Background/Objectives: The inflammatory response has evolved as a protective mechanism against pathogens and tissue damage. However, chronic inflammation can occur, potentially leading to severe disease. Low-grade chronic inflammation is associated with obesity, and the Th1 cytokine profile plays an important role in this proinflammatory environment. Diet-induced obesity (DIO) can lead to persistent dysbiosis and maintain high concentrations of circulating lipopolysaccharides (LPSs) over prolonged periods of time, resulting in metabolic endotoxemia. In this context, the study of natural immunomodulators has recently increased. Objective: The aim of this study is improve scientific evidence for the immunomodulatory role of L-Alliin in obesity and inflammation. Methods: In the present work, we describe the effect of L-Alliin on serum levels of cytokines in DIO mice after an acute inflammatory challenge. L-Alliin is the main organosulfurized molecule of garlic that has been studied for its numerous beneficial physiological effects in health and disease and is beginning to be considered a nutraceutical. Two situations are simulated in this experimental model, health and chronic, low-grade inflammation that occurs in obesity, both of which are confronted with an acute, inflammation-inducing challenge. Results: Based on our findings, L-Alliin seems to somehow stimulate the cellular chemotaxis by eliciting the release of key molecules, including IL-2, IFN-γ, TNF-α, MCP-1, IL-6, IL-9, and G-CSF. However, the molecular mechanism involved remains unknown. This, in turn, mitigates the risk of severe inflammatory symptoms by preventing the release of IL-1β and its downstream molecules such as IL-1α, GM-CSF, and RANTES. Conclusions: Taken together, these results indicate that L-Alliin can boost immunity in healthy organisms and act as an immunomodulator in low-grade inflammation.

Background/Objectives: A high-fat diet disrupts metabolic and neuroimmune balance in the brain, making neural tissue more reactive to inflammatory challenges. However, it is not well understood how this vulnerability varies across brain regions or how natural anti-inflammatory compounds influence it. Methods: In this study, we examined how the garlic-derived molecule L-alliin modulates the inflammatory response triggered by lipopolysaccharide in the frontal cortex, hippocampus, and hypothalamus of mice fed either a standard or high-fat diet. Results: Measurements of cytokine gene expression showed that the high-fat diet greatly increased the inflammatory response in the frontal cortex and hypothalamus, with the hypothalamus displaying the strongest overall activation. Treatment with L-alliin significantly reduced elevated cytokine levels in both regions, with the reductions most pronounced in animals on the high-fat diet. In contrast, the hippocampus showed a distinct pattern: expression of TNF-α and IL-1β changed very little across diets or treatments, whereas IL-6 and CCL2 were selectively altered by L-alliin, depending on the animals’ metabolic state. Conclusions: These findings demonstrate that diet-induced obesity does not affect the entire brain uniformly. Instead, inflammatory pathways are altered region-specifically, and L-alliin modulates these pathways with sensitivity to both brain region and metabolic condition. This work emphasizes the importance of accounting for neuroanatomical differences when developing strategies to reduce inflammation in obesity-associated conditions.

Background: Garlic has been considered to have medicinal properties in different cultures since ancient times. Vegetables of the allium genus are a natural source of sulfur-containing organic compounds. These compounds have recently been investigated for their positive health effects, such as antioxidant and anti-inflammatory, as well as cardioprotective and anticarcinogenic properties. Objective: In this review, we focus on one of the main components of garlic; alliin or S-allyl-Lcysteine sulfoxide, which is a non-protein amino acid that exhibits a broad spectrum of beneficial effects on physiology, both at the cellular and whole organism levels. Methods: We conducted a systematic literature search of the MEDLINE (PubMed) database. Search terms used for alliin were: “S-allylcysteine sulfoxide” OR “L-alliin” OR “ACSO”, all of them combined into a separated search term individually as follows: AND “antioxidant”; AND “cardioprotective”; AND “anti-inflammatory”; AND “antimicrobial”; AND “disease”, and; AND “neuroprotective”. Results: Here, we review and integrate the existing experimental evidence on the effects of alliin, mainly on its antioxidant and anti-inflammatory effects, as well as its cardioprotective action, and its role as an adjuvant for the treatment of different diseases, such as infectious diseases, inflammatory diseases, metabolic diseases and cancer. Conclusion: Finally, we propose alliin as a possible neuroprotective agent, through the combination of its antioxidant and anti-inflammatory effects, and its ability to reduce markers of metabolic inflammation in obesity.