Conophylline is a autophagy inducing[1]vinca alkaloid found in plants of the genus Tabernaemontana.
Among the many functional groups in this molecule is an epoxide: the compound where that ring is replaced with a double bond is called conophyllidine and this co-occurs in the same plants.
History
Conophylline and conophyllidine were first reported in 1993 after isolation from the ethanol extract of leaves of Tabernaemontana divaricata. Their structures were confirmed by X-ray crystallography.[2][3] The class of vinca alkaloids to which these compounds belong also contains vincristine and vinblastine, well-known therapeutic agents for human cancers, so they were candidates for a number of biochemical assays to see if they had useful biological activity. By 1996, conophylline it had been reported to inhibit tumours in rats by its action on Ras-expressing cells.[4] This finding did not lead to a useful drug but the molecule continues to be investigated for its biological properties.[5][6][7]
Fukuyama and coworkers published a total synthesis of conophylline and conophyllidine in 2011. Their strategy was to couple two indoline-containing fragments using a type of Polonovski reaction. The synthesis was challenging owing to the eleven stereogenic centers which have to be controlled. The final products are chiral, and laevorotary.[9][10]
^ abKam, Toh-Seok; Loh, Kah-Yeng; Wei, Chen (1993). "Conophylline and Conophyllidine: New Dimeric Alkaloids from Tabernaemontana divaricata". Journal of Natural Products. 56 (11): 1865–1871. doi:10.1021/np50101a001.
^Saxton, J. Edwin (1996). "Recent progress in the chemistry of the monoterpenoid indole alkaloids". Natural Product Reports. 13 (4): 385–411. doi:10.1039/NP9961300327. PMID7666980.
^Umezawa, K; Taniguchi, T; Toi, M; Ohse, T; Tsutsumi, N; Yamamoto, T; Koyano, T; Ishizuka, M (1996). "Growth inhibition of K-ras-expressing tumours by a new vinca alkaloid, conophylline, in nude mice". Drugs Under Experimental and Clinical Research. 22 (2): 35–40. PMID8879977.
^Sridhar, S. N. C; Seshank, Mutya; Atish, T. Paul (2017). "Bis-indole alkaloids from Tabernaemontana divaricata as potent pancreatic lipase inhibitors: Molecular modelling studies and experimental validation". Medicinal Chemistry Research. 26 (6): 1268–1278. doi:10.1007/s00044-017-1836-7. S2CID23580988.
^Han-Ya, Yuki; Tokuyama, Hidetoshi; Fukuyama, Tohru (2011). "Total Synthesis of (−)-Conophylline and (−)-Conophyllidine". Angewandte Chemie International Edition. 50 (21): 4884–4887. doi:10.1002/anie.201100981. PMID21500330.
^Downer-Riley, Nadale K.; Jackson, Yvette A. (2012). "Highlight syntheses". Annual Reports on the Progress of Chemistry, Section B. 108: 147. doi:10.1039/C2OC90006H.
^Kam, Toh-Seok; Pang, Huey-Shen; Lim, Tuck-Meng (2003). "Biologically active indole and bisindole alkaloids from Tabernaemontana divaricata". Organic & Biomolecular Chemistry. 1 (8): 1292–1297. doi:10.1039/B301167D. PMID12929658.