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Howeida M.A.,Ahfad University for Women | Idris E.B.,University of Khartoum | Almahdi A.M.,University of Khartoum | Sania S.A.,University of Khartoum | And 2 more authors.
Research Journal of Pharmacology | Year: 2010

The aqueous and methanolic extracts of the bark of C. verum were studied for their hypoglycaemic and hypolipidaemic effects in hyperglycaemic (type II) and in streptozotocin diabetic rats (type I). The hypoglycaemic effect was determined following the Glucose Tolerance Test (GTT) model and the results were compared to the control. The results of this research in type II showed an early and persistent hypoglycaemic effect, since the first hour and throughout the experiment. Both doses of the aqueous extract and dose 200 mg kg -1 of the methanolic extract, revealed the highest significant glucose lowering effect (p<0.001) as compared to the control, followed by dose 400 mg kg-1 of the methanolic extract, which reduced blood glucose significantly (p<0.05) throughout the experiment. The onset of hypoglycaemic effect in diabetic rats was slow but highly significant as started at the 12th h. The reference drugs revealed no significant hypoglycaemic effect throughout the experiment. Regarding blood cholesterol, the onset of the hypocholesterolaemic effect in type II started with a significant reduction (p<0.05) at the 2nd h post dosing and continued till the 4th h post dosing. Glibenclamide reduced blood cholesterol significantly (p<0.05) at the 2nd h only. Both extracts of C. verum showed no significant cholesterol reduction in type I diabetic rats. Insulin reduced blood cholesterol significantly (p<0.05) at the 2nd h only. Concerning the effect of C. verum on the level of blood triglycerides, the aqueous and methanolic extracts, reduced blood triglycerides of hyperglycaemic rats, significantly (p<0.05) and (p<0.001), respectively at the 2nd h post dosing as compared to the control. In diabetic rats, the aqueous extract reduced blood triglycerides significantly (p<0.001) at the 2nd and 4th h post dosing. The effect of the methanolic extract was highly significant (p<0.001) but slower in its action, as it started at the 4th h. In conclusion, the bark of C. verum confirmed its traditional use in herbal medicine as an antidiabetic agent which can be more effective than the commonly used hypoglycaemic drugs. © Medwell Journals, 2010.

Saeed M.,Johannes Gutenberg University Mainz | Kuete V.,Johannes Gutenberg University Mainz | Kuete V.,University of Dschang | Kadioglu O.,Johannes Gutenberg University Mainz | And 4 more authors.
Phytomedicine | Year: 2014

A main problem in oncology is the development of drug-resistance. Some plant-derived lignans are established in cancer therapy, e.g. the semisynthetic epipodophyllotoxins etoposide and teniposide. Their activity is, unfortunately, hampered by the ATP-binding cassette (ABC) efflux transporter, P-glycoprotein. Here, we investigated the bisphenolic honokiol derived from Magnolia officinalis. P-glycoprotein-overexpressing CEM/ADR5000 cells were not cross-resistant to honokiol, but MDA-MB-231 BRCP cells transfected with another ABC-transporter, BCRP, revealed 3-fold resistance. Further drug resistance mechanisms analyzed study was the tumor suppressor TP53 and the epidermal growth factor receptor (EGFR). HCT116 p53-/-did not reveal resistance to honokiol, and EGFR-transfected U87.MG EGFR cells were collateral sensitive compared to wild-type cells (degree of resistance: 0.34). To gain insight into possible modes of collateral sensitivity, we performed in silico molecular docking studies of honokiol to EGFR and EGFR-related downstream signal proteins. Honokiol bound with comparable binding energies to EGFR (-7.30 ± 0.01 kcal/mol) as the control drugs erlotinib (-7.50 ± 0.30 kcal/mol) and gefitinib (-8.30 ± 0.10 kcal/mol). Similar binding affinities of AKT, MEK1, MEK2, STAT3 and mTOR were calculated for honokiol (range from -9.0 ± 0.01 to 7.40 ± 0.01 kcal/mol) compared to corresponding control inhibitor compounds for these signal transducers. This indicates that collateral sensitivity of EGFR-transfectant cells towards honokiol may be due to binding to EGFR and downstream signal transducers. COMPARE and hierarchical cluster analyses of microarray-based transcriptomic mRNA expression data of 59 tumor cell lines revealed a specific gene expression profile predicting sensitivity or resistance towards honokiol. © 2014 Elsevier B.V. All rights reserved.

Saeed M.,Johannes Gutenberg University Mainz | Khalid H.,Medicinal and Aromatic Plants Research Institute MAPRI | Sugimoto Y.,Keio University | Efferth T.,Johannes Gutenberg University Mainz
Phytomedicine | Year: 2014

(-)-Sesamin is a lignan present in sesam oil and a number of medicinal plants. It exerts various pharmacological effects, such as prevention of hyperlipidemia, hypertension, and carcinogenesis. Moreover, (-)-sesamin has chemopreventive and anticancer activity in vitro and in vivo. Multidrug resistance (MDR) of tumors leads to fatal treatment outcome in many patients and novel drugs able to kill multidrug-resistant cells are urgently needed. P-glycoprotein (MDR1/ABCB1) is the best known ATP-binding cassette (ABC) drug transporter mediating MDR. ABCB5 is a close relative to ABCB1, which also mediates MDR. We found that the mRNA expressions of ABCB1 and ABCB5 were not related to the 50% inhibition concentrations (IC50) for (-)-sesamin in a panel of 55 cell lines of the National Cancer Institute, USA. Furthermore, (-)-sesamin inhibited ABCB1- or ABCB5-overexpressing cells with similar efficacy than their drug-sensitive parental counterparts. In addition to ABC transporter-mediated MDR, we attempted to identify other molecular determinants of (-)-sesamin resistance. For this reason, we performed COMPARE and hierarchical cluster analyses of the transcriptome-wide microarray-based mRNA expression of the NCI cell panel. Twenty-three genes were identified, whose mRNA expression correlated with the IC50 values for (-)-sesamin. These genes code for proteins of different biological functions, i.e. ribosomal proteins, components of the mitochondrial respiratory chain, proteins involved in RNA metabolism, protein biosynthesis, or glucose and fatty acid metabolism. Subjecting this set of genes to cluster analysis showed that the cell lines were assembled in the resulting dendrogram according to their responsiveness to (-)-sesamin. In conclusion, (-)-sesamin is not involved in MDR mediated by ABCB1 or ABCB5 and may be valuable to bypass chemoresistance of refractory tumors. The microarray expression profile, which predicted sensitivity or resistance of tumor cells to (-)-sesamin consisted of genes, which do not belong to the classical resistance mechanisms to established anticancer drugs. © 2014 Elsevier GmbH.

Jaiswal R.,Jacobs University Bremen | Elsadig Karar M.G.,Jacobs University Bremen | Gadir H.A.,Medicinal and Aromatic Plants Research Institute MAPRI | Kuhnert N.,Jacobs University Bremen
Phytochemical Analysis | Year: 2014

Conclusion-It was possible to identify C-3 and C-7 flavonol glycosides by their order of elution and it was also possible to predict the glycosylation position in flavonol diglycosides from their tandem mass spectra. Copyright © 2014 John Wiley & Sons, Ltd.Introduction-Ixora coccinea L. leaves and stem are used in traditional Sudanese and Ayurvedic medicinal systems for the treatment of diarrhoea, fever, headache, skin diseases, eye trouble, wounds, sores and ulcers. Recent studies show that I. coccinea has anti-oxidant, anti-bacterial, anti-cancer, anti-inflammatory, analgaesic, anti-diarrhoeal, hepatoprotective, cardioprotective, antimutagenic, wound healing and anti-tumour activities. Ixora coccinea is a rich source of polyphenols such as proanthocyanidins, flavonoids, flavonoids glycosides and tannins. Objectives-To develop a LC-MSn method for the identification and characterisation of phenolic compounds of I. coccinea L. leaves and stem. Methods-Aqueous methanolic (70% methanol) extracts of I. coccinea leaves and stem were used for LC-MSn to ensure efficient extraction of phenolics. A C18 amide reverse-phase HPLC column allowed separation of the phenolic compounds, including different isomers. For the LC-MS measurements, negative ion mode was used in order to obtain better tandem mass spectra and high-resolution mass spectra. Results-The phenolics were identified by their typical UV absorptions at 254, 280 and 320 nm. All the flavonol glycosides showed a neutral loss of the glycan part; hydroxycinnamates showed loss of the cinnamoyl/cinnamic acid part; while proanthocyanidins showed a Diels-Alder fragment in negative ion mode mass spectra.

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