Cyanogenic constituents in woody plants in natural lowland rain forest in Costa Rica

Screening of fresh leaves and other plant organs revealed the presence of cyanogenesis in 25 species in 16 families out of a total of 188 species in 79 families vouchered in natural lowland rain forest in Costa Rica. In a qualitative screening of a random sample based on seven one-hectare inventories of woody plants, we found cyanogenesis in 4.0% of all species; these represented 2.5% of all individuals present, and 3.0% of the total basal area of stems. The frequency of occurrence of cyanogenic compounds was higher in reproductive plant parts than in leaves, and highest in pericarps. Cyanogenesis was found in Annona amazonica, Annona pittieri, Cymbopetalum costaricense, Tabebuia chrysantha, Sloanea tuerckheimii, Sapium laurifolium, Lecointea amazonica, Carpolroche playptera, Mayana odorata, Byrsonima crispa, Miconia splendens, Inga acuminata, Chaunochiton kappleri, Passiflora ambigua, P. pittieri, P. talamancensis, P. vitifolia, Panopsis costaricensis, Faramea parvibractea, Paullinia capreolata, Pouteria amygdalicarpa, P. campechiana, P. subrotata, P. torta and Rinorea guatemalensis. Some taxonomic implications are discussed. The identity of cyanogenic constituents found in dried material of these species is presented, as is the total cyanogenic potential (CNp) of 11 positive species. The CNp ranged from less than 5 to approx. 2000 mg kg(-1) f.w. Several species were cyanogenic only in some individuals. A total of 463 species gave no positive test for cyanogenic glycosides. Tests on leaves and seeds of Ampelocera macrocarpa indicated the content of a rare and unknown volatile constituent. (C) 1997 The Linnean Society of London.