Germination and Growth of the Invasive Weeds Bidens pilosa and Digitaria insularis Regulated by Novel Kaurane Diterpene Amides
Rondinelle Gomes Pereira
Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil
Maria Amélia Diamantino Boaventura *
Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil
Queila Souza Garcia
Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, 31270-901, Belo Horizonte, MG, Brazil
Bárbara Castro Vieira
Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, 31270-901, Belo Horizonte, MG, Brazil.
*Author to whom correspondence should be addressed.
Abstract
Novel kaurane ditepene monoamides were synthesized with good yields, directly from unprotected symmetrical aliphatic and aromatic diamines, hydroxylamines, dichlorophenylamines and ent-kaurenoic acid (1), using a modified protocol for monoacylation. These amides were tested against seed germination and growth of radicle and shoot of the weeds Bidens pilosa (Asteraceae), and Digitaria insularis (Poaceae). The concentrations used were 1.0 mM, 100.0, 10.0, and 1.0 mM. Propanil, the commercial herbicide, was used as internal reference. Monoamides from symmetrical aliphatic diamines were the most actives. Their log P (3.66-4.20) were closer to the value of 4.15, appropriate for herbicides. They were, in some cases, at the lower concentrations, more active than propanil. Generally, inhibitory effects were more significant on B. pilosa than on D. insularis.
Monomide from ethylenediamine gave the best dose / response for inhibition growth of radicle and shoot of B. pilosa, with I50 3.25 and 16.3 mM, respectively.
Keywords: Kaurane diterpenes amides, phytotoxicity, Bidens pilosa, Digitaria insularis