Quantitative and fingerprint analyses of Chinese sweet tea plant ( Rubus suavissimus S. Lee)

Novel α-glycosyl compounds from glycosylation of rubusoside

In this work we investigated mixtures from α-glycosylation of rubusoside with cyclodextrin glycosyltransferases. In addition to the previously known α-1,4 glycosylated derivatives, nine new compounds with rare α-1,3-glycosidic bonds were identified based on nuclear magnetic resonance spectroscopy and mass spectrometric analysis. Furthermore, sensory properties of monoglycosylated rubusoside derivatives were investigated and compared to previously described monoglycosylated compounds. Additionally, digestion with α-amylase from human saliva was investigated for different glycosylated rubusoside derivatives.

The effect of sweet tea polysaccharide on the physicochemical and structural properties of whey protein isolate gels

In this study, we investigated the effect of sweet tea polysaccharide (STP) on the physicochemical and structural properties of heat-induced whey protein isolate (WPI) gels, and explored the potential mechanism. The results indicated that STP promoted the unfolding and cross-linking of WPI to form a stable three-dimensional network structure, and significantly improved the strength, water-holding capacity and viscoelasticity of WPI gels. However, the addition of STP was limited to 2 %, too much STP would loosen the gel network and affect the gel properties. The results of FTIR and fluorescence spectroscopy suggested that STP affected the secondary and tertiary structures of WPI, promoted the movement of aromatic amino acids to the protein surface and the conversion of α-helix to β-sheet. In addition, STP reduced the surface hydrophobicity of the gel, increased the free sulfhydryl content, and enhanced the hydrogen bonding, disulfide bonding, and hydrophobic interactions between protein molecules. These findings can provide a reference for the application of STP as a gel modifier in the food industry.

Catalyzing systemic movement of inward rectifier potassium channel inhibitors for antifeedant activity against the cotton aphid, Aphis gossypii (Glover)

BACKGROUND

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a destructive agricultural pest, capable of photosynthate removal and plant virus transmission. Therefore, we aimed to test the antifeedant properties of small-molecule inhibitors of inward rectifier potassium (Kir) channels expressed in insect salivary glands and develop an approach for enabling systemic movement of lipophilic Kir inhibitors.

RESULTS

Two Kir channel inhibitors, VU041 and VU730, reduced the secretory activity of the aphid salivary glands by 3.3-fold and foliar applications of VU041 and VU730 significantly (P < 0.05) increased the time to first probe, total probe duration, and nearly eliminated phloem salivation and ingestion. Next, we aimed to facilitate systemic movement of VU041 and VU730 through evaluation of a novel natural product based solubilizer containing rubusoside that was isolated from Chinese sweet leaf (Rubus suavissimus) plants. A single lower leaf was treated with Kir inhibitor soluble liquid (KI-SL) and systemic movement throughout the plant was verified via toxicity bioassays and changes to feeding behavior through the electrical penetration graph (EPG) technique. EPG data indicate KI-SL significantly reduced ability to reach E1 (phloem salivation) and E2 (phloem ingestion) waveforms and altered plant probing behavior when compared to the untreated control. High-performance liquid chromatography (HPLC) analysis indicated the presence of VU041 and VU730 in the upper leaf tissue of these plants. Together, these data provide strong support that incorporation of rubusoside with Kir inhibitors enhanced translaminar and translocation movement through the plant tissue.

CONCLUSION

These data further support hemipteran Kir channels as a target to prevent feeding and induce toxicity. Further, these studies highlight a novel delivery approach for generating plant systemic activity of lipophilic insecticides. © 2022 Society of Chemical Industry.

Sweet tea (Rubus Suavissmus S. Lee) polysaccharides promote the longevity of Caenorhabditis elegans through autophagy-dependent insulin and mitochondrial pathways

The fine structure of sweet tea polysaccharide (STP-60a) has been characterized. However, the biological activity of STP-60a has not been extensively explored. This study aims to evaluate the anti-aging activity of STP-60a using Caenorhabditis elegans (C. elegans) as a model and to investigate the underlying molecular mechanism. 400 μg/mL of STP-60a increased the mean lifespan of C. elegans by 22.88%, reduced the lipofuscin content by 33.01%, and improved the survival rate under heat stress and oxidative stress by 32.33% and 27.63%, respectively. Further research in lifespan-related mutants revealed that STP-60a exerted anti-aging effects mainly through insulin and mitochondrial signaling pathways. Through qRT-PCR and microscopic imaging of transgenic nematodes, we found that 400 μg/mL of STP-60a increased the expression of daf-16, skn-1, and hsf-1 downstream of the insulin pathway by 1.68-fold, 1.88-fold, and 1.03-fold, respectively, and promoted the accumulation of daf-16 and skn-1 in the nucleus. STP-60a also significantly regulated the function of the mitochondrial respiratory chain and unfolded protein recovery system. Furthermore, STP-60a activated the autophagy level in C. elegans, and the mutation of daf-2 or clk-1 inhibited the upregulation of autophagy genes by STP-60a, suggesting that autophagy acted as an effector of the insulin and mitochondrial pathways during STP-60a antiaging.

Structure characterization and lipid-lowering activity of a homogeneous heteropolysaccharide from sweet tea (Rubus Suavissmus S. Lee)

Sweet tea (Rubus Suavissmus S. Lee) is consumed as herbal tea in southwestern China, which has multiple functions such as relieving cough, alleviating allergic responses, and clearing away heat. Here we report the structure and lipid-lowering activity of a sweet tea polysaccharide (STP-60a). STP-60a is a homogeneous heteropolysaccharide with a molecular weight of 9.16 × 10⁴ Da, and composed of rhamnose, arabinose, glucose, galactose and glucuronic acid. The main backbone of STP-60a consists of β-L-Rhap-(1→, →3)-β-D-Galp-(1→, →4)-β-D-Glcp-UA-(1→, →3,6)-β-D-Galp-(1→, →6)-β-D-Galp-(1→, →3)-4-OAc-β-L-Arap-(1→, →3)-α-L-Araf-(1→ and the side chain are α-L-Araf-(1→ and →3)-α-D-Glcp-(1→. Using Caenorhabditis elegans (C. elegans) in a high-sugar diet as a model, we found that STP-60a significantly reduced the fat accumulation in the intestine of C. elegans, and extensively affected lipolysis, fatty acid synthesis and β-oxidation processes. In addition, sbp-1 and nhr-49 were essential for STP-60a to exert a lipid-lowering effect.

A Novel β-Glucosidase From Chryseobacterium scophthalmum 1433 for Efficient Rubusoside Production From Stevioside

As a natural sweetening and solubilizing agent, rubusoside has great potential in the application of healthy beverages and pharmaceuticals. However, the direct extraction and purification of rubusoside from raw materials is inefficient. In this work, a novel β-glucosidase (CsBGL) was obtained from Chryseobacterium scophthalmum 1433 through screening of the environmental microorganisms. CsBGL markedly hydrolyzed sophorese (Glcβ1-2Glc) and laminaribiose (Glcβ1-3Glc), but for steviol glycosides, it only hydrolyzed the C-13/C-19-linked sophorese, instead of the C-13/C-19-linked Glcβ1-2[Glcβ1-3]Glc trisaccharide and Glcβ1-monosaccharide. It efficiently hydrolyzed stevioside (240 g/L) to produce rubusoside (99% yield) at 47.5°C for 70 min. Even when using a crude steviol glycosides extract (500 g/L) containing ∼226 g/L stevioside as the substrate, CsBGL could also convert stevioside to rubusoside (99% yield) at 47.5°C for 2 h, in which the rubusoside concentration increased from the initial 42 g/L to the final 222 g/L. These results reveal that CsBGL would be a promising biocatalyst for the industry-scale production of rubusoside from stevioside or/and the crude steviol glycosides extract.

1H NMR-based urinary metabonomic study of the antidiabetic effects of Rubus Suavissimus S. Lee in STZ-induced T1DM rats

Long-term hyperglycemia associated with diabetes mellitus (DM) causes damage to various organs and tissues, including the eyes, kidneys, heart, blood vessels and nerves. Rubus Suavissimus S. Lee (RS), a shrub whose leaves are used in traditional Chinese medicine (TCM), has been shown to exert hypoglycemic effects in DM patients. However, the underlying mechanism is unclear. This was investigated in the present study in a rat model of streptozotocin-induced type 1 diabetes mellitus (T1DM) by ¹H NMR analysis. We identify 9 metabolites whose levels were altered in T1DM rats compared to control rats, namely, lactate, acetate, pyruvate, succinate, 2-oxoglutarate, citrate, creatinine, allantoin, and hippurate, which are mostly related to glycolysis/gluconeogenesis, pyruvate metabolism, TCA cycle, and other metabolism. The observed pathologic changes in the levels of these metabolites in T1DM rats were reversed by treatment with RS. Thus, RS exerts effects in T1DM rats by regulating the three abnormal metabolic pathways synergistically. These findings provide supporting evidence for the therapeutic efficacy of this TCM formulation in the treatment of DM.

Development of a Multifunction Set Yogurt Using Rubus suavissimus S. Lee (Chinese Sweet Tea) Extract

Rubus suavissimus S. Lee leaves, also known as Chinese sweet tea or Tiancha, are used in folk medicine in southern China. This study evaluated the impact of the addition of Chinese sweet tea extract (0.25%, 0.5%, and 1%) on the chemical composition, organoleptic properties, yogurt culture viability, and biological activities (i.e., antioxidant, anticancer, and antihypertensive activities) of yogurt. Seven phenolic compounds were reported in Chinese sweet tea for the first time. The numbers of the yogurt culture were similar across all yogurt treatments. The yogurt supernatant with 0.25%, 0.5%, and 1% Chinese sweet tea extract had a total phenolic content that was 3.6-, 6.1-, and 11.2-fold higher, respectively, than that of the control yogurt. The biological activities were significantly increased by the addition of Chinese sweet tea extract: Yogurt with the addition of 1% Chinese sweet tea extract had the highest biological activities in terms of the antioxidant activity (92.43%), antihypertensive activity (82.03%), and inhibition of the Caco-2 cell line (67.46%). Yogurt with the addition of 0.5% Chinese sweet tea extract received the highest aroma and overall acceptability scores. Overall, Chinese sweet tea extract is a promising food ingredient for producing functional yogurt products that may substantially contribute to reducing the risk of developing chronic diseases such as cancer and cardiovascular disease.

Chinese Sweet Leaf Tea (Rubus suavissimus) Mitigates LPS-Induced Low-Grade Chronic Inflammation and Reduces the Risk of Metabolic Disorders in a C57BL/6J Mouse Model

Chronic exposure to minute doses of endotoxin elicits intestinal inflammation and impairs the gut barrier function, potentially resulting in systemic inflammation with elevated concentrations of biomarkers associated with metabolic syndrome. This study aimed to investigate the preventive effects of the Rubus suavissimus S. Lee leaf extract in a model of low-grade systemic inflammation. The predominant compounds found in the leaf extract are gallic acids, ellagic acid, and rubusoside. Results of the present study showed that R. suavissimus leaf extract supplementation could help preserve intestinal barrier integrity by upregulating the expression of the tight junction proteins [e.g., zonula occluden-1 (ZO-1) and junctional adhesion molecule-1 (JAMA)] and mucin (MUC)-4 and also suppress the release of plasmatic proinflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and monocyte chemotactic protein (MCP)-1, while restoring the production of anti-inflammatory adiponectin. We subsequently determined that the leaf extract contributes to restoring glucose metabolic homeostasis through maintaining insulin sensitivity. Furthermore, our mechanistic finding demonstrated that the R. suavissimus leaf extract supplementation prevented systemic inflammation-driven impaired insulin sensitivity in white adipose tissues (WATs) by modulating the expression of peroxisome-proliferator-activated receptor-γ (PPAR-γ) and insulin receptor subset-1 (IRS-1). Altogether, our findings suggest that the above supplementation contributes to restoring immune and metabolic homeostasis to enhance the overall health of the host thereby preventing the early onset of metabolic disorders such as obesity and type 2 diabetes.

Histochemical assays of secretory trichomes and the structure and content of mineral nutrients in Rubus idaeus L. leaves

Leaves of Rubus idaeus are a raw material, ingredients of herbal blend, and a source of antioxidants. There are no data concerning histochemistry of trichomes, and little is known about the leaf structure of this species. The aim of this study was to determine the histochemistry of active compounds and the structure of glandular trichomes, micromorphology, anatomy, and ultrastructure of leaves as well as content of elements. To determine the histochemistry of glandular trichomes, different chemical compounds were used. The leaf structure was analysed using light, scanning, and transmission electron microscopes. The content of elements was determined with atomic absorption spectrometry, and the microanalysis of the epidermis ultrastructure was carried out with a transmission electron microscope equipped with a digital X-ray analyser. In glandular trichomes, polyphenols, terpenes, lipids, proteins, and carbohydrates were identified. The main elements in the ultrastructure of the epidermis were Na, Mo, Se, Ca, and Mg. In dry matter of leaves, K, Mg, Ca, P, and Fe were dominant. Infusions from leaves are safe for health in terms of the Cd and Pb concentrations. Leaves can be a valuable raw material. Non-glandular trichomes prevent clumping of mixed raw materials in herbal mixtures.

Gas chromatographic fingerprint analysis of secondary metabolites of Stachys lanata (Stachys byzantine C. Koch) combined with antioxidant activity modelling using multivariate chemometric methods

S. lanata has been traditionally used as a medicinal plant due to its various biological activities such as antioxidant activity. Therefore, identification and quality control studies of this plant are of great importance. To this end, gas chromatography (GC) combined with chemometrics was proposed for fingerprint analysis of S. lanata samples. This study sought to classify GC fingerprints of twenty-eight S. lanata samples from eight different regions of Iran and more importantly, to correlate fingerprints to the antioxidant activity to select S. lanata volatile antioxidant markers. S. lanata samples were classified into five and three classes using partial least squares-discriminant analysis (PLS-DA) according to their GC fingerprints and antioxidant peaks, respectively. The results of PLS regression (PLS-R) and variable importance in projection (VIP) showed that phenol, 2,4-bis (1,1-dimethylethyl)-, hexadecanoic acid- ethyl ester, vitamin E, Beta- sitosterol, and 1- monolinoleoylglycerol trimethylsily ether are volatile antioxidant markers of S. lanata samples.

Expression and characterization of a recombinant stevioside hydrolyzing β-glycosidase from Enterococcus casseliflavus

The demand for steviol glycosides, non-caloric sweet components of Stevia rebaudiana Bertoni (stevia) leaves, has increased considerably as a benefit to enhance human health. However, the supply has remained challenging due to limited production, with the lack of a specific steviol glycoside hydrolyzing enzyme. In this study, a novel β-glucosidase (EcBgl) from Enterococcus casseliflavus was cloned and expressed in Escherichia coli. An EcBgl consists of 721 amino acids corresponding to a molecular mass of 79.37 kDa. The EcBgl was purified to homogeneity, followed by enzyme characterization. The enzyme showed optimum pH and temperature at 6.0 and 37 °C, and exhibited the kinetic constants k_cat/K_m for pNPG and k_cat/K_m for stevioside of 8583 mM^-1s^-1 and 95.41 mM^-1s^-1, respectively. When compared to the stevioside hydrolyzing β-glycosidases previously reported, EcBgl was found to be the most efficient enzyme. EcBgl also rendered hydrolysis of the stevioside to produce rubusoside, a rare steviol glycoside with a pharmaceutical solubilizing property, by cleaving at the glucose moiety. In addition, the enzyme demonstrated substantial resistance against amygdalin, so it served as a potential enzyme in agricultural and pharmaceutical applications.

Metabolomics analysis of the protective effect of rubusoside on palmitic acid-induced lipotoxicity in INS-1 cells using UPLC-Q/TOF MS

Diabetes is one of the most severe chronic diseases worldwide.

Chemical Fingerprint and Multicomponent Quantitative Analysis for the Quality Evaluation of Cyclocarya paliurus Leaves by HPLC-Q-TOF-MS

Cyclocarya paliurus is an edible and medicinal plant containing various bioactive components with significant health benefits. A combinative method using high-performance liquid chromatography (HPLC) fingerprint and quantitative analysis was developed and successfully applied for characterization and quality evaluation of C. paliurus leaves collected from 18 geographical locations of China. For the fingerprint analysis, 21 common peaks were observed among the 18 samples, and these peaks were identified by high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS), while a simultaneous quantification of 16 markers was conducted to interpret the variations of contents of these bioactive compounds among the C. paliurus leaves from different geographical locations. Quantification results showed that the contents of these sixteen investigated compounds varied greatly among the leaves from different locations. The developed new method would be a valuable reference for further study and development of this bioactive plant.

Chemical Fingerprint and Multicomponent Quantitative Analysis for the Quality Evaluation of Cyclocarya paliurus Leaves by HPLC-Q-TOF-MS

Cyclocarya paliurus is an edible and medicinal plant containing various bioactive components with significant health benefits. A combinative method using high-performance liquid chromatography (HPLC) fingerprint and quantitative analysis was developed and successfully applied for characterization and quality evaluation of C. paliurus leaves collected from 18 geographical locations of China. For the fingerprint analysis, 21 common peaks were observed among the 18 samples, and these peaks were identified by high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS), while a simultaneous quantification of 16 markers was conducted to interpret the variations of contents of these bioactive compounds among the C. paliurus leaves from different geographical locations. Quantification results showed that the contents of these sixteen investigated compounds varied greatly among the leaves from different locations. The developed new method would be a valuable reference for further study and development of this bioactive plant.

Identification of Plants That Inhibit Lipid Droplet Formation in Liver Cells: Rubus suavissimus Leaf Extract Protects Mice from High-Fat Diet-Induced Fatty Liver by Directly Affecting Liver Cells

Fatty liver disease is a condition in which abnormally large numbers of lipid droplets accumulate in liver cells. Fatty liver disease induces inflammation under conditions of oxidative stress and may result in cancer. To identify plants that protect against fatty liver disease, we examined the inhibitory effects of plant extracts on lipid droplet formation in mouse hepatoma cells. A screen of 98 water extracts of plants revealed 4 extracts with inhibitory effects. One of these extracts, Rubus suavissimus S. Lee (Tien-cha or Chinese sweet tea) leaf extract, which showed strong inhibitory effects, was tested in a mouse fatty liver model. In these mouse experiments, intake of the plant extract significantly protected mice against fatty liver disease without affecting body weight gain. Our results suggest that RSE directly affects liver cells and protects them from fatty liver disease.

Cytotoxic and antiangiogenic paclitaxel solubilized and permeation-enhanced by natural product nanoparticles

Paclitaxel (PTX) is one of the most potent intravenous chemotherapeutic agents to date, yet an oral formulation has been problematic because of its low solubility and permeability. Using the recently discovered solubilizing properties of rubusoside (RUB), we investigated the unique PTX-RUB formulation. PTX was solubilized by RUB in water to levels of 1.6-6.3 mg/ml at 10-40% weight/volume. These nanomicellar PTX-RUB complexes were dried to a powder, which was subsequently reconstituted in physiologic solutions. After 2.5 h, 85-99% of PTX-RUB remained soluble in gastric fluid, whereas 79-96% remained soluble in intestinal fluid. The solubilization of PTX was mechanized by the formation of water-soluble spherical nanomicelles between PTX and RUB, with an average diameter of 6.6 nm. Compared with Taxol, PTX-RUB nanoparticles were nearly four times more permeable in Caco-2 cell monocultures. In a side-by-side comparison with dimethyl sulfoxide-solubilized PTX, PTX-RUB maintained the same level of cytotoxicity against three human cancer cell lines with IC50 values ranging from 4 to 20 nmol/l. In addition, tubule formation and migration of human umbilical vein endothelial cells were inhibited at levels as low as 5 nmol/l. These chemical and biological properties demonstrated by the PTX-RUB nanoparticles may improve oral bioavailability and enable further pharmacokinetic, toxicologic, and efficacy investigations.

Selective production of rubusoside from stevioside by using the sophorose activity of β-glucosidase from Streptomyces sp. GXT6

In order to produce rubusoside, enzymes with preferential specificity for the saccharide sophorose were tested for ability to produce rubusoside from stevioside. We identified BGL1, a β-glucosidase from Streptomyces sp. GXT6, as an enzyme for rubusoside production. Out of several saccharide substrates, BGL1 showed the most affinity to sophorose. This enzyme only hydrolyzes the glucose moiety of the sophoroside at C-13 in stevioside. Production of rubusoside was determined by (1)H and (13)C nuclear magnetic resonance (NMR). Thus, rubusoside was produced from stevioside and the stevioside conversion rate was 98.2 %. The production yield of rubusoside was 78.8 % in 6 h.

Quantitation of sweet steviol glycosides by means of a HILIC-MS/MS-SIDA approach

Meeting the rising consumer demand for natural food ingredients, steviol glycosides, the sweet principle of Stevia rebaudiana Bertoni (Bertoni), have recently been approved as food additives in the European Union. As regulatory constraints require sensitive methods to analyze the sweet-tasting steviol glycosides in foods and beverages, a HILIC-MS/MS method was developed enabling the accurate and reliable quantitation of the major steviol glycosides stevioside, rebaudiosides A-F, steviolbioside, rubusoside, and dulcoside A by using the corresponding deuterated 16,17-dihydrosteviol glycosides as suitable internal standards. This quantitation not only enables the analysis of the individual steviol glycosides in foods and beverages but also can support the optimization of breeding and postharvest downstream processing of Stevia plants to produce preferentially sweet and least bitter tasting Stevia extracts.

Steviol glycosides: chemical diversity, metabolism, and function

Steviol glycosides are a group of highly sweet diterpene glycosides discovered in only a few plant species, most notably the Paraguayan shrub Stevia rebaudiana. During the past few decades, the nutritional and pharmacological benefits of these secondary metabolites have become increasingly apparent. While these properties are now widely recognized, many aspects related to their in vivo biochemistry and metabolism and their relationship to the overall plant physiology of S. rebaudiana are not yet understood. Furthermore, the large size of the steviol glycoside pool commonly found within S. rebaudiana leaves implies a significant metabolic investment and poses questions regarding the benefits S. rebaudiana might gain from their accumulation. The current review intends to thoroughly discuss the available knowledge on these issues.

Liquid chromatography/mass spectrometry based fingerprinting analysis and mass profiling of Euterpe oleracea (açaí) dietary supplement raw materials

Chemical fingerprinting and mass profiling methods to identify biologically active compounds in botanical dietary supplements is gaining much attention in recent years. Euterpe oleracea (açaí) has been reported to be rich in health-beneficial chemical constituents. We have developed LC/MS based fingerprinting and mass profiling methods to identify fatty acids, anthocyanins and non-anthocyanin polyphenols in three processed raw materials; non-organic açaí powder (ADSR-1), raw-organic açaí powder (ADSR-2) and freeze-dried açaí powder (ADSR-3) that are used in the preparation of botanical dietary supplements. For LC/MS analysis of fatty acids and non-anthocyanin polyphenols, the açaí samples were extracted sequentially with dichloromethane followed by methanol. To study fingerprinting analysis of anthocyanins, açaí samples were extracted with acidic methanol-water. The LC separation of fatty acids, non-anthocyanin polyphenols and anthocyanins in açaí raw materials was achieved using a C18 column with a gradient mobile phase consisting of solvents A (0.1% formic acid in water), and B (0.1% formic acid in methanol). MS experiments were carried out with negative and positive mode electrospray ionization. LC/MS analysis of dichloromethane extracts of (ADSR-1), (ADSR-2) and (ADSR-3) açaí powders have shown to contain fatty acids, γ-linolenic acid, linoleic acid, palmitic acid, and oleic acid. Whereas, the fingerprinting analysis of methanol extracts of ADSR-1, ADSR-2 and ADSR-3 led to the identification of phenolic acids, anthocyanin and non-anthocyanin polyphenols. The results from our study may be useful for the authentication and quality assessment of açaí dietary supplement raw materials.

Improvement of obesity phenotype by Chinese sweet leaf tea (Rubus suavissimus) components in high-fat diet-induced obese rats

Drinking an herbal tea to lose weight is a well-liked concept. This study was designed to examine the possible improvement of obesity phenotype by a new tea represented by its purified components, gallic acid, ellagic acid, and rubusoside (GER). Male obese-prone SD rats were given low-fat diet, high-fat diet, or high-fat diet plus GER at the dose of 0.22 g/kg of body weight for 9 weeks. GER significantly reduced body weight gain by 22% compared to the high-fat diet control group with 48% less abdominal fat gain. Food intake was not affected. Blood glucose was lowered in the GER-treated group, whereas serum triglycerides and cholesterol were significantly reduced by 50%. This improved obesity phenotype may be associated with the attenuated expression of vascular endothelial growth factor in preadipocyte 3T3-L1 cells. Although other underlying, possibly multiple, mechanisms behind the improved phenotype are largely unknown, the observed improvement of multiple obesity-related parameters by the new tea warrants further investigations.

CEC of phytochemical bioactive compounds

Although there are many publications related to technological or methodological developments of CEC, few focus on the analysis of natural products, especially phytochemical bioactive compounds. This review summarized the application of CEC in the analysis of phytochemical bioactive components, including flavonoids, nucleosides, steroids, lignans, quinones and coumarins, as well as fingerprint analysis of herbs. The strategies for optimization of CEC conditions and detection were also discussed.

Purification of a water extract of Chinese sweet tea plant (Rubus suavissimus S. Lee) by alcohol precipitation

The aqueous extraction process of the leaves of Rubus suavissimus often brings in a large amount of nonactive polysaccharides as part of the constituents. To purify this water extract for potential elevated bioactivity, an alcohol precipitation (AP) consisting of gradient regimens was applied, and its resultants were examined through colorimetric and HPLC analyses. AP was effective in partitioning the aqueous crude extract into a soluble supernatant and an insoluble precipitant, and its effect varied significantly with alcohol regimens. Generally, the higher the alcohol concentration, the purer was the resultant extract. At its maximum, approximately 36% (w/w) of the crude extract, of which 23% was polysaccharides, was precipitated and removed, resulting in a purified extract consisting of over 20% bioactive marker compounds (gallic acid, ellagic acid, rutin, rubusoside, and steviol monoside). The removal of 11% polysaccharides from the crude water extract by using alcohol precipitation was complete at 70% alcohol regimen. Higher alcohol levels resulted in even purer extracts, possibly by removing some compounds of uncertain bioactivity. Alcohol precipitation is an effective way of removing polysaccharides from the water extract of the sweet tea plant and could be used as an initial simple purification tool for many water plant extracts that contain large amounts of polysaccharides.