A phytochemical study of Borneo : Sarawak Lowland forests

Plants (79 species) from the lowland forests of Sarawak were screened for phytochemicals (alkaloids, saponins, terpenes and flavonoids) and selected bioactivities. Alkaloid yielding plants were mainly from Annonaceae (20%), Apocynaceae (20%) and Rubiaceae (10%) families. Of the plants collected, 10 expressed larvicidal activity and 17 species provided hypotensive alkaloids. New bioactive styrylpyrone derivatives, (+)5b-hydroxygoniothalamin and (- ) iso-5-deoxygoniopypyrone, isolated from Goniothalamus dolichocarpus exhibited significant toxicity to the Aedes aegypti larvae.