Nicola Uccella

In vitro and in vivo evaluation of caffeic and ferulic acids as topical photoprotective agents

Topically-applied antioxidant drugs represent a successful strategy for protecting the skin against UV-mediated oxidative damage. However, they can afford to the skin a satisfactory photoprotection only if able to permeate through the stratum corneum and thus to reach deeper cutaneous layers. Caffeic and ferulic acids, dissolved in saturated aqueous solutions at pH 3 or 7.2, have been tested for their capability to permeate through excised human skin mounted in Franz cells. At both pH values, ferulic and, at a lower degree, caffeic acids appeared able to permeate through the stratum corneum. The known higher lipophilicity of ferulic acid may explain the fact that it permeates through the stratum corneum better than caffeic acid. However, vehicle pH values proved to have no influence on biophenol skin permeation profile; this observed lack of pH effect may reflect the drug higher concentration attainable in saturated solutions at high pH. On the basis of the findings obtained in these in vitro experiments, we designed the schedule of a series of in vivo experiments, carried out to evaluate the ability of caffeic and ferulic acids to reduce, in healthy human volunteers, UVB-induced skin erythema, monitored by means of reflectance spectrophotometry. Caffeic and ferulic acids, dissolved in saturated aqueous solution pH 7.2, proved to afford a significant protection to the skin against UVB-induced erythema. To conclude, we have confirmed, by means of in vitro and in vivo experiments, that caffeic and ferulic acids may be successfully employed as topical protective agents against UV radiation-induced skin damage; however their skin absorption is not influenced by the pH of the formulation.

Biophenolic components of olives.

The occurrence of biophenolic components in olives provides functional value to the Mediterranean food culture, owing to recognized antioxidant activities of these substances. The concentration of biophenolic compounds in olives are closely linked to texture and organoleptic characteristics of agrifood products, i.e. table olive and olive oil. The concentrations of different biophenolic compounds in olives were investigated in order to develop appropriate procedures for determination of these compounds in fresh and processed table olives and in the olive drupes for olive oil production. Olives from Spain (Hojiblanca cv), Portugal (Douro cv), Greece (Thasos and Conservolia cvs) and Italy (Taggiasca and Cassanese cvs) were analysed. Four different protocols were employed. The first allows for an estimate of the total concentration of simple biophenolic compounds; the second, for soluble compounds and soluble esterified derivatives of these compounds; the third, the qualitative determination of cytoplasmatic soluble biophenolic content; the fourth, determination of soluble, glucosidic, esterified and cell-wall bound biophenols by means of a rapid, though more complex, sequential method, for their accurate evaluation on a structural and quantitative basis. Thus, the experimental procedures yield four different fractions of the biophenolic components of the olive, checked by CC, HPLC and NMR. The experimental results depend on the procedure chosen, the degree of ripeness of the olives, and the environment of the olive cultivars. The composition of each of these fractions can be of valuable information, supporting for table olive growing and olive oil producers in maximising the competitive quality of their products by selecting olive materials whose concentrations of biophenolic compounds can be responsible for beneficial effects on human health.

`In vitro' evaluation of the antioxidant activity and biomembrane interaction of the plant phenols oleuropein and hydroxytyrosol

Abstract Oleuropein and hydroxytyrosol, two phenolic compounds contained in olives and olive oil, are known to possess several biological properties, many of which may be related, partially at least, to their antioxidant and free radical-scavenger ability. Hence, together with their scavenging activity against the stable 1,1-diphenyl-2-picrylhydrazyl radical (DPPH test), we have investigated the antioxidative effect of oleuropein and hydroxytyrosol in a model system consisting of dipalmitoylphosphatidylcholine/linoleic acid unilamellar vesicles (DPPC/LA LUVs) and a water-soluble azo compound as a free radical generator (LP–LUV test). The results obtained were also interpreted in the light of biophenol interactions, studied by differential scanning calorimetry (DSC), with dimyristoylphosphatidylcholine (DMPC) vesicles as a biological membrane model. Our results obtained in the DPPH and LP–LUV tests confirm the good scavenger activity and antioxidant effect of oleuropein and hydroxytyrosol. However, while both compounds exhibit comparable effectiveness in the DPPH test (hydroxytyrosol being slightly more active than oleuropein), oleuropein seems, in the LP–LUV test, a better antioxidant than hydroxytyrosol. Besides oleuropein shows a better antioxidant activity in the membranous system than in homogenous solution. Furthermore, oleuropein, but not hydroxytyrosol, interacts with DMPC vesicles, causing shifts, toward lower values, of the calorimetric peak temperature ( T m ), associated to the gel to liquid-crystal phase transition, typical for DMPC multilayers. The hypothesis will be discussed that hydroxytyrosol can serve as scavenger of aqueous peroxyl radicals near the membrane surface, while oleuropein acts also as a scavenger of chain-propagating lipid peroxyl radicals within the membranes.

Ferulic and caffeic acids as potential protective agents against photooxidative skin damage

The biological properties and, particularly, the antioxidant activity of plant hydroxycinnamic acids, such as caffeic and ferulic acids, are well recognised. This preliminary study was designed to estimate the potential utility of caffeic and ferulic acids to prevent, when topically applied, photooxidative stress in the skin. With this aim we have evaluated the antioxidant activity of ferulic and caffeic acids in two experimental models: (1) the UV radiation-induced peroxidation in phosphatidylcholine (PC) liposomal membranes; (2) the scavenging activity against nitric oxide (a radical involved in oxidative reactions). In addition, given that a suitable percutaneous absorption is an essential requirement for successful topical photoprotective agents, we measured their in vitro permeation through excised human skin. Caffeic and ferulic acids efficiently protected PC liposomes from UV radiation-induced peroxidation and reacted with nitrogen oxides. In addition, caffeic and ferulic acids were able to permeate through the stratum corneum (the main barrier against the penetration of exogenous substances through the skin). Taken together, these findings suggest that caffeic and ferulic acids should be good canditates for successful employment as topical protective agents against UV radiation-induced skin damage. © 1999 Society of Chemical Industry

In vitro antimycoplasmal activity of oleuropein

The activity of oleuropein, a phenolic glycoside contained in olive oil, was investigated in vitro against Mycoplasma hominis, Mycoplasma fermentans, Mycoplasma pneumoniae and Mycoplasma pirum. Oleuropein inhibited mycoplasmas at concentrations from 20 to 320 mg/l. The MICs of oleuropein to M. pneumoniae, M. pirum, M. hominis and M. fermentans were 160, 320, 20 and 20 mg/l, respectively.

Microcomponents of olive oil—III. Glucosides of 2(3,4-dihydroxy-phenyl)ethanol

Abstract The molecular structure of the microcomponents of olive fruit was investigated in order to evidence new molecules which could be transferred to the resulting oil and therefore be typical of olive oil. The three glucosides of 2(3,4-dihydroxy-phenyl)ethanol, 1 , 2 and 3 were isolated together with other glucosides previously identified in Olea europaea . Glucosides 1–3 were detected in the olive oil, there being always present a small quantity of water as an emulsion, together with the aglycone, the 2(3,4-dihydroxy-phenyl)ethanol. The presence of glucosides 1–3 is closely linked with the organoleptic characteristics and to the recognized antioxidant properties of olive oil..

Olive biophenols: functional effects on human wellbeing

Abstract With increasing interest in novel descriptors of hedonic-sensory (HS) and functional (F) quality, scientific documentation of the dietary habits associated with the Mediterranean Aliment Culture (MAC) lifestyle, shows low risk for many chronic diseases. This has been interpreted as the F effect of widespread plant antioxidant intake. The antioxidant and antimicrobial activity of some of the most typical biophenols (BPs) contained in table olives (TOs) and olive oil, such as extra virgin olive oil (EVOO), was revealed through biomimetic experiments on the scavenging effects of chain-propagating lipid peroxyl radicals within membranes, and for human skin protection. Dietary intake of TO and EVOO BPs might lower the risk of degenerative diseases and microbial infections for consumers, Homo consumans ( Hc ). MAC foodstuffs, also referred to as ‘life-stage foods’, could emerge as ‘F products’, engineered to tackle the specific dietary requirements of the aged population.

MODIFIED DIDEOXYNUCLEOSIDES : SYNTHESIS OF 2'-N-ALKYL-3'-HYDROXYALKYL-1',2'-ISOXAZOLIDINYL THYMIDINE AND 5-FLUOROURIDINE DERIVATIVES

Abstract Isoxazolidine nucleosides bearing an hydroxyl group at C3, have been prepared in only three steps, with overall high yields. The synthetic approach is based on the 1,3-dipolar cycloaddition of 3-carboxyalkyl- or acylnitrones to vinyl acetate, followed by condensation with silylated thymine or 5-fluorouracil and NaBH4 reduction.

ANALYSIS BY HPLC-MS/MS OF BIOPHENOLIC COMPONENTS IN OLIVES AND OILS

The aim of this work was to analyze by HPLC-MS-MS natural biophenolic compounds in complex natural samples like olives and olive oils. Eleven benzoic and cinnamic acids, vanillin and other eight biophenolic compounds were studied by liquid chromatography-atmospheric pressure ionization mass spectrometry/mass spectrometry with a Turbo Ion source in the negative mode. To confirm the specific presence, with great sensitivity, of such compounds in olive samples, in brine samples and in extravirgin olive oil the fragmentation of precursor ions into the product species acquisition was used in Multiple Reaction Monitoring (MRM) mode.

HPLC-MS SCREENING OF THE ANTIOXIDANT PROFILE OF ITALIAN OLIVE CULTIVARS

Freeze-dried olive fruits from Italian cultivars such as Carolea, Cassanese, and Coratina were analyzed by HPLC-MS. During different stages of maturation of olive fruits, the biophenolic (antioxidant) composition was examined. Twelve biophenolic compounds, viz. hydroxytyrosol, tyrosol, oleoside 11-methyl ester, demethyloleuropein, verbascoside, demethylligstoside, oleacin, oleuropeindiale, demethyloleuropeindiale, oleuropein, ligstroside, and elenolate were identified by HPLC-MS. Oleuropein, the major olive fruit soluble biophenolic fraction, decreased significantly during fruit maturation and showed significant differences between olive cultivars. Coratina drupes extracted from October month contained a higher amount of biophenols than other mono-cultivar extracted drupes.