Browsing by Author "Rahman, Md. Matiar"

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Electrochemical Characterization Of Biologically Important Electroactive Metal Ligand Complexes With Multi-electron Transfer Reactio
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2014-07) Rahman, Md. Matiar; Motin, Prof. Dr. Md. Abdul
The redox behavior of Cu (II) only and Cu (II) with aspartic acid (Apa), L-phenl alanine (Phe), 3-nitrobenzene sulfnate (NBS) ; Zn(II) only and Zn(ll) with Apa, Phe, NBS and Catechol ((ate) has been studied Cyclic voltammetry (CV), Differential pulse voltammetry (DPV) and Chronamperometry (CA) techniques. The voltammetri technique demonstrates the interaction of biologically important metals (Cu, Zn) with the ligands (Apa, Phe, NBS, Cate) that is formed of metal-ligand complexes. The interaction studies have been carried out in variation of metal ion concentration, ligand concentration, Buffer solution of different pH and scan rate. In all the studies of Cu(II) and Zn(II) complexes, with some exception, Cu(II )-ligand systems and Zn(II)-ligand systems have been found to undergo quasireversible electrode reaction with EC mechanism. For all the ligands, Apa and Phe are electroinactive ligands whereas Cate and NBS are electroactive ligands. Both the anodic and cathodic voltamnietric peaks were shifted and sometimes developed new peaks with the addition of Apa, Phe, NBS, Cate in Cu(II) and Zn(II) solutions. On the addition of Apa, Phe and NBS in Cu(II) solution, the peak positions of the voltammogram of Cu(II)-Apa, Cu(II)-Phe and Cu(II)-NBS, first anodic peak was shifted positively but the second oxidation peak was shifted negatively with respect to that of only Cu ( II). The peak current decreases significantly compared with that for free Cu(II) in the same experimental conditions, This behavior confirms the interaction and complexation between Cu(II) and Apa, Phe. The effect of pH of Cu(II)-Apa, Cu(II)-Phe and Cu(II)-NBS were studied by varying pH from 3.5 to 7.0. The peak current of Cu(II)-Apa, Cu (II)-Phe and Cu(II)-NBS increases with the decrease of pH indicating that at lower pH the Cu(II)-Apa, Cu(II)-Phe and Cu(II)-NBS is highly electroactive. The maximum peak current was obtained at pH 3.5. This shows that the electrochemical oxidation of Cu(II)-Apa, Cu(II)-Phe and Cu(II)-NBS is aicilitated in acid media and hence the rate of electron transfer is faster.The average diffusion coefficient, D of Cu(II)- Apa or Cu(II)-Phe is found to he 4.5 x l0-6cm2s-1. The cyclic voltammogram of Zn(II) only and Zn(II) with Apa, Phe, NBS and Cate in aqueous and in buffer solution of different pH were taken at different scan rates. The CV of Zn (II) shows at pH (1 .5, 3 and 4.5) one well defined anodic and cathodic peak at different scan rate hut in aqueous solution only Zn(II) showed very weak anodic peak. Upon the addition of Apa, Phe, NBS, Cate with Zn(II) the first anodic peak shifted positively and the cathodic peak is shifted negatively which indicates the formation of Zn (II)-Apa or Zn ( II)- Phe complex. The intensity of the anodic and cathodic peak current decreases with the increasing of Apa or Phe or NBS or Cate suggesting that is formed of more Zn( 11 )-Apa or Zn(II)- Phe or n(ll)- NBS complex. The effect of pH of Zn(II)-Apa, Zn(II)-Phe, Zn(II)-N BS and Zn(II)-Cate were studied by varying pH from 1.5 to 11. The peak current decreases with the increase of pH .The maximum peak current was obtained at pH 3-4.5.At higher pH(7-11), the anodic peak disappeared. This shos that the electrochemical oxidation of Zn(II) complexes is hindered in basic media. For the comparison CV of Zn(II) only and Zn( II) —Asp, Zn(II)-Phe, Zn( II)- Cate, Zn( II)-NBS at similar condition (pH 3, scan rate 0.1 V/s). it is seen that the anodic peak current of Zn(II)-Asp and Zn(II)-Phe are lower than that of Zn(II) only hereas the anodic peak current of Zn(II) - Cate and Zn(II)-NBS is higher than that of Zn(II) only. When Cate and NBS are coordinated with Zn(II) both metal and ligands are electroactive, So constructive interference of peak appeared whereas Asp and Phe are coordinated with Zn(II), here ligands are eleciroinactive so the overall peak currents are lower than Zn(II) only. The slopes of the plots of Ep against pH of all studied metal ligand complexes ere determined graphically as anodic peak 25- 35 mV/pH at 0.1 V/s, which is close to the theoretical value of 30 mV for a two-electron, two-proton transfer process which indicates that the oxidation of all metal-ligand complexes proceeded via the 2e-2H+ processes. This suggests that during the reaction not only electron but also protons are released from the metal-ligand complexes. For all the studied system, with the increasing of metal: ligand composition from 1:1 to 1:5 (metal fixed), the current decreases linearly but after more addition of ligands, the current intensity change is constant. This indicates that the availability of metal is limited for the formation of the metal-ligand complex at saturation point. When the composition of metal increases with the fixed of the composition of ligands from 1:1 to 5:1. after certain concentration, the voltammogram pattern reflected into the only metal, because of the deficiency, of ligands in solution. The relation between metal - ligand concentration and cyclic voltammetric anodic and cathodic peak current (Ipaand Ipc) is linear. The proportionality of the anodic and cathodic peak currents with square root of scan rate of all the studied metal ligand complexes with few exceptions suggests that the peak current of the difièrent complexes at each redox reaction is controlled by diffusion process. From the studied of all systems it is seen that current functions (1/v-1/2) decreased with the increasing of' scan rate except Zn(II)- Cate. So the behavior of electrode reaction of all Cu(II)- ligands and Zn(II)- ligands are of ECE mechanism except Zn(II)- Cate is of CE mechanism.
Ethnobotanical Study of Some Selected Plants Used in the Treatment of Skin and Diabetic Diseases in Bangladesh
(University of Rajshahi, 2020) Sadat, A F M Nazmus; Azad, Md. Abul Kalam; Rahman, Md. Matiar
This study investigated the indigenous people’s belief on some medicinal plants those commercially used to cure different types of skin diseases as well as diabetic diseases in Bangladesh. It was observed that around 400 to 1000 medicinal plants available in Bangladesh listed in different database. In the present study ten potential medicinal plants were selected based on their skin diseases curing ability and the anti-diabetic properties through ethnobotanical study. Around 176 peer reviewed publications connected to 24 major tribes’ lives in Bangladesh were studied during selection of plants. Ultimately fresh leaves of Neem (Azadirachta indica), Babla (Acacia nilotica), Pathorkuchi (Bryophyllum pinnatum), Sojna (Moringa oleifera) and Asham lota (Mikania cordata); fresh stems of Shornolota (Cuscuta reflexa); dried leaves of Papaya (Carica papaya) and Telakochu (Coccinia grandis); dried seeds of Ajawin (Carum copticum) and finally Kalo Jera (Nigella sativa) were enrolled in the present study. The pharmacological actions of these selected plants were assessed scientifically under a controlled laboratory setup. A comparatively noble and green extraction procedure named “Aqueous Ultrasound Assisted Extraction Method” was used for the preparation of crude extract which provided significantly high yield percentages. More than 30% yield was observed from the dried plant’s parts of N. sativa, C. grandis and C. papaya through this extraction procedure. Around 15% extraction was observed from fresh leaves of A. nilotica, A. indica and C. reflexa, however, still higher than the expected (10%) yield. Promising extraction also found from M. oleifera (17.42%), M. cordata (18%), C. copticum (19.14%) and B. pinnatum (21.59%). Most of the crude extracts were found acidic in nature except C. papaya and C. grandis. It was observed that M. cordata and C. copticum added more basic compounds during the extraction procedure observed by the pH changes of the solution before and after ultrasound treatment. Drastic pH changes were observed after ultrasound treatment on the plant material and indicated the nature of compound extracted from the plant parts. Crude extracts were dried by conventional water bath at 550C and preserved in a glass vial under freezing condition for further use. Crude extracts were undergone different phytochemical and pharmacological studies. Gram positive bacteria S. aureus, S. pyogenes and gram negative bacteria E. coli as well as fungi C. lunata, F. chlamydosporum and M. furfur were enrolled in the present study having distinct association on different types of skin diseases. Seven more pathogenic bacteria and 2 fungi were also included in the presents study for comparison of the antimicrobial activities. Antimicrobial activities were conducted by disc diffusion method and found promising antimicrobial activity of Azadirachta indica (against S. aureus), Acacia nilotica (against S. pyogenes and S. aureus), Bryophyllum pinnatum (against S. pyogenes, S. aureus and E. coli), Cuscuta reflexa (against S. aureus and S. pyogenes) and Moringa oleifera (against S. pyogenes). Comparatively poor sensitivity was observed against three enlisted fungi. These plants may be considered potential antimicrobial agents and may be suitable for curing different types of microorganism infected skin diseases. Three types of hypoglycemic studies were conducted to observe the anti-diabetic properties of the plants. Most of the enrolled plants were showed distinct properties on lowering blood glucose level of the dexamethasone induced diabetic mice. However extracts of A. indica, B. pinnatum, C. reflexa, C. papaya and C. grandis were showed very promising anti-diabetic effect almost similar to the standard anti-diabetic drug glibenclamide. From cytotoxic study all crude extracts were proved safer than the standard drug erythromycin and tetracycline. A purification stages were also performed by using a basic partition theory, and was observed that sufficient purifications were performed which may be considered for large scale purification including industrial setup. The whole study was conducted by minimum impact on the environment. From this study we justified the use of some ethnobotanicals for the treatment of different types of pathogenic skin diseases and diabetic disease.
Risk Factors of Hospital Acquired Infections among Patients Admitted in A Selected Hospital in Dhaka
(University of Rajshahi, 2016) Chowdhury, Md. Al Jahidi Hasan; Rahman, Md. Matiar
This prospective cross sectional observational and analytical study was conducted at UnitedHospital Ltd. Gulshan, Dhaka at all age and sex during January to July, 2015 with a view to findout the incidence of Hospital Acquired Infection (HAI), patient related risk factors, hospitalrelated risk factor, offending organism caused for HAI and their antimicrobial sensitivity. Out oftotal 1108 respondents, 104 (9.4%) respondents were found to develop HAI which yieldedincidence rate 8.75/1000 hospital days. Respiratory tract infection was the highest 56.7% among the types of HAI followed by urinary tract infection (15.4%). Not any single factor of socio demographic characteristics was found associated with the development of HAI.168 (16.7%) respondents of extreme of age group developed infection comparison to around 940(8.1%) of not of extreme of age develop infection and the association was found statisticallysignificant (p<0.001). An individual who required nursing assistance most of the time had 20 times more risk ofdeveloping HAI and those who required some assistance had 6.78times more risk than those whorequired no assistance. The Odds ratio (OR) for 3 functional categories were: 0.3, 0.9 and 6.1.60% HAI had >3 visitors followed by 39.6% were 3 visitors while 2.1%, 2.9% visited by 1 & 2visitor respectively. For the development of HAI, visitors were found statistically markedly significant (p<0.001). An individual who was visited by more than three visitors had around 118times more risk of developing HAI of respondents than who had no or one visitor. The Odds ratiofor 4 visitor categories were: 0.2, 0.2, 9.4 and 23.6. 96 (11.9%) with antibiotic therapy during hospitalization showed HAI while 8(2.6%) found HAI with no antibiotic (p<0.001). Regarding application of antimicrobial use up to 5 days, 16respondents (5.7%), 28 (7.6%) of 6-10 days, 32 (28.1%) of 11-15 days, 10 (45.5%) of 16-20 daysand 14 (70.0%) of duration more than 20 days developed infection. The association of duration ofantimicrobial use and development of HAI was found statistically highly significant (t=9.675,p=0.000). Around 24% respondents with underlying illness developed HAI in comparison 6.5% respondents without illness and the association was found statistically highly significant (p<0.001). 20.8% respondents with invasive device application developed HAI compare to 2.8%without device and statistically highly significant (p=0.000). 3.3% of respondents developed HAIwho had the application of invasive device up to 5 days, while 21.8% by 6-10 days, 38.9% by 11-15 days, 21.4% by 16-20 days and 50% by more than 20 days. The association of developing HAI with duration of use of invasive device was statistically highly significant (t=12.063,p=0.000).31.8% respondents having immunosuppressive therapy developed HAI on the contrary to7.5%without such therapy which showed association statistically highly significant (p<0.001).24.5% (80) respondents representing immunosuppressive condition developed HAI where 3.1% (24) had infection did not present such condition and association was found statistically highlysignificant (p=0.000). The mean hospital days for development of HAI group was 19.96±13.11 whereas hospital dayson discharge without infection group was 9.77±7.13. The association between hospital days anddevelopment of infection was found statistically highly significant (t=7.845, P=0.000). Routine operation 47 (20.2%) and emergency 19 (26.8%) respondents having HAI established nostatistically significant (p>0.05). On the other hand respondents having post operative showed HAI, 55(18.1%) and non-operative 49 (6.1%) infection. The association found statistically significant (p<0.001). 16 (14.5%) respondents found frequent transfer developed HAI comparison to 88 (8.8%) without transfer and association was statistically not significant (p>0.05). Regarding general cleanliness of ward/department, 9% had HAI satisfactory group contrary to 10.4% HAI from dirty group of respondents. No statistically significant association was found (p>0.05). The Logistic regression predicting independent risk factors revealed functional state (OR=22.067, p=0.001), number of visitor/patients/day (OR=71.000, p=0.000), underlying illness (OR=4.602, p=0.000), duration of device use (OR=19.000, p=0.011 and duration of antimicrobial use (OR=1.079, p=0.001) were found as independent risk for developing HAI. Gram negative Enterobacteriaceae as a group were most predominant pathogens. The highest infective agents were 33% HAI from Klebsiella pneumoniae followed by 17% Acinetobacter baumannii and both Esch.coli and Pseudomonas aeruginosa each 14%.Only colistin sulphate was reported sensitivity range from 76 to 100% while almost all other isolates were observed multi drug resistance (MDR). Measured aimed at increasing awareness of hospital staff, a large scale study, formulation of antibiotic policy, controlling of visitors, appropriate device handling procedure, establishing a strong surveillance programme through infection control and prevention department for minimize or control hospital acquired infection. Epidemiological studies are strongly recommended in order to detect source of infection.