Anthraquinones and flavanols isolated from the vegetable herb Rumex abyssinicus inhibit motility of Phytophthora capsici zoospores

Many secondary metabolites derived from Rumex extracts exhibited potent activities against a panel of phytopathogens including those of Phytophthora spp. Phytochemical investigation of Rumex abyssinicus has led to the isolation of nine compounds, including one phenolic acid (1), five anthraquinones (2–6) and three flavanols (7–9). Compounds 1, 4, 6–9 are reported here from R. abyssinicus for the first time. The isolated compounds were evaluated for their inhibitory activity against zoospores of the oomycete phytopathogen Phytophthora capsici. Physcion (3) displayed strongest motility inhibitory activity with a MIC value of 15 μg mL− 1, and showed lytic activities against zoospores at 500 μg mL− 1.