Vitamins – Vitamin B6 (Pyridoxine) – part 12

Pyridoxine is one of the compounds that can be called vitamin B6, along with pyridoxal and pyridoxamine. It differs from pyridoxamine by the substituent at the ‘4’ position. Its hydrochloride salt pyridoxine hydrochloride is often used.

Pyridoxine
Identifiers
CAS number 65-23-6,
58-56-0 (HCl)
PubChem 1054
ChemSpider 1025 
DrugBank DB00165
KEGG D08454 
ChEBI CHEBI:16709 
ChEMBL CHEMBL1364 
ATC code A11HA02
Jmol-3D images Image 1
Properties
Molecular formula C8H11NO3
Molar mass 169.18 g mol−1
Melting point 159-162 °C

Chemistry

It is based on a pyridine ring, with hydroxyl, methyl, and hydroxymethyl substituents. It is converted to the biologically active form pyridoxal 5-phosphate.

Function in the body

Pyridoxine assists in the balancing of sodium and potassium as well as promoting red blood cell production. It is linked to cardiovascular health by decreasing the formation of homocysteine. Pyridoxine may help balance hormonal changes in women and aid the immune system. Lack of pyridoxine may cause anemia, nerve damage, seizures, skin problems, and sores in the mouth.

It is required for the production of the monoamine neurotransmitters serotonin, dopamine, norepinephrine and epinephrine, as it is the precursor to pyridoxal phosphate: cofactor for the enzyme aromatic amino acid decarboxylase. This enzyme is responsible for converting the precursors 5-hydroxytryptophan (5-HTP) into serotonin and levodopa (L-DOPA) into dopamine, noradrenaline and adrenaline. As such it has been implicated in the treatment of depression and anxiety.

Very good sources of pyridoxine are grains and nuts.

Medicinal uses

Pyridoxine is given to patients taking isoniazid to combat the toxic side effects of the drug. It is given 10–50 mg/day to patients on to prevent peripheral neuropathy and CNS effects that are associated with the use of INH.

It is also essential for patients with extremely rare pyridoxine-dependent epilepsy, thought to be caused by mutations in the ALDH7A1 gene.

In one form of homocystinuria, activity of the deficient enzyme can be enhanced by the administration of large doses of pyridoxine (100-1000 mg/day).

Vitamin B6 can be compounded into a variety of different dosage forms. It can be used orally as a tablet, capsule, or solution. It can also be used as a nasal spray or for injection when in its solution form.

Vitamin B6 is usually safe, at regular intakes up to 200 mg per day in adults. However, vitamin B6 can cause neurological disorders, such as loss of sensation in legs and imbalance, when taken in high doses (200 mg or more per day – 10,000% of US RDA) over a long period of time. Vitamin B6 toxicity can damage sensory nerves, leading to numbness in the hands and feet as well as difficulty walking. Symptoms of a pyridoxine overdose may include poor coordination, staggering, numbness, decreased sensation to touch, temperature, and vibration, and tiredness for up to six months. One study reported that over a 6 month period or longer, 21% of women taking doses greater than 50 mg daily experienced neurological toxicity. The effect of doses below 50 mg was not reported. Pyridoxine’s fetal safety is “A” in Briggs’ Reference Guide to Fetal and Neonatal Risk.

source: http://en.wikipedia.org/wiki/Pyridoxine

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s