The plant Chloranthus japonicus Sieb is known for its anticancer properties and mainly distributed in China, Japan, and Korea. In this study, we firstly investigated the diversity and antimicrobial activity of the culturable endophytic fungi from C. japonicus. A total of 332 fungal colonies were successfully isolated from 555 tissue segments of the medicinal plant C. japonicus collected from Qinling Mountains, China. One hundred and thirty representative morphotype strains were identified according to ITS rDNA sequence analyses and were grouped into three phyla (Ascomycota, Basidiomycota, Mucoromycota), five classes (Dothideomycetes, Sordariomycetes, Eurotiomycetes, Agaricomycetes, Mucoromycetes), and at least 30 genera. Colletotrichum (RA, 60.54%) was the most abundant genus, followed by Aspergillus (RA, 11.75%) and Diaporthe (RA, 9.34%). The Species Richness Index (S, 56) and the Shannon-Wiener Index (H′, 2.7076) indicated that C. japonicus harbored abundant fungal resources. Thirteen out of 130 endophytic fungal ethyl acetate extracts exhibited inhibitory activities against at least one pathogenic bacterium or fungus. Among of these, F8158, which was identified as Trichoderma cf. harzianum, exhibited good antagonistic capacities (the percent inhibition of mycelial growth ranged from 47.72~88.18) for different pathogens and has a potential application in biological control. In addition, it is noteworthy that the strain F8157 (Thanatephorus cucumeris, an opportunistic pathogen) showed antibacterial and antifungal activity, which is reported firstly in this study, and should be investigated further. Taken together, these results indicated that the endophytic fungi from C. japonicus may be of potential interest in screening bio-control agents and discovering of new bioactive compounds.

In this study, we aimed to explore the potential targets and functional mechanisms of Rk1 combined with Rg5 (Rk1+Rg5) against type II diabetes mellitus (T2DM). Network pharmacology and molecular docking were used to predict and verify the targets and signaling pathways of Rk1+Rg5 against T2DM. The results were further confirmed by a db/db mouse model and a model using PA-induced L6 cells. According to network pharmacology, a total of 250 core targets of Rk1+Rg5 towards T2DM were identified; the insulin resistance signaling pathways were enriched by KEGG. Results of molecular docking indicated good binding affinity of Rk1 and Rg5 to Akt1. In vivo and in vitro studies further showed that Rk1+Rg5 is an inhibitor of skeletal muscle insulin resistance. The results showed that Rk1+Rg5 significantly improved the hyperglycemic state of db/db mice, alleviated dyslipidemia, and promoted skeletal muscle glucose uptake. This phenomenon was closely related to the alleviation of the insulin resistance in skeletal muscles. Finally, the combination activated the Akt signaling pathway and promoted GLUT4 translocation to the cell membrane for glucose uptake. Altogether, our findings, for the first time, demonstrate that the combination of Rk1 and Rg5 could be beneficial for anti-T2DM, possibly involving ameliorated insulin resistance.