terpeni

Terpeni, or terpenes, are a large and diverse class of organic compounds produced by many plants and some insects. They are built from isoprene units (C5H8) and are commonly classified by the number of units they contain: monoterpenes (two units), sesquiterpenes (three), diterpenes (four), and so on. Most terpenes are hydrocarbons, while many are oxygenated to form terpenoids.

Terpene biosynthesis occurs mainly via the mevalonate pathway or the non-mevalonate (MEP) pathway. Terpenes are abundant in essential oils and resins, contributing to the characteristic aromas of citrus, conifers, herbs, and other plants. Well-known examples include limonene, pinene, myrcene, linalool, and beta-caryophyllene.

In nature, terpenes play roles in defense against herbivores, attraction of pollinators, and chemical communication. In human use, they appear in perfumery, flavorings, cosmetics, and aromatherapy. Some terpenes exhibit biological activities that are studied for therapeutic potential, including anti-inflammatory, antimicrobial, and analgesic effects, though results vary by compound, dose, and context.

Distinctions and safety: Terpenes are often discussed together with terpenoids when oxygen-containing derivatives are included. They are typically extracted from plants by steam distillation or cold pressing (as with citrus oils). Concentrated essential oils can cause irritation or sensitization, so proper handling and dosing are important. Regulatory status and guidelines differ across jurisdictions.