@article {52, title = {Vitamin D3, L-Arginine, L-Citrulline, and Antioxidant Supplementation Enhances Nitric Oxide Bioavailability and Reduces Oxidative Stress in the Vascular Endothelium {\textendash} Clinical Implications for Cardiovascular System}, journal = {Pharmacognosy Research}, volume = {12}, year = {2020}, month = {February 2020}, pages = {17-23}, type = {Original Article}, chapter = {17}, abstract = {

Background: Nitric oxide (NO) is a crucial signaling molecule which regulates the blood flow and prevents the adhesion of blood components to the vascular wall. A deficiency in bioavailable NO concentration is associated with the dysfunction of endothelial NO synthase (eNOS) and/or an increase in oxidative stress. The deficiency of bioavailable NO is a common denominator of several cardiovascular diseases, including diabetes, atherosclerosis, and hypertension. Materials and Methods: We used a nanomedical technology to elucidate the balance between bioavailable NO and oxidative stress (peroxynitrite ONOO-) in human umbilical vein endothelial cells (HUVECs) treated with a supplement containing L-arginine, L-citrulline, Vitamin D3, and antioxidants. Nanosensors, with a diameter of 200{\textendash}300 nm, are capable of measuring in situ NO and peroxynitrite (ONOO-) concentrations produced by single endothelial cells. Results: The ratio of the concentration of cytoprotective NO [NO] to the concentration of cytotoxic peroxynitrite [ONOO-] was used to estimate the efficiency of eNOS. HUVECs incubated with L-citrulline, L-arginine, and Vitamin D3 increased the [NO]/[ONOO-] ratio by 25\%, while in the presence of antioxidants, the increase was 15\%. The synergistic effect between the mix of L-arginine, L-citrulline, Vitamin D3, and antioxidants was a favorable increase of the overall [NO]/[ONOO-] ratio by 50\%. Conclusion: The findings of the study presented here clearly indicate that L-arginine, L-citrulline, and Vitamin D3 can significantly alter the function of the endothelium and NO production, in a favorable manner, while pointedly reducing ONOO- {\textendash} the main component of oxidative stress. This effect can be significantly potentiated in the presence of antioxidants.

}, keywords = {Antioxidant, Endothelium, L-arginine, L-citrulline, Nitric oxide, Peroxynitrite, Vitamin D3}, doi = {10.4103/pr.pr_79_19}, author = {Hazem Dawoud and Tadeusz Malinski} } @article {393, title = {Analysis of L-citrulline and L-arginine in Ficus deltoidea leaf extracts by reverse phase high performance liquid chromatography}, journal = {Pharmacognosy Research}, volume = {7}, year = {2015}, month = {December 2014}, pages = {32-37}, type = {Original Article}, chapter = {32}, abstract = {

Background:\ Ficus deltoidea (FD) is one of the native plants widely distributed in several countries in Southeast Asia. Previous studies have shown that FD leaf possess antinociceptive, wound healing and antioxidant properties. These beneficial effects have been attributed to the presence of primary and secondary metabolites such as polyphenols, amino acids and flavonoids. Objective: The aim was to develop a reverse phase high-performance liquid chromatography method with ultraviolet detection that involves precolumn derivatisation with O-phthaladehyde for simultaneous analysis of two amino acids L-citrulline and L-arginine in FD leaf extracts. Materials and Methods: An isocratic elution program consisting of methanol: acetonitrile: Water at 45:45:10 v/v (solvent A) and 0.1 M phosphate buffer pH 7.5 (solvent B) at A: B v/v ratio of 80:20 on Zorbax Eclipse C18 SB-Aq column (250 {\texttimes} 4.6 mm, 5 {\textmu}m) were used. The flow rate was set at 1 ml/min and detection was carried out at 338 nm with 30 min separation time. Results: Good linearity for L-citrulline and L-arginine was obtained in the range 0.1-1000 {\textmu}g/ml at R2 >= 0.998. The limit of detection and limit of quantification values for both L-citrulline and L-arginine were 1 and 5 {\textmu}g/ml, respectively. The average of recoveries was in the range 94.94-101.95\%, with relative standard deviation (\%RSD) less than 3\%. Intra- and inter-day precision was in the range 96.36-102.43\% with RSD less than 2\%. Conclusion: All validation parameters of the developed method indicate the method is reliable and efficient for simultaneous determination of L-citrulline and L-arginine for routine analysis of FD.

}, keywords = {Ficus deltoidea, L-arginine, L-citrulline, Reverse phase high-performance liquid chromatography.}, doi = {10.4103/0974-8490.147196}, author = {Armaghan Shafaei and Abdalrahim F. A. Aisha and Mohammad Jamshed Ahmad Siddiqui and Zhari Ismail} }