Diallyl disulphide, but not diallyl sulphide, increases leucocyte function-associated antigen-1 expression and cellular adhesion in monocytes

Organosulfide profile and hydrogen sulfide-releasing capacity of stinky bean (Parkia speciosa) oil: Effects of pH and extraction methods

Stinky beans (Parkia speciosa) were hydrodistilled and solvent-extracted and the oil obtained was analyzed by GC-MS/FID. Nine cyclic and one acyclic organosulfides were identified comprising 36% of total volatiles. Solvent extracts contained significantly (p < 0.05) higher total organosulfides (680 ppm) as compared to distilled oil (444 ppm). The concentrations of organosulfides are highly dependent on the pH values of the matrix, with control sample (pH 5.40) giving the highest total organosulfides (424 ppm) followed by that of pH 7.0 (234 ppm), pH 9.0 (195 ppm), and pH 3.0 (152 ppm). The H2S-releasing capacity, expressed as diallyl trisulfide equivalents (DATS-E in mmol DATS/g), corresponded well with the differences in organosulfide concentrations as affected by pH with control having the highest value (24.35) followed pH 7.0 (7.27), pH 9.0 (3.27), and pH 3.0 (1.80). We conclude that stinky bean oil is a potent H2S-releasing agent that could have health-beneficial properties.

Effect of processing conditions on the organosulfides of shallot (Allium cepa L. Aggregatum group)

There is a growing account of the health benefits of H2S as an endogenous cell-signaling molecule. H2S from organic polysulfides, in particular, is increasingly gaining attention for their beneficial effects to cardiovascular health. Here, we studied shallot as a potential dietary source of organic polysulfides and examined the effects of processing conditions on its polysulfide profiles. Boiling, autoclaving, and freeze-drying were tested on whole and crushed shallot bulbs, analyzing their effect on the yield of organosulfides. Seventeen organosulfides, including disulfides, trisulfides, and cyclic polysulfides, were identified. Significant differences in the quantitative and qualitative profiles of organosulfides in the hydrodistilled and solvent extracted oils were observed. Freeze-drying retained the majority of the organosulfides, but the whole-autoclaved and whole-boiled shallots lost more than 95% of their organic polysulfides. Crushed-boiled and crushed-autoclaved shallot lost 76-80% of their organosulfides, likely due to the thermal sensitivity of these compounds. The organosulfide profiles are sensitive to the pH values of the processing media. In general, disulfides increased at basic pH (pH 9.0) while trisulfides and cyclic organosulfides are much higher at the acidic to neutral pH values (pH 3.0-5.0). Our results provide important information on the effects of processing conditions that are relevant for optimizing extraction of organosulfides from shallot for further studies evaluating their H2S-releasing activity.