Turmeric is a familiar spice known for its vibrant color, but it also contains lesser-known compounds called turmerones. Distinct from the more famous curcumin, these bioactive molecules represent another facet of turmeric’s complex chemistry. They are classified as sesquiterpenes and include specific types such as ar-turmerone, α-turmerone, and β-turmerone.
The Source of Turmerones
Turmerones are primarily concentrated in the essential oil of the turmeric plant (Curcuma longa). This oil is extracted from the plant’s underground stems, known as rhizomes, which are the same parts that are dried and ground to make turmeric powder. The extraction process, often hydro-distillation, separates the volatile, oil-based components from the rest of the plant material.
The concentration of turmerones in common turmeric spice powder is significantly lower than in the essential oil. The drying and grinding process prioritizes the preservation of curcuminoids, flavor, and color. As a result, turmeric essential oil is the most direct source of turmerones, not the powdered spice used in cooking.
Distinguishing Turmerones from Curcumin
The primary difference between turmerones and curcumin lies in their chemical properties and solubility. Turmerones are fat-soluble (lipophilic) sesquiterpenes that make up the bulk of turmeric’s essential oil. In contrast, curcumin, the compound responsible for turmeric’s color, is a polyphenol from the curcuminoid group and is not readily soluble in fat.
Their structural differences mean they are found in different fractions of the turmeric rhizome and have different absorption pathways. Research suggests these two compounds may work together, as some studies indicate turmerones can enhance the bioavailability of curcumin. This interaction implies that the whole turmeric root may offer a synergistic effect that is absent when the compounds are isolated.
Investigated Biological Activities
Scientific inquiry has revealed several areas of potential biological activity for turmerones, separate from curcumin’s effects. One of the most studied areas is their neuroprotective properties. Research involving ar-turmerone in animal and cell-based models shows these compounds may support brain health. For example, some studies suggest ar-turmerone can inhibit microglia activation, while other preclinical research indicates it may stimulate neural stem cell proliferation.
Beyond the brain, turmerones have been investigated for their anti-inflammatory effects. This activity appears to operate through different mechanisms than those associated with curcumin, with research indicating they may modulate different inflammatory pathways. These properties have been observed in various preclinical models, suggesting a distinct contribution to the effects of turmeric.
Other preliminary research has explored additional activities. In laboratory settings, turmerones have shown antioxidant and anticancer properties, with ar-turmerone observed to induce apoptosis (programmed cell death) in certain cancer cell lines. This research is largely in vitro and has not been validated in human clinical trials.
Bioavailability and Consumption
The bioavailability of turmerones is influenced by their fat-soluble nature, as they are absorbed in the intestine alongside dietary fats. This property suggests that consuming turmerones with a source of fat could improve their absorption. Animal studies have shown that turmerones can be absorbed after oral administration and remain in the bloodstream for an extended period.
Given that turmeric powder contains low levels of turmerones, the most direct way to consume them is through turmeric essential oil or specialized supplements. These products are often formulated to contain a standardized amount of both turmerones and curcuminoids to capture the full profile of the rhizome.