Moisture content of tea dhool for the scenting process affects the aroma quality and volatile compounds of osmanthus black tea.

To improve the quality of osmanthus black tea, samples produced with different scenting methods were prepared. The sensory quality was assessed and the characteristic aromatic components were explored using solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry. According to the results, osmanthus black tea obtained by adding osmanthus scenting in the fermentation process had the strongest floral aroma. The major contributors to the aroma of osmanthus black tea were identified as ß-ionone, dihydro-ß-ionone, benzeneacetaldehyde, citral, geraniol, and linalool by calculating their relative odor activity values. An analysis of the causes revealed that the moisture content of tea dhool significantly affected the adsorption of fresh flower aroma by tea. The experimental results showed that osmanthus black tea produced using tea dhool containing 30% moisture content had the highest content of crucial aroma components, suggesting the tea dhool under this condition had the strongest adsorption capacity for osmanthus aroma.

Enhanced Antiarthritic Efficacy by Nanoparticles of (-)-Epigallocatechin Gallate-Glucosamine-Casein.

This work aims to improve the antiarthritic activity of (-)-epigallocatechin gallate (EGCG) and glucosamine (GA) through fabrication and optimization of casein protein nanoparticles (EGC-NPs). Optimized EGC-NPs were obtained with a EGCG/GA/casein ratio of 1:2:8 (w/w/w). The EGC-NPs gave a mean size of 186 ± 3.5 nm and an entrapment efficiency of 86.8 ± 2.7%, and they exhibited a greater inhibitory activity against human fibroblast-like synoviocytes-osteoarthritis cells and human fibroblast-like synoviocytes-rheumatoid arthritis cells compared with that of the EGCG-GA mixture by 33.5% and 20.8%, respectively. Freeze-dried EGC-NPs stored at 25 °C during 12 months showed high dispersion stability. Moreover, the redispersion of the freeze-dried EGC-NPs produced almost no significant changes in their physicochemical properties and bioactivity. Rat experiments demonstrated that the antiarthritis effect of the EGC-NPs was significantly higher than that of EGCG-GA mixture, as assessed through an analysis of anti-inflammatory efficacy, radiographic images and histopathological assessments of paw joints, and immunohistochemical changes in serum cytokines. The enchanced antiarthritic activity in vivo was consistent with that in vitro. The EGC-NPs demonstrate potential as a food supplement for the treatment of arthritis.

Castanopsis lamontii Water Extract Shows Potential in Suppressing Pathogens, Lipopolysaccharide-Induced Inflammation and Oxidative Stress-Induced Cell Injury.

Castanopsis lamontii is traditionally used to prevent inflammatory diseases such as periodontitis and pharyngitis by residents in southwest China. However, little scientific evidence has been found to support this. In this research, the antibacterial activities of Castanopsis lamontii water extract (CLE) were assessed using the micro-dilution method. The anti-inflammatory and antioxidant activities of CLE were investigated in RAW264.7 cells. Key bioactive compounds in CLE were also explored. Results showed that CLE was capable of inhibiting the periodontitis pathogen Porphyromonas gingivalis and the pharyngitis pathogen ß-hemolytic Streptococcus. It suppressed lipopolysaccharide-induced inflammation in RAW 264.7 cells via inactivating the TLR4/NF-κB pathway. Besides, it reduced oxidative stress-induced cell injury via scavenging reactive oxygen species. Chemical composition analysis revealed that CLE was rich in epicatechin and procyanidin B2. Further studies confirmed that epicatechin predominantly contributed to the antibacterial activities of CLE, while procyanidin B2 was mainly responsible for the anti-inflammatory activities of CLE. Both compounds contributed to the antioxidant activities of CLE. Acute oral toxicity tests proved that CLE was practically non-toxic. These results provide experimental evidences of the health-beneficial effects of CLE and may help promote the application of CLE in the food and health industries.

Improving the taste of autumn green tea with tannase.

Green tea processed from autumn leaves is more bitter and astringent than that from spring leaves, mainly due to gallated catechins. The present study aimed to improve the taste of autumn green tea and green tea infusion by using tannase to treat tea leaves and tea infusion. The results showed that, after hydrolysis, the sweet aftertaste and overall acceptability improved, and the ratio of gallated catechins decreased, as did the bitterness and astringency of the autumn green tea. The pH value was significantly correlated with the concentrations of gallated catechins (r = 0.930, p < 0.01), non-gallated catechins (r = -0.893, p < 0.01), and gallic acid (r = 0.915, p < 0.01), as well as with the intensities of bitterness, astringency, and sweet aftertaste during hydrolysis. Gallic acid contributed to the sweet aftertaste of green tea infusion. These results will help to improve autumn green tea products with tannase.

Evaluation of Anti-Obesity Activity, Acute Toxicity, and Subacute Toxicity of Probiotic Dark Tea.

: Probiotic dark tea (PDT) is a novel kind of dark tea produced by fresh albino tea leaves and fermented with specific probiotics. Our study demonstrates that PDT can ameliorate high-fat diet-induced overweight and lipid metabolic disorders and shows no acute or subacute toxicity in Sprague-Dawley (SD) rats. Daily intragastric administration of 5% PDT infusion for 14 days caused no obvious effect on general physiological features and behaviors of rats. Oral administration of 1%, 2%, and 3% of PDT infusion for six weeks had no influence on the biochemistry and histopathology of rats' organs and blood, as well as the body weight and ratios of organ/body weight. To investigate its anti-obesity activity, SD rats were randomly divided into four groups, treated with normal diet + water (Group I), high-fat diet + water (Group II), high-fat diet + 3% traditional dark tea infusion (Group III), high-fat diet + 3% PDT infusion (Group IV). After six weeks, the body weight, serum total triacylglycerol (TG) and serum total cholesterol (TC) levels of rats in Group II were significantly increased and the high-density lipoprotein cholesterol (HDL) levels were significantly decreased compared with those in the other three groups. Both traditional dark tea and PDT treatment effectively counteracted the adverse effect of a high-fat diet in SD rats. These results suggest that PDT could be applied for the prevention of obesity, which ameliorates overweight and lipid metabolic disorders and which shows no acute or subacute toxicity.

Quantitative analyses of the bitterness and astringency of catechins from green tea.

Bitterness and astringency are two important quality attributes of green tea infusion, and catechins are the main contributor to the bitterness and astringency. The aim of this work was to quantitatively analyse the bitterness and astringency of green tea infusion according to the concentrations of catechins. The concentration-taste curves of catechins showed a pattern that fit the cubic functions, and their R2 values were higher than 0.956. The bitterness of green tea was highly correlated with the concentrations of (-)-epigallocatechin gallate and (-)-epicatechin gallate (ECG) (R2 = 0.7769, p < 0.01), and the astringency (R2 = 0.7878, p < 0.01) was highly correlated with the concentrations of ECG and flavonol glycosides (myricetin 3-O-galactoside and quercetin-3-O-rutinoside). Taste interactions between different catechins and between catechins and other substances were determined. These results may enhance the understanding of tea chemistry for improving the taste of products from green tea.

Isolation and Structure Characterization of Cytotoxic Phorbol Esters from the Seeds of Croton tiglium.

Nine new and eleven known phorbol esters were isolated from an acetone extract of the seeds of Croton tiglium. Their structures were determined by extensive analysis of spectroscopic data. Eleven of these compounds were evaluated for their inhibition activity on human tumor cell lines HL-60 and lung carcinoma A549. 12-O-Tiglylphorbol-13-acetate (11), 12-O-(2-methyl)-butyrylphorbol-13-aetate (12), and 12-O-tiglylphorbol-13-isobutyrate (13) exhibited strong inhibition activity against both HL-60 and A549 cell lines with IC50 values ≤ 0.02 and ≤ 0.1 µg/mL, respectively. Compound 18 showed strong inhibition activity against the HL-60 cell line with an IC50 value of 0.02 µg/mL.

Sucrose esters improve the colloidal stability of nanoethosomal suspensions of (-)-epigallocatechin gallate for enhancing the effectiveness against UVB-induced skin damage.

Nanoethosomal suspensions, composed of phospholipids, ethanol, and water, are novel lipid carriers. These suspensions have been reported to enhance the permeation of drugs into the skin as a result of the interdigitation effect of ethanol on the lipid bilayer of liposomes and by increasing the fluidity of lipids in the stratum corneum. The physical stability of the nanoethosomal suspension is still a critical research problem until now. This study investigated the commercial palm sucrose esters to improve the colloidal stability of nanoethosomal suspensions. The results indicated that palm sucrose esters (PSE) were effective for stabilizing nanoethosomal suspension of (-)-epigallocatechin gallate (EGCG) from green tea. A PSE concentration of 0.15% was optimal for a nanoethosomal suspension which gave mean diameter 75.5 ± 3.5 nm, zeta potential -30.8 ± 3.2 mV and polydispersity index 0.207 ± 0.017. Moreover, the effectiveness of stabilization was influenced by the degree of esterification of the sucrose esters: the sucrose polyesters could prolong the stability of nanoethosomes loaded with EGCG to a year, but the sucrose monoesters only provided less than 6 months of stabilization. EGCG nanoethosomal suspension stabilized by sucrose polyesters shows better inhibition effectiveness against UVB-induced skin damage than native EGCG. The nanoethosomal suspension has the potential for its utilization as skin care and other products. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2416-2425, 2017.

Improving the sweet aftertaste of green tea infusion with tannase.

The present study aims to improve the sweet aftertaste and overall acceptability of green tea infusion by hydrolyzing (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG) with tannase. The results showed that the intensity of the sweet aftertaste and the score of overall acceptability of the green tea infusion significantly increased with the extension of the hydrolyzing treatment. (-)-Epigallocatechin (EGC) and (-)-epicatechin (EC) were found to be the main contributors for the sweet aftertaste, based on a trial compatibility with EGCG, ECG, EGC, and EC monomers, and a synergistic action between EGC and EC to sweet aftertaste was observed. A 2.5:1 (EGC/EC) ratio with a total concentration of 3.5 mmol/L gave the most satisfying sweet aftertaste, and the astringency significantly inhibited the development of the sweet aftertaste. These results can help us to produce a tea beverage with excellent sweet aftertaste by hydrolyzing the green tea infusion with tannase.

The major factors influencing the formation of sediments in reconstituted green tea infusion.

The effects of Ca(2+), caffeine and polyphenols on the formation of reversible tea sediments (RTS) and irreversible tea sediments (IRS) in green tea infusion were studied. Adding Ca(2+) (2 mmol/l) was found to increase the formation of RTS by 8% and IRS by 92%, while adding chelating ions of Na2EDTA significantly decreased the amount of RTS by 14.6%, but not the amount of IRS. Under acid conditions, Ca(2+) combined with oxalic ions to form indissoluble oxalate that is the principal constituent of IRS, despite the existence of the chelating ions. Decaffeination largely inhibited the formation of RTS (73%) and IRS (60%), even in the presence of Ca(2+). The amount of sediment could be reduced by removing polyphenols using polyvinyl-polypyrrolidone. The results suggest that sediment formation in green tea infusions can be inhibited by lowering the concentration of Ca(2+), caffeine or polyphenols.

Ethyl acetate-n-butanol gradient solvent system for high-speed countercurrent chromatography to screen bioactive substances in okra.

High-speed countercurrent chromatographic separation (HSCCC) possesses the property of zero-loss of sample, which is very useful for the screening of bioactive components. In the present study, the ethyl acetate-n-butanol gradient HSCCC solvent system composed of n-hexane-ethyl acetate-n-butanol-water was investigated for the screening of bioactive substances. To screen the antiproliferative compounds in okra extract, we used the stationary phase ethyl acetate-n-butanol-water (1:1:10) as the stationary phase, and eluted the antiproliferative components by 6-steps of gradient using mobile phases n-hexane-ethyl acetate (1:2), n-hexane-ethyl acetate (1:4), n-hexane-ethyl acetate (0:4), n-butanol-ethyl acetate (1:4) n-butanol-ethyl acetate (1:2), n-butanol-ethyl acetate (2:2), and n-butanol-ethyl acetate (2:1). The fractions collected from HSCCC separation with the gradient solvent system were assayed for antiproliferative activity against cancer cells. Bioactive components were identified: a major anti-cancer compound, 4'-hydroxy phenethyl trans-ferulate, with middle activity, and a minor anti-cancer compound, carolignan, with strong activity. The result shows that the gradient solvent system is potential for the screening of bioactive compounds from natural products.

Sediments in concentrated green tea during low-temperature storage.

The formation and the main chemical components of sediments, including reversible tea sediments (RTS) and irreversible tea sediments (IRS), in concentrated green tea during low-temperature storage were studied. RTS was mainly formed in the first 10 days, and IRS was mainly formed between 20 and 40 days of storage. The RTS were the primary sediment, contributing more than 90% of the total sediment. The RTS comprised of polyphenols, total sugar, caffeine, flavones and proteins, while the IRS mainly comprised of oxalates of Ca, Mg, Ga and Mn. The total mineral content in the IRS (17.1%) was much higher than that in the RTS (2.6%) after 80 days of storage. The Ca, Mg, Mn and Ga contents in IRS were over 1.0% (w/w) each. About 75% of the IRS was soluble in 0.1 M aqueous HCl, with the oxalate accounting for 68%. Minerals and oxalic acid were the crucial factors in the IRS formation.

The impact of Ca2+ combination with organic acids on green tea infusions.

The effect of Ca(2+) in brewing water on the organic acid content, turbidity, and formation of tea cream and sediment in green tea infusions was studied. When the Ca(2+) concentration of the brewing water was >40 mg L(-1), the green tea infusion became more turbid. The turbidity of the tea infusion was highly negatively correlated with the contents of oxalic acid (R=-0.89, p<0.01), quinic acid (R=-0.90, p<0.01) and tartaric acid (R=-0.82, p<0.01). Oxalic acid on its own interacted with Ca(2+) at low concentrations, whereas polyphenols and protein did not. In conclusion, Ca(2+) in brewing water influences the quality of a tea infusion by inducing tea cream and sediment formation from combination of Ca(2+) and organic acids, such as oxalic acid, quinic acid and tartaric acid. Ca(2+) and oxalate are the main metal ion and anion, respectively, involved in tea cream and sediment formation on tea infusion cooling or concentrating.

Scaling up of high-speed countercurrent chromatographic apparatus with three columns connected in series for rapid preparation of (-)-epicatechin.

In the present study, compact high-speed countercurrent chromatographic apparatus was constructed with three columns connected in series. Two sets of columns were prepared from 10 mm and 12 mm I.D. tubing to form 12 L and 15 L capacities, respectively. Performance of these columns was compared for the separation of (-)-epicatechin gallate (ECG) from a tea extract by flash countercurrent chromatography (FCCC). In each separation, 200 g of the tea extract in 1600 mL of mobile phase was loaded onto the column. The 12 L column gave 7.5 L (35 g of ECG) and the 15 L column gave 9 L (40 g of ECG) of ECG solution without impurities. The ECG solution was directly hydrolyzed by tannase into (-)-epicatechin. The hydrolysate was purified by flash chromatography on AB-8 macroporous resin to give 52 g of EC (purity 99.1%). This scaled up apparatus could be used for the industrial separation of natural products.

[Determination of active components in silymarin by UPLC-ESIMS].

A UPLC-ESIMS method was developed for simultaneous analysis of seven major bioactive flavonolignans in silymarin including silychristins A(1) and B(2), silydianin(3), silybins A(4) and B(5), and isosilybins A(6) and B(7). In this study, the seven major active flavonolignans including the diastereomers 1/2, 4/5, and 6/7 were completely separated using UPLC with an ACQUITY UPLC C18 column and MeOH-water (formic acid) mobile phase system. The collision-induced dissociation (CID) MS/MS spectra of these flavonolignans were studied systematically using ESI-MS. The results with the present methodology showed that UPLC-MS/MS can be used for general screening of active natural products from plant extracts and for the specific quality control of silymarin.

[Preparation of crocin from gardenia yellow pigment by slow rotary countercurrent chromatography].

A method was established for the preparation of crocin from gardenia yellow pigment by slow rotary countercurrent chromatography (SRCCC). A two-phase solvent system consisting of methyl tert-butyl ether, n-butanol, acetonitrile and water (2 : 2. 5 : 1 : 5, v/v/v/v) was used. The upper phase was used as the stationary phase, and the lower phase as the mobile phase. By SRCCC elution, 2.47 g of crocin with a purity of 96.8% was obtained from 5 g of gardenia yellow pigment at a flow rate of 5 mL/min and a rotation speed of 50 r/min. The results indicated that SRCCC is a powerful technique for the purification of crocin from gardenia yellow pigment with high preparative capacity, high safety and high efficiency in resolution, and it is possible to prepare crocin at industrial level by SRCCC.

Bioactive diterpenes from Clerodendrum kaichianum.

Bioassay-guided isolation studies of the extract of Clerodendrum kaichianum Hsu., a new rearranged abietane diterpene and five known diterpene compounds were isolated by various chromatography methods. Their structures were identified by means of spectroscopic methods, including 1D- and 2D-NMR spectroscopy, as (16R)-12,16-epoxy-11,14,17-trihydroxy-17(15-->16)-abeo-8,11,13-abietatrien-7-one (1), villosin A (2), salvinolone (3), 14-deoxyloleon U (4), 5,6-dehydrosugiol (5), and coleon U (6). Compounds 1, 2, 3, and 5 are reported for the first time for this genus. Compounds 1, 2, and 6 demonstrated potent cytotoxic activities against the HL-60 tumor cell line.

A new rearranged abietane diterpenoid from Clerodendrum kaichianum Hsu.

A new abietane diterpenoid, (3S,16R)-12,16-epoxy-3,6,11,14,17-pentahydroxy-17(15 â†’ 16)-abeo-5,8,11,13-abietatetraen-7-one (1), was isolated from the stems of Clerodendrum kaichianum Hsu, together with four known diterpenoids. The structures of the isolated compounds were assigned on the basis of their NMR spectra including 2D NMR techniques such as COSY, HMQC, and HMBC experiments, and were compared with those of the literature data. This new compound showed significant cytotoxicity against the HL-60 and A-549 tumor cell lines.

Preparation of the monomers of gingerols and 6-shogaol by flash high speed counter-current chromatography.

The flash high speed counter-current chromatographic (FHSCCC) separation of gingerols and 6-shogaol was performed on a HSCCC instrument equipped with a 1200-ml column (5 mm tubing i.d.) at a flow rate of 25 ml/min. The performance met the FHSCCC feature that the flow rate of mobile phase (ml) is equal to or greater than the square of the diameter of the column tubing (mm). The separation employed the upper phase of stationary phase of the n-hexane-ethyl acetate-methanol-water (3:2:2:3, v/v) as the stationary phase. A stepwise elution was performed by eluting with the lower phase of n-hexane-ethyl acetate-methanol-water (3:2:2:3, v/v) for first 90 min and the lower phase of the n-hexane-ethyl acetate-methanol-water (3:2:6:5, v/v) for the second 90 min. In each separation 5 g of the ethyl acetate extract of rhizomes of ginger was loaded, yielding 1.96 g of 6-gingerol (98.3%), 0.33 g of 8-gingerol (97.8%), 0.64 g of 6-shogaol (98.8%) and 0.57 g of 10-gingerol (98.2%). The separation can be expected to scale up to industrial separation.

Rapid separation and characterization of active flavonolignans of Silybum marianum by ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry.

Ultra-performance liquid chromatography (UPLC) interfaced with the electrospray ionization (ESI) tandem mass spectrometer (MS(n)) was developed for the simultaneous determination of silychristins A (1) and B (2), silydianin (3), silybins A (4) and B (5), and isosilybins A (6) and B (7), major bioactive flavonolignans in silymarin, a herbal remedy derived from the milk thistle Silybum marianum. In this study, the seven major active flavonolignans including the diastereomers 1/2, 4/5, and 6/7 were completely separated using UPLC with an ACQUITY UPLC C(18) column and a MeOH/water/formic acid mobile phase system. The collision-induced dissociation (CID) MS(n) spectra of these flavonolignans were studied systematically using ESI-MS. The results with the present methodology show that UPLC-MS(n) can be useful for general screening of active natural products from plant extracts and for the specific quality control of silymarin.