Therapeutic Potential of Traditional Oriental Medicines in Targeting Tau Pathology: Insights from Cell-free and Cell-based Screening.

BACKGROUND

Traditional Oriental Medicines (TOMs) formulated using a variety of medicinal plants have a low risk of side effects. In previous studies, five TOMs, namely and have been commonly used to treat patients with Alzheimer's disease (AD). However, only a few studies have investigated the effects of these five TOMs on tau pathology.

OBJECTIVE

This study aimed to examine the effect of five TOMs on various tau pathologies, including post-translational modifications, aggregation and deposition, tau-induced neurotoxicity, and tau-induced neuroinflammation.

METHODS

Immunocytochemistry was used to investigate the hyperphosphorylation of tau induced by okadaic acid. In addition, the thioflavin T assay was used to assess the effects of the TOMs on the inhibition of tau K18 aggregation and the dissociation of tau K18 aggregates. Moreover, a water-soluble tetrazolium-1 assay and a quantitative reverse transcription polymerase chain reaction were used to evaluate the effects of the TOMs on tau-induced neurotoxicity and inflammatory cytokines in HT22 and BV2 cells, respectively.

RESULTS

The five TOMs investigated in this study significantly reduced okadaic acid-induced tau hyperphosphorylation. inhibited the aggregation of tau and promoted the dissociation of tau aggregates. and attenuated tau-induced neurotoxicity in HT22 cells. In addition, , and reduced tauinduced pro-inflammatory cytokine levels in BV2 cells.

CONCLUSION

Our results suggest that five TOMs are potential therapeutic candidates for tau pathology. In particular, showed the greatest efficacy among the five TOMs in cell-free and cell-based screening approaches. These findings suggest that is suitable for treating AD patients with tau pathology.