Basella alba L. (Malabar Spinach) as an Abundant Source of Betacyanins: Identification, Stability, and Bioactivity Studies on Natural and Processed Fruit Pigments.

The antioxidant and anti-inflammatory activities of acylated and decarboxylated gomphrenins, as well as Basella alba L. fruit extract, were investigated in relation to gomphrenin, known for its high biological potential. The most abundant natural acylated gomphrenins, namely, 6'-O-E-caffeoyl-gomphrenin (malabarin) and 6'-O-E-4-coumaroyl-gomphrenin (globosin), were isolated from B. alba extract for the studies. In addition, controlled thermal decarboxylation of gomphrenin in the purified B. alba extract at 65-75 °C resulted in the formation of the most prevalent decarboxylated products, including 17-decarboxy-gomphrenin and 2,17-bidecarboxy-gomphrenin, along with their isoforms. The structures of the decarboxylated pigments were confirmed by NMR analyses. Exploring the matrix effect on pigment reactivity revealed a tremendous increase in the stability of all betacyanins after the initial stage of extract purification using a cation exchanger under various conditions. This indicates the removal of a substantial portion of the unfavorable matrix from the extract, which presumably contains reactive species that could otherwise degrade the pigments. Furthermore, the high concentration of citrates played a significant role in favoring the formation of 2-decarboxy-gomphrenin to a considerable extent. In vitro screening experiments revealed that the tested compounds demonstrated strong anti-inflammatory properties in lipopolysaccharide (LPS)-activated human macrophages. This effect encompassed the selective inhibition of cytokine and chemokine release from activated macrophages, modulation of the chemotactic activity of immune cells, and the regulation of tissue remodeling mediators' release.

Identification and reactivity of pigments in prominent vegetable leaves of Basella alba L. var. 'Rubra' (Malabar spinach).

The unique profiles of betacyanins as well as their stability and antioxidant activity in purple leaf extracts of the fast-growing, soft-stemmed vine Basella alba L. var. 'Rubra', known as Malabar spinach, are partly characterized for the first time. The distribution of gomphrenin and its acylated derivatives in the leaves is completely different from the profiles of the pigments in the fruits. The most abundant acylated pigment in leaves (24%) turned out 6'-O-E-sinapoyl-gomphrenin (gandolin), however, the most significant difference in the pigment profiles is a presence of two novel pigments tentatively identified as highly abundant 6'-O-(3,4-dimethoxy-E-cinnamoyl)-gomphrenin and 6'-O-(3,4,5-trimethoxy-E-cinnamoyl)-gomphrenin as well as their isoforms. Significant degradation of the pigments in the fruit extracts under the impact of selected metal cations and UV-Vis irradiation as well as high protective activity of the leaf extract matrix were observed. Partial chromatographic purification of the leaf extract resulted in an increase of the pigment concentration which was correlated positively with the increased antioxidant activity of obtained fractions.

Bougainvillea glabra Choisy (Nyctinaginacea): review of phytochemistry and antimicrobial potential.

The Bougainvillea glabra or bougainvillea is a climbing plant native from South America belonging to the Nyctaginaceae family. The bougainvillea is recognized worldwide for its horticultural importance, due to the color of its bracts, commonly known as "flowers," made up of bracts, which are the striking parts, and the true flowers, which are white and small. Bougainvillea is widely known in traditional medicine to treat respiratory diseases such as cough, asthma, and bronchitis, gastrointestinal diseases, also for its antibacterial and insecticidal capacity. The antimicrobial potential of the involucre of this plant has not been studied, despite research showing a high phytochemical presence of secondary metabolites such as alkanes, phenols, terpenes, and betalains. This review compiles information about the traditional uses of B. glabra, its botanical description, ecological relevance, phytochemistry, antimicrobial and antibiofilm activity, such as the toxicology of bracts and flowers.

Development and characterization of a novel active and intelligent film based on pectin and betacyanins from peel waste of pitaya (Hylocereus undatus).

In the present study, peel waste of pitaya (Hylocereus spp.) was used to develop a novel active and functional film. The film was developed with a combination of the white-fleshed pitaya peel pectin (WPPP) as a biopolymer and white-fleshed pitaya peel betacyanins (WPPB) as an active constituent, respectively. Furthermore, montmorillonite (MMT), a cheap and environmental-friendly silicate material, was introduced into film matrix as a filler to reduce the moisture sensitivity of the film. The effect of the incorporation of WPPB on the properties of WPPP/MMT films was investigated. The colorimetric response of WPPP/MMT/WPPB to pH and ammonia was examined, respectively. Moreover, WPPP/MMT/WPPB-2 was employed to monitor the freshness of shrimp. The color of the film changed from redness to reddish-brown, and further to brownness, echoing the shrimp turned from fresh to spoiled. Therefore, WPPP/MMT/WPPB-2 composite films showed promise for the applications in monitoring the freshness of shrimp.

Effect of two-week red beetroot juice consumption on modulation of gut microbiota in healthy human volunteers - A pilot study.

With very little research exploring intestinal effects of red beetroot consumption, the present pilot study investigated gut microbial changes following red beetroot consumption, via a 14-day intervention trial in healthy adults. Compared to baseline, the study demonstrates transient changes in abundance of some taxa e.g., Romboutsia and Christensenella, after different days of intervention (p < 0.05). Enrichment of Akkermansia muciniphila and decrease of Bacteroides fragilis (p < 0.05) were observed after 3 days of juice consumption, followed by restoration in abundance after 14 days. With native betacyanins and catabolites detected in stool after juice consumption, betacyanins were found to correlate positively with Bifidobacterium and Coprococcus, and inversely with Ruminococcus (p < 0.1), potentiating a significant rise in (iso)butyric acid content (172.7 ± 30.9 µmol/g stool). Study findings indicate the potential of red beetroot to influence gut microbial populations and catabolites associated with these changes, emphasizing the potential benefit of red beetroot on intestinal as well as systemic health.

Influence of Citrates and EDTA on Oxidation and Decarboxylation of Betacyanins in Red Beet (Beta vulgaris L.) Betalain-Rich Extract.

The influence of stabilizing activity of citric buffers on betacyanins, as well as their thermal dehydrogenation and decarboxylation in a beetroot betalain-rich extract (BRE), was studied at pH 3-8 and temperature 30, 50 and 85 °C with an additional effect of EDTA. In acetate/phosphate buffers, the highest stability is observed at pH 5 and it decreases toward pH 3 as well as pH 8, which is more remarkable at 85 °C. For the citrates, a contradictory effect was observed. Citric buffers tend to stabilize the substrate pigments and their intermediary products in acidic solutions, although increase their reactivity at pH 6-8. The highest impact of EDTA addition on pigment retention in acetate buffers is observed at 85 °C and pH 3-5 as well as 8, reflecting the preserving activity of EDTA at the most unfavorable conditions. At lower temperatures, pigment stability in more acidic conditions is still at higher levels even without addition of citrates or EDTA. The most striking effect on generation of betanin derivatives during heating is 2-decarboxylation which preferentially proceeds in the most acidic environment and this generation rate at 85 °C is much higher in the citrate buffers compared to acetates.

Composition, Color Stability and Antioxidant Properties of Betalain-Based Extracts from Bracts of Bougainvillea.

Betalains in bracts of Bougainvillea are of great application potential as natural food colorants and antioxidants. This study explored the color, spectra, composition, storage stability, and antioxidant properties of betalain-based Bougainvillea bracts extracts (BBEs) to verify their application value. The results showed that Bougainvillea bract color variance is due to varied contents and proportions of betacyanins (Bc) and betaxanthins (Bx). Bc or Bx alone determined hues of purple or yellow, respectively; the co-existence of Bc and Bx would produce varied hues of red. BBEs showed bright color and good antioxidant properties under a wide pH range. The pH range of 5−6 was optimal for the highest color stability, and pHs 3−8 were optimal for stronger antioxidants. Bc mainly underwent color fading during storage, while Bx easily produced dark precipitates or melanism under strong acidic (pH < 4) or alkaline conditions (pH > 8). However, Bougainvillea Bx showed 3−4 times higher antioxidant ability than Bc. Different considerations for Bc and Bx are needed for varied application purposes. The purple bracts containing only Bc would be more suitable as colorant sources, while additional Bx can bring enhancement of antioxidant ability and richness of Bougainvillea extract color.

Betacyanins are plant-based dyes with potential as histological stains.

Interest is increasing in certain parts of the world in replacing synthetic dyes with dyes from natural sources, particularly from plants. Although textile dyers have used various groups of natural dyes, microscopists generally have restricted their use to anthocyanins. Recently, however, another class of plant-based dyes has found some favor, the betacyanins. Betacyanins are a group of red and violet betalain dyes found only in certain plants of the order Caryophyalles and in Basidiomycetes mushrooms. Although the chemical structures of betacyanins are known, little use has been made of that information to understand or predict their behavior with biomedical specimens. We investigated two common, widely distributed betacyanin-containing plants, edible beets (Beta vulgaris) and wild pokeweed (Phytolacca americana). Aqueous alcoholic extracts were made from beet root and pokeweed berries, adjusted to pH 4.1 or 5.3 and used together with Harris' hematoxylin to stain histological sections. We used a methanolic extract of pokeweed berries, pH 3.0, to stain cultured mycological specimens. Both extracts produced satisfactory staining that was equivalent to that of eosin Y, although the colors were more muted with the beet root extract. Epithelial cytoplasm, muscle, collagen and erythrocytes were well demonstrated. Betanin is the predominant component of beet root extract; it possesses one delocalized positive charge and three carboxylic acid substituents. The dyes are weak acids and the carboxylate anions are more diffuse than for eosin Y; this produces weaker bonding to tissue cations. The principal colored component of pokeweed berries, prebetanin, possesses a sulfonic acid group as well as carboxylic acids, which favors acid dyeing and more intense coloration. Both dyes show potential for hydrogen bonding and to a much lesser extent for some types of van der Waals forces. Complex formation with metals such as aluminum to create a nuclear stain is not likely with beet root dyes nor is it possible with pokeweed dyes. Betacyanins are suitable for staining microscopy preparations in place of other red acid dyes such as eosin. Of the two dyes tested here, prebetanin from pokeweed berries was superior to betanin from red beet roots. These berries are widely distributed and readily collected; the extraction procedure is simple and does not require expensive solvents.

Dehydrogenation of Betacyanins in Heated Betalain-Rich Extracts of Red Beet (Beta vulgaris L.).

Betacyanins are a group of water-soluble red-violet compounds containing nitrogen in their structure. These are biosynthesized in red beetroot (Beta vulgaris L.), a widely consumed vegetable that contains significant amounts of nutritious and bioactive compounds which are also found in dietary supplements. This contribution presents results of betacyanin thermal oxidation (resulting in dehydrogenation) interrelated with decarboxylation in selected acetate/phosphate buffers at pH 3-8 and at 85 °C, which may be of particular significance for formulation and performance of foods. Most of the reaction products were detected at the highest concentrations in the acidic solutions (pH 3-4). The main dehydrogenation reaction pathways were monitored by LC-DAD-MS/MS and were associated with decarboxylation of the principal extract pigments, betanin/isobetanin and neobetanin, at carbon positions C-2 and C-17. Additional reactions are accompanied by the 2,15-decarboxylation processes at different dehydrogenation levels with 15-decarboxy-betanin and 2,15-bidecarboxy-betanin, structurally elucidated by NMR analysis, as the distinct indicators of this route type. For other novel pigments detected, 2,15-bidecarboxy-xanbetanin, 2,15-bidecarboxy-xanneobetanin and 2,15,17-tridecarboxy-neobetanin, additional high resolution mass spectrometric analyses were performed and confirmed their molecular formulas.

Red pitaya (Hylocereus costaricensis) peel as a source of valuable molecules: Extraction optimization to recover natural colouring agents.

Hylocereus costaricensis peel contains large amounts of betacyanins and can be exploited as a source of natural colorants. This work aimed the chemical characterization and evaluation of bioactive properties of this by-product and the optimization of the ultrasound-assisted extraction (UAE) of betacyanins using the response surface methodology (RSM). Oxalic and malic acids and traces of fumaric acid were detected, as well as the four tocopherol isoforms, predominantly γ-tocopherol. Four betacyanins were identified and used as response criteria for UAE optimization, namely phyllocactin, isobetanin, isophyllocactin, and betanin. Sample processing at 487 W for 38 min result in the maximum betacyanin content (36 ± 1 mg/g dw). The peel extract inhibit the oxidative haemolysis, with IC50 values of 255 and 381 µg/mL for Δt of 60 and 120 min, respectively, and the growth of pathogenic bacteria, with minimum inhibitory concentrations ranging from 5 to 20 mg/mL. Furthermore, no toxicity was observed for normal cells.

The Compositional Aspects of Edible Flowers as an Emerging Horticultural Product.

Edible flowers are becoming very popular, as consumers are seeking healthier and more attractive food products that can improve their diet aesthetics and diversify their dietary sources of micronutrients. The great variety of flowers that can be eaten is also associated with high variability in chemical composition, especially in bioactive compounds content that may significantly contribute to human health. The advanced analytical techniques allowed us to reveal the chemical composition of edible flowers and identify new compounds and effects that were not known until recently. Considering the numerous species of edible flowers, the present review aims to categorize the various species depending on their chemical composition and also to present the main groups of compounds that are usually present in the species that are most commonly used for culinary purposes. Moreover, special attention is given to those species that contain potentially toxic or poisonous compounds as their integration in human diets should be carefully considered. In conclusion, the present review provides useful information regarding the chemical composition and the main groups of chemical compounds that are present in the flowers of the most common species.

Bioactive Betalain Extracts from Cactus Pear Fruit Pulp, Beetroot Tubers, and Amaranth Leaves.

Natural food items and the additional benefits they provide have received considerable attention in recent years. Betalains are nutritious pigments which have valuable biological properties, e.g., antioxidant and free radical scavenging activity. In this study, aqueous betalain extracts were obtained from different coloured cactus pears (purple, red/pink, and orange), amaranth, and beetroot, with and without the addition of ascorbic acid, microwave-heated, and freeze-dried and subsequently analysed by thin layer chromatography (TLC). Beetroot samples without the addition of ascorbic acid (AA) had lower phenols, flavonoids, and ascorbic acid content than beetroot samples extracted with the addition of AA. Amaranth had significantly higher contents of antioxidants than all the other plants. Results for phenolic compounds showed that there were no significant differences between cactus pear cultivars, however, significant differences were seen between the two beetroot samples (microwave-heated with and without AA) as well as amaranth. For flavonoid compounds, amaranth had significantly higher values than all other samples. The lowest flavonoid content was found in beetroot without AA (0.49 mgCE/g). For ascorbic acid, significant differences were noticed between amaranth (71.71 mg/100 g) and samples from cactus pear and beetroot. TLC results showed that purple and red cactus pear samples had the most vivid colours, a reflection of the high betacyanin and betaxanthin contents in the cultivars. Moreover, extracts from cactus pear, beetroot, and amaranth were classified according to a decision tree which was designed by the Code of Federal Regulations/Food Additives Regulation of the EU. The classification of betalain pigment extracts as colouring foods was achieved through enrichment factor calculations and the colourant decision tree. The results showed that the betalain pigment extraction method used is inexpensive, time-saving, energy-saving, non-toxic, and chemical solvent free and yields high concentrations of betalains.

Betalain Extracts from Beetroot as Food Colorants: Effect of Temperature and UV-Light on Storability.

Beetroot is a good source of natural food colorants given that it contains significant amount of betalain pigments. This study investigates the three-months storage stability of betalain extracts recovered from unsold beetroot by a specific enzymatic mix. The extract storability was evaluated by the kinetic degradation model of betacyanins and betaxanthins, as well as by pigment color attributes (CIELa*b* parameters) under dark and UV-light exposure at different temperatures (4, 25 and 40 °C). Considering all the tested storage conditions, betaxanthins appeared to be more stable than betacyanins in terms of degradation rate constant, half-life time and activation energy. The effect of UV-light was negligible if the pigment was not exposed to temperatures higher than the room one, since no relevant differences were found between the parameters studied at 4 and 25 °C. Taking into account the visual color, all the investigated color indexes (total color difference, chroma and hue) were mainly affected by temperature, even if mildly high (40 °C), and to a lesser extent by UV-light exposure.

The impacts of peel inclusion and fermentation temperature on the bioactive compounds, antioxidant activity, and sensory properties of dragon fruit wines.

BACKGROUND: Even though dragon fruit peel has more health benefits than its pulp, it is considered to be waste after fruit processing. In this study, dragon fruit peel was explored as an additional ingredient in winemaking. METHODS: The contents of total phenolic compounds, betacyanins and ascorbic acid, the antioxidant capacity by DPPHz method, and the level of consumer acceptability of the wines prepared from two species with and without peel were compared. RESULTS: The wines of the H. polyrhizus species contained much higher total phenolics (1.4-1.6 times), betacyanins (75-81 times), and vitamin C (2.8-3.8 times), as well as higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (1.2 times) than the wines of H. undatus. Although the fermentation process led to the degradation of betacyanins, it increased the total phenolics (up to 17%), vitamin C (up to 24%), and DPPHz scavenging activity (up to 19%) as compared with the control when fermentation was conducted at 25°C, which was found as the most suitable fermentation temperature to produce wines with the highest quality in terms of antioxidant content and activity. At this temperature, peel inclusion also increased these values in the wine. In addition, the sensory properties in terms of appearance and aroma could be improved in the final fermented product. CONCLUSIONS: H. polyrhizus wine might have higher antioxidant properties than H. undatus wine. With a suitable fermentation temperature, peel inclusion as an ingredient could enhance these characteristics of the wine without compromising its sensory quality. This study may provide insights into fruit winemaking with higher health benefits.

Development of active and smart packaging films based on starch, polyvinyl alcohol and betacyanins from different plant sources.

In this study, active and smart packaging films were prepared by individually adding betacyanins-rich plant extracts (red pitaya flesh extract (RPFE), prickly pear fruit extract (PPFE), red beetroot extract (RBRE), globe amaranth flower extract (GAFE) and red amaranth leaf extract (RALE)) into starch/polyvinyl alcohol. The structural, physical and functional properties of the films containing betacyanins from different plant sources were compared for the first time. Results showed betacyanins from RPFE, PPFE and RBRE were betanin-type betacyanins. Betacyanins from GAFE and RALE were gomphrenin-type and amaranthin-type betacyanins, respectively. The films containing RPFE and PPFE presented more uniform cross-sections and had the highest water vapor barrier (9.37 and 9.26 × 10-11 g m-1 s-1 Pa-1) and mechanical strength (8.26 and 7.87 MPa). However, the film containing GAFE presented the lowest light transmittance but the highest 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (EC50 = 0.47 mg/mL). All the films containing betacyanins are sensitive to pH 8-12 buffer solutions and volatile ammonia. Notably, the film containing RPFE exhibited distinct color changes (from purple-red to pink) when shrimp spoiled. Our results suggest the structural, physical and functional properties of betacyanins-rich films are closely related to the source and type of betacyanins.

The Responses of Bioactive Betanin Pigment and Its Derivatives from a Red Beetroot (Beta vulgaris L.) Betalain-Rich Extract to Hypochlorous Acid.

Neutrophils produce hypochlorous acid (HOCl) as well as other reactive oxygen species as part of a natural innate immune response in the human body; however, excessive levels of HOCl can ultimately be detrimental to health. Recent reports suggest that betacyanin plant pigments can act as potent scavengers of inflammatory factors and are notably effective against HOCl. Comparison of the in vitro anti-hypochlorite activities of a novel betalain-rich red beetroot (Beta vulgaris L.) extract with its pure betalainic pigments revealed that the extract had the highest anti-hypochlorite activity, far exceeding the activity of all of the betalainic derivatives and selected reference antioxidants. This suggests that it may be an important food-based candidate for management of inflammatory conditions induced by excessive HOCl production. Among all pigments studied, betanidin exhibited the highest activity across the pH range.

Betacyanins, major components in Opuntia red-purple fruits, protect against acetaminophen-induced acute liver failure.

Acetaminophen (APAP) misuse or overdose is the most important cause of drug-induced acute liver failure. Overdoses of acetaminophen induce oxidative stress and liver injury by the electrophilic metabolite N-acetyl-p-benzoquinone imine (NAPQI). Plant-based medicine has been used for centuries against diseases or intoxications due to their biological activities. The aim of this study was to evaluate the therapeutic value of Opuntia robusta and Opuntia streptacantha fruit extracts against acetaminophen-induced liver damage and to identify the major biocomponents on them. Opuntia fruit extracts were obtained by peeling and squeezing each specie, followed by lyophilization. HPLC was used to characterize the extracts. The effect of the extracts against acetaminophen-induced acute liver injury was evaluated both in vivo and in vitro using biochemical, molecular and histological determinations. The results showed that betacyanins are the main components in the analyzed Opuntia fruit extracts, with betanin as the highest concentration. Therapeutic treatments with Opuntia extracts reduced biochemical, molecular and histological markers of liver (in vivo) and hepatocyte (in vitro) injury. Opuntia extracts reduced the APAP-increased expression of the stress-related gene Gadd45b. Furthermore, Opuntia extracts exerted diverse effects on the antioxidant related genes Sod2, Gclc and Hmox1, independent of their ROS-scavenging ability. Therefore, betacyanins as betanin from Opuntia robusta and Opuntia streptacantha fruits are promising nutraceutical compounds against oxidative liver damage.

Identification and Determination of Betacyanins in Fruit Extracts of Melocactus Species.

Betacyanin pigments were studied in edible fruits of four Melocactus species, M. violaceus Pfeiff., M. bahiensis (Britton & Rose) Luetzelb, M. amoenus (Hoffm.) Pfeiff., and M. curvispinus Pfeiff., by means of chromatographic and mass spectrometric techniques. The main pigment constituent, melocactin, endogenously present in the Melocactus species, was identified as betanidin 5-O-ß-sophoroside betacyanin, previously known as "bougainvillein-r-I". The highest total concentration of betacyanins was found in fruits of M. amoenus (∼0.08 mg/g). Except for melocactin being the most abundant betacyanin (34.8-38.8%) in the analyzed species, a presence of its malonylated derivative, mammillarinin (15.2-19.9%), as well as more hydrophobic feruloyled and sinapoyled melocactins was confirmed by additional co-chromatographic experiments with authentic reference betacyanins. The acyl migration isomers of the malonylated betacyanins as well as a presence of 5''-O-E-sinapoyl-2'-O-apiosyl-betanin (2.3-3.0%) found frequently in light-stressed cacti was also acknowledged.

Separation of betacyanins from Iresine herbstii Hook. ex Lindl. leaves by high-speed countercurrent chromatography in a polar solvent system.

Betacyanins, natural plant pigments, from Iresine herbstii Hook. ex Lindl. leaf extract were separated for the first time by high-speed countercurrent chromatography (HSCCC) in a highly polar solvent system composed of PrOH-ACN-(NH4)2SO4satd.soln-H2O (1.0:0.5:1.2:1.0; v/v/v/v) in the tail-to-head mode. The flow rate of the mobile phase was 2.0 ml/min and the column rotation speed was 860 rpm. The retention of the stationary phase was 81.0%. For the identification of separated betacyanins in the crude extract and in the HSCCC fractions, as well as for the molecular formulas and multi-step fragmentation pattern elucidation, liquid chromatography with tandem mass spectrometry and high-resolution ion-trap time-of-flight mass spectrometry were performed. The innovative application of the HSCCC system for fractionation of the betacyanins present in I. herbstii leaves enabled effective separation as well as preconcentration of the pigments for further low- and high-resolution LC-MS/MS analysis. HSCCC separation enabled identification of 22 betacyanins, of which 18 had not been detected previously in the leaves of I. herbstii, and four of these betacyanins (sinapoyl-gomphrenin and coumaroyl-gomphrenin as well as their epimers) were identified for the first time in the Iresine genus.

Betacyanins from Gomphrena globosa L. flowers: Incorporation in cookies as natural colouring agents.

A betacyanin rich extract was obtained from the flowers of Gomphrena globosa L. by ultrasound-assisted extraction and dried either by lyophilization or spray-drying, was tested as a natural colourant in cookies and compared to a commercial colourant. The extracts were characterized in terms of betacyanin content and antioxidant potential. The effects of the colourants incorporation in the cookies were assessed through proximate composition, soluble sugars, fatty acids, color, texture and microbial load, over a shelf life of 30 days. Considering all the assays and analyzing the results through a 2-way analysis of variance, the cookies incorporated with spray-dried colourant showed the most intense pink coloration while cookies incorporated with lyophilized extract lost less color intensity over time. Thus, betacyanin extracts have potential as pink natural alternatives to synthetic colourants in the food industry.