Synthesis of Borneol Mandelate and Its Acute Toxicity to Zebrafish

This study reports the synthesis of borneol mandelate from L-borneol, (R)-(-)-mandelic acid, and titanium sulfate, along with its characterization and acute toxicity assessment in zebrafish. The product was quantified by GC and structurally confirmed by IR, ¹H-NMR, and ¹³C-NMR spectroscopy. Optimization of the reaction parameters revealed that the highest crude product purity (91.7% by GC) was achieved under the following conditions: chloroform as solvent, mandelic acid-to-borneol molar ratio of 1.5:1, titanium sulfate-to-borneol mass ratio of 0.15:1, and a reaction time of 9 h. Acute toxicity testing on zebrafish showed that borneol mandelate exhibited a maximum non-lethal concentration (MNLC) of 29.6 μM and a 10% lethal concentration (LC10) of 31.2 μM. Treated zebrafish displayed multiple adverse effects, including decreased blood flow, microphthalmia, hepatic atrophy, delayed yolk sac resorption, and behavioral disturbances.