Related Experiment Video
Updated: May 21, 2025
Transient Expression in Nicotiana Benthamiana Leaves for Triterpene Production at a Preparative Scale
Published on: August 16, 2018
Recovery techniques for Hydroxynaphthoquinone Enantiomers of Alkanna tinctoria (L.) from Natural Deep Eutectic
Elodie Bossard1, Nikolaos Tsafantakis1, Nektarios Aligiannis1
1Division of Pharmacognosy and Natural Products Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Athens, Greece.
Abstract:
A natural deep eutectic solvent (NaDES) composed of levulinic acid and glucose using a molar ratio of 5 : 1 (molHBA:molHBD) and 20% of water (w/w) (LeG_5_20) was found as a great alternative to the commonly used organic solvents for the extraction of hydroxynaphthoquinone enantiomers (HNQs) from Alkanna tinctoria (L.) Tausch roots. In the present work, a comparative investigation of recovery methods for HNQs, such as solid-phase extraction, macroporous resin, and water as an anti-solvent, was performed to face the main disadvantage of NaDES: the inability to be evaporated. The highest recovery of HNQs was recorded using the solid-phase extraction on a reversed-phase C8 cartridge with a total hydroxynaphthoquinone content (TNC) of 46.79 ± 0.952 mg/g of dry weight (DW). In addition, a great recovery of HNQs was also reported for the macroporous resin Amberlite XAD 4 with a TNC value of 37.21 ± 1.789 mg/g DW, while the precipitation of HNQs by using water as an anti-solvent (1 : 5, v/v) offered a TNC value of 28.68 ± 0.023 mg/g DW. The macroporous resin Amberlite XAD also showed a great potential for larger-scale applications. In fact, the developed scale-up process, involving Amberlite XAD 4, showed a great recovery efficiency for HNQs (34.126 ± 1.093 mg/g DW), an acceptable robustness (RSD < 15%), and the possibility of recycling LeG_5_20 with a recovery greater than 50%; therefore, it is an excellent green alternative extraction procedure for HNQs.
Related Concept Videos
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
02:30Racemic Mixtures and the Resolution of Enantiomers
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
01:38Preparation of Alcohols via Substitution Reactions
Alcohols can be synthesized from alkyl halides via nucleophilic substitution reactions. The highly polar carbon-halogen bond in the substrate makes halide a good leaving group.ÃÂ The hydroxide ion or water can act as a nucleophile to take the place of halide and form an alcohol. The substitution reactions occur via two different reaction pathways, SN1 or SN2,ÃÂ depending on the nature of carbon attached to the halide.
Primary alcohols are synthesized from primary alkyl...
02:29Ethers from Alcohols: Alcohol Dehydration and Williamson Ether Synthesis
Ethers can be prepared from organic compounds by various methods. Some of them are discussed below,
Preparation of Ethers by Alcohol Dehydration
In this method, in the presence of protic acids, alcohol dehydrates to produce alkenes and ethers under different conditions. For example, in the presence of sulphuric acid, dehydration of ethanol at 413 K yields ethoxyethane, whereas it yields ethene at 443 K.
02:35Acid-Catalyzed Dehydration of Alcohols to Alkenes