Table 1.

Bioactive compounds in clinical trials for AD therapy.

Bioactive Compound	Condition of Participants	Number of Subjects	Duration	Outcomes	Ref.
Vitamin D	Mild cognitive impairment	8	8 weeks	Reduction of Aβ level	[35]
	Mild cognitive impairment and early AD	48	20 months	Reduction of Aβ level; Improvement of cognitive functions	[36]
Vitamin D and memantine	Moderate AD	43	24 weeks	Improvement of cognitive functions	[37]
Vitamin D and antioxidants	Mild to moderate AD	78	16 weeks	Reduction of oxidative stress	[38]
Vitamin E and vitamin C	AD	20	1 month	Reduction of oxidative stress	[39]
Vitamin E and selegiline	Moderate AD	341	2 years	Delay of AD progression	[40]
Vitamin E and donepezil	Mild cognitive impairment	769	5 years	No effectiveness in delaying AD progression	[41]
Vitamin E and memantine	Mild to moderate AD	613	5 years	Delay of AD progression	[42]
Vitamin E and selenium	Healthy patients	3786	13 years	No prevention of dementia	[43]
Docosahexaenoic acid (DHA) and eicosapentaenoic acid	AD	204	12 months	Safe and well tolerated; No effectiveness in delaying cognitive decline	[44]
DHA	AD	295	18 months	No effectiveness in delaying cognitive decline	[45]
	Cognitive impairments	485	24 weeks	Improvement of cognitive functions	[46]
	Mild cognitive impairment	36	1 year	Safe and well tolerated; Improvement of memory	[47]
Homotaurine	Mild to moderate AD	1052	78 weeks	Improvement of cognitive functions	[48,49]
		58	3 months	No harmful effects on vital signs; Side effects	[50]
		10	4 weeks	Improvement of the central cholinergic transmission	[51]
Huperzine A	AD	103	8 weeks	Safe and well tolerated; Improvement of memory and behaviour	[52]
		60	60 days	Safe and well tolerated; Reduction of oxidative stress	[53]
	Mild to moderate AD	177	16 weeks	Safe and well tolerated; Improvement of cognitive functions	[54]
Bryostatin	AD	9	46 weeks	Safe and well tolerated: Improvement of cognitive functions	[55]
		150	12 weeks	Improvement of cognitive functions	[56]
Melatonin	AD	150	12 weeks	Improvement of memory	[57]
		14	22 to 35 months	Improvement of cognitive functions	[58]
	Mild cognitive impairment	50	9 to 18 months	Improvement of cognitive functions	[59]
	Mild to moderate AD	80	24 weeks	Safe; Improvement of cognitive functions	[60]
Resveratrol	Mild to moderate AD	119	52 weeks	Side effects; No effectiveness in reducing biomarkers levels	[61]
		39	1 year	Safe and well tolerated; No effectiveness in treat AD	[62]
Nicotine	AD	70	2 weeks	Improvement of perceptual and visual attentional deficits	[63]
		6	9 weeks	Safe; Improvement of learning	[64]
		8	10 weeks	Improvement of attentional performance	[65]
Curcumin	AD	34	6 months	Safe and well tolerated	[66]