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Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To study the difference in the contents of phenolics and the antioxidant activities between two kinds of Hawk tea of different maturity levels, and to evaluate their qualities, the contents of 15 phenolic compounds were determined using LC-MS/MS method. Then, the antioxidant activities of two types of tea were evaluated using DPPH radical scavenging rate, ABTS+ radical scavenging rate, and Fe3+ ferric reducing antioxidant power (FRAP). And then, the contents of 15 phenolic compounds and the antioxidant activities between two kinds of Hawk tea of different maturity levels were analyzed by analysis of variance (ANOVA). Based on the contents of 15 phenolic compounds, hierarchical cluster analysis (HCA), principal component analysis (PCA), and orthogonal partial least square-discriminant analysis (OPLS-DA) were used to classify two kinds of Hawk tea. Finally, the contribution of different phenolic compounds in Hawk tea to antioxidation was discussed by partial least square regression analysis (PLSR). The results were as follows: (1) The contents of catechin, p-coumaric acid, isoquercitrin, hyperoside, nicotiflorin, astragalin, kaempferol, quercetin, and afzelin in tender leaf tea were significantly higher than those in old leaf tea, among which the average contents of catechin, isoquercitrin, and astragalin were higher than those in old leaf tea by 1 039.43, 169.12 and 257.35 mg·100 g-1, respectively. The results of HCA, PCA, and OPLS-DA could distinguish two kinds of Hawk tea. (2) The ANOVA showed significant differences in DPPH radical scavenging rate, ABTS+ radical scavenging rate, and FRAP between two kinds of tea, with the tender leaf tea superior to the old leaf tea. (3) The PLSR suggested that isoquercitrin, catechin, astragalin, chlorogenic acid, hyperoside, p-coumaric acid, and kaempferol were the main phenolic compounds those contributed to the antioxidant activity of Hawk tea. This study can provide a reference for Hawk tea's quality control and application promotion.

To study the difference in the contents of phenolics and the antioxidant activities between two kinds of Hawk tea of different maturity levels, and to evaluate their qualities, the contents of 15 phenolic compounds were determined using LC-MS/MS method. Then, the antioxidant activities of two types of tea were evaluated using DPPH radical scavenging rate, ABTS+ radical scavenging rate, and Fe3+ ferric reducing antioxidant power(FRAP). And then, the contents of 15 phenolic compounds and the antioxidant activities between two kinds of Hawk tea of different maturity levels were analyzed by analysis of variance(ANOVA). Based on the contents of 15 phenolic compounds, hierarchical cluster analysis(HCA), principal component analysis(PCA), and orthogonal partial least square-discriminant analysis(OPLS-DA)were used to classify two kinds of Hawk tea. Finally, the contribution of different phenolic compounds in Hawk tea to antioxidation was discussed by partial least square regression analysis(PLSR). The results were as follows:(1)The contents of catechin, p-coumaric acid, isoquercitrin, hyperoside, nicotiflorin, astragalin, kaempferol, quercetin, and afzelin in tender leaf tea were significantly higher than those in old leaf tea, among which the average contents of catechin, isoquercitrin, and astragalin were higher than those in old leaf tea by 1 039.43, 169.12 and 257.35 mg·100 g-1, respectively. The results of HCA, PCA, and OPLS-DA could distinguish two kinds of Hawk tea.(2)The ANOVA showed significant differences in DPPH radical scavenging rate, ABTS+ radical scavenging rate, and FRAP between two kinds of tea, with the tender leaf tea superior to the old leaf tea.(3)The PLSR suggested that isoquercitrin, catechin, astragalin, chlorogenic acid, hyperoside, p-coumaric acid, and kaempferol were the main phenolic compounds those contributed to the antioxidant activity of Hawk tea. This study can provide a reference for Hawk tea's quality control and application promotion. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Hawk tea, a medicinal and edible plant, has been consumed for thousands of years in Southwest China. To date, no unified food safety standard for Hawk tea has been established, and systematic research on the quality of Hawk tea is lacking. Objective: The aim of this study was to develop a comprehensive evaluation method for the quality of Hawk tea based on inclusions content, high‐performance liquid chromatography (HPLC) fingerprinting combined with the quantitative analysis of multiple components with a single marker (QAMS) method. Methods: The contents of total flavonoids, total phenols, total polysaccharides, and total protein were determined using the colorimetric method. An effective comprehensive evaluation method was established to classify the 16 batches of samples based on HPLC fingerprint analysis combined with similarity analysis (SA), hierarchical cluster analysis (HCA), principal component analysis (PCA), partial least‐squares discrimination analysis (PLS‐DA), and the QAMS method. Results: Flavonoids were the main chemical components of Hawk tea. The accuracy of the QAMS method was verified by comparing the calculated results with those of the external standard method (ESM). No significant differences were found between the two methods. Additionally, the fingerprint of Hawk tea was also established. Conclusion: The method established in this study can be used for the comprehensive quality evaluation of Hawk tea and can also provide a reference for the quality evaluation of other herbal medicines. The flavonoids were the main chemical components of Hawk tea. The accuracy of the QAMS method was verified by comparing the calculated results with those of the external standard method (ESM). No significant differences were found between the two methods. Additionally, the fingerprint of Hawk tea was also established. The method established in this study can be used for the comprehensive quality evaluation of Hawk tea and can also provide a reference for the quality evaluation of other herbal medicines. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the metabolites in insect tea and hawk tea were analyzed by ultra-high performance liquid chromatography–triple quadrupole mass spectrometry. We found 49 metabolites in insect tea and hawk tea that can be used as key active components in traditional Chinese medicine, as well as 98 metabolites that can be used as active components of pharmaceutical preparations for the treatment of cancers, hypertension, cardiovascular diseases, etc. Comparative analysis found that insect tea and hawk tea had significant differences in their metabolic profiles. Insect tea contains more metabolites beneficial to human health than hawk tea; insect tea also has higher antioxidant activity in vitro than hawk tea. The results of this study will contribute to the development of new health foods using insect tea. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hawk black tea exhibited a fresh, sweet and sweet aftertaste qualities, while hawk white tea showed a mellow and pure taste. • Amino acids, soluble sugars and tea polyphenols differed significantly between the two types of hawk tea. • Ten substances such as butin, phlorizin, naringin are the key metabolites affecting the taste difference of hawk black and white tea. • The absence of caffeine in hawk tea opens up the possibility of developing caffeine-based beverages in the future. This study conducted a comprehensive analysis of the differences in the taste characteristics of hawk black tea and hawk white tea, exploring the intrinsic relationship between nonvolatile metabolites and these taste characteristics. The results revealed significant differences in taste properties of the two types of hawk tea. Hawk black tea mainly exhibits a fresh, sweet, and sweet aftertaste quality, whereas hawk white tea offers a mellow and pure taste. Comparative analysis revealed that the content of amino acids and carbohydrates in hawk black tea was significantly higher than that in hawk white tea, while the content of flavonoids and organic acids was relatively lower. Quality composition results indicated significant differences in the 13 major quality components and water extracts between the two hawk teas, aligning with the quantitative descriptive analysis results. Additionally, through weighted gene coexpression network analysis, significant associations were found between 671 metabolites across 155 metabolic pathways and 9 taste characteristics. Among them, flavonoid biosynthesis and degradation are the main metabolic pathways of the two types of hawk tea. And it was found that butin, phlorizin, naringin, dihydrokaempferol, sakuranetin, apigenin, (−)-epicatechin, (+)-gallocatechin, caffeoyl shikimic acid, homoeriodictyol, which are 10 flavonoids, are the key metabolites affecting the taste difference of hawk black and white tea. Additionally, this study found that hawk tea does not contain caffeine, which is of great significance for the development of caffeine-free beverages in the future. [ABSTRACT FROM AUTHOR]

Hawk tea (Litsea coreana Levl. var. lanuginosa) is a traditional herbal tea in southwestern China, and was found to possess hepatoprotective effects in our previous study. However, it is unclear whether hawk tea flavonoids (HTF) can alleviate alcoholic liver damage (ALD). Firstly, we extracted and identified the presence of 191 molecules categorized as HTFs, with reynoutrin, avicularin, guaijaverin, cynaroside, and kaempferol-7-O-glucoside being the most prevalent. After taking bioavailability into consideration and conducting comprehensive sorting, the contribution of guaijaverin was the highest (0.016 mg/mice). Then, by daily intragastric administration of HTF (100 mg/kg/day) to the ALD mice, we found that HTF alleviated liver lipid deposition (inhibition of TG, TC, LDL-C) by reducing liver oxidative-stress-mediated inflammation (up-regulation NRF2/HO-1 and down-regulation TLR4/MyD88/NF-κB pathway) and reshaping the gut microbiota (Lactobacillus, Bifidobacterium, Bacillus increased). Overall, we found HTF could be a potential protective natural compound for treating ALD via the gut–liver axis and guaijaverin might be the key substance involved. [ABSTRACT FROM AUTHOR]

Processing techniques are critical factors influencing the quality of hawk tea, yet systematic studies on their effects are limited. This study investigates the impact of four key processing procedures—fixation, reddening, fermentation, and compressing—using sensory evaluation, LC-MS/MS, and GC × GC-TOF-MS. Analysis identified 6951 non-volatile metabolites, including 107 marker metabolites, primarily in flavonoid synthesis and degradation pathways. Fermentation increased sweetness and richness by enhancing sugars and amino acid content, while significantly reducing flavonoid levels. Reddening improved flavor, color, and retained more beneficial flavonoids. Volatile analysis detected over 1800 compounds, including 398 volatile marker metabolites. Fermentation increased alcohols and heterocyclic compounds, reducing hydrocarbons and ketones. Additionally, 26 camphoraceous and 12 pungent aroma compounds characteristic of hawk tea were identified, and an aroma-flavor correlation map was established. By elucidating the impact of processing methods on its chemical and sensory properties, this study lays the groundwork for targeted quality control of hawk tea. [Display omitted] • 107 non-volatile marker metabolites were identified by LC-MS/MS, and 398 volatile marker metabolites by GC × GC-TOF-MS. • The main differential pathways in various hawk teas are linked to flavonoid biosynthesis and degradation. • The 180-min reddening process enhances hawk tea's taste while retaining relatively more bioactive compounds. • 2,3-Butanedione may be a key component contributing to the pleasant aroma of fermented hawk tea. • A comprehensive flavor-sensory and compound correlation network of hawk tea was established for the first time. [ABSTRACT FROM AUTHOR]

In this study, the metabolites in insect tea and hawk tea were analyzed by ultra-high performance liquid chromatography–triple quadrupole mass spectrometry. We found 49 metabolites in insect tea and hawk tea that can be used as key active components in traditional Chinese medicine, as well as 98 metabolites that can be used as active components of pharmaceutical preparations for the treatment of cancers, hypertension, cardiovascular diseases, etc. Comparative analysis found that insect tea and hawk tea had significant differences in their metabolic profiles. Insect tea contains more metabolites beneficial to human health than hawk tea; insect tea also has higher antioxidant activity in vitro than hawk tea. The results of this study will contribute to the development of new health foods using insect tea.

Copyright of Acta Agriculturae Zhejiangensis is the property of Acta Agriculturae Zhejiangensis Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigated the effect of storage time on biochemical characteristics of hawk tea (Litsea coreana) and explored the correlation between the content of flavonoids and polyphenols and antioxidant activity. The antioxidant activity and the content of inclusions, amino acid, and mineral elements in hawk tea processed by boiling water fixation and packed in airtight polypropylene bags and stored in 0°C refrigerator under different storage time (one year, three years, and six years) were analyzed. Results indicated that the biochemical characteristics of hawk tea changed less within 12 months. The total content and types of amino acids in hawk tea reached the maximum in the third year, as well as the content of total trace elements. The water extracts, tea polyphenol, caffeine, lysine, valine, isoleucine, glycine, proline, Ca, and Zn decreased continuously in the storage period of 6 years, but the total flavonoids, Mg, and Ni changed just the opposite. Total polyphenol is the main antioxidant material in hawk tea. Results of the present study provided useful information for people to systematically understand the changes of tea in the storage process and to reasonably develop hawk tea product. [ABSTRACT FROM AUTHOR]

Fixation is one of the critical steps in tea processing and can cause various physico-chemical changes, thus affecting tea quality. There are many tea processing techniques, but their influence on quality remains unclear. Here, we studied the impact of different fixation methods, including for 6 or 10 min by machine, by iron pan, or by boiling water, on the biochemical characteristics of hawk tea. The results showed that tea fixation technique had a significant influence on the sensory quality, biochemical components, and antioxidant activity of the tea. Compared to other fixation techniques, fixation by boiling water produced a more nutritious hawk tea with stronger DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity (EC50 = 6.56 μg/mL). Processing with boiling water also resulted in a better sensory quality with a unique sweet aftertaste. This tea also contained more polyphenols (19.60%), total amino acids (21,219 mg/100 g), essential amino acids (10,564 mg/100 g), and trace elements (5873.13 mg/kg). These results can guide the development of hawk tea products. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• A new polysaccharide (HTP-1) was isolated from Hawk tea. • The structural features of HTP-1were characterized using multiple analysis methods. • HTP-1 exhibited significant immunoregulatory activities. • The immunomodulatory action of HTP-1 might rely on the regulation of the gut microbiota. In this study, a novel 28.6 kDa acidic polysaccharide (HTP-1), containing → 4)-Gal p A-(1→, →2)-Rha p -(1 → and → 3,6)-Gal p -(1 → residues as the backbone, analogous to pectin, was isolated from mature Hawk tea leaves. HTP-1 exhibited significant immunoregulatory activities on CTX-induced immunosuppressed mice in a dose-depend manner by alleviating jejunum injury and improving the levels of immune organ indexes, cytokines and immunoglobulins. Moreover, HTP-1 supplementation boosted the content of SCFAs, altered the intestinal microbiota composition, and raised the abundances of beneficial bacteria Muribaculaceae , Lactobacillaceae , Bacteroidaceae , Prevotellaceae and Ruminococcaceae , which showed a strong positive correlation with most immune indicators. The current findings suggested that the immunomodulatory action of HTP-1 might rely on the regulation of the gut microbiota, and these results may also serve as a foundation for the future exploitation of HTP-1 as functional foods. [ABSTRACT FROM AUTHOR]

Hawk tea is a rich and edible resource, traditionally used as a beverage in South China. This drink has many pharmacologic effects, such as acting as an antioxidant and reducing blood sugar and lipids. The objective of this work was to explore the active compound contents, bioactivities and their monthly changes, and optimize the harvest time. In the present study, Hawk tea from each month in 2017 was collected and extracted with 70% (v/v) ethanol. The contents of the total flavonoids and total phenols were determined using the colorimetric method. We determined the contents of seven characteristic active substances—hyperin, isoquercitrin, trifolin, quercitrin, astragalin, quercetin, and kaempferol—using high-performance liquid chromatography. The crude extract was tested for its antioxidant and inhibitory properties on enzymes involved in metabolic syndrome. Specifically, 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid), ferric-reducing power assay, and the inhibition capacity test on α-glucosidase and lipase were conducted to determine the antioxidant effect in vitro, as well as the reduction of blood sugar and lipids. Monthly variations in activities and components were determined by numeric analysis and comparison. Correlation analysis revealed that antioxidant effects are significantly correlated with the total flavonoids. The hierarchical cluster analysis of bioactivities and their contents indicates that October and November are the best harvesting months, which differs with the habitual collection of Hawk tea.

Hawk tea (Litsea coreana Lévl. var. Lanuginosa (Migo) Yen C. Yang & P.H. Huang), a very popular herbal tea material, has attracted more and more attention due to its high antioxidant properties and possible therapeutic effect on type II diabetes mellitus. The raw materials of Hawk tea are usually divided into three kinds: bud tea (BT), primary leaf tea (PLT) and mature leaf tea (MLT). In this study, the DPPH radical scavenging activity and the antimicrobial properties of these three kinds of Hawk tea from different regions were comparatively investigated, and a ultra-high performance liquid chromatographic coupled with a photodiode array detector (UPLC-DAD) method was employed for comparison of the three major flavonoid constituents, including hyperoside, isoquercitrin and astragalin, in different samples of Hawk tea. At the same time, the effect of methanol extract (ME) of PLT on the mouse postprandial blood glucose and the effect of ME and its different fractions (petroleum ether fraction (PE), ethyl acetate fraction (EA), n-butanol fraction (n-BuOH), and water fraction (WF)) on the activity of α-glucosidase were studied. The results showed that Hawk BT and Hawk PLT possessed the higher radicals scavenging activity than Hawk MLT, while the antibacterial activity against P. vulgaris of PLT and MLT was higher than Hawk BT. The contents of the three major flavonoid constituents in samples of Hawk PLT are higher than Hawk BT and Hawk MLT. The mouse postprandial blood glucose levels of the middle dose (0.5 g/kg) group and the high dose (1 g/kg) group with oral administration of the ME of PLT were significantly lower than the control group. What's more, the inhibitory effect of ME of PLT and its EA and n-BuOH fractions on α-glucosidase was significantly higher than that of acarbose. Rapid ultra-high performance liquid chromatography/quadrupole time-of-flight-mass spectrometry (UPLC-ESI-QTOF-MS) was used to identify the flavonoids in Hawk PLT, and a total of 20 flavonoids were identified or tentatively identified by comparing their retention times and accurate mass measurements with reference compounds or literature data. The bioactive flavonoid composition and DPPH radical scavenging activities present in different Hawk tea raw materials are quite different due to the different ontogenesis of these raw materials. Further studies on PLT showed that the substances in PLT ME could reduce the level of mouse postprandial blood glucose through inhibiting the activity of α-glucosidase. [ABSTRACT FROM AUTHOR]

Hawk tea (Litsea coreana Lévl. var. Lanuginosa (Migo) Yen C. Yang & P.H. Huang), a very popular herbal tea material, has attracted more and more attention due to its high antioxidant properties and possible therapeutic effect on type II diabetes mellitus. The raw materials of Hawk tea are usually divided into three kinds: bud tea (BT), primary leaf tea (PLT) and mature leaf tea (MLT). In this study, the DPPH radical scavenging activity and the antimicrobial properties of these three kinds of Hawk tea from different regions were comparatively investigated, and a ultra-high performance liquid chromatographic coupled with a photodiode array detector (UPLC-DAD) method was employed for comparison of the three major flavonoid constituents, including hyperoside, isoquercitrin and astragalin, in different samples of Hawk tea. At the same time, the effect of methanol extract (ME) of PLT on the mouse postprandial blood glucose and the effect of ME and its different fractions (petroleum ether fraction (PE), ethyl acetate fraction (EA), n-butanol fraction (n-BuOH), and water fraction (WF)) on the activity of α-glucosidase were studied. The results showed that Hawk BT and Hawk PLT possessed the higher radicals scavenging activity than Hawk MLT, while the antibacterial activity against P. vulgaris of PLT and MLT was higher than Hawk BT. The contents of the three major flavonoid constituents in samples of Hawk PLT are higher than Hawk BT and Hawk MLT. The mouse postprandial blood glucose levels of the middle dose (0.5 g/kg) group and the high dose (1 g/kg) group with oral administration of the ME of PLT were significantly lower than the control group. What's more, the inhibitory effect of ME of PLT and its EA and n-BuOH fractions on α-glucosidase was significantly higher than that of acarbose. Rapid ultra-high performance liquid chromatography/quadrupole time-of-flight-mass spectrometry (UPLC-ESI-QTOF-MS) was used to identify the flavonoids in Hawk PLT, and a total of 20 flavonoids were identified or tentatively identified by comparing their retention times and accurate mass measurements with reference compounds or literature data. The bioactive flavonoid composition and DPPH radical scavenging activities present in different Hawk tea raw materials are quite different due to the different ontogenesis of these raw materials. Further studies on PLT showed that the substances in PLT ME could reduce the level of mouse postprandial blood glucose through inhibiting the activity of α-glucosidase. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the flavonoids compositions, content and antioxidant activities of Hawk tea from six botanical origins for screening the most suitable botanical origins. The main flavonoids of Hawk teas from Litsea coreana Levl. var. lanuginose were identified, and six high contents of individual flavonoids (hyperin, isoquercitrin, quercitrin, astragalin, quercetin and kaempferol) were quantitative and comparative analysis. Moreover the potential antioxidant capacity of Hawk tea was measured by using in vitro antioxidant assays. The above experimental data were all used for the principal component analysis. The statistical results showed that the extracts from Machilus chuanchienensis S. Lee and L. coreana Levl. var. lanuginose appeared closely positioned in the positive regions, indicated the higher flavonoids and antioxidant activity compared with other species. Thus, they were temporarily considered as good sources of Hawk tea. [ABSTRACT FROM AUTHOR]

Hawk tea (Litsea coreana Lévl. var. Lanuginosa (Migo) Yen C. Yang & P.H. Huang), a very popular herbal tea material, has attracted more and more attention due to its high antioxidant properties and possible therapeutic effect on type II diabetes mellitus. The raw materials of Hawk tea are usually divided into three kinds: bud tea (BT), primary leaf tea (PLT) and mature leaf tea (MLT). In this study, the DPPH radical scavenging activity and the antimicrobial properties of these three kinds of Hawk tea from different regions were comparatively investigated, and a ultra-high performance liquid chromatographic coupled with a photodiode array detector (UPLC-DAD) method was employed for comparison of the three major flavonoid constituents, including hyperoside, isoquercitrin and astragalin, in different samples of Hawk tea. At the same time, the effect of methanol extract (ME) of PLT on the mouse postprandial blood glucose and the effect of ME and its different fractions (petroleum ether fraction (PE), ethyl acetate fraction (EA), n-butanol fraction (n-BuOH), and water fraction (WF)) on the activity of α-glucosidase were studied. The results showed that Hawk BT and Hawk PLT possessed the higher radicals scavenging activity than Hawk MLT, while the antibacterial activity against P. vulgaris of PLT and MLT was higher than Hawk BT. The contents of the three major flavonoid constituents in samples of Hawk PLT are higher than Hawk BT and Hawk MLT. The mouse postprandial blood glucose levels of the middle dose (0.5 g/kg) group and the high dose (1 g/kg) group with oral administration of the ME of PLT were significantly lower than the control group. What’s more, the inhibitory effect of ME of PLT and its EA and n-BuOH fractions on α-glucosidase was significantly higher than that of acarbose. Rapid ultra-high performance liquid chromatography/quadrupole time-of-flight-mass spectrometry (UPLC-ESI-QTOF-MS) was used to identify the flavonoids in Hawk PLT, and a total of 20 flavonoids were identified or tentatively identified by comparing their retention times and accurate mass measurements with reference compounds or literature data. The bioactive flavonoid composition and DPPH radical scavenging activities present in different Hawk tea raw materials are quite different due to the different ontogenesis of these raw materials. Further studies on PLT showed that the substances in PLT ME could reduce the level of mouse postprandial blood glucose through inhibiting the activity of α-glucosidase.

In this work, the QuEChERS method was modified and evaluated for the determination of 186 pesticides from caffeine-free and fatty hawk tea prior to their gas chromatography tandem mass spectrometry analysis for the first time. The results showed that the combination of MgSO 4 + PSA + MWCNTs plus EMR-Lipid provided the lowest matrix effect and best recovery; 117 of 186 pesticides manifested weak matrix effects. Thus, for accurate quantification, it is necessary to use matrix-matched calibration curves to compensate for the matrix effect. At the spiked level of 0.1 mg/kg, the average recoveries of 184 pesticides were in the range of 70-120% and the RSDs were 0.3-14.4% by the modified method. Good linearity was shown for 186 analytes at concentration of 0.01 mg/L~0.4 mg/L, and the correlation coefficients exceeded 0.99 for 182 pesticides. The detection limits of 186 pesticides by the modified QuEChERS method were 0.001-0.02 mg/kg, and the limits of quantification (LOQ) were 0.005 mg/kg~0.05 mg/kg. The necessity of solvent exchange is also explained in this work. The successful application of the modified QuEChERS in real samples proved that this method could be one of the routine options for analysis of herbal tea.

Hawk tea (HT), made from the leaves of Litsea coreana Levl. var. lanuginosa , is a traditional Chinese herbal tea. Different processing methods alter the chemical composition of the HT, which changes the sensory qualities and pharmacological properties. The chemical composition, sensory qualities, antioxidant activities, and potential hepatoprotection (ameliorating acute alcoholic liver damage using a mouse model) of pan-fried (PFHT), sun-dried (SDHT), and fermented hawk tea (FHT) were investigated. PFHT had the highest level of phenolics and flavonoids, followed by SDHT and FHT. The highest levels of total and floral/fruit-like volatiles were observed in FHT, which had the highest overall sensory acceptance using a consumer panel. The PFHT and SDHT showed stronger antioxidant activity than FHT. The HT aqueous extracts showed similar hepatoprotective effects in the mouse model, among which PFHT aqueous extracts were the most effective in suppressing hepatic steatosis. PFHT showed the highest health-promoting value with the highest yield of aqueous extracts and the best protective effects against alcoholic liver damage. [ABSTRACT FROM AUTHOR]

Hawk tea is a rich and edible resource, traditionally used as a beverage in South China. This drink has many pharmacologic effects, such as acting as an antioxidant and reducing blood sugar and lipids. The objective of this work was to explore the active compound contents, bioactivities and their monthly changes, and optimize the harvest time. In the present study, Hawk tea from each month in 2017 was collected and extracted with 70% (v/v) ethanol. The contents of the total flavonoids and total phenols were determined using the colorimetric method. We determined the contents of seven characteristic active substances—hyperin, isoquercitrin, trifolin, quercitrin, astragalin, quercetin, and kaempferol—using high-performance liquid chromatography. The crude extract was tested for its antioxidant and inhibitory properties on enzymes involved in metabolic syndrome. Specifically, 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid), ferric-reducing power assay, and the inhibition capacity test on α-glucosidase and lipase were conducted to determine the antioxidant effect in vitro, as well as the reduction of blood sugar and lipids. Monthly variations in activities and components were determined by numeric analysis and comparison. Correlation analysis revealed that antioxidant effects are significantly correlated with the total flavonoids. The hierarchical cluster analysis of bioactivities and their contents indicates that October and November are the best harvesting months, which differs with the habitual collection of Hawk tea. [ABSTRACT FROM AUTHOR]

Hawk tea ( Litsea coreana Lévl. var. Lanuginosa (Migo) Yen C. Yang & P.H. Huang), a very popular herbal tea material, has attracted more and more attention due to its high antioxidant properties and possible therapeutic effect on type II diabetes mellitus. The raw materials of Hawk tea are usually divided into three kinds: bud tea (BT), primary leaf tea (PLT) and mature leaf tea (MLT). In this study, the DPPH radical scavenging activity and the antimicrobial properties of these three kinds of Hawk tea from different regions were comparatively investigated, and a ultra-high performance liquid chromatographic coupled with a photodiode array detector (UPLC-DAD) method was employed for comparison of the three major flavonoid constituents, including hyperoside, isoquercitrin and astragalin, in different samples of Hawk tea. At the same time, the effect of methanol extract (ME) of PLT on the mouse postprandial blood glucose and the effect of ME and its different fractions (petroleum ether fraction (PE), ethyl acetate fraction (EA), n -butanol fraction ( n -BuOH), and water fraction (WF)) on the activity of α-glucosidase were studied. The results showed that Hawk BT and Hawk PLT possessed the higher radicals scavenging activity than Hawk MLT, while the antibacterial activity against P. vulgaris of PLT and MLT was higher than Hawk BT. The contents of the three major flavonoid constituents in samples of Hawk PLT are higher than Hawk BT and Hawk MLT. The mouse postprandial blood glucose levels of the middle dose (0.5 g/kg) group and the high dose (1 g/kg) group with oral administration of the ME of PLT were significantly lower than the control group. What's more, the inhibitory effect of ME of PLT and its EA and n -BuOH fractions on α-glucosidase was significantly higher than that of acarbose. Rapid ultra-high performance liquid chromatography/quadrupole time-of-flight-mass spectrometry (UPLC-ESI-QTOF-MS) was used to identify the flavonoids in Hawk PLT, and a total of 20 flavonoids were identified or tentatively identified by comparing their retention times and accurate mass measurements with reference compounds or literature data. The bioactive flavonoid composition and DPPH radical scavenging activities present in different Hawk tea raw materials are quite different due to the different ontogenesis of these raw materials. Further studies on PLT showed that the substances in PLT ME could reduce the level of mouse postprandial blood glucose through inhibiting the activity of α-glucosidase., Competing Interests: The authors declare no conflict of interest.

In this study, volatile oils of six Hawk tea varieties were studied for their chemical composition, antioxidant and antimicrobial activities to screen the most suitable botanical origins of Hawk tea. A total of 72 components were separated and identified from the six oils. The major constituents of the volatile oils were: α-pinene, camphene, limonene, 1,8-cineole, linalool, cis-nerolidol, and germacrene B. Moreover, the volatile oils were evaluated for antioxidant potential and antimicrobial activities. The results showed that all volatile oils exhibited acceptable antioxidant and antimicrobial activities, which suggested that these volatile oils may serve as natural alternatives to synthetic antioxidants and preservatives to be applied in food and pharmaceutical industries. Principal component analysis results denoted that some major compounds may be closely related to the antioxidant and antimicrobial activities. It also showed that the volatile oils from Litsea coreana var. lanuginosa and Litsea pungens Hemsl. were characterized by positive values of first two principal components, indicating higher active chemical compounds and antioxidant and antimicrobial activities compared with other species. Thus, they were temporarily considered as good sources of Hawk tea., (© 2016 Wiley-VHCA AG, Zurich, Switzerland.)

Hawk tea (Litsea coreana Levl. var. lanuginose) is a traditional Chinese drink similar to green tea. In the present study, the preventive effects of Hawk tea on hepatic damage induced by carbon tetrachloride (CCl(4)) were studied in Sprague-Dawley rats. Silymarin was used as a positive control. Hawk tea was successfully shown to prevent hepatic damage in the rats. Serum levels of AST, ALT and LDH were significantly decreased when the rats were treated with varying concentrations of Hawk tea compared with silymarin (P<0.05). The lowest enzyme activities were exhibited in the 400 mg/kg Hawk tea group. This group showed reduced levels of the serum proinflammatory cytokines IL-6, IFN-γ and TNF-α. In particular, the IFN-γ level decreased markedly compared with the other concentration groups. The histopathology sections of liver tissue in the 400 mg/kg Hawk tea group recovered well from the CCl(4) damage, but the sections of the other concentration groups showed necrosis to a more serious degree. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot analyses of the inflammation-related genes iNOS, COX-2, TNF-α and IL-1β in the rat livers were tested. The 400 mg/kg Hawk tea group showed significantly decreased mRNA and protein expression levels of iNOS, COX-2, TNF-α and IL-1β compared with the control group. Accordingly, 400 mg/kg Hawk tea potentially contributes to the prevention of CCl(4)-induced hepatic damage in vivo. A 200 or 100 mg/kg dose of Hawk tea also demonstrated preventive effects against hepatic damage.