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

Abstract

RESUMO -Este estudo visou identificar substâncias biologicamente ativas e o potencial alelopático de esteroides glicosilados, provenientes das sementes de Annona crassiflora. O isolamento dos esteroides glicosilados foi realizado com a separação dos constituintes químicos do extrato bruto de acetato de etila em coluna cromatográfica, sendo a completa elucidação estrutural por meio de espectroscopia de RMN 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 25 o C 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 25 o C 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.

Effect of Serjania lethalis ethanolic extract on weed control

“…These results are in agreement with the finding that extracts of allelopathic plants generally have more pronounced effects on radicle rather than hypocotyl growth (Inoue et al, 2010;Grisi et al, 2012). Root growth is characterized by high metabolic rates, and for this reason roots are highly susceptible to environmental stresses, such as allelochemicals in substrate (Cruz-Ortega et al, 1998).…”

“…The effects of hydroalcoholic extracts of Annona crassiflora leaves and stems on the germinability and mean germination rate of wild poinsettia seeds were similar, but the stem extracts more strongly inhibited shoot and root growth than did the leaf extracts (Inoue et al, 2010). Li & Jin (2010) also reported that the stem extracts of Mikania micrantha showed higher inhibitory activity than the leaf extracts.…”

“…The experiment was conducted in a germination chamber at 25 o C, with a photoperiod of 12 hours (Inoue et al, 2010). The germination criterion was based on embryo protrusion, which was evaluated every 12 hours during the first seven days of the experiment and at intervals of 24 hours thereafter until the stabilization of germination.…”

Phytotoxic activity of crude aqueous extracts and fractions of young leaves of Sapindus saponaria L. (Sapindaceae)

“…. Th e root system was more sensitive to allelochemicals than shoot seedling Root sensitivity to allelochemicals is well documented in the literature, as it is one of the characteristics that best indicates the phytotoxicity of plant extracts (Inoue et al 2010;Souza et al 2010;Grisi et al 2012). Th is can be attributed to the fact that root growth is characterized by high metabolic rates and the roots are therefore highly susceptible to environmental stress, such as allelochemicals in the substrate (Cruz-Ortega et al 1 998).…”

Atividades biológicas dos alcaloides de Annona crassiflora Mart.

“…Vários aleloquímicos foram descritos de diferentes espécies de plantas, sendo alguns exemplos os benzoxazinoides, as benzoquinonas, os glucosinolatos e os terpenos (Jabran, 2017 (Inoue et al, 2010b).…”