The cytochrome bc1complex (cyt bc1or complex III) is a promising target of numerous antibiotics and fungicides. With an aim to indentify new lead structures for the bc1complex, a series of novel inhibitors were discovered from the natural product karrikinolide for the first time. Extensive screening results suggested variable inhibitory activities of these compounds against succinate-cytochrome reductase [SCR, a mixture of respiratory complex II (SQR) and complex III (the bc1complex)], implying the essential role of a 4-substituted phenyl group for the high potency. Exceptionally, compound 12g...
