Allicin

Allicin is a biologically active sulfur compound found primarily in fresh garlic (Allium sativum). It is formed through an enzymatic reaction as soon as garlic cloves are chopped or crushed – in this process, the inactive alliin is converted into allicin by the enzyme alliinase. The characteristic smell of fresh garlic is largely due to this substance. Allicin is the subject of intensive scientific research, as it shows a wide range of health-promoting effects – including antibacterial, antiviral, antifungal, anti-inflammatory, and antioxidant effects. Particularly exciting is the potential of allicin in the area of cardiovascular health, in infections, and for immune support. In natural medicine, it has been used for centuries as a universal remedy.

What health benefits are attributed to allicin?

Allicin is an active compound that enjoys lively attention in studies. The results of these studies suggest various effects originating from the compound. The potential effects are listed below. However, the results of the studies are not readily transferable, and more research is needed to fully understand the effects.

  • Antimicrobial effects: Allicin inhibits a wide range of bacteria, viruses, and fungi, including Staphylococcus aureus, Candida albicans, and influenza viruses. It is considered a natural broad-spectrum antibiotic (1,2).
  • Cardiovascular protection: Allicin can lower blood pressure, inhibit blood clotting, and improve the elasticity of the blood vessels – important protective factors against heart attack and stroke (3,4,5).
  • Anti-inflammatory and antioxidant cell protection: It reduces the formation of free radicals and blocks pro-inflammatory signaling pathways such as NF-κB, which is of importance in chronic inflammatory diseases (3,5,6,7).
  • Immunomodulation: Allicin supports the immune system by promoting the activity of macrophages, T cells, and natural killer cells (7).
  • Cholesterol reduction: Studies suggest that allicin can lower LDL levels while promoting HDL, which contributes to the prevention of arteriosclerosis (1,8).

How does allicin work in the body?

The effect of allicin appears to be attributable to various mechanisms. Reactive sulfur groups in allicin can react with proteins and enzymes of pathogenic microorganisms and inactivate them. The substance acts as a radical scavenger, meaning it can neutralize free radicals and thus reduce oxidative stress in cells. It also appears that allicin modulates genes involved in inflammation, cell protection, and immune response. However, allicin is not very stable – it breaks down relatively quickly and is therefore only present in high amounts immediately after fresh garlic is chopped (1,9).

Side effects and risks

  • Gastrointestinal complaints: In sensitive individuals or at high doses, nausea, heartburn, or bloating may occur.
  • Odor formation: The typical garlic smell can be released through the breath and skin.
  • Blood thinning: Allicin has an anticoagulant effect – people who take blood thinners or are about to undergo surgery should be careful.
  • Allergic reactions: In rare cases, garlic can trigger contact dermatitis or other hypersensitivities.

Conclusion

Allicin is an impressive natural compound with strong medicinal potential. It has antimicrobial, anti-inflammatory, antioxidant, and vascular-protective effects. It offers a variety of benefits, particularly for the cardiovascular system and the immune defense. However, since it is sensitive to heat and processing, consuming fresh, raw garlic is recommended in order to benefit from its full spectrum of effects. Therapeutic use should take place in consultation with qualified professionals.

Sources:

  1. Salehi, B., Zucca, P., Orhan, I. E., Azzini, E., Adetunji, C. O., Mohammed, S. A., Banerjee, S. K., Sharopov, F., Rigano, D., Sharifi-Rad, J., Armstrong, L., Martorell, M., Sureda, A., Martins, N., Selamoğlu, Z., & Ahmad, Z. (2019). Allicin and health: A comprehensive review. Trends in Food Science & Technology, 86, 502–516. https://doi.org/10.1016/j.tifs.2019.03.003
  2. Borlinghaus, J., Albrecht, F., Gruhlke, M. C., Nwachukwu, I. D., & Slusarenko, A. J. (2014). Allicin: chemistry and biological properties. Molecules (Basel, Switzerland), 19(8), 12591–12618. https://doi.org/10.3390/molecules190812591
  3. García-Trejo, E. M., Arellano-Buendía, A. S., Argüello-García, R., Loredo-Mendoza, M. L., García-Arroyo, F. E., Arellano-Mendoza, M. G., Castillo-Hernández, M. C., Guevara-Balcázar, G., Tapia, E., Sánchez-Lozada, L. G., & Osorio-Alonso, H. (2016). Effects of Allicin on Hypertension and Cardiac Function in Chronic Kidney Disease. Oxidative medicine and cellular longevity, 2016, 3850402. https://doi.org/10.1155/2016/3850402
  4. Wang, H. P., Yang, J., Qin, L. Q., & Yang, X. J. (2015). Effect of garlic on blood pressure: a meta-analysis. Journal of clinical hypertension (Greenwich, Conn.), 17(3), 223–231. https://doi.org/10.1111/jch.12473
  5. Gao, Y., Wang, B., Qin, G. et al. Therapeutic potentials of allicin in cardiovascular disease: advances and future directions. Chin Med 19, 93 (2024). https://doi.org/10.1186/s13020-024-00936-8
  6. Sánchez-Gloria, J. L., Arellano-Buendía, A. S., Juárez-Rojas, J. G., García-Arroyo, F. E., Argüello-García, R., Sánchez-Muñoz, F., Sánchez-Lozada, L. G., & Osorio-Alonso, H. (2022). Cellular Mechanisms Underlying the Cardioprotective Role of Allicin on Cardiovascular Diseases. International Journal of Molecular Sciences, 23(16), 9082. https://doi.org/10.3390/ijms23169082
  7. Arellano Buendía, A. S., Tostado González, M., Sánchez Reyes, O., García Arroyo, F. E., Argüello García, R., Tapia, E., Sánchez Lozada, L. G., & Osorio Alonso, H. (2018). Immunomodulatory Effects of the Nutraceutical Garlic Derivative Allicin in the Progression of Diabetic Nephropathy. International journal of molecular sciences, 19(10), 3107. https://doi.org/10.3390/ijms19103107
  8. Nadeem, M. S., Kazmi, I., Ullah, I., Muhammad, K., & Anwar, F. (2021). Allicin, an Antioxidant and Neuroprotective Agent, Ameliorates Cognitive Impairment. Antioxidants (Basel, Switzerland), 11(1), 87. https://doi.org/10.3390/antiox11010087
  9. Savairam, V. D., Patil, N. A., Borate, S. R., Ghaisas, M. M., & Shete, R. V. (2023). Allicin: A review of its important pharmacological activities. Pharmacological Research - Modern Chinese Medicine, 8, 100283. https://doi.org/10.1016/j.prmcm.2023.100283