Algicidal and antifungal compounds from the roots of Ruta graveolens and synthesis of their analogs

Ethyl acetate extract of Ruta graveolens roots yielded rutacridone epoxide (1) with potent selective algicidal activity towards Oscillatoria perornata, with lowest-complete inhibition concentration, LCIC = 0.1 ppm, 0.3 μM. The absolute stereochemistry of (2) was determined to be 2′(R) and that of (1) to be 2′(R), 3′(R) by CD and NMR analysis.