title: Extraction mechanism of ultrasound assisted extraction and its effect on higher yielding and purity of artemisinin crystals from Artemisia annua L. leaves.
abstract: This study proposes an ultrasound-horn system for the extraction of a natural active compound "artemisinin" from Artemisia annua L. leaves as an alternative to hot maceration technique. Ultrasound leaching improves artemisinin recovery at all temperatures where only ten minutes is required to recover 70% (4.42mgg-1) compared to 60min of conventional hot leaching for the same yield. For instance, ultrasound treatment at 30°C produced a higher yield than the one obtained by conventional maceration at 40°C. Kinetic study suggests that the extraction pattern can be assimilated, during the first ten minutes, to a first order steady state, from which activation energy calculations revealed that each gram of artemisinin required 7.38kJ in ultrasound versus 10.3kJ in the conventional system. Modeling results indicate the presence of two extraction stages, a faster stage with a diffusion coefficient of 19×10-5cm2min-1for ultrasound technique at 40°C, seven times higher than the conventional one; and a second deceleration stage similar for both techniques with diffusion coefficient ranging from 1.7 to 3.1×10-5cm2min-1. It is noted that the efficient ultrasound extraction potential implies extraction of higher amount of co-metabolites so low artemisinin crystal purity is engendered but a combination with a purification step using activated charcoal and celite adsorbents produced crystals with comparable purity for conventional and ultrasound samples.
authors: Extraction & Separation Techniques Team, Centre de Recherches Scientifique et Technique en Analyses Physico-Chimiques (C.R.A.P.C.), BP 248 Alger RP 16004, Algiers, Algeria. Electronic address: chemats@yahoo.fr.
authors: Smain
authors: S
authors: Chemat
authors: Extraction & Separation Techniques Team, Centre de Recherches Scientifique et Technique en Analyses Physico-Chimiques (C.R.A.P.C.), BP 248 Alger RP 16004, Algiers, Algeria.
authors: Abdallah
authors: A
authors: Aissa
authors: Extraction & Separation Techniques Team, Centre de Recherches Scientifique et Technique en Analyses Physico-Chimiques (C.R.A.P.C.), BP 248 Alger RP 16004, Algiers, Algeria; Faculté de Chimie, Université Houari Boumediene (USTHB), BP 32, El-Alia 16112 Bab-Ezzouar, Alger, Algeria.
authors: Abdenour
authors: A
authors: Boumechhour
authors: Faculté de Chimie, Université Houari Boumediene (USTHB), BP 32, El-Alia 16112 Bab-Ezzouar, Alger, Algeria.
authors: Omar
authors: O
authors: Arous
authors: Faculté de Génie des Procédés et de Génie Mécanique, Université Houari Boumediene (USTHB), BP 32, El-Alia 16112 Bab-Ezzouar, Alger, Algeria.
authors: Hamid
authors: H
authors: Ait-Amar
mesh_terms: D000327:Adsorption; D031172:Artemisia annua / Q000737:chemistry*; D037621:Artemisinins / Q000737:chemistry / Q000302:isolation & purification*; D005591:Chemical Fractionation / Q000379:methods*; D018515:Plant Leaves / Q000737:chemistry*; D013696:Temperature; D000069453:Ultrasonic Waves
chemical_list: D037621:Artemisinins; C031327:artemisinin
keywords: Artemisinin; Crystallisation; Diffusion coefficient; Extraction; Purification; Ultrasound