No abstract

Enormous marine biodiversity offers an endless reservoir of chemicals for many applications. In this scenario, the extraction of seaweeds represents an interesting source of compounds displaying antimicrobial activity. In particular, among the different red algae, Gracilaria gracilis plays an important role due to the presence of important bioactives in its composition. In spite of these features, an efficient culture system is still absent. In the present study, a novel algal culture method was developed and compared to another more common cultural practice, widely reported in literature. A higher efficiency of the new method, both for daily growth rate and biomass, was assessed. Furthermore, the growth inhibitory activity of five extracts, obtained using ethanol, methanol, acetone, chloroform or diethyl ether as a solvent, from the cultured G. gracilis was tested against Gram-positive and Gram-negative pathogens. Algal extracts exhibited a considerable inhibitory activity against B. subtilis strains, while a slight inhibition was observed against V. fischeri. The different extracts showed significant differences in bacterial growth inhibition, with the highest activity that was recorded for the ethanol extract, followed by that of methanol. Based on the chemical characterization, these findings could be related to the antimicrobial activity played by the combination of total carbohydrates and polyphenols, which were determined at high levels in ethanol and methanol extracts, as well as by the highest number and levels of single polyphenols. Conversely, the lower growth inhibitory activities found in chloroform and diethyl ether extracts could be related to the isolation of minor lipid classes (e.g., neutral and medium polar lipids) composed by fatty acids, such as stearic, oleic and arachidonic acids, typically characterized by antimicrobial activity. In consideration of the results obtained, the present study has a double implication, involving both the field of cultural practices and the exploitation of natural sources for the isolation of antimicrobial agents useful both in pharmaceutical and food applications.

Recently the miniaturization of liquid chromatography (LC) systems and progresses in mass spectrometry instrumentation have enabled direct introduction of the effluent coming from a nanoLC column into the high-vacuum region of an electron ionization source. In the present research, a nanoLC system was directly coupled to an electron ionization mass spectrometer (EI-MS) without any interface or modification of the ion source. The advantage with respect to atmospheric pressure ionization techniques, normally coupled with LC, is major identification power because of a more extensive and reproducible fragmentation pattern, without any matrix effect or mobile-phase interference. In particular, a nanoLC/EI-MS method was developed for elucidation of the free fatty acid profile in mussel samples, avoiding a previous derivatization step, required when gas chromatographic analysis is involved. A total of 20 fatty acids were reliably identified through the comparison with commercial libraries. A quantitative determination was also carried out by using the response factors approach along with the internal standard method, allowing for quantification of 14 fatty acids. Among them, palmitic acid resulted the most abundant, followed by ω6 arachidonic acid. The quantitative data were compared with those obtained by a well-established technique, such as gas chromatography with flame ionization detection (GC-FID). Both nanoLC/EI-MS and GC-FID methods were validated and similar results were obtained in terms of limit of detection and quantification, resulting in the picomole range, and sensitivity as well was not significantly different, as demonstrated by comparing the slope values of the calibration curves (p < 0.05, from a t-test).

Although the antitumour activity of Vitex agnus castus fruits has been already addressed, no work has yet assessed their anti-angiogenic potential. To this purpose, several extractive fractions of such fruits were tested on zebrafish embrios by EAP assay, so that only the bioactive fractions could be subsequently tested on the chick chorioallantoic membrane by CAM assay. Bioactive fractions were also phytochemically screened to identify those bioactive compounds responsible for anti-angiogenic activity. A marked inhibition of vessel formation was detected only in zebrafish embryos treated with chloroform or ethyl acetate fractions. Considering CAM assay, chloroform fraction induced a strong reduction of microvasculature and haemoglobin content; while lower anti-angiogenic effects of the ethyl acetate fraction were determined. Phytochemical analyses confirmed the presence of several bioactive anti-angiogenic compounds. Overall, obtained preliminary results highlighted a potential anti-angiogenic activity of V. agnus castus fruits.

Different multivariate techniques were tested in an attempt to build up a statistical model for predicting the origin of prickly pears (Opuntia ficus-indica L., cv. Muscaredda) from several localities within the Sicilian region. Specifically, two areas known for producing fruits marked respectively by TAP (traditional agri-food product) and PDO (protected designation of origin) brands, and three sites producing non-branded fruits, were considered. A validated inductively coupled plasma mass spectrometry (ICP-MS) method allowed to obtain elemental fingerprints of prickly pears, which were subsequently elaborated by unsupervised tools, such as hierarchical clustering analysis (HCA) and principal component analysis (PCA), and supervised techniques, such as stepwise-canonical discriminant analysis (CDA) and partial least squares-discriminant analysis (PLS-DA). With the exception of HCA, which was not enough powerful to correctly cluster all selected samples, PCA successfully investigated the effect of subregional provenance on prickly pears, thus, differentiating labeled products from the non-labeled counterpart. Also, stepwise CDA and PLS-DA allowed to build up reliable models able to correctly classify 100% of fruits on the basis of the production areas, by exploiting a restricted pool of metals. Both statistical models, including unsupervised (PCA) and supervised techniques (stepwise CDA or PLS-DA), may guarantee the provenance of prickly pears protected by quality labels and safeguard producers and consumers.Practical Application: Based on elemental analysis and chemometrics, the reliable traceability models herein proposed, could be applied to commercial Sicilian prickly pears protected by TAP and PDO logos to guarantee their provenance and, at the same time, to safeguard producers and consumers.