Isolation of Phomopsolide A and 6(E)-Phomopsolide A as Antimycobacterial Natural Products from an Unidentified Endophyte of the Canadian Medicinal Plant Heracleum maximum.

An extract of an unidentified endophyte from the Canadian medicinal plant Heracleum maximum exhibited a unique metabolomic profile and significant antimycobacterial activity against Mycobacterium tuberculosis H37Ra. Bioassay guided fractionation of the extract led to the isolation of phomopsolide A (1) and 6(E)-phomopsolide A (2). This is the first report of antimycobacterial activity for 1 and 2.