Canfora, the Italian word for camphor, refers to a waxy, flammable, translucent solid known for its strong, aromatic odor. This organic compound has been utilized across various cultures for centuries. Historically, camphor was incorporated into medicines, perfumes, and even sweets in regions from ancient India and Southeast Asia to the Middle East and Europe.
Sources and Properties of Camphor
Camphor naturally originates from the wood of the camphor laurel tree, Cinnamomum camphora, a large evergreen tree primarily found in East Asia, including China, Taiwan, and Japan. Traditional extraction involves steam distillation of the tree’s pulverized wood, where camphor crystallizes from the oily distillate upon cooling.
Most commercial camphor today is produced synthetically, primarily from turpentine oil or alpha-pinene, abundant in coniferous tree oils. Synthetic production converts pinene to camphene, followed by oxidation to yield racemic camphor. Regardless of its source, camphor is a white or transparent waxy solid that sublimes readily at room temperature, releasing its distinct scent. It has a melting point around 178°C to 180°C and is poorly soluble in water but dissolves well in organic solvents like ethanol.
Common Applications
Camphor finds widespread use in topical medicinal products, often included in over-the-counter creams and ointments. It functions as an analgesic for pain relief and is frequently found in chest rubs designed to suppress coughs and act as nasal decongestants. These products commonly include camphor in concentrations ranging from 3% to 11% for pain and itching relief, and less than 11% for cough suppression.
Beyond medicinal applications, camphor serves as an effective pest and moth repellent in household settings. Its strong aroma deters insects, making it a common component in mothballs. Camphor also holds significant cultural and religious meaning, particularly in Hindu ceremonies. It is often burned as incense during rituals like puja, symbolizing purification and the destruction of ego as it burns away without leaving residue.
How Camphor Interacts With the Body
When applied to the skin, camphor creates sensations of coolness or warmth by interacting with specific nerve endings. It achieves this by activating certain transient receptor potential (TRP) channels.
Specifically, camphor activates TRP vanilloid subtypes 1 (TRPV1) and 3 (TRPV3), which are sensitive to heat, contributing to the warm sensation. It also activates transient receptor potential melastatin 8 (TRPM8), a channel sensitive to cold, explaining the cooling effect.
Safety and Toxicity Concerns
Despite its widespread use, camphor is highly toxic if ingested, even in small amounts. Symptoms of camphor poisoning can appear rapidly, often within 5 to 15 minutes of ingestion, and may include nausea, vomiting, headaches, dizziness, and confusion. More severe neurological effects such as muscle twitching, delirium, hallucinations, and seizures can occur within 90 minutes.
Children are particularly susceptible to camphor’s toxic effects, with doses as low as 0.5 to 1 gram considered potentially lethal in young children, and 70 mg/kg in infants. The U.S. Food and Drug Administration (FDA) has restricted the concentration of camphor in nonprescription medicinal products to less than 11%. Furthermore, camphorated oil, a product historically confused with other ingestible oils, was banned from nonprescription sale in the United States in 1980 due to accidental poisonings. It is important to use camphor products only externally and as directed, ensuring they are stored safely away from children.