(1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA) is a β-carboline indole alkaloid naturally occurring in plants, foods, insects, and endogenously in mammals and humans. It exerts antioxidant and antithrombotic properties. MTCA is thought to be a possible causative substance of eosinophilia-myalgia syndrome associated with ingestion of L-tryptophan.

Gomisin N is the most abundant dibenzocyclooctadiene lignan present in the traditional Chinese medicinal herb Schisandra chinensis (Turcz.) Baill. In vitro assays demonstrated that Gomisin N could inhibit TGF-β induced epithelial-mesenchymal transition of 4T1 cells and of primary human breast cancer cells. Gomisin N could maintain membrane stability of rat hepatocytes under oxidative stress. Gomisin N can reduce inflammation, inhibit apoptosis, and improve cardiac function after ischemic injury. It represents a potential novel therapeutic approach for treatment of ischemic heart disease. Gomisin N produced beneficial sedative and hypnotic bioactivity, which might be mediated by the modification of the serotonergic and GABAergic system.