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Phytomedicine. 2018 Mar 15;42:180-189. doi: 10.1016/j.phymed.2018.03.042. Epub 2018 Mar 19.

Polygonum aviculare L. extract reduces fatigue by inhibiting neuroinflammation in restraint-stressed mice.

Author information

1
Division of Herbal Research, Korea Institute of Oriental Medicine (KIOM), 1672, Yuseong-daero, Yuseong-gu, Daejeon, 305-811, South Korea; Department of Korean Medicine, Dongguk University, 30, Pildong-ro, Jung-gu, Seoul, 04620, South Korea.
2
Division of Herbal Research, Korea Institute of Oriental Medicine (KIOM), 1672, Yuseong-daero, Yuseong-gu, Daejeon, 305-811, South Korea.
3
Division of Future Medicine, Korea Institute of Oriental Medicine (KIOM), 1672, Yuseong-daero, Yuseong-gu, Daejeon, 305-811, South Korea.
4
Department of Korean Medicine, Dongguk University, 30, Pildong-ro, Jung-gu, Seoul, 04620, South Korea.
5
Division of Herbal Research, Korea Institute of Oriental Medicine (KIOM), 1672, Yuseong-daero, Yuseong-gu, Daejeon, 305-811, South Korea. Electronic address: hkkim@kiom.re.kr.

Abstract

BACKGROUND:

Chronic fatigue patients experience various neuropsychological symptoms, including fatigue behaviors, chronic pain, and depression. They also display immune system dysregulation. Polygonum aviculare L. extract (PAE) is a traditional herbal medicine used to treat inflammatory diseases by reportedly decreasing pro-inflammatory cytokine production.

HYPOTHESIS/PURPOSE:

We hypothesized that the anti-inflammatory properties of PAE would attenuate fatigue symptoms in a mouse model of restraint stress.

STUDY DESIGN:

We evaluated the effects of PAE on fatigue using three experimental groups: unstressed, vehicle-treated stressed, and PAE-treated stressed mice. This restraint stress paradigm, comprised of restraint for 3 h daily for 15 days, was used to model chronic fatigue.

METHODS:

We compared lethargy-like behavior between our experimental groups using forced-swim, sucrose preference, and open-field tests once per week on days 7 and 14 of restraint stress. We also used histology and western blotting to evaluate pro-inflammatory cytokine expression in the brain and serum, and microglial activation in the brain. Finally, we used liquid chromatography/mass spectroscopy (LC/MS) to identify individual components of PAE, and applied cell culture techniques to test the effects of these components on neuronal cells in vitro.

RESULTS:

In restraint-stressed mice, PAE treatment decreased lethargy-like behavior relative to vehicle-treated animals. PAE treatment also reduced expression of fatigue-related factors such as corticosterone, serotonin, and catecholamines (adrenaline and noradrenaline) in the brain and serum, and decreased expression of CD68, Ibal-1, and the inflammatory cytokines TNF-α, IL-6, and IL-1β in the brain. Together, these data indicate that PAE reduced fatigue and is anti-inflammatory. Furthermore, histopathological analyses indicated that PAE treatment recovered atrophic volumes and hepatic injuries. Finally, LC/MS analysis of PAE identified four individual chemicals: myricitrin, isoquercitrin, avicularin, and quercitrin. In neuronal cell cultures, treatment with these PAE components inhibited TNF-α production, confirming that PAE treatment reduces neuroinflammation.

CONCLUSIONS:

PAE treatment may reduce fatigue by suppressing neuroinflammation and the expression of fatigue-related hormones.

KEYWORDS:

Fatigue; Mibyeong; Polygonum aviculare L.; Restraint stress; Stress

PMID:
29655685
DOI:
10.1016/j.phymed.2018.03.042
[Indexed for MEDLINE]

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