B. Tosi

Antimicrobial Activity of Some Commercial Extracts of Propolis Prepared with Different Solvents

Some commercial extracts of propolis obtained with different solvents were tested to evaluate their antibacterial and antifungal activity. All propolis preparations exhibited antimicrobial activity, particularly against Gram‐positive bacteria, yeasts and dermatophytes with zones of inhibition ranging from 3 to 30 mm. Against yeasts and dermatophytes, oil, ethanol and propylene glycol solutions showed an inhibition for more 2 weeks, while the glycerine solution maintained inhibition only for some days. The results indicate that the solvent employed for the extraction may enhance the potency of the antimicrobial activity of propolis. Consistency in the properties and characteristics of propolis were related to the formulation of extraction procedures.

Chicory extracts from Cichorium intybus L. as potential antifungals

In this work extracts from roots of the common vegetable Cichorium intybus L., highly appreciated for its bitter taste, were studied to investigate their possible biological activity on fungi from a variety of ecological environments: some are parasites on plants (phytopathogens) or of animals and humans (zoophilic and anthropophilic dermatophytes), others live on the soil and only seldom parasitize animals (geophilic dermatophytes). The extracts were ineffective on geophilic species and on tested phytopathogens, with the exception of Pythium ultimum, whereas they inhibited the growth of zoophilic and anthropophilic dermatophytes, in particular Trichophyton tonsurans var. sulfureum, whose treatment caused morphological anomalies, here observed by scanning electron microscopy. This behaviour is discussed on the basis of the presence in the chicory extract of the two main sesquiterpene lactones, 8-deoxylactucin and 11β,13-dihydrolactucin.

Variation in the content of the main guaianolides and sugars in Cichorium intybus var. “Rosso di Chioggia” selections during cultivation

Abstract Cichorium intybus var. “Rosso di Chioggia” is a chicory variety cultivated predominantly in Northeastern Italy and highly appreciated for its bitter taste. The commercial portion of the plant, used as food, comprises the innermost leaves (head) of plants harvested during the first year of growth; the outermost leaves and the roots are considered wastes. Three selections belonging to this variety have been analyzed for guaianolide and sugar contents and compared with the commercial product (head), roots and outermost leaves. The qualitative and quantitative evaluations of both classes of compounds were achieved by densitometric HPTLC. The analytical data showed a high variability during the stages of growth, both among the parts of the plant and among the three selections of chicory considered. With particular reference to the heads, a sensory bitterness evaluation method was set up in order to find a correlation between the analytical data and the bitter taste.

Mannan changes induced by 3-methyl-5-aminoisoxazole-4-thiocyanate, a new azole derivative, on Epidermophyton floccosum

The antifungal activity of 3-methyl-5-aminoisoxazole-4-thiocyanate, a new azole derivative, was studied on the dermatophyte Epidermophyton floccosum. The compound strongly inhibited the in vitro growth of two different strains of the fungus and even induced profound morphogenetic anomalies. Optical and electron microscopy showed that such treatment targets the endomembrane system, particularly the plasmalemma, causing abnormal extrusion of the wall mannans. This results in improper arrangement of the different parietal materials; the walls are thus weak and subject to subapical rupture which terminates cell growth and elongation of the hypha. The morphological results and the preliminary biochemical data on fungal sterols suggest that this compound employs an action mechanism similar to that of other azoles used in therapy.

Antifungal Activity of Tagetes patula Extracts

In the present paper the methanol extracts obtained from 10 cultivars of Tagetes patula were assayed on two phytopathogenic fungi: Botrytis cinerea and Fusarium moniliforme. B. cinerea showed a high dose-dependent inhibition, with a marked difference between light and dark treatment. F. moniliforme seems to be a more resistant test that does not appear to be affected by the different treatment conditions (light-dark) even at the highest dose. However, it can be asserted that Tagetes patula is a possible source of antifungal substances and that thiophene activity is, in general, strongly increased by UV-A irradiation. During the experiment the method of chromatographic plates was used to evaluate plant extracts bioactivity. The obtained data indicate that it is a rapid method than can be used as an alternative to Petri dish tests.

Fluorogenic detection of primary amines in plant histochemistry with fluorescamine: A comparative study on the effects of coagulant and non-coagulant fixatives

SummaryThe new highly sensitive method of fluorescamine reaction for the topochemical detection of primary amino groups was studied as a substitude of ninhydrin-Schiffs reaction for the localisation of total proteins in plant tissues. The influence of various coagulant and non-coagulatn fixatives on the induction of fluorescamine fluorescence was examined: ethanol, formaldehyde gas and solution, glutaraldehyde, acrolein, osmium tetroxide, Bouin, Rossman, Clarke and Zenkers fluids and FMA were employed. It was found that the use of the fluorogenic method is conditioned by the fixative ability to keep the amino groups disposable and by its capability to reduce the natural autofluorescence of plant material. A detailed account of the fixation methodology demonstrated that non-coagulant acrolein and coagulant mercuric chloride are the most promising fixatives for the use of the fluorescamine reaction in plant histochemistry.

Quaternary alkaloids in rhizomes of Ranunculus serbicus

The isolation, identification and quantification of four alkaloids from the quaternary alkaloid fraction of rhizome extracts of Ranunculus serbicus is described. The alkaloids isolated were the protoberberine-type palmatine, berberine and columbamine, and the benzylisoquinoline-type magnoflorine. This is the first reported isolation of quaternary alkaloids in the genus Ranunculus.

Fluorescamine, a fluorescence probe for amino groups in histochemical studies of plant cells and the effect of mercury fixation.

SynopsisWhen fixed in mercuric chloride solutions and stained with Fluorescamine, histological plant specimens emit a strong fluorescence. The fluorophore distribution is topologically identical to the staining pattern revealed by visible light methods for nucleoproteins, but the fluorescence mode of viewing preparations gave greater sensitivity and contrast than transmitted light absorption methods. The parameters that influence the formation of the fluorescent image in plant cells are discussed. The results obtained indicate that the mercury-Fluorescamine reaction is an ideal histochemical procedure for collecting qualitative and analytical information on plant nuclei and on the changes of nucleolar architecture that occur during the cellular developmental cycle.

A method for localizing embryonal laticifers by combined conventional and fluorescence microscopy

SummaryThe authors describe a simple method based on malachite green and acid fuchsin for the detection of laticifers during the embryogenesis of someEuphorbiaceae plants by conventional and fluorescence microscopy. The strong sensitivity and specificity of the method make it suitable for the ontogenetic studies of laticifers. The results obtained are discussed in the context of the reactive mechanism of the staining and of the chemical composition of the embryonal laticifers.

Presence of Scopoletin in Malva sylvestris

Malva sylvestris L. (Malvaceae) contains scopoletin in a range of 10 ± 1.3 to 30 ± 0.9 μg/g dry weight. The content was found to be higher in the aqueous extract compared with the MeOH extract of the same sample.