Isolation, biological evaluation and validated HPTLC-quantification of the marker constituent of the edible Saudi plant Sisymbrium irio L.

AbstractPhytochemical investigation and chromatographic purification of the n-hexane fraction of the aerial parts of the edible Saudi plant Sisymbrium irio led to the isolation of β-sitosterol (1), stigmasterol (2) and β-sitosterol-β-d-glucoside (3). The cytotoxic effects of the n-hexane, dichloromethane, ethyl acetate and n-butanol fractions were tested against three cancer cell lines viz., MCF-7, HCT-116 and HepG2, using the crystal violet staining (CVS) method, while the antibacterial activity against a number of pathogenic bacterial strains, was also estimated using the broth microdilution assay. The n-hexane fraction showed potent cytotoxic activities against all tested human cancer cell lines (IC50: 11.7–13.4μg/mL), while the dichloromethane fraction was particularly potent against HCT-116 cells (IC50: 5.42μg/mL). On the other hand, the n-hexane and EtOAc fractions demonstrated significant inhibitory activities against the Gram positive bacteria S. pyogenes and C. perfringens; and the Gram negative bacterium S. enteritidis. Our results warrant the therapeutic potential of S. irio as nutritional supplement to reduce the risk of contemporary diseases. Additionally, a validated high performance thin-layer chromatography (HPTLC) method was developed for the quantitative analysis of biomarker β-sitosterol glucoside (isolated in high quantity) from the n-hexane fraction. The system was found to furnish a compact, sharp, symmetrical and high resolution band for β-sitosterol glucoside (Rf=0.43±0.002). The limit of detection (LOD) and limit of quantification (LOQ) for β-sitosterol glucoside was found to be 21.84 and 66.18ngband−1, respectively. β-sitosterol glucoside was found to be present only in n-hexane fraction (2.10μg/mg of dried fraction) while it was absent in the other fractions of S. irio which validated the high cytotoxic and antibacterial activity of n-hexane fraction of S. irio

Screening of Anti-Mycobacterium smegmatis Actinomycetes from Special Habitats and the Preliminary Study of a Positive Strain

随着陆生放线菌资源不断被发掘和深入研究，常规发酵方法下所得到的次生代谢产物资源越来越稀少，为新药发现造成阻碍。目前，很多学者已经把目光投向了一些特殊生境中的放线菌，包括海洋、动植物内生和一些极端环境。近些年来，由于耐药结核菌（XDR-TB，MDR-TB）的产生和传播，使全球范围的结核病疫情有上升趋势。耐药菌株对临床上常用的利福平等药物已产生严重耐药性，近五十年未发现新靶点的抗结核临床一线药物。因此，寻找具有抗结核分枝杆菌活性的新化合物仍是制药领域所迫切需要的。而特殊生境中的放线菌次生代谢产物在结构和生物活性方面具有丰富多样性，是寻找新型抗结核药物的潜力资源。 因为许多药物类似物对靶点发挥抑制...Along with terrestrial actinomycetes resources are constantly being discovered and in-depth studied, the secondary metabolite resources produced by conventional fermentation become increasingly scarce. These are obstacles for the discovery of new drugs in pharmaceutical industry. At present, many scholars have focused on the actinomycetes from special habitats, including marine, animal and plant e...学位：理学硕士院系专业：生命科学学院生物学系_微生物学学号：2172009115213

Two New Secondary Metabolites from the Endophytic Fungus Endomelanconiopsis endophytica

Two new secondary metabolites, endomeketals A–B (1–2), a new natural product (3), and a known compound (4) were isolated from the ethyl acetate extract of the endophytic fungus Endomelanconiopsis endophytica A326 derived from Ficus hirta. Their structures were determined on the basis of extensive spectroscopic analysis. All compounds were evaluated for their cytotoxic activities against SF-268, MCF-7, NCI-H460, and HepG-2 tumor cell lines. However, no compound showed cytotoxic activity against these human tumor cell lines

Perangustols A and B, a pair of new azaphilone epimers from a marine sediment-derived fungus <i>Cladosporium perangustm</i> FS62

<p>A pair of new azaphilone epimers, perangustols A-B (<b>1</b>–<b>2</b>), and two new natural products (<b>3</b>–<b>4</b>), together with two known metabolites (<b>5</b>–<b>6</b>) were isolated from the culture of the marine sediment-derived fungus <i>Cladosporium perangustum</i> FS62. The structures of these compounds were established on the basis of extensive spectroscopic analysis. The isolated compounds (<b>1</b>–<b>6</b>) were evaluated for their cytotoxic activities against the SF-268, MCF-7, NCI-H460, and HepG-2 tumor cell lines. Nonetheless, no significant activity was observed.</p

Preliminary Study on Hepatocyte-Targeted Phosphorus-31 MRS Using ATP-Loaded Galactosylated Chitosan Oligosaccharide Nanoparticles

Background. The clinical applications of hepatic phosphorus-31 magnetic resonance spectroscopy (31P MRS) remain to be difficult because the changes of phosphates between normal hepatic tissues and pathological tissues are not so obvious, and furthermore, up to now there is few literature on hepatocyte-targeted 31P MRS. Materials and Methods. The ATP-loaded Gal-CSO (Gal-CSO/ATP) nanoparticles were prepared and the special cellular uptake of them as evaluated by using HepG-2 tumor cells and A549 tumor cells, respectively. Two kinds of cells were incubated with the nanoparticles suspension, respectively. Then were prepared the cell samples and the enhancement efficiency of ATP peaks detected by 31P MRS was evaluated. Results. The cellular uptake rate of Gal-CSO/ATP nanoparticles in HepG-2 cells was higher than that in A549 cells. Furthermore, the enlarged ATP peaks of Gal-CSO/ATP nanoparticles in HepG-2 cells were higher than those in A549 cells in vitro detected by 31P MRS. Conclusions. Gal-CSO/ATP nanoparticles have significant targeting efficiency in hepatic cells in vitro and enhancement efficiency of ATP peaks in HepG-2 cells. Furthermore, 31P MRS could be applied in the research of hepatic molecular imaging

A Probe for the Detection of Hypoxic Cancer Cells.

Hypoxia is a common feature of tumor cells. Nitroreductase (NTR), a common biomarker of hypoxia, has been widely used to evaluate the extent of tumor hypoxia. In this study, three fluorescent probes (FBN-1-3) were synthesized to monitor the extent of hypoxia in cancer cells in real time. FBN-1-3 were composed of a fluorescein analogue and one of three different aromatic nitro groups. Of these probes, FBN-1 showed excellent sensitivity and selectivity in detecting hypoxia via a reduction in O2 concentration. Confocal fluorescence imaging and flow cytometry demonstrated that HepG-2, A549, and SKOV-3 cells incubated with FBN-1 under reduced oxygen conditions showed significantly enhanced fluorescence. A mouse HepG-2 tumor model confirmed that FBN-1 responds rapidly to NTR and can be used to evaluate the degree of tumor hypoxia. The changes in intra- and extracellular NTR in tumor cells were also concurrently monitored, which did not reveal a link between NTR concentration and degree of hypoxia. Our work provides a functional probe for tumor hypoxia, and our results suggest the fluorescent response of our probe is due to a decrease in O2 concentration, and not NTR concentration

Anticancer Potency of Platinum(II) Complexes Containing Both Chloride Anion and Chelated Carboxylate as Leaving Groups

Three platinum complexes with both a chloride anion and a chelated carboxylate as leaving groups were synthesized and spectrally characterized. In vitro cytotoxicity of complexes <b>1</b>–<b>3</b> was evaluated against human A549, HCT-116, MCF-7, and HepG-2 tumor cell lines. The results showed that all the compounds exhibited effective cytotoxicity against the tested cell lines, nearly comparable to those of cisplatin and oxaliplatin. Notably, the activity of complex <b>2</b> was about 2-fold better than that of oxaliplatin against the HCT-116 cell line. Flow cytometry analysis indicated that these complexes produced death of tumor cells through an apoptotic pathway. The DNA-binding properties of the platinum-based compounds were also studied by agarose gel electrophoresis. The kinetics study showed that the chloride anion departs from the Pt atom quickly, whereas the five and/or six-membered ring formed by coordination of N,O-donors and the metal ion is opened a little more slowly by the rupture of a Pt–O bond, which helps us to further understand the mechanism of action of the newly synthesized complexes with biomolecules. Furthermore, the reaction rate constants of complexes <b>1</b>–<b>3</b> were roughly the same