Phytochemical and Antibacterial Screening of Andrographis paniculata (King of Bitterness) Leaf Extracts on Bacteria Isolated from the Foot Ulcers of Diabetic Patients

Foot ulcers are common among diabetic patients and can lead to severe bacterial infections. The aim of the study was to determine the antibacterial activity of Andrographis paniculata leaf extracts on clinical pathogens isolated from foot ulcers of diabetic patients. A total of 5 typed strains comprising of Acinetobacter johnsonii strain JUQ303, Pseudomonas rhodesiae strain YHBT5, Alcaligenes faecalis strain 2, Alcaligenes faecalis strain N148 and Alcaligene faecalis strain 3 were isolated from patients attending clinics at the National Orthopedic Hospital, Enugu. The leaves of Andrographis paniculata were obtained from a local garden in Anaocha, a local government area in Anambra state. The leaves of Andrographis paniculata were pulverized and extracted using ethanol, acetone and aqueous solvents. Preliminary qualitative and quantitative phytochemical analyses of the leaf extracts were done using standard methods to reveal the presence of the concentrations of basic phytocomponents. The ethanol, acetone and aqueous crude extracts of the leaves of Andrographis paniculata were reconstituted using 5ml of Dimethyl sulfoxide (DMSO) to obtain concentrations of 200, 100, 50, 25, 12.5, 6.25, 3.125 and1.56mg/ml. The isolates were screened for sensitivity to the plant extracts using the agar well diffusion method. The minimum inhibitory concentration was determined by the agar well diffusion method. The antibiotic susceptibility pattern of the isolates was analyzed using the Kirby-Bauer disc diffusion method. The phytochemical analysis of the ethanol, acetone and aqueous extracts of the leaves of Andrographis paniculata showed the presence of phytochemicals (alkaloids, phenols, tannins, flavonoid, saponin, steroid, terpenoid, andrographolide and anthracyanin). Quantitative analysis of the extracts showed varied concentrations of the phytocomponents. At 200mg/ml, the ethanol and acetone extracts of Andrographis paniculata showed higher zones of inhibition on all the isolates. Ethanol extracts of the leaves showed the highest zones of inhibition at 25mm on Acinetobacter johnsonii strain JUQ303, 23mm on Pseudomonas rhodesiae strain YHBT5, 22mm on Acaligenes faecalis strain 2, 19mm Acaligenes faecalis strain N148 and 21mm on Acaligenes faecalis 3, respectively. The aqueous extracts showed the highest zone of inhibition at 14mm on Acinetobacter johnsonii, 12mm on Pseudomonas rhodesiae, 13mm on Alcaigenes faecalis strain 2, 10mm on Alcaligenes faecalis strain N148 and 9mm on Alcaligenes faecalis strain 3, respectively at the concentration of 200mg/ml. At lower concentrations of 12.5mg/ml, 6.25mg/ml, 3.125mg/ml and 1.56mg/ml, the aqueous extracts showed no inhibition on the tested isolates. The MIC of the ethanol extract of Andrographis paniculata leaves were recorded at 25mg/ml,12.5mg/ml, 50mg/ml, 25mg/ml and 100mg/ml. The MIC of the acetone extracts of Andrographis paniculata leaves were recorded at 50mg/ml, 25mg/ml,100mg/ml, 12.5mg/ml and 12.5mg/ml, while the MIC for the aqueous extract was recorded at 100mg/ml, 200mg/ml,100mg/ml, 100mg/ml and 100mg/ml on Acinetobacter johnsonii strain JUQ303, Pseudomonas rhodesiae strain YHBT5, Alcaligenes faecalis strain 2, Alcaligenes faecalis strain N148 and Alcaligenes faecalis strain 3, respectively. The MBC of the ethanol and acetone extract was recorded at 25mg/ml and 12.5mg/ml for Acinetobacter johnsonii, 12.5 and 12.5 for Pseudomonas rhodesiae, 25mg/ml and 25mg/ml for Alcaligenes faecalisstrain 2, 12.5mg/ml and 100mg for Alcaligenes faecalis strain N148 and 12.5mg/ml and 100mg/ml for Alcaligenes faecalis strain 3, respectively. The aqueous extract showed no bactericidal effect on the tested isolates. From the study, ethanol extracts of the leaves of Andrographis paniculata showed the highest antibacterial potency on the clinical pathogens isolated from diabetic foot ulcers than the acetone and aqueous extracts. Andrographis paniculata plant is easily accessible, potent, economical and safe to man. Therefore, this study encourages the use of plant extracts in the treatment of human diseases caused by these pathogens.