Sesquiterpene Lactones

Sesquiterpene lactones are a diverse group of naturally occurring plant compounds belonging to the larger terpenoid family. They are particularly common in plants belonging to the Asteraceae family, which includes dandelions, sunflowers, boneset, yarrow and many other flowering plants.

Thousands of different sesquiterpene lactones have been identified throughout the plant kingdom. Plants produce these compounds partly as natural chemical defences against insects, microorganisms and other environmental pressures.

For the Wellness Profiles, sesquiterpene lactones are interesting because researchers continue to investigate their relationships with inflammation, cellular signalling, oxidative stress, antimicrobial activity and other biological processes.

Much of this research remains laboratory, animal or preclinical research. Finding a sesquiterpene lactone in a plant does not mean that eating or drinking that plant will produce a particular medical effect.

What Are Sesquiterpene Lactones?

Sesquiterpenes are generally built from three five-carbon isoprene units, producing a 15-carbon framework.

A sesquiterpene lactone is a specialized type of sesquiterpene containing a lactone ring within its chemical structure.

Several structural groups exist, including:

• Germacranolides
• Guaianolides
• Eudesmanolides
• Pseudoguaianolides

Small differences in these chemical structures can significantly affect how individual compounds interact with biological systems.

Sesquiterpene lactones are particularly characteristic of the Asteraceae family. They can occur in roots, leaves, flowers and other plant tissues. Some also contribute to the characteristic bitterness found in certain plants.

Potential Health & Wellness Connections

Inflammation

One of the most studied areas involving sesquiterpene lactones is their relationship with inflammatory processes.

Laboratory research suggests that certain sesquiterpene lactones can interact with molecular signalling pathways involved in the body's inflammatory response.

This does not mean every plant containing these compounds has the same effect. Individual sesquiterpene lactones can behave differently, and the concentrations naturally present in foods and plants can vary considerably.

Oxidative Stress & Cellular Defence

Researchers have investigated certain sesquiterpene lactones for their interactions with cellular defence mechanisms and pathways associated with oxidative stress.

Oxidative stress occurs when the balance between reactive molecules and the body's ability to manage them becomes disrupted.

Understanding how naturally occurring plant compounds interact with these processes may eventually help researchers better understand the connections between plants, nutrition and human health.

Antimicrobial Research

Some sesquiterpene lactones have demonstrated antibacterial, antifungal or other antimicrobial activity under experimental conditions.

For plants themselves, these compounds can form part of their natural defence systems against microorganisms and other threats.

Laboratory activity does not necessarily mean eating a plant will provide the same antimicrobial effect in the human body.

Cellular Research

Sesquiterpene lactones are also being investigated for their interactions with cellular signalling and abnormal cell growth.

Some individual compounds have attracted scientific interest in cancer research because of the biological pathways they can influence.

This remains an area of biomedical research and should not be interpreted as evidence that plants containing sesquiterpene lactones can prevent, treat or cure cancer.

Native Ontario Plants

Several plants native to Ontario contain documented sesquiterpene lactones.

Common Boneset — Eupatorium perfoliatum

Common Boneset is native to Ontario and other parts of eastern North America.

Researchers have identified several sesquiterpene lactones among its phytochemical constituents. These compounds have contributed to scientific interest in the plant, particularly regarding inflammatory pathways and other biological activity.

Common Boneset has a history of traditional use, but historical use does not establish modern clinical effectiveness or safety.

Common Ragweed — Ambrosia artemisiifolia

Common Ragweed is native to Ontario and contains documented sesquiterpene lactones, including compounds belonging to the pseudoguaianolide group.

This plant provides an important health and wellness lesson: the presence of an interesting phytochemical does not automatically make a plant appropriate for food or herbal use.

Ragweed pollen is a major seasonal allergen for many people. It is included here to understand plant chemistry rather than as a recommended food or wellness plant.

Jerusalem Artichoke — Helianthus tuberosus

Jerusalem Artichoke, commonly called Sunchoke, is a North American member of the Asteraceae family.

Research examining the plant's leaf tissues has identified numerous sesquiterpene lactones.

Jerusalem Artichoke is especially interesting because its underground tubers are edible. However, finding particular compounds in the leaves does not mean the edible tubers contain those compounds at the same concentrations.

Easy Indoor Year-Round Plants

Dandelion — Taraxacum officinale

Dandelion contains several documented sesquiterpene lactones and is particularly useful for the Wellness Profiles because it can also be grown in relatively small spaces.

Sesquiterpene lactones identified from dandelion include compounds related to:

• Taraxinic acid
• Taraxinic acid β-D-glucopyranosyl ester
• Dihydrotaraxinic acid
• Dihydrolactucin
• Ixerin D
• Ainslioside

These compounds are found in different parts of the plant, including the roots and leaves, although their concentrations and distribution can vary.

Sesquiterpene lactones also contribute to some of the characteristic bitterness of dandelion.

Dandelion can be grown indoors in containers with sufficient light, nutrients, water and growing space. This makes it particularly interesting for people who do not have access to traditional gardens.

Leaves can be harvested while allowing the plant to continue growing, making dandelion an interesting plant for learning about food, phytochemicals and small-space growing.

Why Bitter Plants Are Interesting

Bitterness is sometimes viewed as something undesirable in food, but bitter flavours can tell us something about plant chemistry.

Sesquiterpene lactones are among the compounds responsible for bitterness in several plants.

Plants do not manufacture these chemicals specifically for humans. They are part of the plant's own biological survival system.

Some help discourage insects and animals from eating the plant. Others may help protect against microorganisms or environmental pressures.

When we grow and study these plants, we are learning about a complex chemical system that developed as part of the plant's relationship with its environment.

Plant Chemistry Is Complex

A single plant can contain hundreds of different natural compounds.

Sesquiterpene lactones may exist alongside:

• Polyphenols
• Flavonoids
• Phenolic acids
• Carotenoids
• Volatile oils
• Other terpenoids
• Vitamins
• Minerals
• Polysaccharides
• Plant pigments

The amount of an individual compound can also change depending on the plant.

Factors can include:

• Genetics
• Plant variety
• Growing conditions
• Light exposure
• Nutrient availability
• Temperature
• Environmental stress
• Plant maturity
• Harvest time
• Plant part
• Storage
• Preparation method

Even the roots, leaves and flowers of the same plant can have very different phytochemical profiles.

This is why identifying a compound is only the beginning of understanding its potential relationship with nutrition, health and wellness.

Growing, Learning & Nourishment

Sesquiterpene lactones provide another opportunity to connect growing, learning and nourishment.

Growing a plant such as dandelion in a small indoor space can become more than simply producing food.

It provides an opportunity to learn about plant biology, nutrition and phytochemistry.

Why does a dandelion taste bitter?

What compounds create that bitterness?

Why does the plant manufacture them?

What happens to those compounds when the plant grows under different conditions?

What does scientific research actually tell us about those compounds?

These questions help turn growing food into an opportunity for continued learning.

The Wellness Profiles are not about turning individual plants or phytochemicals into miracle treatments.

They are about understanding what is actually inside the plants around us, what science currently tells us, what remains uncertain, and how growing some of our own food can help us learn more about nutrition, plants, health and wellness.

Disclaimer

This Wellness Profile is provided for educational and informational purposes only and is not medical advice, diagnosis or treatment.

Research involving sesquiterpene lactones includes laboratory, animal, preclinical and, depending on the individual compound, limited human research. The presence of a compound in a plant does not establish that consuming that plant will prevent, manage or cure a health condition.

Some plants containing sesquiterpene lactones can cause allergic reactions, particularly in people sensitive to members of the Asteraceae family. Some plants containing these compounds may also be toxic or otherwise unsuitable for consumption.

Never consume a wild plant unless its identity and safety have been reliably established. Anyone who is pregnant or breastfeeding, has allergies or an existing health condition, or takes prescription or over-the-counter medications should speak with an appropriate qualified healthcare professional before using concentrated herbal preparations or making significant changes to their diet or wellness routine.

Wellness Profiles — Growing knowledge, understanding nutrition, and exploring the connections between plants, food, health and wellness.