amarbellisine and lycorine

A practical method for the synthesis of lycorine-type alkaloids with cis-B/C ring structure has been developed. Based on the reactions of aminocyclization, palladium-mediated arylation and especially cyclopropyl ring-opening rearrangement, the synthesis of anhydrocaranine, (±)-γ-lycorane and putative (±)-amarbellisine was accomplished.

Topics: Alkaloids; Amaryllidaceae Alkaloids; Carbon-13 Magnetic Resonance Spectroscopy; Crystallography, X-Ray; Cyclization; Phenanthridines; Proton Magnetic Resonance Spectroscopy

Fifteen Amaryllidaceae alkaloids (1-15) were evaluated for their antiproliferative activities against six distinct cancer cell lines. Several of these natural products were found to have low micromolar antiproliferative potencies. The log P values of these compounds did not influence their observed activity. When active, the compounds displayed cytostatic, not cytotoxic activity, with the exception of pseudolycorine (3), which exhibited cytotoxic profiles. The active compounds showed similar efficacies toward cancer cells irrespective of whether the cell lines were responsive or resistant to proapoptotic stimuli. Altogether, the data from the present study revealed that lycorine (1), amarbellisine (6), haemanthamine (14), and haemanthidine (15) are potentially useful chemical scaffolds to generate further compounds to combat cancers associated with poor prognoses, especially those naturally resistant to apoptosis, such as glioblastoma, melanoma, non-small-cell lung, and metastatic cancers.

Topics: Amaryllidaceae Alkaloids; Antineoplastic Agents, Phytogenic; Apoptosis; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Humans; Molecular Structure; Phenanthridines

Twenty-two lycorine-related compounds were investigated for in vitro antitumor activity using four cancer cell lines displaying different levels of resistance to proapoptotic stimuli and two cancer cell lines sensitive to proapoptotic stimuli. Lycorine and six of its congeners exhibited potency in the single-digit micromolar range, while no compound appeared more active than lycorine. Lycorine also displayed the highest potential (in vitro) therapeutic ratio, being at least 15 times more active against cancer than normal cells. Our studies also showed that lycorine exerts its in vitro antitumor activity through cytostatic rather than cytotoxic effects. Furthermore, lycorine provided significant therapeutic benefit in mice bearing brain grafts of the B16F10 melanoma model at nontoxic doses. Thus, the results of the current study make lycorine an excellent lead for the generation of compounds able to combat cancers, which are naturally resistant to proapoptotic stimuli, such as glioblastoma, melanoma, non-small-cell-lung cancers, and metastatic cancers, among others.

Topics: Actins; Amaryllidaceae Alkaloids; Animals; Antineoplastic Agents; Apoptosis; Cell Movement; Cell Proliferation; Cytoskeleton; Drug Resistance, Neoplasm; Female; Humans; Inhibitory Concentration 50; Maximum Tolerated Dose; Melanoma; Mice; Phenanthridines; Structure-Activity Relationship; Xenograft Model Antitumor Assays