Phytotoxic bioassays and Fingerprinting by HPLC-DAD of Eragrostis plana Nees Root Extracts - application of chemometrics.

Ana Paula P.K Hendges,Kamyla M Cavalcante,Beatriz Helena L.N.S Maia,Beatriz G.M Moreira,Michelangelo M Trezzi,Sirlei D Teixeira,Vanderlei A De Lima

doi:10.1590/0001-3765202120200129

Abstract

Eragrostis plana (Nees) (Tough Lovegrass) shows ability to interfere with other plants, a phenomenon known as allelopathy. This chemical interaction between plants occurs due to the release of compounds into the environment. Thus, a phytotoxicity study was carried out with E. plana roots collected during each season throughout the year, and the compounds were extracted with solvents of increasing polarity. The data from the bioassays were analyzed by GLM and PCA. In addition, a fingerprint of these extracts was obtained by HPLC-DAD. The extracts in petroleum ether from roots collected in the winter and summer showed greater phytotoxicity on Ipomoea grandifolia germination and growth. The PCA obtained from the chromatogram of the crude extract showed that the extracts in petroleum ether were chemically different from the extracts in ethyl acetate and methanol. Thus, continuing this study in order to develop a new generation of bio-herbicides is essential.

Highlights

Weeds are unwanted plant species that negatively interfere with plants of human interest by reducing agricultural yield, increasing production costs and decreasing product quality, which makes weed control indispensable to farming productivity.The use of synthetic herbicides has been the main tool for weed control worldwide
The aim of this work was to evaluate the seasonal allelopathic potential of the crude extracts of roots from E. plana and to perform a chromatographic fingerprinting by high performance liquid chromatography diode array detector (HPLC-DAD) to evaluate the influence of solvent polarity and seasonality on the extractions, which was aided by principal component analysis (PCA)
Equation 2, generated by the model, predicted that the extracts from the spring and autumn increases the odds of an increase in the radicle length (RL) by 5- and 6-fold, respectively, when compared to extracts from the summer, while extracts from the winter decrease the odds of an increase in the RL by 47% when compared to extracts from the summer

Summary

Introduction

The use of synthetic herbicides has been the main tool for weed control worldwide. The lack of planning for herbicide employment and its indiscriminate utilization has made weed species increasingly resistant to them (Knezevic et al 2016, Maxwell & Mortimer 1994). Herbicide-resistant weeds are currently one of the main problems facing farmers and their presence threatens the food security of the world’s population. There are currently 262 known species (152 dicotyledonous and 110 monocotyledonous) of weeds that are resistant to herbicides. They have developed resistance to 23 of the 26 known mechanisms of action of herbicides, and they are resistance to 167 different herbicides. Herbicide-resistant species have been reported in 93 crops across 70 countries (Heap 2019)

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