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Objective: This study explored the impact of a black tea extract obtained through (plant small RNA) PSRTM technology, characterized by its abundance of small molecules, particularly citric acid—an antioxidant and tricarboxylic acid (TCA) cycle contributor—on mitochondrial health. The primary focus was to assess whether this extract could counteract reactive oxygen species (ROS)-induced mitochondrial alterations associated with aging, which lead to impaired mitochondrial function, reduced ATP production, and increased ROS generation. Methods: The PSRTM extraction method was employed to obtain a high content of polyphenols and small molecules, particularly citric acid. Results: In comparison with a conventional extract, the PSRTM extract demonstrated significant enhancements in aconitase activity, an ROS-sensitive enzyme in the TCA cycle, as well as basal respiration and ATP synthesis in fibroblast cells and skin biopsies. Moreover, the PSRTM extract effectively reduced ROS production by safeguarding this critical enzyme within the Krebs cycle and displayed superior capabilities in scavenging free radicals when exposed to UV-induced stress. When administered post-UV exposure, the PSRTM extract protected nuclear DNA by reducing the formation of cyclobutane pyrimidine dimers (CPDs) and promoting DNA repair mechanisms. Furthermore, the extract exhibited beneficial effects on the extracellular matrix, characterized by a reduction in matrix metalloprotease 1 (MMP1) and an increase in fibrillin 1 expression. Conclusions: These findings collectively suggest that the PSRTM extract holds promising antiaging potential, potentially functioning as a mitochondrial nutrient/protector due to its multifaceted benefits on mitochondrial function, nuclear DNA integrity, and the extracellular matrix.

Recent publications describe various skin disorders in relation to phototypes and aging. The highest phototypes (III to VI) are more sensitive to acne, with the appearance of dark spots due to the inflammation induced by Cutibacterium acnes (previously Propionibacterium acnes). Dryness with aging is due to a lower activity of specific enzymes involved in the maturation of lipids in the stratum corneum. To observe and understand these cutaneous issues, tissue engineering is a perfect tool. Since several years, pigmented epidermis with melanocytes derived from specific phototypes allow to develop in vitro models for biological investigations. In the present study, several models were developed to study various skin disorders associated with phototypes and aging. These models were also used to evaluate selected ingredients’ ability to decrease the negative effects of acne, inflammation, and cutaneous dryness. Hyperpigmentation was observed on our reconstructed pigmented epidermis after the application of C. acnes, and pollutant (PM10) application induced increased inflammatory cytokine release. Tissue engineering and molecular biology offer the capability to modify genetically cells to decrease the expression of targeted proteins. In our case, GCase was silenced to decrease the maturation of lipids and in turn modify the epidermal barrier function. These in vitro models assisted in the development of ethnic skin-focused cosmetic ingredients.