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Medicinal herbs constitute the cornerstone of traditional medicinal practice worldwide. These herbs are relatively cheap, available and their use depends on ancestral experience.1) Medicinal plants represent a great deal of untapped reservoir of drugs and the structural diversity of their component molecules makes a valuable source of novel lead compounds.2,3) There is a growing interest in the utilization of phytoceuticals because many compounds of plant origin are known to possess important phytoceuticals or nutraceutical traits. Natural product scientists are now intensifying efforts towards scientific evaluation of medicinal plants used in traditional remedies. Pavetta crassipes K. SCHUM (Rubiaceae) is widely distributed in the West African sub-region. The leaf is routinely used in Nigeria for the management of respiratory disorders and hypertension in ethnomedical practice (Azija, personal communication). In Nigeria, the plant commonly known as Gadu (Hausa) and Lolubo (Yoruba) is used for food. The inhibitory effects of Pavetta crassipes on the gastrointestinal and uterine smooth muscles have been studied. 4)Amos et al., 5) also reported the anti-inflammatory and muscle relaxant effects of the aqueous extract of Pavetta crassipes. There are no reports in the literature on the hypotensive activity of Pavetta crassipes. The present study was therefore undertaken to investigate the hypotensive effect of the ethanolic extract of Pavetta crassipes leaves in cats and rats as a scientific rationale for their folkloric use as antihypertensive. MATERIALS AND METHODS

A series of indazole-dione derivatives were synthesized by the 1,3-dipolar cycloaddition reaction of appropriate substituted benzoquinones or naphthoquinones and N-carboalkoxyamino diazopropane derivatives. These compounds were evaluated for their effects on human carbonyl reductase. Several of the analogs were found to serve as substrates for carbonyl reductase with a wide range of catalytic efficiencies, while four analogs display inhibitory activities with IC 50 values ranging from 3 -5 μM. Two of the inhibitors were studied in greater detail and were found to be noncompetitive inhibitors against both NADPH and menadione with K I values ranging between 2 and 11 μM. Computational studies suggest that conformation of the compounds may determine whether the indazole-diones bind productively to yield product or nonproductively to inhibit the enzyme.