ANTIBACTERIAL ACTIVITY OF THE LEAF EXTRACTS OF ALCHORNEA CORDIFOLIA (Euphorbiaceae) AGAINST ISOLATES FROM PATIENTS WITH RESPIRATORY TRACT INFECTION IN AHMADU BELLO UNIVERSITY TEACHING HOSPITAL ZARIA, NIGERIA

ANTIBACTERIAL ACTIVITY OF THE LEAF EXTRACTS OF ALCHORNEA CORDIFOLIA (Euphorbiaceae) AGAINST ISOLATES FROM PATIENTS WITH RESPIRATORY TRACT INFECTION IN AHMADU BELLO UNIVERSITY TEACHING HOSPITAL ZARIA, NIGERIA

Abstract:

Many bacterial species have been reported to develop resistance to antibiotics commonly prescribed for respiratory tract infections. Therefore, the need to search for natural products for remedy of this problem cannot be overemphasized. One hundred and eighty (180) specimens were collected from throat (68) and ear swabs (57) as well as sputum (55) from patients with respiratory tract infection in Ahmadu Bello University Teaching Hospital Zaria, Nigeria. Isolation and identification of the bacterial isolates were carried out using standard microbiological methods. MicroGen identification kit was used for confirmatory identification of the isolates. The ethanol and aqueous extracts of Alchornea cordifolia was carried out using cold maceration extraction method. Agar well diffusion, agar dilution and spread plate methods were employed to determine the zone of inhibition, minimum inhibitory concentration, minimum bactericidal concentration and rate of kill respectively.The aqueous extracts was fractionated using column chromatography. Thin layer Chromatography method was used to identify the phytochemical constituents of the active fraction F2. The bacterial isolates identified were Staphylococcus aureus (7), Pseudomonas aeruginosa (2), Klebsiella pneumoniae (2), Escherichia coli (1) and Streptococcus spps (5). The two extracts showed broad spectrum of activity but the aqueous extract had larger zones of inhibition ranging from 32. 5 mm – 11. 5 mm and lower M.I.C and M.B.C values ranging from 5 mg/ml – 20 mg/ml. The fractionation of the aqueous extract gave thirty five (35) fractions but after pooling together of similar ones, Seven (7) different fractions were obtained. The M.I.C of the fractions showed that F2 had the lowest M.I.C values against all the isolates and better antibacterial activity. The F2 fraction had M.I.C values that ranged between 2.5 – 5 mg/ml against S. aureus and 5 – 10 mg/ml against Strep. spp. The death/survival rate showed that at 1440 minutes, M.I.C concentration of 2.5 mg/ml of F2 had 100 % kill; there was reduction in surviving cells with both the Sub-M.I.C concentration of 1.25 mg/ml and amoxicillin clavulanic acid 30 μg/ml against S. aureus (T38) isolate. A total kill was observed at 240 minutes, with M.I.C concentration of 5 mg/ml and at 1440 minutes, with Sub-M.I.C concentration of 2.5 mg/ml against Klebsiella pneumoniae (S16). There was a decrease in the number of surviving cells in the positive control and increase in the number of surviving cells with time in the negative control. The TLC based phytochemical screening of F2 fraction revealed the presence of phenolic compound and flavonoid as secondary metabolites. This study has justified the traditional use of Alchornea cordifolia leaf extracts in the treatment of respiratory tract infection caused by bacteria.

ANTIBACTERIAL ACTIVITY OF THE LEAF EXTRACTS OF ALCHORNEA CORDIFOLIA (Euphorbiaceae) AGAINST ISOLATES FROM PATIENTS WITH RESPIRATORY TRACT INFECTION IN AHMADU BELLO UNIVERSITY TEACHING HOSPITAL ZARIA, NIGERIA