A Green and Solvent-Free Process for Preparation of High- Purity (–)-Borneol from Leaves of Blumea balsamifera (L) DC

Purpose: To develop a simple and low cost process for the preparation of high-purity (–)-borneol from leaves of Blumea balsamifera (L.) DC.. Methods: An improved hydrodistillation (IHD) equipped with a vertical condenser tube was designed for extracting the volatiles (crude (–)-borneol) without solvent, and comparing with hydrodistillation-solvent extraction (HDSE) and simultaneous distillation and extraction (SDE). The sublimation was used to separated high-purity (–)-borneol. The purities of (–)-borneol products were quantitatively analyzed by gas chromatography (GC), and the (–)-borneol product was analyzed by optical activity and nuclear magnetic resonance (NMR), and the antimicrobial activity was evaluated. Results: The (–)-borneol content of the volatiles was 82 % in IHD, and much higher than that of HDSE (45 %) and SDE (44 %). After sublimation, the purity of separated (–)-borneol was 92 %, and the recovery was 96 %. The NMR spectral data confirmed that the product was (–)-borneol, and the specific rotation was –36.4° (20 °C, ethanol). Meanwhile, the performances of the (–)-borneol product and standard (–)-borneol were the same in antimicrobial activity. Conclusion: The work provides a green, efficient and solvent-free process for preparation of high-purity natural (–)-borneol from B. balsamifera leaves.