Antidiabetic activities of triterpenoids isolated from bitter melon associated with activation of the AMPK pathway

Four cucurbitane glycosides, momordicosides Q, R, S, and T, and stereochemistry-established karaviloside XI, were isolated from the vegetable bitter melon (Momordica charantia). These compounds and their aglycones exhibited a number of biologic effects beneficial to diabetes and obesity. In both L6 myotubes and 3T3-L1 adipocytes, they stimulated GLUT4 translocation to the cell membrane--an essential step for inducible glucose entry into cells. This was associated with increased activity of AMP-activated protein kinase (AMPK), a key pathway mediating glucose uptake and fatty acid oxidation. Furthermore, momordicoside(s) enhanced fatty acid oxidation and glucose disposal during glucose tolerance tests in both insulin-sensitive and insulin-resistant mice. These findings indicate that cucurbitane triterpenoids, the characteristic constituents of M. charantia, may provide leads as a class of therapeutics for diabetes and obesity.     

Two new cucurbitane triterpenoids from Momordica charantia L.

Two new cucurbitane-type triterpenoids,(23E)-5β,19-epoxycucurbita-6,23,25-triene-3β-ol(1) and(19R,23E)-5/β,19-epoxy- 19-ethoxycucurbita-6,23-diene~3β,25-diol(2),together with three known compounds,have been isolated from the fruit of Momordica charantia L.Their structures were determined on the basis of spectral analysis.Their cytotoxic activity was tested on 5 cancer cell lines,MCF-7,HepG2,Dul45,Colon205 and HL-60 by MTT assay.Compounds 1,3 and 4 showed weak cytotoxicity.     

Two New Cucurbitane Triterpenoids from Immature Fruits of Momordica charantia

Two new cucurbitane triterpenoids, kuguacin X ( 1 ) and kuguaglycoside I ( 2 ), together with three known analogs, were isolated from immature fruits of Momordica charantia. By detailed analysis of IR, NMR, and MS data, acid hydrolysis, and comparison with spectroscopic data of known compounds, the new compounds were determined to be (23E)‐5β,19‐epoxycucurbita‐6,23‐diene‐3β,22ξ,25‐triol ( 1 ) and (23E)‐5β,19‐epoxycucurbita‐6,23‐dien‐19‐on‐3β,25‐diol 3‐O‐β‐D ‐allopyranoside ( 2 ).     

Determination and quantitation of five cucurbitane triterpenoids in Momordica charantia by reversed-phase high-performance liquid chromatography with evaporative light scattering detection

A simple and specific analytical method for the quantitative determination of five cucurbitane-type triterpenoids isolated from the fruit of Momordica charantia is developed. The triterpenoids present in the fruits of Momordica charantia are separated with an acetonitrile (0.1% acetic acid)-water (0.1% acetic acid)-methanol (0.1% acetic acid) gradient at a flow rate of 0.5 mL/min. The high-performance liquid chromatography separation was performed on a Phenomenex C18 reversed-phase column. By using an evaporative light scattering detector, the main triterpenoids of Momordica charantia could be detected at levels as low as 10 microg/mL. The method was validated for precision, repeatability, and accuracy. The relative standard deviation was between 0.6-4.4%. The method was sensitive, quick, and accurate for the determination of main triterpenes and saponins in Momordica charantia, and can be used for quality control of Momordica charantia and its related dietary supplements.     

Hypoglycaemic activity of saponin fraction extracted from Momordica charantia in PEG/salt aqueous two-phase systems

Momordica charantia (family, Cucurbitaceae), commonly known as karela or bitter melon (Japanese name 'Tsurureishi'), is used as a folk medicine in China, the Indian subcontinent and South America. In Chinese traditional medicine, the plant is usually used as a hypoglycaemic and anti-diabetic agent. The hypoglycaemic activity of saponin fraction (SF) extracted from M. charantia in PEG/salt aqueous two-phase systems was studied in this article. Alloxan-induced hyperglycaemic mice were used in the study. The blood glucose, insulin secretion, glycogen synthesis and the body weight of the mice were analysed. At the same time, the sugar tolerance of the normal mice was also determined. After the mice were administered (i.g.) with SF (500 mg kg(-1)), the blood glucose of alloxan-induced hyperglycaemic mice decreased (p < 0.05), the level of insulin secretion and glycogen synthesis of alloxan-induced hyperglycaemic mice elevated (p < 0.05, p < 0.01) and the sugar tolerance of the normal mice was improved. Also, the body weight of the alloxan-induced hyperglycaemic mice was increased gradually. The saponin constituents extracted from M. charantia in an aqueous two-phase extraction system induced significant hypoglycaemic activity in hyperglycaemic and normal mice.     

Cucurbitane triterpenoids from Momordica charantia

Three new cucurbitane-type triterpenoid saponins, 23-O-beta-D-allopyranosyl-5beta,19-epoxycucurbita-6,24-diene-3beta,22(S),23(S)-triol-3-O-beta-D-glucopyranoside (1), 23-O-beta-D-allopyranosyl-5beta,19-epoxycucurbita-6,24-diene-3beta,22(S),23(S)-triol-3-O-beta-D-allopyranoside (2), and 23-O-beta-D-allopyranosyl-5beta,19-epoxycucurbita-6,24-diene-3beta,19(R), 22(S),23(S)-tetraol-3-O-beta-D-allopyranoside (3), named momordicoside M, N, and O, respectively, along with one known saponin momordicoside L (4), were isolated from the fresh fruits of Momordica charantia. The structures of these saponins were elucidated on the basis of chemical properties and spectral data.     

Natural Compound 3β,7β,25-trihydroxycucurbita-5,23(E)-dien-19-al from Momordica charantia Acts as PPARγ Ligand

Momordica charantia is a popular vegetable associated with effective complementary and alternative diabetes management in some parts of the world. However, the molecular mechanism is less commonly investigated. In this study, we investigated the association between a major cucurbitane triterpenoid isolated from M. charantia, 3β,7β,25-trihydroxycucurbita-5,23(E)-dien-19-al (THCB) and peroxisome proliferator activated receptor gamma (PPARγ) activation and its related activities using cell culture and molecular biology techniques. In this study, we report on both M. charantia fruit crude extract and THCB in driving the luciferase activity of Peroxisome Proliferator Response Element, associated with PPARγ activation. Other than that, THCB also induced adipocyte differentiation at far less intensity as compared to the full agonist rosiglitazone. In conjunction, THCB treatment on adipocytes also resulted in upregulation of PPAR gamma target genes expression; AP2, adiponectin, LPL and CD34 at a lower magnitude compared to rosiglitazone’s induction. THCB also induced glucose uptake into muscle cells and the mechanism is via Glut4 translocation to the cell membrane. In conclusion, THCB acts as one of the many components in M. charantia to induce hypoglycaemic effect by acting as PPARγ ligand and inducing glucose uptake activity in the muscles by means of Glut4 translocation.     

Cucurbitane‐Type Triterpenoids from Momordica charantia

The six new cucurbitane‐type triterpenoids 1 – 6 , along with the ten known triterpenoids 7 – 16 , were isolated from the vines and leaves of Momordica charantia. The structures of the new compounds were elucidated as (3β,7β,15β,23E)‐3,7,15,25‐tetrahydroxycucurbita‐5,23‐dien‐19‐al ( 1 ), (3β,7β)‐3,7,22,23‐tetrahydroxycucurbita‐5,24‐dien‐19‐al ( 2 ), (3β,7β)‐3,7,23,24‐tetrahydroxycucurbita‐5,25‐dien‐19‐al ( 3 ), (3β,7β,23S)‐3,7,23‐trihydroxycucurbita‐5,24‐dien‐19‐al 7‐β‐D ‐glucopyranoside ( 4 ), (3β,7β,23E)‐cucurbita‐5,23‐diene‐3,7,19,25‐tetrol 7‐β‐D ‐glucopyranoside ( 5 ), and (3β,7β,23E)‐3,7‐dihydroxy‐25‐methoxy‐cucurbita‐5,23‐dien‐19‐al 3‐β‐D ‐allopyranoside ( 6 ), by extensive analyses of their spectral data, as well as by chemical methods.     

Anti-inflammatory effect of Zingiber cassumunar Roxb. and its active principles.

The present study was carried out to elucidate the anti-inflammatory effect of the methanol extract obtained from the rhizomes of Zingiber cassumunar Roxb. and its active principles. The methanol extract was partitioned between ether and water, and then the ether-soluble fraction was extracted with n-hexane. The n-hexane-soluble fraction was chromatographed and part of the fraction was rechromatographed by silica gel column. Three compounds were isolated from the n-hexane-soluble fraction and the chemical structures of these compounds were identified as (E)-1-(3,4-dimethoxyphenyl)but-1-ene, (E)-1-(3,4-dimethoxyphenyl)butadiene and zerumbone. The anti-inflammatory activity of these fractions was investigated on carrageenin-induced edema in rats, as well as on acetic acid-induced vascular permeability and writhing symptoms in mice. The methanol extract (p.o.) showed both anti-inflammatory activity and analgesic activity. These activities shifted successively to ether-soluble and n-hexane-soluble fractions and to (E)-1-(3,4-dimethoxyphenyl)but-1-ene. These results suggest that the anti-inflammatory action and analgesic action of Zingiber cassumunar is the result of the (E)-1-(3,4-dimethoxyphenyl)but-1-ene that it contains.     

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

Two new cucurbitane‐type triterpenes, 25‐methoxycucurbita‐5,23(E)‐diene‐3β,19‐diol ( 1 ) and 7β‐ethoxy‐3β‐hydroxy‐25‐methoxycucurbita‐5,23(E)‐dien‐19‐al ( 2 ), together with three known cucurbitane‐type triterpenes, 3β,7β,25‐trihydroxycucurbita‐5,23(E)‐dien‐19‐al ( 3 ), (23E)‐3β‐hydroxy‐7β,25‐dimethoxycucurbita‐5,23‐dien‐19‐al ( 4 ), and 3β‐hydroxy‐25‐methoxycucurbita‐6,23(E)‐dien‐19,5β‐olide ( 5 ), were isolated from the fruit pulp of Momordica charantia. The structures of two new compounds were elucidated on the basis of 1D and 2D NMR, MS, IR, optical rotation. Among these isolates, compounds 1 , 2 , and 5 showed slight cytotoxic activity against the SK‐Hep 1 cell line with IC₅₀ values of 33.1, 24.3, and 38.7 μM, respectively.     

Cucurbitane triterpenoids from Momordica charantia and their cytoprotective activity in tert-butyl hydroperoxide-induced hepatotoxicity of HepG2 cells

Two novel pentanorcucurbitane triterpenes, 22-hydroxy-23,24,25,26,27-pentanorcucurbit-5-en-3-one (1) and 3,7-dioxo-23,24,25,26,27-pentanorcucurbit-5-en-22-oic acid (2) together with a new trinorcucurbitane triterpene, 25,26,27-trinorcucurbit-5-ene-3,7,23-trione (3) were isolated from the methyl alcohol extract of the stems of Momordica charantia. The structures of the new compounds were elucidated by spectroscopic methods. Compounds 2 and 3 showed potent cytoprotective activity in tert-butyl hydroperoxide (t-BHP)-induced hepatotoxicity of HepG2 cells.     

Structures of new cucurbitane-type triterpenes and glycosides, karavilagenins and karavilosides, from the dried fruit of Momordica charantia L. in Sri Lanka

Three new cucurbitane-type triterpene called karavilagenins A, B, and C and five new cucurbitane-type triterpene glycosides called karavilosides I, II, III, IV, and V were isolated from the dried fruit of Sri Lanka Momordica charantia L. (Cucurbitaceae) together with two known cucurbitane-type triterpenes, 19(R)-methoxy-5beta,19-epoxycucurbita-6,23-dien-3beta,25-diol and 5,19-epoxycucurbita-6,23-diene-3,25-diol, and nine known cucurbitane-type triterpene glycosides, goyaglycosides-b, -c, and -d, and momordicosides F1, F2, G, I, K, and L. The structures of karavilagenins and karavilosides were elucidated on the basis of chemical and physicochemical evidence.     

New sterols and triterpenoids from four edible mushrooms

Four edible mushrooms, Panellus serotinus, Lepista nuda, Tricholoma matsutake and Naematoloma sublateritium, have been investigated chemically. Two new sterols, 5alpha,9alpha-epidioxy-(22E)-ergosta-7,22-diene-3beta,6alpha-diol (1) and 5alpha,9alpha-epidioxy-(22E)-ergosta-7,22-diene-3beta,6beta-diol (2), have been isolated from Panellus serotinus. Compound 2 was also isolated from Lepista nuda. A new sterol, 3beta,5alpha,9alpha,14beta-tetrahydroxy-(22E)-ergosta-7,22-dien-6-one (3), and compound 2 have been isolated from Tricholoma matsutake. Three new triterpenoids, sublateriols A-C (4-6), have been isolated from Naematoloma sublateritium. The structures of the new compounds were elucidated on the basis of their spectral data.     

A new cucurbitane triterpenoid from Momordica charantia

One new cucurbitane-type triterpenoid saponin, 5b,19-epoxycucurbita-6,23-diene-3b,19,25-triol-3-O-b-D-allopyranoside (1), named momordicoside P was isolated from the fresh fruits of Momordica charantia. The structure of the saponin was elucidated byspectral methods, including 2D-NMR spectra.     

A new pentacyclic cucurbitane glucoside and a new triterpene from the fruits of Gymnopetalum integrifolium

A new pentacyclic cucurbitane glucoside, named aoibaclyin (1) and a new triterpene (2) have been isolated from the EtOH extract of the fruits of Gymnopetalum integrifolium Kurz (Cucurbitaceae), together with three known compounds, bryoamaride (3), 25-O-acetylbryoamaride (4) and beta-sitosterol 3-O-beta-D-glucopyranoside (5). The structures of these compounds were elucidated by spectroscopic analyses.     

Triterpenoids from the roots of Sanguisorba tenuifolia var. Alba

The ethyl acetate soluble fraction from the roots of Sanguisorba tenuifolia was found to have a hypoglucemic effect in alloxan-induced diabetic rats. Two new triterpenoids, identified as 2-oxo-3β,19α-dihydroxyolean-12-en-28-oic acid β-D-gluco-pyranosyl ester (1) and 2α,19α-dihydroxy-3-oxo-12-ursen-28-oic acid β-D-glucopyranosyl ester (4) were isolated from this fraction, along with thirteen known triterpenoids. Their structures were elucidated by chemical and spectroscopic methods. All these compounds demonstrated inhibitory activities against α-glucosidase with IC?? values in the 0.62-3.62 mM range.     

Separation of cucurbitane triterpenoids from bitter melon drinks and determination of partition coefficients using vortex‐assisted dispersive liquid‐phase microextraction followed by UHPLC analysis

A rapid, effective method applying vortex‐assisted liquid–liquid microextraction before ultra‐high performance liquid chromatography with mass spectrometry and evaporative light scattering detection was developed for the analysis of four cucurbitane triterpenoids (momordicoside L, momordicoside K, momordicoside F₂, and 3β,7β,25‐trihydroxy cucurbita‐5,23(E )‐dien‐19‐al) in bitter melon juices. Variables affecting the extraction efficiency including different extraction solvents, volume of extraction solvent, salt amount, acid condition, vortex speed and time were optimized thoroughly. Under the optimum conditions, precision was determined by the intra‐ and inter‐day tests in a range of 1.1–5.7% and 2.9–4.0% (RSD), respectively, with recoveries between 95.7 and 106.1%. The calibration curves showed good linearity with square correlation coefficient of 0.9936–0.9991 (evaporative light scattering detection) and 0.9858–0.9989 (MS). The detection limits ranged from 0.8–1.9 ng/mL (MS) to 3–10 ng/mL (evaporative light scattering detection) for these compounds. Enrichment factors of four target compounds were between 27 and 63 times. The proposed method was also used to determine the apparent solvent/water partition coefficients of analytes within the range of 53–120. The developed method can effectively enrich and quantify cucurbitane triterpenoids from bitter melon drinks.     

Investigation of antiplasmodial efficacy of lupeol and ursolic acid isolated from Ficus benjamina leaves extract

Abstract

This study emphasizes on the investigation of antiplasmodial activity of triterpenoids isolated from Ficus benjamina leaves. An unsaponified fraction of petroleum ether extract of plant leaves was subjected to silica gel column chromatography which led to the isolation of two known triterpenoids; namely ursolic acid and lupeol. These compounds were evaluated for antiplasmodial activity by schizont maturation inhibition assay using 3D7 Plasmodium strains. Both, ursolic acid and lupeol were found to exhibit significant antiplasmodial effect with an IC₅₀ value of 18?µg/ml and 3.8?µg/ml, respectively. This study further confirms the traditional role of Ficus benjamina plant in the treatment of malaria which may be attributed to ursolic acid and lupeol.     

Cucurbitacins from Cayaponia racemosa: isolation and total assignment of 1H and 13C NMR spectra

Two new cucurbitane-type triterpenoids, 2beta,3beta,16alpha,20(R),25-pentahydroxy-9-methyl-19-norlanost-5-en-7,22-dione and 2beta,3beta,16alpha,20(R),25-pentahydroxy-9-methyl-19-norlanost-5-en-7,11,22-trione, were isolated from fruits of Cayaponia racemosa. The total (1)H and (13)C chemical shift assignment of these two closely related compounds is described, making use of one- and two-dimensional NMR techniques.     

Tetracyclic triterpenoids from Melia azedarach, L.—III

From petroleum ether extracts of the bark of M. azedarach four novel tetracyclic triterpenoids have been isolated and characterized to be C₃₀ compounds of the euphane (20R) series. Previously known triterpenoids from Meliaceae have all been 20S compounds. Kulinone 1 is the first known euphane or tirucallane (20S) derivative oxygenated in the D ring; kulactone 2, kulolactone 3 and methyl kulonate 4 are additionally oxygenated in the side chain. Compounds 2 and 3 have a 2-oxa-trans-bicyclo[3,3,0]-octanone structure.