Metabolites from Withania aristata with potential phytotoxic activity

Area of Science:

• Natural Product Chemistry
• Phytochemistry
• Plant Physiology

Background:

• Withania aristata is a plant source of bioactive compounds.
• Apocarotenoids and carotenoids are classes of plant metabolites with diverse biological activities.
• Phytotoxicity assays are crucial for understanding plant growth regulation.

Purpose of the Study:

• To isolate and characterize apocarotenoids and carotenoids from Withania aristata leaves.
• To evaluate the phytotoxicity of these isolated compounds.
• To identify potent phytotoxic agents for potential applications.

Main Methods:

• Isolation of metabolites using chromatographic techniques.
• Structure elucidation via Nuclear Magnetic Resonance (NMR) and Electrospray Ionization Mass Spectrometry (ESI-MS).
• Phytotoxicity assessment using etiolated wheat coleoptile bioassay and assays on Lepidium sativum, Lactuca sativa, Lycopersicum esculentum, and Allium cepa.

Main Results:

• Several apocarotenoids (1-8) and one carotenoid (9) were isolated.
• A novel tetraacetylated apocarotenoid glucoside derivative (10) was synthesized and characterized.
• Lutein (9) exhibited the most significant phytotoxicity, followed by vomifoliol (1) and 9-hydroxymegastigma-4,6E-dien-3-one (2).

Conclusions:

• Withania aristata is a rich source of apocarotenoids and carotenoids.
• Lutein and specific apocarotenoids possess notable phytotoxic properties.
• These findings contribute to understanding the phytochemistry and bioactivity of Withania aristata.