Hepatic changes induced by Schrebera alata (Hochst): a preliminary report on the toxicology of II kau kawa.
Schrebera alata is a deciduous fuel tree from which the Samburu people in Northern Kenya obtain bark for medicinal purposes. A pharmacologically active principle that produces analgesic effects can be extracted from the bark with hot water. When administered to rats daily for a period of 6 weeks, the extract of bark (referred to as II kau kawa by the Samburu) caused reduced activities of succinic dehydrogenase, an enzyme that is involved in oxidative processes, and cholinesterase in heart and liver tissues. Histological sections from the liver revealed extensive cellular degeneration and small areas with necrotic lesions. Only that fraction of the bark extracts which contained components less soluble in alcohol produced such lesions within a 2 weeks period. The same fraction is associated with pharmacological activity. Since hepatic injuries occur frequently and the incidence of primary hepatic carcinoma is high in tropical areas, the role of natural toxins as aetiologic factors for cirrhotic conditions must be adequately clarified. It is apparent that bark from S.alata possesses some toxicity and its effects on the liver indicate it can contribute significantly to prevalent hepatocellular damages.