A compilation of the constituents isolated from Swertia species covering the literature up to December 2003 is presented. The botanical classification and ethno-pharmacology of Swertia plants, as well as the biological activities and pharmacological applications of both distinct phytochemicals and medicinally active plant materials (formulations, extracts, etc.) are discussed in detail.

The antimicrobial potential of two bioflavonoids, i.e., 5,7-dihydroxy-4',6,8-trimethoxyflavone (1) and 5,6-dihydroxy-4',7,8-trimethoxyflavone (2), isolated from Limnophila heterophylla Benth. and L. indica (Linn.) Druce (Scrophulariaceae), respectively, were evaluated against the microbial strains Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Alternaria solani, and Candida albicans. Compounds 1 and 2 exhibited moderate but broad antimicrobial activities against both Gram-positive and Gram-negative bacteria and also against the fungal pathogens. Moreover, the mechanism of action of 1 and 2 on the cellular functions or structures of some of the microorganisms was studied. Compound 1 showed a bactericidal effect against E. coli and S. aureus (MICs of 200 and 250 μg/ml, resp.), while compound 2 was found to effectively kill B. subtilis by cell lysis. The growth of A. solani and C. albicans was inhibited by compounds 1 and 2, respectively. The effects of the flavonoids on the cellular structures and the carbohydrate metabolic pathways were studied by scanning electron microscopy (SEM) of the treated cells and by assessing the specific activity of key enzymes of the pathways, respectively. At sublethal doses, they enhanced the activity of gluconeogenic fructose bisphosphatase, but decreased the activity of phosphofructokinase and isocitrate dehydrogenase, the key enzymes of the EmbdenMeyerhofParnas pathway and the tricarboxylic acid cycle, respectively.

Other natural products U 0800 Chemical Constituents of Limnophila indica. -Two new flavanoids (I) are isolated together with two known structurally related compounds and a known β-sitosterol from the aerial parts and roots of the above mentioned aquatic herb. Their structures are elucidated on the basis of spectral and chemical studies. -(BRAHMACHARI*, G.; JASH, S. K.; GANGOPADHYAY, A.; SARKAR, S.; LASKAR, S.; GORAI, D.; Indian J.

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X-ray diffraction studies were carried out on single crystals of two flavonoids, viz. 5-hydroxy-6,7,4′-trimethoxyflavone, C 18 H 16 O 6 , (I) and 5-hydroxy-3,7,4′-trimethoxyflavone, C 18 H 16 O 6 , (II). Crystal structures of both the flavonoids were solved by direct methods and refined by full-matrix least-squares procedures. In both the molecules, the benzopyran moiety is planar. The dihedral angle between the phenyl ring and the benzopyran portion is 5⋅50(4)° in (I) and 29⋅11(5)° in (II). In (I), the crystal packing is influenced by O-H…O hydrogen bonds, and weak C-H…O and π…π interactions whereas in (II) the crystal structure is stabilized by the presence of four intermolecular short contacts of the type C-H…O. There is also one C-H…π hydrogen bond with H… centroid distance of < 2⋅7 Å. The molecules are further stabilized by π-π interactions.