1,598 research outputs found
Relationship between Volatile Composition and Bioactive Potential of Vegetables and Fruits of Regular Consumption—An Integrative Approach
In recent years, there has been a growing interest in studying and exploring the potential
health benefits of foods, mainly from vegetables and fruits from regular intake. The presence of
secondary metabolites, namely polyphenols, carotenoids and terpenes, in certain food matrices
seems to contribute to their functional properties, expressed through an increased prevention in the
development of certain chronic diseases, namely coronary heart diseases, neurodegenerative diseases,
cancer and diabetes. However, some foods’ volatile secondary metabolites also present important
bioactive properties, although this is a poorly scientifically explored field. In this context, and in
order to explore the potential bioactivity of volatile metabolites in different vegetables and fruits from
regular consumption, the volatile composition was established using a green extraction technique,
solid phase microextraction in headspace mode (HS-SPME), combined with gas chromatography
tandem mass spectrometry (GC-MS). A total of 320 volatile metabolites, comprising 51 terpenic
compounds, 45 organosulfur compounds, 31 aldehydes, 37 esters, 29 ketones, 28 alcohols, 23 furanic
compounds, 22 hydrocarbons, 19 benzene compounds, 13 nitrogenous compounds, 9 carboxylic
acids, 7 ethers, 4 halogenated compounds and 3 naphthalene derivatives, were positively identified.
Each investigated fruit and vegetable showed a specific volatile metabolomic profile. The obtained
results revealed that terpenic compounds, to which are associated antimicrobial, antioxidant, and
anticancer activities, are the most predominant chemical family in beetroot (61%), orange carrot
(58%) and white carrot (61%), while organosulfur compounds (antiviral activity) are dominant
in onion, garlic and watercress. Broccoli and spinach are essentially constituted by alcohols and
aldehydes (enzyme-inhibition and antimicrobial properties), while fruits from the Solanaceae family
are characterized by esters in tamarillo and aldehydes in tomato.info:eu-repo/semantics/publishedVersio
Chemical fingerprint of free polyphenols and antioxidant activity in dietary fruits and vegetables using a non-targeted approach based on QuEChERS ultrasound-assisted extraction combined with UHPLC-PDA
Fruits and vegetables are considered a good source of antioxidants, which are beneficial in
protecting the human body against damage induced by free radicals and other reactive oxygen (ROS)
and nitrogen (RNS) species. In this work, we aimed to evaluate the integral antioxidant activity (AOA)
and determine individual polyphenols in fruits and vegetables of frequent consumption. For this
purpose, an innovative and high throughput analytical approach based on original QuEChERS assisted
by ultrasound extraction (USAE), instead of the manual agitation used in the classical procedure,
was optimized and implemented for the isolation of polyphenols. The total phenolic content (TPC),
flavonoids, anthocyanins, and betalains were evaluated using different spectrophotometric assays.
In addition, free radical scavenging by methods 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonate)
(ABTS) and 2,20
-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP)
were used to estimate the AOA of the investigated fruit and vegetable extracts. Red onion,
tamarillo, and beetroot were the samples with the highest AOA. The quantification and identification
of free low molecular weight polyphenols from QuEChERS-USAE extracts was carried out by
ultra-high-pressure liquid chromatography equipped with a photodiode array detection system
(UHPLC-PDA). Catechin was the most abundant polyphenol, followed by gentisic and ferulic acids,
mainly in the watercress sample. In relation to flavonols, quercetin and kaempferol were found mostly
in onion samples, and in small quantities in tomato and watercress. The improved analytical approach,
QuEChERS-USAE/UHPLC-PDA, offers an attractive alternative for the analysis of polyphenols from
fruit and vegetable samples, providing several advantages over traditional extraction techniques, in
terms of reproducibility, simplicity, low cost, analysis speed, and analytical performance.info:eu-repo/semantics/publishedVersio
The synthetic cannabinoids phenomenon: from structure to toxicological properties. A review
The word “cannabinoid” refers to every chemical substance, regardless of structure or origin, that joins
the cannabinoid receptors of the body and brain and that have similar effects to those produced
by the Cannabis plant and based on their source of production, cannabinoids can be classified into
endocannabinoids, phytocannabinoids and synthetic cannabinoids. Synthetic cannabinoids represent
the largest class of drugs detected through the EU Early Warning System with a total of 190 substances
notified from 2008 to 2018 and about 280 have been reported worldwide to the United Nations Office
on Drugs and Crime. Sprayed on natural herb mixtures with the aim to mimic the euphoria effect of
cannabis and sold as “herbal smoking blends” or “herbal incense” under brand names like “Spice” or
“K2”, synthetic cannabinoids are available from websites for the combination with herbal materials or
more recently, for the use in e-cigarettes. Currently labeled as “not for human consumption” to circum vent legislation, their legal status varies by country with many government institutions currently push ing for their control. However, due to the emergence of new substances, it requires a constant update
of the list of controlled drugs. Little is known about how these substances work and their toxic effects
in humans and the same product could vary not only in the amount and in the type of substance
added. In the last years, synthetic cannabinoids have been associated with deaths and acute intoxica tions in Europe and, despite a range of new measures introduced in this area, continue to represent a
challenge to current drug policy models. These synthetic substances are much more potent than nat ural cannabis, as well as displayed greater efficacy, acting as full agonists at the cannabinoid receptors.
It is possible that, along with being highly potent, some may also have long half-lives, potentially lead ing to a prolonged psychoactive effect. The present work provides a review on existing literature about
the development of synthetic cannabinoids as substances of abuse, current patterns of abuse and their
legal status, chemical classification, and some pharmacological and toxicological properties.info:eu-repo/semantics/publishedVersio
Application of 15N natural abundance technique for evaluating biological nitrogen fixation in oil palm ecotypes at nursery stage in pot experiments and at mature plantation sites
Diastereo-selectivity in diels–alder cycloadditions of erythrose benzylidene-acetal 1,3-Butadienes with maleimides
Maleimides were combined with D-erythrose benzylidene-acetal 1,3-butadienes 1 and 2 to study the facial selectivity of the Diels-Alder cycloadditions. The selectivity was found to be from moderate to good. The reaction diastereotopicity can be reversed with the temperature. Simultaneous coordination of diene 1, having a free hydroxyl group, and maleimide 3 to a chiral bimetallic Lewis acid catalyst (LACASA-DA reaction) occurs with complete diastereo-control to give a single adduct, using an extra chiral inductor either R- or S-BINOL.Thanks are due to FCT for project funding PTDC/QUI/67407/2006 and FCT and FEDER for funding the NMR spectrometer Bruker Avance III 400 as part of the National NMR Network. V. C. M. D. also thanks for PhD grant (SFRH/BD/61290/2009)
Asymmetric diels-alder reaction of tert-butyl 2H-azirine-3-carboxylate by a self-assembled complex of binol, mg and zn
The synthesis of an homochiral aziridine as a useful synton to iminosugars and amino acid compounds
Fundação para a Ciência e a Tecnologia (FCT) - PTDC/QUI/67407/200
Synthesis of 1-azafagomine analog and 1-N-phenyl carboxamide 1-azafagomine containing erythrose units
Bioaccessibility of lipophilic and hydrophilic marine biotoxins in seafood: An in vitro digestion approach
This study aimed to assess the bioaccessibility of different marine biotoxins in naturally contaminated shellfish and fish gonads using an in vitro digestion methodology. In general, hydrophilic toxins (domoic acid, paralytic shellfish poisoning toxins and tetrodotoxins) showed higher bioaccessibility than lipophilic ones (okadaic acid and azaspiracids). The bioaccessibility of toxins from the okadaic acid group ranged from 69% (raw European razor clams) to 74% (raw donax clams). Regarding azaspiracids, 47% of the initial content was bioaccessible in steamed blue mussel. As for hydrophilic toxins, 100% of the initial content was bioaccessible after digestion in raw shellfish and puffer fish gonads. The total tetrodotoxin bioaccessibility in puffer fish gonads decreased significantly after steaming. The profile of tetrodotoxins changed during the digestion process: TTX and 11-norTTX-6S-ol analogues decreased significantly after digestion, but the 5,6,11-trideoxy TTX analogue increased in both raw and steamed puffer fish gonads. These preliminary findings confirm the need to consider bioaccessibility data in future seafood risk assessment, as such information enables a more accurate and realistic estimation of potential seafood hazards, particularly in what concerns lipophilic toxins, therefore, constituting a crucial tool in the refinement of regulatory limits for the presence of biotoxins in seafood.info:eu-repo/semantics/acceptedVersio
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