Hepatotoxic and nephrotoxic principles in Terminalia oblongata

Area of Science:

• Toxicology
• Plant Chemistry
• Veterinary Pathology

Background:

• Terminalia oblongata (yellow-wood) is a plant suspected of causing toxicity in livestock.
• Previous reports indicate liver lesions in ruminants exposed to yellow-wood.
• The specific toxic compound and mechanism remained uncharacterized.

Purpose of the Study:

• To identify and characterize the toxic principle(s) in Terminalia oblongata.
• To investigate the toxic effects of isolated compounds on animal models.
• To compare toxicity via different administration routes.

Main Methods:

• Crude aqueous extracts of yellow-wood leaf were prepared.
• Extracts and isolated fractions were administered to mice.
• Hepatotoxicity and nephrotoxicity were assessed through lesion analysis.
• Dose-response and route-of-administration studies were performed.

Main Results:

• Yellow-wood leaf extracts induced liver lesions similar to those seen in ruminants.
• The primary hepatotoxic compound was identified as punicalagin, a hydrolysable vegetable tannin.
• Oral administration required a dose at least 20 times higher than intraperitoneal administration to elicit toxicity.
• Punicalagin dosage correlated with the onset and severity of liver necrosis.
• An unidentified nephrotoxic substance was found, causing avascular renal necrosis independently of liver damage.

Conclusions:

• Punicalagin is the main hepatotoxic agent in Terminalia oblongata, responsible for liver necrosis.
• The route of administration significantly impacts punicalagin's toxicity.
• Terminalia oblongata contains at least two toxic principles: punicalagin (hepatotoxic) and an unidentified nephrotoxin.