Allantoin

Allantoin is a skin conditioning agent that promotes healthy skin, stimulates new and healthy tissue growth.

In Vitro:Allantoin is a well-known cosmetic ingredient reported to have anti-oxidative and anti-inflammatory activities[1]. Allantoin attenuates apoptosis and cytotoxicity and increased the viability of STZ-induced β-cells in a dose-dependent manner. Allantoin decreases the level of caspase-3 and increases the level of phosphorylated B-cell lymphoma 2 (Bcl-2) expression. Allantoin has been demonstrated to activate imidazoline 3 (I3) receptors[2].

In Vivo:The subchronic administration of allantoin (1, 3 or 10 mg/kg, for 7 days) significantly increases the latency time measured during the passive avoidance task in scopolamine-induced cholinergic blockade and normal naive mice. Allantoin treatment (3 or 10 mg/kg, for 7 days) also increases the expression levels of phosphorylated phosphatidylinositide 3-kinase (PI3K), phosphorylated protein kinase B (Akt) and phosphorylated glycogen synthase kinase-3β (GSK-3β). Allantoin significantly increases the neuronal cell proliferation of immature neurons in the hippocampal dentate gyrus region[1]. Daily injection of allantoin for 8 days in STZ-treated rats significantly lowers plasma glucose and increases plasma insulin levels [2]. Allantoin decreases blood pressures in SHRs at 30 minutes, as the most effective time. Also, this antihypertensive action is shown in a dose-dependent manner from SHRs treated with allantoin. Moreover, in anesthetized rats, allantoin inhibits cardiac contractility and heart rate. Also, the peripheral blood flow is markedly increased by allantoin[3].

References:
[1]. Ahn YJ, et al. Effects of allantoin on cognitive function and hippocampal neurogenesis. Food Chem Toxicol. 2014 Feb;64:210-6. [2]. Amitani M, et al. Allantoin ameliorates chemically-induced pancreatic β-cell damage through activation of the imidazoline I3 receptors. PeerJ. 2015 Aug 6;3:e1105. [3]. Chen MF, et al. Antihypertensive action of allantoin in animals. Biomed Res Int. 2014;2014:690135.

The purine metabolite allantoin enhances abiotic stress tolerance through synergistic activation of abscisic acid metabolism.[Pubmed:24182190]

Plant Cell Environ. 2014 Apr;37(4):1022-36.

Purine catabolism is regarded as a housekeeping function that remobilizes nitrogen for plant growth and development. However, emerging evidence suggests that certain purine metabolites might contribute to stress protection of plants. Here, we show that in Arabidopsis, the intermediary metabolite Allantoin plays a role in abiotic stress tolerance via activation of abscisic acid (ABA) metabolism. The aln loss-of-function of ALN, encoding Allantoinase, results in increased Allantoin accumulation, genome-wide up-regulation of stress-related genes and enhanced tolerance to drought-shock and osmotic stress in aln mutant seedlings. This phenotype is not caused by a general response to purine catabolism inhibition, but rather results from a specific effect of Allantoin. Allantoin activates ABA production both through increased transcription of NCED3, encoding a key enzyme in ABA biosynthesis, and through post-translational activation via high-molecular-weight complex formation of BG1, a beta-glucosidase hydrolysing glucose-conjugated ABA. Exogenous application of Allantoin to wild-type plants also activates the two ABA-producing pathways that lead to ABA accumulation and stress-responsive gene expression, but this effect is abrogated in ABA-deficient and BG1-knockout mutants. We propose that purine catabolism functions not only in nitrogen metabolism, but also in stress tolerance by influencing ABA production, which is mediated by the possible regulatory action of Allantoin.

Antihypertensive action of allantoin in animals.[Pubmed:24745022]

Biomed Res Int. 2014;2014:690135.

The agonists of imidazoline I-1 receptors (I-1R) are widely used to lower blood pressure. It has been indicated that guanidinium derivatives show an ability to activate imidazoline receptors. Also, Allantoin has a chemical stricture similar to guanidinium derivatives. Thus, it is of special interest to characterize the effect of Allantoin on I-1R. In conscious male spontaneous hypertensive rats (SHRs), mean blood pressure (MBP) was recorded using the tail-cuff method. Furthermore, the hemodynamic analyses in catheterized rats were applied to measure the actions of Allantoin in vivo. Allantoin decreased blood pressures in SHRs at 30 minutes, as the most effective time. Also, this antihypertensive action was shown in a dose-dependent manner from SHRs treated with Allantoin. Moreover, in anesthetized rats, Allantoin inhibited cardiac contractility and heart rate as showing in hemodynamic dP/dt max significantly. Also, the peripheral blood flow was markedly increased by Allantoin. Both actions were diminished by efaroxan at the dose sufficient to block I-1R. Thus, we suggest that Allantoin, as I-1R agonist, has the potential to develop as a new therapeutic agent for hypertension in the future.

Solid lipid nanoparticles containing copaiba oil and allantoin: development and role of nanoencapsulation on the antifungal activity.[Pubmed:25980176]

Pharmazie. 2015 Mar;70(3):155-64.

The aim of this work was to develop solid lipid nanoparticles (SLN) containing copaiba oil with and without Allantoin (NCOA, NCO, respectively) and to evaluate their antifungal activity. Nanoparticle suspensions were prepared using a high homogenisation technique and characterised by dynamic light scattering, laser diffraction, nanoparticle tracking analysis, multiple light scattering analysis, high-pressure liquid chromatography, pH and rheology. The antifungal activities of the formulations were tested in vitro against the emergent yeasts Candida krusei and Candida parapsilosis, and the fungal pathogens of human skin Trichophyton rubrum and Microsporum canis. The dynamic light scattering analysis showed z-average diameters (intensity) between 118.63 +/- 8.89 nm for the nanoparticles with both copaiba oil and Allantoin and 126.06 +/- 9.84nm for the nanoparticles with just copaiba oil. The D[4,3] determined by laser diffraction showed similar results of 123 +/- 1.73 nm for the nanoparticles with copaiba oil and Allantoin and 130 +/- 3.6 nm for the nanoparticles with copaiba oil alone. Nanoparticle tracking analysis demonstrated that both suspensions had monomodal profiles and consequently, the nanoparticle populations were homogeneous. This analysis also corroborated the results of dynamic light scattering and laser diffraction, exhibiting a smaller mean diameter for the nanoparticles with copaiba oil and Allantoin (143 nm) than for the nanoparticles with copaiba oil (204 nm). The physicochemical properties indicated that the dispersions were stable overtime. Rheology evidenced Newtonian behaviour for both suspensions. Antifungal susceptibility showed a MIC90 of 125 mug/mL (nanoparticles with copaiba oil) and 7.8 mug/mL (nanoparticles with copaiba oil and Allantoin) against C. parapsilosis. The nanoparticles with copaiba oil and the nanoparticles with copaiba oil and Allantoin presented a MIC90 of 500 mug/mL and 250 mug/mL, respectively, against C. krusei. The MIC90 values were 500 mug/mL (nanoparticles with copaiba oil) and 1.95 mug/mL (nanoparticles with copaiba oil and Allantoin) against T. rubrum. Against M. canis, the nanoparticles with copaiba oil and Allantoin had a MIC9 of 1.95 mug/mL. In conclusion, nanoencapsulation improved the antifungal activity of copaiba oil, which was enhanced by the presence of Allantoin. The MICs obtained are comparable to those of commercial products and can represent promising therapeutics for cutaneous infections caused by yeasts and dermatophytes.

Effects of allantoin on cognitive function and hippocampal neurogenesis.[Pubmed:24296131]

Food Chem Toxicol. 2014 Feb;64:210-6.

Allantoin is contained in Nelumbo nucifera (lotus) and a well-known cosmetic ingredient reported to have anti-oxidative and anti-inflammatory activities. In the present study, we investigated whether Allantoin affects cognitive function in mice. The subchronic administration of Allantoin (1, 3 or 10 mg/kg, for 7 days) significantly increased the latency time measured during the passive avoidance task in scopolamine-induced cholinergic blockade and normal naive mice. Allantoin treatment (3 or 10 mg/kg, for 7 days) also increased the expression levels of phosphorylated phosphatidylinositide 3-kinase (PI3K), phosphorylated protein kinase B (Akt) and phosphorylated glycogen synthase kinase-3beta (GSK-3beta). Doublecortin and 5-bromo-2-deoxyuridine immunostaining revealed that Allantoin significantly increased the neuronal cell proliferation of immature neurons in the hippocampal dentate gyrus region. In conclusion, Allantoin has memory-enhancing effects, and these effects may be partly mediated by the PI3K-Akt-GSK-3beta signal pathway. These findings suggest that Allantoin has therapeutic potential for the cognitive dysfunctions observed in Alzheimer's disease.