Phytochemical study of Tabernaemontana laeta (Apocynaceae)

The Tabernaemontana laeta species is typical of the southeast region of Brazil, also known as “esperta” or “guarana” in the north and northwest of Rio de Janeiro1. It belongs to Apocynaceae family, which is responsible by high bioproduction of monoterpenic indole alkaloids. Tabernaemontana genus contains a large number and variety of monoterpenic indole alkaloid with important quimiotaxonomic value, antitumor, antimicrobial and antihypertensive activities and stimulant of the central nervous system2. This work aims at the isolation and identification of compounds presents in leaves and roots of T. laeta found next to Morro do Itaoca in Campos dos Goytacazes, RJ. The leaves were dried and submitted acid-basic extraction and extracted using dichloromethane. A classic column chromatography was performed in the isolation and purification of the monoterpenic indole alkaloid isovoacangine (Figure 1). This alkaloid had its structure elucidated from the complete analysis of the spectroscopic information provides by 1H and 13C NMR, including two-dimensional experiments (1H-1H-COSY, HSQC, HMBC). According to the literature this alkaloid has a high antileukemic potential, it is effective against human leukemic cells of THP-1 lineage, inducing cell death by apoptosis, with greater efficiency than the drug containing vincristine sulfate as a positive control used in the treatment of leukemia3. This study is in progress, with intentions of isolation and identification other alkaloids from leaves and roots of T. laeta and conducting new biological tests.

References:

(1) Medeiros, Walter L. B. et al. "A new natural quaternary indole slkaloid isolated from Tabernaemontana laeta Mart.(Apocynaceae)”. Journal of the Brazilian Chemical Society, v. 12, n. 3, p. 368-372, 2001;
(2) Verpoorte R. 1998. Alkaloids: Biochemistry, Ecology and Medicinal Applications, In Roberts MF, Wink M, Ed., Plenum Press: New York. 486p;
(3) FIGUEIREDO, Elaine R. et al. “Isolation, identification and antileukemic activity of the monoterpene indole alkaloids from Tabernaemontana salzmannii (A. DC.), Apocynaceae”. Revista Brasileira de Farmacognosia, v. 20, n. 5, p. 675-681, 2010.