Shilajit, a Natural Phytocomplex Acts as a Neuroprotective Agent Against Amyloid Beta-induced Cytotoxicity and Inflammation

Abstract

Background: Shilajit is a natural phytocomplex known for centuries in Ayurveda traditional medicine for its antioxidant, immunomodulatory, and neuroprotective properties. However, there is little published scientific evidence to support these acclaimed properties.Methods: The safety, regarding the heavy metal content, component analysis, the neuroprotective effects and amyloid beta (Aβ)-induced cytotoxicity and inflammation of 3 samples of Shilajit derived from different geographical origins were assessed. Neuroprotective effects of Shilajit were examined using neuroblastoma cell lines (SH-SY5Y and IMR-32) and cell viability assays. The inhibitory effect on the proinflammatory cytokine derived from macrophage cells was assessed using bone marrow-derived macrophage cells in vitro and in a murine model of Aβ-induced inflammation (ex vivo analysis).Results: The results showed that a daily dose of each Shilajit sample were within the permissible heavy metal limit established by the United States Food and Drug Administration. The 3 Shilajit samples alleviated Aβ-induced toxicity in neuronal cells. One sample derived from the Altai Mountains suppressed Aβ-induced processing of pro-interleukin (pro-IL)-1β into mature, biologically active IL-1β in macrophages. This Shilajit sample inhibited Aβ-induced production of the proinflammatory cytokine IL-1β in the brain (ex vivo analysis). In component analysis, this sample was enriched in salicyluric acid.Conclusion: Shared and distinct properties were observed among the 3 Shilajit samples concerning their neuroprotective effects, and regarding safety, the daily dose of each Shilajit had a safe level of heavy metal content. Salicyluric acid in Shilajit may be important in mitigating Aβ-induced inflammatory cytokine but more research is necessary.