Syed Shafi

Synthesis of novel 1,2,3-triazole based benzoxazolinones: their TNF-α based molecular docking with in-vivo anti-inflammatory, antinociceptive activities and ulcerogenic risk evaluation.

A library of novel bis-heterocycles containing benzoxazolinone based 1,2,3-triazoles has been synthesized using click chemistry approach. The compound 3f exhibited potent selective COX-2 inhibition of 59.48% in comparison to standard drug celecoxib (66.36% inhibition). The compound 3i showed significant (p < 0.001, 50.95%), TNF-α inhibitory activity as compared to indomethacin (p < 0.001, 64.01%). The results of the carrageenan induced hind paw oedema showed that compounds 3a, 3f, 3i, 3o, and 3e exhibited potent anti-inflammatory activity in comparison to Indomethacin. The molecular docking studies revealed that 3i exhibits strong inhibitory effect due to the extra stability of the complex because of an extra π-π bond. The histopathology report showed that none of the compounds caused gastric ulceration.

Design, synthesis, in silico molecular docking and biological evaluation of novel oxadiazole based thiazolidine-2,4-diones bis-heterocycles as PPAR-γ agonists.

A library of novel 1,3,4-oxadiazole and 2-4-thiazolidinedione based bis-heterocycles 7 (a-r) has been synthesized which exhibited significant PPAR-γ transactivation and blood glucose lowering effect comparable with the standard drugs Pioglitazone and Rosiglitazone. Compounds 7m and 7r did not cause body weight gain and were found to be free from hepatotoxic and cardiotoxic side effects. Compounds 7m and 7r increased PPAR-γ gene expression by 2.10 and 2.00 folds, respectively in comparison to the standard drugs Pioglitazone (1.5 fold) and Rosiglitazone (1.0 fold). Therefore the compounds 7m and 7r may be considered as potential candidates for development of new antidiabetic agents.

Novel benzenesulfonylureas containing thiophenylpyrazoline moiety as potential antidiabetic and anticancer agents

In the present study a library of twenty six benzenesulfonylureas containing thiophenylpyrazoline moiety has been synthesized. All the compounds were docked against PPAR-γ target. Most of the compounds displayed higher dock score than standard drugs, glibenclamide and rosiglitazone. All the synthesized compounds were primarily evaluated for their antidiabetic effect by oral glucose tolerance test. Further assessment of antidiabetic potential of sixteen active compounds was then done on STZ induced diabetic model. The results of in vivo activity by both the methods were found to be consistent with each other as well as with docking studies. Change in body weight of STZ induced animals post treatment was also assessed at the end of study. In vitro PPAR-γ transactivation assay was performed on active compounds in order to validate docking results and the most active compound 3 k was also shown to elevate gene expression of PPAR-γ. Furthermore, the compounds were screened by National Cancer Institute, Bethesda for anticancer effect and two compounds 3h and 3 i were selected at one dose level since they exhibited sensitivity towards tumor cell lines (mainly melanoma).

Design and Synthesis of Butenolide‐based Novel Benzyl Pyrrolones: Their TNF‐α based Molecular Docking with In vivo and In vitro Anti‐inflammatory Activity

A focused library of novel benzyl pyrrolones has been synthesized and their in silico molecular docking studies carried out against TNF‐α target. Among all the docked molecules, compound 3f showed best glide score of −6.89. All the synthesized compounds were evaluated for in vivo anti‐inflammatory activity by carrageenan‐induced paw edema model. Compounds showing significant anti‐inflammatory activity were further tested for their in vitro TNF α expression. Compounds 3b and 2b were found to show significant inhibition of 76.22% and 71.47%, respectively after 5 h in comparison with standard drug indomethacin, which showed 80.98% inhibition of inflammation. Compounds 3b and 2b also suppressed TNF α level by 65.03% and 60.90% as compared indomethacin, which showed 68.84% of inhibition. Compound 3b showed significant analgesic activity of 60.04%, and its activity was comparable with indomethacin (64.04%). Compounds 3b and 2b were also tested for their effect on protein expression of COX‐2 and NF‐κB in the liver tissues. Compounds 3b and 2b were further evaluated for their gastric risk and lipid peroxidation action and showed superior GI safety along with reduction of LPO as compared to indomethacin. Hepatotoxicity study showed that these two compounds did not cause any damage to liver.

Study of the adjuvanticity of lysine lipopeptides; carbamate analogs elicit strong Th1 and Th2 response to ovalbumin in mice

Bacterial lipoproteins and their synthetic analogs are strong immune modulators of the early host responses. In view of the strong adjuvanticity of bacterial lipopeptide mimics bearing lysine residues, a focused library of lipidated dipeptides and tripeptides has been synthesized with a view to understand the pattern of activity vis a vis the site and extent of lipidation. Compounds 4, 5 and 14 stimulate OVA specific IgG titer, neutralization of antibodies (IgG1 and IgG2a), T lymphocyte sub-sets (CD4/CD8) and its production of soluble mediators for Th1 (IFN-γ)/Th2 (IL-4) cytokines and costimulatory molecules (CD80/CD86) which are ideal traits of immune adjuvants. The results support lipidated lysine dipeptides as potent enhancers of humoral and cell mediated immune responses and thus might become promising immune-adjuvants for self adjuvanted vaccines.

Synthesis and tyrosinase inhibition activity of trans-stilbene derivatives

Synthesis of a focussed library of trans-stilbene compounds through Wittig and other base catalysed condensation reactions is presented. The synthesized stilbenes were screened for their inhibitory potential against murine tyrosinase activity to explore the structure activity relationship (SAR). Presence of electron withdrawing group (-CN) at the double bond and hydroxyl group or halogen atom especially at para-position on the aromatic rings was found to significantly elevate the inhibitory activity. Among all the compounds screened, compounds 2, 6, 8, 10, 11, 15 and 21 were found to exhibit appreciable inhibitory activity. Compound 21 ((E)-2,3-bis(4-Hydroxyphenyl)acryonitrile) was found to be the most active with an IC50 value of 5.06 μM which is less than half of the value 10.78 μM observed for resveratrol (common standard used in murine tyrosinase activity studies) under similar conditions. The results obtained from the present study reveal structural/functional group sensitivity for the tyrosinase inhibitory activity of stilbenoid moieties and are expected to be very helpful for the design and synthesis of novel, selective and effective tyrosinase inhibitors.

β-Nitrostyrenes as Potential Anti-leishmanial Agents.

Development of new therapeutic approach to treat leishmaniasis has become a priority. In the present study, the antileishmanial effect of β-nitrostyrenes was investigated against in vitro promastigotes and amastigotes. A series of β-nitrostyrenes have been synthesized by using Henry reaction and were evaluated for their antimicrobial activities by broth microdilution assay and in vitro antileishmanial activities against Leishmania donovani promastigotes by following standard guidelines. The most active compounds were futher evaluated for their in vitro antileishmanial activities against intracellular amastigotes. Among the tested β-nitrostyrenes, compounds 7, 8, 9, 12, and 17 exhibited potential activities (MICs range, 0.25–8 μg/mL) against clinically significant human pathogenic fungi. However, the microbactericidal concentrations (MBCs) and the microfungicidal concentrations (MFCs) were found to be either similar or only two-fold greater than the MICs. Anti-leishmanial results demonstrated that compounds 9, 12, 14, and 18 were found to be most active among the tested samples and exhibited 50% inhibitory concentration (IC50) by 23.40 ± 0.71, 37.83 ± 3.74, 40.50 ± 1.47, 55.66 ± 2.84 nM against L. donovani promastigotes and 30.5 ± 3.42, 21.46 ± 0.96, 26.43 ± 2.71, and 61.63 ± 8.02 nM respectively against intracellular L. donovani promastigotes amastigotes respectively which are comparable with standard AmB (19.60 ± 1.71 nM against promastigotes and 27.83 ± 3.26 nM against amastigotes). Compounds 9, 12, 14, and 18 were found to have potent in vitro leishmanicidal activity against L. donovani and found to be non-toxic against mammalian macrophages even at a concentration of 25 μM. Nitric oxide (NO) estimation studies reveals that these compounds are moderately inducing NO levels.

Design and Synthesis of Novel 1,2,3-Triazole- and 2-Isoxazoline-Based Bis-Heterocycles as Immune Potentiators

A series of novel bis‐heterocycles encompassing isoxazolines and triazoles were synthesized through a novel one‐pot procedure that involves in situ generation of nitrile oxide and its 1,3‐dipolar cycloaddition to variedly substituted acrylates. The synthesized bis‐heterocycles (8a–l) were subjected to in vitro lymphocyte proliferation assays followed by in vivo studies of the more active compounds (8g and 8h) to assess their influence on various aspects of the immune system like ex vivo splenocyte proliferation (T‐ and B‐cell proliferation), antibody production (HA titer), delayed‐type hypersensitivity reaction, T‐cell subtypes (CD4 and CD8), cytokine production (IL‐2, IFN‐γ, and IL‐4), NO (macrophage) production, and toxic effects. The results from the in vitro and in vivo studies establish that the tested compounds 8g and 8h possess excellent immunopotentiating activity.

Design, synthesis and biological evaluation of spiropyrimidinetriones oxazolidinone derivatives as antibacterial agents

Gram-positive bacteria are among the most common human pathogens associated with clinical infections which range from mild skin infections to sepsis. Resistance towards existing class of drugs by Gram-positive bacteria including methicillin resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis (MRSE) and vancomycin resistant enterococci (VRE) is a growing concern. There is an urgent need to discover new antibiotics which are active against resistant strains of Gram positive bacteria. We report herein a novel class of spiropyrimidinetrione oxazolidinone derivatives as novel antibacterial agents. Key step towards the synthesis of title compounds involved the use of tert-amino reaction with [1,5]-hydride shift leading to the new CC bond formation. Compound 30n has demonstrated potent antibacterial activity against a panel of Gram-positive microbial strains including MRSA, MRSE, and LNZ and vancomycin resistant strains of E. faecalis. Further, molecular docking studies suggest that 30n has binding mode similar to that of LNZ in 50S RNA ribosome.

Design and synthesis of pyridazinone-substituted benzenesulphonylurea derivatives as anti-hyperglycaemic agents and inhibitors of aldose reductase – an enzyme embroiled in diabetic complications

Abstract Thirty new aryl-pyridazinone-substituted benzenesulphonylurea derivatives (I–XXX) were synthesized and evaluated for their anti-hyperglycaemic activity in glucose-fed hyperglycaemic normal rats. Twenty-three compounds (III–XI, XIV–XVII, XIX–XXIV, XXVI and XXVIII–XXX) showed more or comparable area under the curve (AUC) reduction percentage (ranging from 21.9% to 35.5%) as compared to the standard drug gliclazide (22.0%). On the basis of docking results, 18 compounds were screened for their in vitro ability to inhibit rat lens aldose reductase. Ten compounds (III–VI, XII, XVI–XVIII, XXI and XXVII) showed ARI activity with IC50 ranging from 34 to 242 μM. Out of these, two compounds IV and V showed best ARI activity which is comparable with that of quercetin. As a result, two compounds (IV and V) possessing significant dual action (anti-hyperglycaemic and aldose reductase inhibition) were identified and may be used as lead compounds for developing new drugs.