Effect of Oral Administration of S-allyl Cysteine (the Active Ingredient in the Aged Garlic Extract) on the Symptoms of Multiple Sclerosis in the Experimental Model

Autoimmune inflammation of the central nervous system followed by myelin destruction, oxidative stress, and reduced neuroprotective factors play key roles in the pathogenesis of multiple sclerosis (MS). S-allyl cysteine (SAC), an active ingredient in the aged garlic extract, has known anti-inflammatory and neuroprotective effects. Therefore, this study aimed to investigate the anti-inflammatory and neuroprotective effects of S-allyl cysteine and related mechanisms in experimental autoimmune encephalomyelitis (EAE, a validated animal model of MS).

C57BL/6 mice were divided into the following three groups, with each group comprising of ten animals: Group 1: Control, Group 2: EAE induction, and Group 3: EAE induction and daily administration of SAC (EAE+SAC). The EAE induction was performed using the Hooke kit. It should be noted that daily gavage of SAC was carried out and clinical score (severity of tail and limbs paralysis) was assessed daily. The inflammation of the lumbar spinal cord was measured through hematoxylin and eosin staining. Moreover, tumor necrosis factor α (TNF-α) level in spinal cord and serum; Interleukin17(IL-17, Inflammatory factors) level in spinal cord; Activity-dependent neuroprotector homeobox (ADNP), and Microtubule-associated Proteins 1A/1B Light Chain 3A (MAP1LC3A, neuroprotective factors) were measured using ELISA. The data were analyzed using a one-way analysis of variance.

The daily administration of SAC significantly reduced the score of clinical paralysis on days 13 to 18 following EAE induction (from P>0.05 to P<0.01). It also significantly reduced spinal cord inflammation (P<0.01), elevated levels of TNFα in serum and spinal cord, and IL-17 in the spinal cord (P<0.05). On the other hand, daily administration of SAC elevated the reduced spinal cord levels of ADNP and MAP1LC3A (P<0.05).

Daily oral administration of SAC improved MS symptoms through the reduction of spinal inflammation and inflammatory factors, and elevation of neuroprotective factors. In addition, SAC can be utilized in the prevention and treatment of MS due to its herbal origin.