Table 3.

Different categories of alkaloids in extraction methods and neurodegenerative diseases

Category	Example	Extraction method	Pharmacological mechanism in AD	References
Piperidine alkaloids	Piperine	Methanol extraction	Reduce GSH, MDA	[74]
Isoquinoline alkaloid	BBR	Water decoction	Inhibits AChE, BChE activity and β-secretase	[75]
Indole alkaloids	Evo	Hot water reflux extraction	Inhibits AChE	[76]
Terpenoids alkaloids	Voacangine	90% ethanol reflux extraction	Inhibits AChE	[77]
Steroidal alkaloids	Conessine	90% ethanol extraction	Inhibits AChE and the activation of NF-κB	[78]
	Corynoxine	70% ethanol reflux extraction	Reduce Ca2+ overload and tau protein hyperphosphorylation	[79]
Other alkaloids	Caffeine	Ethanol extraction	Reduce caspase-3 and β-secretase	[80]
	Isorhynchophylline	70% ethanol reflux extraction	Down-regulate GSK-3β activity and activation of PI3K/Akt signaling pathway	[79, 81, 82]