Asian Pacific Journal of Tropical Biomedicine

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Objective: To evaluate the potential immunomodulatory effects of an aqueous extract of Sesamum indicum seeds with regard to splenocyte proliferation, Th1/Th2 balance, macrophage function, and the cytotoxic activity of natural killer (NK) cells. Methods: Splenocyte proliferation was measured by [³H]- thymidine incorporation. Griess assay was performed to evaluate the production of nitric oxide by macrophages. The levels of cytokines secreted by splenocytes and macrophages were measured by ELISA. JAM assay was performed to examine the cytotoxic activity of NK cells against YAC-1 tumor cells. Results: Sesamum indicum significantly enhanced splenocyte proliferation in a dose-dependent manner. Sesamum indicum also increased and suppressed the secretion of Th1 and Th2 cytokines, respectively, by splenocytes. The secretion of key pro-inflammatory mediators (IL-6, TNFα, and nitric oxide) by primary macrophages was significantly inhibited by Sesamum indicum. Moreover, Sesamum indicum increased the cytotoxic activity of NK cells against YAC-1 tumor cells. Conclusions: Sesamum indicum shows potent immunomodulatory, anti-inflammatory, and anti-cancer effects. Constituents of Sesamum indicum may be used as effective therapeutic agents in regulating immune reactions implicated in various infectious and non- infectious conditions including cancer.

Objective: To evaluate the anti-angiogenic and anticancer activities of Psidium guajava leaf extracts against angiogenesis-dependent colorectal cancer. Methods: Three extracts were produced using distilled water, ethanol, and n-hexane as solvents. The extracts were physically characterised through gas chromatography–mass spectrometry, ultraviolet-visible spectroscopy, and Fourier transform infrared spectroscopy. Their antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl, total phenolic content, and total flavonoid content assays. To assess their anti-angiogenic activity, cell viability and rat aortic ring assays were conducted, while cell migration, tube formation, colony formation, and VEGF ELISA assays were conducted to elucidate their effects on different aspects of angiogenesis. Molecular docking was used to assess the anti- angiogenic potential of some possible compounds in the extracts. Tumour spheroid assay was used to assess the extracts’ potential as a treatment for colorectal cancer. Results: The ethanol extract showed the best antioxidant activity. The distilled water and ethanol extracts exhibited more inhibitory activity against EA.hy926 cell viability and aortic ring microvessel growth. In addition, the ethanol extract performed significantly better than the distilled water extract against cell migration and colony formation, and VEGF expression of the cells was suppressed by the ethanol extract. Both the distilled water and ethanol extracts showed significant inhibitory effect on EA.hy926 tube formation and tumour spheroids consisting of EA.hy926 and HCT116 cells. The ethanol extract contained β-caryophyllene and β-elemene by phytochemical analysis and subsequent docking studies, which may contribute to its anti-angiogenic activity. Conclusions: The ethanol extract of Psidium guajava has potential in the treatment of colorectal cancer through the inhibition of angiogenesis.

Objective: To investigate the antibiofilm activity of alpha- mangostin (AMG) loaded nanoparticle (nanoAMG) against dental caries pathogen Streptococcus mutans. Methods: AMG was isolated from the peels of Garcinia mangostana L. using silica gel columns and chemically analysed by high performance liquid chromatography and nuclear magnetic resonance. NanoAMG was prepared using the solvent evaporation method combined with high-speed homogenization. The nanoparticles were characterized using dynamic light scattering, field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FTIR). The toxicity of nanoAMG in fibroblast NIH/3T3 cell line was determined using MTT method. The antibiofilm effect of nanoAMG was determined through the evaluation of biofilm formation by Streptococcus mutans using a 96-well plate. Biofilm biomass was quantified using crystal violet. Cell viability was observed under confocal microscopy using LIVE/DEAD BacLight staining. Moreover, gene expression was determined by quantitative real-time PCR and membrane permeabilization activity by measuring the uptake of o-nitrophenol- β-D-galactoside. Results: NanoAMG size was in a range of 10-50 nm with a polydispersity index of < 0.3 and zeta potential value of -35.2 mV The size and the incorporation of AMG in the nanoparticles were confirmed by FE-SEM and FTIR analyses. The IC₅₀ values of the test agents on NIH/3T3 cells were (9.80 ± 0.63) μg/mL for AMG and (8.70 ± 0.81) μg/mL for nanoAMG, while no toxicity was generated from excipients used to prepare nanoparticles. In the early stage of biofilm formation, treatment with 6.25 μmol/L nanoAMG caused a reduction in biofilm biomass up to 49.1%, compared to 33.4% for AMG. In contrast, biofilms at the late stage were more resistant to the test agents. At 96 μmol/L (= 10 × MIC), nanoAMG reduced only 20.7% of biofilm biomass while AMG did not show any effect. Expressions of gtfB and gtfC genes involved in biofilm formation were down-regulated 3.3 and 12.5 folds, respectively, compared to AMG (2.4 and 7.6 folds, respectively). LIVE/DEAD BacLight fluorescence staining and microscopy observation indicated that biofilm cells were killed by both nanoAMG and AMG at 48 μmol/L (= 5 × MIC). In addition, membrane permeabilization activity was increased in a time dependent manner and higher in nanoAMG treated cells compared to AMG. Conclusions: AMG coated nanoparticle can enhance AMG bioactivity and can be used as a new and promising antibiofilm agent.

Objective: To compare the anti-proliferative effect of sodium thiosulfate on human colorectal cancer cells (HT-29) and normal small intestine cells (IEC6). Methods: Cells (HT-29 and IEC6) were treated with different concentrations of sodium thiosulfate ranging from 0.5 mM to 80 mM for 24 h. Cell viability was measured via crystal violet and MTT assays. HT-29 cells were further treated in the presence and absence of mitochondrial electron transport chain (ETC) inhibitors, K_ATP channel opener and closer and H₂S inhibitors for 24 h followed by sodium thiosulfate in order to study their respective roles in the anti-proliferative activity of sodium thiosulfate. Results: The IC₅₀ values of sodium thiosulfate on HT-29 cells were 40.93 mM and 42.45 mM by crystal violet and MTT assay whereas, in the case of IEC6 cells, the values were 45.17 mM and 47.22 mM. The inhibition of endogenous H₂S enzymes and K_ATP channel induced no change in the anti-proliferative capacity of sodium thiosulfate. However, the anti-proliferative activity of sodium thiosulfate was enhanced in the presence of mitochondrial ETC inhibitors. Conclusions: HT-29 cell growth is effectively attenuated by sodium thiosulfate and the anti-proliferative activity of sodium thiosulfate is enhanced in the presence of mitochondrial ETC inhibitors.

Objective: To assess the anti-inflammatory efficacy of ferruginol on dextran sulfate sodium (DSS) stimulated ulcerative colitis mice. Methods: Ulcerative colitis was induced in C57BL/6J mice by administering 2% of DSS through drinking water for 7 d. The mice in the treatment group were treated with DAA+50 mg/kg/day ferruginol orally. In the positive control group, sulfasalazine (50 mg/kg/day) was used alongside with DSS. After induction, the bodyweight, character of stool and feces occult blood were recorded daily, the disease activity index was calculated, and the colon length, colon weight, and spleen weight were recorded. The myeloperoxidase activity was assayed by spectrophotometry. Interleukin (IL)-6, IL-1β, and tumor necrosis factor-a were determined by ELISA method, and nuclear factor-κB, cyclooxygenase-2, matrix metalloproteinases-9, and inducible nitric oxide synthase by Western blotting assays. Results: Ferruginol significantly increased the bodyweight, colon weight, colon length, and decreased disease activity index and spleen weight. It exhibited anti-inflammatory activity against DSS induced ulcerative colitis in mice by reducing the activities of myeloperoxidase, tumor necrosis factor-α, nuclear factor-κβ, IL-1β, cyclooxygenase-2, matrix metalloproteinases-9, IL-6, and inducible nitric oxide synthase. Conclusions: Ferruginol could be used to treat ulcerative colitis by attenuating the inflammation in colon cells and maintaining colonic mucosal barrier integrity.

Online since 13^th December 2017