Allelochemical potential of Metopium brownei

Metopium brownei is a tree that grows in coastal tropical forests along the Gulf of Mexico and in the Yucatan Peninsula. This medicinal species produces a strongly irritant exudate, and sometimes forms pure populations favored by fire. The bioactivity of the aqueous leachates, organic extracts (leaves, bark, and wood), and mixtures of urushiols and flavonoids from M. brownei were evaluated on the growth of two plants: Amaranthus hypochondriacus and Echinochloa crusgalli, and four phytopathogenic fungi: Fusarium oxysporum, Helminthosporium sp., Alternaria sp., and Pythium sp. Alkylcatechols (urushiols) were isolated from an acetone extract of the bark. Dihydroquercetin and eriodictyol were isolated from the chloroform-methanol extract of the wood. In addition, masticadienoic acid was isolated from the leaves. The aqueous leachates, organic extracts, and the mixtures of flavonoids and urushiols were inhibitory to the growth of test plants and phytopathogenic fungi. The allelochemical role of the bioactive compounds from M. brownei is discussed in relation with other results reported in some studies on Anacardiaceae family and M. brownei.