Hydrogen sulphide (H2S) releasing capacity of essential oils isolated from organosulphur rich fruits and vegetables

Hydrogen sulphide (H2S) is a gaseous signalling molecule with multiple biological functions in the human body. Previous research demonstrates that diallyl trisulphide (DATS) and diallyl disulphide (the two major compounds of garlic oil) can be metabolized to generate H2S in biological conditions and modulate cell signalling. In this paper, a fluorescent method for quantification of H2S releasing capacity in cell lines was developed. MCF-7 cells in 96 well plate were incubated with a H2S probe BCu for 3 h, then treated with H2S donors for 2 h, which would be metabolized by the cells and produce H2S. The resulting H2S was captured by the probe and turn on its fluorescence, which was measured with a microplate reader. Linear dose response could be established between organosulphur concentration and fluorescence intensity, and the H2S releasing capacity of a sample was determined by comparing the slope of the regression curve with that of a DATS standard obtained in parallel. With this method, the H2S releasing capacity of ten organosulphur rich fruits and vegetables (garlic, red onion, yellow onion, scallion, shallot, leek, spring onion, Chinese chives, durian, and stinky beans) were evaluated and ranked. Stinky beans (a vegetable from Southeast Asia) topped the ranking with very high H2S releasing capacity, followed by garlic and yellow onion. Our work provides new thinking on the health benefits of organosulphur-rich foods.