Antitumor Agents, 112. Emarginatine B, a Novel Potent Cytotoxic Sesquiterpene Pyridine Alkaloid from Maytenus emarginata

Abstract

A new sesquiterpene pyridine alkaloid, emarginatine B [2] has been isolated, along with maytansine [3], from Maytenus emarginata. Emarginatine B showed potent cytotoxicity against human KB cells (ED50 = 0.4 micrograms/ml). Spectral correlations established its structure as a 9-benzoate and C-8 epimer of emarginatine A [1]. The conformational aspect of the latter compound was elucidated by nmr studies, including the use of 2D-nmr techniques and difference nOe methods.

Plant‐Derived Natural Products Research in Drug Discovery

“…The authors also have identified cytotoxic sesquiterpene pyridine alkaloids, including emarginatines B (I7) and F (I8), from M. emarginata (Willd.) Ding Hou (90,91). Recently, new triterpenes were isolated from M. chuchuhuasca R. Hamet and Colas (92), along with sesquiterpenes from the same plant (93).…”

Plant-derived natural product research aimed at new drug discovery

“…M. diversifolia contains the related maytanprine (M6), which shows growth-inhibiting and apoptosis-inducing activities in [132]. The authors also identified cytotoxic sesquiterpene pyridine alkaloids, including emargintines B (M7) and F (M8), from M. emarginata [133,134]. Recently, M. chuchuhuasca yielded new triterpenes [135] and sesquiterpenes [136], and antitumor promoting sesquiterpenes were also isolated from M. cuzooina [137].…”

Analysis of sesquiterpene pyridine alkaloids using ESI–MS/MS: The product ion at m / z 310 formed by an ion–dipole intermediate

“…Sesquiterpene pyridine alkaloids are a large group of highly oxygenated sesquiterpenoids, and are predominantly isolated from the plants of the family Celastraceae [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. These alkaloids have significant biological activities, such as their immunosuppressive [5,15], insect antifeedant, insecticidal [9,16], anti-HIV [6,11,12], antitumor [1,2,17] and antiplasmodial activities [13].…”

“…These alkaloids have significant biological activities, such as their immunosuppressive [5,15], insect antifeedant, insecticidal [9,16], anti-HIV [6,11,12], antitumor [1,2,17] and antiplasmodial activities [13]. Rapid and sensitive analysis for these compounds remain desirable.…”