Astragalin From Camellia sinensis Flowers Increases Collagen Content Alongside Autophagy-Related Mitochondrial Metabolic Changes in Caenorhabditis elegans.

Collagen, the predominant structural protein in skin, is essential for maintaining elasticity and delaying aging. With age-related collagen depletion, enhancing its biosynthesis, particularly via natural bioactive compounds, has attracted scientific and commercial attention. Here, we investigated the collagen-promoting activity of edible flowers by assessing their matrix metalloproteinase (MMP) inhibition and collagen content change. Among 28 tested flower extracts, Camellia sinensis (CSK) exhibited the strongest MMP inhibition (>75%) and significantly increased collagen content in Caenorhabditis elegans (C. elegans). UHPLC-QE-MS analysis identified astragalin, a polyphenol, as the key active compound, which outperformed controls (vitamin C, VC) by elevating collagen levels via mitophagy activation, adenosine triphosphate/nicotinamide adenine dinucleotide phosphate (ATP/NADPH) modulation, and oxidative stress (reactive oxygen species, ROS) reduction. Pharmacological inhibition of autophagy with chloroquine attenuated the astragalin-associated increase in collagen content. In conclusion, our results support that CSK extract and its active constituent astragalin promote collagen production through mitophagy-mediated NADPH metabolic regulation, offering a novel mechanism of collagen enhancement and highlighting the potential of plant-derived polyphenols in dermatological research.