Total Content and Composition of Phenolic Compounds from Filipendula Genus Plants and Their Potential Health-Promoting Properties.

This current article was dedicated to the determination of the composition of phenolic compounds in extracts of four species of the genus Filipendula in order to establish a connection between the composition of polyphenols and biological effects. A chemical analysis revealed that the composition of the extracts studied depended both on the plant species and its part (leaf or flower) and on the extractant used. All four species of Filipendula were rich sources of phenolic compounds and contained hydrolyzable tannins, condensed tannins, phenolic acids and their derivatives, and flavonoids. The activities included data on those that are most important for creating functional foods with Filipendula plant components: the influence on blood coagulation measured by prothrombin and activated partial thromboplastin time, and on the activity of the digestive enzymes (pancreatic amylase and lipase). It was established that plant species, their parts, and extraction methods contribute meaningfully to biological activity. The most prominent result is as follows: the plant organ determines the selective inhibition of either amylase or lipase; thus, the anticoagulant activities of F. camtschatica and F. stepposa hold promise for health-promoting food formulations associated with general metabolic disorders.

Effect of chlorogenic acid on the structural properties and digestibility of lotus seed starch during microwave gelatinization.

The structural evolution of lotus starch (LS)-chlorogenic acid (CA) complexes was investigated after microwave-heating treatment, to reveal the relationship between the interactions of lotus starch and chlorogenic acid molecules, and the digestive properties of the starch, after microwave gelatinization. During the early stage of microwave gelatinization (65, 70 °C), CA was mainly participating in the rearrangement of starch molecules in a weakly-bound form, and at that stage, the LS-CA complex acted as an inhibitor of digestion, under small intestine conditions, mainly through the release of CA, which inhibited amylase. However, during the late stage of microwave gelatinization (85 °C), many chlorogenic acid molecules entered the hydrophobic helical cavity of the starch, promoting formation of the V-type starch helical structure in the LS-CA complex, which made a major contribution to inhibiting digestion under oral digestion conditions.

A Prospective of Multiple Biopharmaceutical Activities of Procyanidins-Rich Uapaca togoensis Pax Extracts: HPLC-ESI-TOF-MS Coupled with Bioinformatics Analysis.

The article reports the chemical composition, antioxidant, six key enzymes inhibitory and antimicrobial activities of two solvent extracts (water and methanol) of leaves and stem bark of Uapaca togoensis. For chemical composition, methanol extract of stem bark exhibited significant higher total phenolic (129.86 mg GAE/g) and flavanol (10.44 mg CE/g) contents. Methanol extract of leaves and water extract of stem bark showed high flavonoids (20.94 mg RE/g) and phenolic acid (90.40 mg CAE/g) content, respectively. In addition, HPLC-ESI-TOF-MS analysis revealed that U. togoensis was rich in procyanidins. The methanol and water extracts of stem bark had overall superior antioxidant activity; however, only methanol extract of stem bark showed higher inhibition of cholinesterase (AChE: 2.57 mg GALAE/g; BChE: 4.69 mg GALAE/g), tyrosinase (69.53 mg KAE/g) and elastase (2.73 mmol CE/g). Potent metal chelating ability was showed by water extract of leaves (18.94 mg EDTAE/g), higher inhibition of amylase was detected for water extracts of leaves (0.94 mmol ACAE/g) and stem bark (0.92 mmol ACAE/g). The tested extracts have shown wide-spectrum antibacterial properties and these effects have shown to be more effective against Aspergillus ochraceus, Penicillium funiculosum, Trichoderma viride, Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. The results revealed that the antioxidant, enzyme inhibitory and antimicrobial activities depended on the extraction solvents and the parts of plant. Bioinformatics analysis on the 17 major compounds showed modulation of pathway associated with cancer. In brief, U. togoensis might be valuable as potential source of natural agents for therapeutic application.

Synthesis of novel 5-(2,5-bis(2,2,2-trifluoroethoxy)phenyl)-1,3,4-oxadiazole-2-thiol derivatives as potential glucosidase inhibitors.

BACKGROUND: A hybrid molecule of different biologically active substances can improve affinity and efficiency compared to a standard drug. Hence based on this fact, we predict that a combination of fluorine, oxadiazole, sulfur, etc., may enhance α-glucosidase inhibition activity compared to a standard drug. METHODS: A series of novel 5-(2,5-bis(2,2,2-trifluoroethoxy)phenyl)-1,3,4-oxadiazole-2-thiol derivatives (2a-2i) were synthesized and characterized using spectroscopic techniques such as 1HNMR and LC-MS. In order to evaluate its bioactivity, in vitro α-amylase and α-glycosidase inhibitory activity were performed. In vivo study was carried using a genetic model, Drosophila melanogaster, for assessing the antihyperglycemic effects. RESULTS: The compounds 2a-2i demonstrated α-amylase inhibitory activity in the range of IC50 = 40.00-80.00 µg/ml as compare to standard acarbose (IC50 = 34.71 µg/ml). Compounds 2a-2i demonstrated α-glucosidase inhibitory activity in the range of IC50 = 46.01-81.65 µg/ml as compared to standard acarbose (IC50 = 34.72 µg/ml). Docking studies on a target protein, N-terminal subunit of human Maltase-glucoamylase (PDB:2QMJ) was carried and the compounds were found to dock into the active site of the enzyme (Fig. 1). The predicted binding energies of the compounds were calculated. The in vitro studies indicate that compounds 2b and 2g had better activity among the synthesized compounds. Whereas in vivo study indicates that 2b, 2g, and 2i could lower glucose levels in the Drosophila, but then 17-30% reduced capacity than acarbose and may be overcome by adjusting their dosage. CONCLUSIONS: The in vitro and in vivo studies indicate that compounds 2b and 2g had better activity among the synthesized compounds. This study has recognized that compounds like 2b, 2g, and 2i may be considered potential candidates for further developing a novel class of antidiabetic agents.

Structural changes of rice starch and activity inhibition of starch digestive enzymes by anthocyanins retarded starch digestibility.

The effects of anthocyanins on in vitro and in vivo digestibility of rice starch were evaluated in this study. Then, the effects of anthocyanins on physicochemical properties of rice starch and on starch digestive enzymes (α-amylase and α-glucosidase) were investigated to understand the mechanism of the effects of anthocyanins on starch digestibility. Characterization of physicochemical properties of rice starch indicates a structural change due to the presence of anthocyanins, hindering its access to starch digestive enzymes. Besides, anthocyanins inhibited the activities of starch digestive enzymes by binding to their active sites, competing with the substrates and changing the secondary structure of the enzymes. The above stated changes of rice starch and starch digestive enzymes due to the presence of anthocyanins both contributed to retarding the digestibility of rice starch. This study could offer some theoretical guidance to the development of new type rice-based food with low glycemic index.

GC/MS Profiling, In Vitro and In Silico Pharmacological Screening and Principal Component Analysis of Essential Oils from Three Exotic and Two Endemic Plants from Mauritius.

The chemical and pharmacological profiles of essential oils (EOs) hydrodistilled in yields of 0.03-0.77 % (w/w) from three exotic (Cinnamomum camphora, Petroselinum crispum, and Syzygium samarangense) and two endemic (Pittosporum senacia subsp. senacia and Syzygium coriaceum) medicinal plants were studied. GC-MS/GC-FID analysis of the EOs identified the most dominant components to be myristicin (40.3 %), myrcene (62.2 %), 1,8-cineole (54.0 %), ß-pinene (21.3 %) and (E)-ß-ocimene (24.4 %) in P. crispum, P. senacia and C. camphora, S. samarangense and S. coriaceum EOs, respectively. All EOs were found to possess anti-amylase (0.70-1.50 mM ACAE/g EO) and anti-tyrosinase (109.35-158.23 mg KAE/g) properties, whereas no glucosidase inhibition was displayed. Only Syzygium EOs acted as dual inhibitors of both acetyl- and butyryl-cholinesterases, while P. senacia and C. camphora EOs inhibited acetylcholinesterase selectively and P. crispum EO was inactive (AChE: 4.64-4.96 mg GALAE/g; BChE: 5.96 and 7.10 mg GALAE/g). Molecular docking revealed 1,8-cineole to present the best binding affinities with butyrylcholinesterase, amylase and tyrosinase, while both myristicin and ß-pinene with acetylcholinesterase and finally ß-pinene with glucosidase. In vitro antioxidant potency was also demonstrated in different assays (DPPH: 13.52-53.91 mg TE/g, ABTS: 5.49-75.62 mg TE/g; CUPRAC: 45.38-243.21 mg TE/g, FRAP: 42.49-110.64 mg TE/g; and phosphomolybdenum assay: 82.61-160.93 mM TE/g). Principal component analysis revealed the EOs to differ greatly in their bioactivities due to their chemodiversity. This study has unveiled some interesting preliminary pharmacological profiles of the EOs that could be explored for their potential applications as phytotherapeutics.

Comparative study on the chemical composition and biological activities of the essential oils of three Lagochilus species collected from Uzbekistan.

Lagochilus species are mainly distributed in Central Asia and widely used in folk medicine as a sedative and haemostatic. The present investigation reports on the extraction by hydrodistillation and the chemical composition of three Lagochilus species (L. gypsaceus, L. inebrians and L. setulosus) essential oils from Uzbekistan. The chemical composition of these essential oils was determined by GC-MS. The results showed that the studied essential oils are made up mainly of linalool (11.97%), ß-ionone (11.75%), trans-chrysanthenyl acetate (7.15%), α-terpineol (7.40%) for L. gypsaceus; trans-chrysanthenyl acetate (9.40%), eugenol (7.01%), trans-verbenol (3.85%), bicyclo[3.1.1]hept-3-en-2-one (3.76%), pinocarvone (3.43%) for L. inebrians; and finally 2,4-bis(1,1-dimethylethyl)phenol (19.78%), bicyclo[3.1.1]hept-2-en-4-ol (5.43%), hexadecanoic acid (5.39%), limonene (5.19%), 2-hexenal (5.03%) for L. setulosus. The best antioxidant and tyrosinase inhibitory activity was observed for the essential oil of L. inebrians. However, L. setulosus essential oil exhibited the strongest inhibitory effect against amylase.

Supercritical and ultrasound-assisted extracts from Pleurotus pulmonarius mushroom: chemical profiles, antioxidative, and enzyme-inhibitory properties.

BACKGROUND: This study provides an insight into the impact of ultrasound-assisted extraction with water as solvent (UAEW) and extraction by supercritical carbon dioxide (SC-CO2 ) with 5% EtOH on antioxidant and enzyme inhibitory activity in regard to the chemical profile of the edible and medicinal mushroom, Pleurotus pulmonarius. RESULTS: Extraction efficiency was between 0.36% and 63.32%, depending on the extraction technique. The main compounds in the extracts were fatty acids. Supercritical CO2 extraction with co-solvent was the most suitable method for obtaining extracts that were rich in ergosterol content, reaching a value of 40.1 mg g-1 . The UAEW of crude mushroom powder ensured the highest yield, as well as the extracts with best antioxidative activity. The measurements of enzyme inhibitory activity revealed that all types of investigated extracts exhibited only tyrosinase and amylase inhibition at a significant level. CONCLUSION: Based on our results, the extraction methods significantly affected the chemical profile and bioactivity of P. pulmonarius. © 2020 Society of Chemical Industry.

Antiamylase, Antilipase, Antimicrobial, and Cytotoxic Activity of Nonea obtusifolia (Willd.) DC. from Palestine.

BACKGROUND: Medicinal plants are widely used in many cultures, traditions, and civilizations worldwide. Plants with high contents of the valuable biological compounds can efficiently cure many diseases. This study is aimed at assessing, for the first time, the anti-α-amylase, antilipase, antimicrobial, and cytotoxic activities of Nonea obtusifolia (Willd.) DC. of five extracts from Palestine. METHODS: The antimicrobial activity was estimated using well diffusion method for N. obtusifolia plant of five extracts against eight ATCC (American Type Culture Collection) and clinical isolates. The cytotoxic effects for these extracts were evaluated against HeLa (cervical) carcinoma cells using MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. Moreover, the lipase and α-amylase inhibitory properties were determined using standard biomedical assays. RESULTS: The acetone extract of N. obtusifolia plant showed a more potent α-amylase inhibitory compared with acarbose with IC50 values of 25.7 ± 0.08 and 28.18 ± 1.22 µg/ml, respectively. Additionally, the acetone and methanol extracts revealed moderate antilipase activity compared to orlistat with IC50 values of 30.19 ± 0.11, 33.11 ± 0.13, and 12.3 ± 0.35 µg/ml, respectively. The methylene chloride extract was found to inhibit the growth of all the tested bacterial and fungal strains and also found to have potential cytotoxic effect against HeLa cancer cell line. CONCLUSION: This research work reports for the first time the biological activity of N. obtusifolia from Palestine, and the results were promising indicating that N. obtusifolia extracts contain valuable bioactive molecules that have a potential anti-α-amylase, antilipase, antibacterial, and antifungal cytotoxic potentials. Therefore, N. obtusifolia could have a medical significance in the future.

Is Gluten the Only Culprit for Non-Celiac Gluten/Wheat Sensitivity?

The gluten-free diet (GFD) has gained increasing popularity in recent years, supported by marketing campaigns, media messages and social networks. Nevertheless, real knowledge of gluten and GF-related implications for health is still poor among the general population. The GFD has also been suggested for non-celiac gluten/wheat sensitivity (NCG/WS), a clinical entity characterized by intestinal and extraintestinal symptoms induced by gluten ingestion in the absence of celiac disease (CD) or wheat allergy (WA). NCG/WS should be regarded as an "umbrella term" including a variety of different conditions where gluten is likely not the only factor responsible for triggering symptoms. Other compounds aside from gluten may be involved in the pathogenesis of NCG/WS. These include fructans, which are part of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), amylase trypsin inhibitors (ATIs), wheat germ agglutinin (WGA) and glyphosate. The GFD might be an appropriate dietary approach for patients with self-reported gluten/wheat-dependent symptoms. A low-FODMAP diet (LFD) should be the first dietary option for patients referring symptoms more related to FODMAPs than gluten/wheat and the second-line treatment for those with self-reported gluten/wheat-related symptoms not responding to the GFD. A personalized approach, regular follow-up and the help of a skilled dietician are mandatory.

Comparative quantitative LC-MS/MS analysis of 13 amylase/trypsin inhibitors in ancient and modern Triticum species.

Amylase/trypsin inhibitors (ATIs) are major wheat allergens and they are also implicated in causing non-celiac gluten sensitivity and worsening other inflammatory conditions. With only few studies on ATI contents in different Triticum species available so far, we developed a targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) method based on stable isotope dilution assays to quantitate the 13 most important ATIs in a well-defined sample set of eight cultivars of common wheat and durum wheat (modern species), as well as spelt, emmer and einkorn (ancient species) grown at three locations in Germany, respectively. Only few ATIs with low contents were detected in einkorn. In contrast, spelt had the highest total ATI contents. Emmer and common wheat had similar total ATI contents, with durum wheat having lower contents than common wheat. Due to the lack of correlation, it was not possible to estimate ATI contents based on crude protein contents. The wheat species had a higher influence on ATI contents than the growing location and the heritability of this trait was high. Despite comparatively low intra-species variability, some cultivars were identified that may be promising candidates for breeding for naturally low ATI contents.

Synthesis of bio-mediated silver nanoparticles from Silybum marianum and their biological and clinical activities.

The purpose of current study was green synthesis of silver nanoparticles (AgNPs) from seeds and wild Silybum plants in comparison with their respective extracts followed by characterization and biological potency. The biologically synthesized AgNPs were subjected to characterization using techniques like XRD, FTIR, TEM, HPLC and SPE. Highly crystalline and stable NPs were obtained using Silybum wild plant (NP1) and seeds (NP3) with size range between 18.12 and 13.20 nm respectively. The synthesized NPs and their respective extracts revealed a vast range of biological applications showing antibacterial, antioxidant, anti-inflammatory, cytotoxic and anti-aging potencies. The highest antioxidant activity (478.23 ± 1.9 µM, 176.91 ± 1.3 µM, 83.5 ± 1.6% µgAAE/mg, 156.32 ± 0.6 µgAAE/mg) for ABTS, FRAP, FRSA, TRP respectively was shown by seed extract (NP4) followed by highest value of (117.35 ± 0.9 µgAAE/mg) for TAC by wild extract (NP2). The highest antifungal activity (13 mm ± 0.76) against Candida albicans was shown by NP3 while antibacterial activity of (6 mm against Klebsiella pneumonia) was shown by NP3 and NP4. The highest anti-inflammatory activity (38.56 ± 1.29 against COX1) was shown by NP2. Similarly, the high value of (48.89 ± 1.34 against Pentosidine-Like AGEs) was shown by NP4. Also, the high anti-diabetic activity (38.74 ± 1.09 against α-amylase) was shown by NP4. The extracts and the synthesized NPs have shown activity against hepato-cellular carcinoma (HepG2) human cells. The HPLC analysis revealed that the highest value of silymarin component (silybin B 2289 mg/g DW) was found for NP4. Silydianin is responsible for capping. Among the green synthesized AgNPs and the extracts used, the effect of NP4 was most promising for further use.

Ellipticine blocks synergistic effects of IL-17A and TNF-α in epithelial cells and alleviates severe acute pancreatitis-associated acute lung injury.

IL-17A combined with TNF-α plays a vital role in inflammatory response and interference of the synergistic effect is an effective strategy for treating inflammatory diseases. Ellipticine, a natural alkaloid, has biological activities on anti-tumor and anti-HIV. However, it is still unknown whether ellipticine can inhibit IL-17A and TNF-α-mediated signaling and has treatment effect on PALI. Here, we reported that ellipticine significantly inhibited the production of pro-inflammatory cytokines and chemokines in pulmonary epithelial cell BEAS-2B treated with IL-17A and TNF-α, but not IL-17A or TNF-α alone. Meanwhile, ellipticine attenuated NF-κB and MAPKs activation in response to IL-17A and TNF-α treatment, inhibited Act1 and TRAF6-mediated NF-κB activation, and blocked the interaction of Act1 with TRAF6. Furthermore, we found that ellipticine significantly alleviated CAE and LPS-induced SAP/PALI. Ellipticine treatment dramatically reduced inflammatory cells infiltration, MPO activity, serum amylase and lipase activity and the protein concentration of BALF. Collectively, our findings indicate that ellipticine inhibits the synergistic effect of IL-17A and TNF-α by targeting on Act1 and TRAF6 interaction and is a potential therapeutic agent for the treatment of SAP/PALI.

Chemical characterization of the antioxidant, antihyperglycemic and antihypertensive capacities of red rice (Oryza sativa L. ) whole flour / Caracteristicas físico-químicas, capacidad antioxidante, anti-hiperlucémica y antihipertensiva de la harina de arroz rojo (Oryza sativa L. )

Oryza sativa L. rice has large amounts of proteins and minerals, besides presenting several pigmented varieties. Red rice is distinguishable due to its great nutritional value compared to the regular white variety. Its red pericarp pigmentation is due to the bioactive compounds that are responsible for its health benefits. The objective of this study was to evaluate the physical-chemical characterization, antioxidant, antihyperglycemic and antihypertensive capacity of flours of three different red rice cultures (Rubi, Virgínia and Pequeno). All samples presented specific levels of carbohydrates for cereals with low fat content and excellent levels of protein and resistant starch. In addition, the samples had a high antioxidant, antihyperglycemic and antihypertensive capacity. Antihyperglycemic capacities were measured as percent inhibition for amylase (56.7-76.5%) and glycosidase (81.0-76.6%), respectively, and antihypertensive capacity as the percentage inhibition of the angiotensin converting enzyme (38.4-34.7%). In addition, Pequeno flour presented the best results for antioxidant and antihyperglycemic capacity in comparison to the two flours tested. Thus, all red rice flours can be a source of functional compounds when added to food.

El arroz integral (Oryza sativa L.) posee importantes cantidades de proteínas, vitaminas, minerales y fitoquímicos. El arroz rojo se destaca por su gran valor nutricional. La pigmentación roja del pericarpio está asociado al contenido de compuestos bioactivos, que están directamente relacionados a los beneficios de salud humana. Teniendo en cuenta lo antes expuesto se propuso evaluar las caracteristicas físico-químicas, capacidad antioxidante, anti-hiperglucémica y antihipertensiva de las harinas de tres diferentes cultivos de arroz rojo (Rubí, Virginia y Pequeño). Todas las muestras presentaron niveles específicos de carbohidratos para cereales con bajo contenido de grasa y altos contenidos de proteína y almidón resistente. Además, las muestras presentaron una alta capacidad antioxidante, anti-hiperglucémica y antihipertensiva. La capacidad anti-hiperglicémica se midió en porcentaje de inhibidores de α-amilasa (56.7-76.5%) y α-glucosidasa (81.0-76.6%), respectivamente; y capacidad antihipertensiva como el porcentaje de inhibición de la enzima convertidora de la angiotensina (38.4-34.7%). El cultivar Pequeño presentó mayor capacidad antioxidante y anti-hiperglucémica en comparación a los demás cultivares. Así, todas las harinas de arroz rojo pueden ser vehículos de compuestos funcionales en los alimentos.

Structure-based design of human pancreatic amylase inhibitors from the natural anthocyanin database for type 2 diabetes.

Human Pancreatic Amylase (HPA) is an important target for prevention and treatment of type 2 diabetes. Acarbose is a currently available drug acting as a HPA inhibitor, but its gastrointestinal side-effects cannot be neglected. Thus, developing novel HPA inhibitors with no side-effects is of great importance. Herein, we adopted a structure-based design approach and discovered a potent HPA inhibitor, malvidin 3-O-arabinoside (M3A), from the natural anthocyanin database. We identified M3A as an effective HPA inhibitor through virtual screening, enzyme activity and enzyme kinetic assays. We reported the structure and activity relationships as both the anthocyanidin core and glucosyl group affected the HPA inhibitory effect of anthocyanins. Molecular dynamics studies indicated that the HPA inhibition of M3A occurred via its binding to the HPA key catalytic residues Arg195 and Asp197 through stable hydrogen bonding. In addition, M3A was found to reduce α-helix fractions and increase ß-sheet fractions in CD spectrometry. Further in vivo studies showed that M3A significantly ameliorated the postprandial blood glucose level. Taken together, our results provide new insights into the development of novel HPA inhibitors from natural sources as food supplements for type 2 diabetes.

Comparison on characterization and biological activities of Mentha haplocalyx polysaccharides at different solvent extractions.

This study aimed to compare the effects of four solvent extractions on the physicochemical properties, antioxidant and hypoglycemic activities of polysaccharides from Mentha haplocalyx (MHPs). The solvent extractions included hot water, citric acid (pH 3.0), 5% NaOH/0.05% NaBH4 and 0.9% NaCl. Four corresponding MHPs named as MHP-W, MHP-C, MHP-A and MHP-S were obtained, respectively. The experimental results showed that the extraction yields, basic chemical components, monosaccharide contents, molecular weights, antioxidant and hypoglycemic activities of four MHPs were significantly different. However, their thermal stabilities, preliminary structural characteristics and monosaccharide types were similar. MHP-A possessed the highest extraction yield of 9.37 ± 0.24% and the smallest molecular weight. MHP-W had the highest uronic acid content and the largest molecular weight. More specifically, MHP-C exhibited the highest sugar content, the most remarkable antioxidant abilities of DPPH radical scavenging activity and ferric reducing power, and the strongest inhibitory activities on α-glucosidase and α-amylase. The above results indicated that MHP-C extracted with citric acid could be served as a promising bioactive substance for applications in the functional food and medicine industries.

Effect of silver doping on antidiabetic and antioxidant potential of ZnO nanorods.

BACKGROUND: Increasing resistance to available drugs and their associated side-effects have drawn wide attention towards designing alternative therapeutic strategies for control of hyperglycemia and oxidative stress. The roles of the sizes and shapes of the nanomaterials used in the treatment and management of Type 2 Diabetes Mellitus (T2DM) in preventing chronic hyperglycaemia and oxidative stress are investigated. We report specifically on the effects of doping silver (Ag) into the ZnO nanorods (ZnO:Ag NR's) as a rational drug designing strategy. METHODS: Inhibition of porcine pancreatic α-amylase, murine pancreatic amylase, α-glucosidase, murine intestinal glucosidase and amyloglucosidase are checked for evaluation of antidiabetic potential. In addition, the radical scavenging activities of ZnO:Ag NR's against nitric oxide, DDPH and superoxide radicals are evaluated. RESULTS: Quantitative radical scavenging and metabolic enzyme inhibition activities of ZnO:Ag NR's at a concentration of 100 µg/mL were found to depend on the amount of Ag doped in up to a threshold level (3-4 %). Circular dichroism analysis revealed that the interaction of the NR's with the enzymes altered their secondary conformation. This alteration is the underlying mechanism for the potent enzyme inhibition. CONCLUSIONS: Enhanced inhibition of enzymes and scavenging of free radicals primarily responsible for reactive oxygen species (ROS) mediated damage, provide a strong scientific rationale for considering ZnO:Ag NR's as a candidate nanomedicine for controlling postprandial hyperglycaemia and the associated oxidative stress.

Isolation of polyphenol compounds from olive waste and inhibition of their derivatives for α-glucosidase and α-amylase.

Olive waste was used as a sustainable resource because it contained a variety of valuable compounds. The polyphenols active fraction from enrichment by microporous resin and extraction with ethyl acetate were analysed by different chromatographic methods. A total of 14 polyphenolic compounds were isolated and identified by structure elucidation. Based on the above obtained compounds, tyrosol was selected as a characteristic polyphenol and participated in transesterification reaction to synthesise ß-ketoester using Yb(OTf)3. Then the Biginelli reaction with benzaldehyde, urea and ketoester (1:1.2:1.2) was performed at 90 °C for 3.0 h under the acidic condition. In addition, the ß-ketoester prepared using tyrosol with benzyl had a greater inhibitory effect on α-glucosidase and α-amylase, and the inhibition of enzyme activity for 3, 4-dihydropyrimidinone derivatives prepared using abovementioned ß-ketoester was improved significantly. Meanwhile, fluorine-containing dihydropyrimidinone derivatives were considerable inhibitors for both enzymes.

Untargeted and targeted metabolomics reveal the chemical characteristic of pu-erh tea (Camellia assamica) during pile-fermentation.

Pile-fermentation is the most important process of producing ripened pu-erh tea. To study the chemical changes of tea leaves during pile-fermentation (PF), liquid chromatography coupled with tandem mass spectrometry (LC-MS) was used. Untargeted metabolomics analysis revealed that the first stage of PF is crucial in transforming the original secondary metabolites, whereas the contents of flavan-3-ols and gallic acid were decreased after long-term PF. Targeted metabolomics analysis indicated that the levels of puerins (N-ethyl-2-pyrrolidinone substituted gallocatechin and catechin) were significant increased after the first stage of PF, but after long-term PF the levels of flavonol glycosides, procyanidins and galloylated flavan-3-ols were significantly decreased. Accordingly, long-term PF also decreased the inhibition of α-amylase and α-glucosidase activities of the extracts. As a conclusion, pile-fermentation is an important step of changing the polyphenols and bioactivities of pu-erh tea.

Plant α-amylase inhibitors and their effect on the utilization of polysaccharides contained in the diet.

Development of civilization diseases such as diabetes mellitus, metabolic syndrome or obesity, enforces the increasing effort to find new drugs, especially from natural sources. These include α-amylase inhibitors, which break down polysacharides into simple sugars in the body of a healthy person. As this cleavage affects the level of blood sugar, which is sought to be therapeutically influenced, there is a growing interest in these substances. This review maps the types of amylase inhibitors, including their natural resources.