Avaliação do potencial alelopático de substâncias isoladas em sementes de araticum (Annona crassiflora)

Abstract

This work aimed to identify substances and the allelopathic potential of steroidal glycosides, isolated from the seeds of Annona crassiflora. Isolation of steroidal glycosides was carried out with the separation of chemical components of ethyl acetate extract in a chromatographic column and identified by 1H NMR. Germination tests with Euphorbia heterophylla and Ipomoea grandifolia were carried out in BOD Germinator at 25ºC and 12 hr photoperiod, monitored for 10 days at concentrations of 0, 20, 40, 80 and 100 mg L-1 of the materials isolated. Using the same concentrations, experimental radicle and hypocotyl development was maintained at 25ºC with 24hr photoperiod for 10 days. After the ethyl acetate extract was submitted to fractioning, the presence of characteristic signs of steroids in the 1H NMR spectrum was verified, providing a mixture of stigmasterol and sitosterol glycoside. The results indicate that the substances stigmasterol and sitosterol did not inhibit germination and germination velocity index (SIG) of E. heterophylla and I. grandifolia. However, both substances affected radicle and hypocotyl development of E. heterophylla.