# Anti-GPV activity of Lactobacillus-fermented traditional Chinese medicines

## TL;DR

This study shows that fermenting cold-natured Chinese herbs with Lactobacillus boosts their antiviral effects against Goose parvovirus and improves gut health.

## Contribution

The study introduces a novel approach of using Lactobacillus-fermented TCM to enhance antiviral activity against GPV.

## Key findings

- Fermentation increased active components like chlorogenic acid and gardenoside in TCM.
- Fermented TCM metabolites significantly suppressed GPV proliferation in vitro.
- Key components like quercetin modulate IL-6/TNF pathways to exert antiviral and anti-inflammatory effects.

## Abstract

Honeysuckle and gardenia are classified as cold-natured traditional Chinese medicinal herbs, with chlorogenic acid and gardenoside recognized as their major bioactive components. Modern pharmacological studies have confirmed their antiviral, anti-inflammatory, antioxidant, and immunomodulatory activities. However, research on the microbial fermentation of traditional Chinese medicine (TCM) for antiviral applications remains limited. This study aimed to investigate the antiviral activity against Goose parvovirus (GPV) of fermented TCM using Lactobacillus isolated from silage feed, and to explore its potential theoretical and practical value.

Lactobacillus plantarum was isolated and identified using standard microbiological methods, and its probiotic properties were evaluated. The in vitro antiviral activity of bacterial cells and their metabolites was assessed using cellular models, including the cell counting kit-8 (CCK-8) assay and quantitative PCR (qPCR). High-performance liquid chromatography (HPLC) was employed to analyze changes in active components of TCM following lactic acid fermentation. In addition, network pharmacology and molecular docking analyses were performed to elucidate the potential mechanisms of action.

A strain of Lactobacillus plantarum with strong acid and bile salt tolerance (survival rate > 92%) was successfully isolated. The strain effectively inhibited pathogenic bacteria and demonstrated safety in mice. In vitro experiments showed that bacterial metabolites significantly suppressed GPV proliferation. Fermentation markedly increased the contents of active components, including chlorogenic acid and gardenoside, in honeysuckle and gardenia decoctions. Moreover, the fermented mixed decoction exhibited a highly significant anti-GPV effect. Network pharmacology and molecular docking analyses indicated that key active components, such as quercetin, exert antiviral, and anti-inflammatory effects mainly through the regulation of Toll-like receptor–related signaling pathways involving targets such as IL-6 and TNF.

This study demonstrates that L. plantarum, TCM, and their fermentation products effectively alleviate GPV infection and improve intestinal barrier function. HPLC and network pharmacology analyses suggest that fermentation-derived active components, including chlorogenic acid, gardenoside, quercetin, and organic acids, may synergistically enhance antiviral and anti-inflammatory effects by modulating IL-6/TNF-related signaling pathways and interacting with the gut microbiota.