化妆品中复配防腐剂对健康成人面部皮肤常驻菌群的影响

Effects of compound preservatives in cosmetics on the resident flora of healthy facial skin

目的探究化妆品中4种常见复配防腐剂对体外培养的健康成人面部常驻菌群的抑菌活性。方法 使用微生物分离培养法从15名健康成人面部分离出皮肤常驻菌,并通过微生物质谱法对其进行鉴定,确认主要常驻菌。采用体外微量半倍稀释法测定市场上化妆品常用的复配防腐剂对羟基苯甲酸丙酯+咪唑烷基脲、苯氧乙醇+对羟基苯甲酸丙酯、苯氧乙醇+咪唑烷基脲、咪唑烷基脲+甲基异噻唑啉酮对6种主要面部常驻菌的最小抑菌浓度(MIC)和抑菌圈直径大小。结果 从15名健康成人面部分离鉴定出11种皮肤常驻菌,其中表皮葡萄球菌、头状葡萄球菌、痤疮丙酸杆菌、藤黄微球菌、坚强芽胞杆菌、鲁氏不动杆菌为主要常驻菌。咪唑烷基脲+甲基异噻唑啉酮对以上6种常驻菌均有较强抑制作用,MIC为(0.187 5+0.003 125)~(1.500 0+0.025 000)mg/mL,抑菌圈直径为21.98~30.90 mm,其中对痤疮丙酸杆菌最为敏感,MIC为(0.187 5+0.003 125)mg/mL,远远低于规定使用上限,抑菌圈直径均值为30.90 mm;对羟基苯甲酸丙酯+咪唑烷基脲的MIC分别为(0.125+0.187 5)~(1.000+1.500 0)mg/mL,抑菌圈直径分别为21.81~25.35 mm;苯氧乙醇+咪唑烷基脲的MIC分别为(0.031 25%+0.187 5 mg/mL)~(0.250 00%+0.750 0 mg/mL),抑菌圈直径分别为21.11~27.77 mm;苯氧乙醇+对羟基苯甲酸丙酯的MIC分别为(0.5%+0.5 mg/mL)~(1.0%+1.0 mg/mL),抑菌圈直径为10.74~12.46 mm。结论 咪唑烷基脲+甲基异噻唑啉酮对健康成人面部皮肤主要常驻菌抑制作用最强,其次是对羟基苯甲酸丙酯+咪唑烷基脲和苯氧乙醇+咪唑烷基脲,苯氧乙醇+对羟基苯甲酸丙酯抑菌活性较弱。长期连续使用含复配防腐剂的化妆品可能存在抑制面部皮肤常驻菌的风险,进而影响皮肤健康。

Objective To observe the bacteriostatic activity of four common compound preservative combinations in cosmetics on healthy facial resident flora cultured in vitro.Methods Skin-resident bacteria were isolated from the faces of 15 healthy adults using microbial isolation and purification cultures,and identified with microbial mass spectrometry to confirm the major resident bacteria.In vitro micro-and half-fold dilution methods were used to determine the minimum inhibitory concentrations(MICs) and inhibitory circle diameters of the combinations of Propyl p-hydroxybenzoate + Imidazolidinyl urea,Phenoxyethanol + Propyl p-hydroxybenzoate,Phenoxyethanol + Imidazolidinyl urea,and Imidazolidinyl urea +Methylisothiazolinone against six major facial resident bacteria.Results Eleven skin-resident bacteria were isolated from the 15 healthy adults,six of which were the major resident bacteria:Staphylococcus epidermidis,Staphylococcus cephalosporus,Propionibacterium acnes,Micrococcus luteus and Fusobacterium ruber.The combination of Imidazolidinyl urea + Methylisothiazolinone had strong inhibitory effects on all the major resident bacteria,with MICs of(0.187 5+0.003 125) to(1.500 0+0.025 000) mg/mL;the diameters of inhibitory circles ranged from 21.98 mm to 30.90 mm,to which Propionibacterium acnes was the most sensitive,with MIC of(0.187 5+0.003 125) mg/mL,much lower than the upper limit of the prescribed use,and the mean value of inhibitory circle diameter was 30.90 mm.The MIC of the combination of Propyl p-hydroxybenzoate + Imidazolidinyl urea was(0.125+0.187 5) to(1.000+1.500 0) mg/mL,and its diameter of inhibitory circle was 21.81 mm to 25.35 mm.The MIC of the combination of Phenoxyethanol + Imidazolidinyl urea was(0.031 25%+0.187 5 mg/mL) to(0.250 00%+0.750 0 mg/mL).The MIC of Phenoxyethanol + Propyl p-hydroxybenzoate ranged from(0.5%+0.5 mg/mL) to(1.0%+1.0 mg/mL),and the diameter of inhibitory circle ranged from 10.74 mm to 12.46 mm.Conclusion The combination of Imidazolidinyl urea + Methylisothiazolinone has the strongest inhibitory effect on the major resident bacteria of facial skin in healthy adults,followed by the combination of Propyl p-hydroxybenzoate + Imidazolidinyl urea and Phenoxyethanol + Imidazolidinyl urea,and lastly the combination of Phenoxyethanol +Propyl p-hydroxybenzoate,which has a weaker bacterial inhibitory activity.Long-term continuous use of cosmetic products containing compound preservatives may have the risk of inhibiting resident facial skin bacteria,which in turn may affect skin health.