Twelve coumarins isolated from plants of the Rutaceae collected in Sri Lanka have been subjected to a mechanism-based anticancer bioassay employing DNA repair-deficient and repair-proficient yeasts. Of these, seselin [10] and xanthyletin [11] were found to be active. Seselin also exhibited moderate cytotoxicity.

Sickle cell anaemia has been affecting Africans for centuries. The management of the disease in the past revolved around the use of herbs by the traditional medical practitioners (1). One such remedy in Nigerian traditional medical practice is the drinking of an aqueous extract of the bark of Adansonia digitata L.(Bombacaceae). This bark was evaluated for its antisickling properties using the method of Adesanya and Sofowora(2). The aqueous and methanolic extracts of the bark were partitioned between water and diethyl ether to give the ether fraction. The aqueous and methanolic extract as well as the ether fraction at various concentrations were incubated with 2 % sodium metabisulphite sickled washed HbSS blood samples, respectively.

Analogs of the potent fecal mutagen fecapentaene-12 have been prepared and tested both for mutagenicity and for their ability to serve as biological precursors of 1. It was found that mutagenicity in three different Salmonella tester strains TA96, TA100, and TA104, decreased rapidly as the number of conjugated double bonds was reduced. The aldehyde 8, analogous to the hydrolysis product of 1, showed only low mutagenicity, even in the aldehyde-sensitive strain TA104. None of the polyenes prepared was able to function as a direct biological precursor of 1 under the conditions employed.

Coumanns from Pleiospermium alatum 91 lished), lanceolatin-B (7), iso-pongaglabol (4), isopongaglabol methyl ether (4), and 3'-methoxypongapin (2), occurring in P. glabra the C-6-H signals appeared around = 7.55-7.63 ppm as double doublets and C-5-H signals at around ö = 7.89-8.20 ppm as doublets.