Introduction to Borneol

1. Classification of Borneol

Borneol is a monoterpenoid derivative with an aromatic odor, molecular formula C₁₀H₁₈O, and is an important component in traditional Chinese medicine and fragrances. It is widely used in pharmaceuticals, perfumery, and the daily chemical industry. Borneol can be classified into natural borneol and synthetic borneol, differing in their sources, production methods, and certain physical and chemical properties.

– Synthetic Borneol: Synthetic borneol is produced by chemical processes involving oxidation and reduction of materials like terpineol. It is commonly used in large-scale industrial production and is characterized by its high purity and stability.

– Natural Borneol: Natural borneol is extracted from plants such as the camphor tree (Cinnamomum camphora) and other Lauraceae plants like Dryobalanops camphora. Depending on the optical rotation, natural borneol can be divided into levorotatory borneol and dextrorotatory borneol, with dextrorotatory borneol typically having a higher content and more significant medicinal effects.

2. Chemical Properties and Structure

Borneol is a colorless, transparent, or white semi-transparent brittle crystal with a fragrant, cool taste and volatility. It is easily soluble in organic solvents such as ethanol and ether but almost insoluble in water. The melting point of borneol is between 205–210°C, and its optical rotation varies by type:
– Levorotatory Borneol: Extracted from natural camphor plants, has a negative optical rotation.
– Dextrorotatory Borneol: Mainly derived from Dryobalanops and camphor trees, has a positive optical rotation with a content of no less than 96.0%.
– Racemic Borneol: Produced from synthetic borneol, does not have optical activity, and is often used in industrial and pharmaceutical fields.

3. Biosynthesis and Artificial Synthesis

The biosynthesis of natural borneol involves the mevalonate pathway and the catalysis by geranyl diphosphate synthase, ultimately forming borneol. Synthetic borneol can be produced by reducing camphor via the Meerwein–Ponndorf–Verley reduction reaction, often using sodium borohydride to accelerate the reaction and improve yield.

4. Functions and Applications

Borneol is widely used in the medical field for resuscitation, clearing heat, and relieving pain. It is suitable for symptoms such as fever-induced coma, convulsions, stroke, and phlegm stagnation. In addition, it has antibacterial, anti-inflammatory, cardiovascular protective, and antithrombotic effects. Borneol is also used in the manufacture of perfumes, such as lavender and rosemary scents, and as a food additive in flavoring agents.

In the chemical industry, borneol is used as a fixative for paints and dyes as well as a preservative. It also has significant applications in tobacco flavoring and perfumes, providing a fresh and pleasant aroma.

5. Precautions

Borneol has certain dose-related toxicities, and excessive use may lead to adverse reactions. Therefore, dosage should be strictly controlled during use, especially for pregnant women who should use it with caution. Natural borneol, due to its different sources, has a greater market advantage in high-end pharmaceuticals and fragrance fields.

Conclusion

Borneol, as an important natural and synthetic compound, has extensive applications in the pharmaceutical, daily chemical, and fragrance fields. Its unique aroma and medicinal effects make it an important traditional Chinese medicine and industrial raw material.