Chemical characterization of yellow-orange and purple varieties of Opuntia ficus-indica fruits and thermal stability of their betalains.

Betalains are plant pigments with biological properties and can be used instead of synthetic colorants to confer color and functional properties to foods. The objective of this work was to carry out the chemical characterization of two varieties of prickly pear of Opuntia ficus-indica, one of yellow-orange coloration (Mandarina) and the other of purple coloration (Vigor), through measurements of chemical parameters and color in pulp, antioxidant activity, total phenolic compounds, and betalain content. Considering the thermolability of betalains and their potential applications in food, the thermal stability and activation energy of betacyanins from Vigor variety and betaxanthins from the Mandarina variety were also evaluated and compared with those from beetroot, the main source of betalains. Results for chemical characterization agreed with previous prickly pear reports of other regions, while the thermal degradation kinetics of betalains showed a first-order degradation pattern with respect to time and temperature treatment. Betacyanins from Vigor prickly pear showed similar thermal stability to those from beetroot, which was reflected in similar values of activation energy, while betaxanthins from Mandarina prickly pear showed a higher stability, and therefore a higher activation energy, than those from beetroot. Based on the results, the prickly pear varieties used in this study can be considered as a good source of betalains with potential applications in food and, in addition, the methodology for the evaluation of thermostability can be used to compare the stability of betalains from different sources in a temperature range of 50-90°C. PRACTICAL APPLICATION: The varieties of prickly pear used in this study can be considered a good source of red-purple and yellow-orange easily extractable pigments. In addition, we report a methodology that can be used for the evaluation of the thermal stability of these pigments and to compare this stability between different plant sources. Gaining knowledge on betalain thermal stability will make it possible to propose specific applications, for example, in processed foods requiring different pigment stabilities.

Antimutagenic, Antiproliferative and Antioxidant Properties of Sea Grape Leaf Extract Fractions (Coccoloba uvifera L.).

BACKGROUND: Cancer is a disease characterized by the invasion and uncontrolled growth of cells. One of the best ways to minimize the harmful effects of mutagens is through the use of natural antimutagens. In this regard, the search for new antimutagens that act in the chemoprevention could represent a promising field in this area. OBJECTIVE: In this study biological potential of 11 fractions from Coccoloba uvifera L. leaf hexane extract was evaluated by several in vitro tests. METHODS: Leaves were lyophilized and hexane extraction was performed. The extract was fractionated by column chromatography with hexane, ethyl acetate, and methanol. The antimutagenic (Ames test), antiproliferative (MTT test), and antioxidant capacity (DPPH, ABTS, and ferrous ion chelation) of the fractions were evaluated. RESULTS: Fractions 4, 6, 8, and 9 have antimutagenic activity (against sodium azide in strain TA100), fraction 11 showed antiproliferative capacity (IC50 of 24 ± 9 µg/mL in cells of HCT 116). The fractions with the highest activity were analyzed by HPLC-MS and lupeol, acacetin, and ß-sitosterol were identified. CONCLUSION: This study demonstrates, for the first time, the bioactivity of C. uvifera leaf as a new source of High Biological Value Compounds (HBVC), which can be of interest to the food and pharmaceutical industries.

Caffeoylquinic Acid Derivatives of Purple Sweet Potato as Modulators of Mitochondrial Function in Mouse Primary Hepatocytes.

Owing to their antioxidant properties, caffeoylquinic acid (CQA)-derivatives could potentially improve the impaired metabolism in hepatic cells, however, their effect on mitochondrial function has not been demonstrated yet. Here, we evaluated the impact of three CQA-derivatives extracted from purple sweet potato, namely 5-CQA, 3,4- and 4,5-diCQA, on mitochondrial activity in primary hepatocytes using an extracellular flux analyzer. Notably, an increase of maximal respiration and spare respiratory capacity were observed when 5-CQA and 3,4-diCQA were added to the system indicating the improved mitochondrial function. Moreover, 3,4-diCQA was shown to considerably increase glycolytic reserve which is a measure of cell capability to respond to an energy demand through glycolysis. Conversely, 4,5-diCQA did not modify mitochondrial activity but increased glycolysis at low concentration in primary hepatocytes. All compounds tested improved cellular capacity to oxidize fatty acids. Overall, our results demonstrated the potential of test CQA-derivatives to modify mitochondrial function in hepatic cells. It is especially relevant in case of dysfunctional mitochondria in hepatocytes linked to hepatic steatosis during obesity, diabetes, and metabolic syndrome.

Achiote (Bixa orellana) Lipophilic Extract, Bixin, and δ-tocotrienol Effects on Lifespan and Stress Resistance in Caenorhabditis elegans.

The onset of many degenerative diseases related to aging has been associated with a decrease in the activity of antistress systems, and pharmacological interventions increasing stress resistance could be effective to prevent the development of such diseases. Achiote is a valuable source of carotenoid and tocotrienols, which have antioxidant activity. In this work, we explore the capacity of an achiote seed extract and its main compounds to modulate the lifespan and antistress responses on Caenorhabditis elegans, as well as the mechanisms involved in these effects. Achiote lipophilic extract, bixin, and δ-tocotrienol were applied on nematodes to carry out lifespan, stress resistance, and fertility assays. The achiote seed extract increased the median and maximum lifespan up to 35% and 27% and increased resistance against oxidative and thermal stresses without adverse effects on fertility. The beneficial effects were mimicked by a bixin+δ-tocotrienol mixture. All the effects on lifespan and stress resistance were independent of caloric restriction but dependent on the insulin/insulin growth factor-1 pathway. This study could provide insights for further research on a new beneficial use of this important crop in health and nutraceutical applications beyond its use as a source of natural pigments.

New acylated cyanidin glycosides extracted from underutilized potential sources: Enzymatic synthesis, antioxidant activity and thermostability.

Interest in anthocyanins has increased remarkably in recent decades, although their wider application has been hampered by instability problems. Thus, this study aimed at developing a strategy to gain access to more stable anthocyanins via enzymatic esterification. For that purpose, three cyanidin derivatives were obtained from underutilized, but easily accessible sources, and their total anthocyanin content was quantified. The purity of cyanidins obtained ranged from 40% to 88% depending on their source. Subsequently, the critical enzymatic reaction conditions were established, and the best results were found using tert-butanol as a solvent, 20 g/L of lipase B from Candida Antarctica, and vinyl cinnamate as acyl donor at ratio 250:1 (acyl donor to anthocyanin). Finally, five new acylated anthocyanin derivatives were synthesized with improved antioxidant activity and thermostability, in comparison to the cyanidin-3-glucoside, which is an advantageous feature for industrial applications.

Goats' Feeding Supplementation with Acacia farnesiana Pods and Their Relationship with Milk Composition: Fatty Acids, Polyphenols, and Antioxidant Activity.

BACKGROUND: Research efforts have focused on the evaluation of the bioactive quality of animal products (milk, cheese, meat, and other by-products) contrasting various feeding strategies coming from different ecological zones. The study aimed to describe the fatty acids (FA), polyphenols (P), bioactive compounds (BC), and antioxidant activity (AA) of goat's milk. METHODS: Dairy goats were fed with five systems: (1) Grazing; (2) conventional diet (CD); (3) CD + 10% of Acacia farnesiana (AF) pods; (4) CD + 20% AF; and (5) CD + 30% AF. The fatty acid profile, health promoting and thrombogenic indexes were calculated. Milk extracts were evaluated by HPLC to determent phenolic compounds (gallic, caffeic, chlorogenic, and ferulic acids, catechin, epicatechin, and quercetin). Antioxidant activity of goat's milk extract was evaluated using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•), oxygen radical absorbance capacity (ORAC), and the ferric reducing antioxidant power (FRAP) assays. RESULTS: Conventional diet showed the highest content of polyunsaturated fatty acids while grazing showed the best n-6:n-3 and the linoleic:alpha linolenic acid ratio. Similarly, grazing and AF boosted the polyphenol content. CONCLUSIONS: Acacia farnesiana inclusion in the goats' diets increased the presence of bioactive compounds and the antioxidant activity while diminishing the cholesterol content of goat's milk.

Extraction and Identification of Anthocyanins in Corn Cob and Corn Husk from Cacahuacintle Maize.

Pigmented maize has been extensively studied due to its high anthocyanin content. This study has been focused mainly on kernel, although the whole plant of purple corn is a potential source of anthocyanins. First, general parameters of extraction (solvent system, solvent-to-solid ratio, number of extractions, and acid type) were established depending on the total anthocyanins content. Then, three extraction methods to access anthocyanins were compared: maceration extraction (ME), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE). Since the residual material still possessed an intense color, a further treatment was performed by application of enzymatic-assisted extraction (EAE). Three enzymatic cocktails (Xylanases, Celluclast, and Depol), pH, and temperature were evaluated to establish optimal reaction conditions. Subsequent analysis and identification of the anthocyanins obtained by four different extraction techniques were performed using HPLC and HPLC-mass spectrometry, respectively. The most efficient method was UAE using 20 min of ultrasound (100 W) preceded by sample treatment in the following conditions: ethanol/water/lactic acid mixture (80:19:1), two extractions, 1:10 solvent-to-solid ratio. As a result, anthocyanins from corn cob and corn husk were extracted at concentrations of 24.32 and 25.80 mg/gDW, respectively. No difference in the anthocyanins profile for samples extracted by three different methods was observed. However, an enhanced presence of cyanidin-3-(6''malonyl)glucoside was detected in the sample corresponding to the EAE method. Therefore, the Cahuacintle corn husk can be considered as a competitive source of anthocyanins with the available commercial sources. PRACTICAL APPLICATION: The by-products obtained from Cacahuacintle purple corn can be potentially used as natural colorants thanks to their anthocyanins content. In this work, we established the most efficient extraction method of anthocyanins from corn husk and corn cob, and demonstrated that their anthocyanins profile is comparable to other Peruvian purple corns, which are currently used as natural colorants. Therefore, the extraction procedure described in this study might be scaled-up in an industrial process to get access to anthocyanins from undervalued wastes.

ANCUT2, an extracellular cutinase from Aspergillus nidulans induced by olive oil.

Cutinases are versatile carboxylic ester hydrolases with great potential in many biocatalytic processes, including biodiesel production. Genome sequence analysis of the model organism Aspergillus nidulans reveals four genes encoding putative cutinases. In this work, we purified and identified for the first time a cutinase (ANCUT2) produced by A. nidulans. ANCUT2 is a 29-kDa protein which consists of 255 amino acid residues. Comparison of the amino acid sequence of ANCUT2 with other microbial cutinase sequences revealed a high degree of homology with other fungal cutinases as well as new features, which include a serine-rich region and conserved cysteines. Cutinase production with different lipidic and carbon sources was also explored. Enzyme activity was induced by olive oil and some triacylglycerides and fatty acids, whereas it was repressed by glucose (1%) and other sugars. In some conditions, a 22-kDa post-translational processing product was also detected. The cutinase nature of the enzyme was confirmed after degradation of apple cutin.

Conversion of alpha-amyrin into centellosides by plant cell cultures of Centella asiatica.

Plant cell cultures of Centella asiatica produce small quantities of centellosides: madecassosid > asiaticosid > madecassic acid > asiatic acid. To obtain a more efficient production system of these bioactive triterpenoid compounds, we developed a process where the substrate, alpha-amyrin, was converted into centellosides by cell suspensions of C. asiatica. When alpha-amyrin in acetone was added at 0.01 mg/ml(-1) to the culture medium, together with the permeabilizing agent DMSO, after 7 days nearly 50% had penetrated the plant cells, of which almost 84% was transformed into centellosides. The system therefore efficiently converts alpha-amyrin into centellosides, thus opening a new possibility for the production of these compounds.