Antibacterial activity grapefruit

Though it has proved impossible to discover the process used to make commercial GSE, there is significant evidence that the grapefruit plant and all the citrus family possess potent antibacterial activity. A cursory reading of the Literature shows reliable activity against Staphylococcus, Salmonella,... 

P. S. Negi, G. K. Jayaprakasha (2001) Antibacterial activity of grapefruit (Citrus paradisi) peel etitiacts. Euk Food Res. Technol 213, 484-487. 

The mold from which Fleming discovered penicillin was Penicillium notatum, a strain that gives a relatively low yield of penicillin. Commercial production of the antibiotic uses P. chrysogenum, a strain cultured from a mold found growing on a grapefruit in a market in Peoria, Illinois. The penicillins owe their antibacterial activity to a common mechanism that inhibits the biosynthesis of a vital part of bacterial cell walls. 

Grapefruit oil is reported to have antibacterial activities. Its chromenone constituent has been shown to enhance antibiotic effect against MSSA and MRSA by acting as an inhibitor of the bacterial efflux pump mechanism. ... 

---