About Herbs

Bottom Line: Schisandra has not been shown to treat cancer.

Schisandra is a fruit extract used in traditional Chinese medicine. Scientists do not know how Schisandra works, but laboratory experiments have begun to identify some of its biological activities.

Schisandra has antioxidant activity, which means that it neutralizes free radicals that can cause cellular and genetic damage. When tested in animals, schisandra had the following effects: 1) an increase in contractility of the heart 2) an increase in contractions of the uterus 3) faster breathing rate 4) and an increase in the level and activity of an important detoxifying compound, glutathione, in the liver.  Schisandra also appears to affect the central nervous system of rats, but the exact effects have not been elucidated yet. One extract of schisandra was able to inhibit the activity of HIV in the test tube, but this effect has not been tested in animals or humans.

No clinical trials have tested whether schisandra has biological effects in humans, or whether it is safe to take for long periods of time.

Wu wei zi, schizandra, five flavor berry, fructus schisandra, gomishi, omicha, ngu mie gee

Derived from the fruit of the plant. This herb is used in traditional Chinese medicine for cough, wheezing, diarrhea and spontaneous sweating ⁽¹⁾.  It is also used as an adaptogen. Various lignans are believed responsible for the activity of schisandra, but limited research evaluates its mechanism of action. In animal models, schisandra protects the liver against various toxins (e.g. menadione) ⁽⁷⁾, prolongs pentobarbital sleep time ⁽⁸⁾, and increases cardiac contractility without affecting blood pressure ⁽¹⁰⁾. In vitro studies have shown that schisandra has protective effects against adriamycin-induced cardiotoxicity ⁽¹¹⁾.  No human trials have been performed with this supplement. Although no drug interactions are reported, schisandra may induce cytochrome P450 and affect other metabolic pathways ^{(5) (9)}. No common adverse events are reported ⁽¹⁰⁾. Additional research is necessary to understand the efficacy and to uncover possible interactions associated with this supplement.

The mechanism of action is unknown. Schisandra has antioxidant activity. Animal studies suggest that water- and alcohol-based extracts promote myocardial contractility without effects on blood pressure, stimulate the respiratory center, induce uterine smooth muscle contractions, and increase hepatic glutathione levels and the activities of glucose-6-phosphate and glutathione reductase ⁽⁴⁾. Protection from hepatotoxicity and improvements in phase I metabolism are documented in rats administered 1 ml/kg carbon tetrachloride 24 hours after exposure to schisandra extract ^{(5) (9)}. Schisandra extract appears to increase DT-diaphorase activity within rat hepatocytes resulting in protection from menadione-induced toxicity ⁽⁷⁾. In rats, repeated administration of schisandra extract at 10 mg and 25 mg doses reduces the extent of cycloheximide-induced amnesia ⁽⁶⁾. Nigranoic acid, a triterpenoid extract from schisandra plants stems, shows limited activity against HIV-1 reverse transcriptase in vitro at an IC50 of 200 mcg/ml ⁽³⁾. Schisandrin B and schisandrol B have variable effects on pentobarbital-induced sleep in mice: 12.5 mg/kg prolongs sleep while 100 mg/kg shortens the sleep interval. Schisandrin C increases pentobarbital sleep period at all doses ⁽⁸⁾.

No formal pharmacokinetic studies have been performed. Animal data suggests that schisandra increases metabolism via induction of cytochrome P450 and/or glutathione reductase pathway ⁽¹⁾.

CNS depression ⁽²⁾, Heartburn ⁽¹⁰⁾. 

No significant drug interactions have been reported, but schisandra may induce cytochrome P450 and other hepatic metabolic pathways ⁽¹⁾.

Lower AST, ALT, Alkaline phosphate.

There are no noteworthy studies.