Haukvik T, Bruzell E, Kristensen S, Tønnesen H H
University of Oslo, School of Pharmacy, Department of Pharmaceutics, Oslo, Norway.
Pharmazie. 2009 Oct;64(10):666-73.
Curcumin has potential as a photosensitiser (PS) in photodynamic therapy (PDT) for localised superficial infections. However, it is a challenge to make an optimal curcumin formulation in which curcumin has acceptable solubility and stability at physiological pH and combined with high selective phototoxic activity towards bacteria. In the present study, the phototoxic effects of curcumin against gram-negative and gram-positive bacteria were investigated in selected aqueous preparations. The gram-positive Enterococcus faecalis and Streptococcus intermedius and the gram-negative Escherichia coli were used as bacterial models. The bacteria were exposed to 1-25 microM curcumin solubilised in DMSO, cyclodextrines, liposomes and surfactants known to interfere with membranes. After 30 min incubation the bacteria were irradiated with fluorescent tubes emitting blue light (emission max 430 nm). The irradiance was 17 mW/cm2 and the radiant exposure (light dose) was 0.5-30J/cm2. The bacterial survival was calculated as a percentage compared to controls. Various post-irradiation incubation times were tested. Curcumin's native fluorescence was exploited in examination of curcumin uptake in or adherence to bacteria by fluorescence microscopy. Changes in post-irradiation incubation time, curcumin concentration, irradiation dose and preparation strongly influenced the phototoxic efficiency of curcumin in vitro. Aqueous preparations of DMSO, polyethyleneglycol and the pluronic block copolymer poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) were the most efficient vehicles for curcumin to exert photokilling of gram-positive and gram-negative bacteria.
姜黄素在用于局部浅表感染的光动力疗法（PDT）中具有作为光敏剂（PS）的潜力。然而，制备一种最佳的姜黄素制剂是一项挑战，在该制剂中姜黄素在生理pH下具有可接受的溶解度和稳定性，并对细菌具有高选择性光毒性活性。在本研究中，在选定的水性制剂中研究了姜黄素对革兰氏阴性菌和革兰氏阳性菌的光毒性作用。革兰氏阳性粪肠球菌和中间链球菌以及革兰氏阴性大肠杆菌被用作细菌模型。将细菌暴露于溶解在二甲基亚砜、环糊精、脂质体和已知会干扰膜的表面活性剂中的1-25微摩尔姜黄素。孵育30分钟后，用发射蓝光（最大发射波长430nm）的荧光灯管照射细菌。辐照度为17mW/cm²，辐射暴露（光剂量）为0.5-30J/cm²。将细菌存活率与对照相比计算为百分比。测试了各种辐照后孵育时间。通过荧光显微镜利用姜黄素的天然荧光来检查姜黄素在细菌中的摄取或粘附情况。辐照后孵育时间、姜黄素浓度、辐照剂量和制剂的变化强烈影响姜黄素在体外的光毒性效率。二甲基亚砜、聚乙二醇和普朗尼克嵌段共聚物聚（乙二醇）-嵌段-聚（丙二醇）-嵌段-聚（乙二醇）的水性制剂是姜黄素对革兰氏阳性菌和革兰氏阴性菌发挥光杀伤作用的最有效载体。
