Search for new lead compounds from higher plants

Abstract

Higher plants represent a rich source of new molecules with pharmacological properties, which are lead compounds for the development of new drugs. During the last decades, the renewed interest in investigating natural products has led to the advent of several important drugs, such as the anticancer substances vinblastine, vincristine and taxol, or the antimalarial agent artemisinin. Success in natural products reasearch is conditioned by a careful plant selection, based on various criteria such as chemotaxonomic data, information from traditional medicine, field observations or even random collection.One main strategy in the isolation of new leads consists of the so-called bioactivity-guided isolation, in which pharmacological or biological assays are used to target the isolation of bioactive compounds. One major drawback of this strategy is the frequent isolation of known metabolites. Therefore, hyphenated techniques (LC-UV/DAD, LC-MS, LC-NMR) have been developed, in order to detect as early as possible potential original structures. These compounds can then be tested in various bioassays. Using a combination of hyphenated techniques and bioactivity-guided isolation procedures, a series of new diterpenoic antifungal quinones have been isolated from the African tree, Bobgunnia madagascariensis (Leguminosae) and recently patented for their strong activity and for their potential use in the treatment of systemic mycoses.