Evaluation of the antinociceptive effect and standardization of Platycladus orientalis (L.) Franco extract

Background: Platycladus orientalis (L.) Franco (PO) has been used in Oriental medicine to treat rheumatism and diarrhea; however, its antinociceptive effects remain unclear. Objective: This study aimed to reveal the antinociceptive effect of the PO extract and standardize this extract in RAW 264.7 cells and mice with monosodium uric acid (MSU)-induced pain. Results: PO extracts were prepared using different ethanol (EtOH) concentrations (0–100%). Thereafter, groups were determined based on the results of the MSU-induced pain model in mice and nitric oxide (NO) assay using lipopolysaccharide (LPS)-induced RAW 264.7 cells. As the methylene chloride (CH₂Cl₂) and ethyl acetate (EtOAc) layers exhibited increasing effects with time, these layers were selected to isolate the major components. The PO extract was standardized using a highly efficient HPLC method, and its antinociceptive effects in a mouse model of MSU-induced gout pain were determined using the von Frey test. The PO extract was found to exhibit antinociceptive effects. Moreover, sample standardization was successfully achieved based on the validation of these compounds. Conclusion: The PO extract exhibited potent dose- and time-dependent antinociceptive effects in an animal model of gout pain; these effects might be mediated by the major compounds of this extract. Collectively, these results suggest that PO can be used as a herbal drug to treat gout-related pain.