Herbal Neurotherapeutics for Cognitive Disorders: Integrative Mechanisms Linking Neurotransmitter Systems, Neurodegeneration, and the Gut-Brain Axis

Cognitive disorders such as Alzheimer's disease, Parkinson's disease, schizophrenia, depression, and vascular dementia share a common thread: disruption of the brain's chemical messaging systems. This systematic review examined how herbal medicines might address those disruptions through multiple biological pathways simultaneously — something conventional drugs rarely achieve. The researchers surveyed preclinical and clinical evidence for several medicinal plants, including Moringa oleifera, Bacopa monnieri, Withania somnifera, Ginkgo biloba, Glycyrrhiza glabra, and ginseng, assessing how their bioactive compounds interact with neurotransmitter systems involving acetylcholine, dopamine, serotonin, glutamate, and GABA. Beyond neurotransmitters, the review mapped how these herbs may counter oxidative stress, neuroinflammation, mitochondrial dysfunction, and disruption of the gut-brain axis — a communication highway between the digestive system and the brain that is increasingly implicated in cognitive decline. The review also explored advanced delivery technologies such as nanoparticles and phytosomes, which may help herbal compounds cross the blood-brain barrier more effectively and reach their targets at therapeutic concentrations. The overall conclusion is cautiously optimistic: herbal neurotherapeutics show genuine mechanistic promise, but the clinical evidence base remains fragmented. Studies are too small, too short, and too inconsistently designed to support firm recommendations. Moringa oleifera appears as one of several herbs with experimental support for neuroprotection, though the review does not isolate it as superior to others. The authors call for large-scale, standardised clinical trials before herbal approaches can be formally integrated into neurological care.