Contribution of the Glucosinolate Fraction to the Overall Antioxidant Potential, Cytoprotection against Oxidative Insult and Antimicrobial Activity of Mill. Leaves Extract.

BACKGROUND

Mill. (Brassicaceae) is commonly utilized as an ingredient in salads and also as a folk remedy to treat various diseases.

OBJECTIVE

The objective of this study was to establish the contribution of the glucosinolate (GLS) fraction to the overall antioxidant, cytoprotection against oxidative insult and antimicrobial properties of the hydro-alcoholic extract of leaves from Sicily (Italy), characterized phytochemically.

MATERIALS AND METHODS

The antioxidant activity was evaluated by different systems. The cytoprotective effect against hydrogen peroxide (HO)-induced oxidative stress was tested in human peripheral blood mononuclear cells (PBMCs). The antimicrobial potential against bacteria and fungi was assayed by standard methods.

RESULTS

extract exhibited both radical scavenging (50% inhibitory concentration [IC] 1.04 ± 0.04 mg/mL) and ferrous ions-chelating activity (IC 0.327 ± 0.0032 mg/mL) and mild reducing power; the GLS fraction showed chelating ability only (IC 0.225 ± 0.009 mg/mL). In the experimental model of HO-induced oxidative stress in human PBMCs, a significant cytoprotective effect and a suppression of reactive oxygen species production by both extract and GLS fraction were observed ( < 0.001). extract displayed moderate antimicrobial activity against Gram-positive bacteria, and was the most sensitive strain (minimum inhibitory concentration 0.125 mg/mL), whereas the GLS fraction was not active.

CONCLUSION

GLSs are not involved in the primary antioxidant activity of leaf extract but they are, almost in part, responsible for its ferrous ion-chelating properties. Iron-chelating compounds in extract may protect cells under conditions of oxidative stress, and GLSs might play a chief role in this effect.

SUMMARY

Mill. leaf extract exhibited antioxidant activity in different systems, whereas the glucosinolate (GLS) fraction showed Fe-chelating ability onlyA significant cytoprotective effect and a suppression of intracellular reactive oxygen species production by both extract and GLS fraction were observed in human peripheral blood mononuclear cells extract displayed moderate antimicrobial activity against Gram-positive bacteria, whereas the GLS fraction was not active. GLS: Glucosinolate; HO: Hydrogen peroxide; PBMCs: Peripheral blood mononuclear cells; IC: 50% inhibitory concentration; MIC: Minimum inhibitory concentration.