Alginate extraction is from seaweed, and lignin separation is from by-product corn (stalks and leaves). Alginate/lignin is a synthetic polymer rich in biological activity of great interest. Antioxidant activities of alginate/lignin were evaluated, such as total antioxidant activity, reducing power activity, DPPH free radical scavenging activity, and α – glucosidase inhibition activity. The test of anticancer activity was on four cell lines (Hep G2, fibroblast, MCF-7, and NCI H460). Determination of physical-chemistry characteristics of alginate/lignin was through FTIR, DSC, SEM_EDS, SEM_EDS mapping, XRD, XRF, and 1H-NMR. A study of acute toxicity of alginate/lignin was on Swiss albino mice. The results showed alginate/lignin possessed antioxidant activity such as total antioxidant activity, reducing power activity, especially, α – glucosidase inhibition activity, and no free radical scavenging activity. Alginate/lignin did not be typical in cancer cell lines. Alginate/lignin existed in a thermally stable regular spherical shape in the investigated thermal region. Some specific functional groups of alginate and lignin did not exist in alginate/lignin crystal. Elements such as C, O, Na, and S were popular in the alginate/lignin structure. LD0 and LD100 of alginate/lignin in mice were 3.91 g/kg and 9.77 g/kg, respectively. Alginate/lignin is the potential for application as pharmaceutical materials, functional foods, and supporting diabetes treatment.

The inhibition of alpha-glucosidase and alpha-amylase is one of clinic strategies for remedy the type II diabetes. Herbal medicines are reported to alleviate hyperglycemia. However, the constituents from those sources whether are targeted to the alpha-glucosidase and alpha-amylase still unexplored. This study attempted to select the compounds for efficacy of hypoglycemia via cellular and mouse levels. The results illustrated that the cytotoxicity in all tested compounds at various concentrations except the concentration of 16-hydroxy-cleroda-3,13-dine-16,15-olide (HCD) at 30 µM were not significant difference (p > 0.05) when compared with the untreated control. Acarbose (reference drug), Antroquinonol, Catechin, Quercetin, Actinodaphnine, Curcumin, HCD, Docosanol, Tetracosanol, Berberine, and Rutin could effectively inhibit the alpha-glucosidase activity of Caco-2 cells when compared with the control (maltose). The compounds (Curcumin, HCD, Tetracosanol, Antroquinonol, Berberine, Catechin, Actinodaphnine, and Rutin) could reduce blood sugar level at 30 min in tested mice. The effects of tested compounds on area under curve (AUC) were significant (p < 0.05) among Acarbose, Tetracosanol, Antroquinonol, Catechin, Actinodaphnine, and Rutin along with Berberine and Quercetin. In in vitro (alpha-glucosidase) with in vivo (alpha-amylase) experiments suggest that bioactive compounds can be a potential inhibitor candidate of alpha-glucosidase and alpha-amylase for the alleviation of type II diabetes.

Research has shown that the consumption of herbal teas is linked with positive effects on the regulation of postprandial blood glucose level. In this study, a comparative analysis of aqueous and ethanol extractions is performed on four herbal teas (Mallotus, Cyclocarya, Rubus, Vine) to evaluate their phytochemical profiles and functional activities. Investigations of phytochemical contents, antioxidant activities, α-glucosidase inhibitory activities and chemical compositions are carried out through colorimetric analyses and UPLC-Q-Orbitrap HRMS/MS, respectively. Results showed that among the studied herbal teas, Vine exhibited the highest glucose re-gulating abilities under both aqueous and ethanol extractions. Overall, ethanol extracted samples yielded higher phytochemicals content, but the compositions of the phytochemicals varied. Meanwhile, aqueous extracts showed surprisingly strong antioxidant activities and comparable α-glucosidase inhibitory activities with ethanol extracts. Phytochemicals contents presented a positive correlation with antioxidant activities and α-glucosidase inhibitory activities. Nevertheless, antioxidant activities displayed a weak positive correlation with α-glucosidase inhibitory activities. Results from this study provided evidence that aqueous extracts from herbal teas possessed valuable phytochemicals composition for antioxidants and the hyperglycemic populations, and are promising candidates for potential applications as functional ingredients with health promoting effects and as natural additives to boost the nutritional value of herbal food products.

The α-glucosidase inhibitor is of interest to researchers due to its association with type-II diabetes treatment by suppressing postprandial hyperglycemia. Hesperidin is a major flavonoid in orange fruit with diverse biological properties. This paper evaluates the effects of hesperidin on α-glucosidase through inhibitory kinetics, fluorescence quenching, and molecular docking methods for the first time. The inhibition kinetic analysis showed that hesperidin reversibly inhibited the α-glucosidase activity with an IC50 value of 18.52 M and the inhibition was performed in an uncompetitive type. Fluorescence quenching studies indicated that the intrinsic fluorescence of α-glucosidase was quenched via a static quenching process and only one binding site was present between hesperidin and α-glucosidase. The interaction between them was spontaneous and mainly driven by hydrogen bonds as well as hydrophobic forces. Furthermore, molecular docking results suggested that hesperidin might bond to the entrance or outlet part of the active site of α-glucosidase through a network of five hydrogen bonds formed between hesperidin and the four amino acid residues (Trp709, Arg422, Asn424, and Arg467) of ?-glucosidase and hydrophobic effects. These results provide new insights into the inhibitory mechanisms of hesperidin on α-glucosidase, supporting the potential application of hesperidin-rich orange product as a hypoglycemic functional food.

β-glucosidases (BGLs) play a crucial role in the degradation of lignocellulosic biomass as well as in industrial applications such as pharmaceuticals, foods, and flavors. However, the application of BGLs has been largely hindered by issues such as low enzyme activity, product inhibition, low stability, etc. Many approaches have been developed to engineer BGLs to improve these enzymatic characteristics to facilitate industrial production. In this article, we review the recent advances in BGL engineering in the field, including the efforts from our laboratory. We summarize and discuss the BGL engineering studies according to the targeted functions as well as the specific strategies used for BGL engineering.

Wendan (a type of pomelo), as a popular fruit in China, is less known in other countries. Its peel is widely used in food and traditional medicine. Four different origins of Wendan pomelo were selected, and crude extracts were obtained by the Soxhlet extraction method. The composition of Wendan peel was analyzed by high-performance liquid chromatography-mass spectrometry (HPLC-MS) in positive ion mode. The compounds were identified by searching the Metabolite Link (METLIN), Spectral Database for Organic Compounds (SDBS) and referring to literature reports. A total of 20 compounds were identified among the samples from the four origins, of which 8 compounds were common. The majority of the compounds belonged to the flavonoid and coumarin classes, Meranzin hydrate was identified for the first time in pomelo peel. In vitro antioxidant activity experiments showed that samples from Taizhou, Zhejiang exhibited the highest antioxidant activity in the DPPH, ABTS, and FRAP assays, with values of 0.59 mg/mL, 97.06 μmol TE/g, and 60.62 μmol Fe2+/g, respectively. Samples from Zhangzhou, Fujian showed antioxidant activity second only to the samples from Taizhou, Zhejiang. The sample from Zhangzhou, Fujian Province, showed excellent inhibitory activity in the α-glucosidase inhibition assay (IC50=7.99 mg/mL).

Soy isoflavones are considered important sources of bioactive compounds, but they are poorly absorbable, due to their large hydrophilic structures. Some biotransformation strategies have been used to convert the glycosidic form into aglycones, making them available for absorption. This study evaluated the potential of enzymatic and/or microbial fermentation bioprocesses in soymilk extract before and after gastrointestinal in vitro digestion. Commercial β-glucosidase and mix of commercial probiotics containing Lactobacillus acidophilus, L. casei, Lactococcus lactis, Bifidobacterium bifidum e B. lactis were used to biotransform soymilk extract. Isoflavone profile was quantified by HPLC-DAD, total phenolic content by Folin–Ciocalteu test, and antioxidant capacity by ORAC and FRAP. Soymilk enzymatically treated (ET) followed by microbial fermentation (ET+F) resulted in the conversion of glycosylated isoflavones (6-fold lower than control for daidzin and 2-fold for genistin) to aglycones (18-fold greater than control for dadzein and genistein), besides to increase the total phenolic content (3.48 for control and 4.48 mg/ml ET+F) and to improve antioxidant capacity represented by the ORAC (120 for control and 151 mg/ml ET+F) and by the FRAP (285 for control and 317 µl/ml for ET+F) before in vitro digestion. Further, the digested ET+F samples resulted a higher content of genistein (2-fold higher than control) also an increase in the total phenolic content (2.81 for control and 4.03 mg/ml for ET+F) and antioxidant capacity by ORAC were greater compared to undigested samples. In addition, the microbial fermentation process isolated also resulted in the positive effects, but de combination of ET followed by F presented a synergistic effect, suggesting the greater potential for both bioprocesses to contribute to functional and nutritional properties on fermented soy-based products.

Degradation of intracellular components through autophagy is a fundamental process to maintain cellular integrity and homeostasis. Recently a glycogen-selective autophagy pathway has been described, termed ‘glycophagy’. Glycogen is a primary storage depot and regulator of glucose availability, and glycophagy is emerging as a critical physiological process involved in energy metabolism. Glycophagy-mediated degradation of glycogen appears to operate in parallel with the well-described canonical pathway of glycogenolysis involving glycogen phosphorylase. Evidence suggests that starch-binding domain protein-1 (Stbd1) is a key glycogen-binding protein involved in tagging glycogen for glycophagy, and that Gabarapl1 is primarily involved as the Atg8 family protein recruiting the Stbd1-glycogen complex into the forming glycophagosome. The nuances of glycophagy protein machinery, regulation and lysosomal glucose release are yet to be fully elucidated. In this mini-review, we critically analyze the current evidence base for glycophagy as a selective-autophagy process of physiological importance and highlight areas where further investigation is warranted.

New class of triazinoindole bearing thiosemicarbazide (1-25) was synthesized and evaluated for α-glucosidase inhibitory potential. All synthesized analogues exhibited excellent inhibitory potential having IC50 values ranging from 1.30 ± 0.01 to 35.80 ± 0.80 µM when compared with the standard acarbose having IC50 value 38.60 ± 0.20 µM. Among series the analogues 1 and 23 was found the most potent having IC50 values 1.30 ± 0.05 and 1.30 ± 0.01 µM respectively. Structure activity relationship (SAR) was mainly based upon by bring about difference of substituents on phenyl rings. To confirm the binding interactions, molecular docking study was performed. Synthesized analogues were characterized through HREI-MS, 1H and 13C-NMR analysis.

Cordia dichotoma Forst. (F. Boraginaceae) has been traditionally used for the management of a variety of human ailments. In our earlier work, the antidiabetic activity of methanolic bark extract of C. dichotoma (MECD) has been reported. In this paper, two flavonoid molecules were isolated (by column chromatography) and identified (by IR, NMR and Mass spectroscopy/spectrometry) from the MECD with an aim to investigate their antidiabetic effectiveness. Molecular docking and ADMET studies were carried out using AutoDock Vina software and Swiss ADME online tool, respectively. The isolated flavonoids were identified as 3,5,7,3’,4’-tetrahydroxy-4-methoxyflavanone-3-O-L-rhamnopyranoside and 5,7,3’-trihydroxy-4-methoxyflavanone-7-O-L-rhamnopyranoside (quercitrin). Docking and ADMET studies revealed the promising binding affinity of flavonoid molecules for human lysosomal alpha-glucosidase and human pancreatic alpha-amylase with acceptable ADMET properties. Based on computational studies, our study reports the antidiabetic potential of the isolated flavonoids with predictive pharmacokinetics profile.

To elucidate the chemical compositions of the sugar fall maple leaves, the methanol extracts were firstly fractionated by ethyl acetate and n-butanol respectively. The phenolic acids-rich fractions (ethyl acetate extracts) were further purified by various chromatographic columns including XAD macroporous resin, Sephadex LH-20, ODS and semi-preparative HPLC to yield the compounds. The isolated compounds were characterized by ¹H-Nuclear Magnetic Resonance (¹H-NMR), ¹³C-NMR, and high resolution electrospray ionisation mass spectral (HR-ESI-MS) spectroscopy. Twenty eight phenolics including fourteen flavonoids (1-14), five quinic acid derivatives (15-19), five galloyl tannins (20-24) and four other phenolic acids (25-28) were isolated and their structures were identified. The isolated compounds were evaluated for their antioxidant and α-glucosidase inhibitory activities. All of the phenolics constituents showed DPPH scavenging antioxidant activities. While, glycosides of quercetin and myricetin, galloyl tannins were showed promising α-glucosidase inhibitory activity. All of the compounds except 4, 11, 12 and 28 were isolated from sugar maple for the first time. Moreover, Compounds 9, 10, 14, 20, 21, 23, 25 and 26 were isolated from the Acer species for the first time.

To determine the mode of action of the effects of phytoalexins in soybeans, we analyzed enzyme inhibition kinetics using Michaelis–Menten plots and the Lineweaver–Burk plots. The results showed that glyceollin showed competitive inhibition, genistein showed noncompetitive, daidzein was uncompetitive, and luteolin showed a mixed mode of action. The Ki values were determined using a Dixon plot as: glyceollin, 18.99; genistein, 15.42; luteolin, 16.81; and daidzein, 9.99 μM, respectively. Furthermore, potential synergistic effects between glyceollin and the three designated polyphenols were investigated. A combination of glyceollin and luteolin (the ratio of 3:7 of glyceollin and luteolin) had synergistic effects on α-glucosidase inhibition according to combination index (CI)-isobologram equation. Collectively, these results showed that a combination of glyceollin and luteolin has the potential to inhibit α-glucosidase activity via a synergistic mode of action.

Curcuma longa is only a rich source of curcumin (1) and its major analogues demethoxycurcumin (2) and bisdemethoxycurcumin (3) among the Curcuma species. The content ratio of these three curcumins in turmeric is depended on the varieties and growing environment. Recently, curcumin (1) has been reported as potential inhibitor of hepatic and enzymatic protein tyrosine phosphatase 1B (PTP1B) and its related disorders such as hypertriglyceridemia, hyperlipidemia and liver steatosis. Thus, we further purified curcumins (1–3) from C. longa and investigated their inhibitory effects against PTP1B and α-glucosidase enzymes. As the result, curcumins (1–3) exhibited potential PTP1B inhibition with IC50 values of 37.8 ± 1.4, 45.3 ± 0.7, and 72.6 ± 1.1 μM, respectively, and α-glucosidase inhibition with similar manner (IC50 values of 78.2 ± 0.2, 82.4 ± 0.6, and 90.6 ± 1.0 μM, respectively). These results reveal a key role of methoxylation in the variation of PTP1B and α-glucosidase inhibitory activity for these curcumins. In addition, density functional theory (DFT) was used accompanying with molecular docking (MD) to analyze the ligand stability and the interaction of curcumins (1–3) with PTP1B and glucoside hydrolase proteins. Assay-based results and the MD data obtained are highly correlation suggesting that the deterioration of the enzyme activity caused by the distortion of structural conformation of PTP1B and glucoside hydrolase may be related to the arrangement of amino acids in protein structure. This reported for the first time that inhibitory effects of curcumins (1–3) against PTP1B and glucoside hydrolase have been examined in vitro and in silico as well.

Diabetes mellitus (DM) is one of the most dangerous metabolic diseases with high rate of mortality worldwide. It is well known that insulin resistance and deficiency in insulin production from pancreatic β-cells are the main characteristic of DM. Due to the detrimental side effects of the current treatment, there is a considerable need to develop new effective antidiabetic drugs, especially alpha-glucosidase and alpha-amylase inhibitors with lesser adverse effects. These inhibitors are known to be directly involved in the delay of carbohydrate digestion, resulting in a reduction of glucose absorption rate and consequently reduce the post-prandial raise of plasma glucose, which can reduce the risk of long-term diabetes complications. Hence, natural products are well-known sources for the discovery of new scaffold for drugs discovery, including new antidiabetic drugs. The phytochemical investigation of Salvia aurita collected from Hogobach pass, Eastern Cape, South Africa (SA), yielded four known abietane diterpenes namely carnosol (1), rosmanol (2), 7-methoxyrosmanol (3), 12-methoxycarnosic acid (4) and one flavonoid named 4,7-dimethylapigenin (5). Structural characterization of these isolated compounds was conducted using 1 and 2D NMR, in comparison with reported spectroscopic data. These compounds are reported for the first time from S. aurita. The biological evaluation of the isolated compound against alpha-glucosidase exhibited strong inhibitory activities for 3 and 2 with IC50 values of 4.2 ± 0.7 and 16.4 ± 1.1 µg/mL respectively, while 4 and 1 demonstrated strong alpha-amylase inhibitory activity amongst the isolated compounds with IC50 of 16.2 ± 0.3 and 19.8 ± 1.4 µg/mL. Molecular docking analysis confirms strong inhibitory activity of 3 against alpha-glucosidase. Additionally, excellent antioxidant capacities were displayed by 2, 1 and 3 respectively as ORAC (25789.9 ± 10.5; 23961.8 ± 14.1; 23939.3 ± 2.4) µM TE/g; 1 and 2 as FRAP (3917.8 ± 2.1; 1522.3 ± 0.9) µM AAE/g; 5 and 2 as TEAC (3190.4 ± 2.8; 2055.0 ± 2.6) µM TE/g. The methanolic extract of S. aurita is a rich source of abietane diterpenes with excellent antioxidant and anti-diabetic activities that can be useful to modulate oxidative stress, and might possibly be excellent candidates for the management of diabetes. This is the first scientific report on the phytochemical isolation and biological evaluation of alpha-glucosidase and alpha-amylase inhibitory activities of Salvia aurita.

Over the last decades, the increased incidence of metabolic disorders such as type 2 diabetes and obesity has motivated researchers to investigate new enzyme inhibitors. In this study, the inhibitory effects of synthetic amino acid derivatives (PPC80, PPC82, PPC84, PPC89, and PPC101) on the activity of digestive enzymes was assessed by in vitro assays. The inhibitory effect was determined by the inhibition percentage and the 50% inhibitory concentration (IC50), and the mechanism of action was investigated by Lineweaver–Burk plots. PPC80, PPC82, and PPC84 inhibited pancreatic lipase (IC50 of 1.67–10.23 x 10-1 mmol/L). The activity of pancreatic α-amylase was suppressed by PPC80, PPC82, PPC84, PPC89, and PPC101 (IC50 of 1.62–5.19 x 10-1 mmol/L). Finally, PPC84, PPC89, and PPC101 also showed a potent inhibitory effect on α-glucosidase (IC50 of 0.51–3.53 x 10-1 mmol/L). PPC80 and PPC82 followed a non-competitive inhibition mechanism against pancreatic lipase, while PPC84 acted through competitive inhibition. The inhibition of pancreatic α-amylase by the derivatives was non-competitive, as well as for PPC84, PPC89 and PPC101 against α-glucosidase. The results suggest that these synthetic amino acid derivatives have inhibitory potential against digestive enzymes and may be used as therapeutic agents to control metabolic disorders.

Acetic acid bacteria (AAB) form a bacterial film on the surface of alcoholic solutions and ferment ethanol to acetic acid while also producing bioactive compounds. To discover functional AAB for industrial use, we isolated and selected strains from farm-produced vinegars using a CaCO3-containing medium. The seven strains belonged to Acetobacter cerevisiae and A. pasteurianus. Physiological properties were determined, including ethanol tolerance at up to 12% (v/v). Acidification at a growth temperature of 40 ℃ was seen for GHA 7, GYA 23, JGB 21-17, and GHA 20 strains, which may be useful in vinegar production where thermotolerant AAB are required. The seven AAB isolates had strong antibacterial activity against Staphylococcus aureus. Antioxidant activity was 2- and 4-fold higher, respectively, for A cerevisiae and A. pasteurianus than for the control, 1% acetic acid. We also observed 91.3% inhibition of angiotensin-converting enzyme activity for the KSO 5 strain, higher than that for the positive control, 0.1% captopril (76.9%). All strains showed complete inhibition of α-glucosidase, except JGB 21-17 and GHA 7 with 98.3% inhibition. Our work suggests usefulness of the strains selected as seed strains for highly efficient production of functional vinegar and illustrates identification of useful functional characteristics on a scientific basis.

In recent years there has been increasing interest in the discovery of new natural herbal remedies for the treatment of common conditions such as diabetes and inflammatory diseases. In this context, this paper analyzed the antidiabetic and anti-inflammatory potential of two plants of the genus Artemisia: Artemisia absinthium (wormwood) and Artemisia vulgaris (mugwort) and Trigonella foenum-graecum (fenugreek) plants less studied from this point of view. Thus, hydroal-coholic extracts (50% EtOH v/v, 10% mass) were made, which were processed by membrane technologies, micro- and ultrafiltration, in order to concentrate the biologically active principles. The extracts were then analyzed in terms of content in active principles of interest (polyphenols, flavones). The antidiabetic activity of the extracts was analyzed by testing their ability to inhibit α-amylase and α-glucosidase and the anti-inflammatory activity by testing the ability to inhibit hyaluronidase (HYA) and lipoxygenase (LOX). Thus, the T. foenum-graecum extracts showed a high inhibitory activity on α-amylase 3.22 ± 0.3 g / mL (compared to the standard used - IC50 acarbose = 3.5 g / mL) and a high inhibitory activity on LOX: 19.69 ± 0.52 g/mL (compared to all standards used). The concentrated extract of Artemisia vulgaris showed increased activity of inhibition of α-amylase - IC50 = 8.57 ± 2.31g/mL and moderate activity of inhibition of HYA - IC50 = 17.18 g/mL compared to ibuprofen, the standard used - IC50 = 5.73 g/mL. The concentrated extract of Artemisia absinthium showed a pronounced activity of inhibition of LOX - IC50 = 19.71 g / mL, compared to the standard - rutin - IC50 = 22.34 g/mL).

Plants offer a simpler and cheaper alternative to mammalian animal models for the study of Endoplasmic Reticulum glycoprotein folding Quality Control (ERQC). In particular, the Arabidopsis thaliana (At) innate immune response to bacterial peptides provides an easy means of assaying ERQC function in vivo. A number of mutants that are useful to study ERQC in planta have been described in the literature, but only for a subset of these mutants the innate immune response to bacterial elicitors has been measured beyond monitoring plant weight and some physio-pathological parameters related to the plant immune response. In order to probe deeper into the role of ERQC in the plant immune response, we monitored expression levels of the PHI-1 and RET-OX genes in the At ER α-Glu II rsw3 and the At UGGT uggt1-1 mutant plants, in response to bacterial peptides elf18 and flg22. The elf18 response was impaired in the rsw3 but not completely abrogated in the uggt1-1 mutant plants, raising the possibility that the latter enzyme is partly dispensable for ERF signalling. In the rsw3 mutant, seedling growth was impaired only by concomitant application of the At ER α-Glu II NB-DNJ inhibitor at concentrations above 500 nM, suggesting residual activity in this mutant. The study highlights the need for extending plant innate immune response studies to assays sampling EFR signalling at the molecular level.