Polygodial induces inositol phosphate turnover in human neuroblastoma SH-SY5Y cells

Depletion of glutathione as a cause of the promotive effects of polygodial, a sesquiterpene on the production of reactive oxygen species in Saccharomyces cerevisiae

The pungent sesquiterpenoid unsaturated dialdehyde, polygodial, exhibited a strong yeastcidal activity against the cells of Saccharomyces cerevisiae, in which production of reactive oxygen species (ROS) at a significant level could be detected with a fluorescent probe. The production of ROS in polygodial-treated cells was further confirmed by its elimination and the accompanying protection against yeastcidal effects in the presence of antioxidants such as L-ascorbate and alpha-tocopherol (alpha-TOH). Polygodial could accelerate ROS production only in cells of the wild-type grande strain but not in those of the respiratory-deficient petite mutant (rho0), indicating the role of the mitochondrial electron transport chain in the production of ROS. Unlike the case with antimycin A which accelerates ROS production by directly targeting the mitochondrial electron flow, polygodial caused depletion of cytoplasmic and mitochondrial glutathione which functions in estiminating ROS inevitably generated during aerobic growth. Polygodial-mediated depletion of intracellular glutathione was possibly dependent on a direct interaction between its enal moiety and the sulfhydryl group of the cysteine in glutathione by a Michael-type reaction.

Evidence for the involvement of vanilloid receptor in the antinociception produced by the dialdeydes unsaturated sesquiterpenes polygodial and drimanial in rats

This study investigated whether or not the neonatal treatment of rats with the sesquiterpenes polygodial or drimanial could cause persistent antinociception similar to that induced by capsaicin. Rats were injected subcutaneously 48 h after birth with capsaicin (50 mg/kg), polygodial (150 mg/kg), drimanial (150 mg/kg) or vehicle (1ml/kg). Six to eight weeks later, rats were tested in models of nociception. Treatment of rats with capsaicin, polygodial or drimanial produced significant inhibition of the first phase and, to a lesser extent, the second phase of formalin-induced nociception. A significant reduction in Complete Freund's Adjuvant and capsaicin-induced hyperalgesia was observed in the animals neonatally treated with capsaicin, polygodial or drimanial compared with vehicle-treated rats. Moreover, both sesquiterpenes caused inhibition of plasma extravasation induced by injection of capsaicin. The neonatal treatment with capsaicin, polygodial or drimanial significantly decreased [3H]-resiniferatoxin binding sites in the rat spinal cord, but only capsaicin neonatal treatment significantly reduced the expression of TRPV1 in dorsal root ganglia (DRG) when assessed by Western blot. These results extend our previous findings demonstrating that the neonatal treatment of rats with polygodial or drimanial, similar to that reported for capsaicin, produced persistent antinociception in adult animals associated with TRPV1 down-regulation in the spinal cord, but not TRPV1 expression in DRG.

Novel natural vanilloid receptor agonists: new therapeutic targets for drug development

The discovery that compounds lacking a recognizable vanillyl-like motif might act as vanilloids has given new impetus to a search for novel vanilloid receptor agonists and antagonists in compound libraries. The availability of cell lines transfected with a cloned human vanilloid receptor will further expedite this search. In this article, the pharmacological properties of unsaturated dialdehydes and triprenyl phenols that represent two newly discovered chemical classes of vanilloids will be discussed. The existence of vanilloid receptors in several brain nuclei as well as in non-neuronal tissues predicts novel, innovative therapeutic indications for vanilloids. However, these findings also suggest that vanilloids might cause side-effects. An exploration of the uses of unsaturated dialdehydes in indigenous medicine might help identify new therapeutic targets for vanilloids and avoid unwanted actions.