A green chemical oligomerization of phloroglucinol induced by plasma as novel α-glucosidase inhibitors

Inhibitory Effects of New Epicatechin Oligomers on Nitric Oxide Production

The primary aim of this research was to identify the structural characteristics of three newly derived procyanidins from cold plasma-treated (-)-epicatechin, known for their anti-inflammatory properties. The newly generated compounds were isolated through column chromatography, and their chemical structures were elucidated through spectroscopic data analyses, including both one-dimensional and two-dimensional nuclear magnetic resonance (NMR) and mass spectrometry (MS) techniques. Furthermore, their absolute configurations were determined via circular dichroism (CD) spectroscopy. The inhibitory activity of the isolated compounds on nitric oxide (NO) production and expression levels of inducible NO synthase (iNOS) in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages was evaluated. Three new procyanidins-methylenetrisepicatechin (2), isomethylenetrisepicatechin (3), and methylenebisepicatechin (4)-along with two reported dimeric flavan-3-ols (5 and 6), were identified from plasma-treated (-)-epicatechin (1). The unique oligomerized products 2 and 3 linked by methylene bridges significantly suppressed both NO production and iNOS expression, demonstrating higher anti-inflammatory activities in LPS-stimulated RAW 264.7 cells compared with the parent compound. The newly oligomerized procyanidins have potential applications in the treatment of inflammatory diseases owing to their significant anti-inflammatory properties.

Low-Temperature Plasma Techniques in Biomedical Applications and Therapeutics: An Overview

Plasma, the fourth fundamental state of matter, comprises charged species and electrons, and it is a fascinating medium that is spread over the entire visible universe. In addition to that, plasma can be generated artificially under appropriate laboratory techniques. Artificially generated thermal or hot plasma has applications in heavy and electronic industries; however, the non-thermal (cold atmospheric or low temperature) plasma finds its applications mainly in biomedicals and therapeutics. One of the important characteristics of LTP is that the constituent particles in the plasma stream can often maintain an overall temperature of nearly room temperature, even though the thermal parameters of the free electrons go up to 1 to 10 keV. The presence of reactive chemical species at ambient temperature and atmospheric pressure makes LTP a bio-tolerant tool in biomedical applications with many advantages over conventional techniques. This review presents some of the important biomedical applications of cold-atmospheric plasma (CAP) or low-temperature plasma (LTP) in modern medicine, showcasing its effect in antimicrobial therapy, cancer treatment, drug/gene delivery, tissue engineering, implant modifications, interaction with biomolecules, etc., and overviews some present challenges in the field of plasma medicine.

Innovative Application of Cold Plasma Technology in Meat and Its Products

The growing demand for sustainable food production and the rising consumer preference for fresh, healthy, and safe food products have been driving the need for innovative methods for processing and preserving food. In the meat industry, this demand has led to the development of new interventions aimed at extending the shelf life of meats and its products while maintaining their quality and nutritional value. Cold plasma has recently emerged as a subject of great interest in the meat industry due to its potential to enhance the microbiological safety of meat and its products. This review discusses the latest research on the possible application of cold plasma in the meat processing industry, considering its effects on various quality attributes and its potential for meat preservation and enhancement. In this regard, many studies have reported substantial antimicrobial efficacy of cold plasma technology in beef, pork, lamb and chicken, and their products with negligible changes in their physicochemical attributes. Further, the application of cold plasma in meat processing has shown promising results as a potential novel curing agent for cured meat products. Understanding the mechanisms of action and the interactions between cold plasma and food ingredients is crucial for further exploring the potential of this technology in the meat industry, ultimately leading to the development of safe and high-quality meat products using cold plasma technology.

Synthesis of Novel Methylsulfonylacrylimidamide via Click Chemistry Approach, Computational Analysis and α‐ Glucosidase Inhibition Activity

A series of Novel Methylsulfonylacrylimidamide analogs (4 a–4 h) were designed, synthesized, and screened for their α‐glucosidase inhibitory activity. The results indicated that some of the synthesized derivatives displayed inhibitory activities against α‐glucosidase with IC50 values ranging from 10.35±0.15 to 60.39±1.77 μM when compared to standard drug acarbose (IC50 832.22±2.00 μM). Among the synthesized derivatives, compounds 4 f and 4 h with a Di cyclohexyl and dioctyl substitution in the acrylimidamide displayed the most significant inhibitory activity with the IC50 value of 14.54±0.19 μM and 10.35±0.15 μM. The inhibitory action of compounds 4 f and 4 h against α‐glucosidase was studied by enzyme kinetic and molecular docking. In vitro, cytotoxicity showed that 4 f and 4 h exhibited low cytotoxicity against human cell lines. The ADME study suggested that most compounds will likely be orally active as they obeyed Lipinski's rule of five. Our studies showed that these derivatives could be considered a new class of α‐glucosidase inhibitors.

Plasma-Induced Oxidation Products of (-)-Epigallocatechin Gallate with Digestive Enzymes Inhibitory Effects

(-)-Epigallocatechin gallate (EGCG), the chief dietary constituent in green tea (Camellia sinensis), is relatively unstable under oxidative conditions. This study evaluated the use of non-thermal dielectric barrier discharge (DBD) plasma to improve the anti-digestive enzyme capacities of EGCG oxidation products. Pure EGCG was dissolved in an aqueous solution and irradiated with DBD plasma for 20, 40, and 60 min. The reactant, irradiated for 60 min, exhibited improved inhibitory properties against α-glucosidase and α-amylase compared with the parent EGCG. The chemical structures of these oxidation products 1-3 from the EGCG, irradiated with the plasma for 60 min, were characterized using spectroscopic methods. Among the oxidation products, EGCG quinone dimer A (1) showed the most potent inhibitory effects toward α-glucosidase and α-amylase with IC50 values of 15.9 ± 0.3 and 18.7 ± 0.3 μM, respectively. These values were significantly higher than that of the positive control, acarbose. Compound 1, which was the most active, was the most abundant in the plasma-irradiated reactant for 60 min according to quantitative high-performance liquid chromatography analysis. These results suggest that the increased biological capacity of EGCG can be attributed to the structural changes to EGCG in H2O, induced by cold plasma irradiation.

Novel Hybrid Molecules Based on (-)-Epigallocatechin Gallate as Potent Anti-adipogenic Agents

A series of novel (-)-epigallocatechin gallate (EGCG)-phloroglucinol hybrid compounds 1-4 has been successfully synthesized by employing a simple and efficient methodology using a dielectric barrier discharge (DBD) plasma irradiation. The new hybrid structures were determined by interpretation of spectroscopic data, with the absolute configurations being established by analysis of the circular dichroism (CD) spectra. The novel hybrids 1 and 2 showed highly improved anti-adipogenic potencies toward both pancreatic lipase and preadipocytes differentiation in 3T3-L1 compared to the original EGCG and phloroglucinol. A novel hybrid 1 represent an interesting subclass of anti-adipogenic candidates that need further research.

Applications and challenges of low temperature plasma in pharmaceutical field

Low temperature plasma (LTP) technology has shown an outstanding application value in the pharmaceutical filed in recent ten years. This paper reviews the research advances in LTP, including its effects on enhancing or inhibiting drug activity, its combined use with drugs to treat cancers, its effects on the improvement of drug delivery system, its use in preparation of new inactivated virus vaccines, its use with mass spectrometry for rapid detection of drug quality, and the anti-tumor and sterilization effects of plasma-activated liquids. The paper also analyzes the challenges of LTP in the pharmaceutical filed, hoping to promote related research.

Plasma-Polymerized Phlorotannins and Their Enhanced Biological Activities

Here, we investigated the effect of cold plasma (CP) on the biological activities of phloroglucinol. Phloroglucinol (7.92 and 15.84 mM in methanol) was treated with air dielectric barrier discharge plasma at 250 W. In vitro, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and ferrous-reducing antioxidant power (FRAP) values of phloroglucinol increased in plasma treatment in a time-dependent manner. CP treatment of phloroglucinol decreased the lipid oxidation of oil emulsion during storage and increased the antimicrobial activity against Bacillus cereus, Escherichia coli O157:H7, and Staphylococcus aureus. Angiotensin-converting enzyme (ACE) inhibitory activity of phloroglucinol increased and total phenolic content decreased based on CP treatment. The CP-induced polymerization of phloroglocinol to phlorotannin derivatives was identified using high-performance liquid chromatography with UV detector and electrospray ionization/mass spectrometry (HPLC-UV-ESI/MS) method. Consequently, the polymer structure of phloroglucinol was found in the CP-treated phloroglucinol. In addition, CP enhances the biological activity of phloroglucinol and could be applied to bioactive materials in food and related industries.

A new approach to procyanidins synthesis with potent anti-adipogenic effects

Convenient structure modification of (+)-catechin (1) induced by nonthermal dielectric barrier discharge (DBD) plasma treatment afforded three novel methylene-linked flavan-3-ol oligomers, methylenetetracatechin (2), methylenetricatechin (3), and methylenedicatechin (4), together with two known catechin dimers, bis 8,8'-catechinylmethane (5) and bis 6,8'-catechinylmethane (6). The structures of the three new catechin oligomers 2-4 with methylene bridges were elucidated by detailed 1D- and 2D-NMR analysis, and the absolute configurations were established by the observation of circular dichroism (CD). The novel products 2 and 3 showed significantly enhanced anti-adipogenic capacities against both pancreatic lipase and differentiation of 3T3-L1 preadipocytes compared to the parent (+)-catechin.