From the flowers of Couroupita guianensis, an aliphatic hydrocarbon and stigmasterol have been isolated.
Abstract of new scientific research: The antimicrobial activity of extracts from Couroupita guianensis Aubl. tissues were measured against 12 gram positive, 12 gram negative, and one protozoan. Methanol extracts of leaves, flowers, fruit, stem and root barks, and stem and root heartwood of the plant inhibited growth of the microorganisms, a phenomena that was enhanced by further fractionation of the methanol extracts into petrol, dichloromethane, ethyl acetate and butanol soluble fractions. Most activity was in the petrol fractions of the flowers, fruit, and stem bark; the ethyl acetate fraction of the flowers, and stem and root bark; and the dichloromethane fractions of the stem and root barks. Some fractions of the stem bark and flowers exhibited antifungal activity.
(M. R. Khan, M. Kihara, A. D. Omoloso. 2003. Antibiotic Activity of Couroupita guianensis. Journal of Herbs, Spices and Medicinal Plants. Volume: 10 Issue: 3. p:95-108.)