Traditional Cough Remedy Decoded: How Zhike Pipa Granules Fight Bronchitis at the Molecular Level

A traditional Chinese patent medicine long used to calm coughs, thin phlegm, and ease labored breathing has now been put under the molecular microscope. In a study published in BMC Complementary Medicine and Therapies, a team of researchers from the Beijing Institute for Drug Control and China Traditional Chinese Medicine Co., Ltd. combined laboratory experiments with computational network pharmacology and molecular docking to map out exactly how Zhike Pipa Granules, commonly abbreviated as ZPG, act against bronchitis. The work offers one of the clearest pictures yet of how a multi-component herbal formula can simultaneously suppress inflammation, reduce mucus, and quiet the cough reflex through a web of protein targets and signaling pathways.

The clinical reputation of ZPG as an antitussive, expectorant, and anti-asthmatic remedy preceded the study, but its precise active constituents and mechanism of action had never been fully resolved. That gap is a familiar one in traditional Chinese medicine research: herbal formulas contain dozens or hundreds of chemical compounds, many of which may contribute modestly to a therapeutic effect, making it difficult to isolate which molecules matter most and which biological pathways they engage. The research team set out to close that gap by pairing wet-lab pharmacology with bioinformatic target prediction, a strategy increasingly used to translate centuries-old formulas into modern mechanistic language.

The experimental foundation of the study rested on well-established animal and cellular models. To test the cough-suppressing and phlegm-clearing properties of the granules directly, the researchers used an ammonia water-induced cough model in mice alongside a tracheal phenol red excretion assay, a classic method for measuring how effectively a treatment promotes the clearance of respiratory secretions. ZPG performed prominently in both assays, demonstrating significant antitussive and expectorant activity. These results confirmed that the formula’s clinical effects were reproducible under controlled laboratory conditions before any mechanistic work began.

With efficacy established, the team turned to inflammation, the central pathological driver of bronchitis. They established lung inflammatory injury models both in vivo and in vitro using lipopolysaccharide, or LPS, a bacterial endotoxin that reliably triggers a robust inflammatory response in lung tissue and in cultured cells. After treating the models with ZPG, the researchers measured inflammatory factor levels using enzyme-linked immunosorbent assay, or ELISA, across three biological compartments: cell culture supernatants, serum samples, and bronchoalveolar lavage fluid, the latter being the fluid recovered from washing the airways of the experimental animals. Across all three, ZPG treatment significantly reduced the levels of inflammatory factors, indicating that the formula dampens the inflammatory cascade systemically as well as locally in the lung.

To identify which of the formula’s many chemical constituents were driving these effects, the researchers applied network pharmacology, a discipline that treats drugs and diseases as interacting networks rather than single molecule-single target relationships. Components of ZPG were screened according to two standard filters: oral bioavailability, which estimates how much of a compound survives digestion and enters the bloodstream, and drug-likeness, a composite measure of whether a molecule has the structural and physicochemical properties typical of successful drugs. Component targets were retrieved from the Symmap database, while disease targets associated with bronchitis symptoms were pulled from the GenCLiP3 database. The intersection of these two target sets formed the computational hypothesis space for the rest of the study.

Using STRING and Cytoscape software, the team constructed a Chinese medicine-component-target interaction map, revealing which herbal ingredients connected to which human proteins. Gene Ontology and KEGG pathway enrichment analyses were then performed on the key targets to identify the biological processes and signaling pathways most heavily represented. The analysis showed that ZPG exerts its antitussive and antiasthmatic functions mainly through targets such as ESR1, the estrogen receptor; DPP4, an enzyme involved in immune regulation; and MAPK14, a central kinase in stress and inflammatory signaling. Its expectorant and antiasthmatic functions were linked to targets including PPARG, a nuclear receptor that modulates inflammation; CASP3, a key executioner of programmed cell death; and INS, the insulin gene product. The full triad of antitussive, antiasthmatic, and expectorant effects converged on targets such as PTGS2, the cyclooxygenase enzyme better known as COX-2; AKT1, a hub kinase in cell survival signaling; and TNF, tumor necrosis factor, one of the most potent pro-inflammatory cytokines in the body.

The component-level analysis produced a shortlist of star molecules. Epigallocatechin gallate, or EGCG, the abundant catechin found in green tea; quercetin, a widely distributed plant flavonoid; kaempferol, another common dietary flavonoid; and beta-sitosterol, a plant sterol, emerged as the key components likely responsible for the formula’s comprehensive effects in relieving cough, reducing phlegm, and easing asthma. That several of these compounds are well-characterized polyphenols with documented anti-inflammatory activity lends biological plausibility to the network predictions, and it suggests that the therapeutic power of ZPG may derive less from exotic rare compounds and more from high concentrations of potent common phytochemicals acting in concert.

To test whether the predicted component-target interactions were physically plausible, the researchers performed molecular docking using AutoDockTools and PyMOL 2.6. Docking computationally fits a small molecule into the three-dimensional binding pocket of a protein and scores the strength of the predicted interaction. The results demonstrated strong binding between the key components, quercetin, EGCG, and kaempferol, and the key target proteins PTGS2, AKT1, and TNF. In other words, the flavonoids identified by network analysis are structurally capable of engaging the very proteins that sit at the center of the inflammatory and survival pathways implicated in bronchitis, providing a computational bridge between chemistry and pharmacology.

The enrichment analyses tied the whole picture together at the pathway level. GO and KEGG analyses identified numerous target genes and signaling pathways closely related to inflammatory responses, with the HIF-1 pathway, which governs cellular responses to low oxygen and is activated in inflamed airway tissue; the IL-17 pathway, a hallmark of neutrophil-driven airway inflammation; and the JAK-STAT pathway, a canonical cytokine signaling route, standing out as the routes through which ZPG’s key components ultimately alleviate bronchitis symptoms. Modulation of these three pathways by compounds targeting PTGS2, AKT1, and TNF offers a coherent mechanistic account of how a single herbal formula can simultaneously reduce inflammatory signaling, promote mucus clearance, and suppress the cough reflex.

The study, received in April 2026 and published open access on 8 October 2026, represents a methodological template as much as a single result: validate efficacy in animals, quantify inflammation in vivo and in vitro, then use network pharmacology and docking to explain the mechanism. The authors, led by corresponding author Wendong Li of the Beijing Institute for Drug Control, declare no competing interests. For a field often criticized for offering traditional remedies without mechanistic justification, the work shows how modern computational tools can dissect a multi-component formula into its active ingredients and target pathways, potentially guiding more precise clinical use of ZPG and informing the design of new combination therapies for inflammatory airway disease.

Subject of Research: Mechanism of Zhike Pipa Granules in treating bronchitis via network pharmacology, molecular docking, and experimental validation

Article Title: Exploring the effects and mechanisms of zike pipa granules in treating bronchitis based on network pharmacology, molecular docking and experimental validation

Article References: Qu, S., Zhou, J., Gao, Y., Li, F., Li, Z., Chen, S., Cao, C., & Li, W. (2026). Exploring the effects and mechanisms of zike pipa granules in treating bronchitis based on network pharmacology, molecular docking and experimental validation. BMC Complementary Medicine and Therapies. https://doi.org/10.1186/s12906-026-05609-7

Image Credits: AI Generated

DOI: 10.1186/s12906-026-05609-7

Keywords: Zhike Pipa Granules, bronchitis, network pharmacology, molecular docking, quercetin, EGCG, kaempferol, PTGS2, AKT1, TNF, traditional Chinese medicine, inflammation