 3% GSE significantly reduced the level of melanin and erythema and improved overall skin tone. The hydration was drastically increased after 3 h of wearing formulation and was maintained relatively high for 5 h. Skin elasticity parameters, including Young's modulus, retraction time, and viscoelasticity, improved in participants of all age categories (35–59 years). Moreover, sunscreen with GSE, as acclaimed by participants, improved overall skin appearance. Conclusions The balancing potential of GSE on the skin, combined with the photoprotective properties of UV filters demonstrated an added value as an anti‐aging agent and proved efficacy for both photo‐ and chronologically‐aged Asian skin.

Background: Sunscreens and catechins from grape seed extract (GSE) are sensitive to various environmental factors and undergo certain changes over time that might affect the effectiveness of the final product. To this date, effects of thermal storage conditions have not been sufficiently addressed to guarantee the long-term stability of sunscreen formulations. Aims:To study the chemical and mechanical accelerated and long-term stability of sunscreen formulation containing GSE at the Climatic Zone IVb conditions. Methods: Stability studies were performed for 6 months for accelerated stability study at 30°C ± 2 and 50°C ± 2, 75 ± 5% relative humidity; and long-term stability study at 5°C ± 5. The quantification of constituents of three formulations: sunscreen with GSE, cream with UV filters only, and cream with GSE only was performed by high-performance liquid chromatography. In vitro spectrophotometry was used to determine changes in sun protection effectiveness through SPF and UVAPF values.Mechanical stability was evaluated by textural and rheological analyzes.Results: All tested formulations were less stable at high-temperature conditions. The contents of catechin (С) and epicatechin (EC) in sunscreen with GSE were reduced to 37% and 50% at 50°C, respectively, whereas UV filters appeared to be stable. However, despite the significant reduction in catechins over time, polyphenols in GSE remained unchanged at different stored conditions. The SPF values and water resistance of sunscreen with GSE were maintained throughout the study. Conclusions:A current in vitro study has shown that sunscreen with GSE is a valueadded anti-aging ingredient in sunscreen formulation because its polyphenolic composition as well as SPF values and water resistance were maintained under all temperature conditions over time.

Abtract Objective In the development of cosmetic products, sensory evaluation is an important step in determining consumer acceptance before it is released on a market but is often time‐consuming and costly. However, correlating sensory characteristics with instrumental parameters using multivariate techniques is a potential way to facilitate the development of cosmetic products. Methods Sunscreen formulations varied in the content of grape seed extract (GSE) and ultraviolet (UV) filters, and benchmark products were characterized using sensory descriptive analysis and instrumental analysis. Principal Component Analysis (PCA) was applied to the panel's performance data to study how well the panelists performed compared to each other and to find an association between rheological and textural instrumental parameters of cream samples. Further, applying Partial Least Squares (PLS) regression analysis, the association between sensory attributes and instrumental parameters was analyzed. In addition, a preference for the sensory properties of the studied sunscreen products that are important for consumers living in Southeast Asia was assessed by PLS. Results In this study, both the sensory and instrumental properties of all tested formulations were described well by PCA. The practicality of PLS was confirmed by an established correlation between sensory attributes from the categories of appearance (glossiness), pick‐up (integrity of shape, firmness, glossiness, stringiness), and after‐feel (glossiness, spreadability, stickiness) with both rheological and textural parameters. Although the instrumental analysis could not completely replace sensory evaluation, a described method applying PLS can be used as an additional cost‐effective and time‐saving method during the development of cosmetic products. Moreover, PLS revealed that sunscreens with a light texture and glossy appearance providing smooth skin after‐feel are likely to be preferred over the thicker formulations having a residual color appearance in Southeast Asia. Conclusion Until a universal model is created, the cosmetics developers and companies can apply a described method of determining sensory properties from the instrumental parameters of their own products. Future studies will be worth exploiting the applicability of the PLS regression model on instrumental datasets predicting sensory characteristics of other sunscreen products.