Schempp C M, Lüdtke R, Winghofer B, Simon J C
Department of Dermatology, Photodermatology Unit, University of Freiburg, Germany.
Photodermatol Photoimmunol Photomed. 2000 Jun;16(3):125-8. doi: 10.1034/j.1600-0781.2000.d01-18.x.
St. John's wort (Hypericum perforatum) is a tradional folk remedy that is used for the topical treatment of superficial wounds, scars and burns. A characteristic metabolite of St. John's wort is the photodynamic active plant pigment hypericin. It is known that hypericin may cause a severe photodermatitis called hypericism when higher amounts of St. John's wort are ingested orally. To date, no reports on the photosensitizing capacity of topical application of St. John's wort are available. Here, we investigated the effects of Hypericum oil (hypericin 110 microg/mL) and Hypericum ointment (hypericin 30 microg/mL) on skin sensitivity to solar simulated radiation. Sixteen volunteers of the skin types II and III were tested on their volar forearms with solar simulated radiation for photosensitizing effects of Hypericum oil (n=8) and Hypericum ointment (n=8). The minimal erythema dose (MED) was determined by visual assessment, and skin erythema was evaluated photometrically. With the visual erythema score, no change of the MED could be detected after application of either Hypericum oil or Hypericum ointment (P>0.05). With the more sensitive photometric measurement, an increase of the erythema-index after treatment with the Hypericum oil could be detected (P< or =0.01). The results do not provide evidence for a severe phototoxic potential of Hypericum oil and Hypericum ointment, detectable by the clinically relevant visual erythema score. However, the trend towards increased photosensitivity detected with the more sensitive photometric measurement could become relevant in fair-skinned individuals, in diseased skin or after extended solar irradiation.
圣约翰草（贯叶连翘）是一种传统民间药物，用于浅表伤口、疤痕和烧伤的局部治疗。圣约翰草的一种特征性代谢产物是具有光动力活性的植物色素金丝桃素。已知当口服较多量的圣约翰草时，金丝桃素可能会引起一种称为金丝桃素中毒的严重光性皮炎。迄今为止，尚无关于圣约翰草局部应用的光敏能力的报道。在此，我们研究了金丝桃油（金丝桃素110微克/毫升）和金丝桃软膏（金丝桃素30微克/毫升）对皮肤对模拟太阳辐射敏感性的影响。对16名II型和III型皮肤的志愿者的掌侧前臂进行测试，以评估金丝桃油（n = 8）和金丝桃软膏（n = 8）对模拟太阳辐射的光敏作用。通过视觉评估确定最小红斑剂量（MED），并通过光度法评估皮肤红斑。根据视觉红斑评分，应用金丝桃油或金丝桃软膏后未检测到MED的变化（P>0.05）。使用更敏感的光度测量方法，可以检测到用金丝桃油治疗后红斑指数增加（P≤0.01）。结果未提供证据表明通过临床相关的视觉红斑评分可检测到金丝桃油和金丝桃软膏具有严重的光毒性潜力。然而，使用更敏感的光度测量方法检测到的光敏性增加趋势在皮肤白皙的个体、患病皮肤或长时间太阳照射后可能具有相关性。
