Citrus Essential Oils and Inflammation: What Laboratory Research Is Beginning to Reveal

Where science meets soul, wellbeing begins with trust.  Notes from the Apothecary in Residence Jane Connor.

One of the guiding principles of The Living Apothecary is to remain curious about the relationship between traditional botanical knowledge, practitioner experience and modern research.

A 2025 study published in the journal Foods explored the anti-inflammatory activity of essential oils from six plants within the citrus family. The researchers compared essential oils derived from bitter orange blossom, sweet orange, Brazilian sweet orange, lemon, bergamot and dried mandarin or tangerine peel.

The study was conducted in laboratory cell models rather than in people. This distinction matters. The findings are promising, but they do not show that a citrus essential oil can treat an inflammatory condition in clinical practice.

What the research does offer is an intriguing insight into the chemistry of citrus oils and the biological pathways researchers are beginning to investigate.

What the Researchers Studied

The researchers used gas chromatography–mass spectrometry, commonly known as GC-MS, to identify the chemical constituents of each essential oil.

They then tested the oils using macrophage cells exposed to lipopolysaccharide, a substance commonly used in laboratory research to provoke an inflammatory response.

The researchers measured several inflammatory mediators, including:

• tumour necrosis factor-alpha, or TNF-α;

• interleukin-6, or IL-6;

• interleukin-1 beta, or IL-1β;

• nitric oxide;

• inducible nitric oxide synthase.

These substances are involved in inflammatory signalling within the body.

Tangerine Peel Essential Oil

Of the six citrus oils studied, essential oil from Citri Reticulatae Pericarpium produced the strongest overall anti-inflammatory response in the laboratory model.

Citri Reticulatae Pericarpium refers to the dried peel of mandarin or tangerine fruit, traditionally used within Chinese medicine.

The essential oil contained:

• D-limonene: 76.51%;

• alpha-pinene: 2.68%;

• linalool: 2.11%.

The researchers found that the oil reduced the production of several pro-inflammatory mediators and also reduced the expression of genes associated with inflammatory signalling.

The effects generally increased as the concentration of essential oil increased, suggesting a dose-responsive pattern within the cell model.

More Than One Active Compound

D-limonene was by far the most abundant compound in the tangerine peel oil.

However, one of the most interesting findings was that the compound identified as potentially important within the molecular modelling was not the most abundant constituent.

Alpha-bulnesene made up only 0.34% of the oil, yet computational analysis suggested that it may interact with NLRP3, a protein involved in inflammatory signalling.

This raises an important point about essential oils.

They are complex mixtures rather than single-ingredient substances.

Their activity may not depend solely upon the dominant constituent. Minor compounds may also contribute, either individually or through interactions with other components.

This reflects the broader aromatherapy principle that the whole oil may behave differently from one isolated chemical constituent.

The NLRP3 Inflammasome

The study identified the NLRP3 inflammasome as a possible molecular target.

The NLRP3 inflammasome is part of the immune system and helps the body respond to infection, cellular damage and other harmful stimuli. Excessive or prolonged activation has been associated with a range of inflammatory processes.

Using molecular docking and computer simulation, the researchers explored whether alpha-bulnesene could bind with NLRP3.

The modelling suggested a potentially stable interaction, but this remains a theoretical prediction.

Computer modelling can help researchers identify promising pathways for further investigation, but it does not prove that the same interaction occurs in a living person.

What This Study Does Not Prove

This research does not show that applying tangerine oil to the skin will treat inflammation.

It does not establish:

• an effective human dose;

• how much of the oil would be absorbed;

• how it would be metabolised;

• whether the same effects occur in living tissue;

• whether topical or inhaled use would produce the same biological response;

• whether the oil is effective or appropriate for a particular health condition.

The study used mouse macrophage cells and laboratory concentrations of essential oil.

Further animal studies and clinical trials would be needed before therapeutic claims could be made.

Why This Research Still Matters

Although this is early-stage evidence, it helps build a more detailed picture of essential oil chemistry.

The study suggests that citrus oils may influence more than mood and aroma alone.

Their natural constituents may interact with inflammatory signalling pathways, oxidative stress and cellular communication.

It also reminds us that two oils from the same botanical family are not necessarily interchangeable.

The chemical composition of an essential oil can vary according to:

• the plant species;

• the part of the plant used;

• geographical origin;

• climate;

• harvest time;

• extraction method;

• storage conditions.

In this study, even oils described as sweet orange or bergamot differed from chemical profiles reported elsewhere.

This is one reason responsible aromatherapy requires careful sourcing, formulation and botanical identification.

Citrus Within The Living Apothecary

Citrus oils already hold an important place within The Living Apothecary.

They can bring brightness, freshness and movement to a blend, while also helping create a sensory experience that feels uplifting, grounding or gently restorative.

One example is Radix, a blend of sweet orange, geranium and rosemary.

The tangerine peel oil examined in this study is not the same as the sweet orange used within Radix, and the research should not be used to claim that Radix produces the same laboratory effects.

However, the study contributes to a wider and growing understanding of citrus essential oil chemistry.

It encourages us to ask better questions:

What is present in the oil?

How was it produced?

Which constituents may be active?

How might those constituents work together?

What evidence exists in cells, animals and people?

These questions belong at the heart of evidence-aware aromatherapy.

From Laboratory Research to Responsible Practice

There can be a temptation to take a promising scientific result and turn it immediately into a therapeutic claim.

That is not the approach of The Living Apothecary.

Research such as this informs curiosity, education and formulation. It does not replace medical care, nor does it allow us to promise that an essential oil will treat disease.

Instead, it helps us understand the plants more deeply.

It allows us to appreciate that within the familiar scent of citrus lies an intricate chemical landscape that science is only beginning to explore.

Where Science Meets Soul

Traditional plant knowledge and modern laboratory science do not need to compete.

One offers generations of observation and use.

The other provides tools for investigating chemistry, mechanisms and biological activity.

Together, they invite a more thoughtful approach to botanical wellbeing: one that is open to possibility but careful with language.

At The Living Apothecary, research is not used to create certainty where certainty does not yet exist.

It is used to deepen understanding.

To ask better questions.

And to honour both the complexity of the plant and the trust of the person using it.

Reference

Pu, J., Cui, J., Yang, H., Cao, J., Xiao, S. and Cheng, G. (2025). The anti-inflammatory effects and molecular mechanism of Citri Reticulatae Pericarpium essential oil: a combined GC-MS and network pharmacology study. Foods, 14(9), 1455. https://doi.org/10.3390/foods14091455