Cucurbitane Triterpenoids from the Leaves of Momordica charantia, and Their Cancer Chemopreventive Effects and Cytotoxicities

Abstract

Seventeen cucurbitane-type triterpenoids, 1-17, including six new compounds, (23E)-3β,25-dihydroxy-7β-methoxycucurbita-5,23-dien-19-al (1), (23S*)-3β-hydroxy-7β,23-dimethoxycucurbita-5,24-dien-19-al (6), (23R*)-23-O-methylmomordicine IV (7), (25ξ)-26-hydroxymomordicoside L (8), 25-oxo-27-normomordicoside L (9), and 25-O-methylkaravilagenin D (12), were isolated from a MeOH extract of the leaves of Japanese Momordica charantia. The structures of new compounds were elucidated on the basis of extensive spectroscopic analyses and comparison with literature. Compounds 1-17 were examined for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced with 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells, a known primary screening test for inhibitors of tumor promotion. Four compounds, 1, (23E)-3β,7β-dihydroxy-25-methoxycucurbita-5,23-dien-19-al (2), karavilagenin D (11), and 12, showed potent inhibitory effects on EBV-EA induction with IC(50) values in the range of 242-264 mol ratio/32 pmol TPA. In addition, compounds 1 and 11 exhibited inhibitory effects on skin-tumor promotion in an in vivo two-stage mouse skin carcinogenesis test based on 7,12-dimethylbenz[a]anthracene (DMBA) as initiator, and with TPA as a promoter. Furthermore, upon evaluation of the cytotoxic activities of compounds 1-17 against human cancer cell lines, compounds 2, 5-7, 9, and 14 showed potent activities against HL60 cell line, and compound 2 against SK-BR-3 cell line.

Food prospects and nutraceutical attributes of Momordica species: A potential tropical bioresources – A review

“…In addition, leaves also considered as important sources of triterpenoids. Zhang et al [35] isolated seventeen cucurbitane-type triterpenoids with six new compounds (23E)-3β,25-dihydroxy-7 β-methoxycucurbita-5, In addition, two new charantin group triterpenoids charantin A and charantin B were recently isolated from the leaves of M. charantia [36]. A number of non-specific measures of saponin derivatives also exist in Momordica species.…”

Separation and Identification of Cucurbitane-Type Triterpenoids from Bitter Melon

“…Historically, all parts of the bitter melon plant, from the roots to fruit to seeds, have been used to ameliorate various health conditions; hence, several studies have isolated and characterized CTMs from different parts of the plant. In most previously published reports, extraction of these molecules from plant material was usually carried out using alcohol or an aqueous/alcoholic mixture (21)(22)(23)(24)(25)(26)(27)(28)(29)(30). The extractions were typically performed at room temperature on a mechanical shaker for a period of a day to several weeks (31)(32)(33).…”

“…Another commonly-reported resin used for the separation of CTMs is Sephadex LH-20 (33,44,45). After an initial purification through silica, the resulting extracts were then subjected to various chromatographic techniques using LH-20 and other resins, but principally silica gel (23,25,26,34). Fractions collected from the various chromatographic runs were further separated by high-performance liquid chromatography (HPLC) and molecules were identified based on ultraviolet (UV), infrared (IR), nuclear magnetic resonance (NMR), and mass spectrometry (MS) to elucidate their structures (22,23,27,29).…”

Cucurbitane Triterpenoids from the Fruit Pulp of Momordica charantia and Their Cytotoxic Activity

“…In the course of our research for bioactive secondary metabolites from Taiwanese M. charantia, we had reported the isolation and structure elucidation of twenty-five cucurbitanetype triterpenoids from the MeOH extract of the stems of this plant. [21][22][23][24][25] In the continuing phytochemical investigation on M. charantia, we further identified two new cucurbitane-type triterpenoids, 25-methoxycucurbita-5,23(E)-diene-3b,19-diol (1) and 7b-ethoxy-3b-hydroxy-25-methoxycucurbita-5,23(E)-dien-19-al (2), together with three known triterpenes, 3b,7b,25-trihydroxycucurbita-5,23(E)-dien-19-al (3), 11,26 (23E)-3b-hydroxy-7b,25-dimethoxycucurbita-5,23-dien-19-al (4), 6 and 3b-hydroxy-25-methoxycucurbita-6,23(E)-dien-19,5b-olide (5), 20 from the fruit pulp of M. charantia ( Figure 1). In this paper, we reported the isolation, structure elucidation and cytotoxic activity of compounds 1-5.…”

“…Tissues of this plant have been used not only as a vegetable, but also as a folk medicine for the treatment of diabetes and bitter stomachic in Asian. Several pharmacological investigations have showed that the extracts or compounds of tissues of M. charantia possess cytotoxic, anti-diabetic, and anti-inflammatory activities [1][2][3][4] More than seventy cucurbitane-type triterpenes have been isolated from the fruits, [3][4][5][6][7][8][9][10][11][12][13][14] seeds, 15,16 root, 17 leaves and vines [18][19][20] of M. charantia. In the course of our research for bioactive secondary metabolites from Taiwanese M. charantia, we had reported the isolation and structure elucidation of twenty-five cucurbitanetype triterpenoids from the MeOH extract of the stems of this plant.…”