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DOI: 10.1055/s-0030-1264902
Reseda luteola extract RF-40 displays antioxidative, antiinflammatory and photoprotective activities in vitro, ex vivo and in vivo
The flavone luteolin is present in higher amounts in the dyers weld, Reseda luteola L. During the last few years antimicrobial, anticancer, antiinflammatory and antioxidative activities of luteolin have been described [1, 2]. Reactive oxygen species play a major role in ultraviolet-induced skin inflammation, photoaging and photocarcinogenesis. Therefore, we were interested in the antioxidant and ultraviolet-absorbing properties of a dry extract from Reseda luteola (RF-40) [3] rich in flavones (40% w/w), mainly luteolin. Spectrophotometric measurements with 1% (v/v) solution revealed similar extinction maxima in the UVB and UVA range for RF-40 and luteolin. Ultraviolet transmission below 370nm was <10%. The free radical scavenging activity of RF-40 was assessed using cell-free and cell-based assays. In the cell-free DPPH assay the IC50 of RF-40 was 37µg/ml (Luteolin:12µg/ml, Trolox: 25µg/ml; N-acetylcystein: 34µg/ml). In UVB irradiated (60 mJ/cm2) HaCaT cells the formation of DCFH was reduced by RF-40 and luteolin in a concentration-dependent manner. Luteolin (IC50 3µg/ml) and RF-40 (IC50 4µg/ml) were more effective compared to Trolox (IC50 12µg/ml) and N-acetylcystein (IC50 847µg/ml). Furthermore RF-40 inhibited the expression of inducible cyclooxygenase-2 ex vivo in UVB irradiated skin explants, and in vivo in suction blister roofs from human volunteers. In the suction blister fluid the UVB induced, cyclooxygenase-2 catalyzed synthesis of prostaglandin E2 was reduced by RF-40. These data suggest that due to its ultraviolet absorbing, antioxidant and antiinflammatory properties RF-40 is an interesting active ingredient for topical sun-protecting and anti-aging dermocosmetics.
References: 1. Seelinger G, Merfort I, Schempp CM (2008) Anti-oxidant, anti-inflammatory and anti-allergic activities of luteolin. Planta Med 74:1667–1677.
2. Seelinger G, Merfort I, Wölfle U, Schempp CM (2008) Anti-carcinogenic effects of luteolin and other flavonoids. Molecules 13:2628–51.
3. Wölfle U, Simon-Haarhaus B, Merfort I, Schempp CM. Reseda luteola L. extract displays antiproliferative and pro-apoptotic activities that are related to its major flavonoids. Phytotherapy Research (in press).