This paper reviewed the diversity of endophytic fungi and their interactions with medicinal plants, along with the research methodologies utilized to investigate these interactions. It mainly includes the diversity of endophytic fungi, as well as distribution diversity, species diversity, and the diversity of their metabolites and functions, including antibacterial, anti-inflammatory, anti-tumor, insecticidal, antioxidant capabilities, and so on. The research methodologies employed to investigate the interactions between endophytic fungi and medicinal plants are categorized into metagenomics, transcriptomics, metatranscriptomics, proteomics, and metabolomics. Furthermore, this study anticipates the potential applications of secondary metabolites derived from endophytic fungi in both medicine and agriculture.

Cinnamon essential oil (CEO), a safe, medicinal, and edible Traditional Chinese Medicine (TCM) component, was investigated for its anti-Candida albicans property and ability to relieve intestinal inflammation. The anti-Candida albicans ability of CEO was evaluated by Minimum Inhibitory Concentration (MIC), 2,3-Bis-(2-Methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT), and Scanning Electron Microscope (SEM) methods. By constructing ulcerative colitis (UC) mice intestinally colonized by C. albicans, the CEO effects on the regulation of flora, the relief of intestinal inflammation, and possible related signal pathway were discussed. The results showed that CEO has a significant effect on inhibiting C. albicans, where the MIC₈₀ value was 265 μg/mL, and the Sessile Minimum Inhibitory Concentration (SMIC)₈₀ value was 530 μg/mL. SEM showed the CEO could inhibit C. albicans mycelium growth and biofilm formation. CEO can regulate the flora disturbance, reduce inflammatory factors level, and play a protective role in intestinal mucosal damage. Network pharmacology predicts CEO may be associated with Janus Kinase-Signal Transducer and Activator of Transcription (JAK-STAT) pathway. It was proved that CEO had an inhibitory effect on the JAK-STAT pathway by qPCR determination. These findings suggest CEO may have therapeutic potential for C. albicans–associated UC.