R- Is Superior to S-Form of α-Lipoic Acid in Anti-Inflammatory and Antioxidant Effects in Laying Hens

Abstract

The development of single enantiomers with high efficiency and low toxic activity has become a hot spot for the development and application of drugs and active additives. The aim of the present study was to investigate the effectiveness of the application of α-lipoic acid with a different optical rotation to alleviate the inflammation response and oxidative stress induced by oxidized fish oil in laying hens. Sixty-four 124-week-old Peking Red laying hens were randomly allocated to four groups with eight replicates of two birds each. The normal group was fed basal diets supplemented with 1% fresh fish oil (FO), and the oxidative stress model group was constructed with diets supplemented with 1% oxidized fish oil (OFO). The two treatment groups were the S-form of the α-lipoic acid model with 1% oxidized fish oil (OFO + S-LA) and the R-form of the α-lipoic acid model with 1% oxidized fish oil (OFO + R-LA) added at 100 mg/kg, respectively. Herein, these results were evaluated by the breeding performance, immunoglobulin, immune response, estrogen secretion, antioxidant factors of the serum and oviduct, and pathological observation of the uterus part of the oviduct. From the results, diets supplemented with oxidized fish oil can be relatively successful in constructing a model of inflammation and oxidative stress. The OFO group significantly increased the levels of the serum inflammatory factor (TNF-α, IL-1β, IL-6, and IFN-γ) and the oxidative factor MDA and decreased the activity of the antioxidant enzyme (T-AOC, T-SOD, GSH-Px, GSH, and CAT) in the oviduct. The addition of both S-LA and R-LA significantly reduced the levels of serum inflammatory factors (TNF-α, IL-1β, IL-6, and IFN-γ), increased the activity of antioxidant indexes (T-AOC, T-SOD, GSH-Px, GSH, and CAT), and decreased the MDA contents in the serum and oviduct. Meanwhile, the supplementation of S-LA and R-LA also mitigated the negative effects of the OFO on the immunoglobulins (IgA and IgM) and serum hormone levels (P and E2). In addition, it was worth noting that the R-LA was significantly more effective than the S-LA in some inflammatory (IL-1β) and antioxidant indices (T-SOD, GSH, and CAT). Above all, both S-LA and R-LA can alleviate the inflammation and oxidative damage caused by oxidative stress in aged laying hens, and R-LA is more effective than S-LA. Thus, these findings will provide basic data for the potential development of α-lipoic acid as a chiral dietary additive for laying hens.

Nanotechnological Approaches to Enhance the Potential of α-Lipoic Acid for Application in the Clinic

“…R(+)-α-lipoic acid is generally recognized to exhibit superior activity compared to S(-)-α-lipoic acid [ 2 , 3 , 4 , 5 , 6 ], even as α-lipoic acid is usually marketed as a racemic mixture containing both enantiomers. To date, the extent to which each enantiomer contributes to α-lipoic acid pharmacological and toxicological effects is not fully understood.…”

“…To date, the extent to which each enantiomer contributes to α-lipoic acid pharmacological and toxicological effects is not fully understood. While it was proposed that S(-)-α-lipoic acid does not exhibit significant biological side effects [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ], some studies indicated that it could potentially hinder the activity of the R(-)-enantiomer [ 8 , 9 , 10 ].…”

“…The chiral centre at position C6 results in two enantiomers, R(+)-α-lipoic acid, the naturally available form, and S(-)-α-lipoic acid, which can be synthetically obtained [1]. R(+)-α-lipoic acid is generally recognized to exhibit superior activity compared to S(-)α-lipoic acid [2][3][4][5][6], even as α-lipoic acid is usually marketed as a racemic mixture containing both enantiomers. To date, the extent to which each enantiomer contributes to α-lipoic acid pharmacological and toxicological effects is not fully understood.…”