Optimization of the formation of vinyldithiins, therapeutic compounds from garlic

in European Food Research & Technology (2013)

Allyl sulfides, ajoenes and vinyldithiins are the three main groups of volatile organosulfur compounds that are formed when garlic is crushed. The manner garlic is processed (nature of the extraction ... [more ▼]

Allyl sulfides, ajoenes and vinyldithiins are the three main groups of volatile organosulfur compounds that are formed when garlic is crushed. The manner garlic is processed (nature of the extraction medium, temperature…) has a major influence on their relative proportion and the amounts produced. It has been proven recently that the vinyldithiins are at the origin of garlic’s capacity to prevent adipocytes development. Their incorporation in garlic-based nutraceuticals is thus particularly interesting. In this context, this work aims to optimize the production of vinyldithiins from garlic. After having determined the best garlic origin (Spanish) and the best oil for the extraction (olive or sunflower oil), the extraction conditions were optimized (1/2 (w/w garlic oil), 37 °C, 6 h) and 133 mg of vinyldithiins was obtained from 100 g of fresh garlic. Carrying out the extraction under microwave irradiation allowed increasing the yield 3.6-fold (yield 486 mg of vinyldithiins from 100 g of fresh garlic). This study may also contribute to the development of new garlic derived high value products by enhancing the comprehension of their formation. [less ▲]

Enzymatic synthesis and surface properties of novel rhamnolipids

in Process Biochemistry (2013), 48

New rhamnolipids were obtained via the development of a synthesis procedure consisting of two biocatalyzed steps. In the first step, naringinase was used to introduce a primary alcohol function onto ... [more ▼]

New rhamnolipids were obtained via the development of a synthesis procedure consisting of two biocatalyzed steps. In the first step, naringinase was used to introduce a primary alcohol function onto rhamnose by glycosylation of 1,3-propanediol. In the second step, immobilized lipase B from Candida antarctica catalyzed the esterification of the primary hydroxyl group with mono- and di-carboxylic fatty acids of increasing chain length (from C8 to C14). For the monoic acids, the initial rate and 24 h yield decreased with increasing chain length. For the dioic acid, the number of carbon atoms of the acid did not influence these parameters. The new rhamnolipid obtained with tetradecanoic acid showed very good surface properties. At pH 5, it had a very low critical aggregation concentration of 1.70 M and it diminished water’s surface tension to 27.6 mN/m. It was also able to form stable insoluble monolayers. On the other hand, the rhamnolipid formed with tetradecanedioic acid showed far less interesting surface properties. [less ▲]

(Bio)synthesis, extraction and purification of garlic derivatives showing therapeutic properties

in Smagghe, Guy; Boeckx, Pascal; Bossier, Peter (Eds.) et al Communications in Agricultural and Applied Biosciences 2013 (2013)

Garlic has been used worldwide for centuries for its taste but also for its health benefits. Garlic's therapeutic compounds are mostly organosulfur compounds, recognized for their antioxidant, anticancer ... [more ▼]

Garlic has been used worldwide for centuries for its taste but also for its health benefits. Garlic's therapeutic compounds are mostly organosulfur compounds, recognized for their antioxidant, anticancer, anti-inflammatory and antimicrobial activity and their effect on cardiovascular diseases (reviewed by Block, 2010). When the cloves are crushed, allicin is synthesized as the vacuolar enzyme alliinase meets its substrate, the cytoplasmic alliin. Allicin is unstable and undergoes rearrangements to form three main groups of derivatives: allyl sulfides, ajoenes and vinyldithiins. The garlic processing method has a major influence on the products released both in terms of chemical composition and yields. For example, the type of medium (aqueous or oily) and the temperature can favour the formation of specific compounds. Our work aims at studying the influence of - the garlic origin, - the reaction conditions and - the extraction procedures (solvent, microwaves) on the organosulfur compounds formed. Particular attention is given to the stereochemistry and the stability of the compounds. Better understanding of the formation of high value natural molecules is important in order to lead further studies on the biological activity of the compounds or to use them as nutraceuticals. [less ▲]

Analysis of the diastereoisomers of alliin by HPLC

in Talanta (2012), 101

Garlic has been known for its therapeutic effects for centuries and is used worldwide as a functional food. The concentration of the active molecules could be enhanced by a better knowledge of their ... [more ▼]

Garlic has been known for its therapeutic effects for centuries and is used worldwide as a functional food. The concentration of the active molecules could be enhanced by a better knowledge of their biosynthesis. The precursor of these compounds, alliin (a sulfur amino-acid) has been obtained by chemical synthesis. However, this synthesis route also leads to a diastereoisomer as co-product. This work describes the development of an analytical method which allows the separation and quantification of the two diastereoisomers in order to determine in which proportion the natural form can be produced. The HPLC method which was optimized and validated by accuracy profile exploits an original stationary phase consisting of porous graphitic carbon (PGC). Furthermore, the developped method was used to separate the diastereoisomers of methiin, another garlic cysteine sulfoxide, and to analyse and aqueous extract of garlic. The ability to quantify the amount of natural alliin is valuable for further work on garlic molecules and their application for health protection. [less ▲]

Use of ionic liquids for biocatalytic synthesis of sugar derivatives

in Journal of Chemical Technology & Biotechnology (2012), 87(4), 451-471

Sugar-based compounds are widely used in pharmaceuticals, cosmetics, detergents and food. They are mainly produced by chemical methods, but the use of enzymes as ‘a greener alternative’ to organic ... [more ▼]

Sugar-based compounds are widely used in pharmaceuticals, cosmetics, detergents and food. They are mainly produced by chemical methods, but the use of enzymes as ‘a greener alternative’ to organic synthesis has been investigated for more than 20 years. Due to the low polar substrate solubility in organic solvents compatible with enzymes, research has focused on the application of substitutes for biocatalysis, especially ionic liquids (ILs). After introducing the main properties of ILs and especially their ability to solubilize sugars, this review focuses on one of their applications, the biocatalytic synthesis of carbohydrate derivatives. In this context, they can be used in pure IL systems, in IL/IL systems or in IL/organic solvent systems. Finally, this review provides an update on the environmental fate of ILs. Their exploitation in ‘green’ processes is still limited due to their low degradability but research is currently under way to design new more ‘eco-friendly’ ILs. [less ▲]

Structure, properties and obtention routes of flaxseed lignan secoisolariciresinol

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(1), 115-124

Following a brief description of the structure and nomenclature of the lignan family, this review focuses on the flaxseed lignan secoisolariciresinol (SECO). The main properties, the analysis methods and ... [more ▼]

Following a brief description of the structure and nomenclature of the lignan family, this review focuses on the flaxseed lignan secoisolariciresinol (SECO). The main properties, the analysis methods and two routes for the preparation of SECO, i.e. extraction from renewable raw material and (hemi)-synthesis, are reviewed. Green methods recently developed for the first route and chemical syntheses inspired from biosyntheses for the second one are the main subjects of this paper. [less ▲]

d-Xylose-based bolaamphiphiles: Synthesis and influence of the spacer nature on their interfacial and membrane properties

in Comptes Rendus Chimie (2012), 15

Synthesis of novel carbohydrate surfactants by combination of enzymatic catalysis and thiol-Michael addition

Poster (2011, April 29)

Synthesis and physico-chemical characterization of bolaamphiphiles derived from alkenyl D-xylosides

in New Journal of Chemistry (2011), 35

Influence of co-solvents and molecular sieve on mannose enzymatic acylation.

Poster (2010, October 14)