Antioxidant activity measurement and potential antioxidant peptides exploration from hydrolysates of novel continuous microwave-assisted enzymolysis of the Scomberomorus niphonius protein.

A novel continuous microwave-assisted enzymatic digestion (cMAED) method is proposed for the digestion of protein from Scomberomorus niphonius to obtain potential antioxidant peptides. In this study, bromelain was found to have a high capacity for the digestion of the Scomberomorus niphonius protein. The following cMAED conditions were investigated: protease species, microwave power, temperature, bromelain content, acidity of the substrate solution, and incubation time. At 400W, 40°C, 1500U·g-1 bromelain, 20% substrate concentration, pH 6.0 and 5min incubation, the degree of hydrolysis and total antioxidant activity of the hydrolysates were 15.86% and 131.49µg·mL-1, respectively. The peptide analyses showed that eight of the potential antioxidant peptide sequences, which ranged from 502.32 to 1080.55Da with 4-10 amino acid residues, had features typical of well-known antioxidant proteins. Thus, the new cMAED method can be useful to obtain potential antioxidant peptides from protein sources, such as Scomberomorus niphonius.

Suppressive effect of Sanmiao formula on experimental gouty arthritis by inhibiting cartilage matrix degradation: An in vivo and in vitro study.

Sanmiao formula (SM) is a compound prescription, which has been used in traditional Chinese medicine since the Ming Dynasty for gouty and rheumatoid arthritis treatments. However, no evidence has been unfolded to show the relationship between SM and gouty arthritis (GA), particularly inhibiting cartilage matrix degradation. In the present study, we undertook a characterization of anti-GA activity of SM using an in vivo rat model induced by potassium oxonate and cold bath together with in vitro studies with chondrocytes for further molecular characterization. Potassium oxonate and cold bath rats were treated with SM at doses of 7.2g/kg per day for 5days. SM treatments significantly suppressed the swelling rate and the severe pathologic changes in the joints of the animals in gout model. Inflammatory factors count by ELISA analysis, SM exhibited inhibition on IL-1ß and TNF-α. Moreover, histological analysis of the joints and SM-serum substantially interfered with the MSU-induced expression of glycosaminoglycans (GAG), up-regulated the content of proteoglycan. Importantly, SM interfered with GA-augmented expression of matrix metalloproteinases (MMPs) -3 and aggrecanases (ADAMTS)-4, which are considered to be key enzymes in cartilage matrix degradation, and simultaneously augmented GA-reduced tissue inhibitors of metalloproteinases (TIMPs) -1 and -3 expression in the joints and chondrocytes. Therefore, SM is looking forward to be a potential novel agent that could prevent cartilage matrix degradation effectively in gouty arthritis, and this provides a new target for development of new medicines.

Hydrolysis of acid and alkali presoaked lignocellulosic biomass exposed to electron beam irradiation.

In this study, synergetic effect of mild acid and alkali with electron beam irradiation (EBI) on the enzymatic hydrolysis of a selected grass biomass was assessed. Biomass samples prepared by soaking with 1% H2SO4, or 1% NaOH, were exposed to 75 and 150 kGy of EBI. Water presoaked biomass was used as control. Hydrolysis of pretreated samples was carried out using cellulase (15 FPU/g biomass) for 120 h. Structural changes were studied by FTIR and XRD analyses. Reducing sugar and glucose yields from enzymatic hydrolysis were significantly higher in acid and alkali presoaked EBI exposed samples. Theoretical glucose yield showed 40% increase from control in alkali presoaked EBI exposed (150 kGy) samples. Removal of hemicellulose, decreased crystallinity and structural changes were major factors for the combined treatment effect favoring the hydrolysis.

Determination of trace nickel in hydrogenated cottonseed oil by electrothermal atomic absorption spectrometry after microwave-assisted digestion.

Microwave digestion of hydrogenated cottonseed oil prior to trace nickel determination by electrothermal atomic absorption spectrometry (ETAAS) is proposed here for the first time. Currently, the methods outlined in U.S. Pharmacopeia 28 (USP28) or British Pharmacopeia (BP2003) are recommended as the official methods for analyzing nickel in hydrogenated cottonseed oil. With these methods the samples may be pre-treated by a silica or a platinum crucible. However, the samples were easily tarnished during sample pretreatment when using a silica crucible. In contrast, when using a platinum crucible, hydrogenated cottonseed oil acting as a reducing material may react with the platinum and destroy the crucible. The proposed microwave-assisted digestion avoided tarnishing of sample in the process of sample pretreatment and also reduced the cycle of analysis. The programs of microwave digestion and the parameters of ETAAS were optimized. The accuracy of the proposed method was investigated by analyzing real samples. The results were compared with the ones by pressurized-PTFE-bomb acid digestion and ones obtained by the U.S. Pharmacopeia 28 (USP28) method. The new method involves a relatively rapid matrix destruction technique compared with other present methods for the quantification of metals in oil.

Kinetics and mechanism of 2,3,5,4'-tetrahydroxystilbene-2-O-ß-d-glycoside (THSG) degradation in aqueous solutions.

The hydrolytic kinetics and degradation mechanism of 2,3,5,4'-tetrahydroxystilbene-2-O-ß-d-glycoside (THSG) extracted from Radix Polygoni Multiflori (a commonly used official Chinese herbal Heshouwu), were investigated using reversed-phase high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). The influences of pH (1.5-9.9), temperature (25-60°C) and irradiation on the hydrolysis of THSG were studied in aqueous solutions. The results showed that the degradation of THSG was pH-, temperature- and irradiation-dependent and all followed first-order kinetics. The effect of temperature on the rate of THSG degradation was characterized using the Arrhenius equation. Maximum stability of THSG was found at pH 1.5 (t(0.5)=47.57 d). THSG was unstable in alkaline and irradiation conditions. The active energy (E(a)) of THSG degradation in aqueous solution at pH 6.8 (most frequently adopted extract solvent) under lucifugal and irradiation conditions was 47.7kJmol(-1) and 25.3kJmol(-1), respectively. Three hydrolytic products of THSG were identified by LC-MS. Cis-trans isomerism took place under irradiation, and hydrolysis took place in acid-base conditions. Moreover, further oxidation on aglycon occurred after hydrolytic cleavage of phenolic glycoside in acidic conditions. The possible hydrolytic pathways of THSG are proposed.

Microwave-promoted hydrolysis of plant seed gums on alumina support.

Using a catalytic amount of potassium persulfate (1.48 x 10(-4)M), eight different seed gums were fully hydrolyzed on alumina support under microwave irradiation. The hydrolysis time varied between 1.33 and 2.33 min depending upon the seed gum structure. The used solid support could be easily separated from the hydrolyzates and recycled. However, under microwave field in an aqueous medium, the same amount of persulfate was unable to hydrolyze the seed gums. Solid-supported microwave hydrolysis has been compared with the microwave-enhanced aqueous hydrolysis (using K2S2O8 or 0.1N H2SO4) and also with the conventional hydrolysis procedures.