As stated in the first part of our mini-series, also external factors – such as a dietary uptake of selected substances – are able to modulate various factors of immune response. Find out in this second part, how phytogenics help with their anti-inflammatory and immunomodulating effects.
In recent decades…
…global research on phytogenic feed additives become more intense. Phytogenic substances, such as flavonoids, polysaccharides, lactones, alkaloids, diterpenoids and glycosides, are also referred to as “secondary plant substances”.
Did you know?
Secondary plant compounds represent substances produced by a plant in relatively small amounts and are related to survival strategies: they are used by plants to prevent overgrowth with pest plants or attaching with pest insects or fungi, to prevent some parasites, or to attract pollinators via producing a certain smell or causing a typical color of the plant. Thus, although they are not directly needed for the survival of the organism, secondary plant substances can have crucial impact on the lifespan of a plant. When taken up by humans or livestock, these secondary plant substances may influence the physiology and can unroll pharmacological effects.
Ever heard about the gene regulatory effects of phytogenics?
In context with research for alternatives to antibiotic growth promoters, the investigation of the mode of action of these phytogenic substances revealed their potency also in gene regulation via modulation of transcriptional factors. Numerous studies show, that metabolites of plants like garlic, black pepper, curcuma, hop or aloe have anti-inflammatory properties. Those anti-inflammatory properties are induced due to the down-regulation of NF-κB expression and other pro-inflammatory mediators like interleukin 1 (IL-1), mainly produced by activated mononuclear phagocytes. Both, the alpha- and beta-form of IL-1, induce endothelial cell adhesion molecules, stimulate chemokine production by endothelial cells as well as macrophages and activate acute-phase reactants by the liver.
Fight against pro-inflammatory mediators – with the pure power of plants.
Furthermore, the transcription factor NF-κB also triggers genes causing an upregulated expression of intracellular and vascular adhesion molecules as well as enzymes relevant for several oxidative processes.
Bio-actives, which can be found in other plants, like sorrel, olive or Japanese knotweed, have been proven to downregulate Interferon-γ, a cytokine produced by T-lymphocytes as well as natural killers cells, whose principal function is to activate macrophages – in both innate immune response and in adaptive cell-mediated immune response.
Did you know?
Also anti-oxidant effects of phytogenic substances impact anti-inflammatory processes, since oxidative and metabolic stressors will trigger the NF-κB pathway which further results in the production of reactive oxygen species helping macrophages fight against bacterial infections.
Selected phytogenics are able to bind to an adapter protein called Keap1, which under unstressed conditions forms a complex with the redox sensitive transcription factor Nrf2. If a phytogenic compound binds to Keap1, Nrf2 is released and translocates from cytoplasma to the nucleus, where it will activate the transcription of various antioxidant enzymes, resulting in a diminished risk to promote inflammatory processes.
Let’s sum up
Plant-derived bio-active substances may modulate the NF-κB-pathway as well as the Nrf2-pathway and thus, are able to balance complex processes of inflammation and the oxidative status of individual animals.
A down-regulation of pro-inflammatory genes in the intestinal tissues can increase feed efficiency and growth performance of livestock animals.
Hence, anti-inflammatory and immunomodulating effects of selected phytogenic compounds have the potential to contribute to profitable livestock farming and to increase animal welfare.
References available upon request
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