Elsevier

Phytomedicine

Volume 17, Issue 10, August 2010, Pages 794-799
Phytomedicine

Potential antidepressant properties of Radix Polygalae (Yuan Zhi)

https://doi.org/10.1016/j.phymed.2010.01.004Get rights and content

Abstract

Radix Polygalae (“Yuan Zhi”, the roots of Polygala tenuifolia Willd., YZ) is an important herb used in traditional Chinese medicine to mediate depression. The present study was designed to verify the antidepressant effects of the standardized YZ ethanol extract (YZE) and its four fractions YZ-30, YZ-50, YZ-70 and YZ-90 on the tail suspension (TST) and forced swimming test (FST). Furthermore, the standardization of the fractions obtained from the separation procedures was carried out by high-performance liquid chromatography (HPLC)-fingerprint. The YZ-50 fraction (Oligosaccharide esters –enriched, oral (200 mg/kg) showed a significant anti-immobility like effects. The data of YZ-50 on the corticosterone-induced injure of SH-SY5Y human neuroblastoma cell indicated that YZ-50 may have biological effects on neuroprotection. Proliferation of cell lines was assessed by dimethylthiazoldiphenyltetrazoliumbromide (MTT) and 5-bromo-2′-deoxyuridine (BrdU) incorporation assays. It was found that YZ-50 and its two bioactive compounds, 3,6′-di-o-sinapoyl-sucrose (DISS) and tenuifoliside A(TEA) showed protection activities in SY5Y cells from the lesion. By using bioassay-screening methods, our results indicate that the presence of oligosaccharide esters such as DISS and TEA in this herb may be responsible for the cytoprotective activity effects.

Introduction

Depression is one of the major mental disorders associated with symptoms such as regular negative moods, decreased physical activities, feelings of helplessness, and sluggish thought and cognitive function (Rudy, 2004). Selective and reversible monoamine oxidase inhibitor (e.g., moclobemide), selective serotonin reuptake inhibitors (e.g., citalopram) or serotonin and noradrenaline reuptake inhibitors (e.g., venlafaxine) are the typical antidepressants usually used. However, most of the drugs are synthetic nitrogen-bearing compounds which have inevitably some serious adverse-effects such as causing cardiovascular disease, narrowing the scope of remedial spectrum and shortening of t1/2. Hence, there is an urgent need for the research and development of more effective antidepressants without any (or with minor) adverse-effect (Chen et al., 2004).

According to the theory of the traditional Chinese medicine (TCM), the clinical condition of depression could be mainly classified into sentiment and mental inquietude (asthenia syndrome). The symptom of asthenia syndrome can be described as mental stress, loss of memory, sorrowful, emotion unrest, or discomfort. Based on this view point, many Chinese medicinal plants have been successfully used to treat sentimental diseases, which is similar to depression in the Western medicine. Moreover, active principles from them were extracted and isolated (Yu et al., 2002; Xia et al., 2007; Rocha et al., 2007).

Radix Polygalae is the dried root of Polygala tenuifolia Willd, which has been used as a traditional medicine for expectorant, tonic, tranquillizer and antipsychotic agent etc. (Chung et al., 1992; Huang, 1993). Radix Polygalae is classified as a high grade herb in the “Shennong’s Herbal”, and was widely used in the vast majority of Chinese medicine prescription to treat mental diseases, for example, amnesia, neurasthenia, palpitation, and insomnia (Chang and But, 1986). Chemically, the dried root of this plant contains polygalitol, tenuigenin, polygalasaponin, oligosaccharides (Ikeya et al., 2004) and xanthone derivatives.

In this study, the mice despair models were used for screening of the antidepressant fractions and substances obtained from Polygalae Radix (YZ), accompanied with the phytochemical analysis by HPLC. The present study was designed to verify the promote effect of the YZ-50 on hippocampal neurogenesis. Considering major antidepressant drug have the ability for neuroprotection pain, we have used corticosterone-induced injure cell model to screen cytoprotective and anti-depressant effects of fractions and substances which obtained from Radix Polygalae.

Section snippets

Plant material

Radix Polygalae were purchased from traditional Chinese medicinal (TCM) pharmacy, Chinese People’s Liberation Army (PLA) General Hospital (Beijing, China) and authenticated by Professor LIU Ping, TCM pharmacy, PLA General Hospital. A voucher specimen (NU-80617) has been deposited in the Herbarium of PLA General Hospital. The quality of these crude drugs was controlled and processed according to the Chinese Pharmacopoeia (Zheng, 2005).

Preparation of the extracts

The air-dried Radix Polygalae (965.27 g) was powered and

Tail suspension test

The tail suspension test was based on Steru’s method (Steru et al., 1985). Briefly, the mouse was individually suspended by the tail with a clamp (2 cm from the end) for 6 min in a box (25×25×30 cm) with the head 5 cm above the bottom. 8-12 animals were used for the preliminary activity screening test, carried out in a darkened room with minimal background noise. Half an hour after administrating the test sample, the duration of immobility (counting by seconds) were evaluated at 2 different doses

HPLC fingerprint

HPLC analysis has shown the presence of 3′,6-di-o-sinapoyl-sucrose(DISS) and tenuifoliside A(TEA), at retention time of 30.567 min and 33.717 min (purity >90%), and DISS and TEA were employed as the standard for quality control in the active fraction. Chromatographies of different extracted fractions were shown in Fig. 2A-F. Fig. 2C showed that some unknown compounds in polarity were difficult to separate and these may be compounds which can not be detected under this condition of HPLC.

Effect of different fractions on the duration of immobility in TST and FST in mice

The

Discussion

The TST and FST were the most widely-accepted models for assessing antidepressant-like activities in mice. The immobility shown in these two tests is suggested to reflect a state of ‘behavioral despair and variants’ or ‘failure to adapt to stress’ (Wilner, 1997; Borsini and Meli, 1998). These two models are widespread in the laboratory mainly due to their ease-of-use, consistency across laboratories, and their ability to detect a broad spectrum of antidepressant agents.

The Radix Polygalae was

Acknowledgements

This research was supported by the National Natural Science Foundation of China (No. 90209036). We were indebted to Professor TU Peng-Fei, School of Pharmacy, Beijing University, for giving some pure compounds.

References (17)

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