Showing papers on "Galangin published in 1987"

Antibacterial Activity of Flavonoids against Staphylococcus epidermidis, a Skin Bacterium

Abstract: An investigation was carried out on Okinawan plants to find antibacterial compounds against a human skin bacterium, Staphylococcus epidermidis, which causes acne vulgaris. A medicinal plant, Elaeagnus glabra, showed significant activity, and (—)-epigallocatechin (27) was isolated from the plant as an antibacterial constituent against the bacterium. Twenty-six flavonoids related to 27 were tested for the activity, galangin (7) being the most active species. Although a structure-activity study was attempted, no clear structural factor was deduced.

Enhancement of the mutagenicity of 2-acetylaminofluorene by flavonoids and the structural requirements.

Abstract: The enhancing effects of 12 kinds of flavonoids on the mutagenicity of 2-acetylaminofluorene (AAF) in Salmonella typhimurium TA98 were investigated. In the mixed applications of AAF (22.4 nmoles/plate) with flavonoids (31.4-45.0 nmoles/plate) in the presence of a mammalian metabolic activation system (S9 mix), morin, galangin, flavonol, kaempferol, quercetin and myricetin enhanced the mutagenicity of AAF by 3.3-10.2-fold. The potency of the mutagenicity enhancing effects increased in the described order. For the mutagenicity-enhancing effects of the flavonoids on AAF, the flavonol structure, including the free 3-hydroxyl group and the 2,3-double bond, were essential. In the quercetin analogues, the 5-hydroxyl group was also essential. Further, the numbers of the hydroxyl groups substituted at the 3', 4' and 5'-positions in the B-ring contributed to an increase of the enhancing effect, whereas the substitution of a hydroxyl group at the 2'-position depressed the potency of the effect.