Crystal structure of tetra-hydro-seselin, an angular pyran-ocoumarin.

In the title compound, tetra-hydro-seselin, C14H16O3, a pyran-ocoumarin [systematic name: 8,8-dimethyl-3,4,9,10-tetra-hydro-2H,8H-pyrano[2,3-f]chromen-2-one] obtained from the hydrogenation of seselin in the presence of Pd/C in MeOH at room temperature, the dihedral angle between the central benzene ring and the best planes of the outer fused ring systems are 6.20 (7) and 10.02 (8)°. In the crystal, mol-ecules show only very weak inter-molecular C-H⋯O inter-actions.

Crystal structure of di-bromo-meth-oxy-seselin (DBMS), a photobiologically active pyran-ocoumarin.

The title compound, C15H14Br2O4 [systematic name: rac-(9S,10R)-3,9-dibromo-10-methoxy-8,8-dimethyl-9,10-dihydropyrano[2,3-h]chromen-2(8H)-one], is a pyran-ocoumarin derivative formed by the bromination of seselin, which is a naturally occurring angular pyran-ocoumarin isolated from the Indian herb Trachyspermum stictocarpum. In the mol-ecule, the benzo-pyran ring system is essentially planar, with a maximum deviation of 0.044 (2) Šfor the O atom. The di-hydro-pyran ring is in a half-chair conformation and the four essentially planar atoms of this ring form a dihedral angle of 4.6 (2)° with the benzo-pyran ring system. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds, forming chains propagating along [010]. In addition, π-π stacking inter-actions, with centroid-centroid distances of 3.902 (2) and 3.908 (2) Å, link the hydrogen-bonded chains into layers parallel to (001).

Crystal structure of a photobiologically active brominated angular pyran-ocoumarin: bromo-hy-droxy-seselin.

The title compound, C14H13BrO3 [systematic name: rac-(9S,10R)-9-bromo-10-hy-droxy-8,8-dimethyl-9,10-di-hydro-2H,8H-pyrano[2,3-f]chromen-2-one], is a substituted pyran-ocoumarin, obtained by bromination of seselin [8,8-dimethyl-2H,8H-pyrano[2,3-f]chromen-2-one], which was isolated from the Indian herb Trachyspermum stictocarpum (Aajmod). The pyrano ring has a distorted half-chair conformation and its mean plane is inclined to the coumarin mean plane by 1.6 (2)°. In the crystal, mol-ecules are linked by pairs of O-H⋯O hydrogen bonds, forming inversion dimers with an R22(16) ring motif. The dimers stack along the a-axis direction and are linked by offset π-π inter-actions, forming columns [inter-centroid distance = 3.514 (4) Å].

Crystal structure of bergapten: a photomutagenic and photobiologically active furan-ocoumarin.

The title compound, C12H8O4, is a furan-ocoumarin [systematic name: 4-meth-oxy-7H-furo[3,2-g]chromen-7-one], which was isolated from the Indian herb T. stictocarpum. The mol-ecule is almost planar with an r.m.s. deviation of 0.024 Šfor the hetero atoms of the fused-ring system. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming a three-dimensional framework. There are offset π-π inter-actions present involving the coumarin moieties stacking along the a-axis direction [shortest inter-centroid distance = 3.717 (3) Å].

Crystal structure of a bioactive sesquiterpene isolated from Artemisia reticulata.

The title compound, C15H24O2 {systematic name: 1-[6-hy-droxy-7-(propan-2-yl)-4-methyl-idene-2,3,3a,4,5,6,7,7a-octa-hydro-1H-inden-1-yl]ethanone} was iso-la-ted from A. reticulata by column chromatography over silica gel by gradient solvent elution. The mol-ecule comprises a bi-cyclo-[4.3.0]nonane ring bearing acet-oxy, hy-droxy and isopropyl substituents, and an exocyclic double bond on the cyclo-hexane ring. In the bicyclic skeleton, the cyclo-hexane ring adopts a chair conformation ring and the cyclo-pentane ring is in an envelope conformation. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds, forming chains along [010]. These chains are cross-linked by C-H⋯O hydrogen bonds.

Crystal structure of a photobiologically active furan-ocoumarin from Artemisia reticulata.

The title furan-ocoumarin, C14H12O4 [systematic name: 9-hy-droxy-2-(prop-1-en-2-yl)-2,3-di-hydro-7H-furo[3,2-g]chromen-7-one], crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. The two mol-ecules differ essentially in the orientation of the propenyl group with respect to the mean plane of the furan-ocoumarin moiety; the O-C(H)-C=C torsion angle is 122.2 (7)° in mol-ecule A and -10.8 (11)° in mol-ecule B. In the crystal, the A and B mol-ecules are linked via O-H⋯O hydrogen bonds, forming zigzag -A-B-A-B- chains propagating along [001]. The chains are reinforced by bifurcated C-H⋯(O,O) hydrogen bonds, forming ribbons which are linked via C-H⋯π and π-π inter-actions [inter-centroid distance = 3.602 (2) Å], forming a three-dimensional structure.

Healing property of the Piper betel phenol, allylpyrocatechol against indomethacin-induced stomach ulceration and mechanism of action.

AIM: To evaluate the protective activity of allylpyrocatechol (APC), the major antioxidant constituent of Piper betel, against the indomethacin-induced stomach ulceration in the rat model and correlates with its antioxidative and mucin protecting properties. METHODS: Male Sprague-Dawley rats were divided into five groups. Normal control rats (group I) were given the vehicle oral dose of gum acacia in distilled water (1 mL per rat); ulcerated control and treated rats (groups II-V) were given a single dose of indomethacin (30 mg/kg body wt.); group II rats were sacrificed 4 h after indomethacin administration; groups III-V rats were given the vehicle (1 mL per rat) or APC (2 mg/kg body wt.) or misoprostol (1.43 mug/kg body wt.) once daily by oral intubation for 7 d starting from 4 h after the indomethacin administration. After 7 d, the stomach tissues were excised for histological examination and biochemical analysis. RESULTS: Treatment with APC (2 mg/kg body wt per day) and misoprostol (1.43 mug/kg body wt per day) for 7 d could effectively heal the stomach ulceration as revealed from the ulcer index and histopathological studies. Compared to the zero day ulcerated group, treatment with APC and misoprostol reduced the ulcer index by 93.4% and 85.4% respectively (P < 0.05). Both APC and misoprostol accelerated ulcer healing observed in natural recovery (P < 0.05), their respective healing capacities not being significantly different. The healing capacities of APC and misoprostol could be attributed to their antioxidant activity as well as the ability to enhance the mucin content of the gastric tissues. Compared to the ulcerated untreated rats, those treated with APC and misoprostol showed near normal MDA levels, while the protein levels were 86% and 78% of the normal value respectively (P < 0.05). Likewise, both APC and misoprostol increased the SOD, catalase, and mucin levels significantly (P < 0.05), the effect of APC being better. CONCLUSION: APC can protect indomethacin-induced gastric ulceration due to its antioxidative and mucin protecting properties.