Protective role of natural products in pulmonary fibrosis through immune regulation

Caused by respiratory diseases, pulmonary fibrosis (PF) is a deadly fibrotic illness that progresses over time. It can eventually result in serious organ failure and death and is closely linked to several risk factors. There has been a growing interest in the immune system's involvement in PF, with various immune factors participating in the inflammation and fibrosis processes. Different immune cell types, including neutrophils, lymphocytes, and macrophages, have varying effects on the development and course of PF. Additionally, key cytokines in the immune system, such as the interleukin family, tumor necrosis factor (TNF) -α, interferon (IFN)-γ, transforming growth factor (TGF)-β, and connective tissue growth factor (CTGF), play a part in the emergence and advancement of PF, each with independent mechanisms and mutual regulation. There are currently very few effective treatments for PF, and there are several severe medication reactions. Natural products, known for their multi-target, holistic regulation, and low toxicity, have turned into a topic of study. The mechanisms, therapeutic potential, and active ingredients of several natural products are compiled in this review. These substances can mitigate lung inflammation, epithelial-mesenchymal transition, and collagen deposition through different immune mechanisms, acting at various stages of fibrosis or throughout the entire process, hence supporting the management of PF. The current state of science on natural products' effects on the immune system in PF is reviewed in this review, which is important for the development of future anti-PF medications.