Substituent effect on spectral and antimicrobial activity of Schiff bases derived from aminobenzoic acids


The dependence of electronic absorption spectra antimicrobial property on the substituent position was investigated using three Schiff bases derived from salicylaldehyde and isomeric aminobenzoic acids in three solvents of different polarities. The absorption maxima in all three solvents exhibited dependence on the position of substituent with the absorption maxima undergoing a red shift as solvent polarity increased. The in vitro antibacterial activity of the compounds against some clinically important bacteria namely Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), Enterococcus feacalis (ATCC 29212) was determined in N,N”-dimethylformamide and 1,4-dioxane using the agar dilution method. The results revealed that the ortho and meta substituted Schiff bases exhibited better antimicrobial activity in the non-polar solvent.

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Ejiah, F. , Fasina, T. , Familoni, O. and Ogunsola, F. (2013) Substituent effect on spectral and antimicrobial activity of Schiff bases derived from aminobenzoic acids. Advances in Biological Chemistry, 3, 475-479. doi: 10.4236/abc.2013.35051.


The prevalence of idiopathic hypercalciuria (IH) has been reported to vary between 2.9% - 6.2% in the age group of 3 months to 18 years [1-6]. The majority of these cases are asymptomatic. Symptomatic cases have various manifestations such as gross hematuria, dysuria, nocturnal enuresis, urinary frequency—urgency syndrome, supra-pubic and abdominal pain and recurrent urinary tract infections [7]. It predisposes to nephrolithiasis that may cause renal damage. These complications are avoidable if appropriate preventive measures are undertaken by early detection of IH. It is done by measurement of urinary calcium excretion, but it is difficult to take the accurate 24 hours urine in young and non-toilet trained children. Therefore, hypercalcuria can be screened by random urine Ca/Cr ratio [8-10] preferably fasting. It is incumbent on a laboratory to report urinary Ca/Cr ratio, and a reference interval must be required above which a result is considered abnormal, but these cut-offs are not firmly established because of difficulties of generating reference intervals for children particularly across the span of ages in childhood [11]. Reference values for urine calcium/ creatinine ratio in normal infant and children have been reported by several authors worldwide, but these data are controversial, possibly due to the differences between study populations, genetic characteristics and the variations in dietary intake of calcium, sodium and protein in different geographic regions [1-4,9, 10,12-15]. So the objective of the present study was to determine urine Ca/Cr ratio in healthy infant and children in Burdwan district, West Bengal.


2.1. Selection of Subjects

A total of 693 normal infant and children aged 3 months to 18 years from three public schools and a well-baby clinic of Burdwan district were selected by simple random sampling after informed consent had been received from the parents between March 2011 and May 2013. Among them three hundred twenty (53.82%) were boys and 195 (46.18%) were girls All of them had normal physical growth and blood pressure. They were told not to change their eating habits and physical activities. Children with conditions that would influence urinary calcium excretion such as being on medical treatment or suffering from malnutrition, chronic disease such as kidney diseases, metabolic disorders were excluded. Then the study population was divided into five groups according to their age: Group I: <1 year, Group II: 1 -< 2 years, Group III: 2 -< 5 years, Group IV: 5 -< 10 years and Group V: 10 - 18 years.

2.2. Collection of Samples

Early morning non-fasting urine sample were collected from the study population to determine calcium and creatinine levels. After collection all the tests were done immediately.

2.3. Parameters Assay

Urinary calcium was estimated by 2-cresolphthalein complexone method [16] using semi auto analyser (Chem 5v2 plus). Intra assay CV% was 1.5 and inter assay CV was 2.7 for this method. Urinary creatinine concentration was assayed by modified Jaffes’ method [17] using (Chem 5v2 plus) semiautoanalyser. Intra-assay CV% was 1.8 and inter-assay CV% was 2.9. Then urinary Ca/Cr (mg/mg) ratio was calculated.

2.4. Statistical Analysis

The data for biochemical analysis was subjected to standard statistical analysis using the Statistical Package for Social Science (SPSS) 11.5 software for windows.


In Burdwan district the distribution of urinary Ca/Cr ratio in the paediatric study population is depicted in Figure 1.

Table 1 showed the mean, standard deviation and percentile values of different age group. It was found that there was decrease in urinary Ca/Cr ratio as age of the study population increased and this ratio significantly negative correlate (Pearson Correlation −0.217) with increasing age (p < 0.01) analysed by Pearson correlation. It was also seen that different percentile values of each age group also decreased according to increased age.

Although urinary Ca/Cr ratio and its 97.5th percentile value were more in girls, the different did not show significant difference (p > 0.01) as shown in the Table 2.

Figure 2 shows the comparison between the percentile values of different age groups and it is shown that there was definite decrease in percentile values according to increasing of age.

Conflicts of Interest

The authors declare no conflicts of interest.


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