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Articles by A. Chowdhury
Total Records ( 11 ) for A. Chowdhury
  S.K. Biswas , A. Chowdhury , J. Das , A. Chowdhury , S.Z. Raihan and M.A. Muhit
  The present study was designed to detect the presence of phytochemical compounds and to evaluate the cytotoxic profiles and antibacterial activities of the ethanol extract of the leaves of Elaeocarpus serratus. The phytochemical investigation was done according to the standard procedures. The phytochemical analysis of the extract showed the presence of alkaloid, glycoside, tannin, saponin, flavonoid and carbohydrate. The antibacterial tests of the plant extract and the standard drug, Levofloxacin were conducted against eight bacterial strains using agar disc diffusion technique. The extract at 500 μg disc-1 produced significant zone of inhibition against Bacillus subtilis (25.82±0.61mm), Bacillus megaterium (30.52±0.43 mm), Pseudomonas aeruginosa (20.35±0.51), Salmonella typhi (32.95±0.39 mm) and Vibrio cholerae (16.93±0.14) but no zone of inhibition was detected against Staphylococcus aureus, Escherichia coli and Shigella dysenteriae. The obtained results were also compared with the standard drug, Levofloxacin used at the concentration of 10 μg disc-1. Subsequently, the cytotoxicity test of the plant sample was performed using brine shrimp lethality bioassay which showed lethality against the brine shrimp nauplii with LC50 141.25 and LC90 870.96 μg mL-1. Finally, it was concluded that the ethanol extract of the leaves of Elaeocarpus serratus possessed significant antibacterial and cytotoxic properties.
  S.K. Biswas , A. Chowdhury , S.Z. Raihan , M.A. Muhit , M.A. Akbar and R. Mowla
  Kalanchoe pinnata is used in traditional medicines for the treatment of several health problems in Bangladesh. The study was designed to investigate the cytotoxicity and antibacterial activities of the chloroform extract of the leaves of Kalanchoe pinnata. Qualitative phytochemical analysis was also performed for the identification of several phytochemical compounds such as alkaloids, glycosides, steroids, gums, flavonoids, saponins, reducing sugar, tannins and terpenoids. The study revealed that the plant extract contained all of the phytoconstituents except steroids, flavonoids and terpenoids. The agar disc diffusion technique was used to investigate the antibacterial activities of the plant extract at 500 μg disc-1 against eight bacterial strains. The plant extract showed very low antibacterial activities with zone of inhibition ranging from 0.33±0.02 to 1.67±0.02 mm, while the maximum antibacterial action was recorded against E. coli with zone of inhibition of 1.67±0.02 mm but no sensitivity was found against V. cholerae. The antibacterial activity of the plant extract was compared with the standard drug, Levofloxacin which was used at 10 μg disc-1. Brine shrimp lethality bioassay was also done to find out the cytotoxic activity of the plant sample. The chloroform extract of the plant showed lethality against the brine shrimp nauplii (LC50: 125.89 and LC90: 234.42 μg mL-1. Finally, it was concluded that the chloroform extract of the plant leaves possessed considerable cytotoxic activity with less antibacterial potentials.
  R. Pal , K. Chakrabarti , A. Chakraborty and A. Chowdhury
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  R. Pal , K. Chakrabarti , A. Chakraborty and A. Chowdhury
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  U.K. Karmakar , S.K. Biswas , A. Chowdhury , S.Z. Raihan , M.A. Akbar , M.A. Muhit and R. Mowla
  The ethanol extract of Asparagus racemosus Willd was examined for antbacterial and antioxidant properties. Phytochemical investigation was also done to identify the presence of phytochemical compounds. The ethanol extract at the concentration of 500 μg disc-1 showed moderate antibacterial activity against Staphylococcus saprophyticus, Enterococcus faecalies, Streptococcus agalactiae and Escherichia coli with zone of inhibition of 7.77±0.37, 6.07±0.06, 10.10±0.11 and 6.00±0.04 mm, respectively while 250 μg disc-1 of the extract did not reveal any zone of inhibition against the tested bacterial strains. Antioxidant activity of the ethanol extract was determined according to their scavenging activity of the stable DPPH (1,1-diphenyl-2-picryl hydrazyl) free radical and 10% H2SO4. In the qualitative antioxidant assay, the extract showed free radical scavenging properties. Preliminary phytochemical analysis of the plant extract showed the presence of alkaloids, tannins, saponins, glycosides, flavonoids and carbohydrates which could be responsible for antibacterial and antioxidant properties justifying the ethnomedicinal applications of Asparagus racemosus. Thus, further advanced research is necessary to isolate and characterize the chemical compounds responsible for the therapeutic activities of the plant.
  S.K. Biswas , A. Chowdhury , J. Das , U.K. Karmakar , S.Z. Raihan , A.C. Das , M.A. Hannan , M.A. Monsur Dinar , M.J. Hassan , M.I. Hossain and M.R. Farhad
  Cuscuta epithymum Murr. (Convolvulaceae) is found in Bangladesh and has been used in traditional medicine. The present study was designed to investigate the preliminary phytochemical screening, cytotoxicity and antibacterial activities of the methanol extract of the plant stem. The preliminary phytochemical analysis was performed on the basis of the standard procedures and thin layer chromatography to confirm the presence of chemical compounds in the methanol extract of the plant. The minimum inhibitory concentration and cytotoxic activities of the extract were carried out according to broth dilution assay and brine shrimp lethality bioassay, respectively. The results of preliminary phytochemical analysis showed the presence of flavonoid, glycoside, alkaloids, carbohydrates, saponins and steroids in the plant extract. In this study, the methanol extract was subjected to Thin Layer Chromatography (TLC) in order to detect the phytoconstituents present in the extract and the best result of TLC was obtained from the solvent system comprising of toluene and ethyl acetate at the ratio of 5.5:4.5 which identified the maximum number of spots. Moreover, the extract showed moderate antibacterial activities against Bacillus megaterium, Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi with MIC values of 4.96±0.20, 3.03±0.16, 3.47±0.20 and 4.07±0.08 mg mL-1, respectively. The methanol extract showed lethality against brine shrimp nauplii (LC50: 36.31 μg mL-1 and LC90: 83.18 μg mL-1 ). The results indicated that the methanol extract of the stem of the plant possessed antibacterial and cytotoxic properties with several numbers of chemical compounds.
  U.K. Karmakar , S.K. Sadhu , S.K. Biswas , A. Chowdhury , M.C. Shill and J. Das
  In ayurveda, Asparagus racemosus Willd is known as the queen of herbs because it has a strong rejuvenating, nurturing and stabilizing effect on excessive air, gas, dryness and agitation in the body and mind. Ethanol extracts of Asparagus racemosus (EEAR) belonging to the family Liliaceae was investigated for biological action. The present study was designed to evaluate the cytotoxicity, analgesic and antidiarrhoeal properties of the ethanol extract of whole plant of Asparagus racemosus. The test for analgesic activity of the crude ethanol extract was performed using acetic acid induced writhing model in mice. On the other hand, antidiarrhoeal test of the EEAR was done according to the model of castor oil induced diarrhoea in mice and brine shrimp lethality bioassay was used to determine the cytotoxic activity of ethanol extract of the plant. In acetic acid induced writhing in mice, the ethanol extract exhibited significant inhibition of writhing reflex 67.47% (p<0.01) at the dose of 500 mg kg-1 body weight. The plant extract showed antidiarrhoeal activity in castor oil induced diarrhoea in mice. It increased mean latent period and decreased the frequency of defecation with number of stool count at the dose of 250 and 500 mg kg-1 body weight, respectively comparable to the standard drug Loperamide at the dose of 50 mg kg-1 body weight. In addition to these, the brine shrimp lethality test showed the significant cytotoxic activity of the plant extract (LC50: 10 μg mL-1 and LC90: 47.86 μg mL-1). The obtained results support the traditional uses of the plant and require further investigation to identify the chemical constituent(s) responsible for cytotoxicity, analgesic and antidiarrhoeal activities.
  S.Z. Raihan , M.M. Monir , P. Biswas , S.K. Biswas , A. Chowdhury , J. Das and A.C. Das
  Dalbergia spinosa Roxb. (Family: Fabaceae) has many traditional uses in Bangladesh. The crude methanol extract of the stem barks of D. spinosa Roxb. was investigated for possible antinociceptive activity using acetic acid induced writhing model in mice. Phytochemical analysis was also performed using standard procedures to detect the presence of phytochemicals in the crude plant extract. The study results showed 37.20% inhibition of writhings in the tested mice when methanol extracts were given intraperitoneally (i.p.) at the dose of 250 mg extract kg-1 b.wt. The maximum inhibition (40.01%) of nociception effect was achieved at 500 mg extract kg-1 b.wt., i.p. which was also compared with the antinociceptive activity of the standard drug, diclofenac sodium at the dose of 25 mg extract kg-1 b.wt. which produced 68.37% inhibition of nociception effect. The inhibition of writhings was calculated in respective to control group and it was found that p-values (<0.0001) calculated by student’s t-test were statistically significant. However, the phytochemical screening revealed the presence of alkaloid, steroid, flavonoid, tannin, reducing sugar and gum. Finally, it can be concluded that crude methanol extracts of D. spinosa stem barks contain biologically active phytoconstituents exhibiting significant dose-dependent antinociceptive activity in the mice model used. Thus, it is recommended to isolate and characterize the compounds for the development of new analgesics.
  A. Chowdhury , Tushar Kanti Bera , D. Ghoshal and B. Chakraborty
  In this study, electrode contact impedances and their effects on the measurement have been studied in a fruit impedance measurement system using Electrical Impedance Spectroscopy (EIS). The EIS study has been conducted on the banana samples during their ripening and the variation of contact impedance with frequency at different ripening state has been observed. The contact impedance under each electrode has been calculated by using compound electrodes developed from stainless steel sheets and the effect of the contact impedance on the measurement accuracy has been studied. The total contact impedance has been computed by comparing electrical impedance of banana obtained with two terminal and four terminal method using the compound electrodes consisting of current and voltage electrodes concentrically placed on banana surface. It is found that banana impedance obtained with two terminal method is higher in magnitude than the four terminal method with compound electrodes. It is also found that the contact impedance under each electrode is maximum at low frequency and minimum at high frequency.
  J. Das , S.K. Biswas , A. Chowdhury , S.R. Sharif and M.A. Hannan
  The petroleum ether extract of stem barks of Moringa oleifera Lam. was evaluated for antibacterial and antifungal activities. Ten bacterial strains were used in the study for antibacterial activities while six species of fungi were also bioassayed for their response to the extract. Agar disc diffusion method was used for antibacterial and antifungal assay of the petroleum ether extract at 500 μg disc-1. The results were also compared with the standard drugs, amoxicillin (10 μg disc-1) and griseofulvin (10 μg disc-1). The obtained results showed inactivity of the petroleum ether extract to all of the tested bacterial and fungal strains.
  S.K. Biswas , S. Paul , A. Chowdhury and J. Das
  Gastroretentive floating pellets of metronidazole were formulated to prolong the gastric residence time in order to obtain controlled release characteristics of the drug. Nine formulations of metronidazole floating pellets such as AX, BX, CX, AY, BY, CY, AZ, BZ and CZ were prepared by extrusion method using different quantities of hydroxyl propyl methyl cellulose (HPMC) polymers such as methocel K4M premium and methocel K100LV premium in the ratio of 2:1, 1:2 and 1.5:1.5 while the amount of Na-alginate used in the formulations was 3.50, 5.25 and 7.0 g, respectively. The in vitro dissolution studies were carried out in 900 mL of phosphate buffer (pH 1.2) at 37±0.5°C and 50 rpm for 6 h using USP XXIV paddle method and the content of drug release was done by UV spectrophotometer at 277 nm. It was found that the percent release of metronidazole from different formulations was different with passing of time. The drug release profile of the formulation (AX) having Na-alginate 3.50 g methocel K4M premium and methocel K100LV premium in the ratio of 2:1 showed best fit to Higuchi release kinetics with R2 value of 0.994. Finally, it might be concluded that the polymers had significant effect on drug release kinetics of metronidazole from floating pellets. The selection and use of suitable polymers in appropriate ratio might be very important in designing floating pellets and using the capabilities of these polymers, suitable floating pellets of metronidazole with desirable release rate could be formulated. Thus, in vivo research studies by the future researchers will confirm the appropriateness of these formulated metronidazole floating pellets.
 
 
 
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