Magnolol Decreases Body Temperature by Reducing 5 Hydroxytryptamine Release in the Rat Hypothalamus

Abstract

1. The effects of magnolol, isolated and purified from the cortex of Magnolia officinalis Rehd. et Wils, on thermoregulation and hypothalamic release of 5-hydroxytryptamine (5-HT) by in vivo microdialysis were assessed in normothermic rats and in febrile rats treated with interleukin-1 beta. 2. Intraperitoneal administration of magnolol (25-100 mg/kg) produced a decrease in colon temperature, an increase in foot skin temperature, a decrease in metabolic rate and a decrease in the endogenous release of 5-HT in the rat hypothalamus. 3. Depletion of rat brain 5-HT, produced by intracerebroventricular pretreatment with 5,7-dihydroxytryptamine, attenuated the magnolol-induced hypothermia, cutaneous vasodilation and decreased metabolism. 4. Intracerebroventricular administration of (+/-)-2,5-dimethoxy-4-iodoamphetamine (a 5-HT2 receptor agonist; 5-10 micrograms/5 microL) increased basal colon temperature and reversed the magnolol-induced hypothermia. 5. The increases in both colon temperature and hypothalamic 5-HT release produced by interleukin-1 beta injection were attenuated by treatment with magnolol. 6. The data suggest that magnolol decreases body temperature (due to increased heat loss and decreased heat production) by reducing 5-HT release in rat hypothalamus.

Behavioral and biochemical studies on chronic mild stress models in rats treated with a Chinese traditional prescription Banxia-houpu decoction

“…The lectin from Pinellia ternate raise [Ca 2 + ]i by promoting Ca 2 + influx, and then facilitate neurotransmitter release (Shi et al, 1994). Magnolol and honokiol are known central nervous system depressants which can modulate central serotonergic activity (Hsieh et al, 1998;Kuribara et al, 1998;Tsai et al, 1995). Magnolol and honokiol are also reported to inhibit MDA production in rat heart mitochondria (Lo et al, 1994).…”

Combined administration of the mixture of honokiol and magnolol and ginger oil evokes antidepressant-like synergism in rats

“…In the previous experimental studies, we found that Banxia-Houpu decoction exhibited antidepressant-like properties via regulation of the central neurochemical and immune responses in well-validated models of depression in rodents (Li et al, 2003a,b;Guo et al, 2004;Zhang et al, 2004;Wang et al, 2005). Honokiol and magnolol, the major constituents simultaneously identified in magnolia bark (Teng et al, 1988), are considered to be central nervous system depressants that modulate the central serotonergic activity (Tsai et al, 1995;Hsieh et al, 1998;Kuribara et al, 1998). Our previous study also confirmed that the mixture of honokiol and magnolol (HMM) were the active principles responsible for antidepressant activity of magnolia bark .…”

Evaluation of short-term and subchronic toxicity of magnolia bark extract in rats

“…MBE is consumed for the relief of menopausal symptoms, for increasing metabolism, and for reducing cortisol levels. Historically, magnolia bark has been used for many years as a component of traditional Chinese medicines and Japanese remedies for the treatment of depression, anxiety, nervous disorders, gastrointestinal disturbances, asthma, and stroke, as well for the alleviation of headaches, muscular pain and fever (Hattori et al, 1986;Tsai et al, 1995;Ogata et al, 1997;Sarker, 1997;Hsieh et al, 1998;Maruyama et al, 1998). The mechanism for the purported biological activity of MBE is unclear; however Homma et al (2000) and Hsu et al (2004) have reported that magnolol (the main constituent of MBE) can reduce eicosanoid mediator levels, and the anti-inflammatory and anti-asthmatic effects may be related to MBE's antibacterial activity (Bensky and Gamble, 1993).…”