• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.305-308
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• 2012

• YAKHAK HOEJI
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• v.37 no.2
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• pp.198-203
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• 1993

Physico-chemical properties of methyl 5-hydroxy-dinaphtho[1,2-2',3'] furan-7,12-dione-6-carboxylate(MHDDC) were examined. The yellowish color of the solution at pH 8 below changes to a bluish color when the solution is basified to pH 10 above. This color change was presumed to a change of the molecular structure from a quinoid-type to a quinoid-type with the dissociation to the hydroxyl group as shown in chart 1.

• Archives of Pharmacal Research
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• v.21 no.2
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• pp.164-167
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• 1998

Bis-${\gamma}$-lactones (1,2) having a perhydrofuro[3,4-c]furan-1,4-dione skeleton were designed as conformationally constrained diacylglycerol analogues. They were synthesized from D-apiose in 11 steps, and evaluated as $PKC-{\alpha}$ ligands by measuring their ability to displace bound $^3H$]PDBU from the enzyme. The compounds showed moderate binding affinities with $K_i$ values of 13.89 (${\pm}5.67$) ${\mu}M$ and 11.47 (${\pm}0.89$) ${\mu}M$, respectively. Their similar binding affinities indicate that these two bicyclic compounds were not effectively discriminated by $PKC-{\alpha}$ in terms of the direction of the side chain as other ligands built on similar bis-${\gamma}$-lactones.

• Archives of Pharmacal Research
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• v.15 no.1
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• pp.52-57
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• 1992

The molecular structure of a natural compound was determined by single crystal X-ray diffraction analysis. The compound was isolated by methanol extraction and repeated chromatography from the stem of Paulownia tomentosa. Yellow prismatic crystals of the compound, which were recrystallized from tetrahydrofuran, are triclinic, with a = 7.310 (6), b = 10.753(6), c = 11.586(5) ${\AA}.\;\alpha= 93.30(6),\;\beta=105.62(10),\;\gamma=109.49(7)^\circ,\;D_x=1.514,\;D_m=1.51 g/cm^3$, space group P1 and Z = 2. The structure was solved by direct method, and refined by least-squares procedure to the final R-value of 0.032 for 1271 independent reflections $(F\le3\sigma{(F))}$. The compound is one of new furanquinone analogue. The molecule has a nearly planar conformation with an intramolecular hydrogen bond. In the crystal, the planar molecules are arranged as a prallel sheet-like pattern, and these stackings are stabilized by the O-H...O type intermolecular hydrogen bonds. The other intermolecular contacts appear to be the normal van der Waals interactions.

• Natural Product Sciences
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• v.18 no.1
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• pp.47-51
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• 2012

Among 38 Vietnamese medicinal plant extracts investigated for their ${\alpha}$-glucosidase inhibitory activity, 35 extracts showed $IC_{50}$ values below $250{\mu}g/mL$. The MeOH extracts of the heartwood of Oroxylum indicum, the seeds of Caesalpinia sappan, and the fruits of Xanthium strumarium exhibited strong ${\alpha}$-glucosidase inhibitory activity with $IC_{50}$ values less than $50{\mu}g/mL$. Fractionation of the MeOH extract of the heartwood of O. indicum led to the isolation of oroxylin A (1), oroxyloside (2), hispidulin (3), apigenin (4), ficusal (5), balanophonin (6), 2- (1-hydroxymethylethyl)-4H,9H-naphtho[2,3-b]furan-4,9-dione (7), salicylic acid (8), p-hydroxybenzoic acid (9), protocatechuic acid (10), isovanillin (11), and ${\beta}$-hydroxypropiovanillon (12). Compounds 1 - 3, 5, 6, 8, 10, and 12 showed more potent activities, with $IC_{50}$ values ranging from 2.13 to $133.51{\mu}M$, than a positive control acabose ($IC_{50}$, $241.85{\mu}M$). The kinetic study indicated that oroxyloside (2) displayed mixed-type inhibition with inhibition constant (Ki) was $3.56{\mu}M$.