Garlic is proposed to have immunomodulatory and anti-inflammatory properties. This paper shows that garlic powder extracts (GPE) and single garlic metabolites modulate lipopolysaccharide (LPS)-induced cytokine levels in human whole blood. GPE-altered cytokine levels in human blood sample supernatants reduced nuclear factor (NF)-kappaB activity in human cells exposed to these samples. Pretreatment with GPE (100 mg/L) reduced LPS-induced production of proinflammatory cytokines interleukin (IL)-1beta from 15.7 +/- 5.1 to 6.2 +/- 1.2 micro g/L and tumor necrosis factor (TNF)-alpha from 8.8 +/- 2.4 to 3.9 +/- 0.8 micro g/L, respectively, whereas the expression of the anti-inflammatory cytokine IL-10 was unchanged. The garlic metabolite diallydisulfide (1-100 micro mol/L) also significantly reduced IL-1beta and TNF-alpha. Interestingly, exposure of human embryonic kidney cell line (HEK293) cells to GPE-treated blood sample supernatants (10 or 100 mg/L) reduced NF-kappaB activity compared with cells exposed to untreated blood supernatants as measured by a NF-kappaB-driven luciferase reporter gene assay. Blood samples treated with extract obtained from unfertilized garlic (100 mg/L) reduced NF-kappaB activity by 25%, whereas blood samples treated with sulfur-fertilized garlic extracts (100 mg/L) lowered NF-kappaB activity by 41%. In summary, garlic may indeed promote an anti-inflammatory environment by cytokine modulation in human blood that leads to an overall inhibition of NF-kappaB activity in the surrounding tissue.

Addition of [9,10-2H2]oleic acid to cultures of the yeast Sporobolomyces odorus led to the formation of labeled (R)-γ-decanolactone and both enantiomers of (Z)-6-γ-dodecenolactone and γ-dodecanolactone. The labeling patterns of these lactones were estimated by a quantitative gas chromatography/mass spectrometry method, suitable for ring-labeled lactones. For the first time, there is strong evidence of oleic acid being a genuine precursor of the important aroma compound (R)-γ-decanolactone. On the basis of the presented and former results, a new biosynthetic pathway of this compound is proposed. Starting with a strict enantioselective (R)-12-hydroxylation of oleic acid as an initial step, the following β-oxidation led to the lactone. In addition, biosynthetic aspects of the formation of (Z)-6-γ-dodecenolactone and γ-dodecanolactone in S. odorus are discussed. Keywords: γ-Lactones; aroma compound; (R)-γ-decanolactone; [9,10-2H2]oleic acid; Sporobolomyces odorus; biosynthesis

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We conclude that a chemically well-characterized garlic preparation has no significant effect on inflammatory biomarkers, endothelial function, or lipid profile in normolipidemic subjects with risk factors for CVD.