Isatin is an indole derivative found in Isatis, Calanthe, and Couroupita that exhibits anti-inflammatory, antioxidative, neuromodulatory, and anticancer chemotherapeutic activities. Isatin prevents TNBS-induced increases in TNF-α, COX-2, and PGE2 levels as well as decreases in SOD and GSH levels, protecting against colitis-induced injuries in animal models. Isatin also inhibits monoamine oxidase B (MAO-B) and guanylate cyclase (natriuretic peptide receptors). Schiff base derivatives of isatin inhibit the growth of various cancer cells and tumors, likely due to decreasing cyclin B1 and Cdc2 expression and inducing G2/M phase cell cycle arrest. Derivatives of isatin also inhibit tubulin polymerization, Akt activation, and caspases 3, 7, and 9. Isatin may also exhibit antiepileptic/anticonvulsant activity.