Abstract Detail

Physiology

Qureshi, Dr. Huma [1], Anwar, Dr. Tauseef [1], Adkins, Steve William [2].

Isolation of vitexin as natural bio-herbicide from Lantana camara leaves.

‘Yield maximization’ is the last word of modern agriculture for food security of ever increasing population of the world. Maximizing world’s agricultural efficiency depends largely on controlling a variety of pests and diseases. Among pests, weeds have largest negative impact on crop productivity. Among main strategies used to control weeds (i.e., physical, mechanical, chemical and biological) the chemical method is most popular for decreasing negative effects of weeds in crops. But, herbicide-resistant weeds have been emerging due to extensive use of synthetic chemical herbicides, and public concerns over impact of synthetic herbicidal chemicals on environment and human health are increasing. Natural compounds, known as “bio-herbicides” pose a big area for environmentally safe herbicides, based on compounds produced by living organisms. In current study, crude methanol extract of invasive toxic plant Lantana camara leaves was prepared by cold maceration technique and was subjected to fractionation. Fractionation resulted in three organic (ethyl acetate, chloroform and n-hexane) and one aqueous fraction for the crude extract. Bioassays were performed at 10,000ppm, 1,000 ppm and 500ppm concentration against selected weed test species (monocot: Avena fatua and Phalaris minor; Dicot: Rumex dentatus and Chenopodium album). Chloroform fraction was selected on the basis for its highest herbicidal activity. Silica gel was used for column chromatography. Sample was loaded after adsorption on silica gel by making a uniform and even layer. Mobile phase of Hexane: Ethyl acetate (60:40) was used based on TLC profiling. A total of 31 elusions were collected in small column vials. They were left overnight to make them concentrated and were again subjected to Thin Layer Chromatography (TLC). Vanillin TLC stains was used for visualization purpose. Fractions with similar TLC pattern were combined and bio-assayed against radish seeds at 1mg/mL. Sub-fraction (iii) of fraction 23 showed highest growth inhibition therefore selected for further analysis. GC-MS (Shimadzu GC-MS-QP2010 ultra) with Helium gas as carrier was used to find out purity of compound and possible compound identification. GCMS analysis showed the compound as Vitexin (C₂₁H₂₀O₁₀) (flavone glucoside). To the best of our knowledge Lantana camara leaves have not been previously reported to possess flavonoid compound ‘vitexin’ and tested against weeds of wheat crop.

1 - Pir Mehr Ali Shah Arid Agriculture University, Shamsabad, Murree Road, Rawalpindi, Punjab, 46300, Pakistan
2 - The University of Queensland, School of Agriculture and Food Science, St. Lucia, 4072, Australia

Keywords:
Vitexin
Weed control
Natural herbicides
Allelopathy.

Presentation Type: Oral Paper
Session: PHYS1, Physiology
Location: San Pedro 2/Starr Pass
Date: Monday, July 29th, 2019
Time: 8:30 AM
Number: PHYS1003
Abstract ID:133
Candidate for Awards:None