quinine and fangchinoline

An alkaloid extract derived from the roots of Cyclea barbata demonstrated cytotoxic and antimalarial activities, and five bisbenzylisoquinoline alkaloids, (+)-tetrandrine [1], (-)-limacine [2], (+)-thalrugosine [3], (+)-homoaromoline [4], and (-)-cycleapeltine [5], were isolated as the active principles. The complete and unambiguous assignments of the 1H- and 13C-nmr data of these substances were made by 1D and 2D nmr techniques (COSY, phase-sensitive ROESY, HETCOR, and FLOCK).

Topics: Alkaloids; Animals; Antimalarials; Antineoplastic Agents, Phytogenic; Asia; Benzylisoquinolines; Cell Survival; Drug Screening Assays, Antitumor; Erythrocytes; Humans; In Vitro Techniques; KB Cells; Leukemia P388; Magnetic Resonance Spectroscopy; Plants, Medicinal; Plasmodium falciparum; Spectrophotometry, Ultraviolet; Tumor Cells, Cultured

(+)-2-N-Methyltelobine [1], a new alkaloid, together with twelve known bisbenzylisoquinolines, was isolated from the tubers of Stephania erecta. The structure determination and the complete 1H- and unambiguous 13C-nmr assignments of 1 were obtained through extensive use of several 1D and 2D nmr techniques. All alkaloids inhibited the growth of cultured Plasmodium falciparum strains D-6 and W-2 and displayed nonselective cytotoxicity with a battery of cultured mammalian cells. These data were used for the calculation of selectivity indices. Relative to known antimalarial agents, these bisbenzylisoquinoline alkaloids do not appear to be promising clinical candidates at the present time.

Topics: Alkaloids; Animals; Antimalarials; Antineoplastic Agents, Phytogenic; Benzylisoquinolines; Cell Survival; Drug Screening Assays, Antitumor; Erythrocytes; Female; Humans; In Vitro Techniques; Male; Mice; Plants, Medicinal; Plasmodium falciparum; Thailand; Tumor Cells, Cultured