Ent-kaurane diterpenoid herbicides from natural sources for sustainable weed control

Overview

This research proposes the development of ent-kaurane diterpenoid derivatives as next-generation, environmentally friendly herbicides for major agricultural crops. The active compounds are derived from atractyligenine, obtained through extraction and hydrolysis of glucoside atracyloside (ATR) from the rhizome of the Atractylis gummifera thistle. Preliminary testing has demonstrated that chemically modified analogues can inhibit the growth of both roots and shoots of test plant species at low micromolar concentrations, indicating strong phytotoxic potential. These herbicides are designed to be tailored for selective weed control and are not expected to display cross-resistance with existing commercial herbicide products, addressing a growing challenge in modern agriculture.

Technical specifications

Source and production:

• Ent-kaurane scaffold extracted from A. gummifera rhizome at approximately 1% yield (450 g of rhizome yields 4.1 g of ATR)
• Hydrolysis of ATR produces atractyligenine in quantitative yield
• Chemical modification of the genine generates a library of analogues with herbicidal activity

Key active compound:

• ((2R,4R,4aR,6aR,7S,9R,11aS,11bR)-2,7-dihydroxy-11b-methyl-8-methylenetetradecahydro-6a,9-methanocyclohepta[a]naphthalen-4-yl)(piperidin-4-yl)methanone demonstrated inhibition of radicle and shoot growth in L. sativa at 10 µmol/L

Testing methodology:

• Phytotoxic activity assessed against Lolium perenne and Lactuca sativa at concentrations ranging from 1 mmol/L to 10 nmol/L
• Tetracyclic diterpenoids evaluated for their role in plant-plant and plant-pathogen interactions

Target applications:

• Weed control in rice, wheat, corn, cotton, soybean, peanut, and potato cultivation
• Potential activity against resistant grass species including Echinochloa, Leptochloa chinensis, Aegilops tauschii, and Alopecurus japonicus

Technology readiness level

The technology is currently at an early-to-mid stage of development. Proof-of-concept has been established through extraction, purification, chemical modification, and initial bioactivity screening of ent-kaurane derivatives against model plant species. Future validation efforts will focus on three key areas: synthesising additional derivatives to expand the compound library, optimising greenhouse culture conditions for A. gummifera to ensure sustainable sourcing, and elucidating the mode of action through assays such as the COMET assay for DNA damage evaluation. Partnership opportunities exist to test new kaurenoids against resistant grass species and determine selectivity profiles in relation to specific crops of interest.