Vitamin B3 (
niacin) is also known as pyridine-3-
carboxylic acid, or
nicotinic acid. The name in fact comes from
nicotinic
acid + vitam
in.
There are several derivative compounds e.g.
nicotinamide - the
amide of nicotinic acid (also known as niacinamide).
These can act as a precursor to nicotinamide adenine dinucleotide and its phosphate derivative (often abbreviated as NAD
+/NADH and NADP
+/NADPH), which function as hydrogen and electron acceptors in respiration and photosynthesis.
Dietary deficiency causes
pellagra: cracked, scaly skin, dementia, and diarrhea.
At different (higher) doses, a number of pharmacological effects have been ascribed to niacin (but not the amide): reduction of high cholesterol, atherosclerosis, cataracts.