Phytochemical composition and biological activities of differently pigmented cabbage (Brassica oleracea var. capitata) and cauliflower (Brassica oleracea var. botrytis) varieties

Medicinal plants used for cutaneous wound healing in Uganda; ethnomedicinal reports and pharmacological evidences

Background

Wounds have become a major health challenge worldwide, presenting marked humanistic and economic burdens such as disabilities and death. Annually, approximately 14 million people suffer from wounds worldwide and 80 % of these occur in developing countries like Uganda. In Uganda, besides many cases of daily wound occurrences, approximately 10 % of surgical procedures become septic wounds and consequently lead to increased morbidity and mortality. Accordingly, several ethnomedicinal studies have identified plants used for wound treatment in different parts of Uganda and the wound healing activities of some plants have been reported. However, at present, these information remain largely separated without an all-inclusive repository containing ethnomedicinal and pharmacological information of the plants used for wound healing in Uganda, thus retarding appropriate evaluation. Therefore, this review focused on extensively exploring the plants used for treating cutaneous wounds in Uganda, along with associated ethnomedicinal information and their globally reported pharmacological potential.

Methods

Electronic data bases including Google Scholar, PubMed, and Science Direct were searched using key terms for required information contained in English peer reviewed articles, books, and dissertations. Additionally, correlations between selected parameters were determined with coefficient of determination (r2).

Results

The literature survey revealed that 165 species belonging to 62 families are traditionally used to treat wounds in Uganda. Most of the species belonged to families of Asteraceae (14 %), Fabaceae (10 %), and Euphorbiaceae (7 %). The commonest plant parts used for wound treatment include leaf (48 %), root (22 %), stembark (11 %), and stem (7 %), which are prepared majorly by poultice (34 %), decoction (13 %), as well as powdering (25 %). Fifty-four (33 %) of the plant species have been investigated for their wound healing activities whereas, one hundred eleven (67 %) have not been scientifically investigated for their wound healing effects. Pearson correlation coefficient between the number of wound healing plant families per part used and percent of each plant part used was 0.97, and between the number of wound healing plant families per method of preparation and percent of each method of preparation was 0.95, showing in both strong positively marked relationships.

Conclusion

The preliminarily investigated plants with positive wound healing properties require further evaluation to possible final phases, with comprehensive identification of constituent bioactive agents. Additionally, the wound healing potential of the scientifically uninvestigated plants with claimed healing effects needs examination. Subsequently, information regarding efficacy, safety, bioactive principles, and mechanism of action could prove valuable in future development of wound healing therapies.

Widely-targeted metabolomics and transcriptomics identify metabolites associated with flowering regulation of Choy Sum

Choy Sum, a stalk vegetable highly valued in East and Southeast Asia, is characterized by its rich flavor and nutritional profile. Metabolite accumulation is a key factor in Choy Sum stalk development; however, no research has focused on metabolic changes during the development of Choy Sum, especially in shoot tip metabolites, and their effects on growth and flowering. Therefore, in the present study, we used a widely targeted metabolomic approach to analyze metabolites in Choy Sum stalks at the seedling (S1), bolting (S3), and flowering (S5) stages. In total, we identified 493 metabolites in 31 chemical categories across all three developmental stages. We found that the levels of most carbohydrates and amino acids increased during stalk development and peaked at S5. Moreover, the accumulation of amino acids and their metabolites was closely related to G6P, whereas the expression of flowering genes was closely related to the content of T6P, which may promote flowering by upregulating the expressions of BcSOC1, BcAP1, and BcSPL5. The results of this study contribute to our understanding of the relationship between the accumulation of stem tip substances during development and flowering and of the regulatory mechanisms of stalk development in Choy Sum and other related species.

Volatile/semi-volatile metabolites profiling in living vegetables via a novel covalent triazine framework based solid-phase microextraction fiber coupled with GC-QTOF-MS

An in vivo solid-phase microextraction (SPME) fiber with high-coverage capture capacity of plant endogenous substances based on the porous covalent triazine framework (CTF) material was developed. The CTF fiber coupled with gas chromatographic quadrupole time-of-flight mass spectrometer (GC-QTOF-MS) analysis was used for monitoring untargeted endogenous metabolites in living Chinese cabbage plants (Brassica campestris L. ssp. chinensis Makino (var. communis Tsen et Lee)). A total of 100 endogenous substances were identified, mainly including aldehydes, ketones, acids, alcohols, phenols, alkanes, alkenes, esters, isorhodanates, nitriles, as well as indole and its derivatives. Using the in vivo metabolites analysis method, Chinese cabbage plants at different growing stages demonstrated significantly statistical differences in plant metabolism. In addition, metabolic dysregulation of Chinese cabbage plants under fipronil pesticide contamination was observed. To summarize, the proposed approach provides a feasible method to capture metabolic information in living vegetables and for risk assessment of pesticide use during agricultural production.

Hypericum alpestre extract exhibits in vitro and in vivo anticancer properties by regulating the cellular antioxidant system and metabolic pathway of L-arginine

Conventional treatment methods are not effective enough to fight the rapid increase in cancer cases. The interest is increasing in the investigation of herbal sources for the development of new anticancer therapeutics. This study aims to investigate the antitumor capacity of Hypericum alpestre (H. alpestre) extract in vitro and in vivo, either alone or in combination with the inhibitors of the  l-arginine/polyamine/nitric oxide (NO) pathway, and to characterize its active phytochemicals using advanced chromatographic techniques. Our previous reports suggest beneficial effects of the arginase inhibitor NG-hydroxy-nor- l-arginine and NO inhibitor NG-nitro-Larginine methyl ester in the treatment of breast cancer via downregulation of polyamine and NO synthesis. Here, the antitumor properties of H. alpestre and its combinations were explored in vivo, in a rat model of mammary gland carcinogenesis induced by subcutaneous injection of 7,12-dimethylbenz[a]anthracene. The study revealed strong antiradical activity of H. alpestre aerial part extract in chemical (DPPH/ABTS) tests. In the in vitro antioxidant activity test, the H. alpestre extract demonstrated pro-oxidant characteristics in human colorectal (HT29) cells, which were contingent upon the hemostatic condition of the cells. The H. alpestre extract expressed a cytotoxic effect on HT29 and breast cancer (MCF-7) cells measured by the MTT test. According to comet assay results, H. alpestre extract did not exhibit genotoxic activity nor possessed antigenotoxic properties in HT29 cells. Overall, 233 substances have been identified and annotated in H. alpestre extract using the LC-Q-Orbitrap HRMS system. In vivo experiments using rat breast cancer models revealed that the H. alpestre extract activated the antioxidant enzymes in the liver, brain, and tumors. H. alpestre combined with chemotherapeutic agents attenuated cancer-like histological alterations and showed significant reductions in tumor blood vessel area. Thus, either alone or in combination with Nω -OH-nor- l-arginine and Nω -nitro- l-arginine methyl ester, H. alpestre extract exhibits pro- and antioxidant, antiangiogenic, and cytotoxic effects.

Assessment of Bio-Compounds Content, Antioxidant Activity, and Neuroprotective Effect of Red Cabbage (Brassica oleracea var. Capitata rubra) Processed by Convective Drying at Different Temperatures

Parkinson's disease (PD) is the second most common neurodegenerative disorder, and no efficient therapy able to cure or slow down PD is available. In this study, dehydrated red cabbage was evaluated as a novel source of bio-compounds with neuroprotective capacity. Convective drying was carried out at different temperatures. Total phenolics (TPC), flavonoids (TFC), anthocyanins (TAC), and glucosinolates (TGC) were determined using spectrophotometry, amino acid profile by LC-DAD and fatty acid profile by GC-FID. Phenolic characterization was determined by liquid chromatography-high-resolution mass spectrometry. Cytotoxicity and neuroprotection assays were evaluated in SH-SY5Y human cells, observing the effect on preformed fibrils of α-synuclein. Drying kinetic confirmed a shorter processing time with temperature increase. A high concentration of bio-compounds was observed, especially at 90 °C, with TPC = 1544.04 ± 11.4 mg GAE/100 g, TFC = 690.87 ± 4.0 mg QE/100 g and TGC = 5244.9 ± 260.2 µmol SngE/100 g. TAC degraded with temperature. Glutamic acid and arginine were predominant. Fatty acid profiles were relatively stable and were found to be mostly C18:3n3. The neochlorogenic acid was predominant. The extracts had no cytotoxicity and showed a neuroprotective effect at 24 h testing, which can extend in some cases to 48 h. The present findings underpin the use of red cabbage as a functional food ingredient.

Relationship between Chemical Structure and Biological Activity Evaluated In Vitro for Six Anthocyanidins Most Commonly Occurring in Edible Plants

Numerous studies have provided evidence that diets rich in anthocyanins show a broad spectrum of health benefits. Anthocyanins in nature are usually found in the form of glycosides. Their aglycone forms are called anthocyanidins. The chemical structure of anthocyanins is based on the flavylium cation, but they differ in the position and number of substituents. However, the bioactives and foods that contain them are frequently treated as a uniform group of compounds exhibiting the same biological activity, without paying attention to the structural differences between individual anthocyanidins. The aim of this study was to find out how structural differences impact the biological activity of the six most common dietary anthocyanidins, i.e., delphinidin (Dp), petunidin (Pt), cyanidin (Cd), malvidin (Mv), pelargonidin (Pg) and peonidin (Po). The study concentrated on redox-related phenomena and compared the following parameters: antioxidant activity (measured using various methods: spectrophotometric tests (ABTS, DPPH), ORAC assay and CAA test (cellular antioxidant activity)), the ability to inhibit growth of human colon cancer cells (HT29; determined using MTT assay), and the ability of studied compounds to protect DNA from oxidative damage (comet assay). Based on the obtained results, the relationship between the structure of studied anthocyanidins and their biological activity was assessed. The obtained results revealed that the number and position of the hydroxyl and methoxy groups in the anthocyanidin structure strongly influenced not only the color of anthocyanidins but most of all their antioxidant and biological activities.

Membrane permeabilizers enhance biofortification of Brassica microgreens by interspecific transfer of metabolites from tea (Camellia sinensis)

Interspecific metabolite transfer (ISMT) is a novel approach for plants biofortification. In this study, the effect of tea (Camellia sinensis; Cs), with or without membrane permeabilizers EDTA and Tween, as a donor plant on broccoli, cauliflower and kale sprouts was investigated. As a result, caffeine- and catechin-enriched broccoli, cauliflower and kale microgreens were produced. Kale sprouts were most permeable for catechins from Cs, while cauliflower was most permeable for caffeine. Cs + EDTA significantly increased vitamin C in broccoli and kale. Among the tested enzymes activity, pancreatic lipase was the most affected by the treatment with broccoli and cauliflower biofortified with Cs or Cs combined with permeabilizers. Broccoli sprouts biofortified with Cs most significantly inhibited α-amylase, while those biofortified with Cs combined with permeabilizers most significantly inhibited α-glucosidase. Results point to ISMT combined with membrane permeabilizers as a promising and eco-friendly biofortification strategy to improve the biopotential of Brassica microgreens.

Anti-cancer effect of Rumex obtusifolius in combination with arginase/nitric oxide synthase inhibitors via downregulation of oxidative stress, inflammation, and polyamine synthesis

Cancer continues to be a leading cause of death worldwide, making the development of new treatment methods crucial in the fight against it. With cancer incidence rates increasing worldwide, ongoing research must focus on identifying new and effective ways to prevent and treat the disease. The combination of herbal extracts with chemotherapeutic agents has gained much interest as a novel strategy to combat cancer. Rumex obtusifolius L. is a wild plant known for its medicinal properties and is widely distributed worldwide. Our preclinical evaluations suggested that R. obtusifolius seed extracts possessed cancer-inhibiting properties and we also evaluated the beneficial effects of the arginase inhibitor NG-hydroxy-nor-L-arginine and nitric oxide inhibitor NG-nitro-L-arginine methyl ester in the treatment of breast cancer. The current study aimed to combine these observations and evaluate the antioxidant and antitumor properties of R. obtusifolius extracts alone and in combination with the arginase and nitric oxide synthase inhibitors. Metabolic characterization of the plant extract using a liquid chromatography/high-resolution mass spectrometry advanced system revealed the presence of 240 phenolic compounds many of which possess anticancer properties, according to the literature. In vitro studies revealed a significant cytotoxic effect of the R. obtusifolius extracts on the human colon (HT29) and breast cancer (MCF-7) cell lines. Thus, a new treatment approach of combining R. obtusifolius bioactive phytochemicals with the arginase and nitric oxide synthase inhibitors NG-nitro-L-arginine methyl ester and/or NG-hydroxy-nor-L-arginine, respectively, was proposed and could potentially be an effective way to treat breast cancer. Indeed, these combinations showed immunostimulatory, antiproliferative, antioxidant, anti-inflammatory, and antiangiogenic properties in a rat breast cancer model.

Amelioration of the physio-biochemical responses to salinity stress and computing the primary germination index components in cauliflower on seed priming

The significant horticultural crop, cauliflower (Brassica oleracea L. var. botrytis) is vulnerable to the excessive salt concentration in the soil, which contributes to its scaled-down growth and productivity, among other indices. The current study examines the efficacy of hydropriming, halopriming, and osmopriming on the physio-biochemical attributes and tolerance to salinity (100 mM NaCl) in cauliflower under controlled conditions. The results showed that the salinity (100 mM NaCl) has significant deleterious impacts on cauliflower seed germination, seedling growth, and photosynthetic attributes, and provoked the production of reactive oxygen species. In contrast, different priming approaches proved beneficial in mitigating the negative effects of salinity and boosted the germination, vigor indices, seedling growth, and physio-biochemical attributes like photosynthetic pigments, protein, and proline content while suppressing oxidative damage and MDA content in cauliflower seedlings in treatment- and dose-dependent manner. PCA revealed 61% (PC1) and 15% (PC2) of the total variance with substantial positive relationships and high loading conditions on all germination attributes on PC1 with greater PC1 scores for PEG treatments showing the increased germination indices in PEG-treated seeds among all the priming treatments tested. All 13 distinct priming treatments tried clustered into three groups as per Ward's approach of systematic categorization, clustering the third group showing relatively poor germination performances. Most germination traits exhibited statistically significant associations at the p < 0.01 level. Overall, the results established the usefulness of the different priming approaches facilitating better germination, survival, and resistance against salinity in the cauliflower to be used further before sowing in the salt-affected agro-ecosystems.

Bioactive Compounds from Leaf Vegetables as Preservatives

Trends toward a healthier diet are increasing attention to clean-label products. This has led to the search for new ingredients that avoid the use of chemical additives. Food industries are responding to these demands by incorporating natural preservatives into their products, which consumers perceive as healthy. Leafy vegetables would fit this strategy since they are common components of the diet and are associated with beneficial health effects. The objective of this chapter is to offer an overview of the large number of bioactive compounds (phenolic acids, flavonoids, anthocyanins, glucosinolates, and sulfur compounds) present in these plants, which would be responsible for their activity as potential preservatives. Its incorporation into food would improve the quality and extend the shelf life by reducing oxidative processes and inhibiting or retarding the microbial growth that occurs during processing and storage without reducing the organoleptic characteristics of the product.

Glucosinolates and Polyphenols of Colored Cauliflower as Chemical Discriminants Based on Cooking Procedures

The impact of mild oven treatments (steaming or sous-vide) and boiling for 10 min, 25 min, or 40 min on health-promoting phytochemicals in orange and violet cauliflower (Brassica oleracea L. var. botrytis) was investigated. For this purpose, targeted ultra-high performance liquid chromatography–high-resolution mass spectrometry analysis of phenolics and glycosylates, combined with chemometrics, was employed. Regardless of cooking time, clear differentiation of cooked samples obtained using different procedures was achieved, thus demonstrating the distinct impact of cooking approaches on sample phytochemical profile (both, compound distribution and content). The main responsible components for the observed discrimination were derivatives of hydroxycinnamic acid and kaempferol, organic acids, indolic, and aromatic glucosinolates, with glucosativin that was found, for the first time, as a discriminant chemical descriptor in colored cauliflower submitted to steaming and sous-vide. The obtained findings also highlighted a strict relationship between the impact of the cooking technique used and the type of cauliflower. The boiling process significantly affected the phytochemicals in violet cauliflower whereas orange cauliflower boiled samples were grouped between raw and either steamed or sous-vide-cooked samples. Finally, the results confirm that the proposed methodology is capable of discriminating cauliflower samples based on their phytochemical profiles and identifying the cooking procedure able to preserve bioactive constituents.

Effects of Post-Harvest Elicitor Treatments with Ultrasound, UV- and Photosynthetic Active Radiation on Polyphenols, Glucosinolates and Antioxidant Activity in a Waste Fraction of White Cabbage (Brassica oleracea var. capitata)

Biosynthesis of phytochemicals in leaves of Brassica can be initiated by abiotic factors. The aim of the study was to investigate elicitor treatments to add value to waste of cabbage. A leaf waste fraction from industrial trimming of head cabbage was exposed to UV radiation (250-400 nm, 59 and 99 kJ∙m-2, respectively), photosynthetic active radiation (PAR, 400-700 nm, 497 kJ∙m-2), and ultrasound in water bath (35 kHz, at 15, 30 and 61 kJ∙l-1 water), in order to improve nutraceutical concentration. UV was more effective than PAR to increase the level of flavonols (2 to 3-fold higher) and hydroxycinnamate monosaccharides (1 to 10-fold higher). PAR was three times as effective as UV to increase anthocyanins. Interaction of PAR + UV increased antioxidant activity (30%), the content of five phenolics (1.4 to 10-fold higher), and hydroxycinnamic monosaccharides (compared with PAR or UV alone). Indoles were reduced (40-52%) by UV, but the other glucosinolates (GLS) were unaffected. Ultrasound did not influence any parameters. The results are important for white cabbage by-products by demonstrating that UV + PAR can be successfully used as an effectual tool to increase important phenolics and antioxidant activity of waste fraction leaves without an adverse effect on the main GLS.

A novel colorimetric indicator film based on watermelon peel pectin and anthocyanins from purple cabbage for monitoring mutton freshness

Novel films based on watermelon peel pectin (WMP) incorporated with purple cabbage extract (PCE) were developed for monitoring the freshness of mutton. The FTIR result showed that WMP and PCE interacted through hydrogen bonds. Low PCE content (≤1.5%) could be well dispersed in the film matrix, resulting in an enhancement in light transmittance, mechanical properties, barrier properties, and thermal stability. Excessive addition of PCE destroyed the compact structure of the film and decreased the comprehensive properties. The antioxidant and antimicrobial activity of WMP/PCE films were proportional to the amount of incorporated PCE. Moreover, the color of the film deepened as the PCE content increased. The film had excellent color stability and pH response properties. The WMP/PCE1.5 film color varied from mauve to baby blue according to the quality of mutton (fresh to spoiled). Our results suggested that the WMP/PCE film might have great potential for monitoring the freshness of mutton.

The comparison of cytotoxic and genotoxic activities of glucosinolates, isothiocyanates, and indoles

Chemopreventive properties of Brassica vegetables are attributed mainly to their characteristic compounds—glucosinolates (GLs) and their main hydrolysis products—isothiocyanates (ITCs) and indoles. In this study, we compared antiproliferative activity (MTT test in HT29 cells) and genotoxic effects (comet assay in HT29 cells and restriction analysis in a cell-free system) of three GLs (sinigrin (SIN), glucotropaeolin (GTL), and glucobrassicin (GLB)) with that of their major degradation products. Intact GLs did not exhibit cytotoxic activity, possibly due to their limited bioavailability. However, in the presence of myrosinase (MYR), GLs gained the ability to inhibit HT29 cells’ growth. The addition of MYR caused the hydrolysis of GLs to the corresponding ITCs or indoles, i.e. compounds that show stronger biological activity than parent GLs. Pure ITC/indole solutions showed the strongest antiproliferative activity. Based on the results of restriction analysis, it was found that GLs to a greater extent than ITCs caused DNA modification in a cell-free system. In the case of GLs, metabolic activation by the S9 fraction increased this effect, and at the same time changed the preferential binding site from the area of base pairs AT to GC base pairs. Of all compounds tested, only benzyl ITC caused DNA damage detectable in the comet assay, but it required relatively high concentrations.

Red and white cabbages: An updated comparative review of bioactives, extraction methods, processing practices, and health benefits

Red and white cabbages (Brassica oleracea var. capitata f. alba and rubra, respectively) are two of the most commercially valued vegetables in crucifers, well-recognized for their unique sensory and nutritive attributes in addition to a myriad of health-promoting benefits. The current review addressed the differential qualitative/quantitative phytochemical make-ups for the first time for better utilization as nutraceuticals and to identify potential uses based on the chemical makeup of both cultivars (cvs.). In addition, extraction methods are compared highlighting their advantages and/or limitations with regards to improving yield and stability of cabbage bioactives, especially glucosinolates. Besides, the review recapitulated detailed action mechanism and safety of cabbage bioactives, as well as processing technologies to further improve their effects are posed as future perspectives. White and red cabbage cvs. revealed different GLSs profile which affected by food processing, including enzymatic hydrolysis, thermal breakdown, and leaching. In addition, the red cultivar provides high quality pigment for industrial applications. Moreover, non-conventional modern extraction techniques showed promising techniques for the recovery of their bioactive constituents compared to solvent extraction. All these findings pose white and red cabbages as potential candidates for inclusion in nutraceuticals and/or to be commercialized as functional foods prepared in different culinary forms.

Cabbage (Brassica oleracea var. capitata): A food with functional properties aimed to type 2 diabetes prevention and management

Type 2 diabetes mellitus (T2DM) is increasing the prevalence worldwide at an alarming rate, becoming a serious public health problem that mainly affects developing countries. Functional food research is currently of great interest because it contributes to developing nutritional therapy strategies for T2DM prevention and treatment. Bioactive compounds identified in some plant foods contribute to human health by mechanisms of action that exert biological effects on metabolic pathways involved in the development of T2DM. Hence, vegetables with high bioactive compounds content may be a source of functional value for the control of T2DM. Cabbages varieties (Brassica oleracea var. capitata) such as green (GCB), white (WCB), and red (RCB) are foods consumed (raw or cooked) and cultivated in different regions of the world. Scientific evidence shows that cabbage has multi-target effects on glucose homeostatic regulation due to its high content of bioactive compounds. It has also been shown to decrease damage to organs affected by T2DM complications, such as the liver and kidney. Additionally, it could contribute as a preventive by attenuating problems underlying the development of T2DM as oxidative stress and obesity. This review highlights the functional properties of cabbage varieties involved in glucose regulation and the main mechanisms of the action exerted by their bioactive compounds. In conclusion, cabbage is a valuable food that can be employed as part of nutritional therapy or functional ingredient aimed at the prevention and treatment of T2DM.

Modeling Softening Kinetics at Cellular Scale and Phytochemicals Extractability in Cauliflower under Different Cooking Treatments

The effects induced by heat on Depurple and Cheddar (Brassica oleracea L. var. botrytis) during boiling, steaming, and sous-vide were investigated to elucidate the role of the basic cellular elements in softening and extractability of sterols and tocopherols. With this aim, an elastoplastic mechanical model was conceptualized at a cell scale-size and validated under creep experiments. The total amount of the phytochemicals was used to validate multivariate regression models in forecasting. Boiling was the most effective method to enhance the softening mechanisms causing tissue decompartmentalization through cell wall loosening with respect to those causing cell separation, having no impact on the phytochemical extractability. Sous-vide showed the lowest impact on cell wall integrity, but the highest in terms of cell separation. Steaming showed an intermediate behavior. Tissue of the Depurple cauliflower was the most resistant to the heat, irrespectively to the heating technology. Local heterogeneity in the cell wall and cell membrane, expected as a plant variety-dependent functional property, was proposed as a possible explanation because sterol extractability under lower heat-transfer efficiency, i.e., steaming and sous-vide, decreased in Depurple and increased in Cheddar as well as because the extractability of sterols and tocopherols was greater in Cheddar.

Separation and Determination of Chemopreventive Phytochemicals of Flavonoids from Brassicaceae Plants

The main aim of this study was to develop a method for the isolation and determination of polyphenols-in particular, flavonoids present in various morphological parts of plants belonging to the cabbage family (Brassicaceae). Therefore, a procedure consisting of maceration, acid hydrolysis and measurement of the total antioxidant capacity of plant extracts (using DPPH assay) was conducted. Qualitative analysis was performed employing thin-layer chromatography (TLC), which was presented to be a suitable methodology for the separation and determination of chemopreventive phytochemicals from plants belonging to the cabbage family. The study involved the analysis of 25 vegetal samples, including radish, broccoli, Brussels sprouts, kale, canola, kohlrabi, cabbage, Chinese cabbage, red cabbage, pak choi and cauliflower. In addition, selected flavonoids content in free form and bonded to glycosides was determined by using an RP-UHPLC-ESI-MS/MS method.

Red cabbage anthocyanins: Stability, extraction, biological activities and applications in food systems

Red cabbage anthocyanins are of great interest as natural food colorants in the food industry; as they represent the color over a broad range of pH-values compared to anthocyanins from other natural sources. It is important to select an appropriate technique with high recovery of anthocyanins from red cabbage, among which extraction with organic solvents is the most applied extraction method. Currently, novel extraction techniques are employed as an alternative to the solvent extraction method, providing advantages such as higher anthocyanin recovery in a shorter time, lower solvent utilization, and minimum quality degradation. However, the incorporation of extracted anthocyanins into foodstuffs and pharmacological products is limited due to their low bioavailability and relative instability toward environmental adverse conditions, such as pH, temperature, enzymes, light, oxygen and ascorbic acid. In addition to increased structural stability of anthocyanins through glycosylation and acylation, their stability could be improved by copigmentation and encapsulation.

Interactions between polyphenolic antioxidants quercetin and naringenin dictate the distinctive redox-related chemical and biological behaviour of their mixtures

Food synergy concept is suggested to explain observations that isolated antioxidants are less bioactive than real foods containing them. However, mechanisms behind this discrepancy were hardly studied. Here, we demonstrate the profound impact of interactions between two common food flavonoids (individual: aglycones quercetin-Q and naringenin-N- or their glycosides rutin-R and naringin-N+ vs. mixed: QN- and RN+) on their electrochemical properties and redox-related bioactivities. N- and N+ seemed weak antioxidants individually, yet in both chemical and cellular tests (DPPH and CAA, respectively), they increased reducing activity of mixtures synergistically. In-depth measurements (differential pulse voltammetry) pointed to kinetics of oxidation reaction as decisive factor for antioxidant power. In cellular (HT29 cells) tests, the mixtures exhibited properties of a new substance rather than those of components. Pure flavonoids did not influence proliferation; mixtures stimulated cell growth. Individual flavonoids tended to decrease global DNA methylation with growing concentration; this effect was more pronounced for mixtures, but not concentration-dependent. In nutrigenomic studies, expression of gene set affected by QN- differed entirely from common genes modulated by individual components. These results question the current approach of predicting bioactivity of mixtures based on research with isolated antioxidants.

Potentiation of incretin hormones and modulation of metabolic enzymes as possible mechanisms behind the insulin sensitizing effects of cabbage-metformin treatment

In our study, we treated high fructose diet-induced insulin resistance in rats with any of metformin, cabbage (80%w/w) or combined metformin and cabbage (MetCabb), and observed the activities of glycolysis and gluconeogenesis regulatory enzymes, incretin hormones and other hormones affecting glucose homeostasis. Comparisons were made with normoglycemic noninsulin resistance rats (control) and insulin-resistant untreated rats (INres). Baseline analysis showing elevated fasting blood sugar (>250 mg/dl), insulin (>25 µIU/ml) and HOMA-IR (>10) satisfied the criteria for recruitment into the insulin-resistant groups. Treatment lasted for 12 weeks. HOMA-IR values significantly (P < 0.05) decreased from 24.7 to 5.5 and 10.6 respectively with MetCabb treatment. MetCabb normalized HOMA-IR values and mean β-cell responsiveness of the INres. Cabbage and metCabb normalized the leptin levels relative to control. The mean fasting blood sugar, insulin, and c-peptide levels with MetCabb treatment reverted to control levels. We found a strong positive linear correlation between the glucagon levels (r = 0.9145) and increasing HOMA-IR values while both incretin hormones; GLP-1 and GIP negatively regressed (r = -0.8084 and -0.8488). MetCab treatment produced comparable values of GLP-1 and GIP to the control. A strong positive correlation was found between the HOMA-IR values and the PEPCK (r = 0.9065), F-1,6-BPase (r = 0.7951), and G-6-Pase (r = 0.7893). The hexokinase (r = -0.807), PFK (r = -0.9151), and PK (r = -0.7448) levels regressed as HOMA-IR values increased. The glycolytic and gluconeogenic enzymes except PEPCK reverted to control levels with MetCabb treatment. Combination of metformin and cabbage was more effective than individual treatments.

Phytotherapy and food applications from Brassica genus

Plants of the genus Brassica occupy the top place among vegetables in the world. This genus, which contains a group of six related species of a global economic significance, three of which are diploid: Brassica nigra (L.) K. Koch, Brassica oleracea L., and Brassica rapa L. and three are amphidiploid species: Brassica carinata A. Braun, Brassica juncea (L.) Czern., and Brassica napus L. These varieties are divided into oily, fodder, spice, and vegetable based on their morphological structure, chemical composition, and usefulness of plant organs. The present review provides information about habitat, phytochemical composition, and the bioactive potential of Brassica plants, mainly antioxidant, antimicrobial, anticancer activities, and clinical studies in human. Brassica vegetables are of great economic importance around the world. At present, Brassica plants are grown together with cereals and form the basis of global food supplies. They are distinguished by high nutritional properties from other vegetable plants, such as low fat and protein content and high value of vitamins, fibers along with minerals. In addition, they possess several phenolic compounds and have a unique type of compounds namely glucosinolates that differentiate these crops from other vegetables. These compounds are also responsible for numerous biological activities to the genus Brassica as described in this review.

Impact of Mild Oven Cooking Treatments on Carotenoids and Tocopherols of Cheddar and Depurple Cauliflower (Brassica oleracea L. var. botrytis)

The effect of steam and sous-vide oven procedures on liposoluble antioxidants of colored cauliflower (orange and purple) was assessed for the first time and compared with domestic practice (boiling). In raw samples, the total carotenoid content was 10-fold higher in Cheddar than in Depurple (20.9 ± 2.1 vs. 2.3 ± 0.5 mg/kg dry weight), whereas the level of tocopherols was similar (28.5 ± 4.4 vs. 33 ± 5.2 mg/kg dry weight). The Cheddar liposoluble antioxidant matter contained violaxanthin, neoxanthin, α-carotene and δ-tocopherol, not detected in Depurple. All tests increased the bioactive compounds extractability with steam oven and sous-vide displaying similar effects, lower than boiling. In boiled Cheddar cauliflower, the total carotenoids and tocopherols contents increased with cooking time until they were 13-fold and 6-fold more than in raw cauliflower, respectively. Conversely, in the Depurple variety, contents increased by half with respect to the orange variety. However, from a nutritional point of view, no differences were revealed among the three different cooking treatments in terms of vitamin A and E levels expressed in μg/100 g of fresh vegetable because of the higher water content of boiled samples that must be considered when evaluating the effect of thermal treatment on cauliflower nutritional traits.

Comparative study of young shoots and the mature red headed cabbage as antioxidant food resources with antiproliferative effect on prostate cancer cells

The increasing knowledge on health benefit properties of plant origin food ingredients supports recommendations for the use of edible plants in the prevention of diet related diseases, including cancer. The beneficial effects of young shoots of red cabbage can be attributed to their mixture of phytochemicals possessing antioxidant and potential anticancer activity. The objective of this study was to compare the content of bioactive compounds, including HPLC analysis of polyphenols and antioxidant activity of young shoots of red cabbage and the vegetable at full maturity. The content of vitamin C and polyphenols in juices obtained from young shoots and the mature vegetable were also determined. The other aim of this study was to confirm the hypothesis that juice of young shoots more effectively, compared to juice of the mature vegetable, reduces the proliferation of prostate cancer cell lines DU145 and LNCaP in vitro. A significantly higher content of vitamin C and carotenoids, as well as a higher antioxidant activity were found in edible young shoots in comparison to the mature vegetable. In addition, studies have shown higher amount of vitamin C in the juice of young shoots than in the juice of the mature vegetable and similar content of polyphenolic compounds. The level of total polyphenol content in the studied plant samples did not differ significantly. Flavonoids were the main polyphenols in young shoots and juice obtained from them, while phenolic acids were dominant in the mature vegetable and in juice obtained from it. The juice of young shoots has shown stronger in vitro anti-proliferation effect against prostate cancer cells than juice of the mature vegetable.

Young shoots of red cabbage could be a good source of phytochemicals with potential anticancer activity.

Colon Bioaccessibility under In Vitro Gastrointestinal Digestion of a Red Cabbage Extract Chemically Profiled through UHPLC-Q-Orbitrap HRMS

Red cabbage is a native vegetable of the Mediterranean region that represents one of the major sources of anthocyanins. The aim of this research is to evaluate the antioxidant capability and total polyphenol content (TPC) of a red cabbage extract and to compare acquired data with those from the same extract encapsulated in an acid-resistant capsule. The extract, which was qualitatively and quantitatively profiled by UHPLC-Q-Orbitrap HRMS analysis, contained a high content of anthocyanins and phenolic acids, whereas non-anthocyanin flavonoids were the less abundant compounds. An in vitro gastrointestinal digestion system was utilized to follow the extract's metabolism in humans and to evaluate its colon bioaccessibility. Data obtained showed that during gastrointestinal digestion, the total polyphenol content of the extract digested in the acid-resistant capsule in the Pronase E stage resulted in a higher concentration value compared to the extract digested without the capsule. Reasonably, these results could be attributed to the metabolization process by human colonic microflora and to the genesis of metabolites with greater bioactivity and more beneficial effects. The use of red cabbage extract encapsulated in an acid-resistant capsule could improve the polyphenols' bioaccessibility and be proposed as a red cabbage-based nutraceutical formulation for counteracting stress oxidative diseases.

Fruit, vegetables, and mushrooms for the preparation of extracts with α-amylase and α-glucosidase inhibition properties: A review

The inhibition of the α-amylase and α-glucosidase activity facilitates the maintenance of circulating glucose levels by decreasing the rate of blood sugar absorption. Existing enzyme inhibitors such as acarbose, miglitol, and voglibose are used for inhibiting the activity of these enzymes, however, alternative solutions are required to avoid the side-effects of using these drugs. The current study aims to review recent evidence regarding the in vitro α-amylase and α-glucosidase inhibition activities of extracts derived from selected fruit, vegetables, and mushrooms. The mechanisms of action of the extracts involved in the inhibition of both enzymes are also presented and discussed. Compounds including flavonoids, phenolic acids, anthocyanins, saponins, carotenoids, terpenes, sugars, proteins, capsaicinoids, fatty acids, alkaloids have been shown to have α-amylase and α-glucosidase inhibition activities. Harvesting period, maturity stage, sample preparation, extraction technique, and solvent type are parameters that affect the α-amylase and α-glucosidase inhibition activities of the extracts.

Grown to be Blue-Antioxidant Properties and Health Effects of Colored Vegetables. Part II: Leafy, Fruit, and Other Vegetables

The current trend for substituting synthetic compounds with natural ones in the design and production of functional and healthy foods has increased the research interest about natural colorants. Although coloring agents from plant origin are already used in the food and beverage industry, the market and consumer demands for novel and diverse food products are increasing and new plant sources are explored. Fresh vegetables are considered a good source of such compounds, especially when considering the great color diversity that exists among the various species or even the cultivars within the same species. In the present review we aim to present the most common species of colored vegetables, focusing on leafy and fruit vegetables, as well as on vegetables where other plant parts are commercially used, with special attention to blue color. The compounds that are responsible for the uncommon colors will be also presented and their beneficial health effects and antioxidant properties will be unraveled.

The Relationship between Phytochemical Composition and Biological Activities of Differently Pigmented Varieties of Berry Fruits; Comparison between Embedded in Food Matrix and Isolated Anthocyanins

The aim of this research was to correlate the composition of phenolic compounds and bioactivities (antioxidant, cytotoxic, antigenotoxic, and influence on selected enzymatic activities) exhibited by extracts from differently pigmented raspberry (yellow and red), grape (white and red), mulberry (white and black), and currant (white, red, and black) varieties. It was presumed that phytocomplexes of the same species will be similar while differing significantly only by the content of anthocyanins in colored varieties, which will impact biological properties. Additionally, to compare food matrix embedded and isolated anthocyanins, the influence of purified solution, in concentrations matching the total concentration of anthocyanins in appropriate colored plant samples, on investigated biological activities was studied. The phenolic compound composition and antioxidant profiles showed that anthocyanin content was correlated only with antioxidant capacity of tested plant extracts. The other determined biological activities failed to reveal any simple relationship between chemopreventive potential and anthocyanin composition in fruits studied nor any similarity to biological properties of isolated cyanidin-3-O-glucoside. These observations indirectly support the food synergy concept, that points to interactions between different phytochemicals as a factor deciding about the final bioactivity of edible plants.

The Influence of Diet Interventions Using Whole, Plant Food on the Gut Microbiome: A Narrative Review

Dietary intake is a key determinant of gastrointestinal microbiota composition. Studies have considered the relationship between gut microbiota and dietary patterns. It is likely that certain plant foods that contain fiber and other bioactive matter may be more likely to drive microbial changes than others; however, study design and other factors can make interpretation of the literature difficult. Fifteen well-controlled, well-defined diet interventions published between 2008 and 2018 using whole, plant foods were evaluated for their influence on gut microbiota. There was limited effect on microbial diversity across studies and modest microbial changes were noted in 10 of 15 studies. More research is needed before specific plant foods can be recommended to improve gut microbiota and ultimately health. Methodologic considerations for future diet and microbiome studies are discussed. Additional research to better understand how specific whole, plant foods influence microbe composition, functionality, and metabolite production is needed, as are mechanistic studies linking diet-induced gut microbe changes to health.