Beneficial effects of polysaccharide-rich extracts from Apocynum venetum leaves on hypoglycemic and gut microbiota in type 2 diabetic mice.

Diabetes is one of the most concerned metabolic diseases worldwide and threaten public health. In the present work, two polysaccharide-rich extracts from Apocynum venetum leaves were extracted using distilled water and alkaline solution (0.05 M NaOH), and fully characterized. Hypoglycemic and hypolipidemic effects of two polysaccharide-rich extracts on high-fat diet and streptozocin-induced type 2 diabetic mice were investigated. Treatment of alkaline extracted polysaccharide-rich products significantly decreased the levels of fasting blood glucose, serum insulin, glycated serum protein, as well as serum lipids profiles including total cholesterol, triacylglycerols, low-density lipoprotein cholesterol, and nonesterified fatty acid. Meanwhile, the reduced glycogen contents in liver were prominently improved, and the oxidative damage were markedly ameliorated by alkaline extracted polysaccharide products in diabetic mice. Furthermore, both polysaccharide-rich extracts could reverse the gut microbiota dysbiosis in diabetic mice by increasing the abundance of genera Odoribacter, Anaeroplasma, Parasutterella, and Muribaculum; while by decreasing the abundance of genera Enterococcus, Klebsiella, and Aerococcus. This study provides new sights for exploitation of Apocynum venetum extracts as a promising anti-diabetic nutraceutical for the treatment of type 2 diabetes and metabolic syndrome.

A strategy for quality evaluation of salt-treated Apocyni Veneti Folium and discovery of efficacy-associated markers by fingerprint-activity relationship modeling.

In this study, a fingerprint-activity relationship between chemical fingerprints and hepatoprotective activity was established to evaluate the quality of salt-treated Apocyni Veneti Folium (AVF). Characteristic fingerprints of AVF samples exposed to different concentrations of salt were generated by ultrafast liquid chromatography tandem triple time-of-flight mass/mass spectrometry (UFLC-Triple TOF-MS/MS), and a similarity analysis was performed based on common characteristic peaks by hierarchical clustering analysis (HCA). Then, the hepatoprotective activity of AVF against CCl4-induced acute liver damage in mice was investigated by assessing biochemical markers and histopathology, which showed that a high dose of AVF exposed to low levels of salt stress produced a marked amelioration of hepatic damage compared with the other salt-treated AVF. Finally, fingerprint-activity relationship modeling, which was capable of discovering the bioactive markers used in the quality evaluation, was investigated by the chemical fingerprints and the hepatoprotective activities utilizing multivariate statistical analysis, gray correlation analysis (GCA) and bivariate correlation analysis (BCA). The results showed that the accumulation of polyphenols, such as flavonoids and phenolic acids, in AVF subjected to low levels of salt stress could result in the effective scavenging of free radicals. Therefore, the present study may provide a powerful strategy to holistically evaluate the quality of salt-treated AVF in combination with chemical fingerprint and bioactivity evaluation.

Apoptosis induction effect of Apocynum venetum polyphenol on human U87 glioma cells via NF-κB pathway.

Aim: Apocynum venetum polyphenol (AVP) was used in in vitro glioma cells culture to prove the growth inhibitory effect of AVP on human U87 glioma cells via NF-κB pathway. Materials & methods: The MTT assay, DAPI morphology, quantitative PCR and western blot experiments were used for determination in vitro. Results & conclusion: AVP can also induce U87 cancer cells apoptosis illustrated by DAPI morphology. AVP could enhance the mRNA and protein expression of IκB-α, TNF-α, TRAIL, caspase-3 and caspase-9 in U87 cancer cells and reduce those of NF-κBp65, cIAP-1, cIAP-2, TGF-ß2, CyclinD1, VEGF and IL-8. After ammonium pyrrolidine dithiocarbamate (PDTC) treatment, the NF-κBp65 expression was reduced in U87 cells, and AVP could raise these effects. The results of HPLC indicate that AVP mainly contains six constituents. The growth inhibitory effects of AVP on U87 glioma cells are predominantly from these natural active constituents.

Protective Effects of Apocynum venetum Against Pirarubicin-Induced Cardiotoxicity.

Pirarubicin (THP) is an anthracycline antibiotic, frequently used for the treatment of various human cancers. Unfortunately, the clinical effectiveness of THP is limited by its dose-related cardiotoxicity. Apocynum leaf extract is an extract of the dried leaves of Apocynum venetum L. (a member of the Apocynaceae family, AVLE) that has many positive effects on the cardiovascular system and is widely consumed as tea in China. In this study we established a cardiactoxicity rat model, which showed that pretreatment with AVLE attenuated THP-induced myocardial histopathological injury, electrocardiogram abnormalities, and cardiac dysfunction. AVLE also significantly reduced serum levels of malondialdehyde (MDA), brain natriuretic peptide (BNP), creatine kinase (CK-MB), cardiac troponin (CTnT), and lactate dehydrogenase (LDH); and increased serum superoxide dismutase (SOD) levels. Treatment with AVLE or dexrazoxane (DZR) resulted in an increase Cytochrome C (cytc) in the mitochondria and reduced Cytc and cleaved-caspase-3 levels (p<0.05) in cytoplasm. We also found that AVLE significantly reduced voltage-dependent anion channel 1 (VDAC1), adenosine nucleotide transporter 1 (ANT1), and cyclophilin D (CYPD) mRNA expression (p<0.05). Furthermore, AVLE appeared to exert therapeutic effects in a dose-dependent manner. Our study suggests the anti-oxidant and anti-apoptotic properties of AVLE may be responsible for the observed cardioprotective effects.

Lithium biofortification of medicinal tea Apocynum venetum.

Lithium (Li) could be much safer and successful approach to supply Li via Li-fortified food products. This study is highlighting the potential scope of Li supply via Li-biofortification of Luobuma tea (made from Apocynum venetum leaves), which is a very popular beverage in Asia with several medical properties. We explored the possibility of A. venetum as Li-enriched tea and investigated plant growth, Li accumulation, total flavonoids (TFs), rutin and hyperoside concentrations, and the antioxidant capacity of A. venetum. With the increase of additional Li, Li concentration in roots, stems and leaves increased gradually. Compared with the control treatment, 10-15 mg kg-1 Li addition stimulated the growth of A. venetum and 25 mg kg-1 Li addition significantly increased the Li concentration in leaves by 80 mg kg-1. Li application did not decrease TFs, rutin, hyperoside and antioxidant capacity of this medicinal herb. A daily consumption of 10 g Li-biofortified A. venetum leaves (cultivated with 25 mg kg-1 LiCl) can give 592 µg Li intake and would constitute 59% of the provisional recommended dietary daily intake of Li. Our results showed that Li-biofortified A. venetum leaves can be used as Li-fortified tea to enhance Li supply and to improve human health when it was used as daily drink.

Anticoagulant activity of two novel polysaccharides from flowers of Apocynum venetum L.

Two novel polysaccharides were obtained from flowers of Apocynum venetum L., and named as Vp2a-II and Vp3. Their average molecular weights were 7 kDa and 9 kDa, respectively. Methods of monosaccharide analysis, acid hydrolysis and methylation analysis, Fourier transform-infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectroscopy were used to identify the structure of Vp2a-II and Vp3. Vp2a-II was composed of →6)-ß-d-Glcp-(1 → 6)-α-d-Galp-(1→ residues. Vp3 was composed of α-d-GlcpA-(3 → α-d-GalpA residues. The anticoagulant activity was evaluated by activated partial thromboplastin time (APTT), thrombin time (TT), prothrombin time (PT), and fibrinogen (FIB) assays in vitro. Results indicated that Vp3 exhibited the anticoagulant activity.

Meroterpenoids and Isocoumarinoids from a Myrothecium Fungus Associated with Apocynum Venetum.

Four new meroterpenoids 1⁻4 and four new isocoumarinoids 5⁻8, along with five known isocoumarinoids (9⁻13), were isolated from the fungus Myrothecium sp. OUCMDZ-2784 associated with the salt-resistant medicinal plant, Apocynum venetum (Apocynaceae). Their structures were elucidated by means of spectroscopic analysis, X-ray crystallography, ECD spectra and quantum chemical calculations. Compounds 1⁻5, 7, 9 and 10 showed weak α-glucosidase inhibition with the IC50 values of 0.50, 0.66, 0.058, 0.20, 0.32, 0.036, 0.026 and 0.37 mM, respectively.

Protective effect of the total flavonoids from Apocynum venetum L. on carbon tetrachloride-induced hepatotoxicity in vitro and in vivo

Apocynum venetum L., belonging to the family Apocynaceae, is a popular medicinal plant, which is commonly used in the treatment of hypertension, neurasthenia, and hepatitis in China. In the present study, the total flavonoids (TFs) were prepared from the leaves of A. venetum, and its protective effects on carbon tetrachloride (CCl4)-induced hepatotoxicity in a cultured HepG2 cell line and in mice were investigated. Cell exposed to 0.4% CCl4 (v/v) for 6 h led to a significant decrease in cell viability, increased LDH leakage, and intracellular reactive oxygen species (ROS). CCl4 also induced cell marked apoptosis, which was accompanied by the loss of mitochondrial membrane potential (MMP). Pretreatment with TFs at concentrations of 25, 50, and 100 μg/mL effectively relieved CCl4-induced cellular damage in a dose-dependent manner. In vivo, TFs (100, 200, and 400 mg/kg BW) were administered via gavage daily for 14 days before CCl4 treatment. The high serum ALT and AST levels induced by CCl4 were dose-dependently suppressed by pretreatment of TFs (200 and 400 mg/kg BW). Histological analysis also supported the results obtained from serum assays. Furthermore, TFs could prevent CCl4-caused oxidative damage by decreasing the MDA formation and increasing antioxidant enzymes (CAT, SOD, GSH-Px) activities in liver tissues. In summary, both in vitro and in vivo data suggest that TFs, prepared from A. venetum, showed a remarkable hepatoprotective and antioxidant activity against CCl4-induced liver damage

Protective effect of the total flavonoids from Apocynum venetum L. on carbon tetrachloride-induced hepatotoxicity in vitro and in vivo.

Apocynum venetum L., belonging to the family Apocynaceae, is a popular medicinal plant, which is commonly used in the treatment of hypertension, neurasthenia, and hepatitis in China. In the present study, the total flavonoids (TFs) were prepared from the leaves of A. venetum, and its protective effects on carbon tetrachloride (CCl4)-induced hepatotoxicity in a cultured HepG2 cell line and in mice were investigated. Cell exposed to 0.4% CCl4 (v/v) for 6 h led to a significant decrease in cell viability, increased LDH leakage, and intracellular reactive oxygen species (ROS). CCl4 also induced cell marked apoptosis, which was accompanied by the loss of mitochondrial membrane potential (MMP). Pretreatment with TFs at concentrations of 25, 50, and 100 µg/mL effectively relieved CCl4-induced cellular damage in a dose-dependent manner. In vivo, TFs (100, 200, and 400 mg/kg BW) were administered via gavage daily for 14 days before CCl4 treatment. The high serum ALT and AST levels induced by CCl4 were dose-dependently suppressed by pretreatment of TFs (200 and 400 mg/kg BW). Histological analysis also supported the results obtained from serum assays. Furthermore, TFs could prevent CCl4-caused oxidative damage by decreasing the MDA formation and increasing antioxidant enzymes (CAT, SOD, GSH-Px) activities in liver tissues. In summary, both in vitro and in vivo data suggest that TFs, prepared from A. venetum, showed a remarkable hepatoprotective and antioxidant activity against CCl4-induced liver damage.

Quality Evaluation of Apocyni Veneti Folium from Different Habitats and Commercial Herbs Based on Simultaneous Determination of Multiple Bioactive Constituents Combined with Multivariate Statistical Analysis.

Apocyni Veneti Folium (AVF) is a kind of staple traditional Chinese medicine with vast clinical consumption because of its positive effects. However, due to the habitats and adulterants, its quality is uneven. To control the quality of this medicinal herb, in this study, the quality of AVF was evaluated based on simultaneous determination of multiple bioactive constituents combined with multivariate statistical analysis. A reliable method based on ultra-fast liquid chromatography tandem triple quadrupole mass spectrometry (UFLC-QTRAP-MS/MS) was developed for the simultaneous determination of a total of 43 constituents, including 15 flavonoids, 6 organic acids, 13 amino acids, and 9 nucleosides in 41 Luobumaye samples from different habitats and commercial herbs. Furthermore, according to the contents of these 43 constituents, principal component analysis (PCA) was employed to classify and distinguish between AVF and its adulterants, leaves of Poacynum hendersonii (PHF), and gray relational analysis (GRA) was performed to evaluate the quality of the samples. The proposed method was successfully applied to the comprehensive quality evaluation of AVF, and all results demonstrated that the quality of AVF was higher than the PHF. This study will provide comprehensive information necessary for the quality control of AVF.

Chemopreventive Potential of Ethanolic Extracts of Luobuma Leaves (Apocynum venetum L.) in Androgen Insensitive Prostate Cancer.

Luobuma (Apocynum venetum L. (AVL)) is a popular beverage in Asia and has been reportedly to be associated with the bioactivities such as cardiotonic, diuretic, antioxidative, and antihypertensive. However, its biofunction as chemoprevention activity is seldom addressed. Herein, we aimed to characterize the anti-androgen-insensitive-prostate-cancer (anti-AIPC) bioactive compounds of Luobuma, and to investigate the associated molecular mechanisms. Activity-guided-fractionation (antioxidative activity and cell survivability) of Luobuma ethanolic extracts was performed to isolate and characterize the major bioactive compounds using Ultra Performance Liquid Chromatography (UPLC), Liquid Chromatography-Mass Spectrometry (LC-MS), and Nuclear Magnetic Resonance (NMR). Plant sterols (lupeol, stigamasterol and ß-sitosterol) and polyphenolics (isorhamnetin, kaempferol, and quercetin) were identified. Lupeol, a triterpene found in the fraction (F8) eluted by 10% ethyl acetate/90% hexane and accounted for 19.3% (w/w) of F8, inhibited the proliferation of PC3 cells. Both lupeol and F8 induced G2/M arrest, inhibition of ß-catenin signaling, regulation of apoptotic signal molecules (cytochrome c, Bcl-2, P53, and caspase 3 and 8), and suppression DNA repair enzyme expression (Uracil-DNA glycosylase (UNG)). To our knowledge, our study is the first report that lupeol inhibited the expression of UNG to elicit the cytotoxicity against androgen-insensitive-prostate-cancer cells. Collectively, Luobuma, which contains several antitumor bioactive compounds, holds the potential to be a dietary chemopreventive agent for prostate cancer.

Purification of quercetin-3-O-sophoroside and isoquercitrin from Poacynum hendersonii leaves using macroporous resins followed by Sephadex LH-20 column chromatography.

In China, Poacynum hendersonii is frequently used as a substitute for Apoacynum venetum L (Luobuma), which is a famous traditional Chinese medicine. Quercetin-3-O-sophoroside and isoquercitrin are two major flavonoids in Poacynum hendersonii leaves. In this work, a suitable method was established for the large-scale preparation of quercetin-3-O-sophoroside (QOS) and isoquercitrin (ISO) from Poacynum hendersonii leaves using macroporous resin combined with Sephadex LH-20 column chromatography. The adsorption/desorption capacities and desorption ratios of six macroporous resins were evaluated using static experiments. The HPD-300 resin had the best adsorption performance because it had the largest surface area, and was selected for further study. Compared with pseudo-first-order and intraparticle diffusion kinetics models, the pseudo-second-order model could better fit the adsorption kinetics of both QOS and ISO on the HPD-300 resin. In addition, the adsorption isotherms of the two compounds on the HPD-300 resin were fitted well to the Langmuir model. Under optimal conditions, the purities of QOS and ISO in the product were increased from 2.16% and 1.26% to 21.34% and 10.70% with recovery yields of 82.1% and 77.3%, respectively. Subsequently, Sephadex LH-20 column chromatography was employed for improving the purities of the two compounds. After separation by Sephadex LH-20 column chromatography, the purities of QOS and ISO achieved 93.5% and 95.6%, respectively.

Apocynum leaf extract inhibits the progress of atherosclerosis in rats via the AMPK/mTOR pathway.

Apocynum leaf extract is an extract of the dried leaves of Apocynum venetum (a member of the Apocynaceae family) that has many effects on the cardiovascular system. The aim of the present study was to evaluate the protective effects of apocynum leaf extract on the atherosclerosis in rats induced by high-fat diet combined with vitamin D3 intraperitoneal injection. The atherosclerosis in rats were induced with a high-fat diet and an intraperitoneal injection of VD3 once daily for three contiguous days at a total injection dose of 70 U/kg. At the end of the 18th week, serum total cholesterol (TC) and triglyceride (TG) contents were measured. Hydroxyproline content in the aorta were measured by the alkali hydrolysis method. The hematoxylin-eosin (HE) and immunohistochemical staining were applied to evaluate the morphological changes and the collagen I and α-smooth muscle actin expression. The protein expression and the mRNA level of AMPK and mTOR were detected by western blot analysis and reverse transcript PCR. After treatment with apocynum leaf extract, the serum total cholesterol and triglyceride concentration of the atherosclerotic rats were significantly decreased, both the Collagen I expression and the hydroxyproline content in the aorta were significantly reduced, and the α-SMA, a smooth muscle-specific marker, expression were also lower than the untreated atherosclerotic rats. Western blot analyses showed that the apocynum can marked increase the p-AMPK but decrease the mTOR protein expression. The apocynum leaf extract also exhibited higher AMPK and lower mTOR mRNA expression of the aorta in the atherosclerotic rats. We believe that the apocynum leaf extract can effectively reduce blood lipid levels in rats with atherosclerosis, delay atherosclerotic progression by inhibiting excessive collagen synthesis and inhibiting smooth muscle cell over-proliferation. The underlying mechanism may be related to the AMPK/mTOR signaling pathway activity. Our results contribute towards validation of the traditional use of apocynum leaf extract in the treatment of atherosclerosis.

Extraction, Preconcentration and Isolation of Flavonoids from Apocynum venetum L. Leaves Using Ionic Liquid-Based Ultrasonic-Assisted Extraction Coupled with an Aqueous Biphasic System.

BACKGROUND: Ionic liquids (ILs) are considered as green solvents, and widely applied for the extraction of various compounds. METHODS: The present research focuses on the extraction of flavonoids from Apocynum venetum L. leaves by ultrasound-assisted extraction (UAE). Several major influencing factors were optimized. Then, an aqueous biphasic system (ABS) was applied for further isolation of flavonoids. RESULTS: The flavonoids were mainly distributed in the top phase, while impurities were extracted to the bottom phase. The parameters influencing the extraction, namely type and concentration of salt, temperature, and pH, were studied in detail. Under optimized conditions (72.43% IL extract, 28.57% (NH4)2SO4, 25 °C temperature, pH 4.5), the preconcentration factor and extraction efficiency were found to be 3.78% and 93.35%, respectively. CONCLUSIONS: This simple and efficient methodology is expected to see great use in the extraction and isolation of pharmaceutically active components from medicinal plant resources.

iTRAQ-based quantitative proteomic analysis of the anti-apoptotic effect of hyperin, which is mediated by Mcl-1 and Bid, in H2O2-injured EA.hy926 cells.

Endothelial injury has been implicated in the pathogenesis of many cardiovascular diseases, including thrombotic disorders. Hyperin (quercetin-3-O-galactoside), a flavonoid compound and major bioactive component of the medicinal herb Apocynum venetum L., is commonly used to prevent endothelium dysfunction. However, its mode of action remains unclear. To the best of our knowledge, we have for the first time investigated the protective effect hyperin exerts against H2O2-induced injury in human endothelium-derived EA.hy926 cells using isobaric tags for relative and absolute quantitation (iTRAQ)­based quantitative proteomic analysis. The results showed that H2O2 exposure induced alterations in the expression of 250 proteins in the cells. We noted that the expression of 52 proteins associated with processes such as cell apoptosis, cell cycle and cytoskeleton organization, was restored by hyperin treatment. Of the proteins differentially regulated following H2O2 stress, the anti-apoptotic protein, myeloid cell leukemia-1 (Mcl-1), and the pro-apoptotic protein, BH3-interacting domain death agonist (Bid), exhibited marked changes in expression. Hyperin increased Mcl-1 expression and decreased that of Bid in a dose-dependent manner. In addition, flow cytometric analysis and western blot analysis of the apoptosis-related proteins, truncated BID (tBid), cleaved caspase-3, cleaved caspase-9, Fas, FasL and caspase-8, demonstrated that the rate of apoptosis and the pro-apoptotic protein levels were decreased by hyperin pre­treatment. In the present study we demonstrate that hyperin effectively prevents H2O2­induced cell injury by regulating the Mcl­1­ and Bid-mediated anti­apoptotic mechanism, suggesting that hyperin is a potential candidate for use in the treatment of thrombotic diseases.

Endothelium-Dependent Relaxation Effect of Apocynum venetum Leaf Extract via Src/PI3K/Akt Signalling Pathway.

Botanical herbs are consumed globally not only as an essential diet but also as medicines or as functional/recreational food supplements. The extract of the Apocynum venetum leaves (AVLE), also known as Luobuma, exerts its antihypertensive effect via dilating the blood vessels in an endothelium- and concentration-dependent manner with optimal effect seen at as low as 10 µg/mL. A commercial Luoboma "antihypertensive tea" is available commercially in the western province of China. The present study seeks to investigate the underlying cellular mechanisms of the nitric oxide (NO)-releasing property of AVLE in rat aortas and human umbilical vein endothelial cells (HUVECs). Endothelium-dependent relaxation induced by AVLE was assessed in organ chambers in the presence or absence of polyethyleneglycol catalase (PP2, 20 µM; inhibitor of Src kinase), wortmannin (30 nM) and LY294002 (20 µM; PI3 (phosphatidylinositol3)-Kinase inhibitor), N(G)-nitro-L-arginine (L-NAME, 100 µM; endothelial NO synthase inhibitor (eNOS)) and ODQ (1 µM; soluble guanylyl cyclase inhibitor). Total nitrite and nitrate (NOx) level and protein expression of p-Akt and p-eNOS were measured. AVLE-induced endothelium-dependent relaxation was reduced by PP2, wortmannin and LY294002 and abolished by L-NAME and ODQ. AVLE significantly increased total NOx level in rat aortas and in HUVECs compared to control. It also instigated phosphorylation of Akt and eNOS in cultured HUVECs in a concentration-dependent manner and this was markedly suppressed by PP2, wortmannin and LY294002. AVLE also inhibited superoxide generated from both NADPH oxidase and xanthine/xanthine oxidase system. Taken together, AVLE causes endothelium-dependent NO mediated relaxations of rat aortas through Src/PI3K/Akt dependent NO signalling pathway and possesses superoxide scavenging activity.

Microemulsion liquid chromatographic method for simultaneous separation and determination of six flavonoids of Apocynum venetum leaf extract.

A simple, cost-effective, and efficient method was developed for the rapid simultaneous separation and determination of six flavonoids (rutin, hyperoside, quercetin-3-O-sophoroside, isoquercitrin, astragalin and quercetin) of Apocynum venetum leaf extract by reversed phase high performance liquid chromatography using a microemulsion system mixture as the mobile phase. Separations were performed on the Zorbax Extend-C18 column with UV detection at 360nm. The flow rate was 0.8mLmin(-1). The optimized microemulsion mobile phase consisted of 2.5% (v/v) n-butanol, 1.2% (v/v) of Genapol X-080, 0.5% (v/v) ethyl acetate and 95.8% (w/v) of aqueous 20mM phosphoric acid, pH adjusted to 6.0 with 0.3% triethylamine. Under the optimized conditions, the calibration curve for six flavonoids was linear in the range of 5-1000µgmL(-1) with the correlation coefficients greater than 0.9994. The intra-day and inter-day precision (RSD) were below 8.11% and the limits of detection (LOD) for the six flavonoids were 1.7-6.0µgmL(-1) (S/N=3). The microemulsion liquid chromatography (MELC) method was successfully applied to separate and determine the six flavonoids of A. venetum leaf extract.

Application of mixed cloud point extraction for the analysis of six flavonoids in Apocynum venetum leaf samples by high performance liquid chromatography.

A simple, inexpensive and efficient method based on the mixed cloud point extraction (MCPE) combined with high performance liquid chromatography was developed for the simultaneous separation and determination of six flavonoids (rutin, hyperoside, quercetin-3-O-sophoroside, isoquercitrin, astragalin and quercetin) in Apocynum venetum leaf samples. The non-ionic surfactant Genapol X-080 and cetyl-trimethyl ammonium bromide (CTAB) was chosen as the mixed extracting solvent. Parameters that affect the MCPE processes, such as the content of Genapol X-080 and CTAB, pH, salt content, extraction temperature and time were investigated and optimized. Under the optimized conditions, the calibration curve for six flavonoids were all linear with the correlation coefficients greater than 0.9994. The intra-day and inter-day precision (RSD) were below 8.1% and the limits of detection (LOD) for the six flavonoids were 1.2-5.0 ng mL(-1) (S/N=3). The proposed method was successfully used to separate and determine the six flavonoids in A. venetum leaf samples.

[Evaluation of high-resolution images application for wild medicinal plants macro monitoring: a case of Apocynum].

To investigate the resources of medicinal plant, such as wild Apocynum, supervised classification based on Principal Component Analysis (PCA) and texture feature were used to monitor wild medicinal plants from image captured by ZY-3 and World-view-2 and compare which satellite Image are more appropriate to monitor the wild medicinal plants. The research results shows that: for more complex growth conditions wild medicinal plants Apocynum, high-resolution images Worldview-2 is more suitable for its remote identification, the low-resolution satellite ZY-3 can only recognizes the wild medicinal plants which distributed intensively. If the study target distribution is more intensive and larger scale, and cultivated type medicinal plants, the use of satellite ZY-3 in low resolution remote sensing data to identify the target can be a good choice, it is not necessary to buy high-resolution data, in order to avoid waste of expenditure, for the scattered distribution, the high-resolution satellite imagery data may be indispensable to identify targets.

Porous membrane ultrafiltration-A novel method for enrichment of the active compounds from micro-plasma samples.

To enrich the active compounds from plasma samples, a novel and simple method has been developed using a porous membrane envelope based on the ultrafiltration technique combining with high-performance liquid chromatography. The ultrafiltration device is a sealed porous membrane envelope prepared with a polypropylene sheet to effectively separate the active small molecules and large biomolecules, and a sample carrier is held inside the envelope to load plasma samples. The enrichment of hyperoside and isoquercitrin from rat plasma was used as an example. Significant factors of this method, such as membrane types, the desorption solvent, and the desorption time were optimized for the ultrafiltration method. Under the optimal conditions, correlation coefficients of 0.999 and 0.998 were obtained for hyperoside and isoquercitrin, respectively, with a linear range between 0.5 and 100µg/mL. The absolute extraction recoveries from 83.2% to 86.8% were achieved. The detection limits of the method for hyperoside and isoquercitrin were 0.22 and 0.20µg/mL, respectively. Compared with protein precipitation, solid-phase extraction and commercial ultrafiltration membrane methods, our proposed method demonstrates lower detection limits and lower cost for extraction. Also, it consumes less plasma samples and is found to be applicable to biological samples.