Identification of a potent and selective gametocytocidal antimalarial agent from the stem barks of Lophira lanceolata.
Bioorg Chem 2019;
93:103321. [PMID:
31585261 DOI:
10.1016/j.bioorg.2019.103321]
[Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/18/2019] [Accepted: 09/26/2019] [Indexed: 11/20/2022]
Abstract
Bioassay-guided fractionation of the organic extract obtained from stem barks of the African plant Lophira lanceolata has led to the isolation of seven biflavonoids, including the new α'-chlorolophirone E (5) and 5'-chlorolophirone D (6). Among the isolated compounds, the bichalcone lophirone E was identified as a potent gametocytocidal agent with an IC50 value in the nanomolar range and negligible cytotoxicity (selectivity index = 570). Lophirone E proved to be about 100 times more active against P. falciparum stage V gametocytes than on asexual blood stages, thus exhibiting a unique stage-specific activity profile. The isolation of structural analogues allowed to draw preliminary structure-activity relationships, identifying the critical positions on the chemical scaffold of lophirone E.
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