Determination of sun protection factor (SPF) of Rumex crispus and main anthraquinones

Sun protection factor (SPF) is a value, shows effectiveness of sunscreen and a higher SPF means more protection from UV radiation [1]. Major UV bands are UVA (400 – 320nm), UVB (320 – 290nm) and UVC (290 – 200nm). UV-A and UV-B are mainly responsible for skin hazards such as sunburn, cutaneous degeneration, photosensitivity and skin cancer [2]. Chemical molecules are in use for protection from sun, but they may have various adverse effects. It is preferred to use natural agents, which have higher Sun Protection Factor. The aim of the present study was to determine SPF values of Rumex crispus L. extracts and main anthraquinones. Rumex crispus L. (Polygonaceae) is known as yellow dock and emodin, aloe-emodin, rhein, physcion and chrysophanol are main anthraquinones of Rumex species [3]. The in vitro SPF number is determined according to the spectrophotometric method described by Mansur et al. [4]. Anthraquinones and ethanolic extracts of roots, leaves and fruits of R. crispus were prepared. After dilution, the absorbance were recorded between 290 – 320nm using UV-vis spectrophotometry. It was observed that all of the tested extracts and anthraquinones showed high UV protection capability. All samples were prepared as 100 µg/ml and 200 µg/ml concentration. According to results of main anthraquinones, emodin showed highest UV capability with SPF 20.23 (100 µg/ml) and SPF 30.59 (200 µg/ml) values. Root, leaf and fruit extracts of R. crispus showed similar results 13.56 (200 µg/ml), 15.01 (200 µg/ml), 15.36 (200 µg/ml), respectively. This study shows that main anthraquinone molecules and R. crispus extracts may be potential sunscreen agents.

Acknowledgements: This study was supported by The Scientific and Technological Research Council of Turkey (TUBITAK) (Project No: SBAG-214S147).

Keywords: Sunscreen, sun protection factor (SPF), anthraquinone, Rumex crispus.

References:

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