Asian Pacific Journal of Tropical Biomedicine

501-509

Authors: The Han Nguyen, Thi Huyen Nguyen, Van Minh Nguyen, Thi Lan Phuong Nguyen, Thi Van Anh Tran, Anh Duy Do, Sang Moo Kim

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.

518-523

Authors: Isaac O Akefe, Ibrahim L Yusuf, Victoria A Adegoke

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.

531-538

Authors: Adam Hermawan, Herwandhani Putri

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.