Heat Treatment Improves UV Photoprotective Effects of Licorice in Human Dermal Fibroblasts

Abstract

External stimulation of the skin by ultraviolet B (UVB) radiation induces oxidative stress or inflammation, causing skin aging and skin cancer. Glycyrrhiza uralensis (licorice) has been used as a medicinal plant for its antioxidant, anti-inflammatory, antiviral, antimicrobial, anticarcinogenic, and hepatoprotective properties. The present study analyzed the effects of thermal processing on the bioactivities of licorice. Heat-treated licorice (HL) extracts had better antioxidant and anti-inflammatory activities than nontreated licorice (NL) extract. HL extracts also had higher total phenol contents than NL extract. In particular, contents of isoliquiritigenin, an antioxidant and anti-inflammatory substance of licorice, increased in proportion to the skin-protection effects of HL extracts. Heat treatment increased the contents of phenolic compounds such as isoliquiritigenin in licorice extract, which improved the UV photoprotective effect of licorice in human dermal fibroblasts.

Latilactobacillus sakei Wikim0066 Protects Skin through MMP Regulation on UVB-Irradiated In Vitro and In Vivo Model

“…Inflammatory cytokines can also affect skin aging [ 26 ]. UVB has been reported to stimulate inflammatory cytokines, such as IL-6, IL-1β, and TNF-α in fibroblasts [ 34 ]. TNF-a and IL-1β share several properties.…”

Antioxidant and Anti-Melanogenic Activities of Heat-Treated Licorice (Wongam, Glycyrrhiza glabra × G. uralensis) Extract

“…Glycyrrhiza uralensis Fischer (licorice) has antioxidant and UV photoprotective activities in human dermal fibroblasts [22]. However, the studies of comparison between Wongam (licorice) and other native species need to be conducted afterward.…”

“…Samples were prepared according to a previously reported method [22]. Licorice (Wongam, Glycyrrhiza glabra x G. uralensis, identified by Yun Ji Lee from NIHHS, RDA and registered in the Korea Medicinal Resources Herbarium with voucher number MPS006326) was cultivated and harvested at the Department of Herbal Crop Research (Eumsung, Chungcheongbuk-do, Korea) in 2018, and dried at 60 • C for 20 h. 10 kg licorice was harvested and 1 kg was ground.…”

“…A modified HPLC method was applied [22]. The ISL content of licorice extracts was analyzed by HPLC with a UV-visible detector (HPLC: 1200 series, Agilent Technologies, Santa Clara, CA, USA; column: SynergiTM, 250 × 4.6 mm, 4 µm, Fusion-RP 80 Å, Phenomenex, Torrance, CA, USA).…”