Phytochemical screening and toxicity of Crambe abyssinica Hochst extracts on Solanum lycopersicum L., Euphorbia heterophylla L., Bidens pilosa L. and Glycine max (L.) Merril

Ariane Spiassi,Raquel Valmorbida,Luciana Pagliosa Carvalho Guedes,Lorena Camargo De Mendonça,Andréa Maria Teixeira Fortes,Rennan Oliveira Meira,Gislaine Piccolo De Lima

doi:10.14393/bj-v35n5a2019-42328

Abstract

This study aimed to identify the main groups of secondary compounds from Crambe abyssinica and evaluate the bioactivity of the hexane, ethyl acetate and methanol extracts on the seed germination and seedling development of tomato, wild poinsettia, hairy beggartick and soybean. The phytochemical screening considered the presence or absence of total saponins, triterpenoids, flavonoids, coumarins, tannins, phenols and alkaloids. In the seeds it was evaluated: germination percentage, germination velocity index, average germination time, index of allelopathic effects, shoot and root length and seedlings dry matter. In the phytochemical screening it was observed that each solvent extracted different compounds. Flavonoids were found only in the ethyl acetate extract and saponin only in the methanol extract. A high allelopathic effect of hexane, ethyl acetate and methanolic extracts of crambe on the bio-indicator species tomato was observed. The hexane and ethyl acetate extracts also showed inhibitory effect on the weed hairy beggartick and did not present negative effects on soybean. There is the possibility of isolating the bio-active compounds of crambe and use them as a bio-herbicide to the alternative control of the weed hairy beggartick.

Highlights

Plants have the ability to produce chemical substances which can contribute to their survival besides developing defense mechanisms in their environment
Considering the hypothesis that plants extracts used in crop rotation system can inhibit the germination and growth of weeds, due the presence of allelopathic compounds, when evaluated in laboratory conditions, the aim of this study was to identify the main groups of secondary compounds present on crambe (Crambe abyssinica) and evaluate the effect of hexane, ethyl acetate and methanolic extracts on seeds germination and seedlings growth of the bioindicator tomato (Solanum lycopersicum), the weeds wild poinsettia (Euphorbia heterophylla) and hairy beggartick (Bidens pilosa) and the cultivated plant soybean (Glycine max)
The main groups of compounds identified in crambe (C. abyssinica) extracts were: saponins, pentacyclic triterpenoids, free steroids, flavonoids and tannins

Summary

Introduction

Plants have the ability to produce chemical substances which can contribute to their survival besides developing defense mechanisms in their environment. Some allelochemicals are very specific and restricted to certain species or group of related species and, they can be divided into three main groups: terpenes, phenolic compounds and nitrogen compounds (TAIZ; ZEIGER, 2013) These allelopathic substances can cause positive and negative effects on other plants. Such effects include delay or inhibition on seeds germination, paralyzed growth, damages to the root system, chlorosis, withering and plant death (EINHELLIG, 1986; CORREIA et al, 2005; TAIZ; ZEIGER, 2013). These substances are water soluble, highlighting the saponins, tannins, alkaloids, terpenoids and flavonoids, which are released directly into the environment through leaching, root exudates, volatilization and plant residue decomposition (ALVES et al, 2004)

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