Nusrat Masood

Synthesis of neolignans as microtubule stabilisers

Tubulin is a well established target for anticancer drug development. Lignans and neolignans were synthesized as tubulin interacting agents. Neolignans 10 and 19 exhibited significant anticancer activity against MCF-7 and MDAMB-231 human breast cancer cell lines. Both the compounds effectively induced stabilization of microtubule at 4 and 20 μM concentrations respectively. Neolignan 10 induced G2/M phase arrest in MCF-7 cells. Docking experiments raveled that 10 and 19 occupied the same binding pocket of paclitaxel with some difference in active site amino acids and good bioavailability of both the compounds. In in vivo acute oral toxicity 10 was well tolerated up to 300 mg/kg dose in Swiss-albino mice.

Activity guided isolation and characterization of antioxidant and antibacterial agents from some local Nigerian plants

This study aimed to present the activity guided fractionation, isolation and characterization of antioxidants and antibacterial agents from combined mixture of plants (Vitex doniana, Diospyros mesipiliformis, Acacia polycantha, Pirinari macrophylla, Ficus sycomorus and Parkia biglobosa) and that of Pergularia tomentosa. Combined Mixture of Plants (CMP) is used locally in ratio of 1:1 for the treatment of bacterial infections. The CMP and P. tomentosa were extracted with methanol separately; the residues obtained were also separately suspended in water and successively fractionated with hexane, ethylacetate and n-butanol. All the fractions obtained were screened for antimicrobial and antioxidant activities. For CMP, only the ethyl acetate fraction (EF) indicated marginal antibacterial activity with 8.0, 7.0 and 7.0 mm zone of inhibition against Micrococcus luteus (MTCC 2470), Bacillus subtilis (MTCC 121) and Salmonella typhimurium, respectively. Minimum inhibitory concentration (MIC) for the CMP was greater than 1000 for M. luteus and S. typhimurium and 87.5 μg/ml for B. subtilis. The CMP fraction was subjected to chromatographic separations which resulted in the isolation and characterization of five bioactive constituents, gallic acid, 3β-OH-α-amyrin, 5,7,3’.4’,5’pentahydroxy-3-O-glucophyranoside flavones (myricetin 3-O-β-rhamnopyranoside), 5,7,3’,4’ tetrahydroxy-3O-glucopyranoside flavone (quercetin 3-O-β-rhamnopyranoside) and 3,5,7,3’,4’-pentahydroxy flavones (quercetin). They were characterized with the help of ESI-MS, IR, 1 H C 13 , HMBC/HSQC and COSY-NMR data. These compounds did not show antibacterial activity when tested separately but exhibited appreciable antioxidant activities in different manner. Chromatographic fractionation of hexane extract of P. tomentosa resulted in the isolation of lupeol acetate (LA) with marginal but selective activity against M. luteus and the activity is due to LA rather than the combined constituents. These findings suggest that the fractions of the extracts and pure compounds possess antibacterial and antioxidant properties.

A Modified Method for Studying Behavioral Paradox of Antioxidants and Their Disproportionate Competitive Kinetic Effect to Scavenge the Peroxyl Radical Formation

We have described a modified method for evaluating inhibitor of peroxyl radicals, a well-recognized and -documented radical involved in cancer initiation and promotion as well as diseases related to oxidative stress and ageing. We are reporting hydrophilic and lipophilic as well as natural and synthetic forms of antioxidants revealing a diversified behaviour to peroxyl radical in a dose-dependent manner (1 nM–10 μM). A simple kinetic model for the competitive oxidation of an indicator molecule (ABTS) and a various antioxidant by a radical (ROO•) is described. The influences of both the concentration of antioxidant and duration of reaction (70 min) on the inhibition of the radical cation absorption are taken into account while determining the activity. The induction time of the reaction was also proposed as a parameter enabling determination of antioxidant content by optimizing and introducing other kinetic parameters in 96-well plate assays. The test evidently improves the original PRTC (peroxyl radical trapping capacity) assay in terms of the amount of chemical used, simultaneous tracking, that is, the generation of the radical taking place continually and the kinetic reduction technique (area under curve, peak value, slope, and V max).

Rutin protects t-butyl hydroperoxide-induced oxidative impairment via modulating the Nrf-2 and iNOS activity

BACKGROUND Rutin (quercetin-3-O-rutinoside), a flavonoid, is predominantly found in the buckwheat, cranberries, mulberry and citrus fruits. It is used as a restorative in the preparation of herbal medicine, multivitamin and known to reduce the fate of heart attack. HYPOTHESIS We aimed to elucidate whether rutin attenuates oxidative stress and its possible mechanism of action in ameliorating the deleterious effect of t-BHP. We also provide evidence that rutin protects the antioxidant status of erythrocytes and liver via Nrf2 and iNOS pathway from oxidative stress. STUDY DESIGN/METHOD Human erythrocytes and mice liver were used for the evaluation of rutins effect against t-BHP induced oxidative stress. The non-enzymatic (GSH, MDA, -CO, -SH) and enzymatic stress markers (SOD, CAT, GPx, GR and GST) were estimated by the colorimetric method. The level of Nrf2, iNOS, liver marker enzymes, triglycerides, cholesterol, HDL-cholesterol, albumin, BUN was measured using ELISA kits. Reactive oxygen species (ROS) was quantified using flow cytometry and fluorometry. RT-PCR was used for the quantification of Nrf2 and iNOS expression levels in the liver tissue of mice. In silico studies were done through receptor-ligand binding interaction. RESULTS Pre-treatment with the rutin ameliorated the toxic effect of t-BHP by modulating the basal level of GSH, -SH, MDA and -CO significantly (p < 0.01) with respect to untreated control. Rutin also protected the erythrocytes against the t-BHP-induced oxidative stress as evidenced by augmented activity of antioxidant enzymes (CAT, SOD, GPX, GR and GST). Furthermore, at the highest tested concentration (16.3 µM), it protected the morphology of the erythrocytes by decreasing the ROS level (p < 0.01). In addition, the lower MEF values of rutin (0.520 ± 0.005) alone or along with t-BHP (0.630 ± 0.021) indicated its non-toxic and protective behavior. The qPCR analyses revealed that t-BHP potently up-regulates the iNOS and down regulate the Nrf2 expression which was ameliorated with rutin treatment in a dose-dependent manner like silymarin. CONCLUSION Our findings demonstrate that rutin potentiates its beneficial aspect by displaying a profound role in iNOS-Nrf2 signaling pathway. Accordingly, it may be concluded that the dietary factors wherein rutin is an ingredient could be helpful in the maintenance of the intracellular redox-homeostasis and thus may be effective against oxidative stress related secondary complications.

Differential rubisco content and photosynthetic efficiency of rol gene integrated Vinca minor transgenic plant: Correlating factors associated with morpho-anatomical changes, gene expression and alkaloid productivity

Transgenic plants obtained from a hairy root line (PVG) of Vinca minor were characterized in relation to terpenoid indole alkaloids (TIAs) pathway gene expression and vincamine production. The hairy roots formed callus with green nodular protuberances when transferred onto agar-gelled MS medium containing 3.0mg/l zeatin. These meristematic zones developed into shoot buds on medium with 1.0mg/l 2, 4-dichlorophenoxyacetic acid and 40mg/l ascorbic acid. These shoot buds subsequently formed rooted plants when shifted onto a hormone-free MS medium with 6% sucrose. Transgenic nature of the plants was confirmed by the presence of rol genes of the Ri plasmid in them. The transgenic plants (TP) had elongated internodes and a highly proliferating root system. During glass house cultivation TP consistently exhibited slower growth rate, low chlorophyll content (1.02±0.08mg/gm fr. wt.), reduced carbon exchange rate (2.67±0.16μmolm-2s-1), less transpiration rate (2.30±0.20mmolm-2 s-1) and poor stomatal conductance (2.21±0.04mmolm-2 s-1) when compared with non-transgenic population. The activity of rubisco enzyme in the leaves of TP was nearly two folds less in comparison to non-transgenic controls (1.80milliunitsml-1mgprotein-1 against 3.61milliunits ml-1mgprotein-1, respectively). Anatomically, the TP had a distinct tetarch arrangement of vascular bundles in their stem and roots against a typical ployarched pattern in the non-transgenic plants. Significantly, the transgenic plants accumulated 35% higher amount of total TIAs (3.10±0.21% dry wt.) along with a 0.03% dry wt. content of its vasodilatory and nootropic alkaloid vincamine in their leaves. Higher productivity of alkaloids in TP was corroborated with more than four (RQ=4.60±0.30) and five (RQ=5.20±0.70) times over-expression of TIAs pathway genes tryptophan decarboxylase (TDC) and strictosidine synthase (STR) that are responsible for pushing the metabolic flux towards TIAs synthesis in this medicinal herb.

A Method for Measuring Difference in Activity of Phenolic and Non- Phenolic Groups Through 2,2` Azino-Bis-(3-Ethyl-Benzothiazoline-6- Sulphonate) Radical Cation

A 2, 2`azino-bis-(3-ethyl-benzothiazoline-6-sulphonate) radical cation-based method was optimized in 96 well plates to evaluate the comparative scavenging potential of phenolic and non-phenolic group of molecules with respect to control. The interactions of these molecules with ABTS radical cation were quantified on the basis of their relative influence on the bleaching of a bluish-green color complex in a structure- and dose-dependent manner. Experimentally, the developed assay provided evidence that phenolic molecules are more reactive with ABTS radical than non-phenolic compounds because of their resonance and hyper-conjugation effects.

Ornithine decarboxylase activity, a clinical biomarker for evaluating cancer chemopreventive efficacy of phytomolecules

Time (minutes)  A great no. of hurdles still abound in the use of ODC inhibitors, like DFMO as endpoints for chemoprevention clinical trials. Simply, ODC inhibitors may be used to prevent or slow the rate of tumour re-growth between doses of therapy with radiation or other more toxic chemotherapeutic agents. Continuous progress in cancer drug development will move from traditional cancer clinical trial to biomarker-driven and hypothesistesting trials . Also in near future some gaps in our knowledge of phytomolecules targeted cancer chemoprevention will close. Centtri Reaction Mixture L-Ornithine HCl β– mercaptoethanol EDTA Pyridoxal Phosphate