The Structure-Activity Relationship of the Antioxidant Peptides from Natural Proteins.

Peptides derived from dietary proteins, have been reported to display significant antioxidant activity, which may exert notably beneficial effects in promoting human health and in food processing. Recently, much research has focused on the generation, separation, purification and identification of novel peptides from various protein sources. Some researchers have tried to discover the structural characteristics of antioxidant peptides in order to lessen or avoid the tedious and aimless work involving the ongoing generated peptide preparation schemes. This review aims to summarize the current knowledge on the relationship between the structural features of peptides and their antioxidant activities. The relationship between the structure of the precursor proteins and their abilities to release antioxidant fragments will also be summarized and inferred. The preparation methods and antioxidant capacity evaluation assays of peptides and a prediction scheme of quantitative structure-activity relationship (QSAR) will also be pointed out and discussed.

Ultrasound-assisted extraction of Mangiferin from Mango (Mangifera indica L.) leaves using response surface methodology.

Mangiferin is a xanthone widely distributed in higher plants showing antioxidative, antiviral, anticancer, antidiabetic, immunomodulatory, hepatoprotective and analgesic effects. In the present study, an ultrasonic-assisted extraction method was developed for the effective extraction of mangiferin from mango leaves. Some parameters such as ethanol concentration, liquid-to-solid ratio, extraction temperature, and extraction time were optimized by single-factor experiment and response surface methodology. The optimal extraction conditions were 44% ethanol, the liquid-to-solid ratio was 38:1, and extraction for 19.2 min at 60 °C under ultrasound irradiation of 200 W. Under optimal conditions, the yield of mangiferin was 58.46 ± 1.27 mg/g. The results obtained are helpful for the full utilization of mango leaves, and also indicated that ultrasonic-assisted extraction is a very useful method for the extraction of mangiferin from plant materials.

[Effect of Aloe emodin on invasion and metastasis of high metastatic breast cancer MDA-MB-231 cells].

OBJECTIVE: To investigate the effect of Aloe emodin (AE) on the invasive and metastatic abilities of human high metastatic breast cancer MDA-MB-231 cells. METHODS: MTT assay was used to evaluate the viability of MDA-MB-231 cells after treated with AE for 6 h and 24 h. The adhesive potential of MDA-MB-231 cells to FN and LN was tested by cell-matrix adhesion assay. The effect of AE on invasion of MDA-MB-231 cells was measured by Transwell chamber assay. Scratch wound healing assay was applied to determine the effect on migration of MDA-MB-231 cells. The effect of AE on MDA-MB-231 lung metastasis was determined on an experimental metastatic model. RESULTS: 80 micromol/L AE significantly inhibited the invasion, adhesion to FN, LN of MDA-MB-231 cells in vitro, the inhibitory rates were (52.98 +/- 5.46)%, (34.99 +/- 2.63)%, (28.73 +/- 7.00)%, respectively. After 24 h treatment, AE significantly inhibited the migration of MDA-MB-231 cells. The number and volume of lung metastatic nodules formed by MDA-MB-231 cells after 80 micromol/L AE 24 h treatment were decreased compared with control group. CONCLUSION: AE can suppress the metastasis of MDA-MB-231 cells. Their mechanisms may be related to the inhibition of the capabilities of invasion and migration of MDA-MB-231 cells.

[Effect of seven kinds of flavonoids on recombinant human protein tyrosine phosphatase].

OBJECTIVE: To observe the effects of seven kinds of flavonoids on recombinant human phosphatase of regenerating liver-3 activity. METHODS: The inhibitory effect of flavonoids was tested by DiFMUP assay. Calculation of IC50 values was performed according to the law of semi-effect-probit. RESULTS: Myricetin and gossypin could significantly inhibit recombinant PRL-3 activity in a concentration dependent manner with IC50 values of 55.54 and 68.86 micromol/L, respectively. Quercetin, luteolin and 7,8-Dihydroxyflavone had a weak inhibitory effect with IC50 values of 113.38, 151.56 and 249.49 micromol/L. respectively. While 3-hydroxyflavone and 6-hydroxyflavone had no significant effect on PRL-3 activity. Structure activity study indicated that C4 and C7 hydroxyls on the flavone skeleton were key functional groups to influencing PRL-3 inhibotory activity. The inhibitory effect of flavonoids on PRL-3 was increased with the number of hydroxyl group. CONCLUSION: Myricetin and gossypin were two strong inhibitors on recombinant human protein tyrosine phosphatase PRL-3.

[Study on the effect of resveratrol on metastasis-associated ability of ovarian carcinoma HO-8910PM cells in vitro].

OBJECTIVE: To investigate the inhibitory effect of resveratrol on the metastasis-associated ability of human highly metastatic ovarian carcinoma HO-8910PM cells in vitro. METHODS: MTf assay was used to examine the cytotoxicity of resveratrol in HO-8910PM cells; Transwell Chamber assay was performed to determine the effect on invasion and migratory capacity of the cells by resveratrol; Effect on adhesion potential of HO-8910PM cells was tested by cell-Matrigel adhesion assay. RESULTS: Resveratrol showed no cytotoxicity on HO-8910PM cells after 6 h treatment. Resveratrol significantly inhibited migration and adhesion capacity of HO-8910PM cells in vitro. Their inhibitory rates after treated with the chemical of 100 micromol/L for 6 h were (30. 1 +/- 10. 8) % ,(34. 27 +/- 1. 28)% , respectively. However, Resveratrol had no effect on invasion capacity of HO-8910PM cells. CONCLUSION: Resveratrol can inhibit the migration and adhesion of HO-8910PM cells in vitro. Resveratrol might be a potential drug to inhibit tumor metastasis.

Clinical Application of Dual-Energy Spectral Computed Tomography in Detecting Cholesterol Gallstones From Surrounding Bile.

RATIONALE AND OBJECTIVE: This study aimed to investigate the clinical value of spectral computed tomography (CT) in the detection of cholesterol gallstones from surrounding bile. MATERIALS AND METHODS: This study was approved by the institutional review board. The unenhanced spectral CT data of 24 patients who had surgically confirmed cholesterol gallstones were analyzed. Lipid concentrations and CT numbers were measured from fat-based material decomposition image and virtual monochromatic image sets (40-140 keV), respectively. The difference in lipid concentration and CT number between cholesterol gallstones and the surrounding bile were statistically analyzed. Receiver operating characteristic analysis was applied to determine the diagnostic accuracy of using lipid concentration to differentiate cholesterol gallstones from bile. RESULTS: Cholesterol gallstones were bright on fat-based material decomposition images yielding a 92% detection rate (22 of 24). The lipid concentrations (552.65 ± 262.36 mg/mL), CT number at 40 keV (-31.57 ± 16.88 HU) and 140 keV (24.30 ± 5.85 HU) for the cholesterol gallstones were significantly different from those of bile (-13.94 ± 105.12 mg/mL, 12.99 ± 9.39 HU and 6.19 ± 4.97 HU, respectively). Using 182.59 mg/mL as the threshold value for lipid concentration, one could obtain sensitivity of 95.5% and specificity of 100% with accuracy of 0.994 for differentiating cholesterol gallstones from bile. CONCLUSIONS: Virtual monochromatic spectral CT images at 40 keV and 140 keV provide significant CT number differences between cholesterol gallstones and the surrounding bile. Spectral CT provides an excellent detection rate for cholesterol gallstones.

Anticancer effects of morin-7-sulphate sodium, a flavonoid derivative, in mouse melanoma cells.

BACKGROUND: Increasing evidence supports the anticancer effects of morin in vitro and in vivo. However, the role of morin-7-sulphate sodium (NaMoS), a water-soluble flavonoid derivative synthesized from morin remains unclear. The present study investigated the tumor suppression by NaMoS in mouse melanoma cells. MATERIALS AND METHODS: We synthesized the flavonoid derivative morin-7-sulphate sodium according to the method described for quercetin-sulphate derivative, and further isolated, purified and identified the compound. Cell proliferation in vitro was assessed using a CCK-8 assay. The wound healing assay was performed to evaluate cell motility, and flow cytometry was used to detect cellular apoptosis. Protein levels of vimentin, matrix metalloproteinase 9 (MMP9), phosphorylation of Akt1/2/3 (p-Akt1/2/3), extracellular signal-regulated kinase 1/2 (p-ERK1/2) and Caspase3 in B16F10 cells were detected by immunohistochemistry and Western blot. RESULTS: The results suggest that cell proliferation was markedly decreased in NaMoS-treated groups (1, 10, 25, 50, 100, 500, 1000µM) in a dose-dependent manner compared with the Control group and the IC50 was 221.67µM at 48h. NaMoS at 200µM concentration significantly inhibited the invasion and promoted apoptosis of B16F10 cells. Moreover, protein level of Caspase3 increased significantly in B16F10 cells treated by NaMoS. Immunohistochemistry and Western blot further confirmed that NaMoS decreased the expression of vimentin, MMP9, p-Akt1/2/3 and p-ERK1/2 in B16F10 cells. CONCLUSIONS: This study provides robust evidence that NaMoS, a water-soluble flavonoid, manifests anticancer properties and may act as a signal transduction inhibitor in melanoma cells.

Inhibitory effect of aloe-emodin on metastasis potential in HO-8910PM cell line.

Aloe-emodin (AE) has been demonstrated to have antitumor activity in several tumor cells. However, no information is available on the effect of AE on metastasis in human carcinoma cells. This study was designed to investigate the inhibitory effect of AE on the metastasis potential of HO-8910PM cell line in vitro, and the role of AE in focal adhesion kinase (FAK) expression. Transwell chamber assay was performed to determine the effect of AE on the invasion and migration capacities of the cells. The effect of AE on the adhesion potential of HO-8910PM cells was determined by cell-Matrigel adhesion assay. We found that AE significantly inhibited invasion, migration, and adhesion capacities of HO-8910PM cells, and, furthermore, reduced the protein and mRNA expression of FAK. These findings suggest that the possible mechanistic explanation for the inhibitory effect of AE on metastasis potential in vitro is involved in FAK expression.

[Inhibitory effect of cantharidin on invasion and metastasis of highly metastatic ovarian carcinoma cell line HO-8910PM].

BACKGROUND & OBJECTIVE: Cantharidin, a natural toxin, has specific antitumor actions. Many researches confirmed that nuclear factor-kappaB (NF-kappaB) closely relates with invasion and metastasis of tumor. This study was designed to investigate inhibitory effect of cantharidin on metastasis-related ability of human highly metastatic ovarian carcinoma cell line HO-8910PM, and its mechanism. METHODS: MTT assay was used to examine cytotoxicity of cantharidin on HO-8910PM cells. Effect of cantharidin on adhesion potential of HO-8910PM cells was tested by cell-Matrigel adhesion assay. Transwell chamber assay was performed to determine its effect on invasion and migration capacities of HO-8910PM cells. Protein levels of NF-kappaB P65 subunit and vascular endothelial growth factor (VEGF) were assessed by Western blot. RESULTS: After 6-h treatment of 20 micromol/L of cantharidin, inhibitory rate of HO-8910PM cells was (8.4+/-2.2)%, inhibitory rates of invasion, migration, and adhesion capacities of HO-8910PM cells were (38.8+/-1.7)%, (40.3+/-5.6)%, and (55.1+/-6.7)%, respectively; protein levels of NF-kappaB P65 subunit and VEGF were down-regulated. CONCLUSIONS: Cantharidin can inhibit migration, invasion, and adhesion of HO-8910PM cells. Its possible mechanism may be involved in down-regulations of NF-kappaB P65 subunit and VEGF.