Holothuria scabra extracts possess anti-oxidant activity and promote stress resistance and lifespan extension in Caenorhabditis elegans

Abstract Holothuria scabra is a sea cucumber that is mostly found in the Indo-Pacific region including Thailand. Extracts from many sea cucumbers possess pharmacological activities proposed to benefit human health. In this study, we investigated the anti-oxidant and anti-ageing activities of extracts from H . scabra by using Caenorhabditis elegans as a model organism. Parts of H . scabra were solvent-extracted and divided into nine fractions including whole body-hexane (WBHE), whole body-ethyl acetate (WBEA), whole body-butanol (WBBU), body wall-hexane (BWHE), body wall-ethyl acetate (BWEA), body wall-butanol (BWBU), viscera-hexane (VIHE), viscera-ethyl acetate (VIEA), and viscera-butanol (VIBU). All fractions of the extracts were tested for anti-oxidant activities by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays and for anti-ageing effects by lifespan assays using C . elegans as a model. The results showed anti-oxidant properties in all fractions with the highest activity shown by the DPPH assay in WBBU (EC 50  = 3.12 ± 0.09 mg/ml), and by the ABTS assay in WBHE (EC 50  = 0.31 ± 0.10 mg/ml). In lifespan assays the highest anti-ageing effect was detected in WBBU- and BWEA-treated C . elegans with increased mean lifespans of 8.12% and 4.77%, respectively. Furthermore, WBBU and BWEA-treated C . elegans exhibited significantly higher resistance against heat shock and paraquat-induced oxidative stresses than controls. By using LC-MS/MS, both extracts were characterized to contain triterpene glycosides as the main bioactive components. To explore mechanisms of H . scabra extracts on longevity and stress resistance, worms with genetic mutations in anti-ageing pathways were analyzed and showed that WBBU and BWEA did not prolong the lifespan of daf-16 , age-1 , sir-2 . 1 , jnk-1 , sek-1 , and osr-1 mutants, suggesting that these genetic pathways are involved in mediating the anti-ageing effects of the H . scabra extracts. Moreover, WBBU and BWEA enhanced the nuclear translocation of the FoxO/DAF-16 transcription factor, and increased mRNA expression of this gene and its downstream targets sod-3 , hsp12 . 3 , and hsp16 . 2 . In conclusion, this study strongly demonstrates anti-oxidant and anti-ageing properties of H . scabra extracts containing triterpene glycosides, which, in the C . elegans model, may be mediated via the insulin/IGF-1 signaling (IIS)-DAF-16 pathway.