Protocatechuic aldehyde from Salvia miltiorrhiza exhibits an anti-inflammatory effect through inhibiting MAPK signalling pathway

BACKGROUND: The aerial parts of Salvia miltiorrhiza, which was considered to be the waste part and discarded during the root harvest, is rich in protocatechuic aldehyde (PAI). This study investigated the health-promoting effects of extracts and PAI from the aerial parts of Salvia miltiorrhiza, including its anti-inflammatory effects and the underlying mechanisms of action in vitro and in vivo. METHOD: Purification of the sample paste of Salvia miltiorrhiza was accomplished using HPLC analysis. TheMTT (Methylthiazolyldiphenyl-tetrazolium bromide) assay was employed to determine the cell viability. The production of inflammatory factors was detected by ELISA assays. The histopathological analysis was used to analyse the lungs and livers of mice treated with PAI. Western blot was performed to reveal the mechanism of PAI in anti-inflammatory. RESULTS: The extracts and PAI from the aerial parts of Salvia miltiorrhiza inhibited TNF-α, IL-6 production and promoted the production of IL-10 in vivo in mice and in vitro in the macrophage cell line RAW264.7. NF-κB and MAPKs kinase phosphorylation were also suppressed by PAI in vivo and in vitro, indicating that PAI exhibited an anti-inflammatory effect. CONCLUSION: These findings suggest that the aerial parts of Salvia miltiorrhiza extract may serve as potential protective agents for inflammatory. SUPPLEMENTARY INFORMATION: Supplementary information accompanies this paper at 10.1186/s12906-020-03090-4.