Enhanced Anti-Aging Properties of Silymarin With a Natural Phytochemical Ratio Over Commercial Formulations

Silymarin, a bioactive mixture widely used in anti-aging cosmetic products, is primarily composed of silybin, silychristin, and silydianin. The relative proportions of these three compounds in milk thistle seeds, the natural source of silymarin, differ significantly from those found in commercially available silymarin formulations. Notably, under natural conditions, silymarin contains a higher proportion of silybin than its commercial formulations.

This study aimed to comparatively evaluate how differences in these ratios affect the anti-aging properties of silymarin and to unveil the underlying mechanism.

We quantified the natural and commercial ratio of silymarin. We measured the cytotoxicity of the natural and commercial silymarin mixtures, as well as individual silybin, silychristin, and silydianin. We studied the matrix metalloproteinases (MMPs) inhibition capacities of natural and commercial silymarin mixtures as a sign of their anti-aging properties. The mechanism of enhanced anti-aging properties was studied by ROS scavenging assay, reducing power assay, pro-inflammatory factor inhibition assay, using natural and commercial silymarins, as well as individual silybin, silychristin, and silydianin. Finally, an anti-wrinkle experiment on human faces was conducted using an emulsion containing natural silymarin.

We demonstrated that silymarin composed of the natural phytochemical ratio exhibits superior anti-aging efficacy compared to silymarin prepared using the "commercial ratio." This finding was evidenced by its greater inhibitory effect on MMPs in human dermal fibroblasts, which are involved in collagen degradation in the dermis. Thus, the natural silymarin mixture was more effective at preventing collagen degradation. Reactive oxygen species (ROS) production, the primary trigger for MMP synthesis, was attenuated more strongly by the natural silymarin mixture, likely due to the higher ROS scavenging capacity of silybin compared to silychristin and silydianin. Notably, although the reducing ability of individual compounds (silybin, silychristin, and silydianin), as well as both natural and commercial silymarin mixtures, was studied, no correlation between reducing power and ROS scavenging capacity was observed. The natural silymarin mixture was also more effective at downregulating tumor necrosis factor-alpha (TNF-α), a key pro-inflammatory cytokine, though it did not affect interleukin-6 expression. This effect was also attributed to the higher anti-TNF-α capacity of silybin compared to that of silychristin and silydianin. Finally, an emulsion containing the natural ratio of silymarin was found to be effective in reducing facial wrinkles.

To our knowledge, this study is the first to unveil the mechanistic basis underlying the superior anti-aging properties of silymarin containing a natural phytochemical ratio over commercial silymarin formulations. These findings are anticipated to be useful in producing better silymarin-based anti-aging cosmetic products.