Search results for "lactone"

Elucidation of the biosynthesis and degradation of allantofuranone by isotopic labelling and fermentation of modified precursors.

2010

Feeding experiments with the ascomycete Allantophomopsis lycopodina indicated that the potent fungistatic allantofuranone is biosynthesized from phenylalanine. Further experiments with synthetic precursors gave evidence that the naturally occurring polyporic acid serves as a key intermediate in the biosynthesis. In addition to the formation of allantofuranone, its abiotic and metabolic degradation were investigated.

Acetogenins from Annonaceae: Recent Progress in Isolation, Synthesis and Mechanisms of Action

2005

Covering: the literature from 1998 to 2004 The aim of the present review is to summarise the knowledge about newly isolated acetogenins (ACGs) in the last six years. It will also report the total syntheses that have allowed either the confirmation or the revision of some structures, together with the biological activities and mechanism of action of such interesting natural products. In fact, of the 417 isolated compounds reviewed, over 176 have been added during the period from 1998 to 2004.

Inhibitory effects on mitochondrial complex I of semisynthetic mono-Tetrahydrofuran acetogenin derivatives

2003

Modifications in the terminal alpha,beta-unsaturated gamma-methyl-gamma-lactone moiety or in the alkyl chain that links this terminal gamma-lactone with the alpha,alpha'-dihydroxylated THF system of the natural mono-tetrahydrofuranic acetogenins, annonacin and annonacinone, led to the preparation of eight semisynthetic derivatives. Their inhibitory effects on mitochondrial complex I is discussed and compared with that of the classical complex I inhibitor, rotenone.

Short and Efficient Chemoenzymatic Synthesis of Goniothalamin.

2004

A high-yielding three-step synthesis of goniothalamin involving an enzymatic kinetic resolution in the presence of vinyl acrylate followed by ring-closing metathesis is discussed.

Peripheral androgen blockade versus glandular androgen suppression in the treatment of hirsutism.

1991

Hirsutism in women is often explained on the basis of abnormal peripheral androgen metabolism. To determine whether serum markers of ovarian, adrenal, or peripheral androgen production may be helpful determinants in the treatment of hirsutism and to compare the efficacy of treatment with dexamethasone or spironolactone, 20 hyperandrogenic hirsute patients were treated for up to 2 years. Eleven women who were selected on the basis of sensitivity to dexamethasone were treated with a daily dose of 0.37 mg dexamethasone and had androgen levels suppressed into the normal range. Although significant (P less than .05), Ferriman-Gallwey scores decreased only by 20%: 14.2 +/- 0.5 to 11.4 +/- 0.6. Ni…

High Pressure Processing Impact on Alternariol and Aflatoxins of Grape Juice and Fruit Juice-Milk Based Beverages.

2021

High-pressure processing (HPP) has emerged over the last 2 decades as a good alternative to traditional thermal treatment for food safety and shelf-life extension, supplying foods with similar characteristics to those of fresh products. Currently, HPP has also been proposed as a useful tool to reduce food contaminants, such as pesticides and mycotoxins. The aim of the present study is to explore the effect of HPP technology at 600 MPa during 5 min at room temperature on alternariol (AOH) and aflatoxin B1 (AFB1) mycotoxins reduction in different juice models. The effect of HPP has also been compared with a thermal treatment performed at 90 °C during 21 s. For this, different juice models, or…

Stereoselective anti aldol reactions of erythrulose derivatives. Functionalized chiral d3 and d4 synthons.

2004

An improved procedure for the synthesis of anti aldols from protected erythrulose derivatives is reported. The preparation of functionalized d3 and d4 synthons with various stereochemical arrays by means of this methodology is described and subsequently applied to a stereoselective formal synthesis of the natural metabolite goniothalesdiol.

Effects of ACE-Inhibitors and Angiotensin Receptor Blockers on Inflammation

2011

The role of inflammation in cardiovascular disease and in hypertensive disease above all, is complex. Several studies confirm that activation of renin-angiotensin-aldosterone system (RAAS), through increase in the production of angiotensin II (Ang II), is closely related to local vascular inflammation. Over the BP lowering effects of anti-hypertensive treatments, several ancillary effects for every class may be found, distinguishing the various drugs from one another. Given the pro-inflammatory effects of Ang II and aldosterone, agents that interfere with the components of RAAS, such as ACE inhibitors, Angiotensin Receptor Blockers (ARBs), and mineralocorticoid receptor antagonists (spirono…

2021

Background: The goal of the treatment of Alport syndrome (AS) is to delay the progression of kidney damage. The current standard of care is the use of Renin Angiotensin Aldosterone System (RAAS) blockers: angiotensin-converting enzyme inhibition (ACEi), angiotensin receptor blockade, and, recently, spironolactone (SP). Aim of the study: the purpose of this retrospective study is to evaluate the efficacy (reduction of proteinuria and changes of glomerular function) and safety of a sequential introduction of RAAS blockers up to a triple RAAS blockade in pediatric proteinuric patients with AS. Methods: in this retrospective study (1995 to 2019), we evaluated proteinuria values in AS patients, …

Asymmetric Synthesis of Spiro-oxindole-ε-lactones through N-Heterocyclic Carbene Catalysis

2018

An unprecedented N-heterocyclic carbene-catalyzed annulation of isatin-derived enals and o-hydroxyphenyl-substituted p-quinone methides as bifunctional reagents has been discovered. The new protocol involves a 1,6-addition of the homoenolate equivalent intermediates to the hydroxy donor-1,6-Michael acceptors and leads to spirocyclic oxindole-ε-lactones in high yields and very good stereoselectivities.