The objective of this study was to determine the antioxidant activity of Rhodomyrtus tomentosa fruit extract and its effect on triacylglycerides (TG), total cholesterol (TC), low density lipoprotein (LDL), high density lipoprotein (HDL) and lipid peroxidation in induced-cholesterol New Zealand White Rabbits. In DPPH assay, at concentration of 200 ug/mL methanol extract give 62.13% inhibition of DPPH free radicals with IC50 of 107 μg/mL. Similarly, in FRAP assay the methanol extract at concentration of 500 ug/mL showed the highest absorbance (0.16) for antioxidant activity. Whereas, in metal chelating assay the methanol extract at concentration of 100 mg/mL exhibited 36% inhibition of metal chelating ions. The antioxidant activities were due to the presence of phenolics compounds of quinic acid, gallic acid and caffeic acid, which were identified with Q-TQF MS. Total phenolic and total flavonoid content was the highest in water extract at 66.515 mg of GAE/g and 1.828 mg of QE/g, respectively. The water extract of R. tomentosa was non-toxic at LC50 = 616.083 μg/mL. The white New Zealand rabbits group A was fed by oral gavages with normal diet; Group B cholesterol 1% diet; group C cholesterol 1% diet with fruit extract 50 mg/kg and Group D cholesterol 1% diet with simvastatin standard drug 5 mg/kg. The rabbits in group C has a significantly reduced (p<0.05) total cholesterol (TC), low density lipoprotein (LDL) and significantly increased (p<0.05) high density lipoprotein (HDL) and triacylglycerides (TG) as compared with group B. The lipid peroxidation was reduced significantly (p<0.05) as indicated by the low TBARs-MDA level in group C. Thus, these results showed that the R. tomentosa fruit extracts was able to reduce cholesterol level and increased HDL level which can prevent the formation of atherosclerosis in New Zealand white rabbits.

Background: Prawns and shrimp are a frequent cause of seafood allergy mediated by IgE antibodies. Penaeus monodon and Penaeus latisulcatus, commonly known as black tiger prawn and king prawn, respectively, are among the most frequently consumed prawns in Malaysia. The aim of this study was to identify the IgE-binding proteins of these 2 prawn species. Methods: Raw and boiled prawn extracts were prepared and then resolved by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). IgE-immunoblotting was then performed using sera from patients with positive skin prick tests to the raw prawn extracts. Results: SDS-PAGE analysis of the raw extracts of both prawn species revealed 23 protein bands; the boiled extracts yielded fewer protein bands. The bands in the range of 40 to 100 kDa were sensitive to heat and therefore were not found in the boiled extracts. Immunoblot of raw extracts of black tiger prawns and king prawns yielded 14 and 11 IgE-binding proteins, respectively, with molecular weights of between 15 and 200 kDa. Proteins at 36, 42, and 49 kDa were detected as the major allergens in both species of prawns. A protein of 75 kDa was also identified as a major allergen in black tiger prawns. Other potential allergens were also observed at various molecular masses. Conclusion: Proteins of 36, 42, and 49 kDa were identified as the major allergens of both species of prawns. The 36 and 42 kDa proteins are hypothesised to be tropomyosin and arginine kinase, respectively. A high molecular weight protein of 75 kDa was found to be an additional major allergen in black tiger prawns.