NADES-based essential oil extraction and isolation of new epoxysesquiterpene from Ageratina adenophora flowers
Gaurav Aggarwal, Prithvi Pal Singh, Manish Gupta, Upendra Sharma
Abstract
During the past decade, natural deep eutectic solvents (NADESs) have emerged as a green alternative to conventional organic solvents due to properties like low toxicity, diverse metabolite solubility, and biodegradability. In the present study, choline chloride (CC) and lactic acid (LA)-based NADES has been utilized as pre-extraction media prior to the hydrodistillation of Ageratina adenophora flowers. CC and LA were used in three different molar ratios (1:1, 1:2 and 1:3) along with water to extract essential oil from flowers. The essential oil yield was found to be increased from 2.84 mg/g to 13.52 mg/g using NADES-assisted hydrodistillation. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) were used to analyse the chemical diversity of the essential oils. In addition, a new epoxy containing sesquiterpene molecule named 5,11-epoxycadin-3,4-en-8-one, was also isolated from the essential oil without chromatography techniques. The molecular structure and absolute configuration have been deduced using NMR spectroscopy (1D & 2D NMR), and single-crystal X-ray diffraction (SC-XRD), respectively. Also, the morphology of the crystal surface was studied using scanning electron microscopy (SEM). Furthermore, the anti-acetylcholinesterase activity of the essential oils and isolated new molecule has also been investigated.