Effects of Preparation Conditions on Antioxidant Potential of Some Herbal Teas (original) (raw)
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Fermentation, 2021
Ginger (Zingiber officinale R.), lemon (Citrus limon L.) and mint (Mentha sp.) are commonly consumed medicinal plants that have been of interest due to their health benefits and purported antioxidant capacities. This study was conducted on the premise that no previous study has been performed to elucidate the antioxidant and phenolic profile of the ginger, lemon and mint herbal tea infusion (GLMT). The aim of the study was to investigate and characterise the phenolic contents of ginger, lemon, mint and GLMT, as well as determine their antioxidant potential. Mint recorded the highest total phenolic content, TPC (14.35 ± 0.19 mg gallic acid equivalent/g) and 2,2′-azino-bis(3-e-thylbenzothiazoline-6-sulfonic acid), ABTS (24.25 ± 2.18 mg ascorbic acid equivalent/g) antioxidant activity. GLMT recorded the highest antioxidant activity in the reducing power assay, RPA (1.01 ± 0.04 mg ascorbic acid equivalent/g) and hydroxyl radical scavenging assay, •OH-RSA (0.77 ± 0.08 mg ascorbic acid eq...
Food Research International, 2006
The changes in the stability of antioxidant capacity with time and its relation to the phenolic content were evaluated in eight Indian herbal teas. These herbal teas are claimed to be antistress, immunomodulator, anti-aging, anti-inXammatory, appetizer, stimulant, blood puriWer, energizer, antidepressant, antidiabetic, rejuvenative, analgesic, antiviral, nervine, diuretic, antihypertensive and memory enhancer. Antioxidant capacity was determined over a period of 15 months from the date of their procurement using assays for SOD mimetic activity, LPO inhibitory capacity and total thiol content, which decreased positively with time. Total phenolic content was determined spectrometrically according to the Folin-Ciocalteu method and calculated as gallic acid equivalents (GAE). Herbal teas with higher phenolic content showed a comparatively less decline in antioxidant capacity. The SOD mimetic activity values in control samples (at the time of procurement) were seen to be in the range of 54.63-93.64 units/min/mg of extract which after 15 months of storage decreased upto 7.4-folds in some samples. LPO inhibitory capacity was observed upto 96.75% in herbal tea E at the time of procurement which dropped to 63.85% inhibition of MDA formation/5 l of extract after 15 months. In case of total thiol, the values were seen in the range of 0.55-1.71 mg/g and after 15 months it was from 0.12 to 0.21 mg/g. In all these cases high antioxidant activity was seen in the samples with higher phenolic content which also showed comparatively less decline in antioxidant capacity after considerable storage time. The results have signiWcance, as most of the herbal teas available in the local markets in India do not carry any information regarding the period of use without decline in its beneWcial eVects.
Phytotherapy Research, 2010
Herbal infusions and decoctions in water are some of the most commonly consumed beverages in the world. Although water is not a good solvent for many of the active components in herbs, liquid preparations are rich in several bioactive compounds. Most of them have powerful antioxidant activity and have been related to medicinal herbs' properties. Herein, decoctions and infusions in water of lemon-verbena (Aloysia citrodora) aerial parts and leaves, fennel (Foeniculum vulgare), pennyroyal (Mentha pulegium) and spearmint (Mentha spicata) aerial parts with different periods of storage (0, 30, 60 and 120 days), were prepared. The effects of the method of preparation and storage period in their antioxidant properties were analysed. For all the analysed species, infusions gave better results than the corresponding decoctions. Spearmint infusions showed the highest antioxidant properties, at all the storage periods, probably due to the highest levels and synergy between phenolics, flavonoids and ascorbic acid found in this sample. Linear discriminant analysis confirmed that the length of storage period has a significant influence in antioxidant activity and antioxidants content. Flavonoids and reducing sugars proved to be the parameters that most highly contribute to cluster individual groups according to different periods of storage.
A Comparison of Selected Phytochemical and Antioxidant Potential of Two Tea Beverages
Food and Nutrition Sciences, 2017
Herbal teas have been used as medicinal aids for centuries to treat a myriad of illnesses and have also been suggested to function in chemoprevention. Having numerous phytochemicals, the purported health benefits of herbal teas may be due to their antioxidant potential. Herbal tea blends infused with spices are increasing in popularity in U.S., and preliminary studies suggest the synergistic effects of combining herbal teas and spices. Some teas that are increasing in popularity include raspberry leaf, strawberry leaf, and hibiscus. The objectives of this study were to determine the antioxidant capacity of tea beverages (herbal (HT) (functional yogurt-based beverage-new product) and Chai (CT) (store bought) and to determine consumer preferences of tea beverages (HT and CT). Total phenolic content (TPC), total flavonoid content (TFC), free radical scavenging activity by 1,1-diphenyl-2-picryhydrazyl (DPPH), trolox equivalent antioxidant capacity (TEAC) and ferric reducing antioxidant power (FRAP) were evaluated in methanolic and aqueous beverage extracts. A functional yogurt-based beverage (HT) was developed and sensory analysis was also conducted using a 5-point hedonic scale comparing consumer preference of HT or CT beverages. The highest phenolic content was observed in CT aqueous extracts (AQ) (500 mg GAE/g), all other extracts had significantly (P ≤ 0.05) lower phenolic content. CTAQ had significantly (P ≤ 0.05) higher flavonoid content compared to all other extracts (1.7 mg CAE/g). The highest DPPH radical scavenging activity was observed in HT methanolic extracts (ME) (44.48% inhibition). The lowest DPPH radical scavenging was observed in HTAQ (21.88% inhibition). Approximately 61% of sensory panelists gave the yogurt-based developed product a rank of 4 or greater (on a 5-point hedonic scale) with 41% of panelists preferring the HT beverage over CT beverage. The results of this study suggest that a combination of herbal teas and spices may benefit consumers by improving their antioxidant status and may have potential as a functional-beverage.
In vitro Antioxidant Activity and Polyphenolic Content of a Polyherbal Tea and Its Constituents
European journal of medicinal plants, 2015
In this study, the antioxidative effectiveness, and polyphenolic content of methanol and aqueous extracts of spices such as Lippia adoensis (Koseret), Nigella sativa (Thikur azmud), Piper capense (Timiz), Thymus schimperi (Tosign) and Trachyspermum ammi (Netchazmud), consumed among people of Ethiopia were investigated. Methods: The antioxidant activity was assessed via established in vitro assay models such as 2, 2-Diphenyl-1-Picrylhydrazyl (DPPH) radical quenching assay, reducing power assay and reactive nitrogen species (RNS) inhibitory potential. Total phenolics content was measured according to Folin-Ciocalteu's method and total flavonoid content was estimated by using Aluminium chloride colorimetric method. Results: The results showed that the total phenolic content was highest in both methanol (720 AE 0.04 mg GAE/100 g extract DW) and aqueous (580 AE 0.08 mg GAE/100 g DW) extracts of L. adoensis. Among the five tested spices, the methanol and aqueous extracts of L. adoensis exerted the strongest DPPH radical quenching activity with IC 50 values of 49.17 AE 1.26 and 20.99 AE 8.6 μg/mL, respectively. Both methanol and aqueous extracts of L. adoensis showed notable reducing capacity. The highest RNS scavenging activity was shown by both methanol (IC 50 597.21 AE 6.99 μg/mL) and aqueous (IC 50 ¼ 551.5 AE 28.9 μg/mL) extracts of L. adoensis. High to moderate positive correlations were observed between total phenolic contents and in vitro antioxidant assays. This indicates that the antioxidant activities of the tested spices are attributed to the phenolic contents. Conclusion: The results of the present work revealed that the tested spices demonstrated high phenolic contents and antioxidant properties. Thus, these spices are worth considering as important sources of natural antioxidant agents.
Antioxidant scavenging potential of South African export herbal teas
South African Journal of Botany, 2004
The flavonoid content as well as the superoxide anion and hydroxyl radical scavenging activities of water extracts of rooibos (Aspalathus linearis (Burm. f.) R. Dahlgr.), honeybush (Cyclopia intermedia E. Mey.) and roselle (Hibiscus sabdariffa L.), three South African herbal teas which are commercial products exported world-wide, were investigated. The results indicated that the water extracts of rooibos exhibited the best scavenging activity for both the hydroxyl radical and superoxide anion followed by honeybush and then roselle. This seems to be due to the total flavonoid concentration, which was the highest in rooibos and lowest in roselle.
Tea and herbal infusions: Their antioxidant activity and phenolic profile
Food Chemistry, 2005
Tea and herbal infusions have been studied for their polyphenolic content, antioxidant activity and phenolic profile. The total phenolics recovered by ethyl acetate from the water extract, were determined by the Folin-Ciocalteu procedure and ranged from 88.1 ± 0.42 (Greek mountain tea) to 1216 ± 32.0 mg (Chinese green tea) GAE (Gallic acid equivalents)/cup. The antioxidant activity was evaluated by two methods, DPPH and chemiluminescence assays, using Trolox and quercetin as standards. The EC 50 of herbal extracts ranged from 0.151 ± 0.002 mg extract/mg DPPH (0.38 quercetin equivalents and 0.57 Trolox equivalents), for Chinese green tea, to 0.77 ± 0.012 mg extract/mg DPPH (0.08 quercetin equivalents and 0.13 Trolox equivalents), for Greek mountain tea. Chemiluminescence assay results showed that the IC 50 ranged from 0.17 ± 3.4 · 10 À3 lg extract/ml of the final solution in the measuring cell (1.89 quercetin and 5.89 Trolox equivalents) for Chinese green tea, to 1.10 ± 1.86 · 10 À2 g extract/ml of the final solution in the measuring cell (0.29 quercetin and 0.90 Trolox equivalents) for Greek mountain tea. The phenolic profile in the herbal infusions was investigated by LC-DAD-MS in the positive electrospray ionization (ESI þ ) mode. About 60 different flavonoids, phenolic acids and their derivatives have been identified.
2021
The purpose of this study was to investigate the antioxidant capacity of different tea plant: mint, linden, chamomile, St. John’s wort, green and black tea in relation to total phenolic content. The antioxidant capacity of the tea infusions at different brewing times was determined using DPPH assay while the total phenolic content (TPC) was assessed using the modified Folin-Ciocalteu method. The results showed that there were significant statistical differences in antioxidant capacity depending on infusion time, according to one-way ANOVA analysis. Leaves used as components of tea infusions were analyzed by FAAS for their content of iron and copper in the dry product and in the infusion. The correlation between TPC and DPPH capacity of tea plant infusions was evaluated by Pearson correlation matrix. Total phenolics compounds content was positively and significantly correlated with DPPH capacity for all infusions time. Significant correlation was observed between TPC and the copper c...
The methanolic crude extracts of some commonly used medicinal plants were screened for their free radical scavenging properties using ascorbic acid as standard antioxidant. Free radical scavenging activity was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. The overall antioxidant activity of green tea Camellia sinensis, was the strongest, followed in descending order by Thyme (Thymus vulgaris L.) (Salvia officinalis L.) Showed less free radical scavenging activity with the DPPH method. All the methanolic extracts exhibited antioxidant activity significantly. The IC 50 of the methanolic extracts ranged between 7.4 ± 0.1 and 14.9 ± 0.2 µg/ml and that of ascorbic acid was 9.8 ± 1 µg/ml. The study reveals that the consumption of these spices would exert several beneficial effects by virtue of their antioxidant activity.
2008
Tea is a powerful antioxidant beverage consumed in many soft drinks today. The characterization of its antioxidative properties during and especially after its preparation procedure, inclusive their long time stabilities, is an important tool for the soft drink industry. The antioxidative capacity and re- activity are two parameters which gives a compre- hensive description of the antioxidant properties. Both parameters are integrated in the antioxidative power AP, a 2D factor. The AP of the green tea bev- erage exceeds all other types of tea. Black tea has an AP which is six times lower than that of green tea.