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Our laboratory documented progressive developments in our understanding of the unknown biological action of several classes of acetoxycoumarins (AC). These studies could be considered as significant from the point of view of unraveling the biological activity of AC for the first time when there was explosion of knowledge on the parent polyphenols alone.1) Firstly, 7,8-diacetoxy-4-methylcoumarin (DAMC) was found to interact with free radical resulting in the removal of acetyl group as the acetyl radical (CH 3 CO ϩ ) and the formation of phenoxyl radical as confirmed by pulse radiolysis.2) This finding accounted for the antioxidant action of AC independent of the formation of parent polyphenol 7,8-dihydroxy-4-methylcoumarin (DHMC). The observation that microsomes acted upon AC and caused the irreversible inhibition of several enzymes such as cytochrome P-450-linked mixed function oxidases (MFO) and the activation of nicotinamide adenine dinucleotide reduced (NADPH) cytochrome c reductase, prompted us to investigate the mode of action of AC.3) Further, detailed studies revealed the role of a unique enzyme (Fig. 1) catalyzing the transfer of acetyl group from AC to receptor proteins. 4,5) This enzyme was termed Acetoxy Drug: Protein Transacetylase (TAase), since the acetoxy derivatives of several classes of polyphenols were found to be substrates for TAase. [5][6][7][8] TAase from microsomes of rat and bovine liver as well as from human placenta were purified to homogeneity and its identity with the endoplasmic reticulum luminal protein Calreticulin (CR) was established and TAase was termed Calreticulin Transacetylase (CRTAase).9,10) In our earlier work, we have focused our attention on the role of CRTAase mediated acetylation of certain protein targets by acetoxycoumarins in the blood lymphocytes of asthmatic patients. We have demonstrated the irreversible inhibition of human blood lymphocyte Protein Kinase C (PKC) by way of acetylation. These studies revealed that several AC inhibited PKC of asthmatic patients.11) Several respiratory diseases such as coronary obstructive pulmonary diseases (COPD) and asthma are associated with hyperplasia and hypertrophy of airway smooth muscle. NO is strongly implicated in the amelioration of pathologies associated with the proliferation of airway smooth muscle cells. 12) Hence, it was thought interesting to investigate the influence of AC on tracheal smooth muscle cell (TSMC) NOS, with a view to highlight the possible application of AC in the management of airway diseases. The Transacetylase function of Calreticulin (CR) catalyzing the transfer of acetyl groups from acetoxycoumarins (AC) to certain proteins was identified for the first time in our laboratory. Protein acetyltransferase action of CR was termed Calreticulin Transacetylase (CRTAase). In the present work, CRTAase of rat tracheal smooth muscle cells (TSMC) was characterized with respect to the specificity for various AC and its role in the activation of nitric oxide synthase (NOS). 7,8-Diacetoxy-4-methylcoumarin (DAMC...

Nitric oxide (NO) is known to play an important role in the regulation of physiological functions. Various cell types are capable of synthesizing NO mainly from L-arginine with the participation of nitric oxide synthase (NOS). The action of NOS on L-arginine is the principal pathway to meet the tissue requirements of NO. The additional demand of NO in certain conditions of stress could be met by inducible nitric oxide synthase (iNOS). Several biological phenomena such as hypoxia is beset with the conditions where NOS is compromised, where the utilization of nitrates for the production of NO is encountered. 1) Nitrite reductase (NR) originally described in plants is discernible in microorganisms as well as mammalian cells. Panesar and Chan reported the NR activity in Mouse Leydig Tumor Cells and was attributed to mitochondrial respiratory chain complex III. Also, NO was found to be generated by the utilization of nitrite under basal conditions.2) Nitrate-NR system comprising of protein components such as pyridine nucleotides, flavoproteins and cytochromes are reported to be present in the mitochondria as well as the endoplasmic reticulum for the purpose of NO formation.1) In addition nitrite can function as a signaling molecule independent of the formation of NO.3) The oxidoreductase such as the cytochrome P-450 reductase (CYPR) is known to reduce inorganic nitrate to nitrite and then to NO. The reduction of nitrite to NO is ascribed to various factors including mitochondrial enzymes, polyphenols and protons. Keeping in view of the cardinal role played by NO in the physiology of the organisms it has become necessary to study the formation of nitrite and conversion to NO. It is worth mentioning that nitrate, mimics the role of NO in conditions such as normoxia and ischemic-reperfusion. 4) NO generated by reduction of nitrite by enzymes of cytochrome P-450 family is also responsible for the activation of cyclic guanosine monophosphate (cGMP) signaling pathway. 5,6) The extensive investigations carried out in our laboratory deciphered the identity of TAase with Calreticulin (CRT), a resident protein of the endoplasmic reticulum and consequently the TAase was given a name "Calreticulin transacetylase" (CRTAase). 7) Earlier work from our laboratory highlighted the presence of CRTAase in human platelets and activation of platelets NOS by polyphenolic acetates (PA) catalyzed by CRTAase.8) Purified human placental CRTAase mediated acetylation of neuronal nitric oxide synthax (nNOS) by 7,8-diacetoxy-4-methylcoumarin (DAMC) was demonstrated. 9)Our earlier investigations strongly indicated the CRTAase

The quality of ground water in any region of the world entirely depends on different types of chemical constituents and their concentration levels in surrounding environment or dissolved in water. The main aim of this study was to assess some basic hydro-chemical parameters and heavy metals in ground water of National Capital Region (NCR), India. Thus, we have collected ground water samples from different sources viz., Najafargarh (NG), Bindapur (BP), Dwarka (BC and BG), Uttam Nagar (UN) and Sonipat (SP) in the NCR and analyzed electrical conductivity (EC), total dissolved solids (TDS), salinity, Arsenic (As), Chromium (Cr), Copper (Cu), Cadmium (Cd), Nickel (Ni), Zinc (Zn), and Lead (Pb). The values of EC, TDS and salinity across the study sites range from 0.32 to 11.41 mS/cm, 233 to 8100 ppm and 154 to 6310 ppm respectively. Whereas, the mean level of heavy ion concentration in ground water was in the sequence of Zn > Ni > Cr > Pb > As > Cu > Cd across the study sites. It has been concluded that, except for Uttam Nagar, ground water from all study sites is contaminated with heavy metals like Zn, Ni, Cr, Pb and As. Therefore, the ground water from study sites that are polluted is unfit for drinking purpose and may pose health risks.

The potential role of polyphenolic acetate (PA) in causing diverse biological and pharmacological actions has been well studied in our laboratory. Our investigations, for the first time, established the role of calreticulin transacetylase (CRTAase) in catalyzing the acetylation of nitric oxide synthase (NOS) by Pas leading to robust activation of NOS. 7, 8- Diacetoxy-4-methylcoumarin (DAMC) and other acetoxycoumarins augmented the expression of thioredoxin (TRX) and vascular endothelial growth factor (VEGF) in human peripheral blood mononuclear cells (PBMCs). These findings substantiated our earlier observations that DAMC was a superb inducer of angiogenesis. The enhanced expression of thioredoxin reductase (TRXR) and diminished expression of thioredoxin interacting protein (TRXIP) leading to increased expression and activity of TRX in PBMCs due to the action of DAMC was revealed by real time RT-PCR analysis. The possible activation of TRX due to acetylation was confirmed by the fact that TRX activity of PBMCs was enhanced by various acetoxycoumarins in tune with their affinities to CRTAase as substrates. DAMC caused enhanced production of NO by way of acetylation of NOS as mentioned above and thereby acted as an inducer of VEGF. Real time RT-PCR and VEGF ELISA results also revealed the overexpression of TRX. DAMC and other PAs were found to reduce the oxidative stress in cells as proved by significant reduction of intracellular ROS levels. Thus, the crucial role of TRX in DAMC-induced angiogenesis with the involvement of VEGF was established.

Fresh produce available in an area is the major source of phytonutrients for healthy life. Decrease in the concentration of phytonutrients is directly linked to a range of health issues in terms of increase in the rate of infections. This study conducted on fresh produce available in Delhi and National Capital Region (NCR) on microbiological and nutritional analysis showed a significant increase in microbial load in fruits as they stay over the period of a week to fortnight at room temperature. A total of seven different types of fresh produce were procured for analysis. Out of them, lemon showed the lowest microbial count and sugar content and grapes showed highest microbial count and sugar content. Results were also compared with refrigerated and room temperature stored fruits. It was concluded that fresh fruits have more nutritive value than stored fruits (room and refrigerated). In this study, glucose content was determined by Fehling's titration and Ascorbic Acid by Dichlorophenolindophenol method. The microbial biota was assessed by serial dilution method for determining microbial load of different types of bacteria. Some of the fruits showed decrease in the nutritive value and correspondingly increase in the load of antibiotic resistant microbes during storage rendering them unfit for human consumption.