Content of Selected Minerals and Active Ingredients in Teas Containing Yerba Mate and Rooibos

Assessing the stability of polyphenol content in red rooibos herbal tea using traditional methods and high-resolution mass spectrometry: Implications for studying dietary interventions in preclinical rodent studies

Preclinical rodent models are used to examine the relationship between tea consumption and bone health, where tea is available for rodents and typically replaced weekly. However, the extent to which the tea polyphenols change over time remains uncertain, despite its importance in preparing tea during preclinical rodent trials. Using an untargeted molecular approach, we applied a liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-QTOFMS) system to assess the molecular profile of red rooibos teas throughout a 6-day aging period. We found a significant, 3-fold decrease of polyphenols involved in bone metabolism, including m-coumaric acid, catechin derivatives and courmaroyl tartaric acid over 6 days, likely due to photochemical decomposition and autooxidation within tea extracts. Using a novel untargeted workflow for polyphenol characterization, our findings revealed the complexity of polyphenols in red rooibos teas that can inform the evidence-based decisions of how often to change teas during in vivo rodent trials.

Increased Osteoblastic and Osteocytic in Vitro Cell Viability by Yerba Mate (Ilex paraguariensis)

BACKGROUND

Yerba mate (YM, Ilex paraguariensis) consumption beneficially affects the bones. However, whether YM components exert their effect on bone cells directly remains elusive.

METHODS

We evaluated how main YM components affect osteoblastic (MC3T3-E1) and osteocytic (MLO-Y4) cells in vitro when administered separately or in an aqueous extract. MC3T3-E1 and MLO-Y4 cells were exposed to three different experimental conditions: (1) Caffeine, chlorogenic acid, and their combinations; (2) Caffeine, rutin, and their combinations; (3) Aqueous YM extract.

RESULTS

All polyphenol and caffeine concentrations as well as that of their tested combinations significantly increased MC3T3-E1 cell viability from 16.6% to 34.8% compared to the control. In MLO-Y4 cells, the lowest rutin and the two highest caffeine concentrations significantly increased cell viability by 11.9, 14.9, and 13.7%, respectively. While rutin and caffeine combinations tended to increase MLO-Y4 cell viability, different chlorogenic acid and caffeine combinations did not affect it. Finally, the aqueous YM extract significantly increased MLO-Y4, MC3T3-E1, and differentiated MC3T3-E1 cell viability compared to the control without treatment.

CONCLUSIONS

YM components (rutin, chlorogenic acid, and caffeine) positively affected bone cells, mainly pre-osteoblast cells. Moreover, the aqueous YM extract significantly increased MLO-Y4, MC3T3-E1, and differentiated MC3T3-E1 cell viabilities indicating an additional relevant nutritional property of YM infusion. Further studies would be required to elucidate the underlying effector mechanism of YM on the bones and its relationship with previously described in vivo positive effects.

Assessment on Solubility and Solid Phase Chemical Fractionation of Manganese in Hot Infusions of Green and Roasted Mate

A solid phase chemical fractionation (SPCF) of the Mn in hot infusions prepared from commercial samples of roasted (RM) and green mate (GM) using a chelating resin Chelex 100 (NH4+ form) was performed to assess the relative lability of this essential trace element (ETE). In addition, total Mn contents in the RM and GM samples and their infusions were determined by flame atomic absorption spectrometry. Total polyphenol (TP) contents and the presence of soluble melanoidins (SM) were correlated with the Mn solubility in the RM and GM infusions. From the SPCF study, it was possible to observe that the soluble Mn forms in the mate infusions were essentially associated with relatively noninert chemical species (98.4-99.7%), suggesting that they may be potentially bioavailable. In addition, the soluble Mn contents in the GM infusions were 20.5% higher than those found in the RM. Mn solubility in the (RM) infusions was highly and directly correlated (r = 0.99) with the soluble TP, while in the GM infusions, it was high and inversely correlated with soluble TP (r =  -0.87). On the other hand, Mn solubility in the RM and GM infusions was weakly correlated with the SM. It should be stressed that GM infusions can contribute with 57 and 44% more than the RM infusions to the recommended adequate intake of Mn established for females and males, respectively. Moreover, this work is the first to evaluate and compare the relative lability of Mn and its solubility in the RM and GM infusions.

Reaction kinetics of aspalathin degradation and flavanone isomer formation in aqueous model solutions: Effect of temperature, pH and metal chelators

The poor stability of aspalathin in aqueous solutions is a major challenge in delivering a shelf-stable ready-to-drink (RTD) green rooibos iced tea. The kinetics of aspalathin degradation and the formation of eriodictyol glucoside isomers [(S/R)-6-β-D-glucopyranosyleriodictyol and (S/R)-8-β-D-glucopyranosyleriodictyol] in aqueous buffers were modeled to understand and predict aspalathin losses during heat processing. The effects of temperature and pH on the rate constants of aspalathin degradation and eriodictyol glucoside isomer formation were determined in a 0.1 M phosphate buffer with 5.7 mM citric acid. The zero-order model best described the reaction kinetics of aspalathin degradation and eriodictyol glucoside isomer formation. Increasing the temperature and pH increased the reaction rate constants. The activation energies of the reactions were much lower at pH 6 than at pH 4, indicating that pH affected the temperature dependence of the reactions. The 8-C-glucosyl eriodictyol derivatives (RE8G and SE8G) formed at much lower rates than the 6-C-glucosyl eriodictyol derivatives (RE6G and SE6G). The metal chelators, citric acid, citrate and EDTA, drastically reduced the reaction rate constants, indicating the catalytic role of metal ions in aspalathin autoxidation. The results of the study could assist manufacturers to improve the shelf life of rooibos RTD beverages by changing the formulation and adjusting heat processing conditions.

Solubility of Cd, Cr, Cu, Ni, and Pb and Its Correlation with Total Polyphenols and Soluble Melanoidins in Hot Infusions of Green and Roasted Mate

The total and soluble contents of three potentially toxic elements (PTEs) (Cd, Cr, and Pb) and two essential elements (Cu and Ni) in commercial green and roasted mate (Ilex paraguariensis St. Hil.) and their hot infusions were accessed by inductively coupled plasma mass spectrometry. Total polyphenolic (TP) contents in the infusions were accessed by Folin-Ciocalteu method, and the presence of soluble melanoidins (SM) was evaluated by measuring absorbances at 420 nm. The soluble element contents in hot infusions of green mate were present in the following increasing order: Pb < Cd < Cr < Cu, and Ni. For hot infusions of roasted mate, the increasing order was: Cu < Pb < Cd < Cr < Ni. Except for Cr, hot infusions of roasted mate supply lower contents of the soluble PTEs than hot infusions of green mate. Cadmium was the only of evaluated trace element found in hot infusions of green and roasted mate as well as in some of their mate samples above the maximum allowed contents established by Brazilian legislation. Despite this, polyphenol and melanoidin contents in green and roasted mate infusions may reduce Cd bioavailability. The soluble trace elements that correlated directly with total polyphenols in hot infusions of green or roasted mate are indirectly correlated with the presence of soluble melanoidins. Moreover, this is the first study to evaluate the correlations of soluble forms of Cd, Cr, Cu, Ni, and Pb with the presence of SM and TP contents in hot infusions of green and roasted mate.

Ilex paraguariensis (A. St.-Hil.) leaf infusion decreases iron absorption in patients with hereditary hemochromatosis: a randomized controlled crossover study

This study proposed to investigate the effect of Ilex paraguariensis infusion on the absorption of non-heme iron in hereditary hemochromatosis (HH) patients with the HFE genotype. A two-way randomized, controlled, crossover trial was conducted on patients, aged 29-69 years, undergoing maintenance therapy. Fourteen HFE-HH patients ingested a meal containing 11.4 mg iron and 200 mL either of water (control) or of Ilex paraguariensis leaf infusion. The beverages were offered in random order, at intervals separated by a washout period of 7 days. Active surveillance showed no adverse effects. Blood samples were drawn shortly before and 1, 2, 3, and 4 h after the meal for serum iron measurement. A significant reduction in the postprandial serum iron was observed for HH patients after intake of the Ilex paraguariensis infusion (area under the curve (AUC) expressed as mean ± SEM: 173.3 ± 44.7 μmol h^-1 L^-1) compared to water (1449.4 ± 241.5 μmol h^-1 L^-1) (p < 0.001). In summary, intake of Ilex paraguariensis leaf infusion significantly inhibited the absorption of iron in patients with HH and, therefore, should be considered as a potential adjuvant for iron overload control.

Contribution of Major Groups of Food Products to the Daily Intake of Selected Elements-Results from Analytical Determinations Supported by Chemometric Analysis

Food is a major source of minerals for humans. The main objective of this study was to determine the intake level of 10 essential macro- (Na, K, Ca, and Mg) and trace elements (Cu, Zn, Mn, Fe, Cr, and Se) with major food groups among young adults. Dietary intake of elements was evaluated using the 24-h dietary recall technique in combination with F-AASand ICP-OES methods. A very high intake of sodium and a very low intake of calcium, combined with inappropriate sodium/potassium ratio, may be harmful to the health of the population. Dietary intake of trace elements was within the range of reference values in the subjects, with cereals being the major source of a majority of those elements, while meat (38% for Na), vegetables (25% for K), and milk products (75% for Ca) were the main contributors to the daily dietary intake of macroelements. PCA revealed several visible trends in the datasetAmong men, the intake of Zn, Cr Na and K was significantly correlated with the consumption of meat and vegetables, whereas Mg, Se, Fe and Cu with cereals and water and beverages. Among women, the intake of Mg was significantly correlated with the consumption of meat and vegetables.

Assessment of the nutritional value of various teas infusions in terms of the macro- and trace elements content

BACKGROUND

Herbal teas are a good alternative to traditional green, black, red and white teas. Herbal teas infusions are also consumed for therapeutic purposes. Teas are the source of many valuable, biologically active compounds, including elements. Infusions drawn up from various teas may be one of the minerals sources in a daily diet. In the study, an attempt was made to assess infusions prepared from popular teas in terms of the content of elements in them.

METHODS

In the work, the amounts of elements such as Ca (calcium), Cr (chromium), Cu (copper), Fe (iron), K (potassium), Mg (magnesium), Mn (manganese), Na (sodium), Ni (nickel) and Zn (zinc) were determined in herbal teas infusions as well as yerba mate and rooibos by atomic absorption spectrometry method (AAS). Their participation in covering the daily nutrient requirements for particular elements was also estimated.

RESULTS

The average amount (mg/g) of elements that passed from 1 g of teas to their infusions was following: Ca - 5.73 ± 3.33, K - 18.14 ± 9.50, Mg - 1.79 ± 3.47, Na - 1.34 ± 0.85, and (μg/g) for: Cr - 0.14 ± 0.14, Cu - 2.56 ± 1.53, Fe - 18.45 ± 11.90, Mn - 64.20 ± 88.82, Ni - 0.49 ± 0.30 and Zn - 10.77 ± 13.89. Among the tested teas, the infusions of hibiscus, horsetail, nettle, rooibos and yerba mate contained the largest quantities of minerals. A significant positive correlation was determined between the pH value of infusion and Mg content, as well as some pairs of correlating elements (Ca-K, Ca-Mg, Cr-Mg, Cu-Zn and K-Mg) were found in the analyzed brews.

CONCLUSIONS

Generally, the infusions of herbal teas to a small extent cover the daily allowance for elements, however they are a valuable complementary source of them.

Assessment of Nutrient and Food Group Intakes across Sex, Physical Activity, and Body Mass Index in an Urban Brazilian Population

The burden of preventable diet-related diseases is significant and becoming worse. Thus, accurately assessing food intake is crucial to guide public health policies and actions. Using food dietary recalls, we evaluated usual dietary intake according to physical activity and nutritional status in an adult urban population from Brasília, Brazil. The usual nutrient and energy intakes distributions were estimated using the Iowa State University (ISU) method. Energy and nutrient intakes were stratified by gender, age group, body mass index (BMI), and physical activity (PA). The prevalence of inadequate intake was highest for vitamins E and D. Both men and women had excessive sodium intake. The percentage of intakes below daily serving recommendations for food groups were 96% for cereals, 74% for vegetables, and 87% for dairy products, whereas percentage of intakes above daily serving recommendations were 97% for meat, 93% for pulses, and 99% for fat/oils. Energy and nutrient intakes were highest in overweight and physically active individuals within the categories of BMI and physical activity, respectively. Our study found that high-income urban Brazilians consume large quantities of meat, beans, fat/oils, and exhibit a low prevalence of nutrient inadequacies but have excessive sodium intake. Energy and nutrient intakes are highest among men, as well as overweight and physically active individuals.

Copper, Manganese, Zinc, and Cadmium in Tea Leaves of Different Types and Origin

Concentrations of selected metals (Cu, Mn, Zn, Cd) in tea leaves were investigated. Samples included black, green, and other (red, white, yellow, and oolong) teas. They were purchased on a local market but they covered different countries of origin. Beverages like yerba mate, rooibos, and fruit teas were also included in the discussion. Metal determinations were performed using atomic absorption spectrometry. In black teas, Mn/Cd ratio was found to be significantly higher (48,091 ± 35,436) vs. green (21,319 ± 16,396) or other teas (15,692 ± 8393), while Cd concentration was lower (31.4 ± 18.3 μg/kg) vs. other teas 67.0 (67.0 ± 24.4). Moreover, Zn/Cu and Cu/Cd ratios were, respectively, lower (1.1 ± 0.2 vs. 2.2 ± 0.5) and higher (1086 ± 978 vs. 261 ± 128) when comparing black teas with other teas. Intake of each metal from drinking tea was estimated based on the extraction levels reported by other authors. Contributions to recommended daily intake for Cu, Mn, and Zn were estimated based on the recommendations of international authorities. Except for manganese, tea is not a major dietary source of the studied elements. From the total number of 27 samples, three have shown exceeded cadmium level, according to local regulations.