Immunomodulation and Anti-Inflammatory Effects of Garlic Compounds
Table 2
Immunoregulatory properties of garlic.
Immunoregulatory mechanism
Model/pathology involved
Garlic preparation (dose)
Immunoparameters evaluated
Conclusions
References
3T3-L1 adipocytes stimulated with LPS/in vitro model of inflamed adipose tissue.
Cell incubation with alliin for 24 h (100 mol/L).
Proinflammatory cytokines and adipocytokines IL-6, TNF-α, MCP-1, and adiponectin.
Alliin is capable of suppressing LPS inflammatory signals by generating an anti-inflammatory gene expression and prevented the increase in expression of proinflammatory cytokines IL-6 and MCP-1.
Cellularity of cervical lymph nodes. Production of Th1 cytokines IL-2 and IFN-γ and Th2-type cytokines IL-4 and IL-10.
Garlic oil enhances and shifts toward Th1-type response at low doses. It promotes an anti-inflammatory environment at high doses by shifting Th1-Th2 balance toward the Th2 type.
Preeclamptic placental explant tissue stimulated with LPS.
Garlic extract (10, 100, 500, and 1,000 g/mL).
Cytokine levels of TNF-α, IL-6, IL-10, and sTRAIL.
Garlic at lower doses possesses an immunomodulatory effect on normal placenta by increasing production of IL-10 and in preeclamptic explants reduces production of inflammatory cytokines such as IL-6 and TNF-. At higher doses, overall effect is one of cytokine synthesis inhibition and stimulation of sTRAIL production.
Balb/c mice infected with Plasmodium yoelii/Malaria.
Allicin orally applied 3 or 9 mg/kg/day on days 0–2 (PI).
Pro- and anti-inflammatory cytokines IFN-, TNF-, IL-12p70, IL-4, and IL-10.
Allicin reduced parasitemia and prolonged survival due to improved host immune responses. Enhancement of proinflammatory mediators IFN-, TNF-, and IL-12p70. No changes in anti-inflammatory cytokines IL-4 and IL-10.
In vitro assays: neutrophil-like cells (HL-60 cell line).
Garlic oil (1 μg/mL < 10 μg/mL) for 60 min.
Chemotactic responsiveness and motility of neutrophil-like cells.
Average migration speed of cells reduced after being treated with garlic oil, thereby resulting in anti-inflammatory activities through inhibition of assembly and disassembly of cytoskeleton inside the cell.
Activation of humoral immune response and synthesis of Ig
In vivo assays, white Leghorn chickens/viral and bacterial infection.
Dietary alliums: Allium sativum (G) and Allium cepa (O) (low doses: 10 g/kg (GL and OL) or high doses 30 g/kg (GH and OH)).
Antibodies, lymphocyte proliferation, and ratios of CD4+ : CD8+ and CD4− : CD8− lymphocytes.
GL and OL enhanced anti-NDV, anti-SRBC, and anti-BA antibody productions. Only GL- and GH had a comitogenic effect on splenocytes and thymocytes. Reduction in CD4+ and increase in CD4− : CD8− lymphocyte ratios were observed with GH or OH.
In vitro assays: RBL-2H3 induced by (TNP) monoclonal antibody and the TNP (BSA-related) hapten carrier complex/allergic reactions. In vivo assays: Balb/c male mice i.v. administered anti-TNP IgE antibody and subsequent picryl chloride painting on the ear/allergic reactions.
AGE incubation (1.25, 2.5, and 5.0 g/100 g). AGE orally applied (10 mL/kg).
Histamine release by basophils. Ear swelling used as an index of immunoglobulin IgE-mediated skin reaction.
AGE significantly inhibited antigen- specific histamine release and decreased ear swelling. AGE may directly and/or indirectly modify functions of mast cells, basophils, and activated T lymphocytes, which play a leading role in allergic cascade reactions.
3 IP injections of 14 kD fraction of AGE (20 mg/kg).
Percentages of lavage eosinophils. Mucus-producing goblet cells in airways. Perivascular and peribronchial inflammatory grades.
14 kD fraction of AGE is able to reduce allergic-airway inflammation hallmarks in murine model accompanied by increase in IFN--level bronchoalveolar lavage.
Proliferation index in murine splenocytes/thymocytes and human PBL.
All three proteins exhibited mitogenic activity toward human PBL and murine splenocytes/thymocytes. Mitogenicity of QR-2 was the highest among the three immunomodulatory proteins.
Alliin induces PWM-cell proliferation, spontaneous production of IL-1, as well as an increase in number of phagocyting cells and engulfed latex particles. Alliin causes decrease in mitogenic function of ConA.
