Table 2.

Examples of herbal medicine and their extracts that modulate gut microbiota and their influences on AD

	Examples	Connections with Microbiota	Influences on AD	References
Herbal Medicine and their extracts	TTK	Erysipelotrichales, Clostridiales, Desulfovibrionales, Enterobacteriales ↓; Bacteroidales and Lactobacillales ↑	Amyloid deposit ↓, the memory function ↑	[41]
	Rg1	Population of Lactobacillus salivarius ↑; abundance of Bacteroidetes ↓	Production of Aβ ↓, cognitive impairment ↓	[42]
	DHF	Detrimental bacteria ↓; gut microbial diversity in female ↑, but not male, mice	Synaptic loss ↓, restoring synaptic plasticity ↑, Aβ deposition ↓	[26, 43]
	OMO	Proinflammatory microbiota↓; anti-inflammatory microbiota ↑	Brain tissue swelling ↓, neuronal loss ↓, levels of AD intracellular markers ↓	[44]

↑: Higher, ↓: Lower, TTK: Tetragonia tetragonioides Kuntze, Rg1: Ginsenoside Rg1, DHF: flavonoid 7,8-dihydroxyflavone, OMO: Oligosaccharides extracted from M. officinalis