Cucumis sativus is a member of the Cucurbitaceae family, which also includes pumpkin, zucchini, watermelon, and squash. Found growing wild in the Himalayan region and commonly referred to as cucumber in English, khira in Hindi, and sakusa in Sanskrit, the plant is cultivated throughout India and China, in particular, as well as in Europe and the United States (J. Young. Pharm. 2010;2:365-8).
It is grown as a food crop, with its fruit (the cucumber) found in many cuisines as well as a component in traditional medicine and folk cosmetics (Planta. Med. 2008;74:1785-8). Headache was one traditional indication; the fruit juice was used as a demulcent in antiacne lotions and the seeds were noted for their cooling and diuretic effects (J. Young. Pharm. 2010;2:365-8). In traditional Chinese medicine, the leaves, roots, and stems of the plant have been used to detoxify as well as to treat diarrhea and gonorrhea (Planta. Med. 2008;74:1785-8). Popularly, the application of cucumber slices to ameliorate swelling or dark circles under the eyes has long been accepted throughout the world as an effective treatment.
Hemera/thinkstock.com
The application of cucumber slices to ameliorate swelling or dark circles under the eyes has long been accepted throughout the world as an effective treatment, but cucumber may have other dermatologic uses.
Antioxidant Activity
In 2002, Villaseñor and coinvestigators assessed the comparative effectiveness of sugar beet roots, cucumber fruits, New Zealand spinach leaves, and turmeric rhizomes against dimethylbenz[a]anthracene-initiated and croton oil–promoted skin tumors in a Swiss Webster albino mouse model using three different protocols. The four species were selected based on prior findings of antioxidant activity and effectiveness in preventing skin tumors induced in laboratory settings. All four displayed antioxidant activity, and all were found to be effective in lowering skin tumor incidence and the number of skin tumors as well as delaying the onset of skin tumor formation, compared with the control, with turmeric exhibiting the greatest potency (Nutr. Cancer. 2002;44:66-70).
Melanin Suppressing Properties
In 2008, Kai and coinvestigators assessed six plant parts of C. sativus to compare their inhibitory effects on melanogenesis. They found that methanol extracts of the leaves and stems suppressed melanin production in cultured B16 mouse melanoma cells. Although they did not alter mushroom tyrosinase activity or crude enzyme lysate activity in these cells, the methanol extracts did reduce tyrosinase expression at the protein level. The researchers suggested that these findings indicate that the depigmenting activity of C. sativus extracts is associated with tyrosinase expression. They also found that lutein, of eight compounds isolated from the leaves, inhibited melanogenesis, significantly lowering tyrosinase expression. The investigators concluded that the leaves, and lutein in particular, of C. sativus effectively suppress tyrosinase expression and warrant consideration as a skin-whitening agent (Planta. Med. 2008;74:1785-8). Tyrosinase-inhibitory activity exhibited by cucumber extracts had also been previously attributed to enzymes found in cucumber skin (J. Agric. Food. Chem. 2003;51:7764-9).
In 2010, Kumar and coinvestigators evaluated the aqueous fruit extract of C. sativus for free radical scavenging and analgesic activities using in vitro and in vivo models. Preliminary phytochemical screening indicated that cucumber contains various classes of compounds known to exert antioxidant as well as analgesic activity, including flavonoids and tannins. The investigators found that the fruit extract showed maximum antioxidant and analgesic effect at 500 mcg/mL and 500 mg/kg, respectively, although the exact constituents of C. sativus fruits responsible for the promising effects were not elucidated by the study (J. Young. Pharm. 2010;2:365-8).
Research on Skin Care Properties
Early in 2011, Akhtar and coinvestigators reported on their efforts to formulate a topical water in oil (without) emulsion of 3% cucumber extracts, and to assess it according to multiple parameters, compared with its base (lacking cucumber ingredients) as a control, in 21 healthy volunteers over 4 weeks. The cucumber formulation demonstrated statistically significant reductions in sebum, as well as a decline in melanin content that was not statistically significant. Transepidermal water loss and erythema were elevated by the test formulation, but these changes were also not statistically significant. While identifying the need for more research, the authors concluded that their findings point to the potential for cucumber extracts to be effective ingredients in skin care agents for medical and cosmetic purposes (African J. Biotechnol. 2011;10:1206-16).
Later in 2011, Nema and coinvestigators subjected the lyophilized juice of C. sativus fruit to 1,1-diphenyl-2-picrylhydrazyl and superoxide radical scavenging assays in reference to butylated hydroxytoluene, and hyaluronoidase and elastase inhibitory assays in reference to oleanolic acid. The cucumber juice, rich in ascorbic acid, was found to exhibit significant free radical scavenging activity as well as potent antihyaluronidase and antielastase activity. The researchers concluded that C. sativus warrants consideration for its potential used as an antiwrinkle ingredient in cosmetic formulations (Arch. Dermatol. Res. 2011;303;247-52).