Chemical composition, antimicrobial and anti-inflammatory activities of the essential oil from Maqian (Zanthoxylum myriacanthum var. pubescens) in Xishuangbanna, SW China

Abstract

Ethnopharmacological relevance: Maqian (Zanthoxylum myriacanthum var. pubescens Huang) is widely consumed as an indigenous remedy for digestive disorders, detoxification, detumescence and analgesia by the ethnic groups in Xishuangbanna, SW China. A related species, Huajiao (Zanthoxylum schinifolium Sieb. et Zucc.), has similar uses in traditional Chinese medicine. We aimed to scientifically validate the traditional uses by investigating and comparing the chemical composition, antimicrobial and anti-inflammatory activities of the essential oils of Maqian and Huajiao.

Materials and methods: Essential oils were collected from the fruits of Maqian and Huajiao by simultaneous distillation extraction and identified by gas chromatography-mass spectrometry (GC-MS) analysis. To assess antimicrobial activity, the minimum inhibitory and bactericidal concentrations (MIC and MBC) against 7 microbial strains, including 5 food-borne pathogens, were evaluated by serial dilution with a standardized microdilution broth methodology. For anti-inflammatory activity, the cell viability and nitric oxide (NO) production were determined on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells by MTS assay and the Griess reagent system, respectively.

Results: The essential oil from Maqian is rich in limonene (67.06%) and has strong antimicrobial activity against the tested pathogens and spoilage organisms, with MIC ranging from 64 to1024µg/ml and MBC ranging from 64 to 2048µg/ml. It also showed anti-inflammatory activity by significantly inhibiting nitric oxide (NO) production induced by LPS in RAW 264.7 cells at 0.04‰ without effects on cell viability. Furthermore, it showed relatively stronger antimicrobial and anti-inflammatory activities than the essential oil from Huajiao.

Conclusions: Our findings not only justify the use of Maqian as an indigenous remedy for digestive disorders, detoxification, detumescence and analgesia, but also suggest that it could be promoted as a preferred substitute for Huajiao.

Keywords: Anti-inflammatory; Antimicrobial; Essential oil; Xishuangbanna; Zanthoxylum myriacanthum var. pubescens.