Evaluating the antimicrobial and hematological effect of Justicia carnea leaf extract on selected bacterial species and albino rats

Abstract

Antibiotic-resistance is becoming a worldwide public health concern especially in terms of food-borne illness and hospital-acquired infections, which has led to intensify research into medicinal plants with antimicrobial and therapeutic potentials. This study investigated the effects of Justicia carnea (locally known as “Ogwu Obara” in Igbo and “Edit Idung” or “Edit Udia” in Ibibio) ethanolic leaf extract on the antimicrobial and some haematological parameters of albino rats. Fresh leaves of the plant were collected, washed, shade-dried at room temperature for 10 days, pulverized into a fine powder using an electric blender and extracted using ethanol. Antimicrobial sensitivity testing was conducted using the agar well diffusion method against selected bacterial species including; Escherichia coli, Staphylococcus aureus, Salmonella typhi, Klebsiella pneumonia, and Pseudomonas aeruginosa.  Thirty healthy albino rats (15 males and 15 females) were divided into control and experimental groups, and administered varying doses (100 mg/kg, 250 mg/kg, and 500 mg/kg body weight) of Justicia carnea extract for 14 days. Haematological parameters including: packed cell volume (PCV), haemoglobin concentration (HGB), red blood cell count (RBC), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), and total white blood cell count (TWBC), as well as differential WBC counts were determined using standard manual techniques. Data were analyzed using SPSS version 25, with results expressed as mean + standard deviation. Statistical comparisons between groups were done using Student’s t-test and ANOVA, with a significance level set at P<0.05. Results showed a dose-dependent increase in antimicrobial activity against test organisms, moreover, the phytochemical screening revealed the presence of flavonoids, tannins, phenols, alkaloids, glycosides, terpenoids and saponins. Furthermore, the results of antibacterial activity showed that the Justicia carnea extract exhibited significantly higher antimicrobial activity as shown by larger zones of inhibition and lower MIC values against the test organisms where Escherichia coli was the most susceptible organisms with a minimal inhibitory concentration at 50mg/ml zone of inhibition of 16.0 mm respectively.  PCV, HGB, and RBC in the treated groups which showed statistical significance compared to controls (P<0.05), among treated groups, indicating improved erythropoiesis. Conversely, total WBC and lymphocyte counts decreased, while monocyte and basophil percentages increased in treated groups compared to controls. These findings suggest that Justicia carnea possesses haematinic properties that could be beneficial in improving blood health.