Schisandra: benefits, dosage, contraindications

Adaptogen

In Traditional Chinese Medicine, schisandra is considered an adaptogen and is prescribed with other herbs to increase resistance to physical stressors and emotional stressors and to improve allostasis. nnIn animal research, schisandra reduces the increase in heart rate during exercise, resulting in decreased fatigue and improved performance as well as enhanced endurance. The mechanisms of these effects are not yet known. nnPGC-1α, a major regulator of mitochondrial biogenesis, appears to be a candidate for interacting with schisandra to promote more efficient physical exertion, but further studies on this subject are needed. nn

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Anti-inflammatory

In vitro, schisandrin inhibits the production of nitric oxide (NO), the release of prostaglandin E2, cyclooxygenase-2 and nuclear factor kappa B (NF-κB). nnIn vitro and in vivo studies have identified anti-inflammatory activity for gomisin A, gomisin J, wuweizi C, schisandrin B, schisandrin C, gomisin N and schisandrin derivatives. Several schisandra lignans, including gomisin N and schisandrol A, have shown potent inhibition of the nuclear factor of activated T cells in vitro. nn

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Hepatoprotective

In vitro and in vivo studies have shown hepatoprotective effects with schisandra against carbon tetrachloride toxicity and mercuric chloride toxicity. Research on schisandrin B suggests that it is the main constituent responsible for these beneficial effects. Further investigation reveals that schisandrin B increases the effectiveness of the hepatic glutathione antioxidant system, thereby inhibiting carbon tetrachloride-induced lipid peroxidation. However, additional mechanisms appear likely. More recently, whole Schisandra fruit extract has been shown to induce glutathione S-transferases in vitro. In addition, it has been found that several lignans induce the expression of phase II detoxification enzymes in vitro, a factor considered important in the prevention of liver cancer.

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Antioxidant

Seven lignans isolated from Schisandra have shown stronger antioxidant activity than vitamin E at the same concentrations. Schisanhenol appears to have the most significant effects. Schisandra berry essential oil has also demonstrated antioxidant activity.

Anticancer

In vitro, Schisandra extracts and several isolated constituents have demonstrated anticancer activity against various cancer cell lines, including leukemia, breast, liver, stomach, colon, and lung cancers. The mechanisms of action are generally related to the induction of apoptosis, protection of nucleic acids, and the excretion of the carcinogen.

Antiallergic

Schisandra has shown various antiallergic effects, including inhibition of eosinophil recruitment in pulmonary epithelial cells in vitro and a reduction in the severity of atopic dermatitis in vivo. In vivo, schizandrine has shown significant anti-asthmatic activity via inhibition of eosinophil accumulation in the airways, reduction of IL-4, IL-5, interferon-γ and TNF-α levels in bronchoalveolar lavage fluid, reduction of oxidative stress, and inhibition of infiltration of inflammatory cells into lung tissue.

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Antihistamine

Schisandra has shown various antiallergic effects, including inhibition of eosinophil recruitment in pulmonary epithelial cells in vitro and a reduction in the severity of atopic dermatitis in vivo. In vivo, schizandrine has shown significant anti-asthmatic activity via inhibition of eosinophil accumulation in the airways, reduction of IL-4, IL-5, interferon-γ and TNF-α levels in bronchoalveolar lavage fluid, reduction of oxidative stress, and inhibition of infiltration of inflammatory cells into lung tissue.

Neurological

Schizandrin and schisandrin B inhibit lipopolysaccharide-induced microglial activation and significantly ameliorate neuronal cell death in vitro and in vivo by inhibiting the microglia-mediated neurotoxic inflammatory response. Microglial activation is involved in the pathophysiology of Alzheimer’s and Parkinson’s diseases. It has also been shown that schisandrin B has a neuroprotective effect in a rat model of transient focal cerebral ischemia and that it improves brain antioxidant status. In vivo, pretreatment with schisandrin B prevented oxidative stress induced by scopolamine (an atropine-like parasympatholytic that acts as a competitive antagonist of acetylcholine) and the impairment of learning and memory. Schisandrin B appears to reduce the acetylcholinesterase activity induced by scopolamine and thus maintain normal acetylcholine levels.

Hypoglycemic

In vitro studies indicate that Schisandra has antidiabetic activity. It was found that various lignans improve basal glucose uptake by hepatic cells, particularly gomisin N. Moreover, in vivo studies show that Schisandra extracts reduce blood glucose, improve lipid metabolism, increase liver glycogen content and polydipsia in diabetic mice. In addition, aqueous Schisandra extracts reduced postprandial blood glucose in rats via inhibition of alpha-glucosidase and alpha-amylase, enzymes responsible for monosaccharide absorption in the small intestine.