Antibacterial action of an aqueous grape seed polyphenolic extract

The potential of a polyphenolic grape seed extract for use as a natural antibacterial agent was evaluated. Pure catechin (CS) and a previously LC-MS characterized grape seed phenolic extract (PE) were evaluated as antibacterial agents against Escherichia coli and Brevibacterium linens on solid and in liquid culture media. After 48 h incubation on solid medium, PE had a bactericidal effect on the gram positive B. linens and a reduction of the microbial growth for E. coli. The antibacterial agents tested were effective against E. coli for 13 h, after 7 h incubation, but ineffective against B.linens in liquid medium. CS and PE both had an antibacterial effect depending on incubation time.Key words: Catechin, polyphenolic extract, antibacterial activity, Brevibacterium linens, Escherichia coli B41

Resveratrol: biological activities and potential use in health and disease

Resveratrol (RV) is a polyphenol non-flavonoid compound present in strongly pigmented vegetables and fresh fruits as well as dried nuts such as peanuts. High concentrations of this natural compound were found, in the modern occidental world, in the peel of the berries of the red grape Vitis vinifera, but usage of this natural drug in popular medicine has been documented much earlier. Resveratrol exhibits diverse biological activities such as antitumor, antioxidant, antiviral, and phytoestrogenic. In particular, as the work reported from our laboratories, the compound shows an inhibitory effect on murine polyomavirus DNA replication, while at higher concentrations, RV shows a significant cytotoxic effect. This complex dose-dependent behavior is not intrinsic to the drug. Other natural substances behave in a similar way, curcumin and a semi-purified fraction of the whole neem oil being two different examples. Most likely, the administration of RV to cultured cells alters the permeability and fluidity of the cell membrane. Also, data presented in literature ascribe to RV an antiproliferative action, thus rendering this drug a good candidate for the control of neoplastic growth. The potential usage of RV both in human and veterinary medicine is also examined in this review