A Modified Method for Measuring Root Iron Reductase Activity Under Normal Laboratory Conditions

Based on the strong chelating property of bathophenanthroline disulfonic acid (BPDS) with root chelate reductase activity is usually measured with a spectrophotometer using MES (2-morpholinoethanesulfonic acid) or HEPES (2-(4-(2-Hydroxyethyl)-1-piperazinyl) ethanesulfonic acid) buffer in the dark because of high autoreduction rate of in the presence of light. However, the exclusion of light is inconvenient, especially when analyzing a large number of samples. The objective of this study was to develop a new method for determination of root reductase activity under normal laboratory conditions using a suitable buffer composition and concentration to eliminate the autoreduction of A modified method using a Tris (2-amino-2-hydroxymethyl-1,3-propanediol) buffer at pH 7.5 instead of MES or HEPES buffer and a decreased FeEDTA (Fe ethylene diamine tetraacetic acid) concentration of 50 μmol L-1 was developed. The autoreduction of using the Tris buffer was undetectable for temperatures at 4 and 28 °C and was also much lower than that using the other buffers even with sunlight during measurement of reduction. Furthermore, the differences in reductase activity among 5 plant species and 14 red clover cultivars (Trifolium pratense L.) could be easily detected with the modified method. The method developed in this study to measure root Fe chelate reductase activity was not only effective and reliable but also easily managed under normal laboratory light conditions.

Structure-Activity Relationships in the Chelation Activity by Derivatives of 1,2-Dithiole-3-Thiones

The structure and electronic properties of a series of biologically active dithiolethiones （1） have been calculated using semi-empirical. Multi-linear regression analysis suggests that there is a reasonable correlation between the experimental activity of the derivatives against chelation activity and calculated properties such as the HOMO energies, molar refractivity, dipole moments and experimental partition coefficient. From the derived QSAR equations the 3-Methylthio-4p-Tolyle-1,2-Dithiolylium accompanying ion （CH3SO4） and 4-para-tolyl-1,2-dithiole-3-thione （2b and 2） are predicted to show the highest activity against chelation activity, while 3-Methylthio-5p-methoxy phenyl-1,2-Dithiolylium accompanying ion （I-） （3a） is predicted to be the least active in line with the experimental results.

Fruiting increases total content of flavonoids and antiproliferative effects of Cereus jamacaru D.C. cladodes in sarcoma 180 cells in vitro

Objective: To evaluate the influence of fruiting phenological stage on total flavonoid content, antioxidant activity, and antiproliferative effects of Cereus jamacaru(C. jamacaru)(mandacaru) cladodes and fruit. Methods: Fruit and cladodes at vegetative and fruiting stage of C. jamacaru were collected. The fruit was dissected and bark, pulp, and seeds were separated. Vegetative and fruiting cladodes, together with bark, pulp, and seeds were used to obtain five hydroalcoholic extracts. The extracts were investigated for total flavonoid content, using AlCl3 colorimetric method, antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging capacity and Fe^(2+) ion chelating activity, and in vitro antiproliferative effects(sarcoma 180 cells) by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2 H-tetrazolium bromide assay. Results: The extract of C. jamacaru cladodes at the fruiting stage showed higher flavonoid content compared to the other extracts. Seed extracts showed the highest antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) assays, and the extract of cladodes at vegetative stage showed better antioxidant activity in Fe^(2+) ion chelating activity. The extract of fruiting cladodes promoted higher antiproliferative effects compared to the other extracts. Conclusions: These findings suggest that fruiting increases the content of flavonoids and antiproliferative effects of C. jamacaru cladodes. Data reinforce the potential use of C. jamacaru cladodes and fruits as natural antioxidants and potent anticancer agent.

Investigation of hydrolysis conditions and properties on protein hydrolysates from flatfish skin

Response surface method （RSM）, based on Box-Behnken design, was used to optimize the enzymatic hydrolysis conditions of flatfish skin protein hydrolysates （FSPH）. Among the tested proteases, the combination of nutrase and trypsin was selected. The optimal hydrolysis conditions were as follows： pH 7.3, temperature 51.8℃, and the enzyme/substrate （E/S） ratio 2.5; under these conditions, the maximum peptide yield （PY） was 69.41 =1：0.43%. The physiochemical analysis showed that the amino acids （His, Asp and Glu） of FSPH accounted for 18.15%, and FSPH was a mixture of polypeptides mostly distributed among 900-2000 Da. FSPH could exhibit a 93% chelating effect on ferrous ion at a concentration of 400 gg/mL, and also a notable reducing power. This study showed bioprocess for the production of FSPH for the first time, which had a good potential for valuable ingredients in the food, cosmetic and medicine industries.