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ORIGINAL ARTICLE
Year : 2014  |  Volume : 4  |  Issue : 1  |  Page : 64-68

A new weapon for memory power: Elephantopus scaber (Linn.)


1 Department of Pharmacology and Experimental Biology, Vedica College of Pharmacy, Ram Krishna Dharmarth Foundation University, Bhopal, India
2 Department of Pharmacology, Veer Surendra Sai Medical College, Burla, Odisha, India
3 Department of Pharmaceutical Science, Asia Metropolitan University, Cheras, Selangor, Malaysia
4 Department of Pharmacognosy and Phytochemistry, Vedica College of Pharmacy, Ram Krishna Dharmarth Foundation University, Bhopal, Madhya Pradesh, India

Date of Submission30-Aug-2013
Date of Acceptance04-Nov-2013
Date of Web Publication8-Jan-2014

Correspondence Address:
Amrita Bhaiji
Department of Pharmacognosy and Phytochemistry, Vedica College of Pharmacy, Ram Krishna Dharmarth Foundation University, Bhopal - 462 033, Madhya Pradesh
India
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Source of Support: Vedica College of Pharmacy, RKDF University, Bhopal, Madhyapradesh, India., Conflict of Interest: None


DOI: 10.4103/2231-0738.124616

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   Abstract 

Aims: To investigate the memory enhancing potential of ethanolic extract of Elephantopus scaber (Linn.) leaves (EESL) in Swiss albino aged mice along with its possible mode of action. Materials and Methods: The memory enhancing activity was estimated by measurement of transfer latency (TL) in elevated plus maze test; step-down latency (SDL) in passive avoidance test, cholinesterase and caspase level from brain homogenate of mice. The EESL at the dose of 150, 300, and 600 mg/kg of body weight was administered orally for 15 days to different groups (n = 6) of aged mice and was found dose dependent improvement in memory score after termination period. Results: In aged mice, EESL reversed significantly amnesiatic potential in TL and SDL, reduced significantly cholinesterase level, and increased significantly caspase level as compared to control group. Conclusions: These above finding suggest that the EESL may exhibit memory enhancing activity in aged mice and this enhancement of memory may be due to increase anticholinesterase and caspase activity in mice brain.

Keywords: Elephantopus scaber , estimation of cholinesterase and caspase level, step down latency, transfer latency


How to cite this article:
Sahoo HB, Mandal PK, Bhattamisra SK, Bhaiji A, Sagar R. A new weapon for memory power: Elephantopus scaber (Linn.). Int J Nutr Pharmacol Neurol Dis 2014;4:64-8

How to cite this URL:
Sahoo HB, Mandal PK, Bhattamisra SK, Bhaiji A, Sagar R. A new weapon for memory power: Elephantopus scaber (Linn.). Int J Nutr Pharmacol Neurol Dis [serial online] 2014 [cited 2017 Jun 27];4:64-8. Available from: http://www.ijnpnd.com/text.asp?2014/4/1/64/124616


   Introduction Top


Poor memory power, lower retention, and slow recalling are common problem in today's stressful and competitive world. Ageing and continuous stress or emotions are the basic key for cognitive dysfunctions like memory loss, amnesia, anxiety, schizophrenia, Alzheimer's disease, etc. [1] An epidemiological study reveals that dementia or memory loss is a major hidden problem in Indian populations. [2] The rate of dementia increases exponentially with increasing age. [3],[4] Aging process is associated with a slow decline of sensory and motor performances in the brain. This decline in sensory and motor performance has been attributed to the accumulation of oxidative damage to lipids, proteins, nucleic acids, [5],[6],[7]] and imbalance of various neurotransmitter levels due to oxidative stress in both aged humans and rodents. [8],[9],[10] Among all these neurotransmitters, the cholinergic function is mainly responsible for the memory disorders due to age-related decline of acetylcholinesterase (AChE) activity in various cerebral areas [11] and synaptic plasma membranes. Progressively decline of AChE activity is due to chronic attack of free radicals and oxidative stress. [12] Therefore, various antioxidant supplements and flavonoidal components might be beneficial for preserving brain functions and forestalling the age-related deficits. [13]

Elephantopus scaber Linn. commonly known as Elephant's foot, (Asteraceae) is a scabrescent aromatic herb distributed in the moist deciduous forests of central Western Ghats. According to the traditional claims, the roots were used as an antipyretic, cardiotonic, dysuria, diarrhea, dysentery, stomachic pain, and diuretic. The leaf extract had already been evaluated for diuretic, [14] anti-inflammatory, [15] hepatoprotective effect, [16] and also treatment for eczema and ulcers. Preliminary qualitative phytochemical screening of ethanolic extract of E. scaber showed the presence of flavonoids, phenols, steroids, tannins, terpenes, xanthoproteins, and sugar. [17] The biological actions of flavonoids within the nervous system are to enhance neuronal function, stimulate neuronal regeneration, control neuronal resistance to neurotoxins, including oxidants and inflammatory mediators and also responsible for neuronal differentiation, long-term potentiation, and memory. [18] It is postulated that anti-inflammatory and antioxidant drugs are useful in controlling the progression and inflammatory damage to brain tissue in Alzheimer's disease. [19] The leaves of the plant are commonly used in Ayurvedic medicine for the improvement of memory deficit. [20],[21] E. scaber has both antinflammatory and antioxidant effect and it is a rich source of flavonoid content. On the basis of above-mentioned scientific evidences, the present study was undertaken to investigate the memory enhancing activity from ethanolic extract of E. scaber leaves (EESL).


   Materials and Methods Top


Plant material

The fresh leaves of E. scaber were collected from local area of Bhopal, India. The material was identified and authenticated by Dr. M. Rajpoot, Senior Botanist, Department of Botany, Jiwaji University, Gwalior, MP, India.

Extract preparation

The leaves of E. scaber were air dried and reduced to coarse powder. The extract was prepared by taking 100 g coarse powder and macerated with ethyl alcohol for 48 h. Then the residue was filtered by Whatman filter no. 4 and filtrate was evaporated under reduced pressure by rotary vacuum evaporator to obtain dried extract (extractive value 9.28% w/w). The dried extract was freeze dried and stored at 4΀C until use.

Chemicals

5,5-dithiobis-2-nitrobenzoic acid (DTNB), acetylcholine iodide, serine salicylate, sodium dihydrogen phosphate (Hi-media, India), and piracetam (Vetranal) were procured. All the other chemicals were of analytical grade.

Experimental animals

Male Swiss albino mice aged (12-15 months) weighing around 30-40 g were housed in standard conditions of temperature (22 ± 2΀C), relative humidity (55 ± 5%), and light (12 h light/dark cycles) were used for the study. They were fed with standard pellet diet (Lipton, India) and water ad libitum. The animals had fasted for 24 h, prior to the study. The experimental protocol was approved by Institutional Animal Ethical Committee of the Institute.

Treatment schedule and group design

Previous study claimed that, E. scaber did not produce any toxicity symptoms up to the dose of 6,000 mg/kg. [17] The dose selection for memory activity was 150, 300, and 600 mg/kg of E. scaber leafy extract. Healthy male aged mice were divided into five groups with six mice in each. Group I served as control, Group II treated with standard drug as piracetam (400 mg/kg/i.p.) and Groups III, IV, and V were treated with the tested extract of 150, 300, and 600 mg/kg of E. scaber, respectively with daily administration for 15 days. All doses of EESL were administered orally; whereas, the standard drugs were administered intraperitoneally. The volume of oral administration and i.p. injection were 1 ml/100 g of mouse.

Elevated plus maze test

Elevated plus-maze served as the exteroceptive behavioral model to evaluate memory in mice. The apparatus consisted of two open arms (16 cm Χ 5 cm) and two closed arms (16 cm Χ 05 cm Χ 12 cm) that extended from a common central platform (05 cm Χ 05 cm). The entire maze was elevated to a height of 25 cm above the floor level. After 15 th day of drug treatment, each mouse was placed at the end of an open arm, facing away from the central platform. Transfer latency (TL) was recorded after 15 th day of drug treatment for each group and compared to control group. [22] TL was the time (in seconds) taken by the animal to move from the open arm into any one of the covered arms with all its four legs. The reduction in TL value of retention indicated improvement in memory.

Passive avoidance test

The passive avoidance behavior test based on negative reinforcement was used to examine the long-term memory. The apparatus consists of a box (27 cm Χ 27 cm Χ 27 cm) having three walls of wood and one walls of Plexiglas, featuring a grid floor (made up of 3 mm stainless steel rods set 8 mm apart), with a wooden platform (10 cm Χ 7 cm Χ 1.7 cm) in the center of the grid floor. The box was illuminated with a 15 W bulb during the experimental period. Electric shock (20 V, A.C.) was delivered to the grid floor. Training period (15 th day of drug treatment) was carried out in two similar sessions. Each mouse was placed on the center of the grid floor. When the mouse stepped down with all the paws on grid floor, shocks were delivered for 15 s and the step-down latency (SDL) was measured. [23] SDL was recorded after 15 th day of drug treatment for each treated group and compared to control group as passive avoidance behavior for each trial.

Collection of brain sample

After 15 th day of administration, the animals of all groups were sacrificed by cervical decapitation under light anesthesia after 90 min of the last dose. The whole brain (minus the cerebellum) was removed carefully from the skull and transferred to a glass homogenizer. The fresh whole brain homogenized in an ice bath with 10 volumes of normal saline injection. The homogenate was centrifuged at 3,000 rpm for 10 min and the pellets were re-extracted with an equal volume of 30 mM Na 2 HPO 4 , pH 7.6, containing 1% Triton X-100 and the suspensions were centrifuged for 2 h. The resultant supernatant was used for the estimation of brain cholinesterase, whereas the pellet for caspase-3 estimation. For estimation of cholinesterase and caspase-3 activity, acetylthiocholine iodide and acetyl-Asp-Glu-Val-Asp-p-nitroanilide (Ac-DEVD-pNA) were taken as substrate respectively by colorimeter. The AChE activity was expressed as mmol/min/g of tissue protein whereas caspase-3 was expressed as nmol/h/mg of protein. [24],[25],[26]

Statistical analysis

Data were expressed as mean ± standard error of the mean (SEM) of the groups and analyzed by one-way analysis of variance (ANOVA) followed by the Tukey's test for multiple comparisons and Dunnett's tests where the P > 0.05 and 0.01 was considered to be statistically significant.


   Results Top


Effect of EESL on TL and SDL in aged mice

EESL (150, 300, and 600 mg/kg, p.o.) showed dose-dependent effect in TL as well as SDL after 15 th day of treatment in aged mice as shown in [Table 1]. But EESL (300 and 600 mg/kg, p.o.) showed highly significant reduction (P > 0.05 and P > 0.01) in TL; whereas, significant increase in SDL (P > 0.01) as compared to control groups in aged mice, which indicates improvement in memory activity of EESL.
Table 1: The transfer latency (Elevated plus maze test) and step down latency (Passive avoidance paradigm test) by the treatment of EESL and piracetam in aged mice after 15th day of treatment

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Effect of EESL on cholinestrase and caspase-3 activity

EESL (300 and 600 mg/kg, p.o.) and piracetam (400 mg/kg/i.p.) as standard showed a remarkable reduction in brain cholinesterase activity in aged mice, as compared to control group as shown in [Figure 1]. But, EESL (600 mg/kg, p.o.) showed highly significant (P > 0.05) reduction of brain cholinesterase activity in aged mice after 15 th day of treatment. In case of caspase-3 estimation, comparison of EESL with the control group also showed a statistically significant increase (P > 0.01) of caspase-3 level in aged mice as shown in [Figure 2].
Figure 1: Effect of ethanolic extract of Elephantopus scaber (Linn.) leaves (150, 300, and 600 mg/kg/p.o.) on cholinesterase activity in aged mice after 15th day of drug treatment. Each value represented as mean ± standard error of the mean of six mice. (*P<0.05, **P<0.01 vs. control). Piracetam was used as standard

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Figure 2: Effect of EESL on caspase-3 level in aged mice brain. Each value represented as mean ± SEM of six mice. *P<0.05, **P<0.01 vs. control

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   Discussion Top


Aging is characterized by an impairment of cognitive function, including learning and memory. The regulation of memory function depends upon the level of neurotransmitter such as ACh, serotonin, catecholamine, [27] GABA, [28] and glutamate. [29] The inhibitory effects of cholinesterase act as memory enhancement by increasing the ACh level and decreasing dopamine level. [30],[31],[32] Alzheimer's disease or dementia is closely related to the reduction of ACh levels in the brain. [33],[34] ACh shows memory enhancing activity due to stimulation of extracellular signal-regulated kinase (ERK) by ACh receptor. [35] In the present investigation, the TL in elevated plus maze paradigm and SDL in passive avoidance paradigm was widely utilized for testing age-related memory impairments in Swiss mice. The observed behavioral results using elevated plus maze test and passive avoidance test showed that EESL 600 mg/kg for 15 days was showed significantly higher than control group during acquisition and retention of memory. It does clearly indicate that oral administration of EESL has enhanced the learning and retrieval ability of previously acquired information providing additional support to the earlier reports. In our present study, E. scaber (600 mg/kg) possesses highly significant inhibition of cholinesterase, which indicates increase level of ACh in brain.

The increase in antioxidant and caspase-3 level in the brain is an indication of the memory enhancing activity. The increase in caspase-3 activity level is mainly due to presence of carotenoids. [24] In our observation, EESL was showed remarkable increase of caspase-3 level in brain of mice, may be due to presence of this constituent. A combination of anti-inflammatory, antioxidant, neuroprotective role, and presence of terpenoids and phenolic compounds could all be leading to net improvement of memory activity. [36],[37] Dietary supplementation with polyphenols, carotenoids, flavonoids, and n-3 fatty acids exerts beneficial effects not only through the scavenging of free radicals, but also by modulating signal transduction, gene expression, and restoring optimal neuronal communication. [38]


   Conclusion Top


In conclusion, the EESL possesses significant improvement in memory, anticholinesterase, and caspase activity. These collective pharmacological actions attributed by E. scaber leafy extract may serve as beneficial and supporting agent in the treatment of cognitive disease as brain tonic. Despite the above facts that the exact mechanisms underlying for memory activity are still unknown, therefore more pharmacological and neurochemical research require to establish any new therapeutic advantages.


   Acknowledgment Top


The authors would like to kindly acknowledge Prof. R. Sagar for his valuable guidance and cooperation throughout the work. We are thankful to Dr. M. L. Kori (Director) of Vedica College of Pharmacy, RKDF University, Bhopal, MP, India for providing the lab facilities and financial assistance to fulfill our research work.

 
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