Eight new monoterpenoid indole alkaloids, alstoyunines A-H (1-8), along with 17 known analogues, were isolated from Alstonia yunnanensis. The structures of. the new alkaloids were established by means of extensive spectroscopic methods. Alstoyunines C (3), E (5), and F (6) showed selective inhibition of Cox-2 (>75%). Alstoyunine F (6) showed weak cytotoxicity against the human myeloid leukemia HL-60 (IC(50) = 3.89 mu M) and hepatocellular carcinoma SMMC-7721 (IC(50) = 21.73 mu M) cell lines.

Monoterpenoid Indole Alkaloids from Alstonia yunnanensis

By the end of the twentieth century, the interest in natural compounds as probable sources of drugs has declined and was replaced by other strategies such as molecular target-based drug discovery. However, in the recent times, natural compounds regained their position as extremely important source drug leads. Indole-containing compounds are under clinical use which includes vinblastine and vincristine (anticancer), atevirdine (anti-HIV), yohimbine (erectile dysfunction), reserpine (antihypertension), ajmalicine (vascular disorders), ajmaline (anti-arrhythmic), vincamine (vasodilator), etc. Monoterpene Indole Alkaloids (MIAs) deserve the curiosity and attention of researchers due to their chemical diversity and biological activities. These compounds were considered as an impending source of drug-lead. In this review 444 compounds, were identified from six genera belonging to the family Apocynaceae, will be discussed. These genera (Alstonia, Rauvolfia, Kopsia, Ervatamia, and Tabernaemontana, and Rhazya) consist of 400 members and represent 20% of Apocynaceae species. Only 30 (7.5%) species were investigated, whereas the rest are promising to be investigated. Eleven bioactivities, including antibacterial, antifungal, anti-inflammatory and immunosuppressant activities, were reported. Whereas cytotoxic effect represents 47% of the reported activities. Convincingly, the genera selected in this review are a wealthy source for future anticancer drug lead.

Chemical Diversity and Bioactivities of Monoterpene Indole Alkaloids (MIAs) from Six Apocynaceae Genera

Chapter 1 – Alkaloids of the Aspidospermine Group

Publisher Summary This chapter describes characteristic features of the nuclear magnetic resonance (NMR) spectra of alkaloids, illustrated by examples taken predominantly from papers published during the period January 1969–June 1972. In many of these papers, alkaloid structures have been assigned using NMR structure correlations established prior to the period under review and in some cases this work has been included. The classification of the alkaloids into groups follows that adopted in the Chemical Society specialist report on alkaloids. The classification occasionally differs from that in alkaloid texts on the basis of the volume of NMR data available, a relatively small alkaloid group may be allotted a full sub-section and an important family incorporated into a related group. In addition, if NMR spectral similarities between certain alkaloids are great enough then these alkaloids are discussed together even though this necessitates removal of the alkaloid from its “natural” section. S0066410308603282

Nuclear Magnetic Resonance of Alkaloids

Three new monoterpenoid indole alkaloids, (14 alpha,15 alpha)-14,15-epoxyaspidofractinine (1) and maireines A and 13 (2 and 3, resp.), together with 19 known alkaloids, were isolated from the leaves and twigs of Alstonia mairei. The structures of the new compounds were elucidated by 1D- and 2D-NMR spectroscopic methods in combination with MS experiments.

A. Basu

Papers

Structure and absolute stereochemistry of 19-epi-(+)-echitoveniline. A new indole alkaloid of the leaves of Alstonia venenata r.br.