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.

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1. Diallyl disulphide (DADS), a compound formed from the organosulphur compounds present in garlic, is known for its anticarcinogenic effects in animal models. 2. The aim was to identify and analyse the metabolites produced in vivo after a single oral administration of 200 mg kg(-1) DADS to rats. The organic sulphur metabolites present in the stomach, liver, plasma and urine were measured by gas chromatography coupled with mass spectrometry over 15 days. 3. Data indicate that DADS is absorbed and transformed into allyl mercaptan, allyl methyl sulphide, allyl methyl sulphoxide (AMSO) and allyl methyl sulphone (AMSO(2)), which are detected throughout the excretion period. Overall, the highest amounts of metabolites were measured 48-72h after the DADS administration. AMSO(2) is the most abundant and persistent of these compounds. The levels of all the sulphur compounds rapidly decline within the first week after administration and disappear during the second week. Only AMSO and AMSO(2) are significantly excreted in urine. 4. These potential metabolites are thought to be active in the target tissues. Our data warrant further studies to check this hypothesis.

Dimethyl disulfide (DMDS) was identified as a major volatile constituent of Brassica napus roots heavily infested by Delia radicum, the cabbage root fly. Attractiveness of this widespread compound was tested in the field in a naturally complex odorous environment. By using an original setup especially designed for ground dwelling beetles, different concentrations of the pure molecule as well as attractiveness of the natural blend emitted by the rotten part of infested roots were tested simultaneously. The use of general linear model (GLM) statistics permitted us to finely discriminate the responses among the different treatments. The main predators of D. radicum (i.e., two staphylinids Aleochara bilineata and Aleochara bipustulata and carabid beetles of the genus Bembidion) were significantly attracted by DMDS, but responded in different ways to the natural blend and to the different concentrations tested. The dose-response curves were similar for the two staphylinids. However, whereas A. bilineata was more attracted by the natural volatile blend than by its preferred DMDS concentration, A. bipustulata was attracted as much by the natural blend as by its preferred DMDS concentration. Carabid beetles exhibited a different response. They were not attracted by the natural blend, but responded to a wider range of DMDS concentrations that included low concentrations that did not attract the staphylinid beetles. These results are discussed according to the potential resources searched by each taxon studied and their specificity for the resources. The possible use of DMDS for enhancing biological control of D. radicum is mentioned.

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Abstract. Extending the collection of garlic (Allium sativum L.) accessions is an important means that is available for broadening the genetic variability of this cultivated plant, with regard to yield, quality, and tolerance to biotic and abiotic traits; it is also an important means for restoring fertility and flowering. In the framework of the EU project 'Garlic and Health', 120 garlic accessions were collected in Central Asia -the main centre of garlic diversity. Plants were documented and thereafter maintained in field collections in both Israel and The Netherlands. The collection was evaluated for biological and economic traits. Garlic clones vary in most vegetative characteristics (leaf number, bulb size and structure), as well as in floral scape elongation and inflorescence development. A clear distinction was made between incomplete bolting and bolting populations; most of the accessions in the latter populations produced flowers with fertile pollen and receptive stigma. Wide variations were recorded with regard to differentiation of topsets, their size, number and rapidity of development. Furthermore, significant variation in organo-sulphur compounds (alliin, isoalliin, allicin and related dipeptides) was found within garlic collections and between plants grown under differing environmental conditions. Genetic fingerprinting by means of AFLP markers revealed three distinct groups within this collection, differing also in flowering ability and organo-S content.Abbreviations: AFLP TM -amplified fragment length polymorphism; HPLC-UV -high performance liquid chromatography ultra violet; PCA -principal component analysis;