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Biomedical subjects

Ivano Morelli

Publications and source records attributed to Ivano Morelli.

49 records · Page 3Linked to original sources
PubMed2003

Natural modulators of large-conductance calcium-activated potassium channels.

Large-conductance calcium-activated potassium channels, also known as BK or Maxi-K channels, occur in many types of cell, including neurons and myocytes, where they play an essential role in the regulation of cell excitability and function. These properties open a possible role for BK-activators (also called BK-openers) and/or BK-blockers as effective therapeutic agents for different neurological, urological, respiratory and cardiovascular diseases. The synthetic benzimidazolone derivatives NS004 and NS1619 are the pioneer BK-activators and have represented the reference models which led to the design of several novel and heterogeneous synthetic BK-openers, while very few synthetic BK-blockers have been reported. Even today, the research towards identifying new BK-modulating agents is proceeding with great impetus and is giving an ever-increasing number of new molecules. Among these, also a handsome number of natural BK-modulator compounds, belonging to different structural classes, has appeared in the literature. The goal of this paper is to provide a possible simple classification of the broad structural heterogeneity of the natural BK-activating agents (terpenes, phenols, flavonoids) and blockers (alkaloids and peptides), and a concise overview of their chemical and pharmacological properties as well as potential therapeutic applications.

Benzimidazoles↗
PubMed2003

Variability of the essential oil of Viola etrusca.

Essential oils obtained from different populations of Viola etrusca from Italy have been analysed to verify the phenotypic discontinuity observed in a previous study. All of the essential oils contained methyl salicylate as a main constituent. However, multivariate analysis showed differences among some populations, in particular between northern and southern ones. Results suggest that this species could be undergoing a slow schizogenetic differentiation process due to its genetic isolation.

Cluster Analysis↗
PubMed2002

Differences in the fragrances of pollen and different floral parts of male and female flowers of Laurus nobilis.

The headspace analyses of pollen, whole living female and male flowers, and staminoids have been performed on Laurus nobilis L. (Lauraceae) from Italy to determine whether there are differences in the volatiles emitted in order to give a contribution to the roles of the different flower parts in the pollination ecology of dioecious plants. Also, the essential oils obtained from male and female plants have been studied to evaluate a possible correlation between the spontaneously emitted volatiles and the constituents stored in the glandular tissues. Furthermore, the headspace sampling technique has been improved, with respect to previously employed methods, by means of solid-phase microextraction (SPME).

Chromatography, Gas↗
PubMed2002

Main agronomic-productive characteristics of two ecotypes of Rosmarinus officinalis L. and chemical composition of their essential oils.

The productive potential of two different ecotypes of Rosmarinus officinalis (Cevoli and Lunigiana) cultivated in the littoral area near Pisa (northern Tuscany, Italy) and the differences in the yield and composition of the essential oils of leaves, flowers, and stems obtained from different positions of the plants were used to characterize the two ecotypes. The Cevoli ecotype plant produced the highest yield of dry matter (221 g plant-1) in comparison to the Lunigiana ecotype (72 g plant-1). There were significant differences in dry matter production of different organs of both ecotypes. The essential oil contents of Cevoli and Lunigiana ecotypes were similar. In contrast, the oil contents of the different plant parts showed marked differences. The apical part of the plant and the leaves gave the highest essential oil yields. The major difference between the oils of the two ecotypes consisted in the 1,8-cineole contents (6.6 and 37.9% in Cevoli and Lunigiana, respectively). The Cevoli ecotype was determined to be the most suitable for essential oil extraction because it was characterized by a preponderance of flowers and leaves in the apical portion. The Cevoli ecotype could be classifited as an alpha-pinene chemotype, whereas Lunigiana is a 1,8-cineole chemotype.

Agriculture↗
PubMed2002

Three anthrones from Rubus ulmifolius.

From the aerial parts of Rubus ulmifolius Schott three new anthrones, rubanthrone A, B and C, have been isolated. Their structures were established by spectral procedures including 1D and 2D NMR techniques and chemical derivatization. Rubanthrone A showed antimicrobial activity against Staphylococcus aureus at 4.5 mg/ml.

Anthracenes↗
PubMed2002

Flavonoid glycosides from Centaurea pseudoscabiosa subsp. pseudoscabiosa from Turkey.

Three flavonoid glycosides were isolated and characterized, together with a further 13 substances belonging to various classes of compounds, in particular two phenolic acids, a coumarin, a sugar and nine flavonoids from the flowered aerial parts of Centaurea pseudoscabiosa subsp. pseudoscabiosa Boiss. et Buhse (Asteraceae). Some considerations about their evolutionary meaning are provided.

Biological Evolution↗
PubMed2002

Vasodilator activity of crude methanolic extract of Gentiana kokiana Perr. et Song. (Gentianaceae).

Gentiana kokiana Perr. et Song. is a plant employed in the traditional medicine of Tuscany (Italy) as antihypertensive remedy. The aim of this work was to evaluate a possible vascular action of the plant and to investigate its mechanism of action. The methanolic extract of roots showed an endothelium-independent vasodilator activity in aortic rings pre-contracted by norepinephrine (NE) 3 microM and a marked depression of the contracturant responses induced by KCl and caffeine, and by NE, both in Tyrode solution and Ca2+-free Tyrode solution. An action on the Ca2+-extracellular influx was discarded, while release or uptake mechanisms of the sarcoplasmic reticulum were hypothesized. However, the incapacity of cyclopiazonic acid (20 microM), a blocker of Ca2+/ATPase of the sarcoplasmic reticulum, to reduce the vasodilator action of the extract allowed to exclude the involvement of such a mechanism. A possible involvement of the ryanodine-sensitive Ca2+ channels is suggested.

Animals↗
PubMed2002

Antioxidant activity of flavonoids from Licania licaniaeflora.

In our screening program for antioxidants with DPPH radical scavenging activity we tested several flavonoids isolated from the leaves of Licania licaniaeflora (Chrysobalanaceae family) and identified by spectroscopic evidence, particularly with 1H and 13C NMR. All the isolated compounds exhibited DPPH radical scavenging activity: quercetin derivatives showed the strongest action, while the flavanone 8-hydroxy-naringenin and kaempferol 3-O-alpha-rhamnoside had the lowest.

Antioxidants↗
PubMed2002

Cardiovascular effects of Urtica dioica L. (Urticaceae) roots extracts: in vitro and in vivo pharmacological studies.

Urtica dioica (Urticaceae) is a plant principally used in the traditional medicine of oriental Marocco as antihypertensive remedy (J. Ethnopharmacol., 58 (1997), 45). The aim of this work was to evaluate a possible direct cardiovascular action of the plant and to investigate its mechanism of action. In aortic preparations with intact and functional endothelial layer, pre-contracted with KCl 20 mM or norepinephrine 3 microM, the crude aqueous and methanolic extracts of the plant roots, as well as purified fractions elicited a vasodilator action. Nevertheless, the vasodilator activity was not present in aortic rings without endothelial layer. In aortic rings with intact endothelial layer, the vasorelaxing effect was abolished by L-NAME, a NO-biosynthesis inhibitor, and ODQ, a guanylate cyclase inhibitor. Furthermore, potassium channel blockers (TEA, 4-aminopyridine, quinine, but not glybenclamide) antagonized the vasodilator action of the purified fraction F1W of U. dioica. The same fraction produced a marked decrease of inotropic activity, in spontaneously beating atria of guinea-pig, and a marked, but transient, hypotensive activity on the blood pressure of anaesthetized rats. It is concluded that U. dioica can produce hypotensive responses, through a vasorelaxing effect mediated by the release of endothelial nitric oxide and the opening of potassium channels, and through a negative inotropic action.

Animals↗
PubMed2002

Antioxidant and free-radical scavenging activity of constituents of the leaves of Tachigalia paniculata.

Two new myricetin glycosides, myricetin 7-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (1) and myricetin 7-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (2), together with the known compounds quercetin 3-O-beta-D-glucopyranoside (3), quercetin 3-O-alpha-L-rhamnopyranoside (4), quercetin 3-O-beta-D-galactopyranoside (5), methyl gallate (6), isovanillin (7), 4-hydroxymethylbenzoate (8), 3,4-dihydroxymethylbenzoate (9), and caffeoyl aldehyde (10) were isolated from the leaves of Tachigalia paniculata. The structures of these compounds were determined by spectroscopic methods. Their antioxidant activity was determined by measuring free-radical scavenging effects using three different assays, namely, the Trolox Equivalent Antioxidant Capacity (TEAC) assay, the coupled oxidation of beta-carotene and linoleic acid (autoxidation assay), and the inhibition of xanthine oxidase activity. Compounds 1, 2, and 6 showed activity in the TEAC test, compounds 5-7 and 10 were moderately active in the autoxidation assay, while compounds 1 and 2 were the most potent of the isolates in the xanthine oxidase test.

Algorithms↗
PubMed2002

Structure and absolute configuration of new diterpenes from Lavandula multifida.

Four new diterpenes (1-4) have been isolated from the aerial parts of Lavandula multifida, together with the known compound glutinosin (5). The structures of these compounds were identified on the basis of extensive NMR studies as 15,16-dihydroxy-7,11-dioxopimar-8(9)-ene (1), 15S,16-dihyroxy-7-oxopimar-8(9)-ene (2), 15,16,17-trihydroxy-7-oxopimar-8(9)-ene (3), and 15,16,17-trihydroxypimar-8(9)-ene (4). The absolute configuration of the 15,16-diol moiety in 1-5 was determined observing the circular dichroism induced after addition of dimolybdenum tetracetate in DMSO solution.

Circular Dichroism↗
PubMedDate not supplied

Archaeobotanic evidence of the preincaic Chiribaya culture. Determination of capsaicinoids in archaeological samples of Capsicum frutescens and votive foods.

The lack of Capsicum species or paprika (a basic ingredient of Peruvian foodstuff) in preincaic archaeological samples and votive foods, as evidenced by archaeobotanic studies, has stimulated the chemical analyses of these samples by HPLC methods. The results confirmed the absence of capsaicinoids in these samples whereas they were detected in more ancient fossil fruit.

Archaeology↗