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[en] Neferine, an alkaloid isolated from Lotus seeds, displays multiple pharmacological effects that counter cancer, oxidants, and arrhythmia. It was initially identified as a strong inducer for macroautophagy in cancer cells by suppressing AMPK/mTOR signaling. In this study, we found that autophagy signaling was inhibited in the condition of neferine treatment. Exposure to neferine resulted in the accumulation of LC3-II and an associated adaptor protein, p62/SQSTM1. Knockdown of ATG5 failed to reduce the accumulation of LC3-II induced by neferine. The electron microscopy (EM) images showed that neferine induce accumulation of multi-vesicle bodies (MVB) and failure of lysosome maturation. Moreover, exposure to neferine reduced maturation of cathepsin D and impaired the degradation of autophagic and phagocytic cargos. Rather than stimulate autophagic flux, the data indicate that neferine impaired lysosomes to block degradation within phagolysosomes.
[en] Highlights: • Overexpression of SlH6H or HnH6H significantly promoted the anisodamine production at similar level. • Overexpression of SlH6H or HnH6H markedly enhanced the scopolamine biosynthesis at different level. • HnH6H exhibited better effects on the enhancement of scopolamine biosynthesis than SlH6H. • Overexpression of HnH6H led to the increased production of total tropane alkaloids. Scopolia lurida, a medicinal plant native to the Tibetan Plateau, is among the most effective producers of pharmaceutical tropane alkaloids (TAs). The hyoscyamine 6β-hydroxylase genes of Hyoscyamus niger (HnH6H) and S. lurida (SlH6H) were cloned and respectively overexpressed in hairy root cultures of S. lurida, to compare their effects on promoting the production of TAs, especially the high-value scopolamine. Root cultures with SlH6H/HnH6H overexpression were confirmed by PCR and real-time quantitative PCR, suggesting that the enzymatic steps defined by H6H were strongly elevated at the transcriptional level. Tropane alkaloids, including hyoscyamine, anisodamine and scopolamine, were analyzed by HPLC. Scopolamine and anisodamine contents were remarkably elevated in the root cultures overexpressing SlH6H/HnH6H, whereas that of hyoscyamine was more or less reduced, when compared with those of the control. These results also indicated that SlH6H and HnH6H promoted anisodamine production at similar levels in S. lurida root cultures. More importantly, HnH6H-overexpressing root cultures had more scopolamine in them that did SlH6H-overexpressing root cultures. This study not only provides a feasible way of overexpressing H6H to produce high-value scopolamine in engineered root cultures of S. lurida but also found that HnH6H was better than SlH6H for engineering scopolamine production.
[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] This review focuses on the role of the nitrogen-oxygen bond as a structural cornerstone for the construction of complex natural products. This bond may play several roles such as a functional protecting group or an activating group in carbonyl chemistry. Compounds containing a N-O bond are generally prepared by cycloaddition of nitroso derivatives, nitrones or nitriles oxides. The first two reactions have been used in the synthesis of a N-O bond containing natural product, pyrinodemin A, or for the synthesis of hydroxylated piperidine alkaloids after N-O bond cleavage. (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] This mini review is devoted to an interesting group of natural terpenoids called highly oxygenated isoprenoid lipids (HOIL). Their producers are microorganisms, as well as they are found in plants, fungi, animals and marine organisms. The present review consists of three parts. For all three groups of HOIL presented, the chemical structure and the calculated biological activity are given. The first is an overview of HOIL found in nature with a description of some of the pharmacological properties and activity. For the first group of terpenoids, the most characteristic activities are anti-seborrheic, antineoplastic, and anti-inflammatory, and they can be used as ovulation inhibitors with a certainty of 85 to 91 percent. In the second part, we present an interesting group of heterocyclic HOIL (or steroidal alkaloids) found in nature with an indication of their possible activity. For the second group of HOIL, the most characteristic activities are: hypolipemic, antifungal, and antineoplastic, and they can be used as lipid metabolism regulators with a confidence of 81 to 89 percent. And in the third group, we represent HOIL derived from marine microorganisms and invertebrates. For the third group of HOIL, the most characteristic activities are: antineoplastic and antipsoriatic and they can be used as cytochrome P450 inhibitors and hepatoprotectants with a confidence of 77 to 93 percent. (author)
[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] Two quinolinone alkaloids, N-methylflindersine (1), flindersine (2) and two acylphloroglucinols, evodionol (3), methylevodionol (4) were isolated from the leaves of Melicope denhamii. Structures of compounds were elucidated using spectroscopic methods such as UV, IR, HRESIMS, 1D and 2D NMR. Compounds 1-4 were evaluated for their cytotoxicity against P-388 cells, compound 2 showed moderate activity with IC50 4.86 μg/ml. (paper)