Sesquiterpene lactones

Sesquiterpene lactones are a class of organic compounds that are derived from sesquiterpenes. They are a significant group of secondary metabolites found in many plants, particularly in the Asteraceae family. Sesquiterpene lactones are known for their diverse range of biological activities, including anti-inflammatory, anti-tumor, and anti-microbial properties.

Structure and Classification

Sesquiterpene lactones are characterized by a three-ring structure, typically with 15 carbon atoms, derived from three isoprene units. They contain a lactone group, which is a cyclic ester that contributes to their reactivity and biological activity.

They can be classified based on their core skeleton structure into several types, including germacranolides, eudesmanolides, guaianolides, and pseudoguaianolides. Each type has unique structural features and biological activities.

Biosynthesis

The biosynthesis of sesquiterpene lactones involves the mevalonate pathway, which is responsible for the production of terpenoids in plants. The process begins with the formation of farnesyl pyrophosphate (FPP), a sesquiterpene precursor. FPP is then cyclized by sesquiterpene synthases to form the basic sesquiterpene skeleton, which is further modified by various enzymes to produce different sesquiterpene lactones.

Biological Activities

Sesquiterpene lactones are known for their wide range of biological activities. Their anti-inflammatory properties are attributed to their ability to inhibit the NF-kappa B pathway, a key regulator of immune and inflammatory responses. They also exhibit anti-tumor activity by inducing apoptosis in cancer cells and inhibiting tumor growth.

In addition, sesquiterpene lactones have shown anti-microbial activity against various bacteria and fungi, making them potential candidates for the development of new antimicrobial agents.

Occurrence and Uses

Sesquiterpene lactones are found in many plants, particularly in the Asteraceae family, which includes species like artemisia, echinacea, and chamomile. They contribute to the plant's defense mechanisms against herbivores and pathogens.

In traditional medicine, plants containing sesquiterpene lactones have been used for their therapeutic properties. For example, artemisinin, a sesquiterpene lactone derived from the plant Artemisia annua, is a potent anti-malarial drug.

See Also

• Terpenes
• Lactones
• Secondary metabolites
• Asteraceae