Apigenin glycosides from green pepper enhance longevity and stress resistance in Caenorhabditis elegans

Peppers are a rich source of bioactive compounds with several health benefits. However, most of the knowledge about these benefits has been obtained through in vitro studies, and less is known about their in vivo health-promoting and stress resistance effects. Therefore, we hypothesized that the intake of apigenin glycosides (XAp-G) from Xiaomila green pepper (Capsicum frutescens) could protect against stress factors and promote longevity of Caenorhabditis elegans. Synchronized worms were treated with XAp-G and the lifespan and stress resistance were examined. XAp-G treatment strongly enhanced the average lifespan of worms by 23.9% compared with control by reducing the reactive oxygen species (ROS) level. Ultrahigh performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectometry analysis showed that Xiaomila pepper (polyamide fraction) contained significant amount of flavone glycosides with m/z 563.14 (apigenin glycosides). Green fluorescent protein fluorescence and real-time polymerase chain reaction analyses showed that XAp-G-treatment could regulate the expression of anti-aging related genes, including daf-2, daf-16, sod-3, hsp-16.2, skn-1, gst-4, gcs-1, jnk-1, and sir-2.1 in C elegans, thereby promoting the translocation of DAF-16 and SKN-1 into the nucleus. However, it could not extend the lifespan of daf-16, skn-1, and sir-2.1 knocked-down mutants. XAp-G treatment significantly reduced ROS under normal and stress conditions (juglone, hydrogen peroxide), and thereby promotes longevity of C elegans via the insulin/insulin-like growth factor-1 signaling pathway.