Compounds from the root of Pueraria peduncularis (Grah. ex Benth.) Benth. and their antimicrobial effects

BACKGROUND Pueraria peduncularis belongs to the genus Pueraria DC, and has a wide range of medical and agricultural activities. Previous studies have shown that P. peduncularis extracts have broad bioactivities against phytopathogens. In this paper, we systematically studied the fungicidal activity of root methanol extracts and further isolated the active compounds. RESULTS The root methanol extract inhibited the mycelial growth of the five tested phytopathogens to different degrees. Among these phytopathogens, the inhibitory effect was greatest against R. solani, with an EC50 value of 324.72 mg L-1. Eight compounds were subsequently isolated and identified from P. peduncularis. Among them, puercarpan A and medicarpin showed strong fungicidal activity, with MIC values against Rhizoctonia solani of 1.6 and 6.25 mg L-1, respectively. Puercarpan A is a new compound, and its structure was established as (6aR,6bS,11aR)-6b-hydroxy-3-methoxypterocarpan-10-ene-7-one. CONCLUSION The P. peduncularis extracts exhibit high antimicrobial activity against R. solani and have great potential value of P. peduncularis as a fungicide. (c) 2019 Society of Chemical Industry