Two previously undescribed cholestanol saponins from the rhizomes of Paris fargesii var. petiolata.

Two previously undescribed cholestanol saponins, parpetiosides F - G (1-2), and six known analogs (3-8) were isolated from the rhizomes of Paris fargesii var. petiolata. Their structures were elucidated by extensive spectroscopic data analysis and chemical methods. Compound 1 was a rare 6/6/6/5/5 fused-rings cholestanol saponin with disaccharide moiety linked at C-26 of aglycone which was hardly seen in genus Paris. All of these compounds were discovered in this plant for the first time. In addition, the cytotoxicities of saponins (1-8) against three human cancer cell lines (U87, HepG2 and SGC-7901) were evaluated by CCK-8 method, and saponins 5-8 displayed certain cytotoxicities. The strong interactions between saponins 5-8 and SCUBE3, an oncogene for glioma cells, were displayed by molecular docking.

Isolation, Purification and Characterization of a Novel Steroidal Saponin Cholestanol Glucoside from Lasiodiplodia theobromae that Induces Apoptosis in A549 Cells.

Search for novel anticancer lead molecules continues to be a major focus of cancer research due to the limitations of existing drugs such as lack of tumor selectivity, narrow therapeutic index and multidrug resistance of cancer types. Natural molecules often possess better pharmacokinetic traits compared to synthetic molecules as they continually evolve by natural selection process to interact with biological macromolecules. Microbial metabolites constitute nearly half of the pharmaceuticals in market today. Endophytic fungi, owing to its rich chemical diversity, are viewed as attractive sources of novel bioactive compounds. In the present study, we report the purification and characterization of a novel steroidal saponin, cholestanol glucoside (CG) from Saraca asoca endophytic fungus Lasiodiplodia theobromae. The compound was assessed for its cytotoxic potentialities in six human cancer cell lines, A549, PC3, HepG2, U251, MCF7 and OVCAR3. CG exhibited significant cytotoxicities towards A549, PC3 and HepG2 among which A549 cells were most vulnerable to CG treatment. However, CG treatment exhibited negligible cytotoxicity in non malignant human lung fibroblast cell line (WI-38). Induction of cell death by CG treatment in A549 cells was further investigated. CG induced the generation of reactive oxygen species (ROS) and mitochondrial membrane permeability loss followed by apoptotic cell death. Mitochondrial membrane depolarization and apoptotic cell death in CG treated A549 cells were completely blocked in presence of an antioxidant, N-acetyl cysteine (NAC). Hence it could be concluded that CG initiates apoptosis in cancer cells by augmenting the basal oxidative stress and that the generation of intracellular ROS is crucial for the induction of apoptosis.

Phallusiasterols A and B: two new sulfated sterols from the Mediterranean tunicate Phallusia fumigata and their effects as modulators of the PXR receptor.

Purification of the apolar extracts of the marine ascidian Phallusia fumigata, afforded two new sulfated sterols, phallusiasterols A (1) and B (2). The structures of the new compounds have been elucidated using mass spectrometry and NMR experiments. The effects of phallusiasterols A and B as modulators of pregnane-X-receptor (PXR) have been investigated. These studies revealed that phallusiasterol A induces PXR transactivation in HepG2 cells and stimulates the expression of the PXR target genes CYP3A4 and MDR1 in the same cell line. Molecular docking calculations suggested the theoretical binding mode of phallusiasterol A with hPXR and revealed that phallusiasterol A fitted well in the LBD of PXR.

Free Fatty acids and sterols in swine manure.

Free fatty acids and sterols were assessed in fresh manure and anaerobic lagoon sludge from swine production facilities in North Carolina. Eight free fatty acids and five sterols were identified and quantified in both manure and sludge samples. Compound identification was performed by gas chromatography/mass spectroscopy (GC-MS), and compound quantities were determined by gas chromatography after solid phase extraction with a 50:50 mixture of diethyl ether and hexane. The free fatty acids occurring in greatest abundance in both fresh manure and lagoon sludge were palmitic, oleic, and stearic. Free fatty acid content in fresh manure ranged from approximately 3 microg g(-1) dry weight (dw) to over 45 microg g(-1) dw. In lagoon sludge, free fatty acid content ranged from about 0.8 microg g(-1) dw to nearly 4 microg g(-1) dw. Coprostanol and epicoprostanol were the sterols in largest concentrations in fresh manure and lagoon sludge samples. Total sterol content ranged from approximately 0.5 microg g(-1) dw to around 11 microg g(-1) dw in fresh manure and from 3.5 microg g(-1) dw to almost 9 microg g(-1) dw in lagoon sludge. Fresh manure and lagoon sludge both had high levels of inorganic cations (e.g., Ca, Mg, Fe) capable of binding free fatty acids and forming insoluble complexes, thereby potentially reducing fatty acid biodegradation. In anaerobic lagoons, sterols are an organic fraction of sludge that are resistant to bacterial degradation. In the case of fresh manure, fatty acids could represent a potential source of energy via the manufacture of biodiesel fuel, if efficient means for their extraction and transesterification can be devised.

An efficient diethyl ether-based soxhlet protocol to quantify faecal sterols from catchment waters.

A study was conducted to evaluate the efficiency and reproducibility of a diethyl ether-based soxhlet extraction procedure for faecal sterols occurring from catchment waters. Water samples spiked with a mixture of faecal sterols were filtered and analytes were extracted using the diethyl ether-based soxhlet method and the Bligh and Dyer chloroform extraction process. For diethyl ether-based soxhlet extraction procedure, solvent extracts were saponified with 100 microL of 10% KOH in methanol (100 degrees C/120 min) and then acidified with 60 microL of 6M HCl. Lipid contents were extracted by ethanol (0.5 mL) from the saponification products. The lipid extracts were then reacted with 100 microL of bis(trimethyl)trifluoroacetamide (BSTFA) containing 1% trimethyl chlorosilane (100 degrees C/60 min) to form the trimethylsilyl (TMS) derivatives. The derivatised extracts were then analyzed by gas chromatography-mass spectrometry. For sterol concentrations ranging from 35 to 175 microg mL(-1), the soxhlet-based extraction process yielded the following recovery efficiencies for coprostanol (101%), epicoprostanol (97%), cholesterol (97%), dihydrocholesterol (97%) and 5alpha-cholestane (111%), whereas the Bligh and Dyer process yielded recoveries of 32, 41, 0, 36 and 51%, respectively. The results suggested that the diethyl ether-based soxhlet extraction method was more efficient and reproducible than the Bligh and Dyer chloroform extraction process for the analyses of trace levels of faecal sterols from water samples. Moreover, it was revealed that the diethyl ether-based soxhlet extraction method used less solvent and was logistically easier.

High-performance liquid chromatographic method for isolating coprostanol from sediment extracts.

We report a rapid, largely automated high-performance liquid chromatographic (HPLC) method, which uses an HPLC column packed with alkylnitrile-substituted secondary alkylamine (aminocyano) bonded phase, to isolate coprostanol from interfering compounds in sediment extracts. Coprostanol is then quantitated, as the trimethylsilyl ether, by gas chromatography with flame ionization detection. Results from using the HPLC method to analyze a sediment reference material for coprostanol were statistically comparable to a previously used gravity-flow column method. We also report the coprostanol concentrations in several sediment samples from the California coast which reflect a range of sewage contamination (62-15,000 ng/g).

Minor and trace sterols in marine invertebrates. 62. Novel coprostanols with unusual side chains from the marine sponge Calyx nicaeensis.

Seventeen stanols with a variety of unusual side chains and possessing the rare 5 beta-dihydro nucleus have been isolated from the sponge Calyx nicaeensis. These stanols probably result from bacterial metabolism of the endogenous sponge sterols.

Minor and trace sterols from marine invertebrates 56. Novel coprostanols from the marine sponge Petrosia ficiformis.

Twelve stanols possessing the rare 5 beta-dihydro nucleus have been isolated from the marine sponge Petrosia ficiformis. These stanols have not previously been encountered in any samples of P. ficiformis which we have examined and appear to be the result of bacterial metabolism of the endogenous sponge sterols.