Dark tea extract extends Caenorhabditis elegans lifespan by enhancing antioxidant and ferroptosis resistance

Numerous epidemiological studies have found that tea consumption has an anti-aging and preventive effect on age-related diseases. The question of which tea possesses the most potent anti-aging properties and the underlying mechanisms of these effects remains largely obscure.

To explore which type of tea has the strongest anti-aging activity and its mechanism of action.

The Caenorhabditis elegans (C. elegans) longevity and stress tests were used to evaluate the anti-aging activities of six types of tea. Additionally, ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was employed to compare the differences in anti-aging-related chemical components among these teas. These analyses were conducted to identify the tea with the strongest anti-aging activity and to further explore its underlying molecular mechanisms.

All the extracts of tea (200 μg/mL) prolonged life and enhanced stress resistance. Surprisingly, dark tea (DT) had significant anti-aging efficacy. Furthermore, this study found that anti-aging mechanisms of DT include (a) DT modulated the IGF-1 signaling pathway (IIS), SKN-1 and HSF-1 stress resistance pathway, and the AMPK/SIRT1/FOXO signaling pathway. (b) DT upregulated skn-1 and ftn-1 expression, decreased Fe²⁺ levels, and inhibited ferroptosis. (c) DT preserved the integrity and functionality of mitochondria.

This study demonstrated that DT significantly extended lifespan by enhancing antioxidant capacity, maintaining mitochondrial function and suppressing ferroptosis in C. elegans. These anti-aging effects mediated by multiple mechanisms. Furthermore, the anti-aging properties of DT are partly attributed to its high flavonoid levels.