The Impact of Domestic Cooking Methods on Myrosinase Stability, Glucosinolates and Their Hydrolysis Products in Different Cabbage (Brassica oleracea) Accessions

Glucoraphanin conversion into sulforaphane and related compounds by gut microbiota

Glucosinolate glucoraphanin, common in cruciferous vegetables, is a biologically stable precursor of isothiocyanates, such as sulforaphane and erucin, potent activators of Nrf2 signaling coordinating an adaptive response to oxidative stress. Sulforaphane is formed by the hydrolysis of glucoraphanin by a plant enzyme called myrosinase, which is inactivated in the stomach of mammals. Since the latter do not have enzymes possessing myrosinase-like activity, glucoraphanin can be metabolized by the gut microbiota, to sulforaphane, sulforaphane-nitrile, glucoerucin, erucin, and erucin-nitrile. Emerging evidence suggests that variations in gut microbiota composition significantly influence the efficiency and outcome of glucoraphanin metabolism, while sulforaphane itself may reciprocally modulate gut microbiota composition and functionality. This review examines the bidirectional interactions between glucoraphanin, sulforaphane, and gut microbiota. We assume that sulforaphane alleviates intestinal inflammation and oxidative stress maintaining intestinal homeostasis and gut barrier integrity. Besides, the role of sulforaphane in breaking the vicious cycle of oxidative stress and gut dysbiosis is reported, demonstrating the potential of dietary isothiocyanates to support gut barrier function.

The thermal degradation of glucomoringin and changes of phenolic compounds in moringa seed kernels during different degrees of roasting

The effect of heat treatment on the abundant bioactive compounds in moringa seed kernels (MSKs) during different degrees of roasting remains sparingly explored despite the flour of roasted MSKs has been incorporated into the human diet (e.g., cakes, cookies, and burgers) as a substitute to enrich the nutritional content. Therefore, we investigated the impacts of different roasting conditions (e.g., temperature and duration) on bioactive compounds (e.g., glucosinolates (GSLs), phenolic acids and alkaloids) and antioxidant capacity of MSKs. Our results showed that light and medium roasting increased the glucomoringin (GMG, the main GSL in MSKs) content from 43.7 (unroasted MSKs) to 69.7-127.3 μmol/g MSKs (dry weight), while excessive/dark roasting caused thermally-induced degradation of GMG (trace/undetectable level) in MSKs, resulting in the formation of various breakdown products (e.g., thiourea, nitrile, and amide). In addition, although roasting caused a significant reduction of some phenolic compounds (e.g., gallic, chlorogenic, p-coumaric acids, and trigonelline), other phenolic acids (e.g., caffeic and ferulic acids) and alkaloids (e.g., caffeine, theobromine, and theophylline) remarkably increased after roasting, which may contribute to the enhanced total phenolic content (up to 2.9-fold) and antioxidant capacity (up to 5.8-fold) of the roasted MSKs.

Fermenting kale (Brassica oleracea L.) enhances its functional food properties by increasing accessibility of key phytochemicals and reducing antinutritional factors

The properties of kale as a functional food are well established. We sought to determine how fermentation further enhances these properties. We tested different fermentation conditions: (i) spontaneous fermentation with naturally occurring bacteria, (ii) spontaneous fermentation with 2% salt, (iii) Lactococcus lactis, (iv) Lactobacillus acidophilus, (v) mixture of L. lactis and L. acidophilus, (vi) mixture of L. lactis, L. acidophilus, and Clostridium butyricum. We quantified selected bioactive components using high-performance liquid chromatography (HPLC) and antinutritional factors using a gravimetric method and spectrophotometry. We then determined (i) the antioxidant capacity of the vegetable, (ii) anti-inflammation capacity, and (iii) the surface microbiota composition by 16S sequencing. All fermentation methods imparted some benefits. However, fermentation with mixed culture of L. lactis and L. acidophilus was most effective in increasing polyphenols and sulforaphane accessibility, increasing antioxidant activity, and reducing antinutritional factors. Specifically, fermentation with L. lactis and L. acidophilus increased total polyphenols from 8.5 to 10.7 mgGAE/g (milligrams of gallium acid equivalent per gram) and sulforaphane from 960.8 to 1777 μg/g (microgram per gram) but decreased the antinutritional factors oxalate and tannin. Total oxalate was reduced by 49%, while tannin was reduced by 55%-65%. The antioxidant capacity was enhanced but not the anti-inflammation potential. Both unfermented and fermented kale protected equally against lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages and prevented increases in inducible nitric oxide synthase (iNOS), tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 messenger RNA (IL-6 mRNA) expression by 84.3%, 62%, 68%, and 85.5%, respectively. Unfermented and naturally fermented kale had high proportions of sulfur reducing Desulfubrio and Proteobacteria usually associated with inflammation. Fermenting with L. lactis and/or L. acidophilus changed the bacterial proportions, reducing the Proteobacteria while increasing the genera Lactobacilli and Lactococcus. In summary, fermentation enhances the well-known beneficial impacts of kale. Fermentation with mixed cultures of L. lactis and L. acidophilus imparts higher benefits compared to the single cultures or fermentation with native bacteria present in the vegetable.

Synergic Role of Dietary Bioactive Compounds in Breast Cancer Chemoprevention and Combination Therapies

Breast cancer is the most common tumor in women. Chemotherapy is the gold standard for cancer treatment; however, severe side effects and tumor resistance are the major obstacles to chemotherapy success. Numerous dietary components and phytochemicals have been found to inhibit the molecular and signaling pathways associated with different stages of breast cancer development. In particular, this review is focused on the antitumor effects of PUFAs, dietary enzymes, and glucosinolates against breast cancer. The major databases were consulted to search in vitro and preclinical studies; only those with solid scientific evidence and reporting protective effects on breast cancer treatment were included. A consistent number of studies highlighted that dietary components and phytochemicals can have remarkable therapeutic effects as single agents or in combination with other anticancer agents, administered at different concentrations and via different routes of administration. These provide a natural strategy for chemoprevention, reduce the risk of breast cancer recurrence, impair cell proliferation and viability, and induce apoptosis. Some of these bioactive compounds of dietary origin, however, show poor solubility and low bioavailability; hence, encapsulation in nanoformulations are promising tools able to increase clinical efficiency.

Degradation of glucosinolates and formation of isothiocyanates, nitriles, amines, and N,N'-dialk(en)yl thioureas during domestic boiling of red cabbage

Red cabbage is a popular vegetable in Central Europe and a rich source of glucosinolates (GLSs). Upon hydrolysis, GLSs form health-promoting isothiocyanates (ITCs), but also nitriles and epithionitriles. Recently, ITCs were shown to undergo further hydrolysis, yielding amines. Here, we analyzed the degradation of GLSs and the formation of ITCs, nitriles, epithionitriles, and amines during domestic-like cooking of red cabbage with addition of vinegar or baking soda. Both additives strongly affected the stability of GLSs and the formation of nitriles during boiling. Primary amines were found as a major degradation product of GLSs. In control and vinegar samples, formation of methylsulfinylalkyl amines increased during boiling. Additionally, for the first time, the formation of several N,N'-dialk(en)yl thioureas during boiling of Brassica vegetables was demonstrated, resulting from the reaction of GLS-derived ITCs and amines, and they were subsequently quantified. As references, five N,N'-dialk(en)yl thioureas were synthesized and characterized by NMR and HRMS.

In-silico studies of Brassica oleracea active compounds and their role in thyroid peroxidase activity

Cabbage, a leafy vegetable that is widely consumed across the globe, holds a significant place within the Brassica family. For almost a century, its potential anti-thyroid effects have captured attention. The presence of compounds such as thiocyanate and goitrin in cabbage has been extensively investigated for their ability to impede sodium-iodide symporter and thyroid peroxidase (TPO) activities. The present study is focused on uncovering the active constituents in cabbage that could interact with TPO, while also examining their stability under cooking temperatures. Employing molecular docking and molecular dynamic simulation techniques, we quantified the binding strength of phytochemicals present in cabbage with the target. Out of the 60 compounds identified in cabbage leaves, only 18 exhibited docking scores surpassing those of the commercially available anti-thyroid drug, methimazole. These chosen compounds were studied for binding free energy and pharmacokinetic properties. A specific compound, gamma-Terpinene, classified as a monoterpene, emerged as noteworthy due to its alignment with all criteria and the highest observed binding free energy compared to others. Furthermore, we explored the stability of gamma-Terpinene at 373.15K (cooking temperature) and observed its susceptibility to degradation. This might contribute to the relatively diminished anti-thyroid effects of cabbage when consumed in cooked form. Consequently, our findings suggest that the consumption of cooked cabbage could be more conducive to maintaining normal thyroid function, as opposed to its raw counterpart.Communicated by Ramaswamy H. Sarma.

Cooking Methods for Preserving Isothiocyanates and Reducing Goitrin in Brassica Vegetables

Glucosinolates in Brassica vegetables can be hydrolyzed into various products, e.g., chemopreventive agents, isothiocyanates (ITCs) and anti-thyroid substance, goitrin. Cooking can reduce goitrin but destroy isothiocyanates. This study aimed to optimize cooking conditions for reducing goitrin while preserving isothiocyanates in Brassica vegetables. Cabbage and Chinese kale samples were divided evenly into raw, blanched, steamed, and water-based stir-fried samples. Cooking temperature and time were varied at 60, 80, or 100 °C for 2, 4, or 6 min. The levels of goitrin, benzyl isothiocyanate (BITC), and sulforaphane (SFN) were measured using LC-MS/MS. Response surface model (RSM) was used to identify the optimal cooking conditions to reduce goitrin but preserve ITCs. Results showed that goitrin content in cabbage depended on the cooking methods, temperature, and time, while that of Chinese kale only depended on the methods. In contrast, the concentrations of SFN in cabbage and BITC in kale depended on the cooking temperature and time but not methods. Based on RSM analysis, the suggested household cooking methods for preserving isothiocyanates and reducing goitrin are steaming cabbage at 80-100 °C for 4 min and stir-frying Chinese kale at 60-100 °C for 2 min. Such methods may preserve the bioactive compounds while reducing food hazards.

3,3'-Diindolylmethane and indole-3-carbinol: potential therapeutic molecules for cancer chemoprevention and treatment via regulating cellular signaling pathways

Dietary compounds in cancer prevention have gained significant consideration as a viable method. Indole-3-carbinol (I3C) and 3,3'-diindolylmethane (DIM) are heterocyclic and bioactive chemicals found in cruciferous vegetables like broccoli, cauliflower, cabbage, and brussels sprouts. They are synthesized after glycolysis from the glucosinolate structure. Clinical and preclinical trials have evaluated the pharmacokinetic/pharmacodynamic, effectiveness, antioxidant, cancer-preventing (cervical dysplasia, prostate cancer, breast cancer), and anti-tumor activities of I3C and DIM involved with polyphenolic derivatives created in the digestion showing promising results. However, the exact mechanism by which they exert anti-cancer and apoptosis-inducing properties has yet to be entirely understood. Via this study, we update the existing knowledge of the state of anti-cancer investigation concerning I3C and DIM chemicals. We have also summarized; (i) the recent advancements in the use of I3C/DIM as therapeutic molecules since they represent potentially appealing anti-cancer agents, (ii) the available literature on the I3C and DIM characterization, and the challenges related to pharmacologic properties such as low solubility, and poor bioavailability, (iii) the synthesis and semi-synthetic derivatives, (iv) the mechanism of anti-tumor action in vitro/in vivo, (v) the action in cellular signaling pathways related to the regulation of apoptosis and anoikis as well as the cell cycle progression and cell proliferation such as peroxisome proliferator-activated receptor and PPARγ agonists; SR13668, Akt inhibitor, cyclins regulation, ER-dependent-independent pathways, and their current medical applications, to recognize research opportunities to potentially use these compounds instead chemotherapeutic synthetic drugs.

Consumer Liking of Turnip Cooked by Different Methods: The Influence of Sensory Profile and Consumer Bitter Taste Genotype

Brassica vegetables are bitter, predominantly because they contain bitter-tasting glucosinolates. Individuals with high bitter taste sensitivity are reported to have lower consumption of bitter vegetables. Studies reported that cooking methods can alter the sensory characteristics of vegetables, increasing acceptability. This study investigated consumer liking of turnip cooked by four methods (boiled-pureed, roasted, steamed-pureed and stir-fried) and related this to sensory characteristics. Additionally, this study examined the effect of the bitter taste genotype on taste perception and liking of the cooked turnip samples. Participants (n = 74) were recruited and the TAS2R38 genotype was measured. Liking, consumption intent, perception of bitterness and sweetness of turnip were evaluated. A sensory profile of the cooked turnip variants was also determined by a trained sensory panel. There were significant differences in the overall (p = 0.001) and taste (p = 0.002) liking between cooking methods. Turnip liking was increased when preparation led to sweeter taste profiles. The TAS2R38 genotype had a significant effect on bitter perception (p = 0.02) but did not significantly affect taste liking. In conclusion, the cooking method affected turnip liking, and the bitter perception in turnip was influenced by the TAS2R38 genotype. However, taste sensitivity did not predict turnip liking in this UK adult cohort.

Application of a salt substitute in bitter taste suppression and toward better acceptance of cruciferous vegetables in diet

The addition of table salt has been reported to enable better acceptance when consuming the least preferred vegetables belonging to the Cruciferae family. Considering the adverse effect of excessive table salt intake on incidence of hypertension and cardiovascular diseases, it is essential to explore an alternative healthier option for better acceptance and to encourage consumption of these vegetables. In this study, 261 adult participants were evaluated for their preferences toward basic tastes and food as well as sensory evaluation of a meal prepared from cruciferous vegetables with the addition of two different salts, sodium chloride and salt substitute containing a blend of potassium and sodium salts. A general questionnaire was used to assess taste and food preferences, while the Cruciferous Vegetable Food Frequency Questionnaire (CVFFQ) was used for vegetable intake assessment. The Labeled Magnitude Scale (LMS), Just About Right (JAR) scale, and several hedonic scales were used to determine taster status and sensory evaluation. The results show that a low concentration of the salt substitute did not impact bitterness suppression but did result in higher preference of the cruciferous vegetable meal. Although, subjects self-reported to have salty taste preferences were more sensitive to bitter taste, they did not perceive samples as less salty and less acceptable than subjects with lower sensitivity. The results show the necessity for further examination of the effectiveness of different concentrations of the assessed salt substitute in suppressing perceived bitterness of cruciferous vegetables and regarding their overall acceptance for inclusion in diets.

Advanced Research on Glucosinolates in Food Products

Glucosinolate-containing foods, such as vegetables from the plant order Brassicales and its derivative products, are valued for their health-beneficial properties [...].