LITMIR.BIZ

Figure 2.8 Right: TLC coupled DPPH autography. Left: TLC plate revealed using UV light (254 nm). Line 1: Rapistrum rugosum extract. Line 2: Sinapis arvensis extract. Mobile phase: toluene-acetone-methylene chloride (40:25:35). Rf: retention factor.

       2.3.2.2 Antiglycant Agents Detection

      The in vitro analysis of antiglycant extracts are based on measuring their inhibitory effect on proteins glycation and related markers in control reactions. The most used models are bovine serum albumin (BSA) and a reducing sugar in a phosphate buffered saline solution (PBS) so the potentially inhibiting extracts are challenged. The systems with and without the extract under analysis are incubated at 37°C or 55°C, or higher temperatures, according to the aim of the study.

      After the isomerization of the Schiff bases, in the advanced phases of the Maillard reaction, very reactive dicarbonyl compounds are formed from proteins residues, called AGEs (advanced glycosilation end products). The main reaction markers for AGEs formation can be crosslinked compounds, fluorescent (such as pentosidine) or nonfluorescent (such as imidazolium dilysine), and not-crosslinked nonfluorescent AGEs, (such as Nε-carboxyethyllysine, CEL and Nε-carboxymethyl-lysine, CML) [142]. Reactive dicarbonyl compounds can also be generated in the lipid oxidation reactions, and some publications stated the correlation between anti-glycant activity and antioxidant activity of natural species [143]. The anti-glycation properties of extracts can be studied by several techniques analyzing different steps of the reaction:

      In the last years several natural aqueous and/or ethanol extracts with antiglycant capacity have been obtained from different natural sources as Allium sativum, Zingiber officinale, Thymus vulgaris, Petroselinum crispum, Murraya koenigii Spreng, Mentha piperita, Curcuma longa, Allium cepa, Piper nigrum [148]. Different polyphenols, mostly phenylpropanoids and flavonoids, which could be present in high concentrations in tea, cinnamon, rosemary, mate and other herbal plants, are efficient trapping agents of a-dicarbonyl compounds, very active glycating agents which are intermediates of the Maillard reaction [146–148].

2.3.3 Biocompounds Conservation and Controlled Delivery Systems

      Most bioactive compounds from natural sources with health benefits are difficult to incorporate in food, cosmetics or pharmaceutical matrices. Some of the reasons include incompatibility with ingredients and low stability under processes and storage conditions (light, oxygen, temperatures, enzymes, acid or alkali mediums, and humidity), which may lead to the loss of their activity and beneficial effects [149].

Several methods have been developed for encapsulation to preserve bioactive compounds at industrial scale. These methods can be classified into three main groups (Figure 2.9): chemical, physicochemical and physical–mechanical. For the selection of the most adequate encapsulation method, it is necessary to consider the production and cost of the process, the desirable morphology and the coating materials [150]. We are presenting an overall view of the recent studies on encapsulation using two of the more simple and widely employed microencapsulation methods, spray drying and coacervation, and protein systems as bioactives delivery and controlled release media.