Jorge E. Wong-Paz

Ultrasound-assisted extraction of phenolic compounds from Laurus nobilis L. and their antioxidant activity.

Bay leaves (BL) (Laurus nobilis L., Family: Laureceae) are traditionally used to treat some symptoms of gastrointestinal problems, such as epigastric bloating, impaired digestion, eructing and flatulence. These biological properties are mainly attributed to its phenolic compounds. In this paper, ultrasound-assisted extraction of phenolic compounds from Laurus nobilis L. (Laureceae) was studied. Effects of several experimental factors, such as sonication time, solid/liquid ratio and concentration of solvent on extraction of phenolic compounds were evaluated through a randomized complete block design with factorial treatment arrangement (3(3)). The best extraction conditions were: 1g plant sample with 12 mL of 35% ethanol, for 40 min, obtaining a yield of phenolic compounds of 17.32±1.52 mg g(-1) of plant. In addition, free radical-scavenging potential of DPPH and lipid oxidation inhibition, by linoleic acid peroxidation of the selected extract was measured in order to evidence their antioxidant properties. Results indicated that high amounts of phenolic compounds can be extracted from L. nobilis by ultrasound-assisted extraction technology.

Total phenolic content, in vitro antioxidant activity and chemical composition of plant extracts from semiarid Mexican region

OBJECTIVE To determine the extraction suitable conditions of total phenolic content (TPC) by heat-reflux system, antioxidant activities and HPLC characterization of the aqueous-ethanolic extracts of Jatropha dioica (J. dioica) (Dragons blood), Flourensia cernua (F. cernua) (Tar bush), Eucalyptus camaldulensis (E. camaldulensis) (Eucalyptus) and Turnera diffusa (T. diffusa) (Damiana). METHODS TPC was evaluated by the well-known colorimetric assay using Folin-Ciocalteu reagent. The antioxidant activities were assayed by three methods based on scavenging of DPPH, ABTS and by lipid oxidation inhibition. The chemical composition of the extracts obtained was subject to HPLC analysis. RESULTS TPC in the plant extracts ranged from 2.3 to 14.12 mg gallic acid equivalents/g for J. dioica and E. camaldulensis, respectively. The plant extracts of F. cernua, E. camaldulensis and T. diffusa showed similar strong antioxidant activities on scavenging of DPPH and lipid oxidation inhibition. In contrast, J. dioica extracts had lowest potential antioxidant in three assays used. HPLC assay showed the presence of several phenolic compounds in the extracts used. CONCLUSIONS The results obtained suggest that F. cernua, E. camaldulensis and T. diffusa are potential sources to obtain bioactive phenolic compounds with high antioxidant properties which can be used in the factories as antioxidant agents or for treatments in diseases.

Influence of thermal effect on sugars composition of Mexican Agave syrup

Agave syrup is a fermentable by-product from the Agave industry that is used for pulque production, a typical Mexican fermented beverage. However, to date, the information available on its physicochemical composition is scarce, with this study being one of the first contributions on the subject. Here the influence of thermal treatment at 121ºC/15 min on the physicochemical composition of agave syrup was studied. The chemical composition based on sugar content was evaluated by thin-layer chromatography and high-performance liquid chromatography. In addition, the mass spectrum is also presented. Results showed that thermal treatment promoted a change in the chemical composition of the agave syrup, particularly in sugar concentration favoring a high sucrose concentration after the sterilization process. Fructose, glucose in particular, and kestose (GF2) were detected in both samples. The presence of prebiotics such as GF2 suggests that agave syrup may be used in food and nutraceutical industries as a functional beverage.

Microplate Quantification of Total Phenolic Content from Plant Extracts Obtained by Conventional and Ultrasound Methods

INTRODUCTION There is increasing interest in phenolic compounds around the world because of their potential positive impact on human health. Phenolic compounds are largely found in fruits and vegetables. Extraction of phenolic compounds is a very important step in their recovery. The newly developed technique of ultrasound-assisted extraction (UAE) appears to be an advantageous alternative compared with conventional techniques, because it is simple and environmental friendly. The potential of UAE needs to be evaluated in each plant in order to demonstrate its efficiency. OBJECTIVE The objective of the present study was to compare a conventional method and UAE on the extraction efficiency of phenolic compounds from Jatropha dioica, Fluorensia cernua, Turnera diffusa and Eucalyptus camaldulensis plants and evaluate the in vitro anti-oxidant potential. METHODS Validation of the new method was carried out using mixed-model methodology and regression analysis. Feasibility of this new method was shown and applied using several plants extracts obtained by different extraction methods from semi-arid Mexican plants, which were characterised by high levels of polyphenols. Additionally, the anti-oxidant potential of these extracts was determined by 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. RESULTS Results showed that the new microplate method can be used to determine total phenolic content in plant extracts. Additionally, an alternative extraction method by ultrasound was less efficient compared with the conventional method. CONCLUSION The tested plants are good candidates to obtain nutraceuticals and functional food ingredients.

Ellagitannins: Bioavailability, Purification and Biotechnological Degradation

The ellagitannins are a group of phenolic compounds with biological activities. Ellagic acid is the product obtained from hydrolysis of ellagitannins. Information related to the biosynthesis of ellagitannins still been scarce and confused. The ellagitannins are obtained from plants and their purification process implies mainly the use of chromatographic techniques. The ellagitannin acyl hydrolase (EAH) also known as ellagitannase is an enzyme capable of hydrolyzing the ester bonds of ellagitannins and the consequent releasing of ellagic acid. Information about the EAH is not clear because the enzyme had showed different activities due to the low purity or complexity of substrates and there is no available information about the biochemical, physicochemical and molecular characteristics of EAH. The present review describes information related to the sources, biosynthesis and the purification of ellagitannins and a current assessment on the production of ellagitannase.

Bioactive compounds from bay leaves (Laurus nobilis) extracted by microwave technology

Abstract Laurus nobilis leaves contain flavored and bioactive components with relevant biological properties for human health that are attributed to an abundant presence of highly bioactive secondary metabolites. However, the separation process for these bioactive molecules from plant matrix is seriously limited by the presence of a physical barrier (cell wall). Thus, the use of novel extraction procedures to enhance their release is particularly important. In this work, the potential use of microwave-assisted extraction (MAE) as a tool to improve the extraction efficiency of bioactive compounds from bay leaves and their characterization was evaluated. The effects of irradiation time (3, 6 and 9 min) and aqueous ethanol concentration (0, 25 and 50%) on the extraction of phenolic compounds were evaluated. A response surface methodology was applied to determine the best extraction conditions by MAE. The maximum total phenolic compound under the best conditions (9 min time irradiation and aqueous ethanol 50%) was 10.63±0.91 mg gallic acid equivalent/g plant using MAE. Also, the antioxidant potential of the extracts obtained was evaluated.

Utilization of Citrus Waste Biomass for Antioxidant Production by Solid-State Fermentation

Citrus fruits such as lemon, orange, grapefruit, and tangerine are consumed for their flavor, low cost, and human health benefits. However, citrus juice extraction generates by-products that are mostly unused and is discharged in landfills. In this study, the by-products of lemon, orange, grapefruit, and tangerine were subjected to solid-state fermentation (SSF) using Fusarium oxysporum, Penicillium purpurogenum GH2, Trichoderma harzianum T1-04, and Aspergillus niger GH1 to enhance their antioxidant activity. After fermentation, ethanol extracts were obtained and tested for their antioxidative activity by employing three techniques, 2,2-diphenyl-1-picrylhydrazyl (DPPH˙), ferric reducing antioxidant power (FRAP), and lipid oxidation inhibition (LOI). An increase in antioxidant activity from 33.13 to 41.62 mg/gmsi of antioxidants after fermentation of tangerine by-products by A. niger GH1 was observed. Major compounds present in ethanol extracts obtained after fermentation by A. niger GH1were identified by HPLC-MS, and their m/z corresponded to chlorogenic acid, didymin, naringin, and hesperidin. These results indicated that SSF is a suitable method to enhance antioxidant activity of citrus by-products.

On-line monitoring of Aspergillus niger GH1 growth in a bioprocess for the production of ellagic acid and ellagitannase by solid-state fermentation

The present work describes the monitoring of CO2 production by Aspergillus niger GH1 in a bioprocess for the production of ellagitannase (EAH) and ellagic acid by solid state fermentation. Pomegranate ellagitannins, mainly punicalagin, were used as carbon source and EAH inducer. A second condition, using ellagitannins and maltose as growth promoting carbon source, was tested. The ellagic acid production was quantified and the EAH activity was assayed. The accumulated metabolites were identified by HPLC-ESI-MS/MS. Higher CO2 production (7.79mg/grams of dry material) was reached in media supplemented with maltose. Short-time lag phase (7.79h) and exponential phase (10.42h) were obtained using only ellagitannins, despite its lower CO2 production (3.79mg/grams of dry material). Without the use of maltose lower ellagic acid (11.85mg/L/h) and EAH (21.80U/L/h) productivities were reached. The use of maltose enhances the productivity of EA (33.18mg/L/h) and EAH (33.70U/L/h). Besides of punicalin and ellagic acid, two unknown compounds with mass weight of 702 and 290g/mol (ions 701 and 289m/z in negative mode, respectively) were identified and characterized by HPLC-ESI-MS/MS analysis.

Chapter 5 – Extraction of Bioactive Phenolic Compounds by Alternative Technologies

Extraction of bioactive phenolic compounds (BPCs) from plants, fruits, and their by-products is a topic of interest in the last two decades. The main reason is due to the human health benefits associated with BPC consumption. Alternative extraction technologies have found new applications in the field because of advantages in terms of operational simplicity, safety, and high yields in comparison to conventional extraction technologies. This chapter examines the advances in the research done on BPC extraction using alternative extraction technologies. Modifications to improve the performance of alternative extraction technologies are presented and discussed with focused attention on ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), fermentation-assisted extraction (FAE), and enzyme-assisted extraction (EAE). In addition, the important parameters influencing its performance, the basic theory of reactions present, and the direct effect of alternative extraction technologies on BPCs are included. A list of advantages and drawbacks of the alternative extraction technologies on BPC extraction with regard to conventional extraction technologies is summarized. Finally, a perspective and general conclusion are presented.