Preliminary structural characterization and antioxidant activities of polysaccharides extracted from Hawk tea (Litsea coreana var. lanuginosa)

Ultrasound-assisted complex enzyme extraction, structural characterization, and biological activity of polysaccharides from Ligustrum robustum

Ligustrum robustum is one of the traditional teas in China with a long history of drinking and medicinal use. Through Response surface optimization, the yield of polysaccharides extracted by ultrasonic-assisted complex enzyme (UAE-EN) method was increased to 14.10 ± 0.56 %. Neutral homogeneous polysaccharide (LRNP) and acidic homogeneous polysaccharide (LRAP-1, LRAP-2, LRAP-3) from L. robustum were purified. The molecular weights of them were 5894, 4256, 4621 and 3915 Da. LRNP was composed of glucose (Glc), galactose (Gal), arabinose (Ara) with molar percentage of 24.97, 42.38 and 30.80. Structure analysis revealed that the backbone of LRNP consisted of 1,5-linked α-Araf, 1,4-linked β-Galp, 1,6-linked β-Galp, and 1,4-linked β-Glcp with the branches of 1,2-linked α-Araf, 1,3-linked α-Araf, 1,3-linked β-Glcp and 1,6-linked β-Galp residues, some terminal residues of α-Araf, β-Glcp and α-Galp were also included. In vitro experiments showed that the four polysaccharides possessed excellent antioxidant, antitumor and hypoglycemic activities. LRNP possessed the protective effect against oxidative stress. The studies provide a basis for further exploitation of L. robustum.

Study of the Mechanism of Hydrolysis of Hemicellulose from Lignocellulose during Alkali Thermal Pretreatment by Density Functional Theory and Experiment

The covalent bond fracture of hemicellulose leads to hemicellulose hydrolysis during lignocellulosic alkali thermal pretreatment, which has not previously been reported. Density functional theory was used to study the mechanism of hydrolysis of the hemicellulose model compounds under alkali conditions. There are four reaction paths for xylose formation, among which the reaction path with the lowest energy barrier is that in which the nucleophile captures H30 to generate water. The deprotonated hydroxyl group attacks the carbon on the glycoside bond, resulting in the cleavage of the glycoside bond and the formation of a new carbon-oxygen covalent bond, with an energy barrier of 154.2 kJ/mol. The nucleophile further attacks the glycosidic bond to form a new xylose residue with an energy barrier of 111.9 kJ/mol. When the glycosidic bond breaks, the orbital interaction with the largest proportion causes the transfer of ∼0.511 electron from the glycosidic bond oxygen to the deprotonated hydroxy oxygen. In situ Fourier transform infrared spectroscopy is used for the identification of functional groups during the alkali thermal pretreatment. As the temperature increases, the feasibility of the reaction increases. This study lays a theoretical foundation for the development of the alkali thermal pretreatment of lignocellulose.

Quality evaluation of Hawk tea from different months and regions based on quantitative analysis of multiple components with a single marker (QAMS) combined with HPLC fingerprint

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.

A new polysaccharide from Hawk tea: Structural characterization and immunomodulatory activity associated with regulating gut microbiota

In this study, a novel 28.6 kDa acidic polysaccharide (HTP-1), containing → 4)-GalpA-(1→, →2)-Rhap-(1 → and → 3,6)-Galp-(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 intestinalmicrobiota 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.

Production and characterization of exopolysaccharides from salinity-induced Auxenochlorella protothecoides and the analysis of anti-inflammatory activity

The set scenario of this work was to investigate the production, physicochemical characteristics, and anti-inflammatory activities of exopolysaccharides from salinity-induced Auxenochlorella protothecoides. The results demonstrated that 10 ‰ salinity manipulation endowed preferable exopolysaccharide production by A. protothecoides. Under this salinity stress, ACPEPS1A and ACPEPS2A were purified from exopolysaccharide production by anion chromatography and molecular exclusion chromatography. ACPEPS1A exhibited a molecular weight (Mw) of 132 kDa and mainly consisted of galactose. ACPEPS2A was a heteropolysaccharide with an Mw of 170 kDa and the main monosaccharides of galactose and rhamnose with separate molar percents of 42.41 % and 35.29 %, respectively. FTIR, ¹H and ¹³C NMR supported that monosaccharide components of ACPEPS1A and ACPEPS2A possessed both α- and β-configuration pyranose rings. Further evidence indicated that ACPEPS1A and ACPEPS2A could effectively inhibit the inflammatory response in lipopolysaccharide (LPS) induced RAW264.7 cells by quenching inflammatory factor levels such as ROS, iNOS, TNF-α, and IL-6. The potential anti-inflammatory possibilities were that the monosaccharides of ACPEPS1A and ACPEPS2A possessed higher affinity with receptors on the macrophage surface than LPS and hampered LPS-induced inflammation. The findings of this work would favor innovative applications of exopolysaccharides from microalgae in complementary medicines or functional foods.

The Complete Chloroplast Genome Sequence of Machilus chuanchienensis (Lauraceae): Genome Structure and Phylogenetic Analysis

Machilus chuanchienensis is an ecological tree distributed in southwestern China. It has a significant valuation with making Hawk tea using its leaves, an ethnic traditional tea-like beverage with a long history in Chinese tea culture. The whole chloroplast (cp) genome is an ideal model for the phylogenetic study of Lauraceae because of its simple structure and highly conserved features. There have been numerous reports of complete cp genome sequences in Lauraceae, but little is known about M. chuanchienensis. Here, the next-generation sequencing (NGS) was used to sequence the M. chuanchienensis cp genome. Then, a comprehensive comparative genome analysis was performed. The results revealed that the M. chuanchienensis's cp genome measured 152,748 base pairs (bp) with a GC content of 39.15% and coded 126 genes annotated, including comprising eight ribosomal RNA (rRNA), 36 transporter RNA (tRNA), and 82 protein-coding genes. In addition, the cp genome presented a typical quadripartite structure comprising a large single-copy (LSC; 93,811) region, a small single-copy (SSC; 18,803) region, and the inverted repeats (IRs; 20,067) region and contained 92 simple sequence repeat (SSR) locus in total. Phylogenetic relationships of 37 species indicated that M. chuanchienensis was a sister to M. balansae, M. melanophylla, and M. minutiflora. Further research on this crucial species may benefit significantly from these findings.

Rapid Analysis of Residues of 186 Pesticides in Hawk Tea Using Modified QuEChERS Coupled with Gas Chromatography Tandem Mass Spectrometry

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 MgSO₄ + 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.

A novel exopolysaccharide produced by Zygosaccharomyces rouxii with cryoprotective and freeze-drying protective activities

In the present work, a novel exopolysaccharide EPS-3791 was extracted and purified from a salt-tolerant yeast, Zygosaccharomyces rouxii. Structural analyses showed that EPS-3791 was composed of galactose, glucose and mannose in a molar ration of 1.00: 4.25: 13.30 with a molecular weight of 64.412 kDa. Fourier transform infrared spectroscopy manifested the main functional groups, α- and β- configurations. Methylated analysis indicated T-Manp-(1→, →2)-Glcp-(1 → and → 2,6)-Manp-(1 → were the main linkages. 800 MHz nuclear magnetic resonance spectroscopy demonstrated the EPS-3791 structure of a novel main chain and branched chain. Atomic force microscope and scanning electron microscope revealed a homogeneous and uniform porous structure. In addition, EPS-3791 was proven to have cryoprotective and freeze-drying protective effects on Lactococcus lactis, and exhibited better protective performance than that of trelahose during freeze-drying of L. lactis, suggesting that EPS-3791 could be developed into cryoprotectant or lyoprotectant applied in food industry.

Anti-inflammatory and antioxidant activity of the hot water-soluble polysaccharides from Anacyclus pyrethrum (L.) Lag. roots

ETHNOPHAMACOLOGICAL RELEVANCE: the roots of Anacyclus pyrethrum (L.) Lag. (Family: Asteraceae) are used in Algeria to treat respiratory infections, to cure chronic head and nostrils catarrh, and to clear the brain by stimulating the free flow of nasal mucous. They contain a high quantity of hot water-soluble polysaccharides.

AIMS OF THE STUDY

The study aims to evaluate the antioxidant and anti-inflammatory activity of polysaccharides extracted from Anacyclus pyrethrum roots (APPS).

MATERIALS AND METHODS

The APPS were extracted using boiling water, separated from proteins by the Sevag method then precipitated with 90% ethanol. The antioxidant effect of crude APPS was evaluated using FRAP assay. To investigate the anti-inflammatory potential, mice were treated with crude polysaccharides (25, 50, and 100 mg/kg, i.p.) for 3 days (14th, 15th, and 16th day of the experimentation). Respiratory inflammation was induced by HDM (House Dust Mite), mice were sensitized intranasally with 25 μg HDM suspended in 10 μl NaCl (5 μl/nostril) on days 0 and 7 then challenged with 5 μg HDM on days 14, 15, and 16. Mice were sacrificed 24 h after the last challenge. The number of immune cells in the blood in NL (Nasal Liquid) and in BAL (Broncho Alveolar Liquid) was enumerated, the spleen was removed to calculate the relative spleen weight and to count splénocytes, lungs histopathological examination was carried out to confirm the protective effect of APPS. Structural characterization of APPS was identified using FTIR (Fourier-Transform Infrared Spectroscopy) and SEM (Scanning Electron Microscopy).

RESULTS

The crude APPS possessed reducing power. In vivo assay, treatment with APPS causes a decrease in the number of blood leucocytes at all doses on the one hand, and in the relative spleen weight and splénocytes number on the other hand except at the dose of 50 mg/kg in which an enhancement of the number of splénocytes and immune cells in NL and BAL was significant. The histopathological examination showed clear protection of lung tissue damaged by HDM, after treatment with APPS mainly, at the dose of 50 mg/kg.

CONCLUSION

Our data clearly showed antioxidant and anti-inflammatory activity of APPS on HDM-challenged mice induced lungs inflammation by equilibrating the inflammatory reaction mostly, with an optimal dose of 50 mg/kg.

Preparation and characterization of metal-tea polysaccharide complexes and their inhibition on α-glucosidase

The preparation method and the sources of metal elements may affect the activity of the metal-polysaccharide complex. In this study, four Fe-tea polysaccharide complexes were prepared and three tea polysaccharides (TPSs) from different seasons were extracted. Moreover, the binding mode of TPSs with internal and external metallic elements as well as their inhibitory effect on α-glucosidase was explored. The results revealed that the binding mode (-C-O-Fe and -C-Fe) of the Fe-TPS complex prepared at pH 5.0 was closer to TPS with internal metallic elements. The TPS with the least amount of internal metallic elements (61.72 mg/g) exhibited a high inhibitory activity on α-glucosidase (37.90%). The inhibitory activity of Fe-TPS on α-glucosidase was lower than that without Fe. But the quenching effect and the inhibition type of TPSs on α-glucosidase were not affected by metallic elements. Therefore, the metallic elements have the potential to reduce the hypoglycemic activity of TPS. PRACTICAL APPLICATIONS: In this paper, TPS was extracted from crude tea in different seasons, and the effects of metallic elements in TPS on hypoglycemic activity, physicochemical properties, and structure of TPS were discussed. TPS metal complexes were prepared by adding Fe³⁺ or removing metallic elements, and the differences of internal metallic elements in TPS were discussed. It is of great academic significance to use tea pruned leaves and crude tea as potential resources to develop polysaccharide hypoglycemic products and to reveal the relationship between TPS metal ions and their structure and activity. In addition, it has guiding value for consumers to choose tea-producing regions and growers to choose chemical fertilizer.

A strategy for the synthesis of low-molecular-weight welan gum by eliminating capsule form of Sphingomonas strains

Welan gum is widely used in food, concrete additives, and oil recovery. Here we changed the capsule form of Sphingomonas strains by knocked out the sortase gene (srtW). The obtained welan gum was mainly composed of mannose, glucose, rhamnose, and glucuronic acid at a molar ratio of 4.0:5.8:1.6:1, respectively. Meanwhile, the molecular weight of welan gum decreased sharply (about 68 kDa). Moreover, the low molecular weight (LMW) welan gum was characterized by FT-IR and NMR spectroscopy. The rheological results revealed that the LMW welan gum solution is a pseudoplastic fluid with a lower apparent viscosity. Furthermore, the oscillation test illustrated stable dynamic viscoelasticity within the temperature range of 5-68 °C and frequency range of 0.01-15 rad/s. To the best of our knowledge, this is the first report of LMW welan gum production and characterization. These results provide references for LMW welan gum applications, and likely applicable for other biopolymers production.

A water-soluble polysaccharide from Anethum graveolens seeds: Structural characterization, antioxidant activity and potential use as meat preservative

A novel water-soluble polysaccharide named AGP1 was successfully isolated from seeds of Anethum graveolens by hot water extraction and further purified by DEAE-Sepharose chromatography. AGP1 has a relative molecular weight of 2.1 10⁴ Da determined by Ultra-high-performance liquid chromatography (UHPLC). The AGP1 characterization was investigated by chemical and instrumental analysis including gas chromatography mass spectrometry (GC-MS), Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction. Results showed that AGP1 was mainly composed of glucose, galactose, mannose and arabinose in a molar percent of 54.3, 23.8, 14.7 and 7.2, respectively. The thermogravimetry analysis (TGA) and the differential scanning calorimetry (DSC) were used and showed that AGP1 has good thermal stability until 275 °C. Moreover, the purified polysaccharide demonstrated an appreciable in vitro antioxidant potential. The addition of the AGP1, particularly at 0.3% (w/w), in turkey sausages instead of ascorbic acid, as preservative, reduced the lipid peroxidation, preserved the pH and color and improved the bacterial stability during cold storage at 4 °C for 12 days. Overall, the results showed that the AGP1 deserves to be developed as functional and bioactive components for the food and nutraceutical industries.

Optimization of ultrasonic-assisted extraction of polysaccharides from purple glutinous rice bran (Oryza sativa L.) and their antioxidant activities

Purple glutinous rice bran (Kum Doi Saket rice (KUM)) contains high content of edible polysaccharides and anthocyanins and has an excellent antioxidant activity. This research aimed to optimize the extraction of crude polysaccharides from defatted purple glutinous rice bran using an ultrasonic-assisted extraction (UAE) and compared with a hot water extraction (HWE). Results showed that optimal extraction condition was as follows: a defatted rice bran to water ratio of 1:20 w/v, extraction temperature and time of 70 °C for 20 min. Under the optimal extraction condition, the yield of polysaccharide of UAE (4%) was significantly higher than that obtained from the HWE (0.8%). Additionally, antioxidant activities of extracted polysaccharide including IC₅₀ value DPPH, IC₅₀ value ABTS, and FRAP value were 1.09 mg/mL, 2.80 mg/mL and 197 µM Fe²⁺/g, respectively. It is suggested that the UAE process is promising method to decrease the processing time and to enhance extracted polysaccharide yields by 4 times.

The impact of fixation method on the biochemical characteristics of hawk tea (Litsea coreana)

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.

Water-Soluble Polysaccharides from Ephedra alata Stems: Structural Characterization, Functional Properties, and Antioxidant Activity

In this study, the physicochemical characterization, functional properties, and antioxidant activity of polysaccharides extracted from Ephedra alata (EAP) were investigated. EAP were extracted in water during 3 h with a liquid/solid ratio of 5 in a water bath at 90 °C. The structure of the extracted EAP was examined by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and gas chromatography-mass spectrometry (GC-MS). The functional properties and biochemical activities of EAP were determined. The chemical analysis revealed that the contents of carbohydrates, uronic acid, and proteins were 73.24% ± 1.24%, 6.82% ± 0.57%, and 6.56% ± 0.36%, respectively. The results showed that the extracted EAP essentially contain three functional groups: C=O, C-H, and O-H. SEM images showed that EAP present numerous high porosity particles. The monosaccharide composition revealed a polymer composed of glucose (43.1%), galactose (36.4%), mannose (14.9%), arabinose (3.7%), and gluconic acid (1.7%). EAP showed interesting functional properties (solubility, oil holding capacity, foaming and emulsion properties). Finally, the results revealed that EAP displayed excellent antihypertensive and antioxidant activities. Overall, EAP present a promising natural source of food additives, antioxidants, and antihypertensive agents.

Processed Fruiting Bodies of Lentinus edodes as a Source of Biologically Active Polysaccharides

Water soluble polysaccharides (WSP) were isolated from Lentinus edodes fruiting bodies. The mushrooms were previously subjected to various processing techniques which included blanching, boiling, and fermenting with lactic acid bacteria. Therefore, the impact of processing on the content and biological activities of WSP was established. Non-processed fruiting bodies contained 10.70 ± 0.09 mg/g fw. Boiling caused ~12% decrease in the amount of WSP, while blanched and fermented mushrooms showed ~6% decline. Fourier transform infrared spectroscopy analysis (FTIR) confirmed the presence of β-glycosidic links, whereas due to size exclusion chromatography 216 kDa and 11 kDa molecules were detected. WSP exhibited antioxidant potential in FRAP (ferric ion reducing antioxidant power) and ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) assays. Cytotoxic properties were determined on MCF-7 and T47D human breast cell lines using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) test. Both biological activities decreased as the result of boiling and fermenting.

Optimization of Microwave-Assisted Extraction of Polysaccharides from Ulva pertusa and Evaluation of Their Antioxidant Activity

The use of green marine seaweed Ulva spp. as foods, feed supplements, and functional ingredients has gained increasing interest. Microwave-assisted extraction technology was employed to improve the extraction yield and composition of Ulva pertusa polysaccharides. The antioxidant activity of ulvan was also evaluated. The impacts of four independent variables, i.e., extraction time (X₁, 30 to 60 min), power (X₂, 500 to 700 W), water-to-raw-material ratio (X₃, 40 to 70), and pH (X₄, 5 to 7) were evaluated. The chemical structure of different polysaccharides fractions was investigated via FT-IR and the determination of their antioxidant activities. A response surface methodology based on a Box–Behnken design (BBD) was used to optimize the extraction conditions as follows: extraction time of 43.63 min, power level of 600 W, water-to-raw-material ratio of 55.45, pH of 6.57, and maximum yield of 41.91%, with a desired value of 0.381. Ulvan exerted a strong antioxidant effect against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and showed reducing power in vitro. Ulvan protected RAW 264.7 cells against H₂O₂-induced oxidative stress by upregulating the expression and enhancing the activity of oxidative enzymes such as superoxide dismutase (SOD) and superoxide dismutase (CAT). The results suggest that the polysaccharides from U. pertusa might be promising bioactive compounds for commercial use.

Active Components, Antioxidant, Inhibition on Metabolic Syndrome Related Enzymes, and Monthly Variations in Mature Leaf Hawk Tea

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.

Antioxidant activity of purified ulvan in hyperlipidemic mice

Several studies have reported that ulvan from the alga Ulva pertusa (Chlorophyta) exhibits substantial antioxidant and antihyperlipidemic activities; however, which group of heteropolysaccharides play roles in these activities remains unknown. In this study, three purified ulvan (PU1, PU2 and PU3) have been obtained by DEAE-Sepharose fast-flow column. The antioxidant activity was detected via the model of hyperlipidemic Kunming mice, including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in liver. PU3, which possessed the highest uronic acid content (24.09%) and sulfate content (23.99%) as well as the lowest average molecular weight (83,094 Da), exhibited the stronger antioxidant activity than other examples. It significantly decreased MDA (29.2%; P < 0.05), increased SOD (36.4%; P < 0.05) and CAT (43.6%; P < 0.05) compared with hyperlipidemia group. In conclusion, PU3 may be potential sources of natural antioxidant to protecting against the liver damage of oxidative stress induced by cholesterol-rich diet.

A review on phytochemical and pharmacological properties of Litsea coreana

CONTEXT

Litsea coreana H. Lév. (Lauraceae) is used as an ethnic herb or beverage in China. Substantial studies indicate that it contains a variety of compounds and shows diverse bioactivities with no toxicity.

OBJECTIVE

This review analyzes and summarizes the ethnopharmacological applications, phytochemistry, and pharmacological activities and molecular mechanisms of L. coreana.

METHODS

Related literature (from 1998 to 2016) was obtained and compiled via searching databases including Scopus, Web of Science, Google Scholar, CNKI and PubMed. Keywords (Litsea coreana, hawk tea, eagle tea and laoying cha) were used to select the articles.

RESULTS

Studies indicate that L. coreana contains characteristic polysaccharides, polyphenols, essential oils, and numerious flavonoids, which exhibit remarkable bioactivities, such as hepatoprotection, hyperglycaemia, anti-inflammation, antioxidation and antibacterial, through multiple molecular mechanisms.

CONCLUSION

This paper provides a systematic review on the phytochemicals and pharmacological activities of L. coreana which should be useful for further study and application of this medicinal herb.

DPPH Radical Scavenging and Postprandial Hyperglycemia Inhibition Activities and Flavonoid Composition Analysis of Hawk Tea by UPLC-DAD and UPLC-Q/TOF MSE

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.

Ethnobotany, phytochemistry, and pharmacology of the genus Litsea: An update

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Litsea is one of the most diverse genera of evergreen trees or shrubs belong to Lauraceae, and comprises roughly 400 species of tree that are distributed abundantly throughout tropical and subtropical Asia, North and South America. Litsea species have been used globally in traditional medicine for the treatment of various diseases including influenza, stomach aches, diarrhea, diabetes, vomiting, bone pain, inflammation, illness related to the central nervous system and other ailments. The purpose of this review is to provide updated, comprehensive and categorized information on the ethnobotany, phytochemistry and pharmacological research of Litsea species in order to explore their therapeutic potential and evaluate future research opportunities.

MATERIALS AND METHODS

All the available information on Litsea species was actualised by systematically searching the scientific literatures including Chinese, Korean, Japanese, Indian, and South American herbal classics, library catalogs and scientific databases (PubMed, SciFinder, Web of Science, Google Scholar, VIP and Wanfang). The Plant List, International Plant Name index and Scientific Database of China Plant Species were used to validate scientific names.

RESULTS

407 secondary metabolites have been reported from Litsea species. Litsea Species are sources of secondary metabolites with interesting chemical structures (alkaloids, lactones, sesquiterpenes, flavonoids, lignans, and essential oils) and significant bioactivities. Crude extracts, fractions and phytochemical constituents isolated from Litsea show a wide spectrum of in vitro and in vivo pharmacological activities including anticancer, anti-inflammatory, antimicrobial, antioxidant, antidiabetic, anti-HIV, insecticidal, etc.

CONCLUSIONS

From data collected in this review, the genus Litsea comprises a wide range of therapeutically promising and valuable plants, and has attracted much attention owing to its multiple functions. Many traditional uses of Litsea species have now been validated by modern pharmacology research. Deep and systematic phytochemical investigation of the genus Litsea and the pharmacological properties, especially its mechanism of action and toxicology, to illustrate its ethnomedicinal use, explore the therapeutic potential and support further health-care product development will undoubtedly be the focus of further research. Therefore, detailed and extensive studies and clinical evaluation of Litsea species should be carried out in future for the safety approval of therapeutic applications.

Ultrasound-Assisted Extraction, Antioxidant and Anticancer Activities of the Polysaccharides from Rhynchosia minima Root

Box-Behnken design (BBD), one of the most common response surface methodology (RSM) methods, was used to optimize the experimental conditions for ultrasound-assisted extraction of polysaccharides from Rhynchosia minima root (PRM). The antioxidant abilities and anticancer activity of purified polysaccharide fractions were also measured. The results showed that optimal extraction parameters were as follows: ultrasound exposure time, 21 min; ratio of water to material, 46 mL/g; ultrasound extraction temperature, 63 °C. Under these conditions, the maximum yield of PRM was 16.95% ± 0.07%. Furthermore, the main monosaccharides of purified fractions were Ara and Gal. PRM3 and PRM5 exhibited remarkable DPPH radical scavenging activities and reducing power in vitro. PRM3 showed strong inhibitory activities on the growth of MCF-7 cells in vitro. The above results indicate that polysaccharides from R. minima root have the potential to be developed as natural antioxidants and anticancer ingredients for the food and pharmaceutical industries.

3-Amidocoumarins as Potential Multifunctional Agents against Neurodegenerative Diseases

Monoamine oxidase (MAO) generates reactive oxygen species (ROS), which cause neuronal cell death, causing neurodegeneration. Agents that are able to concurrently inhibit MAO and scavenge free radicals represent promising multifunctional neuroprotective agents that could be used to delay or slow the progression of neurodegenerative diseases. In this work, variously substituted 3-amidocoumarins are described that exert neuroprotection in vitro against hydrogen peroxide in rat cortical neurons, as well as antioxidant activity in a 1,1-diphenyl-2-picrylhydrazyl (DPPH⋅) radical scavenging assay. Selective and reversible inhibitors of the MAO-B isoform were identified. Interestingly, in the case of the 3-benzamidocoumarins, substitution at position 4 with a hydroxy group abolishes MAO-B activity, but the compounds remain active in the neuroprotection model. Further evaluation of 3-heteroarylamide derivatives indicates that it is the nature of the heterocycle that determines the neuroprotective effects. Evaluation in a parallel artificial membrane permeability assay (PAMPA) highlighted the need to further improve the blood-brain barrier permeability of this compound class. However, the compounds described herein adhere to Lipinski's rule of five, suggesting that this novel scaffold has desirable properties for the development of potential drug candidates.

Raspberry pulp polysaccharides inhibit tumor growth via immunopotentiation and enhance docetaxel chemotherapy against malignant melanoma in vivo

It has been reported previously that the systemic efficacy of chemotherapeutic agents is substantially restricted for some cancer types, including malignant melanoma. Therefore, the development of more effective treatment modalities remains a critical, albeit elusive, goal in anticancer therapy. The study presented here evaluates the antitumor activity of raspberry pulp polysaccharides (RPPs) against malignant melanoma using a murine tumor-bearing model. Furthermore, the underlying mechanism of this antitumor activity has also been investigated. The results show that while RPP exhibits no direct cytotoxic effect on HT-29, MGC-803, HeLa, Bel-7402, L02 and B16F10 cells in vitro, it does demonstrate a dose-dependent growth inhibition of melanoma in vivo with an inhibition ratio of 59.95% at a dose of 400 mg kg(-1). Besides this, the body weight and spleen index in tumor-bearing mice have also been improved in RPP-treated groups. RPP is also found to induce splenocyte proliferation and is able to upregulate the activity of immune-related enzymes, including acid phosphatase (ACP), alkaline phosphatase (AKP), lactate dehydrogenase (LDH) and superoxide dismutase (SOD) in the spleen of tumor-bearing mice. The levels of tumor necrosis factor α (TNF-α), interferon γ (IFN-γ) and interleukin 2 (IL-2) in the serum of tumor-bearing mice show to be effectively increased upon RPP treatment. Histopathological analyses show that RPP induces tumor tissue necrosis by increasing inflammatory cell infiltration and causes no lesions to liver and kidney tissues. Remarkably, RPP further enhances the antitumor effect of the chemotherapeutic drug docetaxel and alleviates docetaxel-induced liver and kidney lesions in tumor-bearing mice. These findings indicate that RPP exhibits antitumor activity in vivo against malignant melanoma, partly by enhancing the cellular immune response of the host organism. In summary, RPP features critical properties to potentially find use as an immunopotentiating agent or as a chemotherapy adjuvant agent for the treatment of malignant melanoma.

Antioxidant and antimicrobial properties of Litsea elliptica Blume and Litsea resinosa Blume (Lauraceae)

OBJECTIVE

To investigate antioxidant and antimicrobial activities of two plant species, Litsea elliptica (L. elliptica) and Litsea resinosa (L. resinosa).

METHODS

In vitro method-2,2-diphenyl-1-picrylhydrazyl radical scavenging assay was conducted for antioxidant activity determination while antimicrobial assay consisted of agar well diffusion assay and mycelial radial growth assay.

RESULTS

Methanol extracts of root and stem of L. elliptica and L. resinosa exhibited the highest antioxidant activity with EC50 of 23.99, 41.69, 11.22 and 35.48 mg/L respectively. All methanol extracts of L. resinosa as well as root extracts from L. elliptica showed significant scavenging activity. Hexane extract from stem of L. resinosa presented the largest inhibition zone in Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli while chloroform extract from inner bark of L. resinosa showed major inhibition towards Gram-positive bacteria Bacillus subtilis. Essential oils from the root of both species showed significant antifungal activities which are 80.11% and 66.85% respectively.

CONCLUSIONS

Overall, methanol extracts from root and stem of both species showed antioxidant activity comparable to standard butylated hydroxytoluene. Extracts from L. resinosa demonstrated stronger antimicrobial properties compared to that from L. elliptica.

Comparative studies on bioactive constituents in hawk tea infusions with different maturity degree and their antioxidant activities

Hawk tea (Litsea coreana var. lanuginose) is a very popular herbal tea in the southwest of China. According to the maturity degree of raw materials, Hawk tea can usually be divided into three types: Hawk bud tea (HB), Hawk primary leaf tea (HP), and Hawk mature leaf tea (HM). In this study, some of the bioactive constituents and antioxidant properties of the three kinds of Hawk tea infusions were comparatively investigated. The results showed that the contents of total flavonoids, vitamin C, and carbohydrates in Hawk bud tea infusion (HBI) were higher than those in Hawk primary leaf tea infusion (HPI) and Hawk mature leaf tea infusion (HMI). HPI had higher contents of total polyphenols and exhibited better DPPH radical scavenging activity and ferric reducing activity power. HBI could provide more effective protection against erythrocyte hemolysis. As age is going from bud to mature leaf, the ability to inhibit the formation of low density lipoprotein (LDL) conjugated diene and the loss of tryptophan fluorescence decreased. The bioactive constituents and antioxidant activities of Hawk tea infusions were significantly affected by the maturity degree of the raw material.

Artificial neural network optimization of Althaea rosea seeds polysaccharides and its antioxidant activity

A combination of an orthogonal L16(4)4 test design and a three-layer artificial neural network (ANN) model was applied to optimize polysaccharides from Althaea rosea seeds extracted by hot water method. The highest optimal experimental yield of A. rosea seed polysaccharides (ARSPs) of 59.85 mg/g was obtained using three extraction numbers, 113 min extraction time, 60.0% ethanol concentration, and 1:41 solid-liquid ratio. Under these optimized conditions, the ARSP experimental yield was very close to the predicted yield of 60.07 mg/g and was higher than the orthogonal test results (40.86 mg/g). Structural characterizations were conducted using physicochemical property and FTIR analysis. In addition, the study of ARSP antioxidant activity demonstrated that polysaccharides exhibited high superoxide dismutase activity, strong reducing power, and positive scavenging activity on superoxide anion, hydroxyl radical, 2,2-diphenyl-1-picrylhydrazyl, and reducing power. Our results indicated that ANNs were efficient quantitative tools for predicting the total ARSP content.