Cornflower hydrosol, a natural anti-inflammatory to soothe irritations and redness.

The cornflower hydrosol is extracted by steam distillation of the dried flowers of the cornflower, a herbaceous plant also known as Centaurea cyanus. Originating from Europe, this plant has been renowned since antiquity for its various virtues. From the XVIth century, the cornflower was used for its anti-inflammatory and decongestant properties at the ocular level. It was even named "glasses-breaker" due to its potential benefits for the eyes. Since then, the cornflower hydrosol is often cited among the natural alternatives for combating inflammation.

As of today, there are no scientific studies directly addressing the anti-inflammatory effects of cornflower hydrosol.

Nevertheless, numerous studies have been conducted on a water-soluble extract of cornflower in rodents.

• An initial experiment, conducted on mice, compared the activity of an aqueous extract of cornflower blossoms to that of indomethacin (250 mg), a non-steroidal anti-inflammatory substance, on the inhibition of an oedema developed following the topical application of croton oil (40 mg diluted in 10 mL of acetone) on the inner surface of the mice's ears. The cornflower extract, tested at various doses (100, 200, 400 and 800 μg), demonstrated a dose-dependent inhibitory activity with a maximum oedema inhibition of 52% for the highest dose of extract, compared to a percentage of 72% achieved with indomethacin.

• A second experiment was conducted using the aqueous extract of cornflower in rats. Oedema was also induced following the intraperitoneal injection of carrageenan, a substance capable of triggering an inflammatory response. Similar to the previous experiment, different doses of cornflower extract (30, 60, 80 mg/kg) were administered via intraperitoneal injection to analyse their effectiveness in comparison with indomethacin (4 mg/kg) and acetylsalicylic acid (200 mg/kg). Once again, the extract demonstrated a dose-dependent effect with maximum efficacy achieved with the highest dose of extract, which resulted in a 45% inhibition rate. In parallel, indomethacin and acetylsalicylic acid showed an inhibition of 44% and 47% of the oedema respectively.

• A third experiment was conducted on rats, revealing an interaction between blueberry extract and the complement system, a group of proteins that are part of innate immunity. The extract appears to have the ability to inhibit the activity of anaphylatoxins, compounds produced following the activation of this system, which may play a role in triggering the inflammatory response. Anaphylatoxins could potentially trigger the release of inflammatory mediators, such as histamine or pro-inflammatory cytokines (TNF-α, IL-1α, IL-6). This possible interaction between blueberry extract and the complement system could be the source of its potential anti-inflammatory properties.

The aqueous extract of cornflower has thus shown interesting effects in reducing various oedemas and skin inflammations. However, it is important to remember that these experiments were conducted solely on rodents and not on humans. Furthermore, regarding the second experiment, the extract was not applied topically but by intraperitoneal injection. Finally, for all three experiments, the cornflower extract used does not exactly correspond to cornflower hydrosol: it is an aqueous extract obtained by solvent extraction using a Soxhlet extractor, unlike cornflower hydrosol derived from the steam distillation of dried flowers. Their chemical compositions, and potentially their properties, are thus different.

Although promising, the scientific evidence regarding the anti-inflammatory and anti-redness effects of cornflower hydrosol remains insufficient for the time being.

• MALING H. M. & al. Inflammation induced by histamin, serotonin, bradykinin and compound 48/80 in the rat: antagonists and mechanism of action. Journal of Pharmacology and Experimental Therapeutics (1974).

• ANGENOT L. & al. Anti-inflammatory and immunological effects of Centaurea cyanus flower-heads. Journal of Ethnopharmacology (1999).