Diurnal fluctuations of cocaine and potential precursors in leaves of Erythroxylum coca.
Level 5 - mechanism / opinion, no new human data
Bench research / botanical laboratory study with no human data (CEBM Level 5).
PubMed 8297424 · doi:10.1515/znc-1993-11-1208
What was done
Erythroxylum coca var. coca plants were grown in a controlled environmental growth chamber in soil at pH 3.5. After 17.5 months of growth, mature leaves (at least 35 days old) were harvested across a 24-hour cycle at 2-hour and 4-hour intervals. Arginine and phenylalanine concentrations were measured using HPLC, and cocaine content was quantified using GC/MS.
What was found
Cocaine concentrations exhibited diurnal variation across 24 hours, peaking at 8 hours (7.67 mg/g dry weight) and 16 hours (9.45 mg/g dry weight). Arginine declined between hours 6 and 12 before peaking at 13 hours (21.8 mg/g dry weight). Phenylalanine concentrations were lower overall than arginine and showed two peaks: at 8 hours (6.98 mg/g dry weight) and 14 hours (6.54 mg/g dry weight).
Why it matters
This demonstrates that cocaine and key amino acid biosynthetic precursors fluctuate rhythmically over a daily cycle under controlled growth conditions, informing optimal harvesting times and biosynthesis studies.
Limits
The abstract does not state the number of individual plants or biological replicates sampled. The study was conducted in an artificial growth chamber environment under specific soil conditions (pH 3.5), so findings may not directly reflect fluctuations in wild or field-grown plants exposed to variable natural conditions.
Cited by
- supports The potency difference between a coca leaf and purified cocaine is approximately 65 times.