Endophytes are defined as microorganisms which live in plant tissues without causing any apparent negative effects to the host plant. Endophytes have been considered rich sources for natural products since they produce an array of chemically diverse bioactive secondary metabolites. Consistent with the hypothesis that endophytes help the survival and growth of host plants by producing secondary metabolites, many compounds derived from endophytes exhibit potent antimicrobial activity. Interestingly, some endophytes have been reported to produce the same metabolites as the host plants, probably due to horizontal gene transfer. In this review, metabolites produced by endophytes as well as their host plants are briefly introduced, with the emphasis on their value as pharmaceutical lead compounds. We have defined lead compounds as secondary metabolites with antimicrobial activities with Minimal Inhibitory Concentration values less than 20 μM (5 μg/mL). The endophytic metabolites with antimicrobial activities are classified into two groups according to the mode of inhibition: (1) antibiotic metabolites that kill or inhibit growth of microorganisms (2) endophyte-derived compounds with inhibitory activity against quorum sensing. Disruption of quorum sensing, which is a microbial communication system, has recently emerged as a novel target for antibiotic development since it affords a new modality to reduce microbial infection. Although currently there are no commercially-available antibiotics derived from endophytes, it is expected that new antibiotics based on several modes of action will be developed and marketed due to increasing research emphasis in this field.

内生细菌被定义为生活在植物组织中而不会对宿主植物造成任何明显负面影响的微生物。内生植物被认为是天然产物的丰富来源，因为它们会产生一系列化学上多样化的生物活性次生代谢产物。与内生菌通过产生次生代谢产物帮助宿主植物存活和生长的假设一致，许多内生菌衍生的化合物均表现出强大的抗菌活性。有趣的是，据报道某些内生菌可能产生与宿主植物相同的代谢产物，这可能是由于水平基因转移所致。在这篇综述中，简要介绍了内生菌及其宿主植物产生的代谢物，并着重介绍了其作为药物先导化合物的价值。我们将先导化合物定义为具有最小抑菌浓度值小于20μM（5μg/ mL）的具有抗菌活性的次生代谢产物。根据抑制方式，具有抗菌活性的内生代谢物分为两类：（1）杀死或抑制微生物生长的抗生素代谢物（2）具有抑制群体感应的活性的内生菌衍生化合物。群体感应（一种微生物通讯系统）的破坏最近已成为抗生素开发的新目标，因为它提供了一种减少微生物感染的新方法。尽管目前还没有任何可商购的内生细菌抗生素，