Quantitative analysis and Hepatoprotective effects of L-Ornithine L-aspartate salt

L-Ornithine L-aspartate salt was developed in Germany in the 1960s and was initially used clinically for the treatment of alcohol intoxication and hepatic encephalopathy. L-Ornithine L-aspartate salt is composed of two naturally occurring, non-essential L-amino acids—ornithine and aspartate—and exhibits oral activity. L-Ornithine L-aspartate effectively reduces blood ammonia levels and alleviates symptoms associated with hepatic encephalopathy related to cirrhosis. Additionally, L-Ornithine L-aspartate improves mitochondrial function. The compound has gained broader application in the treatment of liver diseases, demonstrating proven efficacy in conditions such as hepatic encephalopathy, drug-induced liver injury, fatty liver disease, and chronic hepatitis. Consequently, L-Ornithine L-aspartate has received widespread recognition from clinicians.

Figure1: Picture of L-Ornithine L-aspartate salt

Overview

L-Ornithine L-aspartate salt is a compound composed of two endogenous amino acids, L-ornithine and L-aspartate. L-Ornithine L-aspartate salt is well recognized for its efficacy in lowering blood ammonia levels, and consequently, L-Ornithine L-aspartate salt plays a key role in the management of hepatic encephalopathy (HE). The established effects of L-Ornithine L-aspartate salt include stimulating hepatic urea synthesis, enhancing glutamine production in muscle tissue, and modulating the balance between branched-chain and aromatic amino acids. L-Ornithine L-aspartate salt supplies essential substrates to the metabolic pathways responsible for ammonia detoxification. Specifically, ornithine activates carbamoyl phosphate synthetase, while aspartate contributes nitrogen to stimulate arginase activity, both enzymes being critical for urea synthesis. Administration of L-Ornithine L-aspartate salt reduces plasma ammonia levels and elevates plasma urea concentrations, thereby demonstrating its capacity to enhance the activity of the Krebs cycle. Beyond its established function as an ammonia scavenger, emerging evidence indicates that L-Ornithine L-aspartate salt exerts a direct hepatoprotective effect. In patients with fatty liver disease, L-Ornithine L-aspartate salt has been shown to attenuate elevated serum levels of liver enzymes. Furthermore, L-Ornithine L-aspartate salt helps maintain the oxidant-antioxidant balance within hepatocytes by supplying L-ornithine and L-aspartate as precursors for glutamate synthesis. The glutamate generated from L-Ornithine L-aspartate salt metabolism is subsequently utilized to produce glutathione (GSH), a potent antioxidant essential for mitigating oxidative damage. [1]

Quantitative analysis

A simple yet accurate spectrophotometric technique was developed and employed to determine the levels of L-Ornithine L-aspartate salt in both its pure form and commercial dosage formulations. The method involves the oxidation of L-Ornithine L-aspartate salt using alkaline potassium permanganate at room temperature (30 ± 2 °C). The progress of the reaction was monitored spectrophotometrically by measuring the increase in absorbance at 610 nm. Calibration curves were constructed using both the initial rate method and the fixed-time method (with a ten-minute reaction period). L-Ornithine L-aspartate salt analysis was validated according to ICH guidelines for linearity, precision, accuracy, and reproducibility, with experimental variables optimized accordingly. L-Ornithine L-aspartate salt exhibited excellent linearity across the concentration range of 5–60 µg/mL, adhering to Beer's law. The regression equation for the initial rate method was log A = 2.566 + 0.988 log C, while for the fixed-time method it was A = −3.34 × 10⁻² + 0.02833 C. The proposed method was successfully applied for the accurate quantification of L-Ornithine L-aspartate salt in commercial dosage forms, demonstrating its suitability for routine quality control analysis. [1]

Hepatoprotective effects

L-Ornithine L-aspartate salt improves hepatocyte morphology and inhibits markers of liver injury in CCl₄-induced hepatitis. Seven days after toxic liver injury induced by CCl₄, the hepatic lobular structure was markedly disrupted. Central veins appeared slightly dilated and devoid of erythrocytes. The trabecular architecture was only partially preserved, and sinusoidal lumens were detectable only in regions containing macrophages. Throughout the lobule, hepatocyte cytoplasm exhibited expansion, leading to an increased cytoplasmic area and reduced sinusoidal spaces. Slightly hyperchromic nuclei were observed in most cells, while intercellular contacts remained only partially intact. Moderate lympho-histiocytic infiltration was evident in the portal tracts. Following treatment, L-Ornithine L-aspartate salt promoted progressive restoration of liver structure. Central veins were no longer distinctly visualized. The trabecular organization of hepatocytes was largely reestablished, with sinusoidal lumens observable across the entire lobule. In some areas, sinusoids were moderately dilated and contained sparse erythrocytes along with occasional macrophages. Hepatocyte size decreased, cytoplasm became more homogeneous, dystrophic features diminished, nuclei normalized, and intercellular contacts were restored. An increased number of binuclear hepatocytes was noted. Within the portal tracts, mild and predominantly focal lympho-histiocytic infiltration persisted. [2]

Reference

[1] Rubel Mondal D A S. Development and Validation of Spectroscopic Method for Determination of L-Ornithine L-Aspartate in Commercial Dosage Form[J]. Journal of Medical and Clinical Case Reports, 2: 6.

[2] Oleshchuk O M, Datsko V A, Loi H Y, et al. Hepatoprotective effects of L-ornithine-L-aspartate in toxic liver injury[J]. Pharmacology Online, 2021, 3: 146-155.

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