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Resveratrol, a polyphenol present in grapes and other edible plants, possesses several important pharmacological activities, including anticancer activity. Nevertheless, its therapeutic use is still limited because of some unfavourable physicochemical and pharmacokinetic properties, mainly, poor cellular uptake and too rapid metabolism resulting in elimination from the body. To meet these drawbacks, some resveratrol conjugates would be useful, which would possess improved stability, uptake and bioavailability than the lead compound, and the ability to release it once it is internalized into the cell. In this paper we report a synthetic strategy which allowed us to obtain new amphiphilic resveratrol derivatives starting from different selectively protected resveratrol phosphoramidites or even from the resveratrol triphosphoramidite. Specifically, resveratrol was conjugated through phosphate bridge(s) to different lipophilic groups related to membrane lipids, such as cholesteryl or diacylglycero moieties. All the new lipoconjugates were tested towards human neuroblastoma SH-SY5Y cells and proved to be significantly more active than resveratrol, with a concentration-dependent activity.

On the basis of a preliminary screening of seven different samples of Sicilian grape pomace, the ‘Nerello Mascalese’ sample NM2 was selected for an ethanol preparative extraction. The defatted NM2 EtOH extract was subjected to DPPH and GAE assays, showing good radical scavenging activity (SC50 = 9.9 μg/mL) and a GAE value of 397.7 mg/g extract. HPLC–DAD analysis of NM2 extract allowed a quantitative determination of the main anthocyanins (AN) and flavonols/flavonol glycosides (FL/FG). Aliquots of the NM2 extract were subjected to three different fractionation protocols (FP1, FP2 and FP3). The fractions were examined by DPPH and GAE assays, and subjected to HPLC–DAD analysis for the quantitative determination of the main AN and FL/FG. FP3 allowed obtaining a polyphenol-enriched fraction with SC50 = 14.8 μg/mL and GAE = 184.1 mg/g of fraction, accounting for only 1.3% in weight of the EtOH extract. Some considerations about the relationship between antioxidant activity and AN/FL/FG HPLC–DAD profiles are also reported.

A weak alkaline solution of 3-hydroxykynurenine was oxidized using potassium ferricyanide. A stable epr signal was recorded, probably arising from a phenoxazine intermediate. A plausible radical mechanism for this reaction is presented.

5‘-O-Lysophosphatidylnucleosides [5‘-O-(1-O-acyl-sn-glycero-3-phosphoryl)nucleosides] were obtained by a two-step chemoenzymatic synthesis. 5‘-O-(sn-Glycero-3-phosphoryl)nucleosides (5‘-GPNs) were first prepared from a phosphoramidite of 1,2-O-isopropylidene-sn-glycerol and appropriately protected nucleosides, applying the phosphoramidite methodology on the solid phase or in solution. In a following step, the regioselective acylation at the C-1 hydroxyl of the glycerol moiety of 5‘-GPNs was achieved by a lipase-catalyzed transacylation with activated fatty acid esters in organic solvent. Some deoxyribo- and ribonucleosides, as well, were converted into the corresponding lysophosphatidyl derivatives utilizing either saturated or unsaturated fatty acid esters with different length alkyl chains. The synthesis was also applied to the preparation of O-(1-O-palmitoyl-sn-glycero-3-phosphoryl) conjugates of Acyclovir and AZT, of potential pharmacological interest.

The relative content of (2S)- and (2R)-naringin in the albedo of pummelo during maturation in the entire season was determined by normal-phase HPLC using Chiralpak IB, a polysaccharide-derived chiral stationary phase, and n-hexane/ethanol doped with 0.5% TFA as mobile phase. A sigmoid curve was obtained showing variation from 95.3% of (2S)-naringin in very immature fruits to 53% in mature fruit samples (2.3 and 14.4cm diameter, respectively). A comparison was made with previous results obtained for grapefruit and sour orange and a tentative explanation of the bitter taste of sour orange is proposed. The Chiralpak IB is much more efficient with respect to the Chiralcel OD used for the other two Citrus species and separation and resolution factors of 1.73 and 9.2, respectively, were achieved. Authentic samples of naringin and neohesperidin were also separated into their C-2 diastereomers with Chiralpak IB and isolation of the pure diastereomers of naringin was accomplished.

The HPLC separation of the enantiomers of six phthalans (1,3-dihydrobenzo[c]furans) synthesized as racemic mixtures from ortho-lithiated aryloxiranes was accomplished in the normal-phase mode using seven polysaccharide-derived and Pirkle-type chiral stationary phases (CSPs) and n-hexane/2-propanol mixtures as mobile phases. Separation and resolution factors up to 1.6 and 4.2, respectively, were obtained. The performances of various CSPs with regard to the same compound were, however, quite different not only between the two types of CSPs but also within the same type (polysaccharide-derived or Pirkle-type). Also diastereomeric pairs of phthalans show different enantioseparation using the same CSP.

Low levels of plasma homocysteine have been found in children and adult populations living in Burkina Faso in association with a low prevalence of coronary heart disease.Based on this finding, the levels of plasma homocysteine and other thiols (cysteine, cysteinylglycine, glutathione) in postmenopausal women living in Burkina Faso were evaluated with the aim of investigating whether age and life conditions influence plasma homocysteine and other thiol levels.It was found that in older postmenopausal women the mean level of homocysteine was higher (16.4+/-6.6 micromol/L) than in fertile women (6.8+/-1.2 micromol/L) and that this increase was correlated with cysteine levels (166.6+/-44.6 micromol/L). While the glutathione level in postmenopausal women was lower (3.6+/-2.3 micromol/L) compared with fertile women (7.0+/-1.7 micromol/L), cysteinylglycine levels were within the normal range (29.9+/-9.3 micromol/L). No correlation was found between homocysteine levels and serum folate, vitamin B(12), vitamin B(6), cystatin C and serum creatinine levels. The older the women were, the higher were their plasma homocysteine levels: levels up to 20.2+/-9.1 micromol/L were found in those70 years old.The elevated levels of homocysteine in the postmenopausal women of Burkina Faso must be viewed as a characteristic of older age and its metabolic consequences.

Background : Plasmodium falciparum utilises the polyamine pathway, essential in proliferation and differentiation, and imposes an oxidative stress on host cell, enhancing the loss of glutathione. Methods : Standard hematological parameters were determined in 40 black African subjects with acute P. falciparum malaria, 30 aged 5–24 months, 5 aged 4–10 years and 5 aged 19–35 years. Plasma homocysteine, cysteine, glutathione and cysteinylglycine levels were measured by HPLC method. Twenty-eight healthy black children (15 aged 6–24 months and 13 aged 3–10 years) and 20 healthy black adults (aged 20–40 years) were also included as controls. Results : Plasma homocysteine levels were higher in all subjects with P. falciparum malaria and correlated positively with the disease severity and number of parasites, but negatively with Hb levels and patient ages. Cysteine level was found higher in all patients and markedly higher in 4–10 year old patients. Cysteinylglycine level was found lower particularly in 19–35 year old patients. Glutathione level was significantly lower in all patients. Conclusions : The elevated level of homocysteine during acute P. falciparum infection suggests an imbalance in the folate cycle, which could be a consequence of the reduced availability of NADPH and Vit B 12 , caused by increased oxidative stress. This may suggest a selection for the C677T MTHFR allele, driven by P. falciparum in sub-Saharan regions. Hence Hcy level could be useful as a predictive parameter of severity, as well as of treatment efficacy.

The fractionation, guided by cell-growth inhibition assay, of the EtOAc crude extract from grape stems of the Sicilian Vitis vinifera variety ‘Nerello Mascalese’ allowed identification of ten constituents, isolated either as pure compounds (1, 3–5, 7–10) or inseparable mixtures (2a-d and 6a-e). The pure constituents were: two triterpenoid acids, oleanolic (1) and betulinic acids (5); daucosterol (7); a stilbenoid, E-resveratrol (3) and its dimer E-ε-viniferin (4); the simple phenol gallic acid (8); and the flavanols catechin (9) and gallocatechin (10). Four 6′- O-acyldaucosterols (2a-d) and five 1,2-di- O-acyl-3- O-β-D-galactopyranosyl glycerols (6a-e) were also identified as inseparable mixtures. All the isolated compounds were subjected to spectroscopic analysis and MTT bioassay on MCF-7 human breast cancer cells. The majority showed growth-inhibitory activity, 5 being the most active (GI50 = 0.57 μM). Compounds 3–5 were also tested on HT-29, U-87-MG and U-373-MG cell lines.

1. 1. Melanosomes from skin and liver of Rana esculenta L. have been isolated and some chemical properties of the relevant melanin and protein components were compared. 2. 2. In both cases the pigments show spectroscopic (ESR) and chemical characteristics similar to those of eumelanins. The melanin content in skin melanosomes is higher than in the liver counterparts. 3. 3. Amino acid patterns of the two protein components are different in their quantitative composition and both are characterized by high levels of glycine and proline. 4. 4. The results as a whole indicate that skin and liver melanosomes from the same animal markedly differ in their chemical composition.

A method for the determination of 2-[(N-phenyl)benzylaminomethyl]-2-imidazoline X H3PO4 (antazoline phosphate) and 2-(1,2,3,4-tetrahydro-1-naphthyl)-2-imidazoline X HCl (tetrahydrozoline hydrochloride) in ophthalmic solution is described. The pharmaceutical preparation is analysed directly by reversed-phase ion-pair high-performance liquid chromatography and the method is very rapid, selective and simple.

Recent literature about stilbene-based analogues of resveratrol (1) has been reviewed, and a total of 94 compounds are reported (see structures 4 – 97), selected either for their promising anti-tumor properties or as comparative terms in SAR studies. As a general outline, these recent literature data confirm the previously reported observation that minimal modification in the nature and position of the substituents on the stilbene nucleus may cause large variations in their biological activity and, more specifically, in their anti-tumor properties. Among the polyhydroxylated stilbenes, it has been established that those with either a catechol or pyrogallol moiety are far better radical scavengers than either 1 or other analogues lacking an ortho-dihydroxy group, and this property was shown to be related to pro-apoptotic activity. In the large majority of cases where couples of E- and Z-isomers were evaluated for either cytotoxic or pro-apoptotic activity, the Z-isomers were significantly more active than their E analogues; nevertheless, a general rule stating that stilbenoids with Z configuration of the double bond display a considerably higher antiproliferative activity than their E-isomers cannot be considered as established. A variety of methoxystilbenes has been reported recently: in many cases these analogues showed either potent antiproliferative and pro-apoptotic activity or strong inhibition of TNFα-induced activation of NF- kB. Globally considered, polymethoxystilbenes are a sub-group of great interest among the resveratrol analogues: these analogues appear worthy of a deeper evaluation also in connection with their potential anti-angiogenic properties. In addition, in vivo studies indicate that methoxystilbenes undergo different metabolic conversion and have a higher bioavailability than resveratrol. The potent activity of some amino- and halogenated stilbenes is undoubtedly worthy of attention, but the toxicity of these compounds to normal cells has rarely been evaluated. In conclusion, the synthesis and evaluation of stilbene-based resveratrol analogues proved to be a highly active field of research and has recently afforded compounds with either cytotoxic or pro-apoptotic activity in the nanomolar range. Nevertheless, the exact structural determinants to optimize the anti-tumor properties of these compounds and details of their mechanism of action remain to be clarified.

3- O-, 3,5-di- O- and 4′- O-phosphoryl derivatives of ( E)-resveratrol have been obtained following a chemoenzymatic strategy. Variedly acylated resveratrol derivatives have been obtained first by exploiting regioselective properties of Pseudomonas cepacea or Candida antarctica lipases in organic solvents. Each acyl-resveratrol was then phosphorylated by the phosphoramidite chemistry protocol and in sequence freed of protective groups, affording the desired O-phosphoryl derivative. Following UV-absorption spectroscopic investigation on the interaction of the newly synthesized compounds with DNA, 4′- O-phosphorylresveratrol exhibited the best binding affinity. As a result of cytotoxicity tests, 3- O-phosphorylresveratrol was more active than resveratrol against DU 145 prostate cancer cells.

An unusual compound (−)-(S)-4-dimethylsulfonio-2-methoxybutyrate, was identified in aqueous—ethanolic extracts of the red alga Rytiphloea tinctoria.

4-Hydroxy- N -methylproline, an unusual amino acid which has been reported in only a few species of higher plants, has been identified in the aqueous extract of the red alga Chondria coerulescens . Spectral features of this compound are discussed in detail.