DL-Thioctic acid
[CAS# 1077-28-7]

Identification

• Classification: Chemical reagent >> Organic reagent >> Fatty acid
• Name: DL-Thioctic acid
• Synonyms: DL-alpha-Lipoic acid; DL-6,8-Dithiooctanoic acid; 5-(Dithiolan-3-yl)valeric acid
• Molecular Formula: C₈H₁₄O₂S₂
• Molecular Weight: 206.32
• CAS Registry Number: 1077-28-7
• EC Number: 214-071-2
• SMILES: C1CSSC1CCCCC(=O)O

Properties

• Solubility: 0.9 g/L (water, 20 °C), 100 mM (DMSO), 100mM (ethanol) (Expl.)
• Density: 1.2±0.1 g/cm³, Calc.^*
• Melting point: 59-63 °C (Expl.)
• Index of Refraction: 1.562, Calc.^*
• Boiling Point: 362.5±11.0 °C (760 mmHg), Calc.^*, 160-165 °C (Expl.)
• Flash Point: 173.0±19.3 °C, Calc.^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07;GHS09 Warning
• Risk Statements: H302-H315-H317-H319-H411
• Safety Statements: P261-P264-P264+P265-P270-P272-P273-P280-P301+P317-P302+P352-P305+P351+P338-P321-P330-P332+P317-P333+P317-P337+P317-P362+P364-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Skin irritation	Skin Irrit.	2	H315
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Skin sensitization	Skin Sens.	1	H317
Eye irritation	Eye Irrit.	2	H319
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H332
Acute toxicity	Acute Tox.	4	H312

Discovery and Applications

DL-Thioctic acid, also known as alpha-lipoic acid, is a naturally occurring compound that plays a crucial role in mitochondrial bioenergetics. It is an organosulfur compound, classified as a fatty acid, with a structure characterized by a cyclic disulfide group. Thioctic acid is synthesized endogenously in the body and functions as a cofactor in several mitochondrial enzyme complexes involved in oxidative decarboxylation reactions.

The discovery of thioctic acid dates back to the 1950s, when it was first identified as a coenzyme in the metabolism of pyruvate and alpha-ketoglutarate, two key intermediates in cellular energy production. It was initially isolated from the livers of animals and later found to be synthesized in trace amounts in human tissues. Thioctic acid is closely related to other coenzymes in cellular energy production, such as coenzyme A and biotin, and its biochemical function is similar to that of B-vitamins.

In terms of application, DL-thioctic acid is widely used in the pharmaceutical and nutraceutical industries. It is primarily known for its potent antioxidant properties. As a lipophilic antioxidant, thioctic acid is able to scavenge free radicals and regenerate other antioxidants, such as vitamins C and E, enhancing the overall antioxidant defense system within cells. Due to its ability to neutralize free radicals, DL-thioctic acid is employed in the management of oxidative stress-related conditions, such as diabetic neuropathy, where it has been shown to improve symptoms by reducing nerve damage caused by oxidative injury.

Thioctic acid has also been studied for its potential therapeutic benefits in a variety of other medical conditions, including cardiovascular diseases, neurodegenerative disorders, and metabolic syndromes. Its role in mitochondrial function, combined with its antioxidant effects, has led to its use in clinical trials exploring its potential as a treatment for conditions associated with mitochondrial dysfunction.

Furthermore, DL-thioctic acid has applications in the food and cosmetic industries due to its antioxidant properties. It is often included in formulations aimed at protecting skin cells from oxidative damage and promoting skin health. In food, it is sometimes used as a supplement to support general health, particularly in relation to mitochondrial energy production and antioxidant defense.

In summary, DL-thioctic acid is a vital compound in cellular metabolism with well-established roles in energy production and antioxidant defense. It has been successfully applied in the treatment of diabetic neuropathy and oxidative stress-related conditions, and continues to be a subject of ongoing research for its potential therapeutic benefits in various health conditions.

References

1995. Lipoic acid metabolism in Escherichia coli: the lplA and lipB genes define redundant pathways for ligation of lipoyl groups to apoprotein. Journal of Bacteriology.
DOI: 10.1128/jb.177.1.1-10.1995

2000. Ascorbate-dependent recycling of the vitamin E homologue Trolox by dihydrolipoate and glutathione in murine skin homogenates. Free Radical Biology and Medicine.
DOI: 10.1016/s0891-5849(00)00309-9

2023. Lipoic Acid Positively Regulates Tomato Growth and Yield by Improving Organic Osmolytes and Antioxidant Defense System Under Saline Conditions. Journal of Soil Science and Plant Nutrition.
DOI: 10.1007/s42729-023-01385-2