Farzana Kousar

A new antibacterial compound produced by an indigenous marine bacteria — fermentation, isolation, and biological activity

The use of microorganisms for biological purpose has become an effective alternative to control pathogens. A marine bacterium Pseudomonas aeruginosa was isolated from Eal fish of Baluchistan coast of Pakistan. This strain produced a bactericidal antibiotic against environmental and clinical isolates. In this study, we purified bactericidal antibiotic from the ethyl acetate extract of the cells of P. aeruginosa and analyzed its chemical structure. Based on spectrometric analysis, this compound 1 is proposed to be 1-methyl-1,4 dihydroquinoline and is active against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-sensitive S. aureus (MSSA), Salmonella typhi, Shigella flexneri, Escherichia coli, Proteus mirabilis, Vibrio aliginolyticus, Micrococcus luteus, Enterococcus faecalis, Enterobacter faecium but it is not active against G streptococci, Candida albicans, Aspergillus niger. Minimal inhibitory concentration for Gram-positive bacteria was between 50 and 75 µg mL−1 and for Gram-negative bacteria 75–100 µg mL−1.

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.

Two new trans-clerodane diterpenoids from Otostegia limbata

Two new tricyclic clerodane-type diterpenoids, limbatolide D (1) and limbatolide E (2), have been isolated from the roots of Otostegia limbata. Their structures and the relative configuration were established on the basis of spectral methods, especially two-dimensional (2D) NMR techniques.

Isolation of a new lipoxygenase active saponin and a new triterpenoid from the leaves of trachelospermum lucidum

A new saponin trivially named leucioside (1) and a new triterpenoid along with two known lignans trachelosiaside (3) and matairesionol (4) C-glycosides, were isolated from the butanolic fraction of Trachelospermum lucidum. Compounds 1 and 4 showed potent inhibitory activity against lipoxygenase while compounds 2 and 3 showed moderate activity against lipoxygenase.