Mashooda Hasan

A quinone methide diterpenoid from the root of Salvia moorciuftiana

Abstract A new diterpenic methylenquinone, 1 5-deoxyfuerstione, was isolated from the root of Salvia moorcraftiana. The structure of this natural compound was established by chemical and spectroscopic means to be 11 -hydroxy- 5,7, 9(11),13-abietatetraen-12-one. The previously known diterpenoids 7α-acetoxyroyleanone and taxodione were also found in the same source.

Epoxysalviacoccina, neo-clerodane diterpenoid from Salvia plebeia

Abstract A new neo-clerodane derivative, epoxysalviacoccin, has been isolated from the aerial part of Salvia plebeia , together with the previously known diterpenoid salviacoccin. The structure of epoxysalviacoccin, 2β,3β; 15,16-diepoxy-10β-hydroxy-neo-cleroda-7,13(16),14-triene-17,12 R ; 18,19-diolide, has been established by spectroscopic means and by partial synthesis from salviacoccin.

Two new compounds from the aerial parts of Bergenia himalaica Boriss and their anti-hyperglycemic effect in streptozotocin-nicotinamide induced diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE Bergenia himalaica Boriss is mainly distributed in the temperate Himalayas between altitudes of 900 and 3000m ranging from the southeastern regions in central Asia and northern regions in South Asia. The plant has a long history of its use in traditional medicine for the treatment of various diseases such as diabetes, urinary complaints, kidney stones, hemorrhagic diseases and epilepsy. The aim of this study is to isolate pure compounds from Bergenia himalaica Boriss, elucidate their structures and determine their blood glucose lowering activity to obtain additional scientific evidence for its usage in traditional medicine for the management of diabetes. MATERIALS AND METHODS The crude methanolic extract from the aerial parts of Bergenia himalaica Boriss was separated into EtOAc and water sub-extracts and the EtOAc sub-extract was further divided into petroleum ether soluble and insoluble fractions. The pet-ether insoluble fraction was subjected to fractionation through column chromatography followed by prep. TLC. The blood glucose lowering activity of the 2 new compounds was evaluated in streptozotocin-nicotinamide induced diabetic rats. Additionally, glucose-stimulated insulin secretion was measured on isolated mice islets. RESULTS Two new compounds bergenicin and bergelin were isolated and their structures determined on the basis of spectral analysis. Significant decrease of blood glucose was observed at 1-h (1.0mg/kg) and 2-h (0.5mg/kg), after bergenicin administration to the diabetic rats and at 2-h (1.0mg/kg) and 3-h (0.5mg/kg), after bergelin administration. Bergenicin, but not bergelin, enhanced glucose-stimulated insulin secretion in isolated pancreatic islets. CONCLUSIONS In the present studies two new compounds, bergenicin and bergelin were isolated from Bergenia himalaica Boriss and their structures were elucidated. Both the compounds showed anti-hyperglycemic effects in streptozotocin-nicotinamide induced diabetic rats. Bergenicin showed insulinotropic effect; suggesting that the anti-hyperglycemic effect is mostly due to enhancement of insulin secretion from pancreatic β-cells.

Leucasin, a triterpene saponin from Leucas nutans

A new saponin, leucasin, has been isolated from Leucas nutans and characterized on the basis of chemical investigation and spectroscopic studies as 3-O-[beta-D-glucopyranosyl(1----2)beta-D-glucopyranosyl]2 alpha, 3 beta-dihydroxylup-20(29)-ene. Lupeol palmitate, sitosterol and stigmasterol were also isolated.

ABSOLUTE CONFIGURATION OF CHIRAL 1,3,4,5-TETRAHYDRO-2H-1,5-BENZODIAZEPIN-2-ONES

X-ray studies are carried out to correlate the Cotton effects in CD spectra with the absolute configuration of a series of previously reported chiral 1,3,4,5-tetrahydro-2H-1 ,5-benzodazepin-2-ones.

SYNTHESES OF ANOMERIC PAIRS OF NEW C-NUCLEOSIDES VIA 1,3-DIPOLAR CYCLOADDITION REACTION, PART II

Abstract 1,3-Dipolar cycloaddition of dipolarophiles (1) and (2) with endocyclic heterocyclic azomethine ylides (4), (14) and (24), prepared in situ, leads to the protected β-and α-C-nucleo-sides (7), (8), (17), (18), (27) and (28), respectively. These, on subsequent hydrolysis, provide the corresponding C-nucleosides. The structures of all the synthesized com pounds are con firmed through analytical and spectral data. The assignment of configuration at C -1′ position of the C-nucleosides could be done by a comparative study of the properties of the corresponding α and β anomers with a reasonable degree of certainity.

Circular Dichroism Studies on Chiral 1,3,4,5-Tetrahydro-2H-1,5- benzodiazepin-2-ones

From forty one chiral benzodiazepin-2-ones the UV and CD data are reported and the bands discussed with respect to corresponding electronic transitions respectively stereochemical features.

cis-(9S,10S)-Methyl 1-propyl-1,2,3,4-tetra-hydro-β-carboline-3-carboxyl-ate.

The title compound, C16H20N2O2, was synthesized from (S)-tryptophan methyl ester hydrochloride and butyraldehyde. The absolute configuration 9S,10S was assigned on the basis of the unchanging chirality of the C9 centre. The NH group of the indole ring is involved in intermolecular N—H⋯O hydrogen bonding, while the NH group of the six-membered ring is not. This latter ring has a half-chair conformation.

Circular Dichroism Studies on New Optically Active 1,5-Benzodiazepine Derivatives

Abstract From thirty three new optically active 1,5-benzodiazepine derivatives the UV and CD data are reported and the bands discussed related to corresponding electronic transitions respectively stereochemical features.

Factors Influencing the Acid Lability of Substituted Arylsulphonyl Arginine Protecting Groups

Abstract The kinetics of hydrolysis of new, NG-protected 2,4,6-triisopropylbenzene-sulphonyl (6). 4-methoxy-3,5-di-tert-butylbenzenesulphonyl (12) and phenanthrene-3-sulphonyl (17) Fmoc derivatives of L-arginine (1) in comparison with commercially available Fmoc-Arg(Mtr)-OH (Mtr = 4-methoxy-2,3,6-trimethyl-benzenesulphonyl (2)) are studies. The acid lability of the arylsulphonyl group is decreasing as follows Mtr > Tip > Mtbs > Phen. The effect of electron- donating alkyl groups as substituents in increasing the acid lability of the arylsulphonyl residue seems to be in the order of methyl > isopropyl > tert-butyl while the effect of extended derealization does not appreciably increase the acid lability.