Cucumis sativus (cucumber) fruit extract is used in cosmetics and personal care products due to its antioxidant, anti-inflammatory, and skin-conditioning properties.
The cucumber (Cucumis sativus) is a member of the gourd family, Cucurbitaceae, which also includes pumpkin, zucchini, watermelon, and squash. Botanically speaking, cucumbers are actually fruits because they are the part of flowering plants that contain the seeds and are the means by which such plants disseminate those seeds. The plant is cultivated throughout India and China, in particular, as well as in Europe and the United States.
Most types of cucumber are composed of 95% water. Despite this high concentration of water, the cucumber fruit contains a wide variety of beneficial nutrients, such as vitamins, minerals, amino acids, phytosterols, phenolic acids, fatty acids, and cucurbitacins. The major constituents that provide skin benefits include ascorbic acid (vitamin C), beta carotene, polysaccharides, and vitamin K.
Cucumis sativus (cucumber) fruit extract functions as an antioxidant, anti-inflammatory agent, and skin-conditioning agent in cosmetics and personal care products. Additionally, cucumber fruit extract contains fragrant components that are not sensitizing to skin, so it can be used to enhance the natural scent of a cosmetic product without issue.
As mentioned above, there are several antioxidants naturally found in cucumber fruit extract, for instance, ascorbic acid, beta carotene and caffeic acid. Cucumbers also contain antioxidant flavonoids, such as quercetin, apigenin, luteolin, and kaempferol, which provide additional benefits. A 2011 study published in the Archives of Dermatological Research determined that the ascorbic acid found in cucumber exhibited significant free radical scavenging activity. The researchers concluded that cucumber fruit extract warrants consideration for its potential used as an anti-wrinkle ingredient in cosmetic formulations.
Antioxidants limit oxidative damage caused by free radicals. Free radicals are dangerous because they are highly reactive and will try to become more stable by ripping electrons off all nearby molecules. This is problematic because free radicals can react with important cellular structures, like DNA, proteins, carbohydrates, or the cell membrane. Altogether, the damage to cells caused by free radicals is known as oxidative stress. The free radical theory of aging (FRTA) states that organisms age because cells accumulate oxidative stress caused by free radical damage over time. Thus, by using ingredients that are rich in antioxidants, like cucumber fruit extract, the skin will be better protected from free radicals.
Cucumber fruit extract also imparts anti-inflammatory effects when applied to the skin.
According to Dr. Joseph Mercola, animal studies suggest that cucumber extract helps reduce unwanted inflammation, in part by inhibiting the activity of pro-inflammatory enzymes (including cyclooxygenase 2, or COX-2). Ingredients that reduce inflammation will calm any skin redness and irritation, and may help to combat signs of aging.
Lastly, cucumber fruit extract effectively hydrates and conditions the skin due to its rich composition of polysaccharides. A polysaccharide is a carbohydrate whose molecules consist of a number of sugar molecules bonded together. Polysaccharides are good water-binding agents. After topical application, they create a gel-like layer on skin that acts as a barrier to attract and keep moisture in.
You may be familiar with the practice of placing slightly chilled cucumber slices over the eye to help reduce puffiness. Skin care expert Paula Begoun explains that this is not because the cucumber has de-puffing properties, but that the coolness of the slices constricts the skin and minimizes puffiness.
Even though cucumbers don’t directly reduce eye puffiness, their high content of vitamin K may help to minimize the appearance of dark circles. Vitamin K is required to produce prothrombin, a key factor involved in blood clotting, which is why vitamin K is thought to speed the healing of wounds and bruises. Applied to the skin, vitamin K may help to improve dark circles under the eyes in the same way it helps bruises to heal when taken internally.
Cucumber is a commonly consumed food and generally recognized as safe. The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of six Cucumis sativus (cucumber)-derived ingredients, including cucumber fruit extract, and found them safe in the present practices of use and concentration.
References: Wikipedia, “Cucumber”, Dermatology News, “Cucumber”, 2012, Arch Dermatol Res. 2011 May;303(4):247-52, Cosmetic Ingredient Review, “Cucumis Sativus (Cucumber) -Derived Ingredients as Used in Cosmetics”, 2012.