Unraveling the Anti-Alzheimer's mechanisms of optimal constituent from Arisaema heterophyllum Blume through multi-model and phytochemical analysis.

BACKGROUND: Alzheimer's disease (AD) is one of the most significant health threats globally, with limited therapeutic options currently available. Arisaema heterophyllum Blume (AhBl), a traditional Chinese herb, has been used as a medicine for centuries, yet its neuroprotective effects toward AD have not been systematically studied. PURPOSE: This study aimed to evaluate the anti-AD effects and pharmacological mechanisms of AhBl ethanol extracts (EE), as well as to identify the optimal active constituent. METHODS AND RESULTS: AhBl EE significantly alleviated AD-like symptoms. The 2:1 MeOH/DCM elution fraction showed the most potent activity, improving dyskinesia, reducing cerebral amyloid-β (Aβ) deposition and neuronal apoptosis, inhibiting acetylcholinesterase activity, and mitigating blood-brain barrier (BBB) leakage. Through integrated phytochemical characterization, bioinformatic prediction, and pharmacological evaluation, the linoleic acid was identified as the optimal active constituent. In addition to alleviating AD-like symptoms in zebrafish larvae, the linoleic acid exhibited similar effects in the AD model in adult zebrafish, improving preference, learning and memory, and exploratory abilities. Furthermore, it significantly restored abnormal gene expression in the regulation of learning and memory, as well as in BBB and cholinergic system functions. In cellular AD models, the linoleic acid enhanced Aβ clearance and promoted a shift from pro-inflammatory M1 to anti-inflammatory M2 microglial polarization, confirming its anti-AD action. These findings suggest that the mechanism of the linoleic acid action involves reversing BBB disruption, thereby preventing the effect of neurotoxins such as Aβ from damaging cholinergic neurons and subsequently slowing AD progression. CONCLUSIONS: Our findings demonstrated for the first time that the linoleic acid is an optimal anti-AD active constituent of AhBl. Its basic mechanisms involve reversing BBB disruption and protecting cholinergic neurons from damage, thereby supporting its potential as a promising candidate for AD therapy.