Epidemiological studies have revealed that a diet rich in plant-derived foods has a protective effect on human health. Identifying bioactive dietary constituents is an active area of scientific investigation that may lead to new drug discovery. Kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is a flavonoid found in many edible plants (e.g. tea, broccoli, cabbage, kale, beans, endive, leek, tomato, strawberries and grapes) and in plants or botanical products commonly used in traditional medicine (e.g. Ginkgo biloba, Tilia spp, Equisetum spp, Moringa oleifera, Sophora japonica and propolis). Some epidemiological studies have found a positive association between the consumption of foods containing kaempferol and a reduced risk of developing several disorders such as cancer and cardiovascular diseases. Numerous preclinical studies have shown that kaempferol and some glycosides of kaempferol have a wide range of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, cardioprotective, neuroprotective, antidiabetic, anti-osteoporotic, estrogenic/antiestrogenic, anxiolytic, analgesic and antiallergic activities. In this article, the distribution of kaempferol in the plant kingdom and its pharmacological properties are reviewed. The pharmacokinetics (e.g. oral bioavailability, metabolism, plasma levels) and safety of kaempferol are also analyzed. This information may help understand the health benefits of kaempferol-containing plants and may contribute to develop this flavonoid as a possible agent for the prevention and treatment of some diseases.

A review on the dietary flavonoid kaempferol.

El Brazil es considerado un de los principales paises productores de zumos de frutos, ocupando en concreto la tercera posicion respecto a esto. La diversidad de frutos en el mercado es cada vez mayor, introduciendose diariamente nuevos frutos tropicales cuyas propiedades y actividades no estan aun totalmente determinadas. El gobierno brasileno apoya el comercio exterior de frutos, invirtiendo fondos en exposiciones que promueven y situan a los nuevos productos en los paises de la Union Europea, tal como la "Brazilian Fruit Festival" que promociona frutos in natura, pulpas congeladas y zumos procesados. Se publican cada vez en mayor numero nuevas investigaciones que asocian el consumo de frutas con efectos beneficiosos para la salud humana. Este trabajo tiene por objeto la determinacion del indice de fenoles totales (FT), antocianos totales (AT) y la capacidad antioxidante de las pulpas de frutos comerciales congelados, aplicando los metodos espectrofotometrico quimicos mas en boga para la determinacion de la actividad antioxidante (ABTS, DPPH y DMPD). Se ha determinado la capacidad antioxidante de las pulpas de los frutos tropicales de mayor consumo en el mercado del sur de Brazil (mora, uva, acai, guayaba, fresa, acerola, pina, mango, graviola, cupuacu y maracuya) aplicando el metodo ABTS con medidas a dos tiempos (1 y 7 minutos), DPPH (30 y 60 minutos) y DMPD (10 minutos). Los valores TEAC (capacidad antioxidante equivalente al Trolox) obtenidos de las pulpas oscilan entre minimos y maximos de 2,0 y 67,2 µmol/g aplicando el ensayo ABTS, 1,02 y 67,0 µmol/g aplicando DPPH y 4,2 y 46,6 µmol/g aplicando DMPD. La capacidad antioxidante obtenida por los metodos ABTS y DPPH se encuentra correlacionada con el contenido de compuestos fenolicos y antocianos.

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Aplicación de diversos métodos químicos para determinar actividad antioxidante en pulpa de frutos

UV skin exposure induces extensive generation of reactive oxygen species (ROS). These can react with DNA, proteins, fatty acids and saccharides causing oxidative damage. Such injuries result in a number of harmful effects: disturbed cell metabolism, morphological and ultrastructural changes, attack on the regulation pathways and, alterations in the differentiation, proliferation and apoptosis of skin cells. These processes can lead to photoaging and skin cancer development. One approach to protecting human skin against the harmful effects of UV irradiation is to use antioxidants as photoprotectives. In recent years naturally occurring herbal compounds such as phenolic acids, flavonoids, and high molecular weight polyphenols have gained considerable attention as beneficial protective agents. In this review, we strive to summarize the findings of studies performed to date, regarding the photoprotective effects of plant phenolics on the skin damage induced by UV radiation.

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Natural phenolics in the prevention of UV-induced skin damage. A review.

UV radiation-induced skin damages may result in pre-cancerous and cancerous skin lesions, and acceleration of skin aging. It involves an imbalance of the endogenous antioxidant system that leads to the increase of free radical levels and inflammation. Therefore, antioxidant supplementation might inhibit such imbalance. In this regard, quercetin is a promising drug, this plant derived lipophilic flavonoid presents the higher antioxidant activity among flavonoids and multiple antioxidant mechanisms. Thus, the present study investigated the possible beneficial effects of topical formulations containing quercetin to inhibit UVB irradiation-induced oxidative damages. Quercetin was administered on the dorsal skin of hairless mice using two formulations, formulation 1 (non-ionic emulsion with high lipid content) and formulation 2 (anionic emulsion with low lipid content). The UVB irradiation (0.31-3.69 J/cm(2)) induced a dose-dependent increase in the myeloperoxidase (MPO) activity (4-2708%) and depletion of reduced glutathione (GSH) (22-68%) in the skin of hairless mice after 6h. These results demonstrated that the UVB doses are not excessive, and additionally, they are lower than the doses used in other similar studies. Proteinases secretion/activity, detected by the qualitative sodium dodecyl sulphate polyacrylamide gel electrophoresis substrate-embedded enzymography (zymography), was also enhanced in the same manner as MPO activity using the UVB dose of 1.23J /cm(2). Formulations 1 and 2 inhibited the MPO activity increase (62% and 59%, respectively), GSH depletion (119% and 53%, respectively) and proteinases secretion/activity. To our knowledge, this is the first study to demonstrate the effectiveness of topical formulations containing quercetin to inhibit the UVB irradiation-induced skin damages. Thus, these data suggest the possible usefulness of topical formulations containing quercetin to prevent UVB radiation skin damages.

Protective effect of topical formulations containing quercetin against UVB-induced oxidative stress in hairless mice.

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Antioxidant activity and phenolic profile of pistachio (Pistacia vera L., variety Bronte) seeds and skins

The aim of the present study was to evaluate the in vitro antioxidant and in vivo photoprotective activities of a lyophilized extract of Capparis spinosa L. (LECS) obtained by methanolic extraction from the flowering buds of this plant. For the in vitro experiments, LECS was tested employing three different models: (a). bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical (DPPH test); (b). peroxidation, induced by the water-soluble radical initiator 2,2'-azobis(2-amidinopropane) hydrochloride, of mixed dipalmitoylphosphatidylcholine/linoleic acid unilamellar vesicles (LUVs) (LP-LUV test); and (c). UV-induced peroxidation of phosphatidylcholine multilamellar vesicles (UV-IP test). The in vivo antioxidant/radical scavenger activity was assessed by determining the ability of topically applied LECS to reduce UVB-induced skin erythema in healthy human volunteers. From the results obtained in in vitro and in vivo tests, LECS showed a significant antioxidant effect. Furthermore, by chromatographic fractionation and spectroscopic methods, we identified the major constituents of LECS, and particularly some flavonols (kaempferol and quercetin derivatives) and hydroxycinnamic acids (caffeic acid, ferulic acid, p-cumaric acid, and cinnamic acid).

In vitro antioxidant and in vivo photoprotective effects of a lyophilized extract of Capparis spinosa L buds.

Antioxidant and photoprotective activity of a crude extract of Culcitium reflexum H.B.K. leaves and their major flavonoids.

The present study was aimed at evaluating the in vitro antioxidant activity and in vivo photoprotective activity of an extract of wine obtained from Jacquez (Vitis aestivalis-cinerea × V vinifera) grapes (JW-E). The chemical profile of the JW-E was characterised by a significant level of proanthocyanidins, together with lower amounts of anthocyanins and hydroxycinnamic acids. The antioxidant activity of the JW-E was assessed by means of various in vitro tests (bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical; peroxidation, induced by the water-soluble radical initiator 2,2′-azobis(2-amidinopropane) hydrochloride, on mixed dipalmitoylphosphatidylcholine/linoleic acid unilamellar vesicles; UV radiation-induced peroxidation in phosphatidylcholine multilamellar vesicles). In all in vitro tests employed, the JW-E proved to possess strong antioxidant/free radical-scavenging effectiveness. Furthermore, when topically applied, a gel formulation containing the JW-E afforded significant in vivo protection against UVB light-induced skin erythema (monitored by reflectance spectrophotometry) in healthy human volunteers.



© 2002 Society of Chemical Industry

Chemical analysis and photoprotective effect of an extract of wine from Jacquez grapes

Six ketoprofen (CAS 22071-15-4) alkylazacycloalkan-2-one ester derivatives (I-VI) were synthesized and evaluated for their anti-inflammatory, analgesic, and ulcerogenic activities after oral administration. Furthermore these derivatives were assayed to determine in vitro their stability in pH 7.4 phosphate buffer and in simulated gastric fluid (pH 2.0 buffer) and their susceptibility to enzymatic cleavage in rat plasma. All the prodrugs showed a good stability both in pH 7.4 phosphate buffer and in pH 2.0 buffer, and they were readily hydrolyzed by rat plasma. Esters I-VI showed an anti-inflammatory activity, determined as the percent of inhibition of carrageenan-induced edema, similar to that of ketoprofen, although at higher doses. They were significantly less irritating to the gastric mucosa than the parent drug. In the mouse acetic acid induced writhing assay, the prodrugs exhibited, following acute administration, a good analgesic activity.

1-ethyl and 1-propylazacycloalkan-2-one ester prodrugs of ketoprofen. Synthesis, chemical stability, enzymatic hydrolysis, anti-inflammatory activity, and gastrointestinal toxicity.

Dario Ventura

Papers

In vitro antioxidant and in vivo photoprotective effects of a lyophilized extract of Capparis spinosa L buds.

Antioxidant and photoprotective activity of a crude extract of Culcitium reflexum H.B.K. leaves and their major flavonoids.

Chemical analysis and photoprotective effect of an extract of wine from Jacquez grapes

1-ethyl and 1-propylazacycloalkan-2-one ester prodrugs of ketoprofen. Synthesis, chemical stability, enzymatic hydrolysis, anti-inflammatory activity, and gastrointestinal toxicity.

1‐Ethyl and 1‐Propylazacycloalkan‐2‐one Ester Prodrugs of Ketoprofen.