Known as sweet chestnut, Castanea sativa is a member of the Fagaceae family, and is found in abundance in Southern and Southeastern Europe and Asia.1 In traditional medicine, chestnut tree flower preparations have been used for various indications.2 Chestnut has been used in French folk medicine as a tea to treat severe cough, colds, and bronchitis as well as diarrhea.2-6 In modern times, C. sativa leaf extract has been described as having the capacity to scavenge various free radicals associated with oxidative stress induced by ultraviolet exposure.7
Traditional uses
A 2014 study of the therapeutic and traditional uses of the plants native to the Western Italian Alps revealed that C. sativa has long been important in the region, typically for food and wood.8 But medical uses have been uncovered in that region as well. In fact, ancient Romans found C. sativa to exhibit antibacterial, astringent, antitoxic, and tonic qualities, with chestnut honey used then to dress chronic wounds, burns, and skin ulcers.9 A 2014 study by Carocho et al. of the phytochemical profile and antioxidant activity of C. sativa flowers is noteworthy for buttressing the reported health benefits of the use of chestnut flower infusions and decoctions in traditional medicine.2
Antioxidant activity
In 2005, Calliste et al. investigated the antioxidant potential of C. sativa leaf to act against the stable free radical 2,2-diphenyl-1-pycrylhydrazyl, superoxide anion, and hydroxyl radical. Using electronic spin resonance, the investigators showed that C. sativa exhibited high antioxidant potential equivalent to reference antioxidants quercetin and vitamin E.3
Three years later, Almeida et al. conducted an in vitro assessment of an ethanol/water (7:3) extract from C. sativa leaves and an ethanol/water (2:3) extract from Quercus robur (English oak) leaves, finding that both plants demonstrated a high potency to scavenge various reactive oxygen and nitrogen species. The researchers concluded that these findings supported the burgeoning interest in these extracts for use in topical antioxidant formulations.4 An in vivo investigation using an ethanol/water (7:3) extract from C. sativa conducted by the same team later in the year yielded similar results, with the researchers concluding that chestnut extract has the potential to confer benefits against photoaging and other oxidative stress–mediated conditions when included in an appropriately formulated topical antioxidant preparation.6 Subsequently, Barreira et al. demonstrated that chestnut skin and leaves exhibited sufficient antioxidant potency to warrant use in novel antioxidant formulations.10
In 2015, Almeida et al. characterized an antioxidant semisolid surfactant-free topical formulation featuring C. sativa leaf extract. In the process of ascertaining the physical, functional, and microbiologic stability of the antioxidant formulation, the investigators identified a hydrating effect and good skin tolerance, which they concluded suggested a capacity to prevent or treat cutaneous conditions in which oxidative stress plays a role.11
Photoprotective potential
In 2010, Sapkota et al. evaluated the antioxidant and antimelanogenic characteristics of several prebloom and full-bloom chestnut flower extracts, finding that a prebloom methanol extract and an ethanol extract evinced the greatest levels of phenolic and flavonoid compounds. These extracts also displayed the best radical scavenging and mushroom tyrosinase–inhibiting activities. Notably, the prebloom extract was effective in protecting the skin from the deleterious impact of UV radiation. The investigators also observed that all of the tested extracts lowered the tyrosinase activity and melanin formation of SK-MEL-2 cells similarly to arbutin. They ascribed the antimelanogenic effects of chestnut flower extracts to their antioxidant-mediated inhibitory effects on tyrosinase. They concluded that chestnut flower extracts have considerable potential as cosmetic agents.12
Recently, Almeida et al. studied the protective effects in a human keratinocyte cell line of C. sativa extract at various concentrations (0.001-, 0.01-, 0.05-, and 0.1-mcg/mL) against UV-induced DNA damage. They found that the chestnut extract concentration dependently protected against UV-mediated DNA damage, with the 0.1-mcg/mL concentration affording maximum protection (66.4%). This result was considered to be a direct antioxidant effect attributed to various phenolic antioxidants present in C. sativa. In addition, the investigators observed no phototoxic or genotoxic effects on HaCaT cells incubated with up to 0.1 mcg/mL of chestnut leaf extract. They concluded that C. sativa leaf extract has the potential to prevent or mitigate UV-induced harm to the skin.7
Other benefits and bioactivity
Assessments of C. sativa by-products have shown a favorable profile of bioactive constituents that demonstrate antioxidant, anticarcinogenic, and cardioprotective activity. Braga et al. conducted a 2015 review that concluded these compounds, as part of agro-industrial waste, offer value to the pharmaceutical, cosmetics, and food industries, with the potential to lower pollution costs and raise profits while enhancing social, economic, and environmental sustainability in growing regions.1
A related chestnut species also has been linked to dermatologic uses. In East Asia, a skin firming/antiwrinkle formulation features the inner shell of Castanea crenata as an active ingredient.13 In 2002, Chi et al. showed that the chestnut inner shell extract improved cell-associated expression of the adhesion molecules fibronectin and vitronectin. They also found that scoparone (6,7-dimethoxycoumarin) isolated from the chestnut extract exhibited comparable qualities. The investigators concluded that the enhanced expression of adhesion molecules imparted by the chestnut inner shell extract may account for the prevention of cell detachment and the manifestation of antiaging effects.13
Allergy
It is worth noting that chestnut is one of the many allergens associated with the latex-fruit syndrome.14 However, in a patch test investigation of the skin irritation potential of C. sativa leaf extract in 20 volunteers, Almeida et al. identified five phenolic compounds in the extract (chlorogenic acid, ellagic acid, rutin, isoquercitrin, and hyperoside) and found it safe for topical application.6 Chestnut is considered to pose a low to moderate risk of inducing allergic reactions.9
Conclusion
Recent research appears to suggest the in vitro antioxidant activity of sweet chestnut and potential for use in topical formulations. There remains a paucity of in vivo evidence, however. While much more research is necessary to determine whether it has a place in the dermatologic armamentarium, current data are intriguing.
References
1. Nat Prod Res. 2015;29(1):1-18
2. Biomed Res Int. 2014;2014:232956
3. J Agric Food Chem. 2005 Jan 26;53(2):282-8
4. J Photochem Photobiol B. 2008 May 29;91(2-3):87-95
5. A Modern Herbal (vol. I). New York: Dover Publications, 1971, p. 195
6. Basic Clin Pharmacol Toxicol. 2008 Nov;103(5):461-7
7. J Photochem Photobiol B. 2015 Mar;144C:28-34
8. J Ethnopharmacol. 2014 Aug 8;155(1):463-84
9. J Sci Food Agric. 2010 Aug 15;90(10):1578-89
10. Food Sci Technol Int. 2010 June;16(3):209-16
11. Drug Dev Ind Pharm. 2015 Jan;41(1):148-55
12. Biosci Biotechnol Biochem. 2010;74(8):1527-33
13. Arch Pharm Res. 2002 Aug;25(4):469-74
14. Allergy. 2007 Nov;62(11):1277-81
Dr. Baumann is chief executive officer of the Baumann Cosmetic & Research Institute in the Design District in Miami. She founded the Cosmetic Dermatology Center at the University of Miami in 1997. Dr. Baumann wrote the textbook “Cosmetic Dermatology: Principles and Practice” (New York: McGraw-Hill, 2002), and a book for consumers, “The Skin Type Solution” (New York: Bantam Dell, 2006). Her latest book, “Cosmeceuticals and Cosmetic Ingredients,” was published in November 2014. Dr. Baumann has received funding for clinical grants from Allergan, Aveeno, Avon Products, Evolus, Galderma, GlaxoSmithKline, Kythera Biopharmaceuticals, Mary Kay, Medicis Pharmaceuticals, Neutrogena, Philosophy, Topix Pharmaceuticals, and Unilever.
