Esahak Ali

A Novel Antioxidant and Antiapoptotic Role of Omeprazole to Block Gastric Ulcer through Scavenging of Hydroxyl Radical

The mechanism of the antiulcer effect of omeprazole was studied placing emphasis on its role to block oxidative damage and apoptosis during ulceration. Dose-response studies on gastroprotection in stress and indomethacin-induced ulcer and inhibition of pylorus ligation-induced acid secretion indicate that omeprazole significantly blocks gastric lesions at lower dose (2.5 mg/kg) without inhibiting acid secretion, suggesting an independent mechanism for its antiulcer effect. Time course studies on gastroprotection and acid reduction also indicate that omeprazole almost completely blocks lesions at 1 h when acid inhibition is partial. The severity of lesions correlates well with the increased level of endogenous hydroxyl radical (⋅OH), which when scavenged by dimethyl sulfoxide causes around 90% reduction of the lesions, indicating that ⋅OH plays a major role in gastric damage. Omeprazole blocks stress-induced increased generation of ⋅OH and associated lipid peroxidation and protein oxidation, indicating that its antioxidant role plays a major part in preventing oxidative damage. Omeprazole also prevents stress-induced DNA fragmentation, suggesting its antiapoptotic role to block cell death during ulceration. The oxidative damage of DNA by ⋅OH generated in vitro is also protected by omeprazole or its analogue, lansoprazole. Lansoprazole when incubated in a ⋅OH-generating system scavenges⋅OH to produce four oxidation products of which the major one in mass spectroscopy shows a molecular ion peak atm/z 385, which is 16 mass units higher than that of lansoprazole (m/z 369). The product shows no additional aromatic proton signal for aromatic hydroxylation in 1H NMR. The product absorbing at 278 nm shows no alkaline shift for phenols, thereby excluding the formation of hydroxylansoprazole. The product is assigned to lansoprazole sulfone formed by the addition of one oxygen atom at the sulfur center following attack by the ⋅OH. Thus, omeprazole plays a significant role in gastroprotection by acting as a potent antioxidant and antiapoptotic molecule.

Homogeneous enzyme immunoassay of estradiol using estradiol-3-0-carboxymethyl ether as hapten

A homogeneous enzyme immunoassay for estradiol estimation has been developed, which can be extended to other steroids. A new procedure for the preparation of estradiol -3-0- carboxymethyl ether by a simple one step reaction in high yield (90%) has been described. This hapten has been used for raising highly specific anti-estradiol antibody in rabbits and for preparation of enzyme conjugates. Two different enzymes, lysozyme and glucose -6- phosphate dehydrogenase have been studied for their suitability as enzyme labels. Our results indicate that lysozyme-conjugate meets the essential requirement for a practical enzyme immunoassay. The advantage of the present nonradioactive procedure is the overall simplicity, low cost and high stability of the reagents.

Structure of phaseolinone, a novel phytotoxin from macrophomina phaseolina

Abstract Structure of phaseolinone, a phytotoxin isolated from the fungus Macrophima phaseolina (Tassi) Gold, has been established as 1 .

Antibody to folic acid: increased specificity and sensitivity in ELISA by using ε-aminocaproic acid modified BSA as the carrier protein

For raising high titre and specific antibody to haptens or drugs, epsilon-aminocaproic acid modified bovine serum albumin (epsilon-ACA-BSA) was prepared for use as a carrier protein. Folic acid (FA) was coupled to epsilon-ACA-BSA, Imj.BSA and BSA for raising antibodies in rabbits. Enhancement of FA immunogenicity with FA-ACA-BSA was observed. Apart from determination of titre by indirect ELISA, dose-response behaviour and specificity of these antisera were also compared. FA-ACA-BSA antibody showed high sensitivity and specificity. Using this antibody, an ELISA method for the determination of FA was developed. The study provides a simple approach to raise highly specific and high titre antibody against small molecules.

Studies on Indian medicinal plants—XXVIII : Sesquiterpene lactones of Enhydra fluctuans Lour. Structures of enhydrin, fluctuanin and fluctuadin

Abstract The structures of enhydrin (2) and the co-occurring sesquiterpene lactones, viz. fluctuanin (3) and fluctuadin (4) isolated from Enhydra fluctuans Lour have been established. The stereochemistry of enhydrin has been suggested from NMR data. Selective hydrolysis of the acetate and the glycidate group in 2 yielded the alcohols 11 and 16 indicating acyl migration during their formation. Acetylation of 11 led further to acetolysis of the glycidate ester function to afford the diacetate 17. The location of the two acyl groups in 2 (and also in 3 and 4) still remain to be settled.

Isolation and structure of wallichoside, a novel pteroside from Pteris wallichiana

Abstract Wallichoside has been isolated from the rhizomes of Pteris wallichiana and its structure and absolute configuration has been established as the 3-β- d -glucoside of 2 S , 3 S -pterosin C on the basis of UV, IR, NMR and MS data of wallichoside and its derivatives.

Direct microtitre plate enzyme immunoassay of testosterone in unextracted serum

A method for enzyme immunoassay of testosterone in serum has been developed which does not require extraction of the serum with organic solvents. The release of testosterone from the binding proteins is achieved by heating the serum at 70 degrees C for 30 min in an alkaline buffer. The results correlated well (r = 0.96) with those of a radioimmunoassay using 125I-labelled testosterone and with enzyme immunoassay with prior extraction of samples (r = 0.98). The detection limit of the assay is 1 pg per well and the turn around time for 36 samples is 3.5 h. The procedure is simple and well suited for routine analysis.

Bharatamine - a unique protoberberine alkaloid from alungium lamarckii thw., biogenetically derived from monoterpenoid precursor

Abstract Bharatamine (I), mp 182–183°, a novel racemic protoberberine alkaloid unoxygenated at ring D and biogenetically derivable from loganin, a pathway hitherto unknown for this class of compounds, has been isolated from the seeds of Alanguim lamarckii and structure established by an unequivocal synthesis.

High resolution affinity chromatography of an anti-steroid antiserum by gradient elution with propionic acid.

Chromatographic resolution of polyclonal antibodies is a challenging analytical problem and a successful method may have many applications. We have resolved polyclonal antibodies against testosterone 3-(O-carboxymethyl)oxime on a homologous testosterone-Sepharose matrix by using a ternary gradient system of propionate-1 M propionic acid-2 M propionic acid. Nineteen peaks were detected, sixteen of which were characterized by steroid binding activity and IgG assay. The relative affinities of the pooled fractions, determined by ELISA and by thiocyanate elution, correlated well with their retention times. The slopes of the displacement curves in antigen-immobilized testosterone ELISA increased with retention times of the fractions; testosterone required for 50% displacement being, 90, 5.8 and 24 ng/well for fraction I, fraction XVI and total antiserum, respectively. Cross-reactivity of the fractions towards 5alpha-dihydrotestosterone varied from 31 to 74% compared to 47% in the total antiserum.

Studies on indian medicinal plants : part 91 1 -structure and synthesis of alamaridine, a novel 5-methylbenzopyrioquinolizine alkaloid from alangium lamarckii

Abstract The structure of alamaridine (1) a novel benzopyridoquinolizine alkaloid, was established by spectral data. However, its stereochemistry could only be determined now by a total synthesis involving the key cyclisation of an 1-methyl-2-pyridylmethyl-3,4-dihydroisoquinolinium salt 19a in presence of pivaloyl chloride and triethylamine. O-Benzyldehydroalamaridine thus formed was reduced by sodium cyanoborohydride and then deprotected to obtain alamaridine (1) and 5-epi-alamaridine (26). Isoalamaridine (27) and its 5-epimer (28) were also synthesised following the same route.