Effects of delayed aging by seed oil from Camellia tenuifolia in Caenorhabditis elegans

Tea seed oil from the seeds of Camellia trees is commonly used as edible oil in Asia. Despite its traditional medical effects, there is insufficient scientific data to support the beneficial effects of tea seed oil to human beings. In this study, the model organism Caenorhabditis elegans was applied to investigate the in vivo delayed aging effects by Camellia tenuifolia seed oil and its underlying mechanisms. The results showed that C. tenuifolia seed oil significantly enhanced the antioxidant activity and extended the longevity in C. elegans under juglone-induced oxidative stress. In addition, C. tenuifolia seed oil significantly increased the lifespan of C. elegans by 12.3 % under normal condition (p < 0.001). Furthermore, the degeneration of age-related behaviors, such as pharyngeal pumping rate and defecation cycle, were significantly attenuated and the accumulation of lipofuscin was significantly decreased during aging process in C. elegans treated with C. tenuifolia seed oil. When C. elegans was pretreated with oleic acid using the concentration corresponding to the content in C. tenuifolia seed oil, the results were similar to aforementioned results in C. tenuifolia seed oil. We further showed that C. tenuifolia seed oil enhanced the translocation of the transcription factor DAF-16/FOXO and increased 1.3-fold mRNA level of daf-16 (p = 0.079), thereby triggering the downstream gene SOD-3 expression. Moreover, the other transcription factor SKN-1/Nrf was shown to translocate to nuclear upon C. tenuifolia seed oil pretreatment, further increasing 1.31-fold mRNA level of skn-1 and 1.45-fold mRNA level of downstream gene gcs-1 to enhance the antioxidant activity (p = 0.002; p < 0.001). In conclusion, our study demonstrated that C. tenuifolia seed oil increased the in vivo antioxidant activity, increased longevity, delayed aging effects, and extended lifespan in C. elegans and oleic acid plays a critical role in the beneficial effects of C. tenuifolia seed oil. Results from this study provide scientific evidence for the health effects of C. tenuifolia seed oil. Therefore, it is suggested that C. tenuifolia seed oil worth further investigation for human health and promoting the agriculture in Taiwan.