2744
T3D2702
(R)-lipoic acid
Lipoic acid is a vitamin-like antioxidant that acts as a free-radical scavenger. Alpha-lipoic acid is also known as thioctic acid. It is a naturally occurring compound that is synthesized by both plants and animals. Lipoic acid contains two thiol groups which may be either oxidized or reduced. The reduced form is known as dihydrolipoic acid (DHLA). Lipoic acid (Delta E= -0.288) is therefore capable of thiol-disulfide exchange, giving it antioxidant activity. Lipoate is a critical cofactor for aerobic metabolism, participating in the transfer of acyl or methylamine groups via the 2-Oxoacid dehydrogenase (2-OADH) or alpha-ketoglutarate dehydrogenase complex. This enzyme catalyzes the conversion of alpha-ketoglutarate to succinyl CoA. This activity results in the catabolism of the branched chain amino acids (leucine, isoleucine and valine). Lipoic acid also participates in the glycine cleavage system(GCV). The glycine cleavage system is a multi-enzyme complex that catalyzes the oxidation of glycine to form 5,10 methylene tetrahydrofolate, an important cofactor in nucleic acid synthesis. Since Lipoic acid is an essential cofactor for many enzyme complexes, it is essential for aerobic life as we know it. This system is used by many organisms and plays a crucial role in the photosynthetic carbon cycle. Lipoic acid was first postulated to be an effective antioxidant when it was found it prevented vitamin C and vitamin E deficiency. It is able to scavenge reactive oxygen species and reduce other metabolites, such as glutathione or vitamins, maintaining a healthy cellular redox state. Lipoic acid has been shown in cell culture experiments to increase cellular uptake of glucose by recruiting the glucose transporter GLUT4 to the cell membrane, suggesting its use in diabetes. Studies of rat aging have suggested that the use of L-carnitine and lipoic acid results in improved memory performance and delayed structural mitochondrial decay. As a result, it may be helpful for people with Alzheimer's disease or Parkinson's disease.
62-46-4
6112
C8H14O2S2
206.043520
White powder.
60.5°C
162.5°C
Insoluble
(R)-lipoic acid is a cholinesterase or acetylcholinesterase (AChE) inhibitor. A cholinesterase inhibitor (or 'anticholinesterase') suppresses the action of acetylcholinesterase. Because of its essential function, chemicals that interfere with the action of acetylcholinesterase are potent neurotoxins, causing excessive salivation and eye-watering in low doses, followed by muscle spasms and ultimately death. Nerve gases and many substances used in insecticides have been shown to act by binding a serine in the active site of acetylcholine esterase, inhibiting the enzyme completely. Acetylcholine esterase breaks down the neurotransmitter acetylcholine, which is released at nerve and muscle junctions, in order to allow the muscle or organ to relax. The result of acetylcholine esterase inhibition is that acetylcholine builds up and continues to act so that any nerve impulses are continually transmitted and muscle contractions do not stop. Among the most common acetylcholinesterase inhibitors are phosphorus-based compounds, which are designed to bind to the active site of the enzyme. The structural requirements are a phosphorus atom bearing two lipophilic groups, a leaving group (such as a halide or thiocyanate), and a terminal oxygen.
Paraoxonase (PON1) is a key enzyme in the metabolism of organophosphates. PON1 can inactivate some organophosphates through hydrolysis. PON1 hydrolyzes the active metabolites in several organophosphates insecticides as well as, nerve agents such as soman, sarin, and VX. The presence of PON1 polymorphisms causes there to be different enzyme levels and catalytic efficiency of this esterase, which in turn suggests that different individuals may be more susceptible to the toxic effect of OP exposure.
No indication of carcinogenicity to humans (not listed by IARC).
For nutritional supplementation, also for treating dietary shortage or imbalance.
Acute exposure to cholinesterase inhibitors can cause a cholinergic crisis characterized by severe nausea/vomiting, salivation, sweating, bradycardia, hypotension, collapse, and convulsions. Increasing muscle weakness is a possibility and may result in death if respiratory muscles are involved. Accumulation of ACh at motor nerves causes overstimulation of nicotinic expression at the neuromuscular junction. When this occurs symptoms such as muscle weakness, fatigue, muscle cramps, fasciculation, and paralysis can be seen. When there is an accumulation of ACh at autonomic ganglia this causes overstimulation of nicotinic expression in the sympathetic system. Symptoms associated with this are hypertension, and hypoglycemia. Overstimulation of nicotinic acetylcholine receptors in the central nervous system, due to accumulation of ACh, results in anxiety, headache, convulsions, ataxia, depression of respiration and circulation, tremor, general weakness, and potentially coma. When there is expression of muscarinic overstimulation due to excess acetylcholine at muscarinic acetylcholine receptors symptoms of visual disturbances, tightness in chest, wheezing due to bronchoconstriction, increased bronchial secretions, increased salivation, lacrimation, sweating, peristalsis, and urination can occur. Certain reproductive effects in fertility, growth, and development for males and females have been linked specifically to organophosphate pesticide exposure. Most of the research on reproductive effects has been conducted on farmers working with pesticides and insecticdes in rural areas. In females menstrual cycle disturbances, longer pregnancies, spontaneous abortions, stillbirths, and some developmental effects in offspring have been linked to organophosphate pesticide exposure. Prenatal exposure has been linked to impaired fetal growth and development. Neurotoxic effects have also been linked to poisoning with OP pesticides causing four neurotoxic effects in humans: cholinergic syndrome, intermediate syndrome, organophosphate-induced delayed polyneuropathy (OPIDP), and chronic organophosphate-induced neuropsychiatric disorder (COPIND). These syndromes result after acute and chronic exposure to OP pesticides.
Symptoms of low dose exposure include excessive salivation and eye-watering. Acute dose symptoms include severe nausea/vomiting, salivation, sweating, bradycardia, hypotension, collapse, and convulsions. Increasing muscle weakness is a possibility and may result in death if respiratory muscles are involved. Hypertension, hypoglycemia, anxiety, headache, tremor and ataxia may also result.
If the compound has been ingested, rapid gastric lavage should be performed using 5% sodium bicarbonate. For skin contact, the skin should be washed with soap and water. If the compound has entered the eyes, they should be washed with large quantities of isotonic saline or water. In serious cases, atropine and/or pralidoxime should be administered. Anti-cholinergic drugs work to counteract the effects of excess acetylcholine and reactivate AChE. Atropine can be used as an antidote in conjunction with pralidoxime or other pyridinium oximes (such as trimedoxime or obidoxime), though the use of '-oximes' has been found to be of no benefit, or possibly harmful, in at least two meta-analyses. Atropine is a muscarinic antagonist, and thus blocks the action of acetylcholine peripherally.
2009-07-21T20:26:12Z
2014-12-24T20:25:49Z
Lipoic_Acid
C00725
16494
LIPOIC-ACID
Lipoic Acid
DB00166
LPA
true
OC(=O)CCCCC1CCSS1
C8H14O2S2
InChI=1/C8H14O2S2/c9-8(10)4-2-1-3-7-5-6-11-12-7/h7H,1-6H2,(H,9,10)
InChIKey=AGBQKNBQESQNJD-UHFFFAOYNA-N
206.326
206.043521072
Endogenous
Solid
2.1
HMDB01451
CHEMBL134342
5886
<p>Joachim Paust, Peter Eckes, Wolfgang Siegel, Friedhelm Balkenhohl, Walter Dobler, Michael Hullmann, “Preparation of R/S-.gamma.-lipoic acid or R/S-.alpha.-lipoic acid.” U.S. Patent US5489694, issued July, 1961.</p>