Identification and antimicrobial activity of two alkaloids from traditional Chinese medicinal plant Tinospora capillipes

Two antimicrobial alkaloids, palmatine and jatrorrhizine, were isolated from tubers of traditional Chinese medicinal plant Tinospora capillipes using activity-guided isolation method and chromatography. Their antimicrobial activity was determined in vitro. The results showed that palmatine and jatrorrhizine had inhibitory activity against plant pathogens Colletotrichum gloeosporioides, Fusarium oxysporum f. sp. niveum, Mycosphaerella sentina, Pestalotia mangiferae, Cercospora kaki, Gymnosporangium haraeanum, Rhizoctonia solani and Colletotrichum graminicola, with the EC50 values of 0.0348–0.8356 g L−1 and 0.0240–0.8649 g L−1, respectively. Palmatine and jatrorrhizine also exhibited inhibition against animal pathogens Bacillus cereus, Bacillus megaterium, Bacillus subtilis, Staphyloccocus aureus, Staphylococcus epidermidi, Micrococcus lysodeikticus, Proteus vulgaris, Salmonella typhi and Escherichia coli, with the MIC values of 0.1–0.8 g L−1 and 0.1–0.6 g L−1, respectively. These results suggested that palmatine and jatrorrhizine showed relatively broad spectrum antimicrobial activity against plant and animal pathogens.

► Two antimicrobial alkaloids palmatine and jatrorrhizine were isolated from Tinospora capillipes.
► Palmatine and jatrorrhizine had inhibitory activity against plant pathogens.
► Palmatine and jatrorrhizine exhibited inhibition against animal pathogens.