Interaction of aspirin and vitamin C with bovine serum albumin

• Published in: Journal of photochemistry and photobiology. B, Biology Vol. 105; no. 3; pp. 198 - 202
• Main Authors: Nafisi, Shohreh, Bagheri Sadeghi, Golshan, PanahYab, Ataollah
• Format: Journal Article
• Language: English
• Published: Switzerland Elsevier B.V 02-12-2011
• Subjects: Animals; Anti-Inflammatory Agents, Non-Steroidal - metabolism; Anti-Inflammatory Agents, Non-Steroidal - pharmacology; Antioxidants - chemistry; Antioxidants - metabolism; Antioxidants - pharmacology; Ascorbic acid; Ascorbic Acid - chemistry; Ascorbic Acid - metabolism; Ascorbic Acid - pharmacology; Aspirin; Aspirin - chemistry; Aspirin - metabolism; Aspirin - pharmacology; BSA; Cattle; Dose-Response Relationship, Drug; FT-IR; Protein Binding; Protein Conformation - drug effects; Protein Stability - drug effects; Serum Albumin, Bovine - chemistry; Serum Albumin, Bovine - metabolism; Spectroscopy, Fourier Transform Infrared; UV–Vis spectroscopy; BSA; FT-IR; Aspirin; Ascorbic acid; UV–Vis spectroscopy
• ISSN: 1011-1344; 1873-2682
• DOI: 10.1016/j.jphotobiol.2011.09.002

► The binding constant of vitamin C-BSA was measured higher than aspirin-BSA. ► At low drugs concentration, no major protein conformational changes occur. ► At high drugs contents, significant decrease of secondary structures was observed. ► A partial protein destabilization was occurred at high drug concentrations. ► BSA can be considered as a good carrier for vitamin C and aspirin in vitro.
Vitamin C (L-ascorbic acid) has a major biological role as a natural antioxidant. Aspirin belongs to the nonsteroidal anti-inflammatory drugs and functions as an antioxidant via its ability to scavenge-OH radicals. Bovine serum albumin (BSA) is the major soluble protein constituent of the circulatory system and has many physiological functions including transport of a variety of compounds. In this report, the competitive binding of vitamin C and aspirin to bovine serum albumin has been studied using constant protein concentration and various drug concentrations at pH 7.2. FTIR and UV–Vis spectroscopic methods were used to analyze vitamin C and aspirin binding modes, the binding constants and the effects of drug complexation on BSA stability and conformation. Spectroscopic evidence showed that vitamin C and aspirin bind BSA via hydrophilic interactions (polypeptide and amine polar groups) with overall binding constants of
K
vitamin C-BSA
=
1.57
×
10
4
M
−1 and
K
aspirin-BSA
=
1.15
×
10
4
M
−1; assuming that there is one drug molecule per protein. The BSA secondary structure was altered with major decrease of α-helix from 64% (free protein) to 57% (BSA-vitamin C) and 54% (BSA-aspirin) and β-sheet from 15% (free protein) to 6–7% upon drug complexation, inducing a partial protein destabilization.