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[en] Plasma bromocriptine assays must have high sensitivity because plasma concentrations are low, and high specificity because bromocriptine is extensively metabolised. This paper describes the simple preparation of a radioiodine-labelled derivative of dihydroergocriptine and its use in a radioimmunoassay employing an antiserum directed against the intact bromocriptine molecule. The method could measure plasma bromocriptine at concentrations of 0.05 nmol/L, had between-assay coefficients of variation of less than 10% and was more convenient than previous assays using tritium radiolabels. (author)
[en] Annona Muricata belongs to the family Annonaceae which is known to have anticancer, anti-inflammatory and many other bio activities. Leaves, twig, fruit and seed of A. muricata were collected from Suhan Biotech and dried. Hot and cold aqueous extracts were prepared for the preliminary screening of phytochemicals and aqueous extracts of A. muricata were evaluated for total phenolic, scavenging assay (DPPH; 1-1-diphenyl-2-picrylhydrazyl) and cytotoxic activities. Phytochemicals screening of leaves extracts revealed the presence of alkaloids, terpenoid, reducing sugar, carbohydrate and anthocyanins. While for twig extracts it revealed the presence of coumarine. Antra quinones, terpenoid, flavonoid, reducing sugar, lipids and coumarine were found in fruit and seed extracts. The total phenolic content was found to be 2.372±0.922 μg GAE/ g, 85.85±6.23 μg GAE/ g, 53.56±8.39 μg GAE/ g and 54.67±13.33 μg GAE/ g for leaves, twig, fruit and seed respectively. On the other hand, all extract have showed IC_5_0 value more than 500 μg/ mL in DPPH scavenging assay. Cytotoxic evaluation of all extracts against HTB43, MCF-7 and MDAMB231 cell lines showed IC_5_0 value more than 250 μg/ mL. In conclusion, the results showed that aqueous extract of A.muricata was inappropriate as anticancer agen (author)
[en] A study on the interaction of benzophenanthridine plant alkaloid chelerythrine (CHL) with low pH induced protonated form and conventional B-form DNA was carried out by using a combination of various spectroscopic and viscometric techniques. The interaction of the alkaloid with protonated form of DNA was characterized by the typical hypochromic and bathochromic shifts in the absorption spectrum, increase of thermal melting temperature, increase in solution viscosity, perturbation in circular dichroic spectrum. Binding constant for the association of CHL with protonated DNA was of the order of 105 M−1. The mode of binding of CHL with protonated DNA was characterized from the absorption spectral studies, viscosity measurements and quenching experiments. The stabilization of protonated DNA upon binding with CHL was revealed from thermal melting studies. CD spectral studies revealed that CHL converted the protonated form of CT-DNA to the right handed B-form.
[en] Oxypalmatine and oxypseudopalmatine were synthesized in three steps from the benzonitrile 11 and toluamides 12a, b. The lithiated cycloaddition reaction yielded 3-arylisoquinolinone intermediates. A subsequent internal SN2 reaction produced the corresponding 8-oxoprotoberberines, oxypalmatine and oxypseudopalmatine
[en] Tetrahydroquinolines bearing substituents are frequently found as a substructure in a number of alkaloids and natural products. Since their individual stereoisomers displays different biological activities, it is desirable to develop a highly stereoselective synthetic method for tetrahydroquinolines. While some progress has recently been made toward the development of asymmetric synthetic methods for tetrahydroquinolines, it is still a challenging topic in organic synthesis. In order to investigate the source of diastereoselection attained in the substitution reaction with a racemic epoxide, we examined the substitution of 2 with an excess amount of racemic p-chlorophenyl-substituted oxirane. We have developed a novel method for the asymmetric synthesis of trans-3,4-diaryl-substituted tetrahy- droquinolines from ortho-substituted N-pivaloyl anilines. The enantioselective process includes (+)-sparteine-mediated stereoselective lithiati on, kinetic resolution of epoxides in substitution, and stereospecific Mitsu nobu cyclization as the key reactions. The simple protocol can provide highly functionalized tetrahydroqu inoline rings and would allow their further functionalization to access more complex target molecules
[en] Mutagenicity testing of alcoholic extracts of irradiated and control potatoes and of pure phenolic and alkaloidal compounds, known to exist in potato tubers was completed. No evidence of mutagenic effects in the Ames test was observed for either extracts of irradiated (0.1, 0.5 and 3 kGy) or non-irradiated tubers in the TA 100 and TA 98 strains with and without addition of microsomal liver enzymes. Further, solanidine, solanine, coumarin, umbelliferon, exculetin scopoletin, chlorogenic and, caffeic acid, ferulic acid, o-coumaric acid and p-coumaric acid were negative under similar conditions (till 200 μg/plate). (Auth.)
[en] Complete text of publication follows. Berberine and palmatine are two important members of quaternary protoberberine alkaloids. Their salts exist in many Chinese herbal medicines, such as Rhizoma coptidis and Caulis mahoniae. The ability of some protoberberine alkaloids to act as topoisomerase II poisons is linked to their anticancer activity. These alkaloids possessing also antimicrobial, antidiarrheal and cardiovascular activities, are useful for the development of more efficient DNA-binding agents. The aim of our study was to investigate the influence of binding to DNA on physicochemical properties of these drugs. Binding properties have been studied using absorption, emission, DNA melting, viscometric and fluorescence polarization experiments. The results indicate partial intercalation of both alkaloids into DNA helix, leading to enhanced fluorescence quantum yield and longer lifetimes of the excited state. No berberine phosphorescence or T-T absorption were observed in the aqueous solution. Once bound to DNA, photoexcitation of berberine at 351 nm by laser pulse, leads to the triplet state with high efficiency. The triplet is detected by its transient absorption, with maxima at 425 nm and 560 nm. Its deactivation occurs in the millisecond timescale. Using pulse radiolysis we recorded absorption spectra of reduced and oxidized forms of alkaloids in aqueous solutions. The same intermediates as in the case of aqueous solutions are formed for the reduction by hydrated electron of drugs intercalated into DNA. We have found that the reaction of hydrated electrons with the scavenger molecules residing in the potential field of negatively charged DNA is strongly inhibited. Preliminary results on degradation DNA by ionizing radiation in the presence of berberine and palmatine will also be discussed.
[en] Deuterium labelled analogues of ajmalicine, yohimbine, tabersonine and catharanthine were synthesized by base catalyzed transesterification of the methyl group in deuterated methanol. (author)
[en] Leptadenia pyrotechnica (Forssk.) Decne is a medicinal plant that is native to hot deserts of Pakistan. This plant is sporadically known with reference to bioactivity including phytochemical screening especially from Pakistan. The present study was designed to screen out four major groups of phytochemicals such as alkaloids, flavonoids, saponins and tannins from eight solvents based roots and aerial parts extracts viz., hexane, chloroform, acetone, ethyl acetate, butanol, ethanol, methanol and water of the selected plant. The qualitative screening showed the presence of all major groups of phytochemicals in both plant parts extracts in which methanolic ones were the most efficient that extracted all the selected classes of phytochemicals. Quantitative screening revealed various concentrations of selected phytochemicals in both plant parts. The alkaloid contents were 3.267±0.643and 3±0.6 in roots and aerial parts respectively (p>0.05). The total flavonoid content was 76.867±2.266 and 139.448±8.677 QE/100g in roots and aerial parts respectively. In the case of total saponin contents, the proportions were 0.34±0.013% and 0.4 0.010% in roots and aerial parts respectively, whereas; total tannin contents were 62.713±4.841 and154.961±5.853 mg of TAE/100g of extract in roots and aerial parts, respectively. This study will serve as a benchmark for further pharmacological studies on the said plant that may be harnessed for drug development in the future. (author)
[en] The photoreactivity of dictamnine, a furoquinoline alkaloid, towards different synthetic DNAs has been studied. The ratio of the photobinding of [3H]-dictamnine to poly(dA-dT).poly(dA-dT):poly(dG-dC).poly(dG-dC):poly(dA-dU).poly(dA-dU):poly(dA).poly(dT), in relation to that of calf thymus DNA, is 18:1:0.5:0.3. Prior treatment of calf thymus DNA with dictamnine in light inhibits the subsequent incorporation of 8-methoxypsoralen (8-MOP). These results suggest that the sites in DNA for the photobinding of dictamnine are probably identical with those for monoadducts of 8-MOP. Furthermore, the template activity of photomodified DNA in the RNA polymerase reaction is considerably inhibited for poly(dA-dT).poly(dA-dT), to a lesser extent for calf thymus DNA, but almost not affected for the linear copolymer, poly(dA).poly(dT). (author)