Evaluation of antidiabetic and antioxidant effects of Polygonum cognatum Meisn. and phytochemical analysis of effective extracts

Polygonum cognatum Meisn. (Polygonaceae) is used both as food and as a folk medicine to treat diabetes. This study aimed to evaluate the effect of the extracts, along with isolated compounds, from P. cognatum aerial parts on diabetes. In vitro studies were conducted using an α-glucosidase inhibitory assay, while in vivo antidiabetic studies were carried out on streptozotocin-induced diabetic rats. Effective extracts were subjected to isolation studies, and structures of the compounds were elucidated by spectroscopic methods. The ethyl acetate and n-butanol extracts had the highest effect in both in vitro and in vivo experiments. They also decreased aspartate transaminase, alanine transaminase and malondialdehyde levels, while increasing glutathione and superoxide dismutase activity in rats. From the active extracts, 11 phenolic compounds were isolated and characterized. Among the isolated compounds, quercetin was found to be the most active according to α-glucosidase inhibitory activity studies. This study provided scientific evidence for the traditional use of P. cognatum as a folk medicine for treating diabetes. The findings suggest that the ethyl acetate and n-butanol extracts, as well as quercetin, have the potential for development as antidiabetic agents.     

Anti-Alzheimer,antidiabetic and antioxidant potential of Satureja cuneifolia and analysis of its phenolic contents by LC-MS/MS

Many chronic diseases such as diabetes and Alzheimer’s disease are related to the type and quality of foods, which are consumed. Particularly, various plant origin products are stated as beneficial against such kind of chronic diseases with secondary metabolites such as their phenolic structures. Satureja cuneifolia is a plant, which is consumed as an herbal tea in some regions of Turkey and that’s why investigate of its biological activity is important. In our study, the anti-diabetic and anti-Alzheimer potentials of the methanol and water extracts of S. cuneifolia plant were measured via some enzymes inhibition experiments as in vitro. The antioxidant ability of the same extracts was measured via radical scavenging and reducing power methods. Also, the total phenolics and flavonoids of the plant were identified. Finally, the extracts were analyzed by the LC-MS/MS analysis and the phenolic content of S. cuneifolia was clarified.     

Bioprospecting Dodonaea viscosa Jacq.; a traditional medicinal plant for antioxidant,cytotoxic, antidiabetic and antimicrobial potential

Purpose of studyDodonaea viscosa Jacq. is an ethnomedicinal plant that has been extensively used for the treatment of gout, rheumatism and pain. Current study was undertaken to mine its antioxidant, antimicrobial, cytotoxic and antidiabetic potential. Chromogenic assays were employed to establish plant’s multimode antioxidant profile whereas HPLC fingerprinting was performed to quantify polyphenols. Standard brine shrimp lethality, MTT and SRB assays proved its cytotoxicity potential.ResultsAmong all the extracts (flower, leaf, stem and root), maximum extract recovery (22% w/w), gallic acid equivalent total phenolic content (20.11 ± 0.11 ug GAE/mg DW), ascorbic acid equivalent total antioxidant capacity (22.5 ± 0.07 µg/mg DW) and total reducing power (31.1 ± 1.13 µg/mg DW) were recorded in the distilled water + acetone extract of leaf. The acetone extract of leaf showed maximum quercetin equivalent total flavonoid content (4.78 ± 0.13 µg/mg DW). HPLC-DAD analysis revealed significant amount of rutin, vanillic acid, coumaric acid, ferulic acid, gallic acid, syringic acid, cinnamic acid, gentisic acid, catechin, caffeic acid, apigenin and myricetin in the different plant parts. Maximum scavenging potential was exhibited by methanol + ethyl acetate stem extract (IC₅₀ = 23.8 µg/ml). The highest antibacterial potential was found in flower (85.7%) and root (71.4%) extracts. The ethanol + ethyl acetate (1:1) leaf extract showed noteworthy toxicity against brine shrimps (LC₅₀ = 95.46 µg/ml) while a notable antiproliferative activity against THP-1 (IC₅₀ = 3.4 µg/ml) and Hep G2 (IC₅₀ = 20 µg/ml) cell lines was shown by ethanol + ethyl acetate extracts (1:1) of stem and root, respectively. A moderate inhibition of α-amylase enzyme was observed in all parts of the plant.ConclusionThe results of the present study suggest D. viscosa as a potential source of antioxidant, anticancer and α-amylase inhibitory phytochemicals.     

Molecular docking of phenolic compounds and screening of antioxidant and antidiabetic potential of Olea europaea L. Ethanolic leaves extract

Oxidative stress has a crucial role in diabetic pathophysiology, therefore consuming naturally derived antioxidants as a remedial target. This study examines the naturally occurring antioxidant and antidiabetic of Olea europaea L. ethanolic leaves extract. Olea europaea L. leaves were macerated (OLE) by using absolute ethanol. Phytochemical and physiochemical analysis of OLE was screened using standard methods. The antioxidant effects were examined by DPPH (1, 1-diphenyl-2-picrylhydrazil) radical scavenging assay. In vitro antidiabetic was assayed by α-amylase enzyme inhibition study. Ethanolic extraction of OLE by maceration technique, 10% yield. Loss on drying, foreign organic matters and total ash value of OLE showed 2%, 0.2% and 16.5%, respectively. Phytochemical test on OLE confirmed saponin, flavonoid, glycoside, tannin, phenol and carbohydrate presences. The total phenolic and flavonoid contents of OLE is 490 mg GAE/g and 855 mg RUE/g of extract, respectively. OLE (IC₅₀ 38.37 ± 0.26 µg/ml) showed functional DPPH scavenging assay comparable to ascorbic acid (IC₅₀ 30.37 ± 0.17 µg/ml). In the alpha-amylase inhibitory activity, Acarbose showed an IC₅₀ value of 20.06 ± 0.19 µg/ml, while OLE portrayed an IC₅₀ value of 37.99 ± 0.15 µg/ml. The kinetic studies revealed that all samples at high concentrations reacted within a very short time, and a steady state was reached almost immediately. The lowest concentration showed slow kinetic behaviour implied longer periods before the constant state was reached. Molecular docking studies evidenced that most of the phenolic compounds of OLE interact with the active site of Human pancreatic α-amylase through the hydrogen bonding and hydrophobic interaction confirming the alpha-amylase inhibitory effect. The results suggest that Olea europaea L. has been a conceivable natural bioactive source as an antioxidant and an antidiabetic agent.     

Evaluation of sulfur, selenium and tellurium catalysts with antioxidant potential

Oxidative stress is implicated, either directly or indirectly, in the pathology of a range of human diseases. As a consequence, the development of efficient antioxidants for medical use has become increasingly important. We have synthesised a range of structurally related organo-sulfur, -selenium and -tellurium agents and demonstrated that a combination of electrochemical methodology, in vitro assays and cell culture tests can be used to rationalise the antioxidant activity of these catalytic agents. Based on its exceptionally low anodic oxidation potential (Epa) and high activity against the representative oxidative stressors tert-butyl hydroperoxide and peroxynitrite, 4,4'-dihydroxydiphenyltelluride is predicted to be a potent antioxidant. This compound exhibits a correspondingly high activity with a remarkably low IC50 value of 20 nM, when tested in PC12 cell culture using a bioassay indicative of the early stages of Alzheimer's disease.     

Polarographic reduction of some potential antidiabetic compounds

The polarographic reduction of 4-arylhydrazone-N′-benzysulphonyl-3-methyl-2-pyrazoline-5-ones gave two, two-electron transfer, well defined, well separated, diffusion controlled, irreversible waves in B.R. buffers of pH range 7.0–11.0. In acidic medium the E_1/2 values of the two waves are so close that only one 4-electron transfer, well defined, diffusion controlled, irreversible waves is obtained. The reduction in these compounds takes place at the-NH-N=C-bond. The effect of substituents and its correlation with the Hammett substituent constant (σ) have also been studied.     

Enantiospecific synthesis of pseudoacarviosin as a potential antidiabetic agent

A pseudo-1,4'- N-linked disaccharide, pseudoacarviosin 5, was constructed via a key palladium-catalyzed coupling reaction of pseudoglycosyl chloride 8 (prepared from d-glucose via a novel direct intramolecular aldol addition in 12 steps) and pseudo-4-amino-4,6-dideoxy-alpha- d-glucose 9 (prepared from l-arabinose via an unusual trans-fused isoxazolidine-selective intramolecular nitrone-alkene cycloaddition in 11 steps). Pseudoacarviosin 5 has been shown to be a potent inhibitor of alpha-glucosidases, particularly the intestinal mucosal enzymes sucrase and glucoamylase of relevance to blood glucose control.     

Evaluation of potential antioxidant and effect of biomimetic nanoscale silver particles on opportunistic fungi

Green approach for tailoring quasi spherical Ag nanoparticles (NPs) from leave (L) and rhizome (Rh) of Alpinia Calcarata (AC) was explored due to increasing demand for eco-friendly, efficient, and cost effect antioxidant/antifungal agents. The fabricated Ag particles depicted dose dependence of activities. DPPH radical scavenging rate was about 69.57% and 77.1% at 1.85 × 10^?2 M Ag NPs ACL and Ag NPS ACRh respectively which are attributed to simultaneous activity of surface coverage and small Ag particles. Furthermore, disc-diffusion studies revealed remarkable comparable inhibitory effects of the synthesized Ag NPs ACL and Ag NPS ACRh on all the tested MTCC-4878, MTCC-1811, MTCC-7880 fungi.     

Oxidation of ring in a lupeol

Lupeone and lupanone on autoxidation yielded the corresponding disphenols in almost quantiative yield. Hydrogenation of lupanone diosphenol yielded a dihydro derivative which on acetylation yielded 3β-acetoxy lupan 2-one.     

Chemical composition and In vitro antioxidant and antidiabetic activities of Eucalyptus Camaldulensis Dehnh. essential oil

The present study was designed to determine the composition of the essential oil of Eucalyptus camaldulensis Dehnh. leaves and to examine its in vitro antioxidant and antidiabetic activities. The chemical composition of the essential oil from Eucalyptus camaldulensis Dehnh. leaves was analyzed by GC/GC-MS, twenty-nine compounds representing 99.10% of the total oil were identified. The major components of the oil were p-cymene (68.43%), 1,8-cineole (13.92%), 1-(S)-α-pinene (3.45%) and R-(+)- limonene (2.84%). The antioxidant features of the essential oil were evaluated using inhibition of 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, and superoxide radicals, inhibition of hydrogen peroxide and lipid peroxidation assays. We also studied α-amylase and α-glucosidase inhibition in vitro to assess the antidiabetic properties of the essential oil. Both α-amylase and α-glucosidase were inhibited by a non-competitive mechanism.     

The chemical components of Coreopsis tinctoria Nutt. and their antioxidant,antidiabetic and antibacterial activities

Abstract

Seventeen compounds were isolated from the capitula of Coreopsis tinctoria Nutt. with various column chromatographic methods and semi-preparative HPLC. Their structures were identified by the spectroscopic data and comparison with literatures as 2′-hydroxy-4,4′-dimethoxy-chalcone; (1), isoliquiritigenin (2), eriodictyol (3), naringenin (4), maritimetin (5), butin (6), taxifolin (7), luteolin (8), 7,3′,4′-trihydroxyflavone (9), 8,3′,4′-trihydroxyflavone-7-O-β-d-glucoside (10), quercetin (11), quercetagitin-7-O-β-d-glucoside (12), quercetin-7-O-β-d-glucoside (13), 3,4-dihydroxybenzoic acid (14), caffeic acid (15), coreoside B (16), and myo-inositol (17). Compounds 1, 4, 9, 10 and 17 were isolated from C. tinctoria Nutt. for the first time. Compounds 7 and 12 possessed the highest antioxidant activity (IC₅₀?=?64.37 and 32.86?µg/ml, respectively) among the tested compounds (IC₅₀ value of positive control was 5.34?µg/ml). Compound 7 exhibited potent PTP1B enzymatic inhibition with an IC₅₀ value of 7.73?μg/ml (IC₅₀ value of positive control is 1.46?µg/ml). Furthermore, compound 5 showed strong antibacterial activity against the Gram-positive bacterium, S. aureus.     

Evaluation of novel coumarin-proline sulfonamide hybrids as anticancer and antidiabetic agents

Abstract

Cancer and diabetes are considered as two major diseases affecting human health worldwide. Various therapies are available for treatment of cancer and diabetes individually, peptide linkage containing proline sulfonamide can be a promising therapy for treatment of both cancer as well as diabetes. Here, we report design and synthesis of novel coumarin-proline sulfonamide derivatives as anticancer and antidiabetic agents. All the synthesized compounds were screened for their anticancer activity against lungs cancer cell line (A549) and breast cancer cell line (MCF7) using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide dye (MTT)assay and antidiabetic activity using DPP-IV inhibition assay. Compound 16b showed excellent activity against breast cancer cell line (MCF7) with IC₅₀ value of 1.07?µM. All compounds showed moderate DPP-IV inhibition.     

Synthesis and in vitro antitumour activities of lupeol derivatives

Nine lupeol derivatives were synthesised and assayed in vitro for their antitumour activities against three human tumour cells lines, A549, LAC and HepG2. Of lupeol derivaties, six were new compounds, and five compounds against A549 cells, four compounds against HepG2 cells and three compounds against LAC cells were effective in reducing viability, and the most promising compounds 5, 6 and 9 exhibited high activities against lung and liver cancer cells, even higher activities than those of adriamycin.     

LC-MS characterization of bioactive metabolites from two Yemeni Aloe spp. with antioxidant and antidiabetic properties

Two Yemeni Aloe(s) have been investigated; the resin from A. perry Baker (APR, Socotran Aloe), and the gel from A. vera (AVG, Saber Yamaniis). LC-MS for APR identified aloin B, aloinoside B/A, homonataloin B and microdontin B/A as the major components, constituting 67.7% w/w of the extract. AVG showed the same pattern of anthrones (19.5% w/w), in addition to the chromones aloesin, aloeresin A, aloeresin D and aloeresin E. Dihydro-isocoumarin glucoside was identified in both Aloe species. Aloe extracts showed high antioxidant activity: DPPH (0.09 & 0.05 mM/g TE), ABTS (0.06 & 0.03 mM/g TE), and FRAP (20.5 & 15.5 mM Fe⁺²E), for APR & AVG, respectively. The antidiabetic properties was evaluated through inhibition of α-glucosidase enzyme. APR showed inhibitory activity with IC₅₀ 0.76 μg/mL higher than AVG (IC₅₀ 0.76 mg/mL). Aloin A showed the highest inhibitory activity with IC₅₀ 0.34 mg/mL that was higher than acarbose (0.54 mg/mL) the positive control, indicating that the activity of Aloe extract is linked to the aloin and other anthrone compounds. These findings highlight the phytochemical profile, antioxidant and potential antidiabetic activity of the Yemeni Aloe species and draw attention to their potential application in food, medicine and cosmetic products.     

Evaluation of the antioxidant potential of Salvia miltiorrhiza ethanol extract in a rat model of ischemia-reperfusion injury

The present study was undertaken to evaluate the protection potential of ethanol extract of Salvia miltiorrhiza (SMEE) against oxidative injury in the ischemia-reperfusion (I/R) model of rats in vivo. Rats were divided into six groups of 10 rats each. Group I/R model and sham were fed with a standard rat chow, groups SMEE I and SMEE II were fed with a standard rat chow and 400 or 800 mg/kg b.w. ethanol extract for 12 days before the beginning of I/R studies. Positive control group was fed with a standard rat chow and salvianolic acid B (55 mg/kg b.w.) or tanshinone II-A (55 mg/kg b.w.) for 12 days before the beginning of I/R studies. To produce I/R, the left anterior descending artery (LAD) was occluded in anesthetized rats for 15 min, followed by 120 min reperfusion. Infarct sizes were found significantly decreased in SMEE-treated and positive control groups compared to I/R model group. Serum AST, LDH and CK-MB activities were significantly reduced and myocardium Na+-K+ ATPase, Ca2+-Mg2+ ATPase activities and antioxidant enzyme activities (SOD, CAT, GSH-Px) were markedly increased in SMEE-treated and salvianolic acid B or tanshinone II-A positive control groups compared to the I/R model group. Pretreatment of S. miltiorrhiza ethanol extract and salvianolic acid B or tanshinone II-A dose-dependently reduced significantly myocardium MDA level, ROS and NOS activities and enhanced myocardium GSH level in I/R rats compared to I/R rats model. In conclusion, we clearly demonstrated that S. miltiorrhiza ethanol extract pretreatment can decrease oxidative injury in rats subjected to myocardial I/R.     

Synthesis and structure of an acetylene derivative of lupeol

The synthesis and x-ray crystal structure of 3-acetoxy-29-norlup-20(30)-yne were carried out.     

Polarographic reduction of some potential antidiabetic compounds with more than one reduction site

The polarographic reduction of a number of N'-guanylarylazopyrazole nitrates has been studied over a range of concentration and pH values. The effect of substituent groups on the value of the half wave potential has been determined.     

Synthesis of lupeol derivatives and their antileishmanial and antitrypanosomal activities

The natural product lupeol 1 was isolated from aerial parts of Vernonia scorpioides with satisfactory yield, which made it viable to be used as starting material in semisynthetic approach. Ten lupeol derivatives 2–11 were prepared by classical procedures. Including, five new esters derivatives 7–11, which were obtained by structural modifications in the isopropylidene fragment. All semisynthetic compounds and lupeol 1–11 were confirmed by ¹H NMR, ¹³C NMR and HRMS. Their antiprotozoal activity was evaluated in vitro against L. amazonensis and T. cruzi. Derivative 6 showed the best antitrypanosomal activity (IC₅₀ = 12.48 μg/mL) and the lowest cytotoxic derivative (CC₅₀ = 161.50 μg/mL). The mechanism of action of the most active derivatives (4, 6 and 11) is not dependent from the enzyme trypanothione reductase.     

Theoretical and experimental analysis of the antioxidant features of diarylhydrazones

Structural and energetic features of a series of 15 diarylhydrazone derivatives were studied via density functional theory (DFT) in order to identify the key features that most likely contribute to their antioxidant effect. Theoretical calculations were carried out at the B3LYP/6-31G(d,p) level. The calculated physicochemical parameters included the ionization potential, N-H dissociation enthalpy, proton affinity, HOMO/LUMO energies, and the band gaps of the most stable conformation of the compounds. To assess the contribution of these factors to the in vitro activity, the compounds were synthesized and their antioxidant activity was also determined in three commonly used assays. The hydrazones were evaluated for their radical scavenging against the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), and peroxyl (ORAC assay) radicals. The experimental radical scavenging data of the compounds have been then plotted against the physicochemical characteristics and based on the obtained fits conclusions have been drawn regarding the relative importance of the respective factors.