title: A 56-Day Oral Toxicity Study of the Aqueous Extract ofRapanea melanophloeos(L.) Mez in Rats.
abstract: Rapanea melanophloeosis a tropical tree that is extensively utilized in African traditional medicine to treat helminthiases, tuberculosis, and heart-water. As with many other medicinal plants, there is insufficient information regarding the safety of therapeuticR. melanophloeosextracts. An aqueous extract ofR. melanophloeosstem bark was administered to Sprague Dawley rats at doses of 100 mg/kg, 300 mg/kg, and 1000 mg/kg for 56 days to characterize its potential toxicity after prolonged dosing. Blood samples were obtained fortnightly for serum chemistry and hematology, while organs were collected at the end of the study. The extract caused an increase in organ weight indices of the kidneys and testis at 300 mg/kg and 1000 mg/kg. Hematological and biochemical examination revealed a drop in leukocyte counts and the hematocrit at 1000 mg/kg dose level, while there was a general but nondose-related elevation in alkaline phosphatase activity. There were time-associated variations in the hematological and clinical chemistry parameters at days 28, 42, and 56 in all dose levels, but most values remained within physiological limits. No pathological lesions were evident at histopathology after treatment with the extract. Our data shows that the aqueous extract ofR. melanophloeosis not likely to be toxic at the doses tested and provides support to its medicinal use.
authors.affiliation: Department of Public Health, Pharmacology and Toxicology, University of Nairobi, P.O. Box 29053-00625, Nairobi, Kenya.
authors.forename: Hesbon Z
authors.identifier: 0000-0002-9320-3071
authors.initials: HZ
authors.lastname: Amenya
authors.affiliation: Department of Public Health, Pharmacology and Toxicology, University of Nairobi, P.O. Box 29053-00625, Nairobi, Kenya.
authors.forename: James M
authors.initials: JM
authors.lastname: Mbaria
authors.affiliation: Department of Clinical Studies, University of Nairobi, P.O. Box 29053-00625, Nairobi, Kenya.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Thaiyah
authors.affiliation: School of Pharmacy, University of Nairobi, P.O. Box 19676-00202, Nairobi, Kenya.
authors.forename: Grace N
authors.initials: GN
authors.lastname: Thoithi
authors.affiliation: Department of Veterinary Pathology, Microbiology and Parasitology, University of Nairobi, P.O. Box 29053-00625, Nairobi, Kenya.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Gathumbi