Table 3.

Singlet oxygen steady state concentrations [${}^1{\mathrm{O}}_2$] and second order rate constant ($k_{{}^1{\mathrm{O}}_2,\mathrm{X}}^{II}$ ) between singlet oxygen and silibinin (1) or dimers (6–8) in THF and H₂O solutions.

Compound	THF		H2O
	[${}^{\mathit{1}}{\mathbf{O}}_{\mathbf{2}}$]SS (M)	${\mathit{k}}_{{}^{\mathbf{1}}{\mathbf{O}}_{\mathbf{2}},\mathbf{X}}^{\mathit{I}\mathit{I}}$ (M−1s−1)	[${}^{\mathit{1}}{\mathbf{O}}_{\mathbf{2}}$]SS (M)	${\mathit{k}}_{{}^{\mathbf{1}}{\mathbf{O}}_{\mathbf{2}},\mathbf{X}}^{\mathit{I}\mathit{I}}$ (M−1·s−1)
1	3.79 × 10−13	6.1 ± 0.4 × 107	-	-
6	-	-	4.07 × 10−13	6.8 ± 1.2 × 107
7	-	-	4.07 × 10−13	5.4 ± 0.3 × 107
8	-	-	4.07 × 10−13	4.0 ± 0.2 × 107