title: Binding effect of proline-rich-proteins (PRPs) on in vitro antimicrobial activity of the flavonoids.
abstract: The interaction of the cyanidin, pelargonidin, catechin, myrecetin and kaempferol with casein and gelatin, as proline rich proteins (PRPs), was studied. The binding constants calculated for both flavonoid-casein and flavonoid-gelatin were fairly large (10 (5) -10 (7) M (-1) ) indicating strong interaction. Due to higher proline content in gelatin, the binding constants of flavonoid-gelatin (2.5 × 10 (5) -6.2 × 10 (7) M (-1) ) were found to be higher than flavonoid-casein (1.2 × 10 (5) -5.0 × 10 (7) M (-1) ). All the flavonoids showed significant antibacterial activity against the tested strains. Significant loss in activity was observed due to the complexation with PRPs confirming that binding effectively reduced the concentration of the free flavonoids to be available for antibacterial activity. The decline in activity was corresponding to the values of the binding constants. Though the activities of free catechin and myrecetin were higher compared to pelargonidin, cyanidin and kaempferol yet the decline in activity of catechin and myrecetin due to complexation with casein and gelatin was more pronounced.
authors.affiliation: Department of Food Science & Technology, University of Karachi, Karachi, Pakistan.
authors.forename: Jawaad Ahmed
authors.initials: JA
authors.lastname: Ansari
authors.affiliation: Department of Food Science & Technology, University of Karachi, Karachi, Pakistan.
authors.forename: Shahina
authors.initials: S
authors.lastname: Naz
authors.affiliation: Food Technology Section, Food and Marine Resources Research Centre, Laboratories Complex, Karachi, Pakistan.
authors.forename: Omer Mukhtar
authors.initials: OM
authors.lastname: Tarar
authors.affiliation: Department of Food Science & Technology, University of Karachi, Karachi, Pakistan.
authors.forename: Rahmanullah
authors.initials: R
authors.lastname: Siddiqi
authors.affiliation: Food Technology Section, Food and Marine Resources Research Centre, Laboratories Complex, Karachi, Pakistan.
authors.forename: Muhammad Samee
authors.initials: MS
authors.lastname: Haider
authors.affiliation: Food Technology Section, Food and Marine Resources Research Centre, Laboratories Complex, Karachi, Pakistan.
authors.forename: Khalid
authors.initials: K
authors.lastname: Jamil
mesh_terms: D000890:Anti-Infective Agents / Q000378:metabolism* / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D002364:Caseins / Q000378:metabolism*; D005419:Flavonoids / Q000378:metabolism* / Q000494:pharmacology; D005780:Gelatin / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D011485:Protein Binding
chemical_list: D000890:Anti-Infective Agents; D002364:Caseins; D005419:Flavonoids; D005780:Gelatin
keywords: binding constants; casein; catechin; cyanidin; flavonoids; gelatin; kaempferol; myrecetin; pelargonidin; proline rich proteins