Elemental Composition and Sources of Fine Particulate Matter (PM2.5) in Delhi, India

In this study we have analysed the elemental composition of fine particulate matter (PM_2.5) to examine the seasonal changes and sources of the elements in Delhi, India from January, 2017 to December, 2021. During the entire sampling period, 19 elements (Al, Fe, Ti, Cu, Zn, Cr, Ni, As, Mo, Cl, P, S, K, Pb, Na, Mg, Ca, Mn, and Br) of PM_2.5 were identified by Wavelength Dispersive X-ray Fluorescence Spectrometer. The higher annual mean concentrations of S (2.29 µg m^-3), Cl (2.26 µg m^-3), K (2.05 µg m^-3), Ca (0.96 µg m^-3) and Fe (0.93 µg m^-3) were recorded during post-monsoon season followed by Zn > Pb > Al > Na > Cu > Ti > As > Cr > Mo > Br > Mg > Ni > Mn > and P. The annual mean concentrations of elemental composition of PM_2.5 accounted for 10% of PM_2.5 (pooled estimate of 5 year). Principal Component Analysis (PCA) identified the five main sources [crustal/soil/road dust, combustion (BB + FFC), vehicular emissions (VE), industrial emissions (IE) and mixed source (Ti, Cr and Mo rich-source)] of PM_2.5 in Delhi, India.

Long-Term Variation in Carbonaceous Components of PM2.5 from 2012 to 2021 in Delhi

Carbonaceous species [organic carbon (OC), elemental carbon (EC), elemental matter (EM), primary organic carbon (POC), secondary organic carbon (SOC), total carbon (TC), and total carbonaceous matter (TCM)] of PM_2.5 were analyzed to study the seasonal variability and long-term trend of carbonaceous aerosols (CAs) in megacity Delhi, India from January, 2012 to April, 2021. The average concentrations (± standard deviation) of PM_2.5, OC, EC, TC, EM, TCM, POC and SOC were 127 ± 77, 15.7 ± 11.6, 7.4 ± 5.1, 23.1 ± 16.5, 8.2 ± 5.6, 33.3 ± 23.9, 9.3 ± 6.3 and 6.5 ± 5.3 µg m^-3, respectively during the sampling period (10-year average). The average CAs accounted for 26% of PM_2.5 concentration during the entire sampling period. In addition, the seasonal variations in PM_2.5, OC, EC, POC, SOC, and TCM levels were recorded with maxima in post-monsoon and minima in monsoon seasons. The linear relationship of OC and EC, OC/EC and EC/TC ratios suggested that the vehicular emissions (VE), fossil fuel combustion (FFC) and biomass burning (BB) are the major sources of CAs at megacity Delhi, India.

Synthesis of novel Co3O4 nanocubes-NiO octahedral hybrids for electrochemical energy storage supercapacitors

Fabrication of novel metal oxide nanostructured composites is a proficient approach to develop efficient energy storage devices and development of cost-free and eco-friendly metal oxide nanostructures for supercapacitor applications received considerable attention in recent years. The Co₃O₄ nanocubes-NiO octahedral structured composite was constructed using facile and one-step calcination process. Cyclic voltammetry, charge-discharge, and electrochemical impedance spectral techniques have been employed to analyze the specific capacitance of the synthesized nanostructures and the composites. Specific capacitance and cycling stability of the composites were evaluated with the pristine Co₃O₄ and NiO nanostructures. The composite showed a specific capacitance of 832 F g^-1 at a current density of 0.25 A g^-1, which was ~1.5 and ~1.9-times higher than pristine Co₃O₄ nanocubes and NiO octahedral structure, respectively. On the other hand, electrode showed approximately 50 % capacity retention at a higher current density (5 Ag^-1) because of the uniform morphology of Co₃O₄ and NiO. The charge-discharge stability measurements of the composite showed an admirable specific capacitance retention capability, which was 94.5 % after 2000 continuous charge-discharge cycles at a current density of 5 A g^-1. The superior electrochemical performance of the nano-composite was ascribed to synergistic effects and uniform morphology. Efficient nanostructure development using facile and one-step calcination process and electrochemical performance make the synthesized composite a promising device for supercapacitor applications.

Intervention of Ayurvedic drug Tinospora cordifolia attenuates the metabolic alterations in hypertriglyceridemia: a pilot clinical trial

Purpose

Hypertriglyceridemia (HG) is an independent risk factor with more prevalence than hypercholesterolemia and its attributes to cardiovascular disease (CVD) and pancreatitis. Hence, it becomes imperative to search for new triglyceride (TG) lowering agents. Tinospora cordifolia (TC) is a well-known Ayurvedic drug and a rich source of protoberberine alkaloids hence can contribute to TG lowering without side effects. Hence, to explore the therapeutic efficacy of T. cordifolia and its effects on biochemistry and metabolome in the patients of hyper-triglyceridemia, clinical trials were conducted.

Methods

Patients (n = 24) with hypertriglyceridemia were randomized into two groups to receive T. cordifolia extract (TCE) (3.0 g/per day) and metformin (850 mg/day) for 14 days having >300 mg/dl triglyceride level and cholesterol in the range of 130-230 mg/dl. Lipid profiles of blood samples were analyzed. Urine samples were subjected to HPLC-QTOF-MS to quantify oxidative damage and abnormal metabolic regulation.

Results

Intervention with TCE reduced the triglyceride, LDL, and VLDL levels to 380.45 ± 17.44, 133.25 ± 3.18, and 31.85 ± 5.88 mg/dL and increased the HDL to 47.50 ± 9.05 mg/dL significantly (p < 0.05) in the HG patients after 14 days treatment. TCE dosage potently suppressed the inflammatory and oxidative stress marker's i.e. levels of isoprostanes significantly (p < 0.01). Qualitative metabolomics approach i.e. PCA and PLS-DA showed significant alterations (p < 0.05) in the levels of 40 metabolites in the urine samples from different groups.

Conclusion

TCE administration depleted the levels of markers of HG i.e. VLDL, TG, and LDL significantly. Metabolomics studies established that the anti-HG activity of TCE was due to its antioxidative potential and modulation of the biopterin, butanoate, amino acid, and vitamin metabolism.

Clinical trials registry

India (CTRI) registration no. CTRI- 2016-08-007187.

Seasonal characteristics of aerosols (PM2.5 and PM10) and their source apportionment using PMF: A four year study over Delhi, India

The present study attempts to explore and compare the seasonal variability in chemical composition and contributions of different sources of fine and coarse fractions of aerosols (PM_2.5 and PM₁₀) in Delhi, India from January 2013 to December 2016. The annual average concentrations of PM_2.5 and PM₁₀ were 131 ± 79 μg m^-3 (range: 17-417 μg m^-3) and 238 ± 106 μg m^-3 (range: 34-537 μg m^-3), respectively. PM_2.5 and PM₁₀ samples were chemically characterized to assess their chemical components [i.e. organic carbon (OC), elemental carbon (EC), water soluble inorganic ionic components (WSICs) and heavy and trace elements] and then used for estimation of enrichment factors (EFs) and applied positive matrix factorization (PMF5) model to evaluate their prominent sources on seasonal basis in Delhi. PMF identified eight major sources i.e. Secondary nitrate (SN), secondary sulphate (SS), vehicular emissions (VE), biomass burning (BB), soil dust (SD), fossil fuel combustion (FFC), sodium and magnesium salts (SMS) and industrial emissions (IE). Total carbon contributes ∼28% to the total PM_2.5 concentration and 24% to the total PM₁₀ concentration and followed the similar seasonality pattern. SN and SS followed opposite seasonal pattern, where SN was higher during colder seasons while SS was greater during warm seasons. The seasonal differences in VE contributions were not very striking as it prevails evidently most of year. Emissions from BB is one of the major sources in Delhi with larger contribution during winter and post monsoon seasons due to stable meteorological conditions and aggrandized biomass burning (agriculture residue burning in and around the regions; mainly Punjab and Haryana) and domestic heating during the season. Conditional Bivariate Probability Function (CBPF) plots revealed that the maximum concentrations of PM_2.5 and PM₁₀ were carried by north westerly winds (north-western Indo Gangetic Plains of India).

Emergence of Blue Sky Over Delhi Due to Coronavirus Disease (COVID-19) Lockdown Implications

Due to coronavirus pandemic (COVID-19) prevailing in more than 210 countries, out of them only few have promulgated lockdown and on March 24, 2020 India also implemented lockdown for 21 days to prevent the community spread of virus among people. Since then, lockdown heavily restricts travel movements of flights, rail, intercity bus services besides industrial activity halt throughout the country. The significant improvement in the air quality of Delhi region was observed due to strict implementation of lockdown. During the lockdown period, improvement in ambient air quality helped us in circumventing the coronavirus community spread. The preliminary results showing the decrease in horizontal advection of pollutants has given an opportunity to understand the background concentrations of air pollutants over Delhi. To analyse this peculiar situation, we have assessed the pollutants datasets collected by twelve different online ambient air quality monitoring stations (AQMS) of Central Pollution Control Board (CPCB), New Delhi, India and observed a colossal improvement in the ambient air quality. The analysis of data confirms the sharp decline in concentrations (nearly 200%) of PM_2.5 and PM₁₀. The concentration of nitrous oxides (NO_x), recorded its maximum (342 ppb) on 12 January 2020 in CRRI–Mathura Road, Delhi with the lowest value as 24 ppb on 30 March 2020 (reduced to nearly 14 times of the peak value). In the triad of this infectious disease, the role of environment is not linked better however, the ground reality cannot be ignored due to environment around us receives, maintains, protects and transports the aetiological agents to host prevailing in polluted environment which makes our lungs more susceptible to viral attacks. Therefore, a cleaner environment would prove to be an effective measure to halt and reduce the transmission of viral infections.

Influence of Vehicular Emissions (NO, NO2, CO and NMHCs) on the Mixing Ratio of Atmospheric Ammonia (NH3) in Delhi, India

Mixing ratios of atmospheric ammonia (NH₃), nitric oxide (NO), carbon monoxide (CO), nonmethane hydrocarbons (NMHCs), and methane (CH₄) were measured to investigate the vehicular emissions, which are a dominant source of atmospheric NH₃ in urban sites of Delhi, India from January 2013 to December 2014. The annual average mixing ratios of NH₃, NO, CO, NMHCs, and CH₄ were 21.2 ± 2.1 ppb, 21.2 ± 6.1 ppb, 1.89 ± 0.18 ppm, 0.67 ± 0.21 ppm and 3.11 ± 0.53 ppm, respectively. Considering NO as a tracer of vehicular plume, ambient NH₃ was correlated with NO during peak traffic hour in the morning (7:00-10:00 h) and evening (17:00-19:00 h) and observed significant positive correlation between them. Result reveals that the mixing ratio of atmospheric NH₃ significantly positive correlated with traffic related pollutants (NO, CO, and NHHCs) during all the seasons (winter, summer, and monsoon). During winter, the average mixing ratio of atmospheric NH₃ was increased by 1.2-3.5 ppb in the morning peak hour, whereas increased by 0.3-1.6 ppb in the evening peak hour. Similarly, an increase in NH₃ mixing ratio was observed during summer (morning: 1.2-2.7 ppb and evening: 1.5-1.6 ppb) and monsoon (morning: 0.4-3.6 ppb and evening: 0.9-1.4 ppb) seasons. The results emphasized that the traffic could be one of the dominant source of ambient NH₃ at the urban site of Delhi, as illustrated by positive relationships of NH₃ with traffic related co-pollutants (NO, CO and NMHCs).

Carbonaceous Species of PM2.5 in Megacity Delhi, India During 2012-2016

Organic carbon (OC) and elemental carbon (EC) in PM_2.5 were estimated to study the seasonal and inter-annual variability of atmospheric total carbonaceous aerosols (TCA) at an urban site of megacity Delhi, India for 5 years from January, 2012 to December, 2016. The annual average (± standard deviation) concentrations of PM_2.5, OC, EC and TCA were 128 ± 81, 16.6 ± 12.2, 8.4 ± 5.8 and 34.5 ± 25.2 µg m^-3, respectively. During the study, significant seasonal variations in mass concentrations of PM_2.5, OC, EC and TCA were observed with maxima in winter and minima in monsoon seasons. Significant correlations between OC and EC, and OC/EC ratio suggested that vehicular emissions, fossil fuel combustion and biomass burning could be major sources of carbonaceous aerosols of PM_2.5 at the sampling site of Delhi, India.

Inter-annual Variation of Ambient Ammonia and Related Trace Gases in Delhi, India

In this study, ambient NH₃, NO, NO₂, CO and SO₂ were measured continuously from February, 2008, to December, 2016. The annual average mixing ratios (mole/mole) of NH₃, NO, NO₂, CO and SO₂ were 17.8 ± 3.4 ppb; 21.2 ± 2.3 ppb, 18.1 ± 3.2 ppb; 1.7 ± 0.3 ppm and 2.0 ± 0.3 ppb, respectively. All the trace gases (NH₃, NO, NO₂, CO and SO₂) showed significant annual variation during the study. A significant increasing trend in mixing ratios of ambient NH₃ and NO₂ were observed at the observational site of Delhi, whereas, increasing trend were recorded in case of NO, CO and NO₂ mixing ratios. The results emphasized that traffic could be one of the significant sources of ambient NH₃ at the urban site of Delhi, as illustrated by positive correlations of NH₃ with traffic related co-pollutants (NO and CO).

Seasonal variations and source profile of n-alkanes in particulate matter (PM10) at a heavy traffic site, Delhi

Delhi is one of the most polluted cities in the world. The generation of aerosols in the lower atmosphere of the city is mainly due to a large amount of natural dust advection and sizable anthropogenic activities. The compositions of organic compounds in aerosols are highly variable in this region and need to be investigated thoroughly. Twenty-four-hour sampling to assess concentrations of n-alkanes (ng/m³) in PM₁₀ was carried out during January 2015 to June 2015 at Indira Gandhi Delhi Technical University for Women (IGDTUW) Campus, Delhi, India. The total average concentration of n-alkanes, 243.7 ± 5.5 ng/m³, along with the diagnostic tools has been calculated. The values of CPI₁, CPI₂, and CPI₃ for the whole range of n-alkanes series, petrogenic n-alkanes, and biogenic n-alkanes were 1.00, 1.02, and 1.04, respectively, and C _max were at C₂₅ and C₂₇. Diagnostic indices and curves indicated that the dominant inputs of n-alkanes are from petrogenic emissions, with lower contribution from biogenic emissions. Significant seasonal variations were observed in average concentrations of n-alkanes, which is comparatively higher in winter (187.4 ± 4.3 ng/m³) than during the summer season (56.3 ± 1.1 ng/m³).

Seasonal characteristics of water-soluble inorganic ions and carbonaceous aerosols in total suspended particulate matter at a rural semi-arid site, Kadapa (India)

To better understand the sources as well as characterization of regional aerosols at a rural semi-arid region Kadapa (India), size-resolved composition of atmospheric particulate matter (PM) mass concentrations was sampled and analysed. This was carried out by using the Anderson low-pressure impactor for a period of 2 years during March 2013-February 2015. Also, the variations of organic carbon (OC), elemental carbon (EC) and water-soluble inorganic ion components (WSICs) present in total suspended particulate matter (TSPM) were studied over the measurement site. From the statistical analysis, the PM mass concentration showed a higher abundance of coarse mode particles than the fine mode during pre-monsoon season. In contrast, fine mode particles in the PM concentration showed dominance over coarse mode particle contribution during the winter. During the post-monsoon season, the percentage contributions of coarse and fine fractions were equal, whereas during the monsoon, coarse mode fraction was approximately 26 % higher than the fine mode. This distinct feature in the case of fine mode particles during the studied period is mainly attributed to large-scale anthropogenic activities and regional prevailing meteorological conditions. Further, the potential sources of PM have been identified qualitatively by using the ratios of certain ions. A high sulphate (SO₄) concentration at the measurement site was observed during the studied period which is caused by the nearby/surrounding mining activity. Carbon fractions (OC and EC) were also analysed from the TSPM, and the results indicated (OC/EC ratio of ~4.2) the formation of a secondary organic aerosol. At last, the cluster backward trajectory analyses were also performed at Kadapa for different seasons to reveal the origin of sources from long-range transport during the study period.

Spatio-temporal variation in chemical characteristics of PM10 over Indo Gangetic Plain of India

The paper presents the spatio-temporal variation of chemical compositions (organic carbon (OC), elemental carbon (EC), and water-soluble inorganic ionic components (WSIC)) of particulate matter (PM10) over three locations (Delhi, Varanasi, and Kolkata) of Indo Gangetic Plain (IGP) of India for the year 2011. The observational sites are chosen to represent the characteristics of upper (Delhi), middle (Varanasi), and lower (Kolkata) IGP regions as converse to earlier single-station observation. Average mass concentration of PM10 was observed higher in the middle IGP (Varanasi 206.2 ± 77.4 μg m(-3)) as compared to upper IGP (Delhi 202.3 ± 74.3 μg m(-3)) and lower IGP (Kolkata 171.5 ± 38.5 μg m(-3)). Large variation in OC values from 23.57 μg m(-3) (Delhi) to 12.74 μg m(-3) (Kolkata) indicating role of formation of secondary aerosols, whereas EC have not shown much variation with maximum concentration over Delhi (10.07 μg m(-3)) and minimum over Varanasi (7.72 μg m(-3)). As expected, a strong seasonal variation was observed in the mass concentration of PM10 as well as in its chemical composition over the three locations. Principal component analysis (PCA) identifies the contribution of secondary aerosol, biomass burning, fossil fuel combustion, vehicular emission, and sea salt to PM10 mass concentration at the observational sites of IGP, India. Backward trajectory analysis indicated the influence of continental type aerosols being transported from the Bay of Bengal, Pakistan, Afghanistan, Rajasthan, Gujarat, and surrounding areas to IGP region.

Source Apportionment of PM2.5 in Delhi, India Using PMF Model

Chemical characterization of PM2.5 [organic carbon, elemental carbon, water soluble inorganic ionic components, and major and trace elements] was carried out for a source apportionment study of PM2.5 at an urban site of Delhi, India from January, 2013, to December, 2014. The annual average mass concentration of PM2.5 was 122 ± 94.1 µg m(-3). Strong seasonal variation was observed in PM2.5 mass concentration and its chemical composition with maxima during winter and minima during monsoon. A receptor model, positive matrix factorization (PMF) was applied for source apportionment of PM2.5 mass concentration. The PMF model resolved the major sources of PM2.5 as secondary aerosols (21.3 %), followed by soil dust (20.5 %), vehicle emissions (19.7 %), biomass burning (14.3 %), fossil fuel combustion (13.7 %), industrial emissions (6.2 %) and sea salt (4.3 %).

Variation of Stable Carbon and Nitrogen Isotopic Composition of PM10 at Urban Sites of Indo Gangetic Plain (IGP) of India

This paper presents the variation of elemental concentrations of total carbon (TC), total nitrogen (TN) and isotopic ratios of δ13C and δ15N along with δ13OC and OC of PM10 mass over Delhi, Varanasi and Kolkata of the Indo Gangetic Plain (IGP), India. For Delhi, the average concentrations of TC and TN of PM10 were 53.0±33.6 and 14.9±10.8 µg m(-3), whereas δ13C and δ15N of PM10 were -25.5±0.5 and 9.6±2.8‰, respectively. For Varanasi, the average values of δ13C and δ15N of PM10 were -25.4±0.8 and 6.8±2.4‰, respectively. For Kolkata, TC and TN values for PM10 ranged from 9.1-98.2 to 1.4-25.9 µg m(-3), respectively with average values of 32.6±24.9 and 9.3±8.2 µg m(-3), respectively. The average concentrations of δ13C and δ15N were -26.0±0.4 and 7.4±2.7‰, respectively over Kolkata with ranges of -26.6 to -24.9‰ and 2.8±11.5‰, respectively. The isotopic analysis revealed that biomass burning, vehicular emission and secondary inorganic aerosols were likely sources of PM10 mass over IGP, India.

Air Quality Indices: A Literature Review

Air quality indices are commonly used to indicate the level of severity of air pollution to the public. It is infeasible and perhaps impossible to formulate a universal technique for determining air quality index, one that considers all pollutants and that is appropriate for all situations. The intended use of the air quality index is to identify the vulnerable zone. There are mainly two approaches viz. single pollutant index and multi-pollutant index to determine the air quality index. Every index has its own characteristic strengths and weaknesses that affect its suitability for particular applications. This paper attempts to present a review of all the major air quality indices developed worldwide.

Disposition kinetics of sparfloxacin in healthy, hepatopathic, and nephropathic conditions in chicken after single intravenous administration

OBJECTIVE

To study the variation of disposition kinetic values of sparfloxacin in healthy, hepatopathic, and nephropathic chickens after a single intravenous administration.

MATERIALS AND METHODS

Hepatotoxicity was induced by the administration of paracetamol (500 mg / kg / day, p.o. for seven days) and nephrotoxicity by uranyl nitrate (2.0 mg / kg / day dissolved in distilled water, i.v. for four days) in chickens. Disposition kinetic studies of sparfloxacin were investigated in healthy as well as hepatopathic and nephropathic birds after a single intravenous administration at 40 mg / kg body weight.

RESULTS

Maximum plasma concentration detected at 0.16 hour was 31.25 +/- 2.95, 61.95 +/-1.85, and 99.86 +/- 2.21 mug / ml in healthy, hepatopathic, and nephropathic group, respectively. The drug could not be detected in the plasma of healthy birds beyond 12-hour period, while the same was detectable for 72 hour in the plasma of hepatopathic and nephropathic birds. The concentration of sparfloxacin was significantly (P < 0.01) higher in all the samples of hepathopathic and nephropathic birds compared to healthy birds. All the kinetic values were increased (P < 0.01) in the hepatopathic and nephropathic birds, except Vd(area) and Cl(B) values in hepatopathic Birds; while beta and Cl(B) values nephropathic birds were decreased significantly than that of healthy birds.

CONCLUSIONS

The dose of sparfloxacin may be reduced in hepatopathic as well as nephropathic birds.

Study of temporal variation in ambient air quality during Diwali festival in India

The variation in air quality was assessed from the ambient concentrations of various air pollutants [total suspended particle (TSP), particulate matter < or =10 microm (PM(10)), SO(2), and NO(2)] for pre-Diwali, Diwali festival, post-Diwali, and foggy day (October, November, and December), Delhi (India), from 2002 to 2007. The extensive use of fireworks was found to be related to short-term variation in air quality. During the festival, TSP is almost of the same order as compared to the concentration at an industrial site in Delhi in all the years. However, the concentrations of PM(10), SO(2), and NO(2) increased two to six times during the Diwali period when compared to the data reported for an industrial site. Similar trend was observed when the concentrations of pollutants were compared with values obtained for a typical foggy day each year in December. The levels of these pollutants observed during Diwali were found to be higher due to adverse meteorological conditions, i.e., decrease in 24 h average mixing height, temperature, and wind speed. The trend analysis shows that TSP, PM(10), NO(2), and SO(2) concentration increased just before Diwali and reached to a maximum concentration on the day of the festival. The values gradually decreased after the festival. On Diwali day, 24-h values for TSP and PM(10) in all the years from 2002 to 2007 and for NO(2) in 2004 and 2007 were found to be higher than prescribed limits of National Ambient Air Quality Standards and exceptionally high (3.6 times) for PM(10) in 2007. These results indicate that fireworks during the Diwali festival affected the ambient air quality adversely due to emission and accumulation of TSP, PM(10), SO(2), and NO(2).

Study on concentration of ambient NH3 and interactions with some other ambient trace gases

We present diurnal variation of ambient ammonia (NH(3)) in relation with other trace gases (O(3), CO, NO, NO(2), and SO(2)) and meteorological parameters at an urban site of Delhi during winter period. For the first time, ambient ammonia (NH(3)) was monitored very precisely and continuously using ammonia analyzer, which operates on chemiluminescence method. NH(3) estimation efficiency of the chemiluminescence method (>90%) is much higher than the conventional chemical trapping method (reproducibility 4.5%). Ambient NH(3) concentration reaches its maxima (46.17 ppb) at night and minimum during midday. Result reveals that the ambient ammonia (NH(3)) concentration is positively correlated with ambient NO (r(2) = 0.79) and NO(2) (r (2) = 0.91) mixing ratio and negatively correlated with ambient temperature (r(2) = - 0.32). Wind direction and wind speed indicates that the nearby (approximately 500 m NW) agricultural fields may be major source of ambient NH(3) at the observational site.

Seasonal variability of ambient NH3, NO, NO2 and SO2 over Delhi

We present the diurnal and seasonal variability of ambient NH3, NO, NO2 and SO2 over Delhi, India. Ambient NH3, NO and NO2 were measured continuously during winter, summer and autumn seasons using NH3- and NOx-analyzer, which operates by chemiluminescence method with a higher estimation efficiency (> 90%) than the chemical trap method (reproducibility 4.7%). Prominent diurnal, day-to-day and seasonal variations of ambient mixing ratio of NH3, NO, NO2 and SO2 were observed during the study period. Seasonal variation with higher mixing ratio in winter was observed for all measured trace gases except NO. Day-night variation of all measured trace gases observed was higher in winter in comparison with summer. Late morning increase in NO2 mixing ratio might be attributed to conversion of NO to NO2 with the interaction of O3.

Radioprotection in mice following oral delivery of amifostine nanoparticles

PURPOSE

Amifostine (Ethyol) is an approved cytoprotective agent prescribed to reduce certain side-effects in the chemotherapy of ovarian or non-small cell lung cancer, or in radiation treatment of head-and-neck cancer. The usefulness of this drug is further hampered, because it is not effective when given orally. The objective of this part of the project was to evaluate the radioprotective efficacy of orally active amifostine nanoparticles.

MATERIALS AND METHODS

Radioprotective efficacy was evaluated by measuring the ability of the amifostine nanoparticles (equivalent to 500 mg/Kg) to inhibit whole-body gamma irradiation -induced injury in mice. All mice received acute whole-body gamma irradiation from a Cesium-137 source and the radioprotective efficacy of the formulation was determined by measuring 30-day survival at 9 Gy, bone marrow hemopoeitic progenitor cell survival at 9 Gy and 8 Gy, and intestinal crypt cell survival at 11 Gy.

RESULTS

Thirty-day survival, hemopoietic progenitor cell survival, as well as the jejunal crypt cell survival were all significantly enhanced when the mice were treated orally with the amifostine nanoparticles 1 h prior to irradiation.

CONCLUSIONS

These results clearly and unequivocally demonstrate that the amifostine nanoparticles developed in our laboratory provides significant protection from acute whole-body gamma irradiation injury in mice.

Natural products--antifungal agents derived from plants

A new spectrum of human fungal infections is increasing due to increased cancer, AIDS, and immunocompromised patients. The increased use of antifungal agents also resulted in the development of resistance to the present drugs. It makes necessary to discover new classes of antifungal compounds to cure fungal infections. Plants are rich source of bioactive secondary metabolites of wide variety such as tannins, terpenoids, saponins, alkaloids, flavonoids, and other compounds, reported to have in vitro antifungal properties. Since the plant kingdom provides a useful source of lead compounds of novel structure, a wide-scale investigation of species from the tropics has been considered. Therefore, the research on natural products and compounds derived from natural products has accelerated in recent years due to their importance in drug discovery. A series of molecules with antifungal activity against different strains of fungus have been found in plants, which are of great importance to humans. These molecules may be used directly or considered as a precursor for developing better molecules. This review attempts to summarize the current status of important antifungal compounds from plants.

In vitro and in vivo antimicrobial activities of seeds of Caesalpinia bonduc (Lin.) Roxb

AIM OF THE STUDY

Caesalpinia bonduc (Lin.) Roxb. is a known drug in Ayurveda to treat various diseases specifically tumors, cysts and cystic fibrosis (CF). The aim of this study was to assess in vitro as well as in vivo antimicrobial activity of Caesalpinia bonduc seeds.

MATERIALS AND METHODS

The in vitro antimicrobial activities of seed coat and seed kernel extracts were investigated by microbroth dilution assay. In vivo activities of hydro-alcoholic extracts were investigated in rat models of chronic Pseudomonas aeruginosa pneumonia mimicking that in patients with cystic fibrosis.

RESULTS

Various extracts of plant seeds exhibited in vitro antimicrobial activities in a range of 22-350 microg/ml. The extracts also showed activity against methicillin resistant (MR) Staphylococcus aureus and ampicillin resistant (AR) Pseudomonas aeruginosa as in the sensitive strains. In rat model of chronic Pseudomonas aeruginosa pneumonia, hydro-alcoholic extracts of Caesalpinia bonduc seed kernel (CBSK) and Caesalpinia bonduc seed coat (CBSC) were injected subcutaneously in the test groups of animals. The control groups were treated with cortisone and saline. Two weeks after challenge with Pseudomonas aeruginosa, the CBSK treated animals showed a significant bacterial clearance from the lungs (P<0.04) and less severe incidence of lung abscess (P<0.05).

CONCLUSION

Results showed that Caesalpinia bonduc may have the potential to be promising natural medicine, with other forms of treatments, for CF patients with chronic Pseudomonas aeruginosa lung infections.

Post-antifungal effects of the antifungal compound 2-(3,4-dimethyl-2,5-dihydro-1H-pyrrol-2-yl)-1-methylethyl pentanoate on Aspergillus fumigatus

The post-antifungal effect (PAFE) of the antifungal compound 2-(3,4-dimethyl-2,5-dihydro-1H-pyrrol-2-yl)-1-methylethyl pentanoate (DHP) upon Aspergillus fumigatus was investigated. The conidia of A. fumigatus were exposed to DHP at concentrations of 1× and 4× MIC90 for variable times at 37 °C. Amphotericin B (AmB)-treated or drug-free controls were included in the study. DHP as well as AmB exposure resulted in prolonged lag phases of the turbidimetric growth curves. Both the treatments gave rise to delayed growth, with lag phases of 11 h upon treatment with a concentration of 4× MIC90 for 4 h. Furthermore, it was observed that DHP inhibited the expression of three A. fumigatus secretory proteins of 18, 42 and 55 kDa. One protein of 42 kDa was found to be a metalloprotease, which is an important virulence factor. Analysis of time-dependent antigenic profiles showed the early expression of high-molecular-mass antigens. Expression of low-molecular-mass antigens started after 24 h culture. The antigens of A. fumigatus that are expressed during the early phase of growth were observed to be adversely affected after treatment with DHP. Although the mechanism of action of DHP to inhibit these proteins/antigens is unknown, the observations may be valuable to understand their role in the virulence of the pathogen, as well as the antigen-mediated responses caused by A. fumigatus.

Antimicrobial activity of some Indian medicinal plants

The antimicrobial potential of seventy-seven extracts from twenty-four plants was screened against eight bacteria and four pathogenic fungi, using microbroth dilution assay. Lowest concentration of the extract, which inhibits any visual microbial growth after treatment with p-iodonitrotetrazolium violet, was considered to be minimum inhibitory concentration (MIC). Water extracts of Acacia nilotica, Justicia zelanica, Lantana camara and Saraca asoca exhibited good activity against all the bacteria tested and the MIC was recorded in range of 9.375-37.5 microg/ml and 75.0-300.0 microg/ml against the bacterial and fungal pathogens, respectively. The other extracts of Phyllanthus urinaria, Thevetia nerifolia, Jatropha gossypifolia Saraca asoca, Tamarindus indica, Aegle marmelos, Acacia nilotica, Chlorophytum borivilianum, Mangifera indica, Woodfordia fruticosa and Phyllanthus emblica showed antimicrobial activity in a range of 75-1200 microg/ml.

Neuropharmacological effects of deltamethrin in rats

This study examined the effect of deltamethrin on some of the neuropharmacological paradigms in a rat brain such as the motor co-ordination test using a rotarod, the pentobarbitone-induced sleeping time and pentylenetetrazole (PTZ)-induced convulsion as well as the gamma aminobutyric acid (GABA) level. Albino Wistar rats were used as the experimental animals. Different neuropharmacological paradigms such as the motor co-ordination by the rotarod, pentobarbitone-induced sleeping time and the PTZ-induced convulsion were examined after administering deltamethrin orally at two doses, 150 mg/kg (LD₅₀) and 15 mg/kg (1/10 LD₅₀). The GABA level in the rat brain was estimated by HPLC after a single oral dose of 150mg/kg deltamethrin. Deltamethrin significantly reduced the motor coordination, decreased the onset time and increased the sleeping time duration induced by pentobarbitone. In addition, it also decreased the onset time and increased the duration of convulsions induced by PTZ at 150 mg/kg (LD₅₀) and 15 mg/kg (1/10 LD₅₀), respectively. Further deltamethrin administration decreased the GABA levels in the cerebellum as well as in the whole brain (except the cerebellum) significantly at the LD₅₀ dose level. There was some correlation between the effect of deltamethrin on the central GABA levels and its neuropharmacological effects.

Repeated dose toxicity of alfa-cypermethrin in rats

The present study was performed to investigate the subacute effect of alpha-cypermethrin (alpha-CP) in rats. Alfacypermethrin a synthetic pyrethroid insecticide, dissolved in dimethyl sulfoxide (DMSO) and oral LD50 was investigated after administering orally different doses in rats and was determined as 145 mg/kg. Other groups of rats were given repeated daily oral dose (1/10 LD50) of alpha-CP for 30 days. The animals were sacrificed on 31st day. Activities of various enzymes, cytochrome P450 and b5 contents in liver, hepatic antioxidant status, tissue residue concentration, haemogram and pathological changes were studied. It increased the serum aminotransaminases (AST, ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) activities and blood glucose level significantly. alpha-CP decreased RBC count, PCV and Hb level significantly. It significantly decreased cytochrome P450 in liver. Residues were present in different tissues. It increased malondialdehyde (MDA) level, while decreased the activities of catalase (CAT), superoxide dismutase (SOD) and glycogen level in liver significantly. Mild to moderate histological alterations were observed in lungs, liver, stomach, kidneys, testes and cerebellum. So repeated daily oral doses of alpha-CP at 1/10LD50 altered the biochemical parameters, decreased cytochrome P450 content, antioxidant status, which correlated with histopathological changes of tissues.

Development of biodegradable microcapsules as carrier for oral controlled delivery of amifostine

The primary objective of this project was to develop a biodegradable, orally active controlled-release formulation of amifostine. Development of such a formulation will mark an important advancement in the areas of chemoprotection and radioprotection. Biodegradable microcapsules of amifostine were prepared using poly(lactide/glycolide) (PLGA 50:50). The microcapsules were prepared by solvent evaporation technique. Amifostine-loaded microcapsules were evaluated for particle size, surface morphology, thermal characteristics, and drug release. Particle size and surface morphology were determined using scanning electron microscopy (SEM). Thermal characterization was conducted using differential scanning calorimetry (DSC). In vitro release study was performed at 37 degrees C using phosphate buffer (pH 7.4). Amifostine release was calculated by measuring the amount of drug remaining within the microcapsules at a specific sampling time. The amount of amifostine in the samples was determined by high-performance liquid chromatography (HPLC) using an electrochemical detector. The yield of microcapsules was 75%. Scanning electron microscopy pictures revealed that the particles were nearly spherical and smooth with an average size of 54 microm. Differential scanning calorimetry thermograms showed that microcapsules loaded with amifostine have a glass transition at 39.4 degrees C, and the melting endotherm of amifostine was absent. The absence of a melting endotherm for amifostine was an indication that amifostine was not in the crystalline state in the microcapsules, but rather in the form of a solid solution in PLGA. Approximately 50% amifostine was released during the first 6 hr of the in vitro release study. The drug, however, continued to release over the observed period of 12 hr during which 92% amifostine was released.

Effect of glycosylation on structure and dynamics of MHC class I glycoprotein: a molecular dynamics study

Complex carbohydrates linked to glycoproteins are recently being implicated to play a variety of biological roles. The lack of well-resolved crystallographic coordinates of the carbohydrates makes it difficult to assess the contributions of the glycan chain on protein structure and dynamics. We have modeled two different oligosaccharides NeuNAc2Gal3Man3GlcNAc5Fuc and Man3GlcNAc4 to generate two glycosylation variants of major histocompatibility complex (MHC) class I glycoprotein. Molecular dynamics simulations of the isolated fourteen- and seven-residue oligosaccharides have been done in vacuo and in solution. The dynamics of the two glycoforms of MHC class I protein have been simulated in solution in the free as well as in the peptide-bound form. Good agreement between the calculated solution conformations of the oligosaccharides in isolated and conjugated forms and the average conformations obtained from x-ray or NMR data was observed for most of the glycosidic linkages. These molecular dynamics simulations of the isolated glycan chains and the glycoconjugates reveal the details of the conformational flexibility of the glycan chains; they also provide atomic level details of protein-carbohydrate interactions and the effect of the ligand binding on the carbohydrate structure and dynamics. It was found that though there is some flexibility in some of the glycosidic linkages in the isolated oligosaccharides, in the protein-conjugated form the linkages adopt more restricted conformations. The glycan chains protrude out into the solvent and might hinder the lateral association of the proteins. The presence of the bulky glycan chains does not affect the average backbone fold of the protein but induces local changes in protein structure and dynamics. It has been noted that the extent of the changes depends upon the nature of the attached glycan chain. The glycan chains do not appear to influence the peptide binding property of the protein directly, but may stabilize the protein residues that are involved in ligand binding.

Porous biodegradable microparticles for delivery of pentamidine

The primary objective of this study was to develop a method for the preparation of porous biodegradable controlled release formulation of poly(lactide/glycolide) (PLGA). The model drug used for this study was pentamidine. Scanning electron microscopy pictures showed that these microparticles are highly porous and spherical in shape. A comparison of particle size reveals a similar median particle size (54-68 microm) in all six batches. The particles are all smaller than 90 microm. Differential scanning calorimetry thermograms revealed that pentamidine was mostly present in the crystalline form in the microparticles and did not dissolve in PLGA. The efficiency of encapsulation of pentamidine was higher than 58% in all six batches. The amount of drug released from these microparticles was at least 12% within the first 60 min. At least 50% of the total drug was released within the first 4 h. Drug release from these microparticles continued for up to 12 h. This faster drug dissolution was due to the highly porous surface. This highly porous surface will allow large molecules to release at a much faster rate than the regular microcapsules/microspheres.

Effect of peptide loading and surfactant concentration on the characteristics of physically crosslinked hydrogel

The purpose of this study was to investigate the effect of varying drug load and concentration of a surfactant (sodium lauryl sulfate [SLS]) on the release characteristics of a model peptide (bovine serum albumin [BSA]), and study the net effects of the swelling properties of the hydrogel matrix [poly(vinyl alcohol) (PVA)]. The PVA hydrogel was prepared by a freeze-thaw process in the absence of a chemical crosslinking agent. The effect of protein loading on drug release was examined at three levels (0.65, 1.3, and 2%), whereas the effect of SLS was studied at four levels (0, 0.07, 0.13, and 0.26%). The baseline time for reaching equilibrium swelling was 48 hr for the hydrogel containing 0.65% BSA, and the equilibrium swelling time decreased significantly as the protein load was increased to 2%. The net effect of increased BSA concentrations resulted in faster BSA dissolution from the hydrogel matrix. The equilibrium-swelling ratio decreased from 21 to 10% when SLS was added to the PVA solution, which resulted in a reduction in the extent of equilibrium swelling; however, the time to reach equilibrium swelling was increased. The investigation provided a mechanistic basis toward the development of a hydrogel formulation by altering the concentration of two fundamental components, i.e., drug and surfactant, within the delivery system.

Toxico-kinetics, recovery, and metabolism of napropamide in goats following a single high-dose oral administration

Toxicokinetic behavior, recovery and metabolism of napropamide (a pre-emergent herbicide) and its effect on Cytochrome P(450) of liver microsomal pellet were studied following a single high-dose oral administration of 2.5 g kg(-1) and continuous (7 days) oral administration of 500 mg kg(-1) in black Bengal goat. Napropamide was detected in blood at 15 min and the maximum quantity was recovered at 3 h after administration. The absorption rate constant (Ka) value was low indicating poor absorption from the gastrointestinal tract. High elimination half-life (t(1/2) beta) and low body clearance (Cl(B)) values coupled with higher transfer of compound from tissue to central compartment (K(21)) suggest that napropamide persisted in the blood for a long time, i.e., after 72 h of oral administration. The recovery percentage of napropamide, including metabolites, from goats varied from 75.94 to 80.08 and excretion of the parent compound through feces varied from 18.86 to 21.59%, indicating that a major portion of the orally administered napropamide was absorbed from the gastrointestinal tract of goat. Napropamide significantly increased the Cytochrome P(450) content of liver microsomal pellet. The recovery of metabolites from feces, urine, and tissues ranged from 4.2--6.2, 40.81--49.42, and 2.7--11.6%, respectively, during a 4--7 day period. The material balance of napropamide (including metabolites) following a single high-dose oral administration at 2.5 g kg(-1) during 4--7 days after dosing was found to be in the range of 75--80%.

Toxico-kinetics, recovery efficiency and microsomal changes following administration of deltamethrin to black Bengal goats

A study of the toxico-kinetics, recovery percentage from different substrates, cytotoxicity and role of cytochrome P450 and b5 of liver microsome in the metabolism of deltamethrin were carried out in female black Bengal goat. The ALD50 value of deltamethrin in goat by intravenous route lies between 0.2 and 0.6 mg kg-1. Intravenous disposition kinetics using a dose of 0.2 mg kg-1 showed that the maximum blood concentration of deltamethrin was recorded at 0.5 min, followed by rapid decline, and a minimum concentration was detected at 6 min after administration. The following values were obtained: Vdarea 0.148 (+/- 0.02) litre kg-1; t1/2 (alpha) 0.22 (+/- 0.02) min; t1/2 (beta) 2.17 (+/- 0.37) min; Kel 1.05 (+/- 0.24) min-1; AUC 4.30 (+/- 0.45) micrograms min ml-1; ClB 0.05 (+/- 0.006) litre kg-1 min-1; T-B 1.93 (+/- 0.58); fc 0.40 (+/- 0.05). After 10 min, liver retained the maximum residue, and heart, adrenal gland, kidney, spleen, fat and brain also held the insecticide; liver, fat, heart and spleen retained residue after 30 min, and bone, liver and fat retained residue after 60 min of intravenous administration. Oral absorption of deltamethrin was poor and inconsistent, and approximately 65% of administered dose was recovered from faeces and gastrointestinal contents. The excretion of deltamethrin through urine was meagre, and only 0.01 and 0.013% of the administered dose was recovered after 3 and 5 days of oral administration respectively. All the tissues retained the residue after 3 days; while fat, rumen, reticulum, omasum, abomasum, large and small intestine and bone retained the residue after 5 days of oral administration; and the percentage recoveries were 1.73 and 0.027 respectively. Deltamethrin reduced the level of cytochrome P450 content of liver microsomal pellet of goat after 5 days of oral administration. Histopathological examination of liver, kidney, heart, spleen brain and lung sections of treated goats did not reveal any pathological changes.

Molecular modelling of MHC class I carbohydrates

In this article we present the results of molecular modelling of four complex carbohydrates which have been found in the MHC class I proteins. Though these proteins show diversity in their sequences, the glycosylation sites are highly conserved indicating a possible structural/functional role of the glycan chain. Similar glycan chains have been found linked with other proteins of completely different function, such as IgG, and erythropoeitin. Thus, the molecular modelling of these carbohydrates will not only provide structural/dynamic information of these complex molecules but will also provide conformational information which can be utilised to build the glycoprotein models. The results presented here indicate that although several linkages show less conformational flexibility, terminal linkages can be quite flexible.

Swelling-controlled release system for the vaginal delivery of miconazole

Miconazole nitrate, a fungicidal, is effective for the local treatment of vaginitis. The objective of this project was to develop a swelling-controlled release delivery system for miconazole. An aqueous solution of 15% w/w poly(vinyl alcohol) was mixed with a specific amount of miconazole powder. The resultant mixture was cross-linked by freeze-thawing. The effect of the number of freeze-thawing cycles was studied at four levels. The effect of the presence of PEG was studied by mixing different concentrations of two different PEG. The swelling at the end of 48 h was significantly higher (32%) for the batch that underwent four cycles. The swelling within the first 15 min for the batches containing PEG1000 was approximately 9%. However, the swelling for the batches containing PEG1450, at much lower concentration, within the same period was between 10 and 19%. The drug release profiles up to 108 h were independent of the number of freeze-thawing cycles. The cumulative percent miconazole released, in the absence of PEG, (two, four, six, eight cycles) at the end of 108 h was between 30 and 35%. The drug release was lower for the batches containing PEG1000, irrespective of the concentrations, compared with the batches containing PEG1450. A comparison of the value of diffusional exponent (n) indicates the predominance of a Fickian diffusion mechanism of release from the hydrogels.

Study of quinalphos (an environmental oestrogenic insecticide) formulation (Ekalux 25 E.C.)-induced damage of the testicular tissues and antioxidant defence systems in Sprague-Dawley albino rats

The effect of quinalphos (O-O-diethyl-O-[quinoxalinyl-(2)-thionophosphate]), an environmental oestrogenic organophosphorus insecticide pollutant, was studied on Sprague-Dawley albino rats at doses of 250 and 500 microgram kg(-1) body wt. i.p. for 3, 8 and 15 days, respectively. After the treatment with quinalphos there was an increase in the lipid peroxides (as measured by manoldialdehyde production) and a decrease in the total lipid content for the testicular membrane. The effects were more pronounced at the low doses than at the higher doses, indicating that some physiological defence mechanisms were in operation at higher doses. The free-radical-scavenging enzymes (superoxide dismutase, catalase and glutathione peroxidase) showed significantly higher activity at high dose in comparison to their activities at low-dose treatment. Glutathione content was gradually reduced after quinalphos treatment, both in low and high doses. Histomorphohological studies showed that after the low-dose treatment shrinkage of the tubular diameter and testicular atrophy leading to degenerative changes in the germinal epithelium were observed. But at high dose, gradual recovery of various germ cell layers and significant expansion of seminiferous tubules of Sprague-Dawley rat testes were found; the latter is generally believed to be a useful index of testicular activity through the hypothalamo-hypophyseal-gonadal axis. The present study indicates that quinalphos caused damage and degeneration of the testicular tissues due to free-radical-mediated lipid peroxidation at low doses. We have also demonstrated that, in response to the damage, an endogenous antioxidant enzyme defence system became operative at the higher dose of treatment.