Muhammad Athar Abbasi

Phenolic glycosides from Symplocos racemosa: natural inhibitors of phosphodiesterase I.

One new phenolic glycoside named benzoylsalireposide (1) along with one known phenolic glycoside named salireposide (2) have been isolated from Symplocos racemosa. Four other known compounds i.e. beta-amyrin (3), oleonolic acid (4), beta-sitosterol (5) and beta-sitosterol glycoside (6) were also isolated from this plant. The structure elucidation of the isolated compounds was based primarily on 1D- and 2D-NMR analysis, including COSY, HMQC, and HMBC correlations. The compound 1 and 2 showed inhibitory activity against snake venom phosphodiesterase I.

New salirepin derivatives from Symplocos racemosa

The phytochemical investigation of the n-butanol soluble fraction of the bark of stem of Symplocos racemosa Roxb. yielded two new phenolic glycosides of salirepin series, symplocuronic acid (1) and sympocemoside (2), while salirepin (3) was isolated for the first time from this plant. The structures of the new compounds were identified by 1D and 2D NMR techniques along with other spectral evidences and by comparison with the published data of closely related compounds.

A New Bacillus pasteurii Urease Inhibitor from Euphorbia decipiens

Inhibition of Bacillus pasteurii urease enzyme by 3,7,15-tri-O-acetyl-5-O-nicotinoyl-13,14-dihydroxymyrsinol (1), a diterpene ester with a myrsinol-type skeleton, isolated from Euphorbia decipiens Boiss. & Buhse, was un-competitive consistent with the molecular docking results. The Ki value was 117.40 ± 0.7 μM.

Kinetics studies on triacontanyl palmitate: a urease inhibitor

The mechanism of inhibition of jack bean and Bacillus pasteurii ureases was investigated by triacontanyl palmitate (1) which is a long-chain fatty ester and has been isolated from Symplocos racemosa Roxb. Lineweaver–Burk, Dixon plots, and their secondary replots showed that 1 is a non-competitive inhibitor of these enzymes. Ki values were found to be 60.03u2009±u20091.72 and 88.23u2009±u20090.31u2009µM against jack bean and B. pasteurii ureases, respectively. †Dedicated to the memory of Dr Mohammad Hussain Panjwani (1940–1992), a renowned philanthropist and scholar.

Lipoxygenase inhibiting ethyl substituted glycoside from Symplocos racemosa.

Phytochemical investigation of Symplocos racemosa resulted in the isolation of a new ethyl substituted glycoside, 1-ethyl brachiose-3′-acetate (1) along with four known compounds ketochaulmoogric acid (2), nonaeicosanol (3), triacontyl palmitate (4) and methyl triacontanoate (5). The substitution of ethyl group on 1 was natural because during the course of extraction and purification ethanol was not used. The structural elucidation of the isolated compounds was based primarily on 1D- and 2D-NMR analysis, including COSY, HMQC, and HMBC correlations. The glycoside 1 and triacontyl palmitate (4) displayed the inhibitory potential against lipoxygenase and urease enzyme, respectively.

Phenolic Glycosides from Symplocos racemosa

The re-investigation of the chemical constituents of the bark of the stem of Symplocos racemosa Roxb. led to the isolation of two new phenolic glycosides, Symconoside A (1) and Symconoside B (2). The structures of the new compounds were determined by 1D and 2D-homonuclear and heteronuclear NMR spectroscopy, chemical evidences, and by comparison with the published data of the closely related compounds. The phenolic glycosides 1 and 2 displayed in vitro inhibitory activity against phosphodiesterase-I with the IC50 values of 158±0.02 and 900±0.08 μM, respectively.

New ceramides from Platytaenia multicaule.

Phytochemical investigation of Platytaenia multicaule resulted in the isolation of two new ceramides, N-triacontylpentadecanamide (1) and 1,3,4-trihydroxy-2,dodecanoylamino-(24E)-unacotenene (2), along with two known compounds, β-sitosterol (3) and β-sitosterol glycoside (4). The structure elucidation of the isolated compounds was based primarily on 1D and 2D NMR analyses, including COSY, NOESY, HMQC, and HMBC correlations.

Three new sesquiterpene hemiacetals from Achillea vermicularis

Three new sesquiterpene hemiacetals, tentatively named as achilleanone (1), vermiculone (2) and vermicularone (3) have been isolated from Achillea vermicularis, along with three other known compounds β-amyrin, oleonolic acid and β-sitosterol. The structure elucidation of new compounds was based primarily on two-dimensional (2D) NMR techniques including Nuclear Overhauser Effect/Enhancement (NOE), heteronuclear multiple quantum coherence (HMQC), heteronuclear multiple bond correlation (HMBC) and nuclear overhauser effect spectroscopy (NOESY) experiments. Compounds 1, 2 and 3 have displayed inhibitory potential against lipoxygenase enzyme in a concentration-dependent fashion with promising IC50 values.

A New α-Glucosidase Inhibiting Dithiadiazetidin Derivative from Symplocos racemosa

The phytochemical investigation of the n-butanol soluble fraction of Symplocos racemosa Roxb. resulted in the isolation of a new dithiadiazetidin derivative; symploate (1). Its structure was established through various 1Dand 2D NMR techniques together with high-resolution mass spectrometric techniques and spectral evidences. The symploate (1) showed moderate inhibitory activity against α-glucosidase in a concentration-dependent fashion with an IC 5 0 value of 691.1 ′ 3.29 μM.

Synthesis and Molecular Docking Study of Some New 4-{[4-(2-Furoyl)-1-piperazinyl]methyl}-N-(substituted-phenyl)benzamides as PossibleTherapeutic Entrants for Alzheimers Disease

In the present work, a new series of different 4-{[4-(2-furoyl)-1-piperazinyl]methyl}-N-(substituted-phenyl) benzamides (5a-h) have been synthesized as possible therapeutic agents for the treatment of Alzheimer’s disease. The structural confirmation of all the synthesized compounds was carried out by their IR, 1H-NMR and EI-MS spectral data. Enzyme inhibition activity was performed against butyrylcholinestrase enzyme, which revealed that, 4-{[4-(2-furoyl)-1- piperazinyl]methyl}-N-(4-ethylphenyl)benzamide (5b) showed excellent IC50 value 0.82 ± 0.001 μM relative to Eserine, a reference standard having IC50 value of 0.85 ± 0.0001 μM. The enhanced potential of this molecule may be attributed to the 4-ethylphenyl group. As the cholinesterase enzyme inhibitors are good targets for Alzheimer’s disease, therefore, the inhibition study of these synthesized molecules was carried out to discover their possible therapeutic effect as target for aforesaid disease.