Chemical composition and physicochemical properties of tropical red seaweed, Gracilaria changii

A study on the proximate composition, minerals, vitamins, carotenoids, amino acids, fatty acids profiles and some physicochemical properties of freeze dried Gracilaria changii was conducted. It was discovered that this seaweed was high in dietary fiber (64.74 ± 0.82%), low in fat (0.30 ± 0.02%) and Na/K ratio (0.12 ± 0.02). The total amino acid content was 91.90 ± 7.70% mainly essential amino acids (55.87 ± 2.15 mg g1) which were comparable to FAO/WHO requirements. The fatty acid profiles were dominated by the polyunsaturated fatty acids particularly docosahexaenoic (48.36 ± 6.76%) which led to low x6/x3, atherogenic, and thrombogenic index. The physicochemical properties of this seaweed namely the water holding and the swelling capacity were comparable to some commercial fiber rich products. This study suggested that G. changii could be potentially used as ingredients to improve nutritive value and texture of functional foods for human consumption.and some physicochemical properties of freeze dried Gracilaria changii was conducted. It was discovered that this seaweed was high in dietary fibre (64.74 ± 0.82%), low in fat (0.30 ± 0.02%) and Na/K ratio (0.12 ± 0.02). The total amino acid content was 91.90 ± 7.70% mainly essential amino acids (55.87 ± 2.15 mg g1) which were comparable to FAO/WHO requirements. The fatty acid profiles were dominated by the polyunsaturated fatty acids particularly docosahexaenoic (48.36 ± 6.76%) which led to low x6/x3, atherogenic, and thrombogenic index. The physicochemical properties of this seaweed namely the water holding and the swelling capacity were comparable to some commercial fibre rich products. This study suggested that G. changii could be potentially used as ingredients to improve nutritive value and texture of functional foods for human consumption

ACE-Inhibitory and Antioxidant Activities of Hydrolysates from the By-Products of Hybrid Grouper (Epinephelus lanceolatus × Epinephelus fuscoguttatus)

Protein hydrolysates, generated from the by-products of fish, have received much attention over recent years, due to their antihypertensive and antioxidant activities. The potency of bioactive peptides, however, is affected by the type of enzyme selected and the duration of hydrolysis required to generate the protein hydrolysate. This study was aimed to investigate the effects of using four different enzymes (Alcalase, Proteinase K, Trypsin, and Pepsin) and hydrolysis time (1 - 48 h), on the ACE-inhibitory and antioxidant activities (hydroxyl radical scavenging activity and reducing power), of protein hydrolysates from the head and bones of hybrid grouper (Epinephelus lanceolatus × Epinephelus fuscoguttatus). Among the enzymes tested, Alcalase was the most effective enzyme hydrolysing the by-product of hybrid grouper, followed by Proteinase K, Trypsin, and Pepsin (p < 0.05). According to the results attained, enzyme with the higher degree of hydrolysis exhibited higher antioxidant activities, but not ACE-inhibitory activity. This indicates that the ACEinhibition potency of hydrolysate, from the by-product of hybrid grouper, is very much dependent on the type of enzyme, and the treatment duration during hydrolysis. The ACE-inhibitory activity of Alcalase and Trypsin hydrolysates was found to decrease in tandem with the increase in hydrolysis time. On the other hand, a longer hydrolysis time resulted in a higher ACE-inhibitory activity for Proteinase K and Pepsin hydrolysate (p < 0.05). The results attained suggest that the selection of an appropriate enzyme, together with an effective hydrolysis time, can enhance the bioactivities of the hydrolysate obtained from the by-product of hybrid grouper

ACE-inhibitory and antioxidant activities of hydrolysates from the by-products of hybrid grouper (Epinephelus lanceolatus × Epinephelus fuscoguttatus)

Protein hydrolysates, generated from the by-products of fish, have received much attention over recent years, due to their antihypertensive and antioxidant activities. The potency of bioactive peptides, however, is affected by the type of enzyme selected and the duration of hydrolysis required to generate the protein hydrolysate. This study was aimed to investigate the effects of using four different enzymes (Alcalase, Proteinase K, Trypsin, and Pepsin) and hydrolysis time (1 - 48 h), on the ACE-inhibitory and antioxidant activities (hydroxyl radical scavenging activity and reducing power), of protein hydrolysates from the head and bones of hybrid grouper (Epinephelus lanceolatus × Epinephelus fuscoguttatus). Among the enzymes tested, Alcalase was the most effective enzyme hydrolysing the by-product of hybrid grouper, followed by Proteinase K, Trypsin, and Pepsin (p < 0.05). According to the results attained, enzyme with the higher degree of hydrolysis exhibited higher antioxidant activities, but not ACE-inhibitory activity. This indicates that the ACE-inhibition potency of hydrolysate, from the by-product of hybrid grouper, is very much dependent on the type of enzyme, and the treatment duration during hydrolysis. The ACE-inhibitory activity of Alcalase and Trypsin hydrolysates was found to decrease in tandem with the increase in hydrolysis time. On the other hand, a longer hydrolysis time resulted in a higher ACE-inhibitory activity for Proteinase K and Pepsin hydrolysate (p < 0.05). The results attained suggest that the selection of an appropriate enzyme, together with an effective hydrolysis time, can enhance the bioactivities of the hydrolysate obtained from the by-product of hybrid grouper

Activation of Endothelial Cells by Antiphospholipid Antibodies—A Possible Mechanism Triggering Thrombosis in Patients with Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an antibody-mediated hypercoagulable state characterized by recurrent venous and arterial thromboembolic events. The presence of serum antibodies are collectively termed as antiphospholipid antibodies (aPL) and is the hallmark of the disease. Interest in the pathogenesis has mostly been focused on the blood coagulation factor. However, endothelial cells might play an important role. When stimulated, cell membrane would flip to expose negatively charged phospholipids and activation markers such as adhesive molecules may appear. We consider that these changes may play an important role in the initiation of the thrombotic process when endothelial cells encounter aPL. In this study, we incubated human umbilical vein endothelial cells (HUVECs) with IgG isolated from patients with APS and found that the HUVECs were activated by the expression of negatively charged phospholipids, as shown by high annexin V binding and negative propidium iodide staining and by an increase in the level of intracellular cell adhesion molecule-1 on the cell surface. The above findings indicate that endothelial cells can be activated on exposure to aPL and trigger the thrombotic event

Oxidative stress biomarkers in organs of hyperlipidaemic and natural rats fed tropical red seaweed, Gracilaria changii

The aim of the study was to evaluate the effects of normal and high-cholesterol/fat diet supplemented with 5 and 10% freeze-dried red seaweed, Gracilaria changii powder on rat organs (liver, kidney and heart), lipid peroxidation and antioxidant enzyme activities. The results showed that feeding with atherogenic diet alone caused lipid peroxidation which eventually leads to oxidative stress of the rat’s organs. Nevertheless, with 10 % G. changii supplementation, it significantly decreased the liver lipid peroxidation by 52.24 %, and the antioxidant enzyme activities were significantly increased by 52.09 to 94.42 %. Similarly, with G. changii supplementation, it significantly enhanced the kidney antioxidant enzyme activities. This suggests that G. changii suppress oxidative stress and protect the rats’ organs. In conclusion, G. changii could be a promising functional food ingredient in the management of hyperlipidaemia

Antioxidant activities and polyphenolics of various solvent extracts of red seaweed, Gracilaria changii

This study determined the levels of polyphenols, flavonoids, carotenoids and antioxidant activity of the edible red seaweed, Gracilaria changii. Freeze-dried G. changii powder was extracted using five solvent systems: 80 % ethanol, 80 % methanol, 80 % acetone, ethyl acetate and water. The antioxidant activity of the extracts was measured using three assays, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing power (FRAP) and β-carotene bleaching assays (BCB). The total phenolics (TPC) and total flavonoids content (TFC) and the total carotenoids content (TCC) were also determined. Ethanol extract had the highest yield followed by methanol > water > acetone > ethyl acetate extract. The radical scavenging effects of all the extracts showing dose-dependency properties with the ethyl acetate extract of G. changii exhibiting the highest radical scavenging effect (EC50 of 0.51±0.09 mg mL−1), while the water extract had the lowest scavenging effect of 7.80±0.57 mg mL−1. Ferric reducing power was in the following descending order: ethyl acetate > ethanol > methanol > acetone > water. TPC was highest in the ethyl acetate extract (21.57±2.58 mg PGE g−1) and least in the water extract (6.06±0.52 mg PGE g−1). The TFC of G. changii was in the range of 18.97±0.89–200.87± 3.61 mg RE g−1. The results revealed the effect of different extracting solvents in altering the antioxidant potential of G.changii, and ethyl acetate was identified as the most efficient solvent for extracting bioactive compounds from this red seaweed

Production of ACE-Inhibitory and antioxidant hydrolysates from the fillet of hybrid grouper

Hydrolysates from fish muscle have been reported to exhibit various bioactivities including ACE-inhibitory and antioxidant activities. In this study, the effect of hydrolysis conditions on the ACE-inhibitory and antioxidant activities (hydroxyl radical scavenging activity and reducing power) of hydrolysates from the fillet of hybrid grouper (TGGG) was investigated. The fillet was hydrolysed with four different enzymes (Alcalase, proteinase K, trypsin and pepsin) for 48 hours. Part of the hydrolysates were collected at 1, 2, 4, 6, 24, and 48 hours and analysed for several bioactivities. Results obtained showed that Alcalase and proteinase K hydrolysates demonstrated the highest ACE-inhibitory and hydroxyl radical scavenging activity (p < 0.05). Pepsin hydrolysate on the other hand exhibited the highest reducing power (p < 0.05). Trypsin was the only enzyme where all its bioactivities were affected by the degree of hydrolysis (DH) (p < 0.05). Extensive hydrolysis resulted in a higher hydroxyl radical scavenging of pepsin hydrolysate. The results of this study demonstrated that the proper choice of enzymes and optimal hydrolysis duration could potentially enhance the ACE-inhibitory and antioxidant potency of hydrolysates from the TGGG fillet. Further studies to isolate and identify the potent peptides from the fillet hydrolysate are recommended

Antioxidant and hypolipidaemic properties of red seaweed, Gracilaria changii

The edible red seaweed, Gracilaria changii, was collected from the coastal area of Sarawak, Malaysia, and evaluated for its hypolipidaemic properties using high cholesterol/high fat (HF) induced male Sprague–Dawley rats. In the in vivo study, the HF diet group showed significantly higher total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), atherogenic index (AI) and body weight gain as compared to other treatment groups. At the end of treatment period, rats fed with a HF diet supplemented with 5 % freeze-dried G. changii powder had significantly reduced plasma TC (−39.19 %), LDL-C (−36.36 %), and triglycerides (TG) content (− 25.45 %). Meanwhile, 10 % seaweed powder significantly lowered the plasma TC, LDL-C and TG content by −40.34, −35.95 and −30.91 % respectively, compared to the HF group. The AI of rats supplemented with 10 % seaweed powder was the lowest among the treatment groups and indicates a lowered risk for cardiovascular diseases. The plasma lipid peroxidation of the seaweed powder-fed groups was also significantly lower than the HF group, while the erythrocyte enzyme antioxidant activities of superoxide dismutase, catalase and glutathione peroxidase of the treatment groups were also improved. Diets supplemented with seaweed powder also decreased plasma aspartate aminotransferase and the alanine aminotransferase levels