Characterization and Deer-Repellent Property of Chrysophanol and Emodin from Sicklepod Weed

摘要

Deer, particularly white-tailed deer (Odocoileus virginianus), damage row crops such as soybean (Glycine max L.) and are a perceived problem in the continental US. Currently, the only widely used technique to control deer from crop browsing is establishment of fences, which is expensive, labor intensive, and most of the time ineffective. Studies have shown that sicklepod, Senna obtusifolia (L.), contains anthraquinone derivatives, which in separate studies were shown to be toxic to cattle, rats, rabbits, and horses, and repel herbivores primarily birds. However, information of the deer-repelling property of anthraquinone in sicklepod is lacking. Field tests conducted at our Captive Deer Facility at MississippiStateUniversity(MSU) confirmed the deer-repelling property of anthraquinone extracts from sicklepod. Soybean plants applied with control treatment (water) were browsed by deer, while plants applied with sicklepod anthraquinone extracts were avoided. Using chromatography techniques, we found the levels of anthraquinone derivatives (chrysophanol, emodin) in sicklepod plant parts in the order: root > fruit > stem/leaf. Hydrolysis of water extracts of sicklepod seed produced high emodin concentration, suggesting emodin glycoside as the main form of anthraquinone glycoside in sicklepod seed. Deer-repelling compounds can be extracted in its pure form from sicklepod and applied on soybean to increase its repelling efficacy on deer, and at the same time protect soybean yields.