Antonio Rapisarda

Characterization of the polyphenolic fraction of Morus alba leaves extracts by HPLC coupled to a hybrid IT-TOF MS system.

Infusions or dried leaves from Morus alba (L., Moraceae) have long been used in folk medicine for the prevention or treatment of several diseases. Despite the great interest in determining the role of phytonutrients as potential therapeutic agents, and the rising demand of natural sources with nutraceutic benefits, the antioxidant content of many foodstuffs is unknown, making accurate estimation for human dietary consumption and the correlation to human diseases difficult. The high content in polyphenols mainly accounts for in vitro and in vivo antioxidant activity of extracts obtained from this plant, and it is responsible for their preventive and therapeutic roles in a number of human diseases. In this study, we achieved full characterization and quantitation of flavonoids and other phenolic components extracted from lyophilized mulberry leaves, by maceration with ethanol. To tackle such a task, an RPLC-diode array detector-MS system was optimized, employing a partially porous octadecylsilica column as stationary phase. Identification of mulberry leaves constituents was carried out on the basis of the complementary information obtained from their migration times, diode array spectra, MS ions, and MS/MS fragments. The employment of the hybrid (IT-TOF) mass spectrometer further allowed the structural assignment of a series of structural isomers. To the best of our knowledge, 11 out of 22 identified compounds are being reported in mulberry leaves for the first time, and the relative amounts determined, in the two cultivars analyzed.

Betula pendula leaves: Polyphenolic characterization and potential innovative use in skin whitening products

The research of new tyrosinase inhibitors is currently important for the development of skin whitening agents; particularly, birch leaves extracts are included in many skin cosmetic products. In this study, the potential ability of Betula pendula leaves ethanolic extract (BE) was evaluated on mushroom tyrosinase activity. Results showed that BE was capable to inhibit dose-dependently l-DOPA oxidation catalyzed by tyrosinase. The inhibition kinetics, analyzed by Lineweaver-Burk plots, showed a noncompetitive inhibition of BE towards the enzyme, using l-DOPA as substrate. The inhibitory mechanism of BE as studied by spectrophotometric analysis, demonstrated its ability to chelate copper ion in the active site of tyrosinase. In addition, BE exhibited Fe(2+)-chelating ability (IC(50)=614.12±2.14 μg/mL), reducing power and radical-scavenging properties (IC(50)=137.22±1.98 μg/mL). These results suggest the usefulness of birch leaves extracts in cosmetic and pharmaceutical industries for their skin-whitening and antioxidant effects. Determination of the polyphenolic compounds in BE extracts was afterward achieved by means of high-performance liquid chromatography (HPLC) with photodiode array (PDA) and mass spectrometry (MS) detection. A total of 25 compounds were positively identified, through the complementary analytical information, and are reported in such a matrix for the first time. Knowledge on the qualitative composition and contents of these natural sources in fact represents mandatory information, for rational consumption and correlation of the beneficial effects to the specific amounts.

Effect of 2,6-Diisopropylphenol on the delayed hippocampal cell loss following transient forebrain ischemia in the gerbil

We examined the protective activity of 2,6-diisopropylphenol on mortality and delayed hippocampal cell death induced by transient cerebral ischemia in the gerbil. Forebrain ischemia was produced by bilaterally occluding the common carotid arteries for 10 minutes; then the blood supply to the brain was restored. The number of survivors was counted for 8 days, and the histopathological damage in the CA1 region of the hippocampus was scored according to the semiquantitative scale of Rudolphi and Colleagues. When intraperitoneally injected immediately after the ischemic attack, 2,6-diisopropylphenol (25, 50, 100 mg kg-1) produced no significant reduction in the rate of mortality in comparison with its vehicle. However, the survivors that had received the compound at the dose of 50 and 100 mg kg-1 elicited a significant increase in the number of viable pyramidal cells in the CA1 hippocampal region. Moreover, we obtained similar results by injecting the compound 30 minutes after the release of the carotid artery occlusion. These results suggest that 2,6-diisopropylphenol, although it does not show any capability of improving the rate of survival, it elicits protective properties against the transient forebrain ischemia-induced delayed hippocampal neuronal death.

Nepeta sibthorpii Bentham (Lamiaceae): micromorphological analysis of leaves and flowers.

Nepeta sibthorpii Bentham (Lamiaceae) is an herbaceous aromatic plant, growing in dry, usually rocky areas of Southern Greece. In this paper, we report the study of micromorphological features of the flowers and leaves of Nepeta sibthorpii Bentham. The analysis by means of scanning electron microscopy has permitted to characterize both the covering trichomatous garment, abundantly present on the calyx and on the leaves, and the glandular hairs, distributed on the adaxial leaf surface and on the outer surfaces of calyx and corolla, showing also the peculiar features of the epidermal cells, all useful diagnostic elements for the identification of this medicinal plant.

Micromorphological study on leaves of someCordia (Boraginaceae) species used in traditional medicine

The genus Cordia (Boraginaceae) is made up of a great many species widely distributed in tropical and subtropical regions of the world. The leaves ofCordia myxa, as also those of many other species of the same genus, have been utilized in the traditional medicine of many countries for the treatment of a variety of diseases. Observed by light microscope and by scanning electron microscope the histological characteristics of the leaf ofCordia francisci, C. martinicensis, C. serratifolia andC. ulmifolia, species grown in Sicily, compared also with those of the leaves ofC. myxa originating from Africa, are described in detail. It has been possible to reveal some morphological elements that allow leaf identification and the differentiation of the drugs examined.RésuméLe genreCordia (Boraginaceae) est composé d’un trés grand nombre d’especes largement distribuisees dans les régions tropicales et subtropicales du monde. Les feuilles deCordia myxa, tout comme celles de nombreuses autres especes du méme genre, ont été utilisées dans la médicine traditionnelle de maints pays dans le traitement de diverses maladies. On a décrit en détail les caractéristiques histologiques de la feuille de Cordia francisci.,C. martinicensis, C. serratifolia etC. ulmifolia, espéces qui poussent en Sicile et qui ont été observées au microscope optique et au microscope electronique á balayage. On les a également comparées a celles des feuilles deC. myxa L., provenant de l’Afrique. Il a été possible de découvrir quelques éléments morphologiques qui ont permis l’identification de la feuille et la différentiation des drogues examinées.

Antioxidant, α-amylase inhibitory and brine-shrimp toxicity studies on Centaurea centaurium L. methanolic root extract

Free radical scavenging activity of the methanolic extract of the roots of Centaurea centaurium L. (Asteraceae) and its phenolic, non-polar and water fractions was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The phenolic fraction showed high radical-scavenging activity with DPPH (IC50 of 57 µg mL−1) and potent antioxidant properties both on lipid peroxidation and β-carotene bleaching (IC50 of 195 and 5 µg mL−1, respectively). The n-hexane fraction of the extract showed the highest inhibitory activity against α-amylase with an IC50 of 158 µg mL−1. In this fraction, the most abundant constituents were the fatty acids: 11,14-eicosadienoic acid methyl ester, 9-octadecenoic acid methyl ester and 9-octadecenoic acid. Various terpenes, e.g. cypirene, α-zingiberene, β-farnesene, β-santalene, β-bisabolene, β-himachalene and azulene were also present. The LC50 against the brine shrimp nauplii for the methanolic extract was found to be 44.05 µg mL−1, whilst LC50 values for the polyphenolic, lipophilic and water fractions were found to be 157.44, 25.98 and 152.81 µg mL−1, respectively.

Trichilia roka Chiov. (Meliaceae): pharmacognostic researches.

The dried aqueous extract of Trichilia roka Chiov. (Meliaceae) root was evaluated for its potential antipyretic activity on yeast-induced hyperthermia in rats. The drug showed a significant reduction of body temperature when administered orally at the doses of 0.25, 0.5 and 1.0 g/kg. The antipyretic activity of T. roka was compared to indomethacin treatment (50 mg/kg), used as a reference drug. The results of this study confirm the validity of traditional usage of T. roka as an antipyretic agent. Moreover, micromorphological investigations were carried out by scanning electron microscopy obtaining useful phytognostic elements for the correct identification of the drugs both in scraped and powdered forms because this is of great interest for quality control in basic research and drug production, especially for imported items and for raw material sold by traditional herborists.

Searching for indole derivatives as potential mushroom tyrosinase inhibitors

Abstract Tyrosinase is a copper-containing enzyme widely distributed in nature, involved in the biosynthesis of melanin whose role is to protect the skin from ultraviolet damage. A great interest has been shown on the melanin involvement in malignant melanoma and other carcinogenetic processes. These phenomena have encouraged the research of tyrosinase inhibitors useful in therapeutic field as well as in foods and cosmetics to prevent browning. The idea was to screen our “in house” database to select suitable lead compounds for the discovery of potential drug-inhibiting enzyme. The obtained biological results demonstrated that compounds containing 4-fluorobenzyl moiety at N − 1 position of indole system showed the best activity. In addition, the role of the portion linked to the carbonyl group at C − 3 was discussed. A Lineweaver–Burk kinetic analysis of the most active indoles, CHI 1043 and derivative 4, showed a mixed-type inhibition in the presence of l-3,4-dihydroxyphenylalanine (l-DOPA) as substrate.

Anti-angiogenic activity of Entada africana root

Entada africana roots are used in African traditional medicine for various diseases including inflammation. This application may be mediated through anti-angiogenic effects. Thus, in this study the anti-angiogenic activity of E. africana root extracts (n-hexane, chloroform, chloroform/methanol and methanol) was preliminarily evaluated by the quantitative determination of endogenous alkaline phosphatase in zebrafish embryos. A bioactivity-guided fractionation of chloroform/methanol extract yielded apigenin and robinetin as the main constituents from the most active fractions. In addition, a marked reduction on capillary formation was evidenced in chick chorioallantoic membrane after treatment with the active fractions or isolated compounds. Results obtained in this study suggest that the anti-angiogenic effects of E. africana root may account for its use in inflammatory diseases and other related pathological conditions.

Effects of cadmium on growth and pharmacologically active constituents of the medicinal plant Coriandrum sativum L.

The effects of high levels of cadmium in soil and in the atmosphere on the plants of Coriandrum sativum L. (Umbellifereae) were investigated. Plants grown in contaminated soil (0, 10, 100 ppm of cadmium) showed a significant reduction in the length of the stems and roots and the number of the umbels, a yellowing and ultrastructural alterations of the leaves and a significant decrease in the essential oil composition. Similar effects were observed in the plants exposed to a simulated atmospheric pollution (plants were sprayed with CdCl2 solutions containing Cd 0, 10, 100 mg/L). The effects are related to a degree of environmental contamination.