Spermidine is apolyamine compound (C 7H 19N 3) originally isolated fromsemen[1] and also found inribosomes and living tissues and has various metabolic functions in organisms.
Spermidine synchronizes an array of biological processes, (such as Ca2+, Na+, K+ -ATPase) thus maintaining membrane potential and controlling intracellular pH and volume. Spermidine regulates biological processes, such as Ca2+ influx by glutamatergicN-methyl-D-aspartate receptor (NMDA receptor), which has been associated withnitric oxide synthase (NOS) and cGMP/PKG pathway activation and a decrease of Na+,K+-ATPase activity in cerebral cortex synaptosomes.
Biosynthesis of spermidine and spermine from putrescine. Ado = 5'-adenosyl.
Spermidine is alongevity agent in mammals due to various mechanisms of action, which are just beginning to be understood.Autophagy is the main mechanism at the molecular level, but evidence has been found for other mechanisms, including inflammation reduction, lipid metabolism, and regulation of cell growth, proliferation, and death.[2][3] Spermidine has been theorized to promote autophagy via theMAPK pathway by inhibiting phosphorylation ofraf,[2] or possibly by inhibiting cytosolicautophagy-related protein acetylation byEP300 and thereby increasing acetylation oftubulin.[3]
Spermidine is known to regulate plant growth, assisting thein vitro process of transcribing RNA, and inhibition of NOS. Also, spermidine is a precursor to other polyamines, such as spermine and thermospermine, some of which contribute to tolerance againstdrought andsalinity in plants.
Spermidine has been tested and discovered to encourage hair shaft elongation and lengthen hair growth. Spermidine has also been found to "upregulate expression of the epithelial stem cell-associated keratins K15 and K19, and dose-dependently modulated K15 promoter activityin situ and the colony forming efficiency, proliferation and K15 expression of isolated human K15-GFP+ cellsin vitro."[4]
Good dietary sources of spermidine are aged cheese, mushrooms, soy products, legumes, corn, and whole grains.[14] Spermidine is plentiful in aMediterranean diet.[3]For comparison: The spermidine content in human seminal plasma varies between approx. 15 and 50 mg/L (mean 31 mg/L).[15]
Note: spermidine content varies by source and age. See ref for details.
In grains, theendosperm contains most of the spermidine. One of the best known grain dietary sources iswheat germ, containing as much as 243 mg/kg.[16]
Spermidine can be used inelectroporation while transferring the DNA into the cell under the electrical impulse. May be used for purification of DNA-binding proteins.
Spermidine is also used, along with calcium chloride, for precipitating DNA onto microprojectiles for bombardment with agene gun.[17]
Spermidine has also been reported to protect the heart from aging and prolong the lifespan of mice, while in humans it was correlated with lower blood pressure.[18] It also was found to reduce the amount of aging in yeast, flies, worms, and human immune cells by inducingautophagy.[19]
Spermidine may play a role in male and female fertility.[medical citation needed] Fertile men have higher spermidine levels than men who are infertile,[20] and spermidine supplementation has been shown to help maintain a healthy hormone balance and reduce oxidative stress.[21]
Spermidine is commonly used for in vitro molecular biology reactions, particularly, in vitro transcription by phage RNA polymerases,[22]in vitro transcription by human RNA polymerase II,[23] andin vitro translation.
Spermidine increases specificity and reproducibility of Taq-mediated PCR by neutralizing and stabilizing the negative charge on DNA phosphate backbone.
^abMinois N (28 January 2014). "Molecular Basis of the 'Anti-Aging' Effect of Spermidine and Other Natural Polyamines – A Mini-Review".Gerontology.60 (4):319–326.doi:10.1159/000356748.PMID24481223.
^Bouché JP (1981). "The effect of spermidine on endonuclease inhibition by agarose contaminants".Analytical Biochemistry.115 (1):42–5.doi:10.1016/0003-2697(81)90519-4.PMID6272602.
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