Mechanism of Action
1) Mecobalamin is a kind of endogenous coenzyme B12
Mecobalamin plays an important role in transmethylation as a coenzyme of methionine synthetase in the synthesis of methionine from homocysteine.
2) Mecobalamin is well transported to nerve cell organelles and promotes nucleic acid and protein synthesis.
Mecobalamin is better transported to nerve cell organelles than cyanocobalamin in rats. It has been shown in experiments with cells from the brain origin and spinal nerve cells in rats to be involved in the synthesis of thymidine from deoxyuridine, promotion of deposited folic acid utilization and metabolism of nucleic acid. Also, mecobalamin promotes nucleic acid and protein synthesis in rats more than cobamamide does.
3) Mecobalamin promotes axonal transport and axonal regeneration.
Mecobalamin normalizes axonal skeletal protein transport in sciatic nerve cells from rat models with streptozotocin-induced diabetes mellitus. It exhibits neuropathologically and electrophysiologically inhibitory effects on nerve degeneration neuropathies induced by drugs, such as adriamycin, acrylamide, and vincristine (in rats and rabbits), models of axonal degeneration in mice and neuropathies in rats with spontaneous diabetes mellitus.
4) Mecobalamin promotes myelination (phospholipid synthesis)
Mecobalamin promotes the synthesis of lecithin, the main constituent of medullary sheath lipid and increases myelination of neurons in rat tissue culture more than cobamamide does.
5) Mecobalamin restores delayed synaptic transmission and diminished neurotransmitters to normal.
Mecobalamin restores end-plate potential induction early by increasing nerve fiber excitability in the crushed sciatic nerve in rats. In addition, mecobalamin normalizes diminished brain tissue levels of acetylcholine in rats fed a choline-deficient diet.
Clinical Studies
Clinical efficacy
Mecobalamin was administered orally to patients with peripheral neuropathies at doses of 1 ,500 and 120 mcg (low-dose group) daily divided into three doses for 4 consecutive weeks in a double-blind clinical trial. In the chronic stage and fixed stage in peripheral neuropathies, the improvement rate for moderately to remarkably improved was 17.6% (6/34) in 1,500 mcg group and 9.7% (3/31) I in 120 mcg group. The improvement rate for fairly to remarkably improved was 64.7% (22/34) in the 1,500 mcg group and 41.9% (13/31) in the 120 mcg group. The dose of 1,500 mcg/day was thus demonstrated to be useful.
In a placebo-controlled double blind clinical trial, mecobalamin and cobamamide were administered orally to patients with peripheral neuropathies at doses of 1,500 mcg daily for 4 consecutive weeks. The rates for moderately to remarkably improved for peripheral neuropathies were 38.6% (17/44) for mecobalamin, 22.2% (10/45) for cobamamide and 26.7% (12/45) for placebo. Mecobalamin was thus demonstrated to be useful.