Objective: To investigate antidiabetic and antioxidant activities of the extract and fractions from Vietnamese red seaweed Laurencia dendroidea. Methods: The seaweed Laurencia dendroidea was extracted by using microwave-assisted extraction method in 80% methanol. The seaweed extract was then fractionated using different solvents (n-hexane, chloroform, ethyl acetate, butanol and water). These obtained fractions were evaluated for α -glucosidase inhibitory and antioxidant activities. Antioxidant activities were tested using DPPH, nitric oxide radical scavenging and metal chelating assays. The enzyme inhibition mode was determined using Lineweaver-Burk plot. For acidic and thermal stabilities, the ethyl acetate fraction was treated at pH 2.0 and 100 °C, respectively. The residual inhibitory activity of the fraction was calculated based on the initial inhibitory activity. For in vivo antidiabetic activity, mice were divided into four groups, including normal control, diabetic control, diabetic mice treated with ethyl acetate fraction and diabetic mice treated with gliclazide. Blood glucose level of treated mice during acute and prolonged treatments was measured. To evaluate the toxicity of the ethyl acetate fraction, the body weight changes and activities of liver function enzymes (aspartate transaminase, alanine transaminase and gamma-glutamyl transferase) were carried out. Results: The extract of Laurencia dendroidea showed strong α-glucosidase inhibitory and DPPH radical scavenging activities. Methanolic concentrations affected both α-glucosidase inhibitory and antioxidant activities. A 80% aqueous methanol was the suitable solvent for extraction of enzyme inhibitors and antioxidants. Among solvent fractions, ethyl acetate fraction had the highest inhibitory activities against α -glucosidase with a mixed type of inhibition and the strongest antioxidant activities, and was stable under acidic and thermal conditions. The ethyl acetate fraction treated diabetic mice significantly reduced blood glucose level compared with the diabetic control group (13.16 mmol/L vs. 22.75 mmol/L after 3 hours of treatment). Oral administration of ethyl acetate fraction did not exhibit toxicity at a dose of 100 mg/kg body weight as determined by body weight changes and liver biochemical parameters. Conclusions: Laurencia dendroidea could be a potential source for production of antidiabetic and antioxidative agents.

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Objective: To synthesize silver nanoparticles with Colocasia esculenta as a reducing agent and to evaluate their effect against Culex quinquefasciatus and Chironomus sp. Methods: The aqueous extract of Colocasia esculenta stem was used for nanosynthesis. The synthesized nanoparticles were characterized by UV-Vis spectrophotometry, Fourier-transform infrared spectroscopy, scanning electron microscope, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and Zeta potential studies. The toxicity of Colocasia esculenta stem extract and the synthesized silver nanoparticles was evaluated against the larval stages of target human filarial vector Culex quinquefasciatus and non-target Chironomus sp. Results: Scanning electron microscopy and transmission electron microscopy studies revealed almost spherical shape of the synthesized silver nanoparticles with size ranging from 13-50 nm. After 24 hours of exposure, the LC₅₀ and LC₉₀ of the plant extract against 4th instars larvae of Culex quinquefasciatus were 745.56 mg/L and 1 258.28 mg/L, respectively, which were higher than those of synthesized silver nanoparticles (5.17 mg/L and 17.32 mg/L after 24 h; 1.58 mg/L and 13.01 mg/L after 48 h). In addition, the LC₅₀ and LC₉₀ of silver nanoparticles against Chironomus sp. were 9.71 mg/L and 23.15 mg/L after 24 h as well as 2.38 mg/L and 19.49 mg/ L after 48 h, respectively. Conclusions: The aqueous stem extract of Colocasia esculenta is a good agent for synthesis of silver nanoparticles, which are almost spherical with size less than 30 nm. The synthesized nanoparticles show good larvicidal activity without any harmful effect on non-target species.

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Objective: To identify the potential target and mechanisms of hesperidin in MCF-7 estrogen receptor-positive breast cancer cells using bioinformatics approaches. Methods: Gene expression profiles were accessed from public database GSE85871. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was carried out with Database for Annotation, Visualization and Integrated Discovery. The protein-protein interaction network was analyzed by STRING-DB and visualized by Cytoscape. Transcription factor regulatory networks were constructed from TRED, TRRUST, RegNetwork and visualized by Cytoscape. Drug association analysis was conducted by WebGestalt. Results: GO and KEGG pathway enrichment analysis revealed biological processes, cellular components and molecular functions that were related to cancer and estrogen signaling pathways. KEGG pathway enrichment analysis of the genes in transcription factor-differential expression genes regulatory network showed regulation of cancer, estrogen signaling pathways, epidermal growth factor receptor tyrosine kinase inhibitor resistance, and endocrine resistance. Moreover, drug association analysis revealed that hesperidin affected the expression of the same gene as raloxifene. Conclusions: Hesperidin targets estrogen receptor signaling in estrogen receptor-positive breast cancer cells. Results of this study could trace the molecular mechanism of hesperidin in estrogen receptor-positive breast cancer cells and integrative bioinformatics analysis could accelerate drug discovery and development.

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Objective: To explore the effects of kelulut honey on bone structure and histomorphometry against glucocorticoid-induced osteoporosis. Methods: Thirty-five male rats were used (n = 7). Twenty-eight adrenalectomized rats were divided into four groups; each group was given normal saline 0.9% (negative control), calcium water (positive control), kelulut honey (200 mg/kg/day and 400 mg/kg/day, respectively) treatment, respectively. All of them were administered with intramuscular injection of dexamethasone (120 μg/kg/day) to induce osteoporosis. Seven sham operated rats were given vehicle palm olein 0.05 mL/100 g/day by intramuscular injection and 0.1 mL/kg/day orally. All the treatments were given daily for 2 month. Lipid peroxidation and oxidative stress enzymes were measured. In addition, bone structural and histomorphometry analyses were also conducted. Results: Two-month glucocorticoid treatment increased the level of malondialdehyde and decreased superoxide dismutase significantly. No significant changes were found in the activities of catalase and glutathion peroxidase. Bone volume/tissue volume and trabecular number were significantly reduced while trabecular separation of the femoral bones was increased which corresponded to the decreased number of osteoblast surface after two months of receiving glucocorticoid treatment. Kelulut honey treatment restored the level of superoxide dismutase and reduced malondialdehyde significantly (P<0.05). Moreover, kelulut honey increased bone volume/tissue volume, trabecular number and decreased trabecular separation significantly (P<0.05), which were further confirmed by increased osteoblast surface and decreased osteoclast surface number (P<0.05). Conclusions: Kelulut honey may have potential bone protective effect, and may be a prophylaxis against glucocorticoid-induced osteoporosis.

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Objective: To evaluate the anti-inflammatory potential of peptide/polypeptide fraction of Aloe vera through in vitro and in vivo studies. Methods: The peptide/polypeptide fraction from Aloe vera was obtained through trichloroacetic acid precipitation. The anti-inflammatory property of the peptide/polypeptide fraction was tested by protein denaturation, membrane stabilization assays. The effect of the fraction on RAW 264.7 cell viability was examined by MTT assays. The nitric oxide level was determined through Griess reagent. TNF-α and IL-6 levels were estimated using ELISA kits. In vivo studies were carried out in male Wistar rats through injection of Freund’s adjuvant in the hind paw. Paw edema was measured through the Vernier scale and levels of alanine aminotransferase, aspartate transaminase, TNF-α, IL-6, and secretory phospholipase A2 were estimated through their respective kits after fourteen days of treatment. GraphPad Prism6 was used for analyzing the results. Results: The peptide/polypeptide extract inhibited protein denaturation with an IC₅₀ value of (218.9±15.6) μg/mL and stabilized the membrane of red blood cells with an IC₅₀ value of (275.9±19.1) μg/mL. The extract showed no changes in cell morphology or cytotoxicity up to the concentration of 20 μg/mL in MTT assays. The peptide/polypeptide fraction markedly reduced the levels of proinflammatory markers and mediators in both in vitro and in vivo studies. Conclusions: The results indicate that the peptide/polypeptide fraction of Aloe vera has anti-inflammatory property through inhibition of inflammatory markers and mediators responsible for NF-κB and mitogen-activated protein kinase pathways.

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Objective: To investigate the antioxidant efficacy of oral orientin on 900 MHz radiofrequency-electromagnetic radiation-induced oxidative stress in mice. Methods: The mice were randomly allotted into 5 groups consisting of 7 mice each. The deionised water and radiofrequency electromagnetic radiations (RF-EMR) groups were administered with deionised water while orientin was administered to the RF-EMR + low dose of orientin group (10 mg/kg), RF-EMR + high dose of orientin group (20 mg/kg) and high dose of orientin group (20 mg/kg). All the groups except deionised water and high dose groups were exposed to 900 MHz radiofrequency-electromagnetic radiation for 28 consecutive days (1 h/day). Learning and memory was assessed via the step-down inhibitory avoidance task. Activities of lipid prexidation and antioxidant enzymes were measured using kits. Results: Radiofrequency electromagnetic radiation caused impairment in learning and memory and reduced activities of brain antioxidant enzymes, increased lipoperoxidation and corticosterone concentration as well as histopathological aberrations in the hippocampal tissues. Conversely, orientin alleviated learning and memory deficit, improved the activities of endogenous antioxidant enzymes and mitigated brain lipoperoxidation and neuronal degeneration in mice exposed to radiofrequency electromagnetic radiation. Conclusions: Orientin alleviates learning and memory impairment due to radiofrequency electromagnetic radiation in mice by improving antioxidant defence mechanism and may be considered as a promising therapeutic agent for improving the antioxidant system of people living in radiofrequency electromagnetic radiation-prone environment.

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