Two new megastigmane glycosides from the leaves of Nicotiana tabacum and their anti-inflammatory activities.

Two new megastigmane glycosides, (6 R,7E,9R)-3-oxo-α-ionyl-9-O-α-L-rhamnopyranosyl-(1''→4')-ß-D-glucopyranoside (1) and (6 R,7E,9R)-3-oxo-α-ionyl-9-O-ß-D-glucopyranosyl-(1''→6')-ß-D-glucopyranoside (2), together with six known analogues (3-8) were isolated from the leaves of Nicotiana tabacum. The structures of all metabolites were determined by comprehensive analysis of NMR and MS spectroscopic data as well as by comparison with those of previously reported. The in vitro anti-inflammatory activity of all isolates was evaluated using a lipopolysaccharide (LPS)-induced RAW264.7 cell inflammatory model, and the compounds 1, 3, 7, and 8 exhibited inhibition of LPS-induced NO production in RAW264.7 macrophage cells with IC50 values of 42.3-61.7 µM (positive control, dexamethasone, IC50 = 21.3 ± 1.2 µM).

New Caffeoylquinic Acid Derivatives and Flavanone Glycoside from the Flowers of Chrysanthemum morifolium and Their Bioactivities.

The Chrysanthemum morifolium flower is widely used in China and Japan as a food, beverage, and medicine for many diseases. In our work, two new caffeoylquinic acid derivatives (1, 2), a new flavanone glycoside (3), and six reported flavanones (4⁻9) were isolated and identified from the flowers of C. morifolium. The chemical structures of all isolates were elucidated by the analysis of comprehensive spectroscopic data as well as by comparison with previously reported data. The isolated constituents 1⁻8 were evaluated for their neuroprotective activity, and compounds 3 and 4 displayed neuroprotective effects against hydrogen peroxide-induced neurotoxicity in human neuroblastoma SH-SY5Y cells.

A new family-3 glycoside hydrolase from Penicillium oxalicum BL 3005 catalyzing tyrosol glucosylation to form salidroside.

A glycoside hydrolase from Penicillium oxalicum BL 3005 was purified to apparent homogeneity. Its molecular mass was estimated to be 90 kDa by SDS-PAGE. The enzyme was identified to be a new member of family-3 by peptide sequence. High transglycosylation activity was found in the hydrolytic reaction of cellobiose. In the reaction, salidroside (4-hydroxyphenethyl O-ß-d-glucopyranoside) was formed by adding tyrosol as the glycosyl acceptor. The optimum reaction pH and temperature were pH 6.5 and 55 °C, respectively. The maximum yield of salidroside was almost 20 g/L. These results indicated that the ß-glucosidase of P. oxalicum can be considered as a very promising catalyst for the synthesis of salidroside.

Bioconversion of lutein to form aroma compounds by Pantoea dispersa.

OBJECTIVES: To investigate the conversion of lutein, a carotenoid, to aroma compounds by Pantoea dispersa Y08, a lutein-degrading bacterium isolated from marigold flower residue. Bioconversion conditions, including substrate concentration, applied co-solvent and reaction time, were optimized. RESULTS: A maximum biodegradation yield of 80 % for lutein at 10 g/l was achieved. The intermediate, 3-hydroxy-ß-ionone, and final ß-ionone products were revealed by GC-MS. A bioconversion pathway of lutein is proposed to involve cleavage at the 9-10 double bond position, followed by de-hydroxylation at the 3-hydroxy position. CONCLUSIONS: This is the first report of the ability of a bacterium, P. dispersa, to sequentially convert lutein to 3-hydroxy-ß-ionone and then ß-ionone.

Optimization of exopolysaccharide production in submerged culture of Daedalea dickinsii and its antioxidant activity.

The major nutrients, pH and temperature were evaluated for the exopolysaccharide (EPS) production by Daedalea dickinsii in submerged culture to derive an optimal medium composition and conditions as follows: 50 g/L maltose, 5 g/L soy peptone, 5 mM CaCl(2), at pH 6.0 and 28 °C. A purified EPS fraction was attained from gel filtration chromatography and its major molecular characteristics were determined. FT-IR spectral analysis revealed the prominent characteristic groups of polyhydric alcohols. GC analysis and NMR spectrum showed its major molecular composition of glucose and galactose. Furthermore, thermogravimetric analysis indicated its degradation temperature (T(d)) of 189 °C. The antioxidant activity of the EPS fraction showed a correlation with the molecular properties. It might be attributed to the functional groups in the EPS fraction, which can donate electrons to reduce the radicals to a more stable form or react with the free radicals to terminate the radical chain reaction.

Antioxidant activity potential of Virginia (flue-cured) tobacco flower polysaccharide fractions obtained by ultrasound-assisted extraction.

Ultrasound-assisted extraction was employed to extract polysaccharide from Virginia (flue-cured) tobacco flowers. The orthogonal matrix method (L9(3)(4)) was used to determine the optimal extraction conditions as to ultrasound power, extraction time, ratio of solvent to solid, and extraction temperature at 300 W, 4 min, 35 (mL/g), and 70 °C respectively. The crude extract was successively purified by chromatography, yielding two major polysaccharide fractions, termed Fr-I and Fr-II. Both fractions are heteropolysaccharides, mainly containing glucose, mannose, and allose with an a-configuration. Thermo gravimetric analysis (TGA) indicated that the degradation temperatures (Td) of Fr-I and Fr-II were 185 °C and 190 °C respectively. The preliminary antioxidant activity test in vitro showed both fractions could potentialize the scavenging effect on hydroxyl and DPPH radicals in a dose-dependent manner. In conclusion, the two polysaccharides may be useful as naturally potential antioxidant agents for application in food and medicinal fields.

Pyrroloquinoline quinone biosynthesis in Escherichia coli through expression of the Gluconobacter oxydans pqqABCDE gene cluster.

We have expressed the pqqABCDE gene cluster from Gluconobacter oxydans, which is involved in pyrroloquinoline quinone (PQQ) biosynthesis, in Escherichia coli, resulting in PQQ accumulation in the medium. Since the gene cluster does not include the tldD gene needed for PQQ production, this result suggests that the E. coli tldD gene, which shows high homology to the G. oxydans tldD gene, carries out that function. The synthesis of PQQ activated d-glucose dehydrogenase in E. coli and the growth of the recombinant was improved. In an attempt to increase the production of PQQ, which acts as a vitamin or growth factor, we transformed E. coli with various recombinant plasmids, resulting in the overproduction of the PQQ synthesis enzymes and, consequently, PQQ accumulation--up to 6 mM--in the medium. This yield is 21.5-fold higher than that obtained in previous studies.

4,4'-(Anthracene-9,10-di-yl)dibenzoic acid dimethyl-formamide disolvate.

In the title compound, C(28)H(18)O(4)·2C(3)H(7)NO, the dihedral angle between the benzene rings and the anthracene system is 74.05 (12)°. A crystallographic inversion centre is located in the middle of the anthracene unit. The dimethyl-formamide solvent mol-ecules are partially disordered over two positions of approximately equal occupancy [0.529 (6):0.471 (6)]. Inter-molecular O-H⋯O hydrogen bonds with the major occupancy formamide O atom as acceptor result in the formation of 2:1 solvate-complex aggregates, which are alternately linked to shorter solvate units via weak inter-molecular C-H⋯O contacts generated from the rotational disorder of the formamide O atom (minor occupancy component). Weak C-H⋯π inter-actions between the solvent mol-ecules as the donor and the outer anthracene rings support these contacts in the crystal structure for both disorder components.

4-(2,5-Dihexyl-oxyphen-yl)benzoic acid.

In the title compound, C(25)H(34)O(4), one n-hexyl chain of the hex-yloxy group adopts a fully extended all-trans conformation, and the other n-hexyl chain displays disorder with site occupancies of 0.470 (3) and 0.530 (3). The dihedral angle between the benzene rings is 44.5 (3)°. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds form dimers via crystallographic inversion centres.