Green tea catechins (GTCs) are a group of bioactive polyphenolic compounds found in fresh tea leaves (Camellia sinensis (L.) O. Kuntze). They have garnered significant attention due to their diverse health benefits and potential therapeutic applications, including as antioxidant and sunscreen agents. Human skin serves as the primary barrier against various external aggressors, including pathogens, pollutants, and harmful ultraviolet radiation (UVR). Skin aging is a complex biological process influenced by intrinsic factors such as genetics and hormonal changes, as well as extrinsic factors like environmental stressors, among which UVR plays a pivotal role in accelerating skin aging and contributing to various dermatological conditions. Research has demonstrated that GTCs possess potent antioxidant properties that help neutralize free radicals generated by oxidative stress. This action not only mitigates cellular damage but also supports the repair mechanisms inherent in human skin. Furthermore, GTCs exhibit anti-carcinogenic effects by inhibiting pathways involved in tumor promotion and progression. GTCs have been shown to exert anti-inflammatory effects through modulation of inflammatory signaling pathways. Chronic inflammation is known to contribute significantly to both premature aging and various dermatological diseases such as psoriasis or eczema. By regulating these pathways effectively, GTCs may alleviate symptoms associated with inflammatory conditions. GTCs can enhance wound healing processes by stimulating angiogenesis. They also facilitate DNA repair mechanisms within dermal fibroblasts exposed to damaging agents. The photoprotective properties attributed to GTCs further underscore their relevance in skincare formulations aimed at preventing sun-induced damage. Their ability to screen UV light helps shield underlying tissues from harmful rays. This review paper aims to comprehensively examine the beneficial effects of GTCs on skin health through an analysis encompassing in vivo and in vitro studies alongside insights into molecular mechanisms underpinning these effects. Such knowledge could pave the way for the development of innovative strategies focused on harnessing natural compounds like GTCs for improved skincare solutions tailored to combat environmental stresses faced by the human epidermis.

The light-sensitive albino tea plant can produce pale-yellow shoots with high levels of amino acids which are suitable to process high-quality tea. In order to understand the mechanism of the albino phenotype formation, the changes in the physio-chemical characteristics, chloroplast ultrastructure, chlorophyll-binding proteins, and the relevant gene expression were comprehensively investigated in the leaves of the light-sensitive albino cultivar ‘Huangjinya’ (‘HJY’) during short-term shading treatment. In the content of photosynthetic pigments, the ultrastructure of the chloroplast, and parameters of the photosynthesis in the leaves of ‘HJY’ could be gradually normalized along with the extension of the shading time, resulting in the leaf color transformed from pale yellow to green. BN-PAGE and SDS-PAGE revealed that function restoration of the photosynthetic apparatus was attributed to the proper formation of the pigment-protein complexes on the thylakoid membrane that benefited from the increased levels of the LHCII subunits in the shaded leaves of ‘HJY’, indicating the low level of LHCII subunits, especially the lack of the Lhcb1 might be responsible for the albino phenotype of the ‘HJY’ under natural light condition. The deficiency of the Lhcb1 was mainly subject to the strongly suppressed expression of the Lhcb1.x which might be modulated by the chloroplast retrograde signaling pathway GUN1 (GENOMES UNCOUPLED 1)-PTM (PHD type transcription factor with transmembrane domains)-ABI4 (ABSCISIC ACID INSENSITIVE 4).

Squalene and lanosterol are bioactive compounds with diverse physiological effects, found in relatively high concentrations in tea seed oil. Their levels are significantly influenced by cultivar and fruit maturity. As leaf-color specific tea cultivars gain popularity, parts of them tend to have a higher flower and fruit ratio than green-leaf tea cultivars. However, their fruit characteristics remain underexplored. This study investigated 15 tea cultivars with different leaf colors, analyzing phenotypic changes in seeds during maturation, and examining the variation patterns of squalene and lanosterol. The crude water content, dry kernel content, and oil content were closely related to the maturity and effectively reflected seed development. Lanosterol content showed an overall downward trend with increased maturity. Squalene content fluctuated sharply before the seeds fully matured, but gradually decreased once they were fully matured. At full maturity, leaf-color specific tea cultivars generally exhibited higher concentrations of squalene and lanosterol than those with green leaf.