Zinc dihydrogen di-L-aspartate
[CAS# 36393-20-1]

Identification

• Classification: Biochemical >> Amino acids and their derivatives >> Other amino acid derivatives
• Name: Zinc dihydrogen di-L-aspartate
• Synonyms: L-Aspartic acid zinc salt; Zinc (3S)-3-amino-4-hydroxy-4-oxobutanoate
• Molecular Formula: 2(C₄H₆NO₄).Zn
• Molecular Weight: 329.57
• CAS Registry Number: 36393-20-1
• EC Number: 253-012-5
• SMILES: C([C@@H](C(=O)[O-])N)C(=O)[O-].[Zn+2]

Safety Data

• Hazard Symbols: GHS05;GHS07;GHS09 Danger
• Risk Statements: H302-H315-H318-H319-H411
• Safety Statements: P264-P264+P265-P270-P273-P280-P301+P317-P302+P352-P305+P351+P338-P305+P354+P338-P317-P321-P330-P332+P317-P337+P317-P362+P364-P391-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Serious eye damage	Eye Dam.	1	H318
Acute toxicity	Acute Tox.	4	H302
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Skin irritation	Skin Irrit.	2	H315

Discovery and Applications

Zinc dihydrogen di-L-aspartate is an organometallic coordination compound in which a zinc(II) cation is complexed with two molecules of L-aspartic acid in their dihydrogenated form. The molecular arrangement typically involves the carboxylate groups of the amino acid ligands coordinating to the zinc center, while the amino groups and remaining carboxylic acid protons contribute to hydrogen bonding in the crystalline lattice. This configuration results in a material that combines the nutritional and biochemical roles of both zinc and L-aspartic acid.

The synthesis of zinc dihydrogen di-L-aspartate is usually achieved by reacting zinc oxide, zinc carbonate, or zinc hydroxide with an aqueous solution of L-aspartic acid under controlled pH conditions to ensure selective protonation of the carboxyl groups. The reaction mixture is concentrated and crystallized to yield the pure complex. The choice of reaction parameters, such as ligand-to-metal ratio, pH, and temperature, can influence the crystalline form and hydration state of the product.

As a source of bioavailable zinc, this compound has been investigated for use in dietary supplements and fortified food formulations. Zinc is an essential trace element required for numerous enzymatic systems, immune function, and cellular growth processes. The complexation with L-aspartic acid is believed to enhance zinc absorption in the gastrointestinal tract by taking advantage of amino acid transport mechanisms. This potential for improved bioavailability makes zinc dihydrogen di-L-aspartate of interest in both human and animal nutrition.

In addition to nutritional uses, zinc–amino acid complexes have been explored for their role in mitigating zinc deficiency-related disorders, such as impaired growth, weakened immune response, and skin lesions. The specific complex with L-aspartic acid may also offer better palatability and reduced gastrointestinal irritation compared to some inorganic zinc salts like zinc sulfate.

The compound’s coordination structure also lends it stability in solid form, which facilitates its incorporation into tablets, capsules, and powdered nutritional blends. It is typically stable under normal storage conditions when kept dry and away from excessive heat or light. However, prolonged exposure to moisture can lead to hydrolysis or changes in crystal hydration.

Toxicological considerations align with those for other zinc compounds. While zinc is essential, excessive intake can lead to symptoms of zinc toxicity, including nausea, vomiting, and interference with copper metabolism. Therefore, formulations containing zinc dihydrogen di-L-aspartate must adhere to established dietary intake guidelines.

References

2023. Preliminary Comparison of Fractional Absorption of Zinc Sulphate, Zinc Gluconate, and Zinc Aspartate after Oral Supplementation in Healthy Human Volunteers. Nutrients, 15(8).
DOI: 10.3390/nu15081885

2023. Zinc aspartate induces proliferation of resting and antigen-stimulated human PBMC under high-density cell culture condition. Journal of Trace Elements in Medicine and Biology, 77.
DOI: 10.1016/j.jtemb.2023.127152

2022. Ionic mitigation of CD4+ T cell metabolic fitness, Th1 central nervous system autoimmunity and Th2 asthmatic airway inflammation by therapeutic zinc. Scientific Reports, 12.
DOI: 10.1038/s41598-022-04827-6