In Vitro Antioxidant Properties, Glucose-Diffusion Effects, α-Amylase Inhibitory Activity, and Antidiabetogenic Effects of C. Europaea Extracts in Experimental Animals

Caralluma europaea (Guss.) N.E.Br. (C. europaea), is a medicinal plant used traditionally to treat diabetes mellitus (DM) in Morocco. This study aimed to investigate the in vitro antioxidant properties, glucose diffusion effects, α-amylase inhibitory activity, and pancreatic protective effects of C. europaea in experimental alloxan-induced diabetes in mice. Total phenolic contents were determined by Folin–Ciocalteu colorimetric method, total flavonoid contents were measured by aluminum chloride colorimetric assay, and tannins contents were determined by employing the vanillin method. C. europaea ethyl acetate fraction exhibited high antioxidant potential in terms of radical scavenging (DPPH) (IC50 = 0.22 ± 0.01 mg/mL), β-carotene bleaching activity (IC50 = 1.153 ± 0.07 mg/mL), and Ferric-reducing antioxidant power. Glucose diffusion was significantly inhibited by the ethyl acetate fraction at 60,120and 180 min, while the aqueous extract did not have this inhibitory effect when compared with the control group. Potent α-amylase inhibitory activity was observed in the ethyl acetate fraction and the aqueous extract in vitro and in vivo using STZ-diabetic rats. On the other hand, the administration of the ethyl acetate fraction (60 mg/kg) significantly attenuated alloxan-induced death and hyperglycemia in treated mice. Furthermore, histopathological investigations revealed that the ethyl acetate fraction protected islets of Langerhans against alloxan-induced tissue alterations. These results suggest that C. europaea exhibited an important antihyperglycemic effect via the inhibition of glucose diffusion and pancreatic α-amylase activity. In addition, the antidiabetogenic effect of C. europaea might be attributed to their polyphenol and flavonoid compounds, which could be reacted alone, or in synergy, to scavenge the free radicals produced by the alloxan.

Phytochemical analysis and In vitro Antidiabetic activity of aqueous extract of Lagerstroemia speciosa and Aegle marmelos

Diabetes Mellitus is a metabolic disorder characterized by hypoglycemia, resulting from absolute or relative deficiency of insulin. Worldwide about 220million people affected. Low-cost herbal treatment is recommended due to their lesser side effect. The aim of the current study was to determine the antidiabetic activity of aqueous leaf extracts of Lagerstroemia speciosa (Lythraceae) and Aegle marmelos (Rutaceae) using alpha amylase inhibition assay and glucose diffusion inhibition assay. In alpha amylase inhibition assay, the leaf extracts of A.marmelos (at a concentration 100µg/ml) exhibited 54.68% of α amylase inhibitory activity with an IC 50 values 92.04µg/ml whereas the leaf extracts of L. speciosa (at a concentration of 100µg/ml) exhibited 60.36% of α amylase inhibitory activity with an IC50 value of 68.19µg/ml .However the mixture of plant extracts (at a concentration of 100µg/ml) exhibited 94.87% inhibition with an IC50 value of 13.145µg/ml. Both plant extracts showed appreciable α amylase inhibitory effects, but the mixture showed more inhibitory effects than the individual plant extracts. In glucose diffusion inhibition assay, the aqueous extract of A. marmelos leaves exhibited maximum glucose diffusion inhibition (76.886%) at 150 minutes as well as L. Speciosa leaf extract showed the maximum inhibition of 79.5357% at the same time interval. The mixture of plant extracts exhibited 87.4274% inhibition at 150 minutes which produces more effects than the two plants.

Effect of Physicochemical Properties of Carboxymethyl Cellulose on Diffusion of Glucose

Soluble dietary fibers (SDF) are known to reduce the post-prandial plasma glucose levels. However, the detailed mechanisms of this reduced glucose release in the human gut still remain unclear. The aim of our study was to systematically investigate the effect of different types of SDF on glucose release in an in vitro model as a prerequisite for the selection of fibers suitable for application in humans. Three types of carboxymethyl cellulose (CMC) were used to investigate the correlations between fiber concentration, molecular weight (MW), and viscosity on diffusion of glucose using a side-by-side system. CMC solutions below the coil overlap (c*) influenced the glucose diffusivity only marginally, whereas at concentrations above c* the diffusion of glucose was significantly decreased. Solutions of lower MW exhibited a lower viscosity with lower glucose diffusion compared to solutions with higher MW CMC, attributed to the higher density of the solutions. All CMC solutions showed a systematic positive deviation from Stokes-Einstein behavior indicating a greater rise in viscosity than reduction in diffusion. Therefore, our results pave the way for a new approach for assessing glucose diffusion in solutions comprising dietary fibers and may contribute to further elucidating the mechanisms of post-prandial plasma glucose level reduction.

Anti-hyperglycaemic and insulin releasing effects of Camellia sinensis leaves and isolation and characterization of active compounds

Antidiabetic actions of Camellia sinensis leaves, used traditionally for type 2 diabetes (T2DM) treatment, have been determined. Insulin release, membrane potential and intracellular calcium ([Ca2+]i) were studied using the pancreatic beta-cell line, BRIN-BD11, and primary mouse pancreatic islets. Cellular glucose-uptake/insulin action by 3T3-L1 adipocytes, starch digestion, glucose diffusion, DPP-IV activity and glycation were determined together with in vivo studies assessing glucose homeostasis in high fat fed (HFF) rats. Active phytoconstituents with insulinotropic activity were isolated using RP-HPLC, LCMS and NMR. Hot water extract of Camellia sinensis, increased insulin secretion in concentration dependent manner. Insulinotropic effects were significantly reduced by diazoxide, verapamil and under calcium-free conditions, being associated with membrane depolarization and increased intracellular Ca2+. Insulin releasing effects were observed in presence of KCl, tolbutamide and IBMX, indicating actions beyond K+ and Ca2+channels. Extract also increased glucose uptake/insulin action in 3T3L1 adipocyte cells and inhibited protein glycation, DPP-IV enzyme activity, starch digestion and glucose diffusion. Oral administration of extract enhanced glucose tolerance and insulin release in HFF rats. Extended treatment (250mg/5ml/kg orally) for 9 days, led to improvements of body weight, energy intake, plasma and pancreatic insulin, and corrections of both islet size and β-cell mass. These effects were accompanied by lower glycaemia and significant reduction of plasma DPP-IV activity. Compounds isolated by HPLC/LCMS, isoquercitrin and rutin (464.2 Da & 610.3 Da), stimulated insulin release and improved glucose tolerance. These data indicate that Camellia sinensis leaves warrant further evaluation as an effective adjunctive therapy for T2DM and source of bioactive compounds.

Antioxidant and antidiabetic properties of isolated fractions from methanolic extract derived from the whole plant of Cleome viscosa L.

Background Cleome viscosa is considered as an important medicinal plant extensively used in India, China, Bangladesh, and a few countries in Africa. In the present study, in vitro anti-radical and antidiabetic potential of isolated fractions of methanolic extract of C. viscosa whole plant (MeCV) has been investigated. The identification of polyphenols and their related functional groups in the bioactive fraction was categorized by using HPLC and FT-IR. Results The total phenolic and flavonoid contents of F-D were higher than those of F-A, F-B, and F-C. The F-D exhibited superior antioxidant capacity when compared with the remaining three fractions. However, the F-D showed the highest glucose diffusion activity over the 30 min–27 h incubation period and also inhibited both α-glucosidase and α-amylase enzyme activity. HPLC analysis revealed the presence of the two known compounds (protocatechuic acid hexoside, rutin) and six unknown compounds in the F-D. FTIR spectrum confirmed the presence of phenol group. Conclusion The isolated F-D obtained from MeCV displayed superior antioxidant and antidiabetic activity which indicate the presence of polyphenols in the fraction. The data findings of the present study support the traditional uses of the whole plant of C. viscosa as a promising natural source of biological medicines for oxidative stress and diabetes.

Assessment of the Nutritional Value, Techno-Functional, and In Vitro Physiological Properties of Six Edible Insects

The objective of this study was to evaluate the nutritional composition, techno-functional, and in vitro physiological properties of flours from six different insect species (mealworm, beetle, caterpillar, ant, locust, and cricket). The chemical composition of insects was evaluated following the standard methods (AOAC). Bulk density, water holding capacity, oil holding capacity, water absorption capacity, swelling capacity, emulsifying activity, foaming capacity, and gelation capacity were measured. In vitro antioxidant capacity was measured by the direct ABTS method. Hypoglycemic (glucose adsorption and the inhibition of α-amylase, glucose diffusion, and starch hydrolysis) and hypolipidemic (cholesterol and bile salts binding and lipase inhibition capacities) were investigated using in vitro methods. Insect flours exhibited a high content of protein (39.4%–58.1%) and fat (17.7%–50.1%) as main components, although the presence of chitin in ant samples was also highlighted. The techno-functional properties showed high oil holding, swelling, and emulsifying capacities in all insect flours analyzed, besides bulk density, hydration properties, and foaming capacity showing average values and no gelation capacity. Insects showed high antioxidant capacity (179–221 mg Trolox equivalents/g). Moreover, these edible insect flours revealed effective hyperglycemic and hyperlipidemic properties. Insect flours inhibited α-amylase activity (47.1%–98.0%) and retarded glucose diffusion (17.2%–29.6%) and starch hydrolysis (18.2%–88.1%). Likewise, they bound cholesterol and bile salts (8.4%–98.6%) and inhibited lipase activity (8.9%–47.1%). Hence, these insect flours might be of great interest to the food industry, being a healthy source of protein, exerting a positive impact on functional food properties, and potentially preventing the development of diseases associated with hyperglycemia and hyperlipidemia.

Development of an Organ-on-a-Chip-Device for Study of Placental Pathologies

The human placenta plays a key role in reproduction and serves as a major interface for maternofetal exchange of nutrients. Study of human placenta pathology presents a great experimental challenge because it is not easily accessible. In this paper, a 3D placenta-on-a-chip model is developed by bioengineering techniques to simulate the placental interface between maternal and fetal blood in vitro. In this model, trophoblasts cells and human umbilical vein endothelial cells are cultured on the opposite sides of a porous polycarbonate membrane, which is sandwiched between two microfluidic channels. Glucose diffusion across this barrier is analyzed under shear flow conditions. Meanwhile, a numerical model of the 3D placenta-on-a-chip model is developed. Numerical results of concentration distributions and the convection–diffusion mass transport is compared to the results obtained from the experiments for validation. Finally, effects of flow rate and membrane porosity on glucose diffusion across the placental barrier are studied using the validated numerical model. The placental model developed here provides a potentially helpful tool to study a variety of other processes at the maternal–fetal interface, for example, effects of drugs or infections like malaria on transport of various substances across the placental barrier.