Watermelons (Citrullus lanatus) are known to have sufficient amino acid content. In this study, watermelons grown and consumed in Malaysia were investigated for their amino acid content, L-citrulline and L-arginine, by the isocratic RP-HPLC method. Flesh and rind watermelons were juiced, and freeze-dried samples were used for separation and quantification of L-citrulline and L-arginine. Three different mobile phases, 0.7% H3P04, 0.1% H3P04, and 0.7% H3P04 : ACN (90 : 10), were tested on two different columns using Zorbax Eclipse XDB-C18 and Gemini C18 with a flow rate of 0.5 mL/min and a detection wavelength at 195 nm. Efficient separation with reproducible resolution of L-citrulline and L-arginine was achieved using 0.1% H3P04 on the Gemini C18 column. The method was validated and good linearity of L-citrulline and L-arginine was obtained with R2 = 0.9956, y = 0.1664x + 2.4142 and R2 = 0.9912, y = 0.4100x + 3.4850, respectively. L-citrulline content showed the highest concentration in red watermelon of flesh and rind juice extract (43.81 mg/g and 45.02 mg/g), whereas L-arginine concentration was lower than L-citrulline, ranging from 3.39 to 11.14 mg/g. The isocratic RP-HPLC method with 0.1% H3P04 on the Gemini C18 column proved to be efficient for separation and quantification of L-citrulline and L-arginine in watermelons.
Nutritional intervention of fruit juice supplementation is able to maximize exercise performance. Watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai] contains high L-citrulline content and consumption of watermelon juice may promote ergogenic effects. The aim of the present study was to investigate the role of 100% flesh watermelon juice and 100% rind watermelon juice supplementation for 14 days on swimming performance in rats. Twenty four male Sprague-Dawley rats were randomly divided into four groups: Cx group of rats supplemented with filtered tap water (negative control), L-cit group of rats supplemented with L-citrulline (positive control), FR group of rats supplemented with 100% flesh watermelon juice, and RR group of rats supplemented with 100% rind watermelon juice. Each group was supplemented for 14 days ad libitum prior to swimming exercise protocol. The rats were performed swimming exercise for 3 days and swimming time until exhaustion was measured. Plasma samples were collected to measure lactate concentration, ammonia concentration, and nitric oxide production. Rats supplemented with 100% flesh watermelon juice demonstrated significantly prolonged of swimming time until exhaustion, reduction of lactate and ammonia concentrations, and increased of nitric oxide production compared to Cx and L-cit groups (P<0.05). These findings postulate that supplementation with 100% flesh watermelon juice improves endurance in swimming performance.
Watermelon (Citrullus lanatus) is a nutritious fruit that has attracted scientific interest due to its phytonutrient content including carotenoids and amino acids. Watermelon juice is the richest known source of amino acids including L-arginine and L-citrulline. For a complete separation of amino acids in watermelon juices, a gradient mode of reverse phase high performance liquid chromatography (RP-HPLC) with UV detection was utilised owing to its supremacy over isocratic mode. This present study was aimed at achieving good separation of chromatography profiles and baseline between L-arginine and L-citrulline in red and yellow crimson watermelon juice extract. The edible parts of watermelons were juiced, stored at-80 o C and freeze dried to obtain dried juice powder. Samples were analysed by gradient mode of RP-HPLC using 0.1% orthophosphoric acid in water (v/v) and acetonitrile as mobile phase A and B. The chromatograph separation was performed using Gemini C 18 column at a flow rate of 1.0 mL/min, maintained temperature at 25 o C while detection was made at four different wavelengths; 195 nm, 200 nm, 207 nm and 210 nm with total analysis time of 35 min. Excellent chromatographic separation was achieved at conditions of gradient elution (0%B-95%B, 0-18 minutes and 95%B, 18-23 minutes, 95%B-0%B, 23-25 minutes, 0%B, 25-35 minutes) with baseline between L-arginine and L-citrulline in both watermelon juice extracts. The gradient mode used in this RP-HPLC successfully achieved efficient separation of chromatographic profile for amino acids, L-arginine and L-citrulline in the red and yellow crimson watermelon juice extracts.
Engineered nanoparticles have been extensively explored in various biomedical settings including nanoparticulate imaging agents due to its promising benefits to mankind. Iodine-intolerance patients have caused alarming concerns in searching new contrast media with lower toxicity effect. However, proper potential mechanism of nanoparticles has yet to be fully established despite its early acceptance and emerging usage. By using animal model system, our aim is to assess acute toxicity of 14 nm iron oxide nanoparticles (IONPs) coated with citric acid, nitric acid, perchloric acid and silane-polyethylene glycol (SiPEG). Eighteen male Wistar Rats were used in order to explore the underlying toxicity of IONPs in liver tissues after 24 hours. Hydroxyl radicals (˙OH) were elucidated by using reactive oxygen species (ROS) production assay and western blotting for the presence of p53 protein expression. The results revealed SiPEG coated IONPs have lower ROS production and lower expression of p53, however no statistical significant were observed. It can be hypothesized that SiPEG has blood-pooling contrast agent potential due to longer circulation period in blood. While, IONPs not coated with SiPEG tend to be phagocytosed by mononuclear phagocyte system and released Fe2+ ions initiative to acute cellular toxicity. The outcomes highlighted that administration of SiPEG coated IONPs believed to be a safer radiographic contrast media.
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