Relation among taste-related compounds (phenolics and caffeine) and sensory profile of erva-mate (Ilex paraguariensis)

Erva-mate (Ilex paraguariensis St. Hil.) is a native species from temperate regions of South America, such as Brazil, Paraguay, and Argentina, that is consumed as a beverage known as mate. The objective of this research was to determine the content of caffeic acid, catechin, chlorogenic acid, caffeine, and gallic acid in mate to explain their influence in beverage taste and sensory differences between native and reforested plants, as well as between beverages from plants of different regions of Brazil (Santa Catarina and Rio Grande do Sul states). Compounds were determined by HPLC and results were related to a sensory evaluation performed by trained tasters. Tasters considered the beverage from reforested plants to be more bitter than the beverage from native plants. Beverages from reforested plants had significantly higher caffeic acid and lower catechin, chlorogenic acid, caffeine, and gallic acid content than native plants. Beverages from plants of Santa Catarina state had significantly higher catechin, caffeine, and gallic acid content than plants from Rio Grande do Sul state.     

Toxigenic microorganisms in medicinal plants used for ritual protection of infants

Plants used as a part of infant protective rituals in some countries of South Eastern Africa and which use has been associated to food poisoning episodes were submitted to a microbiological analysis to investigate potential microbiological hazards. This characterization led to the detection of a high load of moulds and aerobic spore-formers microorganisms. Isolates of Bacillus cereus and Bacillus thuringiensis were observed to contained different toxin-encoding genes, and the production of diarrheal enterotoxin was confirmed in some of them. The production of aflatoxin B₁ and cyclopiazonic acid by strains of Aspergillus flavus, and citrinin and penicillic acid by Penicillium citrinum was revealed by HPLC. The toxicity of these isolates was also showed by the Artemia salina lethality test. The results indicate the presence of microorganisms with toxigenic potential in plants used as folk medicine in South Eastern Africa. The traditional use of these preparations should be carefully reconsidered due to the microbiological risks associated with their ingestion.     

Determination of catechins in green tea infusions by reduced flow micellar electrokinetic chromatography

A sulfated-β-cyclodextrin (s-β-CD) modified reduced flow micellar electrokinetic chromatography (RF-MEKC) method was developed and validated for the determination of catechins in green tea. The optimal electrolyte consisted of 0.2% triethylamine, 50 mmol/L SDS and 0.8% s-β-CD (pH = 2.9), allowing baseline separation of five catechins in 4 min. The samples and standards were injected at 0.6 psi for 5 s under constant voltage of −30 kV. Sample preparation simply involved extraction of 2 g of tea with 200 mL water at 95 °C under constant stirring for 5 min. The method demonstrated excellent performance, with limits of detection (LOD) and quantification (LOQ) of 0.02–0.1 and 0.1–0.5 μg/mL, respectively, and recovery percentages of 94–101%. The method was applied to six samples of Brazilian green tea infusions. Epigallocatechin gallate (23.4–112.4 μg/mL) was the major component, followed by epigallocatechin (18.4–78.9 μg/mL), epicatechin gallate (5.6–29.6 μg/mL), epicatechin (4.6–14.5 μg/mL) and catechin (3.2–8.2 μg/mL).     

Rebaudioside A release from matrices used in a yerba maté infusion

The release rates of rebaudioside A from matrices prepared with an agglutinant and yerba maté powder are reported. These matrices were used to delay the release of rebaudioside A when added to yerba maté and consumed as an infusion. Three agglutinants (Arabic gum, tapioca starch and maltodextrin) were used at 5% and 10% concentrations in each matrix preparation. Experimental data of extraction rate were fitted to two models in order to describe the release of rebaudioside A with each extraction. The best results were obtained with a matrix containing 10% maltodextrin. Extraction rate of this matrix and the material currently used by industries (sweetened yerba maté twigs) were compared.     

Pharmacological evidences for the extracts and secondary metabolites from plants of the genus Hibiscus

The scientific basis for the statement that plants and their active constituents play an important role in the prevention of chronic and degenerative diseases is continuously advancing. In fact, the origin of many therapeutic substances is due to secondary metabolism in the plant. The genus Hibiscus contains 220 species distributed around the world. It is an interesting source of potential bioactive molecules, as phenolic compounds, triterpene derivatives, phytosteroids, with antioxidant, cardioprotective, antihypertensive and antiproliferative activities. This work reviews the pharmacological evidence of extracts of plants from the genus Hibiscus, giving an overview of the most studied biological effects and the known phytochemical composition. Although more studies are necessary, Hibiscus spp. exhibits proven potential to become of important pharmacological interest.     

Direct characterisation of phenolic antioxidants in infusions from four Mapuche medicinal plants by liquid chromatography with diode array detection (HPLC-DAD) and electrospray ionisation tandem mass spectrometry (HPLC-ESI-MS)

A simple, fast and direct method was developed for the qualitative analysis of phenolic constituents from infusions of Mapuche medicinal plants. Teas made of Linum chamissonis Schiede, Quinchamalium chilensis Mol., Adesmia emarginata Clos. and Escallonia illinita K. Presl. were analysed by high-performance liquid chromatography with diode array detector (HPLC-DAD) and electrospray mass spectrometry (ESI-MS). This technique allowed for the first time the tentative identification of 16 phenolic compounds in E. illinita, 27 in Q. chilensis, 10 in L. chamissonis and 19 in A. emarginata. The compounds were mainly phenolic acids, flavonoid glycosides, anthocyanins and tannins. The total phenolic and flavonoid content of the infusions was assessed as well as the free radical scavenging capacity measured by the bleaching of a solution of the 2,2-diphenyl-1-picrylhydrazyl (DPPH⁻) radical. From the four species, Q. chilensis exhibited the strongest antioxidant activity with highest total phenolic and flavonoid content.     

Concentration of biologically active compounds extracted from Ilex paraguariensis St. Hil. by nanofiltration

The aim of this study was to characterise the bioactive compounds in mate (Ilex paraguariensis St. Hil) extract and in concentrated mate extract obtained by nanofiltration (NF). Also, the impact of NF on the antioxidant activity of both mate extracts was evaluated in vitro and using eukaryotic cells of Saccharomyces cerevisiae (yeast assay). The results showed a significant increase in the contents of total phenolics (338%), chlorogenic acid (483%), theobromine (323%), caffeine (251%), chlorophyll (321%), condensed tannins (278%) and saponins (211%) in the concentrated mate extract. The concentrated mate extract showed higher in vitro antioxidant activity than the mate extract. According to the results obtained, it can be stated that the use of nanofiltration membrane is a valid approach for the concentration of biologically active compounds in aqueous extract of mate.     

Analysis of chlorogenic acids in beverages prepared from Chinese health foods and investigation, in vitro, of effects on glucose absorption in cultured Caco-2 cells

The effects of aqueous extracts of Kuding tea (Ilex latifolia Thunb.) and the large-leaf form of Camellia sinensis var. sinensis), chrysanthemum (Dendranthema morifolium Ramat), honeysuckle flower (Lonicera japonica Thunb.), and purple sweet potato (Ipomoea batatas) stem on glucose absorption were investigated using Caco-2 cells. Glucose absorption by Caco-2 cells was significantly inhibited by aqueous extract of Kuding tea, chrysanthemum and purple sweet potato stem under both Na⁺-dependent conditions and Na⁺-free conditions indicating effects on SGLT1 and GLUT transporters. Analysis of the (poly)phenols in these aqueous extracts suggested that dicaffeoylquinic acids and flavanols may be particularly important in producing these effects. Kuding tea extract was the most effective, suggesting that this merits evaluation in a clinical study.     

Study of the bioactive compounds variation during yerba mate (Ilex paraguariensis) processing

Ilex paraguariensis St. Hil. (Aquifoliaceae) (yerba mate) is one of the most used plant species in South America due to its nutritional and medicinal properties. The industrial processing involves different stages (green leaves, zapecado, drying, forced or natural aging) which can modify the qualitative and quantitative composition and the pharmacological activities. In this work, the main compounds, caffeoyl derivatives (caffeic acid, mono- and dicaffeoylquinic acids), methylxanthines (caffeine and theobromine) and flavonoids (rutin, quercetin and kaempferol) were studied by HPLC in extracts obtained by decoction of samples of a large amount of I. paraguariensis during its industrial process stages. The comparative quantitative analysis of all the samples indicated that those obtained after the zapecado, drying and aging stages possess higher content of biologically active principles when compared with green leaves. No differences were found between the natural and forced aging processes. This is the first complete report on the quantitative variation of the bioactive compounds of I. paraguariensis during each step of the industrial processing. The results obtained in this work provide a guideline for the obtention of extracts enriched in biological principles for the pharmaceutical, food and cosmeceutical industry.     

Short communication: Influence of pasteurization on the active compounds in medicinal plants to be used in dairy products

Interest from the dairy industry in adding herbal drugs to milk and yogurt products raises the question of whether these plant materials can be pasteurized. Root material of Rhodiola rosea, Eleutherococcus senticosus, and Panax ginseng, all plants with adaptogenic activities, was pasteurized. The content of active compounds in the root material before and after pasteurization was quantified by HPLC analysis. The results show that the eleutherosides in E. senticosus, and to an extent the ginsenosides from P. ginseng, could withstand pasteurization, whereas salidroside and rosavin from R. rosea did not survive pasteurization. Thus, R. rosea is not suitable for products requiring pasteurization.     

Intermittent drying simulation in a deep bed dryer of yerba maté

In the present research, the reduction of energy consumption was evaluated during drying of yerba maté branches when tempering periods were applied. An empirical model was validated describing the moisture variation with time and process temperature, using different operation conditions. This model was used to simulate an industrial dryer in order to minimize energy consumption, maintaining the final moisture content constant. Best results were obtained working in the following conditions: application of heat for 15 min, 15 min of tempering and continuous application of heat. The bed height (1 m) was reduced in 10% maintaining the dryer production increasing the belt velocity. Working with these conditions a 10% of energy consumption can be reduced.     

Phytochemical composition and in vitro antimicrobial and antioxidant activities of some medicinal plants

Different parts of three plants (Primula auriculata, Fumaria vaillantii and Falcaria vulgaris) were extracted with three different solvents to yield 72 crude extracts. The phytochemical analysis (chemical screening, GC–MS) of three plants was investigated for their antioxidant and antibacterial activity using nine Gram-positive and Gram-negative bacteria. The principal antioxidant and antimicrobial components were determined using HPLC with UV detection. All extracts possessed antibacterial activity especially methanolic extracts from flowers of P. auriculata. The DPPH-radical scavenging assay exhibited high antioxidant activities in three plants (more than 80% at 50 μg). The F. vulgaris showed high content of carvacrol (29.8%) as main component. The contents of carvacrol and fumaric acid in the methanolic–water extracts were 1119 and 1966 mg/l respectively. Our results indicate that these plants would be able to promise sources of natural products with potential antibacterial and antioxidant activity.     

Methylxanthines,phenolic composition,and antioxidant activity of bark from residues from mate tree harvesting (Ilex paraguariensis A. St. Hil.)

Leaves and products made from them are the major focus of research on bioactive compounds of mate (Ilex paraguariensis). However, studies on other parts of the plant, are scarce. The aim of this study was to determine the methylxanthines, phenolic compounds, and antioxidant activity of mate bark (residual biomass) and compare with those of mate leaves. The high antioxidant activity of mate bark and its high concentration of total polyphenols were apparent in both the aqueous and the methanolic extracts, the values of which were greater than those detected in the leaves. Of the phenolic acids identified, the levels of chlorogenic acid and 4,5-dicaffeoylquinic acid in the samples were significantly higher in the methanolic bark extract. With regard to methylxanthines, considerable concentrations were detected in the samples. The results obtained contribute to the viability of exploiting this residue, broadening the use of the mate plant.     

Antioxidant capacity and phenol content of selected Algerian medicinal plants

Extracts from the bark of Fraxinus angustifolia as well as the leaves of Pistacia lentiscus and Clematis flammula have been investigated for their reducing power, inhibition of linoleic acid peroxidation and scavenging capacity on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and H₂O₂ using in vitro spectrophotometric methods. The results indicate that the best overall antioxidant capacity was shown by extracts of Pistacia lentiscus, followed by Fraxinus angustifolia and Clematis flammula.     

Effect of the application of intermittent drying on Ilex paraguariensis quality and drying kinetics

The aim of this work was to study the effects of the application of tempering periods on the drying kinetics of yerba maté branches and on the resultant quality parameters of the finished product. Experiments were carried out in a convective pilot plant drier. Air temperature (60, 80 and 100 °C) and tempering time (0, 15 and 30 min) influenced the drying kinetics and the product quality (color parameters L and b, and the sugar and caffeine contents of an infusion prepared with the material). The influence of tempering time was higher at 60 °C than at the other temperatures. There were no differences between tempering times of 15 and 30 min. The Page model yielded a good fit to the experimental data, where the model parameter k varied with drying temperature.     

绿茶中药用绿原酸成分分析

本论文建立了以硅胶G60作为薄层固定相，层析分离（TLC）绿茶中绿原酸，使用紫外分光光度法（UV）定量分析绿茶中绿原酸含量的TLC－UV法。对绿茶中的绿原酸的提取条件、点样量及方法的精密度、准确度等进行了考察。并对绿茶（20010312粤春茶叶厂生产）中绿原酸含量进行了测定，测定结果显示每克绿花中含绿原酸9.12mg/g。     

Screening of some Algerian medicinal plants for the phenolic compounds and their antioxidant activity

Since recent times, there is a growing interest in the food industry and in preventive health care for the development and evaluation of natural antioxidants from medicinal plant materials. In the present work we have investigated the antioxidant potency of phenolic compounds of 11 indigenous wild plant species from the Algerian Atlas commonly used in Arab folk medicine for a wide range of conditions. The antioxidant activity of each phenolic extracts has been assessed by using the Trolox Equivalent Antioxidant Capacity (TEAC) as a chemical test, and in a dynamic way by a biological assay based on whole blood resistance to free radical aggression. Of the 11 tested plants, 2 showed prominent antioxidant activity: Anthemis arvensis and Artemisia campestris. These plants had a very high level of Trolox equivalents and induced a strong delay of free radical-induced red blood cells hemolysis compared to antioxidant references. Artemisia campestris was the best inhibitor, its effect was far stronger than that of caffeic acid and was more than three times as high as ascorbic acid and two times higher than α-tocopherol efficiency. HPLC analysis showed a good correlation between the antioxidant activity and hydroxycinnamic derivatives. These preliminary results on the in vitro protection of blood against oxidative stress emphasized the benefit of the phenolic compounds of these medicinal plants. Our results enable us to proceed towards more detailed chemical and pharmacological understanding of these plant materials and show the interest of natural antioxidant in medicinal plants for the prevention of much free radical-mediated pathology.     

Caffeoylquinic acids from leaves of Etlingera species (Zingiberaceae)

3-O-caffeoylquinic acid, 5-O-caffeoylquinic acid (chlorogenic acid), and 5-O-caffeoylquinic acid methyl ester, as elucidated by ¹H and ¹³C NMR, were isolated from leaves of Etlingera elatior. This is the first report of caffeoylquinic acids (CQA) including chlorogenic acid (CGA) in Zingiberaceae. Leaves of Etlingera species were rich in total phenols and CQA, and non-cytotoxic to normal human liver and African green monkey kidney cells. Content of CQA of E. elatior, Etlingera fulgens, and Etlingera rubrostriata leaves was significantly higher than leaves of Ipomoea batatas, and comparable to flowers of Lonicera japonica. CGA found only in leaves of E. elatior and E. fulgens was significantly higher in content than flowers of L. japonica, the commercial source.