methyl-jasmonate and tabersonine

Catharanthus roseus (L.) G. Don (Apocynaceae) is a medicinal plant that produces more than 130 alkaloids, with special attention given to the production of the anti-hypertensive monomeric indole alkaloids, serpentine and ajmalicine, and the antitumor dimeric alkaloids, vinblastine and vincristine.. This study evaluated the cytotoxic activity of the indole alkaloid-enriched bioactive extract obtained from suspension cultured-cells of C. roseus elicited with methyl jasmonate (MJ) and cyclodextrins (CDs) in three cell lines: JURKAT E.6 human lymphocytic leukemia, THP-1 human monocytic leukemia and BL 1395 non-tumor human B-cell line.. An indole alkaloid-enriched bioactive extract was obtained from C. roseus cell cultures elicited with MJ and CDs. The indole alkaloids were identified using an HPLC-diode array system coupled to a time-of-flight mass spectrometer using electrospray ionization (ESI) source. The cytotoxic assays were made using the colorimetric assay 2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-S-[(phenylamino)carbonyl]-2 tetrazolium hydroxide (XTT).. Four indole alkaloids were identified (catharanthine, ajmalicine, tabersonine and lochnericine) but only catharanthine and ajmalicine were quantified. The concentration of the indole alkaloid-enriched bioactive extract that inhibited cell growth by 50% was 211 and 210 ng/mL for the JURKAT E.6 and THP-1 cell lines, respectively.. The results confirm that the powerful antitumor activity of this indole alkaloid-enriched bioactive extract is not due to the effect of a single compound but depends on the synergistic action of the four compounds identified.

Topics: Acetates; Antineoplastic Agents, Phytogenic; Catharanthus; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cells, Cultured; Chromatography, High Pressure Liquid; Cyclodextrins; Cyclopentanes; Drug Discovery; Humans; Indole Alkaloids; Inhibitory Concentration 50; Oxylipins; Plant Extracts; Plant Leaves; Quinolines; Secologanin Tryptamine Alkaloids; Spectrometry, Mass, Electrospray Ionization; Vinca Alkaloids

Methyl jasmonate, a chemical inducer of secondary metabolism, was shown to promote tabersonine 2 biosynthesis in hairy root cultures of Catharanthus roseus. Tabersonine 6,7-epoxidase activity was detected in total protein extract of jasmonate-induced hairy root cultures using labeled 14C-tabersonine 2. This enzyme converted tabersonine 2 to lochnericine 3 by selective epoxidation at positions 6 and 7 via a reaction dependent on NADPH and molecular oxygen. Carbon monoxide, clotrimazole, miconazole, and cytochrome C were shown to be strong inhibitors of the enzyme. The activity was found in microsomes, indicating that tabersonine 6,7-epoxidase was a cytochrome P-450-dependent monooxygenase.

Topics: Acetates; Alkaloids; Carbon Monoxide; Catharanthus; Cyclopentanes; Cytochrome P-450 Enzyme System; Cytochromes c; Enzyme Inhibitors; Epoxy Compounds; Hydrolases; Indole Alkaloids; Indoles; Microsomes; NADP; Oxidation-Reduction; Oxidoreductases; Oxygen; Oxylipins; Plant Roots; Quinolines