Studies on Ethnopharmacology, Antimicrobial Activity and Toxicity of Catha Edulis (Vahl.) Forssk.ex Endl. (Celestraceae) in Sprague Dawley Rats

Abstract

Catha edulis (Vahl.) Forssk. ex Endl. (Celastraceae) is a plant which is predominantly used for its euphoretic and stimulant actions. Other indigenous uses of the plant which have been reported include; treatment of Helminthiasis, toothache, asthma, gonorrhea, heartburn, diarrhoea and fatigue. Information on the antimicrobial efficacy and safety of Catha edulis (Vahl.) Forssk. ex Endl., from Embu County is limited. This study aimed at documenting the Ethnobotanical uses of Catha edulis (Vahl.) Forssk. ex Endl., which is grown in Embu County, antimicrobial properties and toxicity. Ethnobotanical data on Catha edulis (Vahl.) Forssk. ex Endl., was collected from 35 key informants using semi-structured questionnaire between July and November 2020. Antimicrobial efficacy of Catha edulis Acetone extracts (CEAC), Catha edulis Aqueous extracts (CEAQ), and Catha edulis Methanol extracts (CEMET) against Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans were determined by using micro broth dilution and agar well diffusion techniques. Changes in body weights, Haematological, and Biochemical parameters of female and male Sprague Dawley rats over a 28-day period were used to determine the toxicity of the plant extracts. The Haematological parameters which were evaluated included; White Blood Cells (WBC), Red Blood Cells (RBC), Lymphocytes (LYM), Haemoglobin (HGB), Mean Corpuscular Haemoglobin Concentration (MCHC), Platelets (PLT) and the Mean Corpuscular Volume (MCV). The Biochemical parameters which were evaluated included; Kidney function tests (KFT’s) such as Creatinine (CR), Urea (UR), Total protein (TP), and Albumin (ALB) and Liver function tests (LFT’s) such as Alanine amino transferase (AST), Alkaline phosphatase (ALP), Alanine transferase (ALT), Direct bilirubin (DB) and Total bilirubin (TB). All informants were married males who were over 50 years old in age and had at least a Primary level of education. The majority of the informants, who were mostly from Kithunthuri Sub Location had been practicing Traditional medicine for more than ten years and had received no formal training. The sources, local names, preparation, storage conditions, indications for Human and Veterinary uses, frequency of use, dosage, and side effects of Catha edulis (Vahl.) Forssk. ex Endl., were documented. The Aqueous, Methanol and Acetone plant extracts were ineffective against gram negative E.coli, P. aeruginosa and C. albicans (fungi). Moreover, the extracts had limited efficacy against gram positive B. cereus and S. aureus. The mean weight gains in female and male rats which were given low, intermediate or high doses of CEAQ orally were not significant statistically (p<0.05). Female rats demonstrated significantly greater (p<0.05) mean levels of DB and CR than male rats after receiving a 250 mg/kg dosage of CEAQ. Male rats, on the other hand, had significantly higher (p<0.05) average levels of UR, ALP, AST, ALT, and TP than female rats. There was no substantial difference in the mean levels of TB and Albumin in male and female rats at a dose of 250 mg/kg of CEAQ. The mean level of ALB was significantly greater (p<0.05) in female rats than male rats at a dose of 500 mg/kg of CEAQ. However, the average levels of ALP, AST, and ALT in male rats were significantly greater (p<0.05) than in female rats. There was no difference in the mean levels of UR, CR, TB, DB and TP in male and female rats at a dose of 500 mg/kg of CEAQ. At a dose of 1000 mg/kg of CEAQ, female rats had substantially greater (p<0.05) mean levels of UR, TB, and ALB than male rats. However, the average levels of CR, ALP, AST, and ALT, and TP in male rats were significantly greater (p<0.05) than in female rats. There was no statistically substantial change in the mean levels of DB and TB in male and female rats at a dose of 1000 mg/kg of CEAQ. The mean levels of WBC and LYM were significantly greater (p<0.05) in male rats than female rats at low and xviii intermediate doses of CEAQ. There was no substantial statistically change in the average levels of PLT, HGB, MCHC, RBC, and MCV in male and female rats at low and intermediate doses of CEAQ. The mean levels of WBC, LYM, and MCV were significantly greater (p<0.05) in male rats than female rats at a 1000 mg/kg dose of CEAQ. The average levels of PLT, HGB, MCHC, and RBC were significantly greater (p<0.05) in male rats than female rats at a 1000 mg/kg dose of CEAQ. Histopathological examination of the liver, spleen, kidney, heart, and testes of male and female rats revealed that high, intermediate and low doses of CEAQ resulted in local congestion of the cardiac and hepatic vessels. Moreover, high, intermediate and low doses of CEAQ resulted in localized interstitial connective tissue proliferation, multifocal kidney interstitial haemorrhage and localized tubular epithelium necrosis in the kidney in some female and male rats. However, there were no adverse effects on lungs and testes. The Ethnopharmacological relevance of Catha edulis (Vahl.) Forssk. ex Endl., which was collected from the Mbeere community was documented. The limited antimicrobial efficacy and observed toxicity limit the use of leaves for medicinal purposes from Catha edulis (Vahl.) Forssk. ex Endl.