Antimicrobial and antibiofilm activities of citrus water-extracts obtained by microwave-assisted and conventional methods

Citrus pomace is a huge agro-food industrial waste mostly composed of peels and traditionally used as compost or animal feed. Owing to its high content of compounds beneficial to humans (e.g., flavonoids, phenol-like acids, and terpenoids), citrus waste is increasingly used to produce valuable supplements, fragrance, or antimicrobials. However, such processes require sustainable and efficient extraction strategies by solvent-free techniques for environmentally-friendly good practices. In this work, we evaluated the antimicrobial and antibiofilm activity of water extracts of three citrus peels (orange, lemon, and citron) against ten different sanitary relevant bacteria. Both conventional extraction methods using hot water (HWE) and microwave-assisted extraction (MAE) were used. Even though no extract fully inhibited the growth of the target bacteria, these latter (mostly pseudomonads) showed a significant reduction in biofilm biomass. The most active extracts were obtained from orange and lemon peel by using MAE at 100 °C for 8 min. These results showed that citrus peel water infusions by MAE may reduce biofilm formation possibly enhancing the susceptibility of sanitary-related bacteria to disinfection procedures

Microwave-Assisted Synthesis of (±)-Mandelic Acid-5 , ��tical Resolution, and A�solute Con�guration Deter�ination

An efficient microwave-assisted synthesis of (±)-mandelic acid-5 was developed. e racemic mixture was resolved by diastereomeric salt formation using 1-phenylethylamine enantiomers as resolving agents. At each step, the resolution process was checked by determining mandelic acid-5 enantiomer ee values directly on fractional crystallized diastereomeric salts by chiral capillary electrophoresis analysis. Highly enriched (−)-and (+)-mandelic acid-5 (95% and 90% ee, resp.) were obtained and their absolute con�gurations-and , respectively-were determined by correlation of the (−)-mandelic acid-5 circular dichroism spectrum to the (R)-mandelic acid one

Microwave-Assisted Extraction of Bioactive Compounds from Lentil Wastes: Antioxidant Activity Evaluation and Metabolomic Characterization

The recovery of industrial by-products is part of the zero-waste circular economy. Lentil seed coats are generally considered to be a waste by-product. However, this low-value by-product is rich in bioactive compounds and may be considered an eco-friendly source of health-promoting phytochemicals. For the first time, a sustainable microwave-assisted extraction technique was applied, and a solvent screening was carried out to enhance the bioactive compound content and the antioxidant activity of green and red lentil hull extracts. With respect to green lentil hull extracts that were obtained with different solvents, the aqueous extract of the red lentil seed coats showed the highest total phenolic and total flavonoid content (TPC = 28.3 ± 0.1 mg GAE/g dry weight, TFC = 1.89 ± 0.01 mg CE/100 mg dry weight, respectively), as well as the highest antioxidant activity, both in terms of the free radical scavenging activity (ABTS, 39.06 ± 0.73 mg TE/g dry weight; DPPH, IC50 = 0.39 μg/mL) and the protection of the neuroblastoma cell line (SH-SY5Y, IC50 = 10.1 ± 0.6 μg/mL), the latter of which has never been investigated so far. Furthermore, a metabolite discovery analysis was for the first time performed on the aqueous extracts of both cultivars using an HPLC separation which was coupled with an Orbitrap-based high-Resolution Mass Spectrometry technique

Recent trends in the discovery of small molecule blockers of sodium channels

Voltage-gated sodium channels (VGSC) are responsible for the selective influx of sodium ions in excitable cells. A number of physiological phenomena such as muscle contraction, pain sensation, processing of neuronal information in the brain as well as neuronal regulation of peripheral tissues rely on the activity of these channels. On the other hand, abnormal activity of VGSC are implicated in several pathological processes (e.g., cardiac arrhythmias, epilepsy, and chronic pain) which in some cases (e.g., channelopathies such as myotonias) are linked to specific gene mutations. As a result, VGSC have never stopped attracting the attention of medicinal chemists and the quest for novel drugs to treat these ion channels-associated diseases continues. In this review, VGSC blocking agents reported in the last lustrum are scrutinised with the aim to give a medicinal chemistry perspective on the most interesting compounds classified on the basis of (i) potential therapeutic application, (ii) targeted VGSC isoforms, and (iii) chemical scaffolds. Finally, the clinical potential of selected drug candidates from each chemotype is evaluated by comparing their ligand efficiency metrics. Possible routes for improvement of these preclinical candidates are also discussed

Ligand efficiency metrics in drug discovery: the pros and cons from a practical perspective

Introduction: Ligand efficiency metrics are almost universally accepted as a valuable indicator of compound quality and an aid to reduce attrition. Areas covered: In this review, the authors describe ligand efficiency metrics giving a balanced overview on their merits and points of weakness in order to enable the readers to gain an informed opinion. Relevant theoretical breakthroughs and drug-like properties are also illustrated. Several recent exemplary case studies are discussed in order to illustrate the main fields of application of ligand efficiency metrics. Expert opinion: As a medicinal chemist guide, ligand efficiency metrics perform in a context- and chemotype-dependent manner; thus, they should not be used as a magic box. Since the â\u80\u98big bangâ\u80\u99 of efficiency metrics occurred more or less ten years ago and the average time to develop a new drug is over the same period, the next few years will give a clearer outlook on the increased rate of success, if any, gained by means of these new intriguing tools

Discovery of a new mexiletine-derived agonist of the hERG K+channel

The human Ether-a-go-go Related Gene (hERG) potassium channel plays a central role in the rapid component (IKr) of cardiac action potential repolarization phase. A large number of structurally different compounds block hERG and cause a high risk of arrhythmias. Among the drugs that block hERG channel, a few compounds have been identified as hERG channel activators. Such compounds may be useful, at least in theory, for the treatment of long term QT syndrome. Here we describe a new activator of hERG channel, named MC450. This compound is a symmetric urea, derived from (R)-mexiletine. Using patch-clamp recordings, we found that MC450 increased the activation current of hERG channel, with an EC50of 41 ± 4 μM. Moreover MC450 caused a depolarizing shift in the voltage dependence of inactivation from â\u88\u92 64.1 ± 1.2 mV (control), to â\u88\u92 35.9 ± 1.4 mV, whereas it had no effect on the voltage dependence of activation. Furthermore, MC450 slowed current inactivation and the effect of MC450 was attenuated by the inactivation-impaired double mutant G628C/S631C

Preparation of (–)-(R)-2-(2,3,4,5,6-pentafluorophenoxy)-2-(phenyl-d5)acetic acid: an efficient 1H NMR chiral solvating agent for direct enantiomeric purity evaluation of quinoline-containing antimalarial drugs

The title compound was prepared as a racemate from (±)-mandelic acid-d5 in one step. The corresponding ()-(R)-enantiomer (98% ee) was obtained by resolution with ()-(R)-1-phenylethylamine and evaluated as a chiral solvating agent (CSA) for direct 1H NMR enantiomeric excess determination of mefloquine (Lariam), chloroquine (Chloroquine Bayer), and hydroxychloroquine (Plaquenil) enantiomers. The displayed non-equivalence was high for signals in the aromatic region of all three antimalarials. Thus, the mandelic acid derivative described herein may be considered as the first efficient CSA ‘invisible’ in the aromatic region, useful for direct 1H NMR ee value determination of chiral quinoline-containing antimalarial drugs

Capillary Zone Electrophoresis for Separation and Quantitative Determination of Mexiletine and its Main Phase I Metabolites

The simultaneous separation and quantification of the analytes within the minimum analysis time and the maximum resolution and efficiency are the main objectives in the development of a capillary electrophoretic method for the determination of solutes. In this paper we describe a specific, sensitive and robust method, using capillary zone electrophoresis with internal standard and UV detection, for the separation and quantification of the anti-arrhythmic drug mexiletine, its main phase I metabolites, and its main nitrogenous degradation product