tisdag 20 september 2011
torsdag 15 september 2011
J Nat Prod. 2011 Aug 26;74(8):1731-1736. Epub 2011 Jul 29. (8R)-3β,8-Dihydroxypolypoda-13E,17E,21-triene Induces Cell Cycle Arrest and Apoptosis in Treatment-Resistant Prostate Cancer Cells.
Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University , Ulm D-89081, Germany.
Mastic, a resinous exudate from Pistacia lentiscus, has been reported to exhibit selective cytotoxicity against different cancer cell lines. There are, however, no data published correlating distinct mastic-derived compounds with the postulated cytotoxic activity.
- A polypodane-type bicyclic triterpenoid, (8R)-3β,8-dihydroxypolypoda-13E,17E,21-triene (1), was isolated from P. lentiscus oleogum resin. In androgen-independent PC-3 prostate cancer cells, 1 potently inhibited the expression of cyclins D1 and E, but had no effect on the expression of the cyclin kinase inhibitor p21(Waf1/Cip1). Inhibition of the expression of cell cycle-regulating cyclins resulted in cell cycle arrest in the G(o)/G(1) phase, reduction in the number of cells in the S phase, and the triggering of apoptosis, as detected by increased expression of phosphatidylserine on the cell surface and by formation of DNA laddering. In addition, 1 suppressed the formation of prostate cancer colonies in soft agar and inhibited proliferation, angiogenesis, and the growth of prostate tumors xenografted onto chick chorioallantoic membranes without overt systemic toxicity. Taken together, these data show that 1 triggers apoptosis in chemoresistant, androgen-independent human prostate cancer cells in vitro and in vivo. Thus, 1 may serve as a lead compound for targeting so far incurable androgen-insensitive prostate cancer
- (2) MASTIC resiini luokitellaan terpenoidisiin resiineihin:
- LÄHDE 2:
National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, Japan. firstname.lastname@example.org
Simple chromatographic methods were applied to terpenoid resins used as gum bases. Five triterpenoid resins, mastic, dammar resin, olibanum, benzoin gum and elemi resin, and two diterpenoid resins, rosin and copal resin, were separated with normal-phase TLC. Characteristic patterns were observed for all resins. Different samples of the same resin gave identical patterns. The TLC method is a candidate for a simple identification test for terpenoids resins. Samples were then methyl-esterified and analyzed with GC/MS. All resins exhibited characteristic chromatograms for total ion current. Major constituents of all resins were detected. Unique constituents that can be used as indicators were found in every resin. Therefore, GC/MS of methyl-esterified terpenoid resins is a valuable identification method.
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Luonnonresiini mastic on triterpeeninen rakenteeltaan.
Microchemistry and Microscopy Art Diagnostic Laboratory, University of Bologna, Via Guaccimanni 42, 48123 Ravenna, Italy.
This study proposes FTIR spectroscopy in the far-infrared region (FarIR) as an alternative method for the characterisation of natural resins. To this purpose, standards of natural resins belonging to four different categories
(sesquiterpenic, i.e. elemi, shellac;
diterpenic, i.e. colophony, Venice turpentine;
diterpenic with polymerised components, i.e. copal, sandarac;
triterpenic, i.e. mastic and dammar)
used as paint varnishes have been analysed by FarIR spectroscopy in ATR mode. Discrimination between spectral data and repeatability of measurements have been magnified and verified using principal component analysis, in order to verify the effectiveness of the method in distinguishing the four resin categories. The same samples were analysed in the MidIR range, but the spectral differences between the different categories were not evident. Moreover, the method has been tested on historical samples from the painting "La Battaglia di Cialdiran" (sixteenth century) and from a gilded leather (seventeenth century). In the first case, FarIR spectroscopy allowed confirmation of the results obtained by analytical pyrolysis. In the latter, FarIR spectroscopy proved successfully, effective in the identification of the superficial resin layer that could not be detected with the bulk chromatographic analyses.
torsdag 1 september 2011
Hypertension, nitric oxide, oxidants, and dietary plant polyphenols.
Physical Chemistry-PRALIB, School of Pharmacy and Biochemistry, University of Buenos Aires, Junin 956 C1113AAD, Buenos Aires, Argentina.
Fruits and vegetables are key foods whose high ingestion is associated with the improvement of numerous pathological conditions, including hypertension. Such health promoting actions have been increasingly ascribed to the antioxidant characteristics of different polyphenols in fruits and vegetables. Consequently, based on this assumption, many beverages and foods rich in polyphenols, grape, tea, cocoa, and soy products and many of their chemical constituents purified, are being studied both, as antioxidants and antihypertensive agents. This paper reviews the current evidence linking high polyphenol consumption with reductions in blood pressure. Basic chemical aspects of flavanols, flavonols, isoflavones and stilbenes, as possible responsible for the observed effects of those foods on blood pressure are included. Human interventions studies by using grapes and wine, cocoa and chocolate, black and green tea, soy products, and purified compounds ((+)-catequin, quercetin, (-)-epigallocatechin gallate) are summarized. The discussed hypothesis, strongly supported by experimental data in animals, is that by regulating nitric oxide bioavailability, polyphenols present in fruits and vegetables affect endothelial function and as a consequence, blood pressure. Even when data are not definitive and many questions remain open, the whole evidence is encouraging to start considering diets that can provide a benefit to hypertensive subjects, and those benefits will be more significant in people that do not have controlled his/her elevated blood pressure.
- [PubMed - indexed for MEDLINE]
Chocolate: (un)healthy source of polyphenols?
There is recent epidemiological evidence that chocolate consumption may improve vascular health. Furthermore, several small-scale human intervention studies indicate that habitual chocolate intake enhances the production of vasodilative nitric oxide and may lower blood pressure. It is hypothesized that potential beneficial effects of chocolate on vascular health are at least partly mediated by cocoa polyphenols including procyanidins. Based on cell culture studies, molecular targets of chocolate polyphenols are endothelial nitric oxide synthetase as well as arginase. However, human bioavailability studies suggest that the plasma concentrations of cocoa polyphenols are manifold lower than those concentrations used in cultured cells in vitro. The experimental evidence for beneficial vascular effects of chocolate in human interventions studies is yet not fully convincing. Some human intervention studies on chocolate and its polyphenols lack a stringent study design. They are sometimes underpowered and not always placebo controlled. Dietary chocolate intake in many of these human studies was up to 100 g per day. Since chocolate is a rich source of sugar and saturated fat, it is questionable whether chocolate could be recommended as part of a nutrition strategy to promote vascular health.
- PMCID: PMC3040796