This study was conducted to analyze the effect of curcumin on levels of NF-kB, TNF-a, and pain intensity after high-intensity physical exercise..
We observed that the placebo group did not significantly decrease NF-kB, TNF-a levels and pain intensity after high-intensity physical exercise, while the 400 mg curcumin group significantly reduced NF-kB, TNF-a levels, and pain intensity. painful. Our research answer and confirm a literature study reported findings that curcumin has a positive effect on inflammatory responses [16], [26]. High-intensity physical exercise, especially with eccentric movements, will result in muscle damage and inflammatory response [27], [28].. Eccentric movements contribute to high mechanical stress and produce bone extracellular matrix fragments that are recognized by receptors expressed by innate immune cells [27]. Cell activation mediated by this process stimulates NF-kB activation [29].
A theory reports that NF-kB plays a role in controlling inflammation, especially in the secretion of pro-inflammatory cytokines such as TNF-a and IL-6 [27]. In this regard, we believe that the main cause of muscle pain is due to an uncontrolled increase in pro-inflammatory cytokines such as TNF-a for several days after high-intensity physical exercise. In the case of exercise-induced muscle damage, a histological study showed that neutrophils enter the muscles and accumulate in the damaged area from 1 to 24 hours after exercise [30]. In addition, muscle damage is characterized by ultrastructural disturbances of the muscles which increase the release of inflammatory cytokines by macrophages [27]. Neutrophils and pro-inflammatory cytokines that interact with each other aim to control the pro-inflammatory response when muscle damage occurs [31]. On the other hand, while pro-inflammatory cytokines increase, macrophages also release anti-inflammatory cytokines that contribute to muscle recovery and regeneration [32].
We believe the role of NF-kB is the therapeutic goal of curcumin in inflammation because of the importance of NF-kB in the regulation and expression of TNF-a which is a cause of muscle pain. Our research findings are supported by an experimental study on the effect of curcumin on NF-kB expression in rats induced by drinking ethanol (Fatolahi et al. 2020). In that study, curcumin can significantly reduce NF-kB levels. In addition, a study reported that curcumin is able to attenuate osteoarthritis through the NF-kB pathway [33]. Curcumin is one of the natural ingredients that have anti-inflammatory activity [26], [34]. A recent literature study reported that curcumin works by suppressing the secretion of pro-inflammatory cytokines such as IL-1, IL-6, IL-8, IL-17, and TNF-a [35]. Research on the effect of curcumin on TNF-a levels after exercise is perhaps limited. However, on the other hand, we found a study that reported that there was no significant reduction in TNF-a levels given curcumin at a dose of 1500 mg/day for 28 days after aerobic exercise in trained men [36]. We analyzed from this study that the ineffective effect of curcumin is probably due to aerobic exercise which is classified as moderate exercise intensity so it does not trigger post-exercise inflammation. In this regard, what distinguishes this research is that the subjects involved are people who are not trained and the exercises are carried out with high intensity. This is a strong foundation that physical exercise performed at high-intensity results in muscle damage and triggers an increase in pro-inflammatory cytokines such as TNF-a and IL-6 in the blood [16], [26]. On the other hand, at the right levels, TNF-a will provide protection and healing, but at excessive levels, TNF-a will cause tissue damage and trigger muscle pain [11].
In summary, interesting new findings in this study reported that curcumin given at a dose of 400 mg/day was able to reduce NF-kB levels, TNF-a, and pain intensity after high-intensity physical exercise. Based on laboratory tests that we have done, we believe the reduction in pain intensity occurs due to the anti-inflammatory effect of curcumin which is able to modulate NF-kB signals and blockade TNF-a signals. Meanwhile, we carefully all aspects of research and measurement during the research. We believe that the strengths of these findings outweigh our shortcomings in the study. In future studies, we hope to examine the effects of curcumin on other inflammatory biomarkers.