The human body possesses a variety of defense mechanisms against pathogens and foreign substances. However, the digestive system remains vulnerable as it serves as a primary point of entry for harmful microbes, particularly those found in contaminated food and various environments. The digestive system acts as the first line of defense, utilizing stomach acid and mucus secretions containing antibodies to neutralize and eliminate these threats. Nevertheless, certain pathogens can evade these defensive measures, leading to infections within the digestive tract. In Thailand, common gastrointestinal pathogens include Staphylococcus aureus, Clostridium perfringens, Clostridium botulinum, Shigella spp., Salmonella Typhimurium, Salmonella Typhi, Campylobacter jejuni, Listeria monocytogenes, Campylobacter coli, and pathogenic strains of Escherichia coli. (Echeverria et al., 2006) Infections caused by these pathogens and their toxins significantly contribute to the induction of inflammation in the intestinal lining.

Inflammation plays a crucial role in the immune system's response to injury, enabling immune cells to eliminate foreign substances and prevent infection or further harm. Once the foreign substance is eradicated, inflammation subsides, initiating the healing process. Macrophages are essential for regulating and maintaining tissue balance during this process. However, dysfunctional macrophages can result in persistent inflammation, hindering wound healing and tissue repair. Consequently, chronic infection and inflammatory tissue diseases can develop. Additionally, chronic inflammation can contribute to the formation of granulomas, atherosclerosis, metabolic syndrome, and even promote cancer development (Murray and Wynn, 2011).

The behavior and function of macrophages are influenced by various factors, including their interaction with microorganisms. This intricate and specific process depends on the type of microorganism and the tissue environment. Microbial metabolites can potentially affect macrophage gene expression at different levels (Lavin et al., 2015). When macrophages become abnormal, persistent inflammation can disrupt the digestive system's gut microbiome. This disruption, known as gut microbiota dysbiosis, can result in an increase in harmful microorganisms and a decrease in beneficial bacteria. This imbalance further stimulates macrophages, perpetuating a cycle of chronic inflammation and infection. In some patients, abnormal growth of adherent-invasive E. coli (AIEC) has been observed, which is associated with Inflammatory Bowel Disease (IBD) such as Crohn's disease and ulcerative colitis (Nadalian et al., 2021). Furthermore, inappropriate use of antibiotics for gastrointestinal infections can lead to antibiotic resistance in microorganisms, resulting in gut microbiota dysbiosis and ongoing inflammation of the intestinal lining.

Plants have a lengthy historical record of being utilized for the discovery and development of active compounds and medicines aimed at treating and alleviating adverse symptoms. Herbal medicines are recognized for their many active components, which empower them to promote health via various mechanisms. One such mechanism involves the regulation of macrophage metabolism and gene expression, ultimately resulting in the hindrance of energy production and bacterial cell division.

This study aims to explore the impact of herbal extracts on macrophage protein secretion in response to inflammatory stimuli caused by bacterial infections. Moreover, the study seeks to evaluate the inhibitory properties of these herbs on the proliferation of gastrointestinal pathogens. Specifically, the focus is on three commonly encountered herbs in Thailand: Thunbergia laurifolia Lindl. (a member of the Acanthaceae family), Phyllanthus amarus Schum & Thonn. (a member of the Euphorbiaceae family), and Moringa oleifera Lam. (a member of the Moringaceae family). These three herbs have long been recognized for their beneficial effects on the digestive system in traditional Thai medicine. They are frequently incorporated into food preparations or brewed into herbal teas. The findings of this study will provide valuable insights for developing innovative immunometabolic modulatory drugs, thus offering alternative therapeutic options for emerging infectious diseases or infections resistant to approved treatments. Additionally, these results have the potential to enhance the market value of herbal products, allowing businesses to utilize the research data to promote the use of herbs in the context of preventive healthcare.