As a mild cationic antibacterial agent, hydroxypropyltrimethyl ammonium chloride chitosan (HACC) could kill gram-positive bacteria and gram-positive drug-resistant bacteria without cytotoxicity. Nevertheless, it was not effective against gram-negative bacteria. Herein, protocatechuic acid (PA) with broad-spectrum antibacterial properties and pharmacological activities was grafted on HACC. PA-g-HACC showed favourable antioxidant capacity and anti-inflammatory properties. Most importantly, the results of antibacterial assay indicated that the antibacterial rates of all PA-g-HACC groups against Staphylococcus aureus (S. aureus) and methicillin-resistant Staphylococcus aureus (MRSA) were above 92 %, and the antibacterial rate of PA-g-HACC against E. coli was increased with the amount of grafted PA. Furthermore, the cytocompatibility of PA-g-HACC was improved by appropriate grafting ratio of PA, while excessive grafted PA can lead to toxicity. We believe that PA-g-HACC in optimum grafting ratio of PA with favorable antibacterial properties, pharmacological activities and cytocompatibility will be potential antibacterial agent for treating infections.

羟丙基三甲基氯化铵壳聚糖（HACC）作为一种温和的阳离子抗菌剂，可以杀死革兰氏阳性菌和革兰氏阳性耐药菌而无细胞毒性。但是，它对革兰氏阴性菌无效。在此，将具有广谱抗菌特性和药理活性的原儿茶酸（PA）嫁接到HACC上。PA-g-HACC显示出良好的抗氧化能力和抗炎特性。最重要的是，抗菌测定的结果表明，所有PA-g-HACC组对金黄色葡萄球菌（S. aureus）和耐甲氧西林的金黄色葡萄球菌（MRSA）的抗菌率）大于92％，并且PA-g-HACC对大肠杆菌的抗菌率随PA含量的增加而增加。此外，通过适当的PA接枝率可以改善PA-g-HACC的细胞相容性，而过量的PA接枝会导致毒性。我们认为，以最佳的PA接枝率具有良好的抗菌性能，药理活性和细胞相容性的PA-g-HACC将成为治疗感染的潜在抗菌剂。