Comparative lethality of coca and cocaine

Area of Science:

• Pharmacology
• Toxicology
• Ethnobotany

Background:

• Cocaine is a stimulant derived from the coca leaf (Erthroxylon coca).
• The comparative toxicity of purified cocaine versus crude coca leaf extracts is not well-established.
• Understanding the toxicological profile of coca leaf is crucial for both medicinal and illicit use contexts.

Purpose of the Study:

• To compare the acute lethal toxicity of cocaine hydrochloride (HCl) with a crude ethanol extract of coca leaf.
• To determine the median lethal dose (LD50) for both substances in a controlled animal model.
• To investigate the contribution of non-cocaine constituents in the coca leaf to its overall toxicity.

Main Methods:

• Male Swiss mice were administered varying doses of cocaine HCl and coca leaf extract via intraperitoneal injection.
• The vehicle used for suspension consisted of Tween 60, Arlacel 83, and distilled water.
• Mortality was recorded over a 24-hour period to calculate the LD50 values.

Main Results:

• The LD50 for cocaine HCl was determined to be 95.1 mg/kg.
• The LD50 for the crude coca leaf extract was significantly higher, at 3450 mg/kg.
• When adjusted for cocaine content, the LD50 of the extract was 31.4 mg/kg, indicating higher toxicity per unit of cocaine in the extract.

Conclusions:

• The crude coca leaf extract exhibits lower acute toxicity than purified cocaine on a per-weight basis.
• The calculated LD50 of the extract, adjusted for its cocaine content, suggests that other compounds in the coca leaf possess significant toxicity.
• These findings highlight the presence of additional toxic constituents within the coca leaf beyond cocaine itself.