Bioactivity-guided metabolite profiling of Pistacia chinensis Bunge gall using LC–HRMS/MS

Abstract

Introduction

Pistacia chinensis Bunge (Chinese pistache) is native to central and southern China, Nepal, and East Asia, where it grows in mountain forests and valleys under warm temperate conditions. In traditional Chinese medicine, it is used to treat dysentery, inflammatory disorders, psoriasis, and rheumatism. This study aims to evaluate the bioactivities of various organic extracts derived from P. chinensis Bunge galls.

Methods

We measured the total phenolic content (TPC) and total flavonoid content (TFC) in gall extracts using the Folin-Ciocalteu (FC) and aluminum chloride colorimetric methods. We also performed the DPPH free radical scavenging assay to evaluate antioxidant activity and used the agar well diffusion method to test antimicrobial activity. Additionally, the cytotoxicity of the methanolic extract was assessed with the brine shrimp lethality assay and the MTT assay against MCF-7 and A549 cell lines. Furthermore, to identify metabolites in the methanolic extract, we utilized high-performance liquid chromatography coupled with electrospray ionization-tandem mass spectrometry (HPLC-ESI-HRMS/MS).

Results

Among various extracts, the methanolic extract of gall showed the highest TPC (198.37 ± 0.01 mg GAE/g) and TFC values (70.08 ± 0.01 mg QE/g). Additionally, the methanolic extract demonstrated greater antibacterial and antioxidant activities than other extracts. Based on these findings, the methanolic extract was chosen for cytotoxicity testing. The brine shrimp assay revealed significant toxicity, with an LC₅₀ of 122.65 ± 2.08 µg/mL. Furthermore, the methanolic extract exhibited IC₅₀ values of 10.60 ± 1.25 µg/mL and 24.56 ± 1.01 µg/mL against MCF-7 and A549 cells, respectively. Twenty-three metabolites were identified in the methanolic gall extract via mass spectrometry. To our knowledge, 2′,3,5,6′,7-pentahydroxy flavanone and 13-oxooctadeca-9,11,15-trienoic acid are reported for the first time in this species. This is also the first report on metabolite profiling and cytotoxicity properties of the gall part of P. chinensis Bunge.

Conclusion

Overall, the methanolic gall extract showed greater bioactivities compared to the other organic extracts. These findings indicate that the galls of P. chinensis Bunge could be a promising source of bioactive metabolites for drug lead development.