Overuse of antibiotics is one of the important factors that contribute to developing antimicrobial resistance. Many studies have been conducted to find out promising solutions to overcome the problems. Antimicrobial peptides (AMPs) are fundamental components of human innate immunity. They have an important role in the treatment of a wide range of diseases, including cancer, allergies, and also in warding off invading pathogens. In the case of infectious disease, the AMPs exhibit broad-spectrum activity against a wide range of pathogens including Gram-positive and -negative bacteria, yeasts, fungi, and enveloped viruses. These peptides have been isolated from various sources such as microorganisms, plants, invertebrates, and vertebrates. The peptides show distinct physicochemical and structural properties but most of them are small cationic peptides with amphipathic properties. In this review, an overview of the classification, antimicrobial activities, mode of action, and mechanism of resistance of human AMPs will be provided. These peptides are categorized into three main groups. The defensins are cationic peptides containing six cysteine residues with three intramolecular disulfide bridges. In humans, two classes of defensins could be found, α-defensins and β-defensins. The second group is cathelicidins that only one AMP, LL-37, has been found in humans. This peptide is derived from proteolytic digestion of the C-terminal of human CAP18 protein. The third group is the family of histatins that are small cationic histidine-rich peptides, and mainly present in human saliva. The last two groups have random coil conformation in hydrophilic environments and α-helices in a hydrophobic environment.

抗生素的过度使用是导致产生抗药性的重要因素之一。已经进行了许多研究以找到有希望的解决方案来克服这些问题。抗菌肽（AMPs）是人类先天免疫的基本组成部分。它们在治疗多种疾病（包括癌症，过敏症）和抵御入侵的病原体方面具有重要作用。在感染性疾病的情况下，AMP对多种病原体（包括革兰氏阳性和阴性细菌，酵母，真菌和包膜病毒）表现出广谱活性。这些肽已从多种来源分离，例如微生物，植物，无脊椎动物和脊椎动物。这些肽具有独特的理化和结构特性，但大多数是具有两亲特性的小阳离子肽。在这篇综述中，将概述人AMP的分类，抗菌活性，作用方式和耐药机制。这些肽分为三大类。防御素是包含六个半胱氨酸残基和三个分子内二硫键的阳离子肽。在人类中，可以发现两类防御素，即α-防御素和β-防御素。第二类是cathelicidins，在人类中仅发现一种AMP，LL-37。该肽源于人CAP18蛋白C端的蛋白水解消化。第三类是组蛋白家族，它们是富含组氨酸的小阳离子肽，主要存在于人唾液中。