Journal of Aging Science

A Mini Review of Astaxhantin and Oxidative Stress in Aging

Gülsüm Deveci^* and Nilüfer Acar Tek Department of Nutrition and Dietetics, Gazi University, Ankara, Turkey
^*Correspondence: Gülsüm Deveci, Department of Nutrition and Dietetics, Faculty of Health Sciences, Gazi University, Turkey,

Received: 09-Sep-2019 Published: 01-Oct-2019

Introduction

Free radicals, wear and tear, destructive DNA damage, mechanism loss of mitochondria, cellular adaptation and stochastic theories are some of over 300 theories about the aging process [1-4]. With regard to these theories, exogenous factors, such as lifestyle, stress, contribute to aging process, in addition to some metals and naturally occurring free radicals in cells and tissues [1,5].

Lots of agents such as hormones, body proteins and immune system cells also change with age as a result of diversity in gene expression [1]. Diminished physiological function leads defense system up against oxidation and other biochemical variance to fall into a decline and cell survival to become shorter [6].The other reason for oxidative stress increasing with age is decreased intake of exogenous antioxidants from nutrition [7].

Utilization of nutritional supplements against inadequacies due to nutritional diversification seen in the elderly lessens the adverse effects of senescence on immune functions [8]. Antioxidants such as ascorbic acid, phenolic compounds, sterols and carotenoids, which are indigenous to foods, decrease oxidative damage to a minimum level or/and prevent it altogether [9,10].

Various carotenoids, pigments derived from organic hydrocarbons, not only induce antioxidant activity but also have positive effects on glutathione and activation of enzymes such as cyclooxygenase, SOD and caspase-3 and -9 [11-15].There are two subunits of carotenoids in terms of oxygen atom-inclusiveness, carotenes, and xanthophyll’s [11]. Astaxhantin (ASTX) is an oxidized carotenoid derivative, including both hydroxy and oxy groups [16].

Additionally, double band and polar-apolar-polar structure help differentiate ASTX from other xanthophyll’s and contribute to greater antioxidant activation [17]. Other properties that make ASTX special include indicating vitamin A activity in due course of metabolized in liver, permeant through blood-brain barrier and partaking in grey matter of brain [18,19].

Abdelzaher et al. suggested that ASTX inhibits reactive oxygen species [20]. They stated that incubation of 25 μM ASTX in cellculture for 24 hours reduces accumulation of free radicals in cells [21]. In another study, individuals aged 20-55 years who consumed 20 mg ASTX for 12 weeks experienced decreased serum malondialdehyde levels, an indicator of oxidation [22]. Astaxhantin administrations in various doses in rats and humans (20 mg/kg/day in rats; 5 mg/day, 20 mg/day, 40 mg/day in humans) provide superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) with activation and enhance total antioxidant capacity [23-25].

Baralic et al. seeking to understand the effect of ASTX on oxidative stress in humans has shown that subjects given 4 mg ASTX for 90 days had increased paraoxonase-1 activity, an antioxidant enzyme [26]. In this article, because of the unique properties of ASTX that distinguish it from other carotenoids, and because it is high in antioxidants, we investigated impacts of ASTX on oxidative stress dependent on senescence, and is tackled that it may be protective against oxidative stress.

Materials and Methods

Properties of Astaxhantin

Hydroxy (OH-) groups in both two terminal ends of ASTX make polar characteristic available to its pattern while middle part is also nonpolar [27]. Chemical structures of ASTX and its metabolites were shown in Figure 1 [28].

Figure 1. Chemical structures of ASTX and its metabolite.

There are several isomers subject to configuration of OH- groups [17]. Natural ASTX is esterified and artificial ASTX is free form [29]. Astaxhantin stereoisomers are classified by their OHgroups. Astaxhantin isomers are Enantiomer (3S, 3’S), Enantiomer (3R, 3’R), and Mesomere (3R, 3’S) that are identified for C-3 and C-3’ carbon atoms in chiral-cores. Of these isomers, enantiomer (3S, 3’S) is the dominant form of ASTX (Figure 2) [30,31].

Figure 2. Chemical structures of ASTX isomers.

Once consumed, astaxhantin is first absorbedviapassive diffusion by enterocytes, and is got undergone via facilitated diffusion in the presence of lipids [29]. Its non-esterified form is brought in through chylomicrons to the liver. Then, this form is transported by lipoprotein to other tissues [32]. More than 50% of ASTX taken within 24 hours is metabolized. The main metabolic afterproduct is 3-hydroxy-4-oxo-β-ionone. Afterwards, this last product conjugates to 3-hydroxy-4-oxo-7,8-dihydro-β- ionone (Figure 1) [28,33]. Basic sources of ASTX are phytoplankton and Haematococcus pluvialis H. (pluvalis) in addition to yeast, some mushrooms, bacteria, shellfish, krill, shrimp, salmon, lobster, and some plants [18].

The Food and Drug Administration (FDA) has predicated ASTX grade got H.pluvalis in Generally Recognized As Safe (GRAS) since 2010. It is suggested that consumption of up to 40 mg/d in humans doesn’t have adverse effects according to this list. Natural ASTX Complex, including extract of H.pluvalis, common fatty acids, and other carotenoid esters is recommended at a dose of 2–12 mg/day (mean dose 6 mg/d) by the FDA [34]. There are many products in the market as ASTX supplements (Table 1).

Table 1: ASTX products being in market.

Oxidative stress in senescence

Sections of DNA related to aging, progressive faults of protein synthesis, immune attacks in developed organisms against selfantigens, and free radical damage are assumed in the nature of the aging process [35]. Antagonistic pleiotropy theory, fallout accumulation theory, insulin resistance, advanced glycation, wrong destruction theory, autoimmunity, circadian rhythm, and evolutionary theory are some of the propounded theories. Of these theories, free radical theory is involved in both genetic mutations and aggregation of cellular catabolites [36]. Although the aging process and its mechanisms have not been clarified yet, of attractive aging theories, wear and tear, genetic programming telomere, pace of life, mitochondria, endocrine and wrong destraction theory, hypothesis of advanced DNA damage and free radical theory are updated [37].

Harman (1956) has suggested that accrescent free radicals in the wake of molecular oxygen catalyzed in cells cause senescence by their side effects on cells and tissues [5]. Free radicals, forming from exogenic and endogenic resources in cells, have detrimental effects on both the cell nucleus and genomes of mitochondrial DNA [38]. It is asserted that environmental factors, genetic modification, diseases, and naturally-occurring free radicals in aging trigger senescence [39].

There are produced reactive oxidative species in the course of diverse cell reactions. These species are undergone detoxification by enzymes and antioxidant compounds (Figure 3) [40].

Figure 3. Detoxification of reactive oxidative species by enzymes.

It is discussed that damage signaling pathways increase in company with aging situation, decreasing general physiological capacity and increasing mortality. One of these pathways is DNA damage response (DDR). Inadequency and defectiveness in DDR as well as accumulation of DNA lesion trigger aging and pathological diseases associated with aging. p53 tumor suppressor protein expressed in responsed to DNA damage modulates cascade I and therefore it is accepted as an important DD [41].

Activity of Nrf2 being another DDR play a repressive role in numerous steps of aging and diseases related with aging. Nrf2 also creates a response by increasing expression of detoxification genes [42].

The longevity-modulating genes found out past two years are preserved by from smallest living to human. Of these genes, Cell aging regulation system (CARS) includes diverse aging effectors modulating longevity, such as lipid unsaturation, mitROS production, mitochondrial DNA repair, autophagy, apoptosis, proteostasis or telomere shortening. Because of these properties, CARS is inclusory such as to previous theories [43].

Mitochondria is origo of intracellular free radical species. Mitochondrial DNA (mtDNA) is exposed to grave oxidative stress. An important oxydant, 8-hydroxydeoxyguanosine (8OHdG), provokes erroneous conjugation and point mutations. Due to the fact that disruptions in mtDNA based on these errors may ocur, it is assumed that mtDNA damage is a reason for aging [44]. Mitochondria theory is descriptive of senescence as increased production of free radicals due to disorders in the mitochondria electron transport chain and premediates that aging is significantly alleviation in enzymes, especially transporter enzymes, with age [45]. One study (2016), seeking out relationship between hippocampal proteins and age, found that proteins in electron transport chains and fusion pathways of synaptic vesicles consistently decrease with age [46]. Unpaired protein-2 (UCP-2), a mitochondrial transporter protein, may have an impact on life span in humans. In reference to this consideration, rats without UCP-2 matureity earlier and have a shorter lifetime [47]. A study (2011) that investigated impacts of senescence on activity of the mitochondria electron transport chain showed that the most reduction is seen in activity of complex-4 while complex-2 does not change [48]. Senescence is associated with oxidative stress and accumulation of mutant mtDNA. Hydrogen peroxide level, releasing of NADPH oxidase-2 (NOX-2), 8OHdG and accumulation of mutant mtDNA increase and caspase-3- dependent apoptosis pathway in a study of Du et al. working on old rats [49]. Dysfunction of Nrf2 in vessels further augments oxidative stress levels occurring with age [50,51], going into diverseness in response of fibroblasts human of old and young to oxidative stress, found that expression of phase-2 enzymes, such as CAT and SOD, is greater in younger individuals than in older [51]. They noted that lifespan of rats without SOD is substantially shorter and these rats age quickly [52].

Based on alterations in mitochondria, diseases with aging, such as Alzheimer’s disease (AD), Parkinson disease (PD), amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD), come in sight. Of these diseases, accumulations of Aβ protein in AD affect Complex-IV and activity of α-ketoglutarate dehydrogenase. This protein also binds to Aβ-binding alcohol dehydrogenase. Of another disease, Lewy bodies accumulate in mitochondria and decrease Complex-I activity in PD. In another disease, ALS, it is a matter of abnormal outturn of mitochondrial ROS depending on SOD 1 mutations. In HD, there is a decrease in Complex-II. All of these mitochondrial disfunctions by diseases are shown in Figure 4 [53].

Figure 4. The role of mitochondria in age-related neurodegenerative diseases. (A) In AD (B) In PD (C) In ALS (D) In HD [53].

Effects of Astaxhantin on oxidative stress

β-carotene and vitamin C, being antioxidant, are located in both inside and outside of cell lipid layer of membrane. However, besides participation in the double-layer membrane, the presence of the cell both inside and outside gives ASTX better protection than others (Figure 5) [54].

Figure 5. Protection of ASTX against ROS in the double-layer membrane [54].

It is adduced in studies related to astaxhantin that ASTX decreases oxidant stress by inducing antioxidant enzymes, such as Nrf2, PI3K/Akt, SOD and glutathione, and their pathways [55-58].

It is separately researched as mice, human and cell studies.

Results and Discussion

Mice studies

Effects ASTX on antioxidant enzymes: Al-Amin et al. were studied on mice to measure the levels of anti-oxidative enzymes in the prefrontal cortex (PFC), striatum (ST), hippocampus (HP), and liver (LV) in groups [59]. Treatment of 2 mg/kg ASTX for 28 days induced CAT (in ST and LV) and SOD (ST, HP and LV) while supressed nitric oxide (in PCF, ST, HP and LV), glutathione (in LV) [59]. To investigate effects of ASTX on antioxidant enzymes, 10 mg/kg ASTX were given for 28 days and 100 mg/kg ASTX were given for 7 days to rats and, as a result, SOD activity increased for both dose levels [60,61]. Al- Amin et al. gave 2 mg/kg/day ASTX to old rats and found that activities of CAT and SOD and glutathione levels increased at the end of the study [62].

In a study on adult Wistar male rats for 45 days that Mattei et al. carried on effect of ASTX on oxidative stress due to fish-oil, while only fish-oil (10 mg EPA/kg body weight and 7 mg DHA/kg body weight) decreased activities of SOD, CAT and glutathione reductase, ASTX administration (1 mg/kg body weight) after fish-oil improved these activities [63]. Otsuka et al. investigated effect of ASTX on photoreceptor degeneration induced by fluorescent and noted 8-OHdG level increased in outer core layer. After ASTX administration (100 mg/kg, at 6 h before and at 0, 6, 12, 24, 36, 48, and 72 h after light irradiation) to male albino ddY mice, there was no effect of ASTX on mRNA synthesis of Sod1, metallotionein-II and II [64]. ASTX administration of 100, 250 and 500 mg/kg body weight to ulcerated albino Wistar rats promoted SOD and CAT levels [65].

Al-Amin et al. administrated ASTX (20 mg/kg body weight/day) to Swiss albino male mice for 42 days. Glutathione concentrations of frontal cortex, striatum and cerebellum decreased after administration. In addition to this, malondialdehyde levels diminished in striatum, hypothalamus and hippocampus [66]. Superoxide anion levels in neutrophile of alloxane induced diabetic Wistar male rats fed ASTX (20 mg ASTA/kg of body weight/day, for 30 days) did not change, while there was a diminishment in TBARs levels. At the same time, this administration increased GPx level further [67].

Effects ASTX on reactive oxygen species: Pan et al., who studied adult rats, reported that ASTX given in doses of 5 and 10 mg/kg for a week suppresses reactive oxygen species and activates the defense system of antioxidants [68]. In another study (2016), oxidative stress levels were evaluated, and old rats were given 1.7 mg/day ASTX. They found that the level of plasma oxidative stress was lower while antioxidant levels were higher by the end of 72 weeks [69]. After administration of 25 and 50 mg/kg ASTX in rats, there were decreases in levels of 8OHdG and malondialdehyde [70].

Metabolic disorders such as oxidative stress, happens after high fatty diets and this diet causes neural damage and alterations in neurogenesis and memory. In a study researched effects of antioxidants (ASTX, vitamin C and E; 0,6 g/kg, 0,2 g/kg and 0,2 g/kg, respectively, for 180 days) on potential side-effect of high fatty diet, ASTX administration to male Wistar rats enhanced total antioxidant capacity [71]. In another study sought relevany between ASTX and 8-OHdG level, both 300 and 600 mg/kg/day administration for 3 weeks of ASTX to male SHRSP rats decreased urinary 8-OHdG level [72].

Yeh et al. gave 0.6 mg/kg and 3 mg/kg ASTX to old rats for 8 weeks. They noted that levels of 8OHdG, nitrotyrosine, acrolein and transcription of nuclear factor kappa B (NF-kB) decreased in both groups [73].

Effects ASTX on pathways of oxidative stress: Masoudi et al. asserted that the release of caspase-3 significantly decreased when adult rats were given 10 μL/0.2 mM ASTX [74]. In a rat study, administration of 20 μM/0.1 mM ASTX activated the Nrf2 – ARE pathway [75]. Masoudi et al. to examined the therapeutic potential of AST on adult rats after severe spinal cord injury. 10 μL/0,2 mM ASTX, ASTX reduced expression of Bax and Cleaved-caspase-3 proteins and increased expression of the Bcl-2 protein [74].

Fakhri et al. and Rahman et al. also found that ASTX lessened expression of TNF-α [76,77]. Amyloid plaques appear in pathogenesis of AD and have cytotoxic property. In a study, relation between ASTX and Bexratone was viewed by Fanaee- Danesh et al. [78]. Both two administrations had similar effect. By way of ASTX, Female 3xTg AD mice fed ASTX (80 mg/kg, for 6 days) had reduced Aβ oligomers [78]. All the mice studies mentioned in review are demonstrated in Table 2.

Table 2: Mice studies related with ASTX, their procedures and results.

Cell studies

Effects ASTX on oxidative stress: Yamagishi and Aihara administrated different doses of ASTX (1 nM, 10 nM and 100 nM) to rat retinal ganglion cells and found that the lifespan of cells increased, and the administration of 100 nM ASTX markedly prevented DNA damage and apoptosis [79]. In other study, it was aimed at determination of the effect of ASTX on the interplay of NRF2 and NFκB for its antiinflammatory and antioxidant properties in macrophages. In this study, treatment of macrophages cells with 25 μM ASTX for 24 hours reduced mRNA levels of IL-6, IL-1β and TNF-α [80]. In a culture study, a dose of 1.25-5 μM ASTX increased secretion of HO-1 and Nrf2 and decreased the release of caspase-3, -8 and -9 and lactate dehydrogenase. Antioxidant response components (ARE) also increased in this culture study [81].

Effects ASTX on reactive oxygen species: Another cell culture study that distinct ASTX doses (5 μM, 10 μM and 20 μM) for one hour found that production of intracellular reactive oxygen and cell death due to hydrogen peroxide were diminished [82]. Guerra et al. sought connection between glycolaldehyde and human neutrophils. Combine application of vitamin C (100 mM) and ASTX (2 mM) decreased output of NO and H2O2 in cells, unfavourable impacts of glycolaldehyde [83]. Whereas, mitochondrion contributes to energy production by redox, it also causes ROS to occur. Resultant ROS and ASTX were inspected by Wolf et al. [84]. PC12 cells incubated with 200 and 400 nM ASTX for 24 h were protected against cell death due to oxidative stress. However, 800 nM ASTX had a constructive effect on Jurkat cells. HeLa cell cultured with same dose for 6 h also provided a decrease in H2O2 levels [84]. In company with ASTX (25, 50, 100, 500 and 1000 nM, for 4 h and 24 h) cultured in human dopaminergic neuroblastoma SH-SY5Y cells, it was provided a decrease in DHA-OOH levels. ROS production was protected by ASTX in these cells [85]. CDX-085 is a pro-drug, more soluable in water than pure ASTX form. Proinflammatory ONOO- formation was reduced in platelets from C57BL/6 rats fed 0,4% CDX-085 for 2 weeks that were treated with 1 μM ASTX [86].

Fatty acids subject to concentration and type alter leucocyte function. Campoio et al. searched effects of ASTX on excess of oxidative stress based on fatty acids in human peripheral blood lymphocytes. In contrast to adverse effects of fatty acids, ASTX implementation (2 μM of ASTA for 24 h) reduced cellular NO and H2O2 production. Beside this, increasing activities in SOD, CAT and GPx by fat was lowered by ASTX [87].

Effects ASTX on enzymes: In a study on cell culture done by Franceschelli et al., horary incubation of 10 μM ASTX also induced antioxidant enzyme activation (CAT and SOD) [88]. ASTX being one of the major xanthophylls indicates an inhibitor impress on CYP isoenzymes. Astaxanthin (from 0,05; 0,5 to 5 μM) implemented on human liver microsome had an weak effect on CYP2C19 and IC50 value was 16,2 μM [52,89].

All the cell studies mentioned in review are demonstrated in Table 3.

Table 3: Cell studies related with ASTX, their procedures and results.

Conclusion

Reactive oxygen species emergent through senescence further expedite the aging process. Several studies that investigated effects of ASTX on oxidative stress suggested that ASTX inhibits oxygen species by impacting enzymes and their pathways. In addition to this, ASTX enhances activation of the antioxidant defence system, which decreases with age. Most of studies on rats and limited availability of human studies cause to be restricted proposal usage of ASTX as diet supplement. Besides this situation, indicated classification diary amounts of ASTX by age may put some teeth into safe intake of ASTX.

Effect and important keystone is also confidential doses of ASTX for both rats and human. It should be paid regard to determine these doses for especially human from the viewpoint of gender, age, health or existence of other diseases, used drugs, genotype and their biochemical values.

Senescence is an inexpugnable sooth. Despite this, reasons leading to it may be intercepted and aging may be postponed by antioxidants, nutritional behaviors and studies. Some cell types used in searches, such as microsome, may not represent real physiology. Of other cruces, procedurs of ASTX and researches pertain to perfect physiology should be done more.

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