Enzymatic acylation of lutein with a series of saturated fatty acid vinyl esters and the thermal stability and anti-lipid oxidation properties of the acylated derivatives

Lutein was enzymatically acylated with saturated fatty acid vinyl esters of different lengths of carbon chain (C₆ -C₁₄ ) under the action of Candida antarctica lipase B (Novozyme 435). The acylation reaction was optimized by considering substrate molar ratio, reaction solvent, type of enzyme, and reaction time. The highest yield (88%) was obtained using the Novozyme 435 to catalyze the acylation reaction of lutein and vinyl decanoate (lutein/vinyl decanoate molar ratio of 1/10) for 16 h in methyl tert-butyl ether. Ten lutein esters were synthesized, isolated, and purified, which were characterized by Fourier-transform infrared spectroscopy, high-resolution mass spectrometry, and nuclear magnetic resonance spectroscopy. We found that the acylation of lutein improved its antioxidant capacity in lipid system and thermal stability. Our study extended the potential application of lutein in lipophilic food, cosmetic, and pharmaceutical industries. Practical Application: Enzyme acylation of lutein improved its antioxidant capacity in lipid system and thermal stability, extended its potential application in food, cosmetic, and pharmaceutical industries. In addition, our study also provided a new perspective and cognition for the further development and utilization of lutein.

Enzymatic acylation of rutin with benzoic acid ester and lipophilic, antiradical, and antiproliferative properties of the acylated derivatives

Rutin (3',4',5,7-tetrahydroxy-flavone-3-rutinoside) was enzymatically acylated with benzoic acid and its esters (methyl benzoate and vinyl benzoate) using Thermomyces lanuginosus lipase (Lipozyme TLIM). The acylation reaction was optimized by varying the reaction medium, reaction temperature, acyl donor, substrate molar ratio, and reaction time. The highest conversion yield (76%) was obtained in tert-amyl alcohol (60 °C, 72 hr) using vinyl benzoate (molar ratio of 1:10) as acyl donor. The acylation occurred at the 2'''-OH and 4'''-OH of the rhamnose unit and the 2''-OH position of the glucose moieties. Three novel rutin acylated derivatives (compounds 1-3) were purified and characterized by HR-MS and 1D and 2D NMR spectroscopy. We found that acylation significantly improved lipophilicity, capacity to inhibit lipid peroxidation, anticancer capacity and substantially maintained the antioxidant activity of rutin. This research provides important insights in the acylation of flavonoids with different glycosyl moieties. PRACTICAL APPLICATION: In this study, three novel rutin derivatives were successfully synthesized and the highest conversion yield (76%) was obtained by reacting the rutin and vinyl benzoate at molar ratio of 1:10 in tert-amyl alcohol for 72 hr at 60 °C. Introducing a benzoic acid substituent into rutin molecule significantly improved their lipophilicity and inhibition of lipid peroxidation in lipophilic system. Furthermore, this study demonstrated that acylation significantly improved anticancer capacity and substantially maintained the antioxidant activity.

Characterization of phenolic constituents inhibiting the formation of sulfur-containing volatiles produced during garlic processing

Garlic (Allium sativum L.), which is a widely distributed plant, is globally used as both spice and food. This study identified five novel phenolic compounds, namely, 8-(3-methyl-(E)-1-butenyl)diosmetin, 8-(3-methyl-(E)-1-butenyl)chrysin, 6-(3-methyl-(E)-1-butenyl)chrysin, and Alliumones A and B, along with nine known compounds 6-14 from the ethanol extract of garlic. The structures of these five novel phenolic compounds were established via extensive 1D- and 2D-nuclear magnetic resonance spectroscopy experiments. The effects of the phenolic compounds isolated from garlic on the enzymatical or nonenzymatical formation of sulfur-containing compounds produced during garlic processing were examined. Compound 12 significantly reduced the thermal decomposition of alliin, whereas compound 4 exhibited the highest percentage of alliinase inhibition activity (36.6%).

trans-3,3′,4,5′-Tetramethoxystilbene

The title compound, C₁₈H₂₀O₄, was synthesized by a Wittig–Horner reaction of diethyl 3,4-dimeth­oxy­benzyl­phosphate and 3,5-dimeth­oxy­benzaldehyde. In the crystal, the dihedral angle between the two aromatic rings is 2.47 (12)°. All the meth­oxy groups are almost coplanar with the aromatic ring to which they are attached [C—C—O—C torsion angles = −2.8 (3), −5.2 (4), −176.3 (2) and −178.0 (2)°].

1,2-Bis(4-nitro-benz-yl)diselane

The title compound, C₁₄H₁₂N₂O₄Se₂, is not chiral, but the mol­ecules assume a chiral conformation in the solid state and crystallize as an aggregate. The central C—Se—Se—C torsion angle is 90.4 (2)°, while the two Se—Se—C—C fragments assume gauche conformations with values of −59.4 (5) and 67.5 (4)°. The dihedral angle between the two benzene rings is 80.74 (14)°.

(±)-4a-(4-Nitro-benz-yl)-2,3,4,4a-tetra-hydro-1H-carbazole

The title mol-ecule, C(19)H(18)N(2)O(2), is built up from three fused rings, viz. phenyl, pyrrole and cyclo-hexane, linked to a nitro-benzyl group. The C atom bearing the nitro-benzyl group is chiral and the compound is a racemate (R/S). The dihedral angle between the nitro-benzyl and indole rings is 57.49 (5)°. The cyclo-hexane ring adopts a slightly distorted chair conformation.