Characterization of allelochemicals from the rhizosphere soil of Pinellia ternate (Thnub.) and their inhibition activity on protective enzymes

•Compounds from the rhizosphere soil of Pinellia ternate were isolated and characterized.•Phytotoxicy of the compounds were evaluated and primary allelochemicals were determined.•Phytotoxicy mechanism of allelochemicals were researched.•Possible releasing pathways of allelochemicals were analyzed.