Positive modulation of cognition and mood in the healthy elderly volunteer following the administration of Centella asiatica

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Abstract

Aims of this study

Centella asiatica has a reputation to restore decline cognitive function in traditional medicine and in animal model. However, little evidence regarding the efficacy of Centella asiatica from systematized trials is available. Therefore, the present randomized, placebo-controlled, double-blind study investigated the effect of Centella asiatica on cognitive function of healthy elderly volunteer.

Materials and methods

Twenty-eight healthy elderly participants received the plant extract at various doses ranging 250, 500 and 750 mg once daily for 2 months. Cognitive performance was assessed using the computerized test battery and event-related potential whereas mood was assessed using Bond–Lader visual analogue scales prior to the trial and after single, 1 and 2 months after treatment.

Results

The results showed that the high dose of the plant extract enhanced working memory and increased N100 component amplitude of event-related potential. Improvements of self-rated mood were also found following the Centella asiatica treatment.

Conclusion

Therefore, the present findings suggest the potential of Centella asiatica to attenuate the age-related decline in cognitive function and mood disorder in the healthy elderly. However, the precise mechanism(s) underlying these effects still require further investigation.

Introduction

During aging, a gradual deficit is present with regard to cognitive functions, which normally does not severely disturb the daily life activities related to the physical, mental, or social functioning in elderly adults. The age-related cognitive decline has been characterized as a diminution of attentional processes, episodic and working memory, and processing and psychomotor speed (Nolan and Blass, 1992, Salthouse, 1994, Earles and Salthouse, 1995, Grady and Craik, 2000, Christensen, 2001). However, this condition can eventually progress to clinically recognizable dementia (Chen et al., 2005, Amieva et al., 2005). Previous studies have demonstrated that age-related impairment in working memory is accompanied by the alteration of the event-related potential in respond to the auditory oddball tasks, a most frequent parameters examined in psychophysiological studies of cognitive aging (Bashore et al., 1989). It was found that the latencies of P300 and N100 components increased (Oken and Kaye, 1992, Kugler et al., 1993, Anderer et al., 1996) whereas the amplitudes of these two components were decreased (Coyle et al., 1991, Nordin et al., 1999).

Recently, numerous studies have suggested that the age-related cognitive decline can be prevented (Solfrizzi et al., 1999). Therefore, a new approach aimed at controlling the decrease in cognitive function was focused. Numerous previous studies had demonstrated that fruits, vegetables and medicinal plants could prevent the occurrence of the neurochemical and behavioral changes that occurred in aging (Veerendra Kumar and Gupta, 2002, Joseph et al., 2003, Goyarzu et al., 2004).

Centella asiatica (L) urban, a creeping plant in a family of Apiaceae, is found almost all over the world including in China, India and Thailand. This plant is claimed to be benefit for managing the central nervous system disorders, skin and gastrointestinal disorders (Subathra et al., 2005). In addition, Centella asiatica is also claimed to possess memory enhancing effect (Veerendra Kumar and Gupta, 2002), anti-inflammatory (Suguna et al., 1996), wound healing (Suguna et al., 1996), anticancer (Babu et al., 1995) and antioxidant properties (Zainol et al., 2003). Recently, Centella asiatica products are widely available in market as cognitive booster. However, supported document with valid biological data is still very limited. Therefore, the current study is carried out to determine the effect of Centella asiatica on the cognitive function and mood in the elderly.

Section snippets

Participants

Four male, and twenty-four female healthy elderly volunteers (mean age 65.05 ± 3.56 years) were recruited to participate in this study. The Ethical Committee of Faculty of Medicine, Khon Kaen University, have approved the study, and all subjects gave written informed consent. Prior to participation, each volunteer signed an informed consent form and completed a medical health questionnaire. All subjects were also undergone extensive medical evaluation in order to ascertain subject suitability for

Characteristics of subjects

The baseline data about characteristic of subjects in all groups were shown in Table 1. No significant difference of all parameters among various groups was observed.

Event-related potential components (ERP)

The effects of Centella asiatica on ERP components were shown in Table 2. The pre-dose baseline data of latency and amplitude of both N100 [F(3,28) = 0.9068, p = 0.4503; F(3,28) = 1.0372, p = 0.3913] and P300 [F(3,28) = 1.7785, p = 0.1741; F(3,28) = 1.1192, p = 0.3580] showed no significant difference. After 2 months of treatment with Centella

Discussion

The present study investigated the effect of Centella asiatica extract on the cognitive performance and mood in the elderly. The results from this study suggest that the ingestion of single dose of Centella asiatica can modulate only the reaction time of spatial memory and %accuracy of numeric working memory in the healthy elderly.

Recently, it was found that the numeric working memory process involved the function of lateral prefrontal cortex (PFC) (D’Esposito et al., 1999, Smith and Jonides,

Acknowledgements

This study was supported by Faculty of Medicine, Center for Research and Development of Herbal Health Product and Graduate School, Khon Kaen University. Moreover, gratitude was also extends to the Cognitive Drug Research Company who first developed the CDR battery test.

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