Myrosinase hydrolysates of Brassica oleraceae L. var. italica Plenck
Phytochemicals, especially the secondary metabolites synthesized by plants, play key roles in human nutrition, health, wellness and disease prevention. Preliminary studies using LC-ESI, provides a simple, rapid technique for the analysis, that is suitable for routine screening of plant materials. Two glucosinolates were identified in the aqueous extract of Brassica oleraceae L. var. italica Plenck, glucoiberin and 3-hydroxy, 4(α-L-rhamnopyranosyloxy) benzyl glucosinolate, they were identified by liquid chromatography- negative ion electrospray mass spectrometry (LC- ESI) . Two compounds were isolated after enzymatic hydrolysis of the aqueous extract by myrosinase, one of them was identified as 4-vinyl-3-pyrazolidinone. The second compound (sulphoraphane) 1-isothiocyanate-4-methyl-sulphinyl butane, converted to the most stable form of thiourea, (sulphoraphane thiourea) .
The crude extract (80% alcohol extract) of broccoli florets was examined for cytotoxic activity against different cell lines , it showed good inhibition to colon tumor (IC50 3.88µg). But when the same test was repeated on each successive extract no significant cytotoxic activity produced with any of them. When myrosinase hydrolysate was tested for cytotoxic activity on colon tumor cell line, it showed very high activity 95% lethality up to 0.78µg/mL..
Acknowledgement: Hamed A. for performing LC-ESI. Institute of natural medicine, Toyama university, Toyama, Japan.
References: 1. William CK et al. (1998)J Agric Food Chem 46: 1018–1012.
2. Hashem FA, Wahba HE (2000) Phytother Res 14: 284–287.
3. Zhang Y, Talalay P (1994) Cancer Res 54 (Suppl.): 1976s-1981s.