p-Terphenyls as Anti-HSV-1/2 Agents from a Deep-Sea-Derived Penicillium sp.

Guided by Global Natural Products Social molecular networking, two p-terphenyl derivatives and one 4,5-diphenyl-2-pyrone analogue, peniterphenyls A-C (1-3), together with five known p-terphenyl derivatives (4-8) and sulochrin (9), were obtained from a deep-sea-derived Penicillium sp. SCSIO41030. Their structures were elucidated using extensive NMR spectroscopic and HRESIMS data and by comparing the information with literature data. Peniterphenyl B (2) represented the first reported natural product possessing a 4,5-diphenyl-substituted 2-pyrone derivative. The p-terphenyl derivatives displayed inhibitory activities against HSV-1/2 with EC50 values ranging from 1.4 ± 0.6 to 9.3 ± 3.7 μM in Vero cells, which showed that they possessed antiviral activities with low cytotoxicity, superior to the current clinical drug acyclovir (EC50 3.6 ± 0.7 μM). Peniterphenyl A (1) inhibited HSV-1/2 virus entry into cells and may block HSV-1/2 infection through direct interaction with virus envelope glycoprotein D to interfere with virus adsorption and membrane fusion, and thus differs from the nucleoside analogues such as acyclovir. Our study indicated peniterphenyl A (1) could be a promising lead compound against HSV-1/2.