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Further pharmacological evidence of the neuroprotective effect of catalpol from Rehmannia glutinosa.

Abstract

We have previously evaluated the neuroprotective effect of catalpol on aging mice induced by D-galactose, in which catalpol treatment ameliorated cognition deficits and attenuated oxidative damage in mice brain. To thoroughly elucidate the anti-aging effects of catalpol, the liver and spleen antioxidative systems and energy metabolism in senescent mice induced by D-galactose have been studied. Except control group, mice were subcutaneously injected with D-galactose (150 mg [kg.sup.-1] body weight) for 6 weeks. Meanwhile, drug group mice were treated with catalpol (2.5, 5, 10mg [kg.sup.-1] body weight) and piracetam (300mg [kg.sup.-1] body weight) for the last 2 weeks. The activities of endogenous antioxidants and the level of glutathione (GSH) and lipid peroxide in the liver and spleen were assayed. Compared to control group, model group mice had significantly lower spleen index (spleen weight/body weight), lower level of GSH, lower activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), higher level of malondialdehyde (MDA) in the liver and spleen. However, catalpol administration markedly reversed these effects of senescence induced by D-galactose. Simultaneously, catalpol noticeably elevated the decreased activities of lactate dehydrogenase (LDH), glutamine synthetase (GS), [Na.sup.+] [-K.sup.+] -ATPase, [Ca.sup.2+] [-Mg.sup.2+]-ATPase and decreased the elevated activity of creatine kinase (CK) in mice liver or spleen. These results implied that the anti-aging effects of catalpol were achieved at least partly by promoting endogenous antioxidant enzyme activities and normalizing energy disturbance. Catalpol may be a potential anti-aging agent and worth testing for further preclinical study aimed for senescence or neurodegenerative diseases such as Alzheimer's and Parkinson's diseases.

(C) 2008 Elsevier GmbH. All rights reserved.

Keywords: Rehmannia; Catalpol; Antioxidant and antiaging effect; Neuroprotection

Introduction

Rehmannia, known as dihuang and disui in Shennong Bencao Jing (ca. 100 A.D.), refers to the root of Rehmannia glutinosa, an herb of the Scrophulariaceae family. Rehmannia is far more frequently prescribed in China than in other countries and has been used to replenish vitality, strengthen the liver, kidney, heart and for treatment of a variety of ailments like diabetes, anemia, and urinary tract problems, especially to be used in cases of kidney yin deficiency that is associated with aging. Kidney yin deficiency is regarded as the origin of age-related memory loss in Chinese traditional medicine. Therefore, Rehmannia is now more often used to treat age-related disorders, such as aging and dementia. Rehmanniae Decoction of Six Ingredients has long been used in age-related diseases and its therapeutic efficacy has been confirmed by many studies. Chronic administration of Rehmanniae Decoction of Six Ingredients to senescence-accelerated mouse promoted the spatial memory ability in water maze test and partially improved the learning behavior in conditioned avoidance performance (Zhou et al., 1999; Cui et al., 2004).

In our search for active ingredients, catalpol (Fig. 1), an iridoid glycoside, was isolated from fresh root of Rehmannia with column chromatography method. Catalpol possesses many therapeutic effects such as anti-inflammatory, promotion of sex hormones production, reduction of bleeding, protection of liver damage, and reduction of elevated blood sugar. Our previous works have demonstrated that catalpol can protect against [H.sub.2] [O.sub.2]-induced oxidative damage on PC12 cells and LPS-induced neurotoxicity on dopaminergic neurons (Jiang et al., 2004; Tian et al., 2006). In animal models, we found that catalpol could enhance cognitive performance in transient global ischemia in gerbils and protect mice brain from oxidative damage and mitochondrial dysfunction induced by rotenone (Li et al., 2004; Mao et al., 2007). Most important is that catalpol could increase presynaptic proteins and up-regulate relative signaling molecules in the hippocampus of the aged rats (Liu et al., 2006). Considering these neuroprotective effects of catalpol and the anti-aging effect of Rehmannia, we speculate that catalpol may be the main anti-aging active component of this Chinese crude drug. So we use aged animal model to verify the anti-aging effect of catalpol and the mechanisms underlying its effect.

[FIGURE 1 OMITTED]

These days, the "free radical theory of aging" is showing promise in helping to understand the process of aging and in finding effective anti-aging agents. The theory postulates that the generation of reactive oxygen species (ROS) or free radicals can lead to cell and tissue damage paralleled by alterations in the function of the genetic apparatus, resulting in aging and untimely cell death (Harman, 1956). To protect cells against oxidative damage produced by oxidants during the oxygen metabolism, an antioxidant system has presumably evolved in aerobic organisms. Enzymatic antioxidants, like superoxide dismutase (SOD) or glutathione peroxidase (GSH-PX), as well as non-enzymatic antioxidants like glutathione (GSH), can scavenge free radicals or prevent their formation. Lipid peroxidation plays an important role in tissue injury. Malondialde- hyde (MDA), a stable metabolite of the free radical-mediated lipid peroxidation cascade, is widely used as marker for oxidative stress.

Furthermore, aging also results in energy metabolism failure with decrease in adenosine triphosphate (ATP) formation (Tian et al., 2005) and activity of lactate dehydrogenase (LDH) and excessive accumulation of lactic acid (Yue et al., 1999). Previous studies have demonstrated that oxidative processes often result in changes of the activities of key enzymes, including glutamine synthetase (GS), creatine kinase (CK) and tyrosine hydroxylase (Hensley et al., 1995). These changes result in a proceeding loss of cellular function which is regarded as a main reason for aging (De Grey, 1997).

Rodent chronically injected with D-galactose has been used as an animal aging model for anti-aging pharmacology research (Wei et al., 2005). Recently, we found that catalpol could enhance cognitive performance in aged mice induced by D-galactose and reduce oxidative stress by increasing the activities of SOD and GSH-Px and decreasing the concentration of MDA in mice brain (Zhang et al., 2007). These indicated that catalpol may be of potential use in the therapy of anti-aging. The aim of this study was to investigate the potential role of catalpol in reducing oxidative stress in the liver and spleen of senescent mice induced by D-galactose by quantifying lipid peroxidation and various antioxidant enzyme activities. In addition, we intended to explore the effect of catalpol on mice liver or spleen energy metabolism via detecting the activities of LDH, CK, GS, [Na.sup.+] [-K.sup.+] -ATPase, [Ca.sup.2+] [-Mg.sup.2+]-ATPase

Matetials and methods

Reagents and drugs

D-galactose was purchased from Shanghai Yuanju Chemical-Regent Company (Shanghai, China) and dissolved in 0.9% saline at concentrations of 3%. Catalpol (separation process see Preparation of catalpol) and piracetam (Pingyuan pharmaceutical factory, Shandong, China) were dissolved in physiological saline. Commercial kits used for determination of MDA, SOD, GSH, GSH-Px, LDH, CK, GS, [Na.sup.+] [-K.sup.+] -ATPase and [Ca.sup.2+] [-Mg.sup.2+]-ATPase were purchased from Jiancheng Institute of Biotechnology (Nanjing, China).

Preparation of catalpol

Fresh root of Rehmannia (1 kg) were homogenated and extracted three times at room temperature with 95% EtOH (each 51) for 24 h. The extracts were filtered and evaporated under reduced pressure (50 [degrees]C, 0.08 MPa) to give a residue, which afforded a solution by dissolving in 11 deionized [H.sub.2]O. After centrifugation, the obtained solution was passed through a D101 macroporous resin column (the volume is 31) eluted with 91 [H.sub.2]O, 91 5% EtOH and 91.5% EtOH. The 5% EtOH elution on removal of the solvent under reduced pressure (50 [degrees]C, 0.08 MPa) provided 2.62g brown powder, which was subjected to an open column chromatography on silica gel (100-140 mesh) eluted with a [CHCl.sub.3]-MeOH gradient. The thin-layer chromatography (TLC) technique was used to detect the eluted materials from the column. Fraction (0.46 g) eluted with [CHCl.sub.3]-MeOH (8:2) was identified as catalpol compared to its standard substance. In order to obtain pure catalpol, this fraction was subjected to another silica gel (200-300 mesh) column with same eluting solvent. The purity of the compound (0.28 g) was more than 90% purity by high-performance liquid chromatography (HPLC) analysis. The chemical and physical data of the isolated catalpol agree with those of the literature (Oshio and Inouye, 1982).

Animals and drug administration

Kunming mice aged 3 months (25-30 g) from Experimental Animal Center of Dalian Medical University (China) were housed five per cage in a temperature-controlled room (25[+ or -]2[degrees]C) on a standard 12/12h light/dark cycle (lights on at 07:00). They were allowed free access to food and water. The mice were randomly divided into three groups: control group (n = 10), model group (n = 10), catalpol group (n = 30) and piracetam group (n = 10). The mice of model group and drug group were subcutaneously injected with D-galactose at the dose of 150 mg [kg.sup.-1] body weight once daily for 6 weeks while those of control group were treated with same volume physiological saline. From the fifth week, catalpol and piracetam group mice were subcutaneously injected with catalpol at the dose of 2.5, 5, 10mg [kg.sup.-1] and piracetam at the dose of 300 mg [kg.sup.-1] per day respectively after injection of D-galactose. Control group and model group mice were administered with same volume physiological saline. All experimental procedures were conducted in conformity with institutional guidelines for the care and use of laboratory animals in Dalian Medical University (Dalian, China) and conformed to the National Institutes of Health Guide for Care and Use of Laboratory Animals (Publication No. 85-23, revised 1985). Each experimental protocol was statistically designed to use the minimal number of animals.

Preparation of tissues and homogenates

After drug administration, weights of all mice were recorded and then sacrificed by decapitation. Livers and spleens were removed quickly on a cold plate, weighed and homogenized respectively with ice-cold saline and stored at -70 [degrees]C for biochemical analysis. Before detection, the homogenate (10%) was centrifuged at 4000g at 4[degrees]C for 10 min, and the supernatant was used for assay.

Preparation of liver mitochondria

Livers were washed three times with fresh MSME medium (220 mM mannitol, 70 mM sucrose, 5mM Mops, 1 mM EGTA, pH 7.4). Two milliliter of MSME containing 3 mg of defatted BSA was added and the mixture was homogenized in a glass homogenizer, centrifuged at 600g for 5 min. The supernatant was filtered through four layers of gauze and spun at 12000g for 5 min to obtain a mitochondrial pellet, which was washed in 2 ml of MSME and centrifuged at 8000g for 5 min. The final pellet was resuspended in MSME.

Biochemical assays

The assays for GSH, SOD, GSH-PX, LDH, GS, CK and MDA in the liver and spleen, as well as [Na.sup.+]-[K.sup.+]-ATPase and [Ca.sup.2+]-M[g.sup.2+]-ATPase in liver mitochondria were all determined by using commercially available kits. All procedures completely complied with the manufacture's instructions.

Protein assay

Protein concentration was measured by the method of Bradford (Bradford, 1976). Bovine serum albumin was used as standard.

Statistical analysis

Data were expressed as mean[+ or -]S.D. and evaluated using one-way ANOVA followed by Student's t-test. A criterion of <0.05 was accepted as statistically significant.

Results

Effects of catalpol on spleen index of senescent mice induced by D-galactose

The changes in the spleen index of mice are depicted in Fig. 2. Model group mice had a significantly lower spleen index (5.9[+ or -]0.4g [kg.sup.-1] body weight) than those of control group (9.6[+ or -]1.4g [kg.sup.-1] body weight). When treated with catalpol at 2.5, 5 and 10mg [kg.sup.-1] doses for 2 weeks, catalpol group mice showed significant increase in spleen index (7.2[+ or -]1.1, 7.7[+ or -]1.4 and 10.1[+ or -]2.0g [kg.sup.-1] body weight respectively, at least <0.05 vs. model group). Spleen index of piracetam group also increased to 9.9[+ or -]1.8 (<0.01 vs. model group).

[FIGURE 2 OMITTED]

Effects of catalpol on SOD, GSH-PX activities and GSH, MDA level in the liver and spleen of senescent mice induced by D-galactose

The activities of SOD, GSH-PX and the level of GSH in the liver significantly declined in model group mice as compared with control group mice (Table 1, <0.01). A significant enhancement of SOD (<0.01), GSH-PX (<0.05) activities and GSH (<0.01) level was observed in response to catalpol at doses of 2.5, 5 10 mg [kg.sup.-1] for 2 weeks as compared to model group. The MDA level in livers of model group were significantly higher than those of control group (Table 1, <0.01) and this increase was attenuated by treatment with catalpol at doses of 2.5, 5 or 10 mg [kg.sup.-1] (<0.01 vs. model group). Positive drug group showed same effect as catalpol <0.05 vs. model group).

The activities of SOD, GSH-PX and GSH level in the spleen are shown in Table 2. The activities of SOD, GSH-PX and GSH level of model group mice were significantly lower as compared with control group (<0.01), which were subsequently normalized by prolonged catalpol administration (2 weeks). All doses of catalpol reached significant levels (at least <0.05) versus model group. Lipid peroxidation was significantly high in mice spleen of model group mice (Table 2, <0.01 vs. control group) and a decrease in MDA level was shown in catalpol administration group (<0.01 vs. model group). Same tendency appeared in positive drug group.
Table 1. Effects of catalpol on superoxide dismutase (SOD),glutathione
peroxidase (GSH-PX), glutathione (GSH) and malondialdehyde (MDA) in
the liver of senescent mice induced by D-galactose

 Groups SOD (U/ GSX-PX (U/ GSH (mg MDA (nmol/
 mg protein) mg protein) GSH/g mg protein)
 protein)

Control 84.73 [+ or -] 2.10 [+ or -] 54.31 [+ or -] 5.41 [+ or -]
group 9.12 0.23 4.60 0.92

Model 40.99 [+ or -] 1.10 [+ or -] 26.98 [+ or -] 8.87 [+ or -]
group 7.24 ## 0.25 ## 4.47 ## 0.93 ##

Catalpol 66.06 [+ or -] 1.51 [+ or -] 41.20 [+ or -] 6.06 [+ or -]
low(2.5 8.33 # ** 0.28 ## * 4.67 ## ** 0.55 **
mg/kg)

Catalpol 73.75 [+ or -] 1.57 [+ or -] 40.85 [+ or -] 5.84 [+ or -]
middle 7.72 # ** 0.30 ## * 4.19 ## * 0.25 **
(5 mg/kg)

Catalpol 80.74 [+ or -] 1.58 [+ or -] 45.96 [+ or -] 4.61 [+ or -]
high 10.30 ** 0.26 ## * 6.48 # ** 0.72 **
(10mg/kg)

Piracetam 63.66 [+ or -] 1.53 [+ or -] 38.14 [+ or -] 7.04 [+ or -]
(300mg/kg) 6.12 ## ** 0.162 ## * 7.44 ## * 0.73 # *

Values are expressed as mean [+ or -]SD. ##<0.01, ## < 0.05
as compared to normal control; ** < 0.01, * < 0.05 as compared to
model group, n = 10.

Table 2. Effects of catalpol on superoxide dismutase (SOD),
glutathione peroxidase (GSH-PX), glutathione and malondialdehyde
(MDA) in the spleen of senescent mice induced by D-galactose

Groups SOD (U/ GSX-PX (U/ GSH (mg GSH MDA (nmol/
 mg protein) mg protein) /g protein) mg protein)

Control 9.53 [+ or -] 1.93 [+ or -] 33.75 [+ or -] 1.23 [+ or -]
group 1.16 0.33 4.48 0.08

Model 3.98 [+ or -] 0.92 [+ or -] 20.02 [+ or -] 1.85 [+ or -]
group 0.68 ## 0.22 ## 4.92 ## 0.16 ##

Catalpol 7.29 [+ or -] 1.34 [+ or -] 28.11 [+ or -] 1.49 [+ or -]
low (2.5 1.46 # ** 0.23 ## * 5.27 * 0.16 # **
mg/kg)

Catalpol 7.43 [+ or -] 1.54 [+ or -] 29.50 [+ or -] 1.51 [+ or -]
middle 1.48 ** 0.33 # ** 1.92 * 0.15 ## *
(5 mg/kg)

Catalpol 8.75 [+ or -] 1.73 [+ or -] 28.67 [+ or -] 1.36 [+ or -]
high 1.31 ** 0.38 ** 4.27 * 0.17 **
(10mg/kg)

Piracetam 8.12 [+ or -] 1.69 [+ or -] 25.72 [+ or -] 1.57 [+ or -]
(300mg/kg) 1.09 ** 0.53 * 5.79 * 0.21 # *

Values are expressed as mean[+ or -]SD. ##< 0.01, # <0.05 as
compared to normal control; ** <0.01, * <0.05 as compared to
model group. n = 10.


Effects of catalpol on LDH, GS and CK activities in the liver and spleen of senescent mice induced by D-galactose

The activities of LDH and GS in the liver significantly declined in model group mice as compared with control group mice (Table 3, LDH, P< 0.1; GS, p > 0.05). A significant enhancement of LDH (p <0.01) and GS (at least p < 0.05) activities was observed in response to catalpol doses of 5, 10 mg [kg.sup.-1]- and piracetam at dose of 300mgkg_for 2 weeks as compared to model group. There was no statistic effect in low dose group. The activity of CK in the liver of model group was significantly higher than that of control group (Table 3, p < 0.0l) and this increase was attenuated by treatment with catalpol at doses of 5 or l0mgk[g.sup.-] (p < 0.05 vs. model group). But low dose of catalpol and piracetam did not reach significant level.

The activities of LDH and GS in the spleen are shown in Table 4. The activities of LDH and GS of model group mice were significantly lower as compared with control group (p < 0.01), which were subsequently normalized by prolonged catalpol administration (2 weeks). All doses of catalpol and piracetam reached significant levels (at least p < 0.05 vs. model group) in LDH while only low and middle doses of catalpol reached significant level in GS (p < 0.01 vs. model group). The activity of CK was significantly high in mice spleen of model group mice (Table 4, p < 0.05 vs. control group) and catalpol and piracetam administration showed a decrease in CK activity (at least p < 0.05 vs. model group).

Effects of catalpol on the activities of N[a.sup.+] [-K.sup. +] - ATPase and C[a.sup.2 +] -M[g.sup.2 +] -ATPase in liver mitochondria of senescent mice induced by D-galactose

Fig. 3 shows the changes of N[a.sup. +] [-K.sup. +] -ATPase and C[a.sup.2 +] -M[g.sup.2 +] -ATPase activities in liver mitochondria of senescent mice induced by D-galactose. It can be seen that model group mice had a significant decrease in N[a.sup. +] [-K.sup. +] -ATPase and C[s.sup.2 +] -M[g.sup.2 +] -ATPase activities which were reduced by 49.8% and 33.3%, respectively, compared to control group. Catalpol treatment significantly protected the liver against ATPase disturbances and the activities of N[a.sup. +] -ATPase and C[a.sup.2 +] -M[g.sup.2 +] -ATPase found in catalpol group were higher than those in model group, corresponding to 65.6%, 80.1% of the control in low dose group, 67.7%, 79.7% of the control in middle dose group and 68.0%, 84.6% of the control in high dose group, respectively. Piracetam also elevated N[a.sup. ] [-K.sup. +] -KAPase and C[a.sup.2 +] -M[g.sup.2 +] -ATPase activities to 82.2% and 83.9% of the control, respectively. All drugs reached significant level compared to the control group (at least p < 0.05).

[FIGURE 3 OMITTED]
Table 3. Effects of catalpol on lactate dehydrogenase (LDH),
glutaminesynthetase (GS) and creatine kinase (CK) in the liver of
senescent mice induced by D-galactose

Groups LDH (U/mg GS (U/mg CK (U/mg
 protein) protein) protein)

Control group 476.97 [+ or -] 7.17 [+ or -] 0.16 [+ or -]
 79.08 1.59 0.03

Model group 266.61 [+ or -] 4.19 [+ or -] 0.26 [+ or -]
 52.52 ## 0.59 ## 0.04 ##

Catalpol Low 333.49 [+ or -] 4.35 [+ or -] 0.19 [+ or -]
(2.5mg/kg) 61.87 ## 1.21 ## 0.04

Catalpol middle 406.88 [+ or -] 6.97 [+ or -] 0.21 [+ or -]
(5mg/kg) 56.64 ** 1.29 ** 0.04 *

Catalpol high 415.75 [+ or -] 6.37 [+ or -] 0.22 [+ or -]
(10mg/kg) 76.50 ** 0.84 * 0.03 *

Piracetam ) 469.45 [+ or -] 9.02 [+ or -] 0.24 [+ or -]
(300mg/kg 74.59 ** 1.00 ** 0.03 ##

Values are expressed as mean [+ or -] SD.
## < 0.001, # p < 0.05 as compared to normal control;
** < 0.01, * <0.05 as compared to model group. n = 10.

Table 4. Effects of catalpol on lactate debydrogenase (LDH),
glutamine synthetase (GS) and creatine kinase (CK) in the spleen of
seneseent miee induced by d-galactose

Groups LDH (U/mg GS (U/mg CK (U/mg
 protein) protein) protein)

Control group 613.70 [+ or -] 11.62 [+ or -] 0.95 [+ or -]
 46.03 1.43 0.21

Model group 424.09 [+ or -] 5.22 [+ or -] 1.17 [+ or -]
 58.50 ## 0.96 ## 0.12 #

Catalpol Low 565.18 [+ or -] 7.87 [+ or -] 0.94 [+ or -]
(2.5mg/kg) 89.54 ** 0.73 ## ** 0.21 *

Catalpol middle 524.76 [+ or -] 10.31 [+ or -] 0.92 [+ or -]
(5mg/kg) 55.53 # * 1.68 ** 0.15 *

Catalpol high 580.94 [+ or -] 7.25 [+ or -] 0.95 [+ or -]
(10mg/kg) 51.69 ** 1.90 ## 0.16 *

Piracetam 511.60 [+ or -] 6.74 [+ or -] 0.71 [+ or -]
(300mg/kg) 77.66 ## 0.77 ## 0.20 **

Values are expressed as mean [+ or -] SD.

## p < 0.01, # < 0.05 as compared to normal control;
** < 0.01, * < 0.05 as compared to model group. n = 10.


Discussion

During aging, a general decline in various biochemical and physiologic functions is noted in most organs, resulting in increased susceptibility to age-associated diseases (Matsugo et al., 2000). According to the theory of Chinese traditional medicine, liver and spleen are very important to aging. Majority of scholars studying Chinese traditional medicine recognize that internal organ weakness causes human aging. Therefore, we detected a series of enzyme activities of mice liver and spleen. Our data demonstrated that the mean spleen index of model group mice was significantly lower than that of normal control group mice, possibly representing the function degradation of aged spleen. The mice injected with catalpol for 2 weeks gained more spleen index than model group mice, indicating that they had a higher metabolic rate than senescent mice.

Oxidative stress and reactive oxygen species (ROS) are proposed to be major contributors to the aging process and many neurodegenerative diseases such as Alzheimer's and Parkinson's diseases (Ames et al., 1993). It has been reported that free radicals were increased in D-galactose treated animals (Cui et al., 2006; Song et al., 1999). In the present study, subcutaneous administration of D-galactose for 6 weeks caused impairments of antioxidant enzyme activities of SOD, GSH-PX in mice liver and spleen. Catalpol could balance the endogenous antioxidant in these organs by increasing the level of GSH and activities of SOD and GSH-PX. These results were completely consistent with previous study (Li et al., 2007; Kedziora-Kornatowska et al., 2007; Mauriz et al., 2007), suggesting that an age-dependent decline of antioxidant enzyme activities occurred in aged mice. Catalpol seemed to partly attenuate this aging effect. MDA is a by-product of lipid peroxidation induced by free radicals, and is widely used as a biomarker of oxidative stress. Catalpol treatment significantly reduced the increased MDA level induced by D-galactose.

Regarding the biochemical assays, energy metabolism failure occurred in the liver and spleen of senescent mice induced by D-galactose. As a result, LDH, N[a.sup. +] [-K.sup.-] -ATPase and C[a.sup.2 +] -M[g.sup.2 +] -ATPase activities decreased. Treatment of catalpol reversed all these changes, indicating its protective effects on improving energy metabolism. In our experiment, model group mice showed a higher CK activity in the liver and spleen compared to model group mice, and catalpol administration decreased the activity of this enzyme. Because CK is sensitive to oxidative modification, it is possible that the changes observed in this study result from free radical damage. So the increase of CK activity in model mice liver and spleen may be a compensative response of organs. Glutamine synthetase (GS) is a key enzyme for Gln homeostasis. Glutamine synthetase undergoes oxidative inactivation and is very sensitive to oxidative stress (Butterfield et al., 1997). Our results showed that catalpol could inhibit the decrease of GS activity in senescent mice liver and spleen induced by D-galactose, which were consistent with previous study (Aksenova et al., 1998).

In summary, catalpol could elevate spleen index, increase the level of GSH and activities of SOD and GSH-PX, as well as decrease the level of MDA in the spleen and liver of aged mice. Simultaneously, catalpol could enhance the activities of LDH and GS and depress the activities of CK in the spleen and liver of senescent mice induced by D-galactose. Moreover, catalpol could also elevate N[a.sup.+] [-K.sup.1] -ATPase and C[a.sup.2 +] -M[g.sup.2 +] ATPase activities in liver mitochondria of aged mice. Our previous works had proved that catalpol had significant neuroprotective effect in vivo and in vitro damage models. This study is further evidence for the neuroprotection effect of catalpol. Taken together, catalpol could be implemented to minimize age-associated disorders where free radicals and energy metabolism failure were the major cause in some organs.

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Xiuli Zhang, Aihong Zhang, Bo Jiang *, Yongming Bao, Jingyun Wang, Lijia An

School of Environmental and Biological Science & Technology, Dalian University of Technology, Dalian 116024, China

* Corresponding author. Tel.: +86 411 84706355; fax: +86 411 84706365.

E-mail address: bojiang0411@yahoo.com.cn (B. Jiang).

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Author:Zhang, Xiuli; Zhang, Aihong; Jiang, Bo; Bao, Yongming; Wang, Jingyun; An, Lijia
Publication:Phytomedicine: International Journal of Phytotherapy & Phytopharmacology
Geographic Code:9CHIN
Date:Jun 1, 2008
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