tazettine and trispheridine

Seven new alkaloids, N-methylhemeanthidine chloride (1), N-methyl-5,6-dihydroplicane (5), O-methylnerinine (6), N-ethoxycarbonylethylcrinasiadine (7), N-ethoxycarbonylpropylcrinasiadine (8), N-phenethylcrinasiadine (9), and N-isopentylcrinasiadine (10), together with eight known alkaloids, hemeanthamin (2), 3-epimacronine (3), (+)-tazettine (4), N-methylcrinasiadine (11), trisphaeridine (12), 5,6-dihydrobicolorine (13), lycorine (14), and nigragillin (15), were isolated from the whole plants of Zephyranthes candida. The structures of the new compounds were established by spectroscopic data interpretation, with single-crystal X-ray diffraction analysis performed on 1. The absolute configuration of 3-epimacronine (3) was determined by single-crystal X-ray diffraction analysis with Cu Kα irradiation. Compounds 1-15 were evaluated for their in vitro cytotoxicity against five human cancer cell lines and the Beas-2B immortalized (noncancerous) human bronchial epithelial cell line. Compounds 1, 2, 9, and 14 exhibited cytotoxicity with IC(50) values ranging from 0.81 to 13 μM with selectivity indices as high as 10 when compared to the Beas-2B cell line.

Topics: Amaryllidaceae Alkaloids; Antineoplastic Agents, Phytogenic; Crystallography, X-Ray; Dioxoles; Drug Screening Assays, Antitumor; Drugs, Chinese Herbal; Humans; Liliaceae; Molecular Conformation; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Phenanthridines

Seven alkaloids were isolated from Sprekelia formosissima, and five from Hymenocallis x festalis. Tazettine, lycorine, haemanthidine and haemanthamine were evaluated for antiproliferative and multidrug resistance (mdr) reversing activity on mouse lymphoma cells. Lycorine, haemanthidine and haemanthamine displayed pronounced cell growth inhibitory activities against both drug-sensitive and drug-resistant cell lines, but did not significantly inhibit mdr-1 p-glycoprotein. Thus, the tested alkaloids are apparently not substrates for the mdr efflux pump. Assays for interactions with DNA and RNA revealed that the antiproliferative effects of lycorine and haemanthamine result from their complex formation with RNA.

Topics: Alkaloids; Amaryllidaceae Alkaloids; Aniline Compounds; Animals; Antineoplastic Agents, Phytogenic; Dioxoles; DNA; Drug Resistance, Multiple; Leukemia L5178; Magnoliopsida; Mice; Molecular Structure; Nucleic Acid Denaturation; Phenanthridines; Plant Stems; RNA, Transfer; Tumor Cells, Cultured; Verapamil