Mechanism of Cucurbitacin B in Regulating Glycolysis and Inhibiting Proliferation of HuCCT1 Cells / 中国实验方剂学杂志

ObjectiveTo explore the mechanism of cucurbitacin B （CuB） in inhibiting cell proliferation and glycolysis. MethodCell counting kit-8 （CCK-8） was applied to investigate the effect of different concentrations of CuB （0， 40， 80， 120， 160， 200， 400， and 800 nmol·L-1） on the proliferation of HuCCT1 cells. The effect of different concentrations of CuB （50， 100， and 200 nmol·L-1） on the colony formation ability of HuCCT1 cells was detected by plate cloning assay. The effect of different concentrations of CuB （50， 100， 200 nmol·L-1） on the HuCCT1 cell cycle was analyzed by flow cytometry. Visible spectrophotometry was employed to detect the activity of key glycolytic enzymes hexokinase （HK） and pyruvate kinase （PK）） and changes in glucose consumption， lactate production， and adenosine triphosphate （ATP） production in HuCCT1 cells after administration of different concentrations of CuB （50， 100， 200 nmol·L-1）. Western blotting was used to assay the effect of CuB on the expression of cell cycle-related proteins， proliferation-related proteins， key glycolytic proteins， and Akt/mammalian target of rapamycin （mTOR） pathway-related proteins. ResultAs compared with the blank group， CuB at dose of 160-800 nmol·L-1 after 24 h administration and CuB at dose of 80-800 nmol·L-1 after 48 h administration inhibited the proliferation of HuCCT1 cells in a time- and dose-dependent manner （P<0.05， P<0.01）， and the median inhibitory concentration was 200 nmol·L-1 48 h after administration. CuB can restrain the colony formation ability of HuCCT1 cells in a dose-dependent manner （P<0.01）， and block HuCCT1 cell cycle in G2 phase （P<0.05， P<0.01）. CuB （100 and 200 nmol·L-1） can suppress the activities of HK and PK and reduce cell glucose consumption and production of lactate and ATP （P<0.05， P<0.01）. Western blot results showed that CuB （100 and 200 nmol·L-1） can inhibit the protein levels of cycle-related protein Cyclin B1， proliferating cell nuclear antigen （PCNA）， HK1， HK2， PKM1， PKM2， phosphorylated Akt （p-Akt）， phosphorylated mTOR （p-mTOR）， and phosphorylated ribosomal protein S6 （p-RPS6） （P<0.05， P<0.01）. ConclusionCuB can inhibit aerobic glycolysis in HuCCT1 cells via the Akt/mTOR pathway， thereby affecting cell proliferation.

Inhibitory effects of cucurbitacin B combined with oxaliplatin on proliferation and apoptosis of human colon cancer SW480 cells and their mechanisms / 吉林大学学报(医学版)

Objective: To expore the effects of cucurbitacin B (CUB) combined with oxaliplatin (OXA) on the proliferation and apoptosis of human colon cancer SW480 cells, and to clarify their mechanisms. Methods: The SW480 cells were divided into control group, 10, 20, and 40 μmol • L-1 CUB groups, OXA group (100 μmol • L _ 1 ) and combination group (40 μmol • L _ 1 CUB + 1 0 0 μmol • L _ 1 O X A). The proliferation rate of the SW480 was determined by M T T assay. Hoechst33258 staining was used to observe the morphology of SW480 cells. The cell cycle and apoptotic rates of SW480 cells were detected by flow cytometry. The expressions levels of caspase-3, cleaved caspase-3, Bax and Bcl-2 proteins were measured by Western blotting method. Results: The M T T results showed that compared with control group, the proliferation rates of the SW480 cells in different doses of CUB groups and OXA group were significantly decreased (P < 0. 0 5); compared with different doses of CUB groups and OXA group, the proliferation rate of the SW480 cells in combination group was significantly decreased (P < 0. 05). The results of Hoechst 33258 staining showed that the blue fluorescence in the SW480 cells in different doses of CUB groups and OXA group were brighter than that in control group, which showed granular blue fluorescence in the cell nucles. Compared with different doses of CUB groups and OXA group, the blue fluorescence in the SW480 cells in combination group was more significantly bright, and granular blue fluorescence was significantly increased. The cell cycle detection results of flow cytometry showed that compared with control group, the percentages of the SW480 cells in G2/M phase in different doses of CUB groups and combination group were incresaed (P < 0. 0 5); the percentages of SW480 cells in S phase in 40 μmol • L _ 1 CUB group, OXA group and combination group were incresaed (P < 0. 05). The apoptosis detection results of flow cytometry showed that compared with control group, the apoptotic rates of the SW480 cells in different doses of CUB groups and OXA group were increased (P < 0. 05); compared with different doses of CUB groups and OXA group, the apoptotic rate of the SW480 cells in combination group was significantly increased (P < 0. 05). The Western blotting results showed that compared with control group, the expressions levels of caspase-3 and Bcl-2 in the SW480 cells in different doses of CUB groups and OXA group were decreased (P < 0. 0 5), the expression levels of cleaved caspase-3 and Bax were increased (P < 0. 05), and the Bcl-2/Bax ratios were decreased (P < 0. 05); compared with different doses of CUB groups and OXA group, the changes of the above protein expression levels, the cleaved caspase-3/caspase-3 ratio and the Bcl-2/Bax ratio in combination group were more obvious (P < 0. 05). Conclusion: CUB combined with OXA can effectively inhinbit the proliferation of colon cancer SW480 cells, and its mechanism may be related to the S and G2/M phase arrest, up regulation of the ratio of cleaved-caspase-3/caspase-3 and down-regulation of the ratio of Bcl-2/Bax.

Analysis of quality markers based on efficacy and material base of different medicinal parts of Trichosanthes kirilowii / 中草药

Different parts of Trichosanthes kirilowii can all be used as medicines, including the fruits (Trichosanthis Fructus), pericarps (Trichosanthis Pericarpium), seeds (Trichosanthis Semen) and roots (Trichosanthis Radix). Modern research has confirmed that the main active ingredients of Trichosanthis Pericarpium are flavonoids and amino acids; Trichosanthis Semen mainly contains terpenoids and sterols; Trichosanthis Radix mainly contains protein, steroids and polysaccharides. And the pharmacological effects of various medicinal parts are also different. This paper summarizes the traditional efficacy, chemical composition and modern pharmacological effects of different medicinal parts of T. kirilowii, analyzes the relationship between them, so as to analyze and predict the quality marker of T. kirilowii.

Effect of 60Co-γ ray irradiation on five active ingredients in Infantile Qingfei Pills / 中草药

Objective To establish HPLC method for simultaneous determination of five active ingredients of cucurbitacin B, cucurbitacin E, praeruptorin A, praeruptorin B, and praeruptorin E in Infantile Qingfei Pills (IQP), and study the contents changes of the five effective components in IQP before and after 60Co-γ ray irradiation. Methods The Agilent-C18 column (250 mm × 4.6 mm, 5 μm) was adopted and the detection wavelength was 230 nm and 321 nm with the flow rate of 1.0 mL/min. The mobile phase consisted of A (methanol: acetonitrile) and B (0.5% glacial acetic acid solution) for gradient elution, and column temperature was 25 ℃. Irradiation does of 2, 4, 6, 8 kGy were selected to irradiate IQP respectively. The contents of five active components in IQP were compared before and after irradiation, and the significant condition was observed by t-test. Results The linear range of cucurbitacin B, cucurbitacin E, praeruptorin A, praeruptorin B, and praeruptorin E were 0.049—1.247, 0.079—1.973, 0.056—1.406, 0.028—0.705, and 0.028—0.693 μg, The average recovery were 101.2%, 99.7%, 99.9%, 98.9%, and 100.5%, and RSD were 0.6%, 0.5%, 1.2%, 1.1%, and 1.2%, respectively. After irradiation of 2, 4, 6, and 8 kGy, the effective components contents of cucurbitacin B, cucurbitacin E, praeruptorin A, praeruptorin B, and praeruptorin E were changed. After t-test in groups, the content change of cucurbitacin B was significantly after irradiation over 6 kGy (P < 0.05). Conclusion The established method has a high recovery rate, good repeatability, which is simple and practical and can be used for quality control of IQP. The changes of each component are not significant with the radiation no more than 6 kGy, which can provide a reference for the sterilization of IQP.

Cucurbitacin B suppresses metastasis mediated by reactive oxygen species (ROS) via focal adhesion kinase (FAK) in breast cancer MDA-MB-231 cells / 中国天然药物

Metastasis is responsible for the majority of cancer-related deaths and prevention of metastasis remains a big challenge for cancer therapy. Cucurbitacin B (Cuc B) is a natural triterpenoid with potent anticancer activities while its effect on metastasis remains unclear. In the present study, the inhibitory effect and mechanisms of Cuc B on metastasis were investigated in MDA-MB-231 breast cancer cells. The cells were treated with or without Cuc B, and the cytotoxicity was determined by MTT assay. The effect of Cuc B on metastasis was evaluated with wound healing, transwell, and adhesion assays. Furthermore, the adhesion of cancer cells to endothelial cells was determined. The protein expression was determined by Western blotting. Cuc B (< 100 nmol·L) showed no obvious cytotoxicity to MDA-MB-231 cells, but significantly inhibited migration, invasion, and adhesion to Matrigel, fibronectin, type I collagen, and endothelial cells. Cuc B dramatically inhibited the phosphorylation of focal adhesion kinase (FAK) and paxillin in dose- and time-dependent manners. Furthermore, Cuc B induced intracellular reactive oxygen species (ROS) generation, which could be reduced by N-acetyl-l-cysteine (NAC). In addition, NAC pretreatment could reverse Cuc B-induced suppression of migration and adhesion, expression of FAK, but showed no effect on paxillin expression. In summary, Cuc B suppressed ROS-dependent metastasis through FAK pathway in breast cancer MDA-MB-231 cells, demonstrating novel mechanisms for the anticancer effects of Cuc B.

Cucurbitacin B suppresses metastasis mediated by reactive oxygen species (ROS) via focal adhesion kinase (FAK) in breast cancer MDA-MB-231 cells / 中国天然药物

Metastasis is responsible for the majority of cancer-related deaths and prevention of metastasis remains a big challenge for cancer therapy. Cucurbitacin B (Cuc B) is a natural triterpenoid with potent anticancer activities while its effect on metastasis remains unclear. In the present study, the inhibitory effect and mechanisms of Cuc B on metastasis were investigated in MDA-MB-231 breast cancer cells. The cells were treated with or without Cuc B, and the cytotoxicity was determined by MTT assay. The effect of Cuc B on metastasis was evaluated with wound healing, transwell, and adhesion assays. Furthermore, the adhesion of cancer cells to endothelial cells was determined. The protein expression was determined by Western blotting. Cuc B (< 100 nmol·L) showed no obvious cytotoxicity to MDA-MB-231 cells, but significantly inhibited migration, invasion, and adhesion to Matrigel, fibronectin, type I collagen, and endothelial cells. Cuc B dramatically inhibited the phosphorylation of focal adhesion kinase (FAK) and paxillin in dose- and time-dependent manners. Furthermore, Cuc B induced intracellular reactive oxygen species (ROS) generation, which could be reduced by N-acetyl-l-cysteine (NAC). In addition, NAC pretreatment could reverse Cuc B-induced suppression of migration and adhesion, expression of FAK, but showed no effect on paxillin expression. In summary, Cuc B suppressed ROS-dependent metastasis through FAK pathway in breast cancer MDA-MB-231 cells, demonstrating novel mechanisms for the anticancer effects of Cuc B.

Content Determination and Grey Relational Analysis of Cucurbitaceaes in Five Varieties of Cucurbitaceae Plants / 中国药师

Objective: To establish an HPLC method for the content determination of cucurbitacin B and E in cucurbitaceae plants, and evaluate the quality of cucurbits by grey relational analysis.Methods: A Diamonsil-C18 column (250 mm×4.6 mm, 5 μm) was adopted and the UV detection wavelength was 234 nm at the flow rate of 1.0 ml·min-1.The mobile phase consisted of 0.1% acetic acid and acetonitrile with gradient elution, and the column temperature was 30℃.In addition,grey relational analysis was carried out for the comprehensive evaluation.Results: The linear range of cucurbitacin B and E was 0.894-44.715 μg·ml-1(r=0.999 6) and 0.257-12.825 μg·ml-1(r=0.999 7),respectively.The average recovery was 98.8%-100.3% and 98.0%-100.1%(RSD＜0.88%,n=6), respectively.According to the grey correlation analysis on the components, Cucumis melo L had the best quality, and Momordica cochinchinensis (Lour.) Spreng showed the worst quality.Conclusion: The established method is rapid and convenient, which can be used for the content determination of cucurbitacin B and E in cucurbits, and the comprehensive quality evaluation of cucurbits.

A study on the effect of Cucurbitacin B on the inflammatory reaction of murine alveolar macrophages induced by lipopolysaccharide / 预防医学

Objective To investigate the anti-inflammatory effect of Cucurbitacin B on the inflammatory reaction of murine alveolar macrophages induced by lipopolysaccharide and its molecular mechanism. Methods The alveolar macrophages were randomly divided into five groups: blank group, LPS group, different concentrations of Cucurbitacin B (1μM, 2.5μM, 5μM)+) +LPS groups. All group cells were pretreated with different concentrations for 2 h, and followed by 1μg/mL LPS. The protein level of TNF-α, IL-1β, IL-6 and PGE2 were detected by ELISA assay, and the NO was detected by Griess methods, and its upstream protein i-NOS,COX-2, Nrf2 and HO-1 were detected by Western-blot. Results The secretion of TNF-α, IL-1β, IL-6 and PGE2 in LPS group were increased significantly than blank groups, while Cucurbitacin B suppressed its protein level inadose-dependent manner. The nuclear erythroid related factor 2 and antioxidant gene were activated while Cucurbitacin B was added into alveolar macrophages in adose-dependent manner. Conclusion Cucurbitacin B can inhibit the extracellar secretion of inflammatory cytokines production, and its molecular mechanism could be due to the promoting Nrf2 translocation to the nucleus, activating the expression of HO-1 gene, reducing the expression of iNOS and COX-2, and thereby alleviating the inflammatory reaction.

Anticancer and anti-inflammatory activities of some dietary cucurbits.

In this study, we investigated few dietary cucurbits for anticancer activity by monitoring cytotoxic (MTT and LDH assays), apoptotic (caspase-3 and annexin-V assays), and also their anti-inflammatory effects by IL-8 cytokine assay. Aqua-alcoholic (50:50) whole extracts of cucurbits [Lagenaria siceraria (Ls), Luffa cylindrica (Lc) and Cucurbita pepo (Cp)] were evaluated in colon cancer cells (HT-29 and HCT-15) and were compared with isolated biomolecule, cucurbitacin-B (Cbit-B). MTT and LDH assays revealed that the cucurbit extracts and Cbit-B, in a concentration dependent manner, decreased the viability of HT-29 and HCT-15 cells substantially. The viability of lymphocytes was, however, only marginally decreased, yielding a potential advantage over the tumor cells. Caspase-3 assay revealed maximum apoptosis with Ls while annexin V assay demonstrated maximum efficacy of Lc in this context. These cucurbits have also shown decreased secretion of IL-8, thereby revealing their anti-inflammatory capability. The results have demonstrated the therapeutic potential of dietary cucurbits in inhibiting cancer and inflammatory cytokine.

Preparation and characterization of cucurbitacin B phospholipids complex and its in vitro antitumor activity / 中草药

Objective: To prepare cucurbitacin B phospholipids complex (CuB-PLC) and evaluate its physicochemical properties and in vitro antitumor activity. Methods: CuB-PLC was prepared using solvent evaporation method and optimized by Box-Behnken design. The oil-water partition coefficient, particle size, and morphology of CuB-PLC were investigated; X-ray diffraction (XRD) spectroscopy and infrared (IR) spectroscopy were used to analyze the formation machenism of CuB-PLC. MTT method was used to determine the in vitro antitumor activity of CuB-PLC. Results: The optimal formulation protocol for CuB-PLC was as follows: Tetrahydrofuran was taken as the reaction medium, phospholipids-cucurbitacin B molar ratio, reaction concentration of cucurbitacin B, reaction temperature and time were 1:1, 1.5 mg/mL, 60℃, and 3 h, respectively. The complex rate and particle size for the optimized CuB-PLC was 97.15% and (521.30 ± 10.50) nm, and the polydispersity index (PDI) was 0.133 2 ± 0.024 0. MTT experiments showed that the half of the HepG-2 cell proliferation inhibition concentration (IC50) values of CuB and CuB-PLC were 42.55 and 27.61 μmol/L. Conclusion: CuB-PLC is successfully developed under the optimized protocol, possessing high complex rate, and enhanced solubility in water, and the inhibition on HepG-2 cell proliferation is significantly enhanced, which provides the reference for the further research of CuB.

Modulation of signal transduction pathways by natural compounds in cancer / 中国天然药物

Cancer is generally regarded as the result of abnormal growth of cells. According to World Health Organization, cancer is the leading cause of mortality worldwide. Mother nature provides a large source of bioactive compounds with excellent therapeutic efficacy. Numerous phytochemicals from nature have been investigated for anticancer properties. In this review article, we discuss several natural compounds, which have shown anti-cancer activity. Natural compounds induce cell cycle arrest, activate intrinsic and extrinsic apoptosis pathways, generate Reactive Oxygen Species (ROS), and down-regulate activated signaling pathways, resulting in inhibition of cell proliferation, progression and metastasis of cancer. Several preclinical studies have suggested that natural compounds can also increase the sensitivity of resistant cancers to available chemotherapy agents. Furthermore, combining FDA approved anti-cancer drugs with natural compounds results in improved efficacy. On the basis of these exciting outcomes of natural compounds against several cancer types, several agents have already advanced to clinical trials. In conclusion, preclinical results and clinical outcomes against cancer suggest promising anticancer efficacy of agents from natural sources.

Determination of content of cucurbitacin B in cucurbitacins by HPLC / 药学实践杂志

Objective To determina the content of cucurbitacin B in cucurbitacins .Methods The highly effective liquid phase chromatography was used,with Waters Symmetry C18(250 mm ×4.6 mm 5μm) column.The mobile phase was acetonitrile-wa-ter (51:49), the flow rate was 1 ml/min, column temperature was 25 ℃, the detection wavelength was 228 nm.Results Cucurb-itacin B regression equation:Y=1 067.3C-0.508 4 (r=0.999 9), the average recovery rate was 99.39%(n=6), RSD was 0.56%, which showed that this method had a good recovery rate .Conclusion The HPLC method for the determination of content of cucurbitacin B in cucurbitacins was simple , reproducible , accurate .

Cytotoxicity evaluation of cucurbitacin B solid lipid nanoparticles (SLN) on human neuroblastoma SK-N-SH cell line in vitro / 中国药学杂志

OBJECTIVE: To evaluate the cytotoxicity of cucurbitacin B solid lipid nanoparticles (SLN) on human neuroblastoma SK-N-SH cell line in vitro. METHODS: The SK-N-SH cell line was treated with cucurbitacin B SLN at various concentrations. Growth suppression was evaluated by MTT method; apoptosis related alterations in morphology were ascertained under light microscopy. Flow cytometry (FCM) was used to investigate the distribution of cell life. RESULTS: Free cucurbitacin B and cucurbitacin B SLN inhibited the growth of SK-N-SH cells after 48 h treatment in a dose dependent manner, with IC50 values of 0.508 and 12.6 μmol · L-1, respectively. The apoptotic rates at concentrations of 0.143 and 0.716 μmol · L-1 were (34.9 ± 4.6)% and(53.6 ± 6.3)%, respectively, all of which were significantly higher than that of free cucurbitacin B (13.2 ± 2.3)% and(43.4 ± 5.5)% (P < 0.05), respectively. Under microscopy, the cells treated with free cucurbitacin B and cucurbitacin B SLN exhibited characteristics of apoptosis including decreased cell density of groups, reduced cell volume, and changed form of majority cell. Flow cytometry analysis suggested that free cucurbitacin B retarded the progression of cell cycle at G2/M and S phase, and cucurbitacin B SLN retarded the progression of cell cycle at G2/M phase. CONCLUSION: Cucurbitacin B can not only inhibit the proliferation but also induce apoptosis of human neuroblastoma SK-N-SH cell line, demonsting strong cytotoxicity. Cytotoxicity of cucurbitacin B SLN is higher than that of free cucurbitacin B.

High performance liquid chromatography determination of cucurbitacins in the roots of Wilbrandia ebracteata Cogn. / Determinação de cucurbitacinas em raízes de Wilbrandia ebracteata Cogn. por cromatografia líquida de alta eficiência

Roots of Wilbrandia ebracteata Cogn., Cucurbitaceae, used in folk medicine for treatment of rheumatic disease, are rich in cucurbitacins. Dihydrocucurbitacin B is the most abundant cucurbitacin while cucurbitacin B is a minor component. A reverse-phase HPLC system was developed for simultaneous quantitative assay of these cucurbitacins in the roots. The optimised experimental conditions were acetonitrile/H(2)0 40:60, flow-rate 1.2 mL/min., detection at 230 nm and isocratic elution. A variety of sample preparation modes were tested and the extraction with dichloromethane under reflux gave better results. The validation process included linearity, accuracy, repeatability and intermediate precision. The calibration curve of dihydrocucurbitacin B was linear from 40.00 to 400 μg/mL, the recovery was 95.5±3.01 percent, the intermediate precision was found to be 1.64 percent and the repeatability varied between 1.30 to 2.05 percent. The calibration curve of cucurbitacin B was linear from 4.00 to 240 μg/mL, intermediate precision was found to be 2.29 percent and repeatability varied between 1.03 to 2.95 percent. Analysis of the same specimen of W. ebracteata every year from 2002 to 2005 revealed a great rise on the cucurbitacin B concentration after the root was attacked by an herbivore.

Raízes de Wilbrandia ebracteata Cogn. (Cucurbitaceae), tradicionalmente empregada no tratamento de doenças reumáticas, contém cucurbitacinas, sendo di-hidrocucurbitacina B a mais abundante, enquanto cucurbitacina B está presente em menor quantidade. Foi desenvolvido um método para determinação quantitativa destas cucurbitacinas. Os parâmetros selecionados foram: eluente isocrático acetonitrila/H(2)0 40:60, fluxo 1,2 mL/min. e detecção em 230 nm. Diversas formas de preparo da amostra foram testadas, sendo que extração com diclorometano sob refluxo forneceu o melhor resultado. O processo de validação incluiu: linearidade, exatidão, repetibilidade e precisão intermediária. A curva de calibração para a di-hidrocucurbitacina B foi linear de 40.00 to 400 μg/mL, a recuperação foi 95,5±3.01 por cento, a precisão intermediária, 1,64 por cento e a repetibilidade variou entre 1,30 a 2,05 por cento. A curva de calibração da cucurbitacina B foi linear de 4,00 to 240 μg/mL, a recuperação encontrada foi igual a 96,6±2.45 por cento, a precisão intermediária, 2,29 por cento e a repetibilidade variou entre 1,03 a 2,95 por cento. Análise do mesmo espécime de W. ebracteata uma vez por ano de 2002 a 2005 revelou grande aumento no teor de cucurbitacina B após a raiz ter sido atacada por herbívoro.

Antiproliferative effect of cucurbitacin B extracted from trichosanthes cucumerina L. on human cancer cell lines.

Objective: To determine the antiproliferative effect of cucurbitacin B extracted from Trichosanthes cucumerina L. on human cancer cell lines. Methods: Two human lung non-small cell (adenocarcinoma) cancer cell lines i.e., LK87, and QG95, two human colon adenocarcinoma cell lines i.e., HCT15, and HT29, including one renal cancer cell line, A498, and one pancreatic cancer cell line, NOR-P, were used in this study. The viability of cells was assessed by using WST-8 which is based on detection of LDH released from damaged cells and reacts with WST-8 to form a yellow color. Cells were treated with the compound at various concentration from 1 through 100 µg/ml. Results: The ED50 values (effective doses that are required for 50% inhibition growth of tumor cells) of the compound on human cancer cell lines ranged from approximately 69 µg/ml in HCT15 cells up to 231 µg/ml in QG95 cells. The inhibition of proliferation of this compound on these human cancer cell lines was observed to be in a dose dependent manner. Conclusion: It could be concluded from this observation that this compound has a modest direct toxic effect to these cell lines with the highest toxic effect on human colon cancer cells.

Preparation and Optimization of Formulation of PLGA Microspheres Containing Chinese Herbal Extract Cucurbitacin B / 中国药房

OBJECTIVE: To prepare Polylactic-co-glycolic acid)(PLGA) microspheres loaded with Chinese herbal extract cucurbitacin B.METHODS: Cucurbitacin B loaded by PLGA microspheres were prepared by modified emulsification-solvent evaporation method.Central composite design-response surface method was applied to optimize the formulation with PVA concentration and ratio of drug to polymer as independent variables,and with yield of microspheres(Y1),drug loading amount(Y2),encapsulation efficiency(Y3),mean particle diameter(Y4),and the cumulative percentage of the drug release in 24 hr(Y5) as indexes to conduct multiple linear regression and second-order polynomial equation fitting.In vitro release test was performed by modified immediate release method.RESULTS: The results showed that all response variables were greatly fitted by a second-order polynomial equation.The optimal formulation was proved to be as follows: PVA concentration was 0.014 and ratio of drug to polymer was 0.066 5.The microspheres prepared in the optimal formulation were spherical and had smooth surface.Y1,Y2,Y3,Y4,and Y5 were 79.9%,7.83%,80.5%,56.18 ?m and 6.98%,respectively.The cumulative release from microspheres within 35 days reached 86.73%.CONCLUSION: Cucurbitacin B-PLGA microspheres are characterized by prolonged action and sustained-release.Furthermore,the established model has satisfactory predictability.

Determination of cucurbitacin B in Pedicellus Melo by capillary zone electrophoresis / 中成药

AIM:To develop a new method to determine cucurbitacin B in Pedicellus Melo by capillary zone(electrophoresis(CZE).) METHODS:All the samples were analysed on a fused silica capillary(75 cm?75 ?m I.D.) by using 50 mmol/L sodium borate solution(containing 5% acetonitrile) as the background electrolyte with the running voltage at 12.0 kV and detection wavelength of 265 nm.And clorprenaline hydrochloride was applied as the internal standard. RESULTS:The results showed a good linear correlation between relative peak area of cucurbitacin B(y) and its concentration(x) over the range of 0.15～1.2 mg/mL.Regression equation was y=(0.003 4x)+0.058,r=0.999 7,and the average recovery for baicalin was 100.2% with the RSD at(2.11%). CONCLUSION:The method is rapid,simple,reproducible and produces low pollution.It serves as a novel way to determine cucurbitacin B.