Very strong proton deshielding was found in di/tri-aromatic isoxazoline regioisomers prepared from acridin-4-yl dipolarophiles and stable benzonitrile oxides (BNO). Three alkenes, (acridin-4-yl)-CH=CH-R (R = COOCH3, Ph, and CONH2), reacted with three BNO dipoles (2,4,6-trimethoxy, 2,4,6-trimethyl, 2,6-dichloro) to give pairs of target isoxazolines with acridine bound to C-4 or C-5 carbon of the isoxazoline (denoted as 4-Acr or 5-Acr). Regioselectivity was dependent on both the dipolarophile and dipole character. The ester and amide dipolarophile displayed variable regioselectivity in cycloadditions whereas the styrene one afforded prevailing 4-Acr regioisomers. 2,4,6-Trimethoxy-BNO was most prone to form 5-Acr isoxazolines while mesitonitrile oxide gave major 4-Acr isoxazolines. Basic hydrolysis of the amide cycloadduct led to an unexpected isoxazolone product. The structure of the target compounds was studied by NMR, MS, and X-ray crystallography.
Strong correlation was found between (13)C NMR chemical shifts of dipolarophilic CH=CH carbons and regioselectivity in 1,3-dipolar cycloadditions of new acridin-9-yl dipolarophiles with stable benzonitrile oxides (BNO). Accordingly, two starting dipolarophiles, (acridin-9-yl)-CH=CH-R (R = COOCH3 or Ph), reacted with three BNOs (2,4,6-trimethoxy, 2,4,6-trimethyl, and 2,6-dichloro) to give a mixture of two target isoxazoline regioisomers in which the acridine was bound either to isoxazoline C-4 carbon (4-Acr) or C-5 one (5-Acr). Methyl 3-(acridin-9-yl)propenoate afforded major 4-(acridin-9-yl)-isoxazoline-5-carboxylates (4-Acr) and minor 5-(acridin-9-yl)-4-carboxylates (5-Acr). 9-(2-Styryl)acridine regiospecifically afforded only 4-Acr cycloadducts. The ratios of regioisomers were compared with analogous reactions of acridin-4-yl dipolarophiles. Regioselectivity was dependent on a polarity of the CH=CH bond, donor effects in BNO, and stabilization by stacking of aromatic substituents in the products.
This research studies the influence of substrate on the antioxidant activity of alcohol extracts of Paecilomyces hepiali. We used corn, rice, millet, and peas as substrates. Antioxidant activity was measured with the DPPH radical scavenging method. Concentrations of extracts (6.25, 3.12, 1.56, 0.78, and 0.39 mg/mL) were applied in all evaluations. Overall antioxidant activity was expressed as the concentration of substrate that decreased DPPH radical levels by 50% (IC50DPPH) for 7 methanol and 7 ethanol extracts. A comparison of IC50DPPH allowed us to conclude that the methanol extracts are more active in scavenging stable DPPH radicals than are the ethanol extracts. The substrate with antioxidant properties most suitable for cultivation of P. hepiali was rice supplemented with non-defatted soy flour. The extract most effective in scavenging stable radicals was the methanol extract of sample 4 (IC50DPPH = 2.33 mg/mL) cultivated on rice with nondefatted soy flour. The methanol extract of sample 7 cultivated on peas was less effective (IC50DPPH = 11.50 mg/mL). By crystallizing these extracts, we managed to obtain sufficient quantities of 6 samples in a solid state, for which infrared spectra were measured and confirmed the presence of amino acids in the extracts.
The main component of Ophiocordyceps sinensis and Cordyceps militaris extracts are polysaccharides. These are natural biopolymers that represent a large class of biologically active components. These contribute to their pharmacological activity and effect on health. They contain monosaccharides that include rhamnose, ribose, arabinose, xylose, mannose, glucose, galactose, mannitol, fructose, and sorbose. The exopolysaccharide fraction has a large number of pharmacological effects, the two most important of which are immunomodulatory and antitumour. Among the contained polysaccharides is also mannoglucan, which shows weak cytotoxic activity against the SPC-I1) cancer cell line. More than ten nucleosides and their related compounds, including adenine, adenosine, inosine, cytidine, cytosine, guanine, uridine, thymidine, uracil, hypoxanthine, and guanosine, have been successively isolated from Ophiocordyceps sinensis. It contains many amino acids and polypeptides that are thought to affect the cardiovascular system. They also have a sedative and hypnotic effect, with tryptophan being the most effective component among them. Polysaccharides were extracted from four samples: sample 1 (grown on the substrate Oryza sativa indica, strain Ophiocordyceps sinensis), sample 2 (grown on the substrate Oryza sativa japonica, strain Ophiocordyceps sinensis), sample 3 (grown on the substrate Oryza sativa indica, strain Cordyceps militaris), sample 4 (grown on Oryza sativa japonica substrate, strain Cordyceps militaris). Through NMR spectroscopy and subsequent comparison with the literature, the majority of a chemical compound in deproteinized extracts 1 and 4 was found to be a hydrophilic polyglucan referred to as CBHP2).
Current research is focused on testing the cultivation of Paecilomyces hepiali mycelia on various plant substrates and producing fungus or mycelial biomass with qualitatively interesting substances. P. hepiali mycelia was cultivated using solid-state fermentation of different substrates. Mycelial biomass was then analyzed, and antioxidant activity was evaluated using the DPPH radical scavenging method for different ethanolic extracts based on a millet substrate (extract 1) or a chickpea substrate (extract 2). Extract 1 corresponds to a half-maximal DPPH radical inhibitory concentration of 1.73 mg/mL; the inhibitory concentration of ethanol extract 2 was almost 4.5 times higher at 7.92 mg/mL. Extracts 1 and 2 were separated into fractions by column chromatography and the chemical structures were determined for the substances that formed the most effective fraction of sample 1. The chemical structures of all compounds in the most active fraction of sample 1 were analyzed by 1H, 13C, distortionless enhancement by polarization transfer, correlation spectroscopy, heteronuclear single-quantum correlation spectroscopy, and heteronuclear multiple-bond correlation spectra.
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