Breyniaionoside D from Huai yam attenuates Alzheimer’s disease-like pathological changes associated with calcium dysregulation and neuroinflammatory signaling

Alzheimer’s disease is accompanied by disrupted excitatory signaling, calcium dyshomeostasis and sustained neuroinflammatory activation, all of which may contribute to progressive neuronal injury. This study examined whether Breyniaionoside D, a purified natural compound from Huai yam, modifies Alzheimer’s disease-related abnormalities and explored the possible association of these effects with N-methyl-D-aspartate receptor-related signaling. Breyniaionoside D was evaluated in 5 × FAD mice, N2a/APP695 cells and an aluminum chloride-induced adult zebrafish model. Behavioral testing, histological analysis, biochemical assays, flow cytometry, in vivo calcium recording, surface plasmon resonance, microbiota profiling and brain metabolomics were used to assess neuronal injury, inflammatory responses and calcium-related signaling. In 5 × FAD mice, Breyniaionoside D was associated with improved performance in cognitive and exploratory behavioral tests, reduced amyloid burden, and attenuation of neuronal injury, oxidative stress, glial activation and pro-inflammatory signaling. It was also associated with changes in abnormal calcium signals and NMDAR2B/PKG/CaMK-2-related signaling markers. Microbiota profiling and brain metabolomics revealed parallel, treatment-associated changes in gut microbial composition and brain metabolites enriched in alanine, aspartate and glutamate metabolism. Surface plasmon resonance indicated detectable in vitro binding between Breyniaionoside D and an NMDAR2B fragment. In N2a/APP695 cells and zebrafish, pharmacological interference with NMDAR signaling modified several effects of Breyniaionoside D, consistent with the possible involvement of NMDAR-related pathways. These findings suggest that Huai yam-derived Breyniaionoside D attenuates Alzheimer’s disease-like pathological changes in complementary experimental models with distinct pathological contexts and that these effects may be associated with calcium dysregulation, NMDAR-related signaling and neuroinflammatory responses.