Calendula: What are the components of its oil?

Known for its ornamental features, the calendula is an annual or biennial herbaceous plant belonging to the Asteraceae family. It has also been used for medical purposes since the 12th century, particularly to alleviate wounds and skin inflammations. Even today, calendula is found in various forms in the field of cosmetics and is incorporated into sun creams, serums, balms, and gels. The various properties of the calendula come from its interesting biochemical composition. It should be noted that the molecules found within a calendula macerate vary depending on the neutral oil used for its production. However, generally, a calendula oil contains the following elements:

Calendula oil is enriched with fatty acids.

Obtained by macerating calendula flowers in a vegetable oil, calendula oil contains both saturated and unsaturated fatty acids, in varying proportions, depending on the carrier oil used. The main fatty acids found are oleic and linoleic acids, which are unsaturated fatty acids, and palmitic and stearic acids, which are saturated fatty acids. These molecules are particularly valued for their softening and healing virtues. Indeed, they possess film-forming properties, allowing them to strengthen the natural hydrolipidic film present on the skin's surface and limit water loss.

Furthermore, studies have shown that oleic acid can reduce the release of pro-inflammatory cytokines, molecules responsible for various discomforts, such as irritations and redness. Thus, oleic acid is an ally for soothing the skin. As for linoleic acid, it is a precursor in the synthesis pathways of several mediators that are highly active in neoangiogenesis and dermal regeneration. Linoleic acid is partly responsible for the healing properties of the calendula macerate.

The oil macerate of calendula contains terpenes and terpenoids.

The oil macerate of calendula is also a source of terpenes and terpenoids, molecules that belong to the class of hydrocarbons. Notably, we can mention the bisabolol and chamazulene, both having anti-inflammatory properties. For instance, bisabolol can inhibit the action of several pro-inflammatory cytokines, such as interleukin-1β, interleukin-6 (IL-1β and IL-6) and tumour necrosis factor (TNF-α). Moreover, bisabolol downregulates the activity of cyclooxygenase 2 (COX-2), an enzyme catalysing the conversion of arachidonic acid into prostaglandin H2, which is involved in inflammatory processes. The bisabolol is often considered as an ally for sensitive skin.

The calendula oil contains triterpenic alcohols.

The composition of calendula macerate also includes several triterpenic alcohols, such as faradiol, α- and β-amyrins, taraxasterol, lupeol, and arnidol and its esters. These molecules exert anti-inflammatory and antimicrobial effects. Notably, lupeol is capable of targeting key molecular pathways of inflammation that involve the nuclear factor kappa B (NF-κB) and Wnt/β-catenin. This compound has also demonstrated interesting antibacterial activity against microorganisms such as S. aureus, S. saprophyticus, E. coli, S. typhi and P. aeruginosa. These various effects suggest that lupeol, and by extension calendula oil, could have a positive effect on dermatoses such as acne.

Triterpenic saponins are part of the composition of calendula oil macerate.

Oleanolic acid glycosides and triterpenic saponins are also present in calendula oil. These molecules also possess anti-inflammatory and antimicrobial properties. For instance, oleanolic acid glycosides are capable of inhibiting the expression of cell adhesion molecules, which are heavily involved in inflammatory phenomena as they regulate the circulation of leukocytes, as well as the production of tumour necrosis factor-α (TNF-α) and the activation of nuclear factor-κB (NF-κB). On the other hand, studies in vitro have shown that these compounds can inhibit the growth of certain microorganisms, such as Staphylococcus aureus.

Carotenoids are found in calendula oil.

The calendula macerate also possesses antioxidant activity, derived from the numerous carotenoids it contains. Notably, these include rubixanthin, β-carotene, lutein, and flavoxanthin. These various molecules are characterised by their chemical structure rich in conjugated double bonds, enabling them to effectively trap and neutralise free radicals. In doing so, the carotenoids protect the skin from oxidative stress, which can cause several skin discomforts, such as hyperpigmentation, a lack of radiance in the complexion, or even an acceleration of skin ageing.

The oil macerate of calendula is a source of flavonoids.

Finally, quercetin, isorhamnetin, and kaempferol are found in the calendula oil macerate. These flavonoids are primarily known for their antioxidant properties. Indeed, they function by increasing the activity of superoxide dismutase (SOD), an enzyme whose role is to trap free radicals produced by metabolism. Flavonoids can also inhibit the release of plasma malondialdehyde (MDA) in the body. This compound is one of the end products of the oxidation of polyunsaturated fatty acids. A low MDA level indicates low lipid oxidation, and therefore low oxidative stress. Thus, the overall antioxidant activity of the calendula macerate can be partly explained by its flavonoid content.

Good to know : The calendula oil is obtained by macerating the flowers of the plant in a neutral vegetable oil. Maceration is necessary if you want to obtain an ingredient rich in fatty acids, as calendula flowers do not contain lipids. As for the carrier oil used, sunflower, olive, sesame and jojoba oils are often preferred because they are particularly stable.