The Extraction of Natural Products using Ultrasound or Microwaves

Abstract

Over the centuries mankind has benefited from the natural materials that occur in plants. In earlier times the whole plant or an extract was used in cooking or as a medicine but nowadays the active constituents of plant extracts provide targets for the synthetic chemist. In this review we will explore the advantages that accrue from the incorporation of either ultrasound or microwaves in the extraction process. The two techniques offer different approaches in that ultrasound is generally used to improve conventional solvent extraction whereas microwaves are known for their ability to remove constituents via heating without solvents. Keywords: Extraction, assisted, ultrasound, microwave, solvent, without solvent, medicinal, nutriceuticals, paclitaxel, tamiflu, flu diseases, shikimic acid, Star Anise, quinine, cinchona tree, Artemisia annua, combat malaria, Aspirin, acetyl salicylate, willow tree bark, anti rheumatic ointments, birch tree bark, biorefinery, ULTRASONICALLY ASSISTED EXTRACTION (UAE), dry biomass, boiling, enfleurage, British Pharma-copoeia, swelling index, extractive value, Improved Diffusion, hydrogen, high-speed, asymmetrical bubble's, Improved Mass Transfer, Acoustic cavitation, Improved Solvent Penetration, Sonocapillary Effect, electrophoresis, Corn cob xylan, corn bran hemicel-luloses, de-polymerization, aqueous ethanol soluble fragments, Lignin, aqueous enzymatic oil extrac-tion, CO2 extraction cell, carnosic acid, Rosmarinus officinalis, Anthraquinones, xyloglucan, ginseng roots, ultrasonic transducers, Sage and valerian extracts, MICROWAVE ASSISTED EXTRACTION (MAE), electromagnetic waves, dielectric loss factor, resonance, microwave extraction reactors, microwave-assisted solvent extraction, compressed, microwave distillation, vacuum microwave hy-drodistillation (VMHD), solvent free microwave extraction, microwave hydro-diffusion and gravity, Soxhlet extraction, essential oil, steam distillation, Microwave Hydrodiffusion, oleifer-ous receptacles, microwave-absorbing extraction solvent, high dielectric constant, low dielectric constant, ergosterol, saponification, supercritical fluid extraction, lycopene