Higher Α-glucosidase Inhibition Research Articles

Enzymatic synthesis of Artemisia capillaris-derived prebiotic oligosaccharide using Leuconostoc mesenteroides MKSR dextransucrase and its potential health functional effects

This study focuses on the enzymatic synthesis of prebiotic oligosaccharide from Artemisia capillaris (AC) using Leuconostoc mesenteroides MKSR dextransucrase and explores their antidiabetic, antidementia, and antioxidant effects through in vitro experiments. A Box-Behnken design was used to optimize transglycosylation conditions to produce Artemisia capillaris-derived oligosaccharide (ACOD) containing isomaltooligosaccahrides (IMO), dextran, and A. capillaris-derived substances with high α-glucosidase inhibition (AGI). The optimized conditions were 3.62 brix of AC, 182.54 mM sucrose, and 11.304 mM maltose. ACOD completely inhibited α-glucosidase activity, with 1.52-fold increase compared to other samples, such as OD (IMO and dextran, transglycosylated by dextransucrase without AC) and AC + OD (a simple mixture of AC and OD). Additionally, ACOD showed noteworthy acetylcholinesterase (103.91%) and butyrylcholinesterase (103.30%) inhibitory activity and potent antioxidant properties in terms of DPPH radical scavenging activity (70.04%), reducing power (100%), and ferric reducing antioxidant power (FRAP). ACOD (3.60) showed a higher prebiotic index compared with AC (-23.11), OD (-2.27), and AC + OD (-9.12). In conclusion, ACOD offers enhanced multi-biological activities as a potential health-functional prebiotic. These findings hold promise for applications in functional foods and pharmaceuticals, expanding our understanding of prebiotic functionality.

Evaluating the Antioxidant and Antidiabetic Properties of Medicago sativa and Solidago virgaurea Polyphenolic-Rich Extracts.

The present study evaluated the antioxidant and antidiabetic properties of Medicago sativa and Solidago virgaurea extracts enriched in polyphenolic compounds. The extracts were obtained by accelerated solvent extraction (ASE) and laser irradiation. Then, microfiltration was used for purification, followed by nanofiltration used to concentrate the two extracts. The obtained extracts were analyzed to determine their antioxidant activity using DPPH radical scavenging and reducing power methods. The antidiabetic properties have been investigated in vitro on a murine insulinoma cell line (β-TC-6) by the inhibition of α-amylase and α-glucosidase. M. sativa obtained by laser irradiation and concentrated by nanofiltration showed the highest DPPH• scavenging (EC50 = 105.2 ± 1.1 µg/mL) and reducing power activities (EC50 = 40.98 ± 0.2 µg/mL). M. sativa extracts had higher inhibition on α-amylase (IC50 = 23.9 ± 1.2 µg/mL for concentrated extract obtained after ASE, and 26.8 ± 1.1), while S. virgaurea had the highest α-glucosidase inhibition (9.3 ± 0.9 µg/mL for concentrated extract obtained after ASE, and 8.6 ± 0.7 µg/mL for concentrated extract obtained after laser extraction). The obtained results after evaluating in vitro the antidiabetic activity showed that the treatment with M. sativa and S. virgaurea polyphenolic-rich extracts stimulated the insulin secretion of β-TC-6 cells, both under normal conditions and under hyperglycemic conditions as well. This paper argues that M. sativa and S. virgaurea polyphenolic-rich extracts could be excellent natural sources with promising antidiabetic potential.

Bassia longifolia (= Madhuca longifolia): Isolation of flavan-3-ols and their contribution to the antibacterial and antidiabetic activity in vitro

Bassia longifoliaKOENIG (= Madhuca longifolia (L.) is an evergreen tree that is widely distributed throughout Nepal, India, and Sri Lanka. The bark has various traditional uses: as a paste in the treatment of cuts and wounds or internally as a decoction that is given to diabetic patients. Chemical-analytical and pharmacological investigations regarding the bark are not sufficiently available. We focused on the isolation of flavan-3-ols from the methanolic extract and their contribution to the described traditional uses in wound healing and diabetes treatment. Therefore, an antibacterial assay and an α-glucosidase assay were performed. The isolation process was performed by a combination of Sephadex®-, MCI®-Gel-, and RP-18 chromatography. The structures of the isolated compounds were elucidated by 1H- and 13C-NMR-spectroscopy including COSY, ROESY, HSQC, and HMBC methods. Optical characterization was performed by polarimetry and circular dichroism. Two monomeric, seven dimeric, six trimeric, and one tetrameric flavan-3-ols were found including one dimer and three trimers with rare epiafzelechin units. Two compounds were isolated for the first time. A fraction containing higher oligomeric and polymeric proanthocyanidins (PAs) was examined by 13C NMR spectroscopy and revealed an average degree of polymerization of 8–9. PA with cis-configurated subunits predominated at 90 % and the presence of further monohydroxylated flavan-3-ols was revealed. Minimal inhibitory concentrations (MICs) were investigated by the serial microdilution broth assay with Staphylococcus aureus. The bacterial suspension was inoculated on agar plates for determining the MICs. The α-glucosidase assay was performed in 96 well plates with α-glucosidase from Bacillus stearothermophilus. For the detection of enzyme inhibition, p-nitrophenyl-α-d-glucopyranoside was used as a substrate and after incubation absorbance was measured at 405 nm. Antibacterial effects were only found for fractions enriched with PAs or containing higher oligomeric and polymeric flavan-3-ols. All tested substances showed high α-glucosidase inhibition. Whereby 4β→8 conjugated dimers and the monomers showed the lowest inhibition, procyanidin (PC) B5 as 4β→6 conjugated and cinnamtannin A2 as tetrameric flavan-3-ol showed the highest. PAs with epiafzelechin units are rarely found in nature but their reoccurring appearance in B. longifolia could be characteristic of this plant. For its traditional uses, the antibacterial activity of the PA-enriched fractions could contribute to the wound healing process when applied to the injured skin. Moreover, all tested substances and fractions showed α-glucosidase inhibition, which could also explain the use of a decoction in the treatment of diabetes. In conclusion, pharmacological investigations could provide scientific evidence for traditional uses of B. longifolia.

Bioactive potential of ripened white cheeses manufactured in different geographical regions of Turkey.

This study investigated the potential bioactive properties of white cheeses produced in different regions of Turkey, including their potential antioxidant, antihypertensive, antidiabetic, antimicrobial, and anticancer activities. The cheese samples were analyzed both before and after in vitro digestion. The study found that all cheese samples exhibited significant angiotensin-converting enzyme inhibition activity both before (45.5%-70.1% for 0.03gcheese/mL) and after in vitro digestion (25.5%-63.5% for 0.0167g cheese/mL), whereas α-amylase inhibition activity was present in all samples (in the range of 5.1%-50.0% for 3.0×10-5 gcheese/mL) but disappeared after digestion, and α-glucosidase inhibition activity was only detected after in vitro digestion (from 20.5% to 60.4% for 5.6×10-5 gcheese/mL), indicating potential antidiabetic properties. However, antimicrobial and anticancer activities were not observed in any of the samples. The results also suggest that the bioactivity potential of white cheese may vary depending on the region of production, as cheeses from the Marmara region exhibited high α-glucosidase inhibition activity after digestion. In conclusion, while white cheese is a valuable addition to the diet due to its high nutritional value and potential health benefits. This study revealed the bioactive potential of ripened white cheese and in vivo investigations of the cheese components would better show their possible benefits. PRACTICAL APPLICATION: Although the bioactivity potentials varied among the ripened white cheese samples produced in different regions of Turkey, a consistent trend was observed in terms of their presence or absence. Our research revealed that all ripened cheese samples demonstrated significant potential antioxidant and antihypertensive activities, as well as potential antidiabetic properties. Moreover, it can be interpreted that ripened white cheese has the potential to reduce the digestion of carbohydrates when consumed with carbohydrate-rich foods. Although the present results provide limited practical findings directly applicable to the industry, if the data and information obtained from this study are further explored and further studies delving into specific mechanisms of bioactive components could emerge.

Sericin mediated gold/silver bimetallic nanoparticles and exploration of its multi-therapeutic efficiency and photocatalytic degradation potential

The current investigation aimed at bimetallic gold-silver nanoparticles (Au/Ag NPs), here called BM-GS NPs, synthesis using sericin protein as the reducing agent in an easy, cost-effective, and sustainable way. The obtained BM-GS NPs were characterized by UV–Visible spectroscopy, Transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDS), atomic force microscopy (AFM), Dynamic light scattering (DLS) and Zeta potential, X-ray Powder Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and Thermogravimetric analysis followed by evaluation of its multitherapeutic and photocatalytic degradation potentials. The TEM analysis revealed its spherical nature and the EDS result displayed the presence of both Ag and Au elements, confirming the synthesis of BM-GS NPs. The XRD pattern verified the crystalline nature of the nanoparticles (NPs). The DLS analysis showed an average size of 86.08 d nm and the zeta potential showed a highly negative value (−26.3 mV) which specifies that the generated bimetallic NPs are stable. The BM-GS NPs exhibited positive wound healing potential (with 63.38% of wound closure rate at 25 μg/ml, as compared to 54.42% by the untreated control) with very negligible toxicity effect on the cell viability of the normal keratinocyte cells. It also demonstrated promising antioxidant properties with 65.00%, 69.23%, and 63.03% activity at 100 μg/ml concentration for ABTS (2, 2-azinobis) (3-ethylbenzothiazoline-6-sulfonic acid)), DPPH (1, 1 diphenyl-2-picrylhydrazyl) and SOD (superoxide dismutase enzyme) assays respectively, antidiabetic potential (with a significantly high α-glucosidase inhibition potential of 99.69% at 10μg/ml concentration and 62.11% of α-amylase enzyme inhibition at 100 μg/ml concentration) and moderate tyrosinase inhibitory potential (with 17.09% at 100 μg/ml concentration). Besides, it displayed reasonable antibacterial potential with the diameter of zone of inhibition ranging between 10.89 and 12.39 mm. Further, its antibacterial mode of action reveals that its effects could be due to being very smaller, the NPs could have penetrated inside the cellular membrane thereby causing rupture and damage to the interior materials leading to cellular lysis. The photocatalytic evaluation showed that synthesized BM-GS NPs have the efficiency of degrading methylene blue dye by 34.70% within 3 h of treatment. The above findings revealed the multi-therapeutic efficacy of the sericin globular protein-mediated BM-GS NPs and its potential future applications in the cosmetics and food sector and environmental contamination management industries.

Identification of novel α-glucosidase inhibitory peptides in rice wine and their antioxidant activities using in silico and in vitro analyses

Many peptides are contained in rice wine, which may have various bioactivities, and need to be investigated. The aim of this study was to identify novel peptides with high α-glucosidase inhibition and antioxidant activities in rice wine and to illustrate their underlying mechanisms. Peptide composition, α-glucosidase inhibition and antioxidant activities of the different elution fractions from macroporous resin adsorption chromatography were investigated. Potentially bioactive peptides were screened via in silico analyses and validated by in vitro experiments, and then, their mechanisms were further investigated by molecular docking and molecular dynamics simulations. Results showed that the peptides from 50% ethanol-eluted rice wine (50%-RP) exhibited strong α-glucosidase inhibition and antioxidant activities. Three novel peptides, SSLFR, QFTPR and FTYPR screened out by in silico analyses, were confirmed to have good α-glucosidase inhibition and antioxidant activities, and FTYPR exhibited the best bioactivities. These peptides could bind to ABTS and DPPH radicals and the active site of α-glucosidase through hydrogen bonding, Pi bonding and van der Waals forces. This study may not only provide new knowledge for the health effects of rice wine, but also supply theoretical bases for the development of health products of rice wine to improve its economic value.

Functional and sensory properties of Indonesian bay leaf (Syzygium polyanthum) herbal tea

Indonesian bay leaf (Syzygium polyanthum) has been reported to contain antioxidants and antidiabetic agents that can bring many health benefits. To increase its consumption, it can be processed into herbal tea with a simple processing method. The objective of this research was to determine the effect of drying temperature, brewing temperature, and brewing time on functional properties and sensory acceptance of Indonesian bay leaf herbal tea. Indonesian bay leaf was dried at three different temperatures (40, 50 and 60oC) for 24 hrs to increase its shelf life. A drying temperature of 40oC was selected for its highest antioxidant properties among the dried Indonesian bay leaf. Indonesian bay leaf herbal tea was prepared with different brewing temperatures (80, 90 and 100oC) and brewing times (10, 20 and 30 mins). Results showed that lower brewing temperature (80oC) and longer brewing time (30 mins) could increase its functional properties, with the highest antioxidant activity (IC50) of 984.07±28.92 ppm. Indonesian bay leaf herbal tea brewed for 30 mins showed the highest α-glucosidase inhibition activity of 4704.79±26.31 ppm, about 85 times weaker compared to acarbose. However, brewing time and temperature did not affect the sensory acceptance of bay leaf herbal tea with an overall hedonic score ranging from 4-5 (slightly like).

Effects of different drying methods on phenolic components and in vitro hypoglycemic activities of pulp extracts from two Chinese bayberry (Myrica rubra Sieb. et Zucc.) cultivars

The effects of two different drying methods, namely hot-air drying and freeze drying, on the phenolic profiles, antioxidant and hypoglycemic activities of pulp extracts from two main Chinese bayberry cultivars (‘Biqi’ or ‘BQ’ and ‘Dongkui’ or ‘DK’) were evaluated. The results showed that ‘BQ’ bayberry provided higher total phenolic (TPC), total flavonoid (TFC) and total anthocyanin (TAC) contents than ‘DK’ bayberry after the same drying method, while its antioxidant and hypoglycemic activities were highly affected by drying method. Freeze-dried samples possessed significantly higher TPC, TFC and TAC, and exhibited more potent antioxidant and hypoglycemic activities than hot-air dried ones (P<0.05). Freeze-dried ‘DK’ bayberry exhibited similar antioxidant activities and α-amylase inhibitory activity, but higher α-glucosidase inhibition than freeze-dried ‘BQ’ bayberry (P<0.05). Compared with hot-air dried samples, freeze-dried samples had significantly higher contents of cyanidin-3-O-glucoside, myricitin-3-O-rhamnoside, quercetin-3-O-galactoside, quercetin-3-O-glucoside and quercetin-3-O-rhamnoside, which had been proved to be the main contributors to the in vitro hypoglycemic activities of bayberry pulp extract. All these results demonstrate that freeze drying is more suitable for the preservation of phenolic components in the pulp extract of Chinese bayberry, and the pulp extract of freeze-dried ‘DK’ could be applied as a potential hypoglycemic food additive.

Combination of Phyllanthus amarus Schum. &amp; Thonn. and Gymnema sylvestre R. Br. for treatment of diabetes and its long-term complications

Objectives. The amount of patients with diabetes is increasing, and such patients experience several long-term complications. Therefore, finding a method to treat the disease and its complications is an urgent issue worldwide. In Vietnam, Phyllanthus amarus Schum. &amp; Thonn. (PA) and Gymnema sylvestre R. Br. (GS) are common herbs used in traditional therapy including diabetes treatment. This study aimed to combine PA and GS to extend their bioactivities in antidiabetes, antioxidant, and anti-inflammatory treatments.Methods. Here, PA and GS powders were mixed at different ratios for extraction. Ethanolic extract was used to detect bioactive compounds, bioactivities, and appropriate ratios of the mixtures.Results. The optimal ratio for the PA and GS combination was 2 : 1 (g/g). The ethanolic extraction of the 2 : 1 sample at 50°C over two hours with a solid/liquid ratio of 1 : 10 achieved a high yield of 14.37%. This sample exhibited good α-glucosidase inhibition activity with a half-maximal inhibitory concentration (IC50) of 9.74 µg/mL, antioxidant activity with an IC50 of 29.87 µg/mL, and anti-inflammatory activity with an IC15 of 400 µg/mL.Conclusions. The study confirmed that combining PA and GS can have high α-glucosidase inhibition as well as antioxidant and anti-inflammatory effects.

Examination the antioxidant potentials and antidiabetic properties of phenolic extracts of some Iranian honeys

Introduction: In most ancient cultures, honey has been used for both nutritional and medical purposes. Objectives: In this research, phenolic extracts of four Iranian honeys were evaluated to determine the antioxidant potentials using DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging, nitric oxide (NO) radical scavenging and reducing power by ferric reducing activity of plasma (FRAP) method. Additionally, anti-diabetic properties of honey and phenolic extracts were evaluated by determination of α-amylase and α-glucosidase inhibition. Patients and Methods: Besides, reducing potential was evaluated by ferric-reducing antioxidant power method. Moreover, determination of phenolic and flavonoid contents was performed. Moreover, inhibition of α-amylase and α-glucosidase of honey and phenolic extracts were evaluated. Results: With considering to antioxidant potentials, Gavan (Astragalus) sample showed the greatest phenolic (3817±1.52 mg GAE/100 g), flavonoid contents (3.1±0.005 mg QE/100 g), and DPPH radical scavenging (IC50 = 2±0.003 mg/mL). Bahareh honey had the highest NO radical scavenging (IC50=0.0403±0.0009 mg/mL) and Meymand honey possessed the highest reducing potential by FRAP method (IC50=0.0018±0.000003 mg/mL). The maximum inhibition of α-glucosidase was shown in Meymand honey extract (46±0.1%). After sugar isolation, Zataria honey had the highest inhibition of α-glucosidase (54±0.6%) and the mode of α-amylase inhibition was noncompetitive by this honey. Whole extract (23±0.1%) and phenolic extract of Gavan honey presented the maximum inhibition of α-amylase (31.2±0.1%). Conclusion: Honey samples showed antioxidant potentials and anti-diabetic properties by retardation of α-amylase and α-glucosidase.

Quinazolinone-dihydropyrano[3,2-b]pyran hybrids as new α-glucosidase inhibitors: Design, synthesis, enzymatic inhibition, docking study and prediction of pharmacokinetic

A series of new quinazolinone-dihydropyrano[3,2-b]pyran derivatives 10A-L were synthesized by simple chemical reactions and were investigated for inhibitory activities against α-glucosidase and α-amylase. New synthesized compounds showed high α-glucosidase inhibition effects in comparison to the standard drug acarbose and were inactive against α-amylase. Among them, the most potent compound was compound 10L (IC50 value = 40.1 ± 0.6 µM) with inhibitory activity around 18.75-fold more than acarboase (IC50 value = 750.0 ± 12.5 µM). This compound was a competitive inhibitor into α-glucosidase. Our obtained experimental results were confirmed by docking studies. Furthermore, the cytotoxicity of the most potent compounds 10L, 10G, and 10N against normal fibroblast cells and in silico druglikeness, ADME, and toxicity prediction of these compounds were also evaluated.

Gas Chromatography-Mass Spectrometry Coupled with Multivariate Statistical Analysis to Identify the Alpha Glucosidase Inhibitors from Flesh of Salacca zalacca Fruits and Their Molecular Docking Studies

Fruit of salak (Salaaca zalacca) is traditionally used and commercialized as an antidiabetic agent. However, scientific evidence to prove this folk claim is quite lacking. Therefore, this research was aimed to evaluate the α-glucosidase inhibition activity of S. zalacca fruit and identify the bioactive compounds. The fruits were extracted by different ratios of ethanol and water (0, 20, 40, 60, 80, 100%, v/v) to get E0 (100% water), E20 (20% ethanol), E40 (40% ethanol), E60 (60% ethanol), E80 (80% ethanol), and E100 (100% ethanol) extracts. The extracts obtained were subjected to the α-glucosidase inhibitory assay. Gas chromatography-mass spectrometry- (GC-MS-) based metabolomics approach was used in profiling the bioactive metabolites present in the extracts. Orthogonal partial least square (OPLS) was used to correlate GC-MS data and α-glucosidase assay results to identify the possible chemical markers. All active compounds identified were subjected to molecular docking. The extracts from the S. zalacca fruit showed potent inhibition activity against α-glucosidase. The IC50 values from the α-glucosidase inhibitory assay ranged between 16 and 275 µg/ml. Overall, E60 displayed significantly higher α-glucosidase inhibition activity, while E0 showed the lowest α-glucosidase inhibition activity. Major compounds detected in S. zalacca fruits were sugars, fatty acids, and sterols, including myo-inositol, palmitic acid, stearic acid, and β-sitosterol. Moreover, the results obtained from molecular docking indicated that palmitic acid and β-sitosterol were close to the active side of the enzyme. Some of the residues that interacted include HID295, ASN259, LEU313, LYS125, PHE159, VAL216, PHE178, TYR72, TYR158, HIE315, ARG315, and PHE303. The bioassay result strongly suggests that E60 extract from S. zalacca fruits has potential α-glucosidase inhibitory activity. The hydrophobic compounds, including palmitic acid and β-sitosterol, were found to induce the α-glucosidase inhibition activity.

Preparation of a functional beverage with α-glucosidase inhibitory peptides obtained from ginkgo seeds.

To obtain α-glucosidase inhibitory peptides from ginkgo seeds and use it to develop beverages, papain hydrolysis was used to hydrolyze and extract ginkgo seed peptides. Through ultrafiltration and semi-preparative high performance liquid chromatography, peptide fragments which were molecular weight of < 10KDa with high α-glucosidase inhibition rate were separated and purified to prepare beverages. At the same time, the A1, A2, B1, and B2 peptide fragments purified by semi-preparative high performance liquid chromatography were analyzed for amino acid composition. All four peptide fragments have glutamate. Studies have shown that amino acids such as glutamate can promote postprandial insulin secretion and reduce glucose levels. The result indicates that the amino acid composition may be related to the inhibition rate of α-glucosidase. After orthogonal experiment design, analysis of variance and principal component analysis, when 5% xylitol and 0.3% citric acid were added, and the glycine content was 1.2%, the ginkgo polypeptides beverage had the best flavor.

Identification of bioactive compounds from Rhaponticoides iconiensis extracts and their bioactivities: An endemic plant to Turkey flora

Rhaponticoides iconiensis (Hub.-Mor.) M.V.Agab. & Greuter. (Asteraceae) is an endemic species spread in several small populations in the province of Konya (Turkey). It is critically endangered with an extremely high risk of extinction. Recently, based on the molecular phylogenetic and eco geographical studies on Cardueae-Centaureinae, the genus Rhaponticoides Vaill. was separated from Centaurea L. Antioxidant properties and enzyme inhibition, as well as the phenolic and flavonoid contents, of the methanol (Soxhlet extraction and maceration) and water (infusion) extracts of R. iconiensis leaves, roots, and flower heads were determined. The methanol extracts of R. iconiensis leaves contained the highest amount of phenolic (52.37 and 54.37 mg gallic acid equivalent/g) and flavonoids (74.13 and 80.75 mg rutin equivalent/g). Accordingly, the leaves methanol extracts showed the highest antioxidant potential. Interestingly, the roots methanol extracts were the most potent acetylcholinesterase (4.75 mg galantamine equivalent/g) and butyrylcholinesterase inhibitors (5.26 and 5.14 mg galantamine equivalent/g). The leaves and roots methanol extracts exhibited high α-glucosidase (2.48–3.08 mmol acarbose equivalent/g) and α-amylase (0.17−0.70 mmol acarbose equivalent/g) inhibition. The highest tyrosinase inhibition was recorded for leaves methanol extracts (138.79 and 140.34 mg kojic acid equivalent/g). 87 natural products (including hydroxybenzoic, hydroxycinnamic and acylquinic acids, flavones, flavonols, flavanones and anthocyanins) were unambiguously identified or tentatively annotated in the studied extracts. Findings presented in the present study appraise the bioactivity of R. iconiensis, an understudied species.

In vitro Study of Antidiabetic Effect of Abrus precatorius Methanol Leaves Extract against Glucose Absorption

Diabetes mellitus is a common chronic systemic disorder characterised by hyperglycaemia as a standard feature. A traditional plant known as Abrus precatorius (AP) has been used for the treatment of type II diabetes mellitus in Malaysia. The potential of the 80% methanolic extract of A. precatorius leaves has been tested in vitro for its α-glucosidase inhibition and its glucose diffusion activity. It was observed that the extraction of A. precatorius leaves exhibit a high α-glucosidase inhibition at the concentrations of 25 and 50 mg/mL (65.4% and 84.6%), respectively, but low inhibition at the concentration of 6.25 to 12.5 mg/mL (25% and 28.2%) when compared to control. Meanwhile, the methanolic extract of A. precatorius slightly affected the glucose diffusion at the concentration of 50 mg/mL (9.5%) within 24 h compared to the control group. These results indicated that the methanolic extract of A. precatorius leaves is capable of inhibiting α-glucosidase activity, besides halting glucose diffusion activity by delaying the glucose absorption in the gut.

Identification and Characterization of a-Glucosidase Inhibition Flavonol Glycosides from Jack Bean (Canavalia ensiformis (L.) DC.

Although the intake of jack bean (Canavalia ensiformis (L.) DC.), an underutilized tropical legume, can potentially decrease the risk of several chronic diseases, not much effort has been directed at profiling the polyphenolics contained therein. Hence, this work aimed to identify and quantify the dominant jack bean polyphenolics, which are believed to have antioxidant and other bioactivities. Four major compounds were detected and identified as kaempferol glycosides with three or four glycoside units. Their structures were established based on UV-visible, 1D, 2D NMR, and HR-ESI-MS analyses. Specifically, kaempferol 3-O-α-l-rhamnopyranosyl (1→6)- β-d-glucopyranosyl (1→2)-β-d-galactopyranosyl-7-O-[3-O-o-anisoyl]-α-l-rhamnopyranoside was detected for the first time, while the other three compounds have already been described in plants other than jack bean. This new compound was found to have a higher α-glucosidase inhibition activity compared to acarbose.

A comparative assessment of biological activities of Gundelia dersim Miller and Gundelia glabra Vitek, Yüce & Ergin extracts and their chemical characterization via HPLC-ESI-TOF-MS

Plants from the Gundelia genus have been well appraised as both food and remedies. The members of the Gundelia genus are widely used as foods in several countries including Turkey. This study presents a comparative assessment of two poorly studied Gundelia species (G. glabra Miller and G. dersim Vitek, Yüce & Ergin). The effect of conventional (infusion, maceration, and Soxhlet extraction) and non-conventional (homogeniser and ultrasound assisted extraction) methods of extraction of bioactive secondary metabolites from the selected Gundelia species was also assessed. A total of 68 different compounds were detected by high-performance liquid chromatography coupled to electrospray ionization and time-of-flight mass spectrometry (HPLC-ESI-TOF-MS) technique. Non-conventional extraction techniques do not guarantee higher antioxidant activity. As such, G. dersim (91.27, 138.87, 182.28, and 125.65 mg TE [Trolox equivalent]/g dried extract, for 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), cupric reducing antioxidant capacity (CUPRAC), and ferric reducing antioxidant power (FRAP) assays, respectively).The highest α-glucosidase inhibition was recorded for the extracts obtained by ultrasonication. In the multivariate analysis, the extracts from Gundelia species were separated based on their biological activities. The presented findings could be one methodological starting point for designing novel products from two Gundelia species.

In vitro enzyme inhibitory and anti-oxidant properties, cytotoxicity and chemical composition of the halophyte Malcolmia littorea (L.) R.Br. (Brassicaceae)

This work reports for the first time the in vitro anti-oxidant (towards DPPH, ABTS, copper and iron), enzymatic inhibitory (on AChE, BuChE, α-glucosidase, α-amylase and tyrosinase), cytotoxicity (towards HepG2 and HEK 293 cells), and metabolomics (by HPLC-MS) of extracts from organs of Malcolmia littorea (L.) R.Br. Extracts were constituted mainly by phenolic acids and flavonoids, and main compounds were salicylic acid and luteolin-7-O-glucoside. Samples showed reduced radical scavenging and metal chelating capacity, and only the methanol extracts reduced iron. The root’s ethanol and methanol extracts, and the aerial organ’s ethanol extract exhibited the highest AChE inhibition. The root’s ethanol extract displayed dual anti-cholinesterase activity. Samples showed a low capacity to inhibit α-amylase, but a high α-glucosidase inhibition was obtained with the root’s and flower’s ethanol extracts, and flower’s methanol extract. Overall, samples displayed a high inhibition against tyrosinase, reduced HepG2 cellular viability and were less toxic towards HEK 293 cells.

Biological investigations on therapeutic effect of chitosan encapsulated nano resveratrol against gestational diabetes mellitus rats induced by streptozotocin

The chitosan encapsulation with bioactive compounds (resveratrol) is a significant method that can be used to raise the stability and effectiveness of substances in gestational diabetes management. In this study, the resveratrol–zinc oxide complex is encapsulated with chitosan (CS–ZnO–RS). The synthesized CS–ZnO–RS could be used to deliver the resveratrol with minimized side effects and also improved bioavailability. CS–ZnO–RS were characterized by various techniques such as particle size analyzer, DSC, FT-IR, TEM, SEM, and AFM. The electron microscopic and particle analyzer confirmed that the synthesized CS–ZnO–RS were monodispersed, spherical and its average size was 38 nm. The drug-releasing profile showed that 95% of RS is released from CS–ZnO–RS within 24 h. In vitro studies confirmed that α-glucosidase and α-amylase inhibitory activities were closely related to the concentration of CS–ZnO–RS. The highest inhibition of α-glucosidase (77.32%) and α-amylase (78.4%) was observed at 500 μg/mL. Furthermore, the treatment of CS–ZnO–RS significantly decreased the blood glucose levels in gestational diabetes mellitus induced rats and maintained the lipid content toward the normal rats. In addition, the CS–ZnO–RS reduced the level of inflammation factors (IL-6 and MCP-1) and endoplasmic reticulum stress (GRP78, p-IRE1α, p-eIF2α, and p-PERK).

Macroalgae of Izmir Gulf: Cystoseira barbata, Cystoseira compressa and Cystoseira crinita species have high α-glucosidase and Moderate Pancreatic Lipase Inhibition Activities.

Hyperglycemia and hyperlipidemia have been symptoms of many serious diseases such as diabetes and atherosclerosis overall the world. Thus, drug researchers have focused on new, natural and healthy drug alternatives. Marine macroalgae is a great source of hypoglycemic, hypolipidemic or hypocholesterolemic agents. In this study, we investigated that hypoglycemic, hypolipidemic and cytotoxic potentials of 22 marine macroalgae from the Gulf of Izmir. According to our results, the cold methanol extract of Polysiphonia denudata exhibited the highest antioxidant activity (93.6%) compared to BHA (95.3%). Three Cystoseira species, Cystoseria crinita (91.9%), Cystoseria barbata (90.7%), Cystoseria compressa (89.8%) showed higher α-glucosidase inhibition rates than oral antidiabetic acarbose (79.5%). It has also been observed that same species are potent inhibitors of pancreatic lipase. Cytotoxicity test revealed that these extracts did not cause viability inhibition on MCF-7. The results of maltose- glucose assay indirectly displayed that Cystoseira cold methanolic extracts inhibited maltose consumption better than acarbose on HT29. The results of this screening study show that these Cystoseira species may provide non- toxic bioactive agents to control non-communicable diseases (NCDs) such as cardiovascular disease and diabetes mellitus.