The anti-inflammatory effect of Citrus Bioflavonoids is not a single fixed effect, and its intensity and specificity are affected by a variety of factors, which include the physicochemical properties of Citrus Bioflavonoids itself, but also involves the extraction and preparation process, the state of the body and the inflammatory environment, etc., specifically as follows:
1. Composition and proportion of its own components
Citrus Bioflavonoids is a class of mixtures mainly containing hesperidin, neohesperidin, naringenin, naringenin, naringenin, etc., etc. Flavonoids, there are differences in the anti-inflammatory activity of different components, and the ratio between the components will directly affect the overall anti-inflammatory effect.
2. Dosage and mode of administration
The anti-inflammatory effect of Citrus Bioflavonoids has a dose-dependence and administration route specificity:
Dosage effect: within a certain range, the anti-inflammatory effect is enhanced with the increase of dose (e.g., the inhibition of NF-κB activation and the reduction of IL-6 secretion are more significant); however, after exceeding the threshold, the anti-inflammatory effect may be due to “hormesis effect However, after exceeding the threshold, the anti-inflammatory effect may be weakened due to “hormesis effect” (promoted by low dose and inhibited by high dose) or cytotoxicity, and even oxidative stress or immune disorder may be induced. For example, in vitro experiments showed that the inhibition of macrophage inflammation by Citrus Bioflavonoids total flavonoids at 50-200 μg/mL increased with the dose, but more than 400 μg/mL led to a decrease in cell survival and a weakening of the anti-inflammatory effect.
Mode of administration: Oral administration requires gastrointestinal metabolism (e.g., intestinal flora transformation, hepatic first-pass effect), which may affect bioavailability (e.g., hesperidin needs to be hydrolyzed to hesperidin by intestinal flora to be better absorbed); intraperitoneal injection or intravenous administration can directly enter the circulatory system, which has a quicker onset of action, but may increase the burden of metabolism on the liver and kidneys. Differences in body exposure due to different modes of administration will directly affect the strength and duration of the anti-inflammatory effect.
3. Types and pathological mechanisms of inflammation models
The anti-inflammatory effects of Citrus Bioflavonoids are tissue/disease specific, and their effects are closely related to the triggering factors and target pathways of inflammation:
For infectious inflammation (e.g., LPS-induced sepsis), Citrus Bioflavonoids can reduce the release of pro-inflammatory factors (TNF-α, IL-6) mainly through the inhibition of the NF-κB and MAPK pathways;
For autoimmune inflammation (e.g., rheumatoid arthritis), the effects of Citrus Bioflavonoids can be directly affected by the effects of the anti-inflammatory drugs in the body. For autoimmune inflammation (e.g., rheumatoid arthritis), it tends to inhibit the activity of COX-2 and iNOS, reduce mediators such as PGE₂ and NO, and modulate immune cell (e.g., T cell, macrophage) infiltration.
For metabolic inflammation (e.g., obesity-associated inflammation in adipose tissues), it may play a role in improving insulin resistance, and inhibiting the inflammatory factors secreted by adipocytes (e.g., resistin, leptin).
Therefore, in different inflammation models, Citrus Bioflavonoids’ intensity of action and dominant targets differ, and their anti-inflammatory effects need to be evaluated in the context of specific diseases.
4. Physiological state and individual differences
Individual differences in metabolic ability, intestinal flora and genetic background may affect the anti-inflammatory effect of Citrus Bioflavonoids:
Intestinal flora: The glycoside components (such as hesperidin) in Citrus Bioflavonoids need to be hydrolyzed by the β-glucosidase of intestinal flora into the glycosides (hesperidin) to be absorbed, and the dysbiosis of the intestinal flora (e.g., lack of a specific bacterial genus) may result in a decrease in the efficiency of biotransformation and reduce the anti-inflammatory activity; on the contrary, it is necessary to evaluate its anti-inflammatory effect in the context of specific diseases. If the intestinal flora is dysbiotic (e.g. lack of a specific genus of bacteria), it may lead to a decrease in the efficiency of biotransformation and anti-inflammatory activity; on the contrary, individuals with a healthy intestinal flora may be more likely to exert its effects.
Liver and kidney function: Flavonoids are mainly metabolized by the liver (e.g. glucuronidation) and excreted by the kidneys. Hepatic and renal insufficiency may lead to the accumulation of metabolites, which may affect the persistence of anti-inflammatory effects and even increase the risk of adverse reactions.
Gene polymorphisms: polymorphisms in inflammation-related genes (e.g. NF-κB p65. IL-6 promoter) may affect the sensitivity of targets to Citrus Bioflavonoids, e.g., individuals carrying specific genotypes are more sensitive to NF-κB inhibition and have more significant anti-inflammatory effects.