Table 4.

Different phytochemicals for memory improvement.

Sl no.	Chemical compound	Source plant	In vivo study model	Biological effect and target	Reference
1	l-Ascorbic acid (23)	Citrus fruits	Scopalamine and Diazepam-induced young animals, Aged mice	•Improve learning ability in aged mice •Reduce transfer-latency and increase step-down latency •Protect gainst scopolamine- and diazepam-induced memory impairments	(Parle and Dhingra, 2003)
2	Bacosides (24)	Bacopa monnieri	Elderly people (65 years or older) without clinical sign of dementia in double-blind, placebo-controlled clinical trial	•Enhanced auditory verbal learning and word recall •Effective in patients with AD	Kumar et al., 2012a, Kumar et al., 2012b
3	Curcuminoids (25)	Curcuma longa	Abeta-peptide infused rat models of AD	•Positive effect on rats displayning AD-like meuronal loss •Increased PSD-95 expression in hippocampus •Increased synaptophysin expression	Ahmed et al., 2010
4	Dehydroevodiamine (26)	Evodia rutaecarpa	Rats with Scopalamine-induced memory deficit	•Inhibited acetylcholinesterase activity •Reversed sopalamine-induced memory impairments	Park et al., 1996
5	Dendrobium alkaloids (27)	Dendrobium moniliforme	Rats with LPS-induced memory deficit	•Improved neurobehavioral performance •Protection against LPS-induced memory impairments	Li et al., 2010
6	Epigallocatechin-3-gallate (EGCG, 12)	Camellia sinensis	Mice	•Boosts neurogenesis in brain areas important for memory (e.g., hippocampus)	Weatherby, 2012
7	Ginkgolides (28)	Ginkgo biloba	Patients with dementia of AD type and multi-infract dementia	•Improved task assessing speed for processing ability •Might improve cognitive process in older adults	Kumar et al., 2012a, Kumar et al., 2012b
8	Ginsenosides (29):Rg1 (20), Rg2 (21), Rg3 (30), Rb1 (19), Rh2 (22), etc.	Panax ginseng	Healthy and young volunteers	•Improvement in speed of performing memory task and accuracy of attentional task	Kumar et al., 2012a, Kumar et al., 2012b
9	Huperzine A (15)	Huperzia serrata	Individuals with AD	•Improved cognition, mood and behaviour of patients with AD	Kumar et al.,2012
10	Loganin (17)	Cornus officinalis	Scopalamine-induced amnesic mice	•Significant mitigation in scopolamine-induced memory deficits in passive avoidance test •Inhibition of acetylcholinesterase activity in mouse hippocampus	Lee K.Y et al.,
11	Nobiletin (18)	Aurantii nobilis	Mice	•Reduced memory impairment in fear conditioning •Reduced Abeta deposit in mice hippocampus	Yamakuni et al., 2010
12	Phosphatidyl choline (31)	• Allium sativum •Soy bean •Lettuce •Whole grain •Cauliflower	Human	•Enhance healing of brain tissue and nerves •Increase level of acetylcholine in brain •Useful for AD and bipolar depression	Rathee et al., 2008
13	Piperine (32)	Piper nigrum	Adult male Wistar rats	•Improve memory impairment •Reduced neurodegeneration in hippocampus •Showed neurotrophic effect in hippocampus	Chonpathompikunlert et al., 2010
14	Polygala saponins XXXII (PGS32, 33)	Polygala tenuifolia	Mice with scopalalmine-induced cognitive impairment	•Reverse Abeta-induced memory impairment through its anti-oxidative property •Reversed scopolamine effect by improving synaptic transmission •Enhancement of brain derived neurotropic factor level	Kumar et al., 2012a, Kumar et al., 2012b
15	Pseudocoptisin (34)	Corydalis tuber	Mice with scopolamine-induced memory impairrment	•Has anti-cholinesterase and anti-amnesic activity •Reversed cognitive impairments in PA test •Reduced escape latencies	Hung et al., 2008
16	Oroxylin A (35)	Scutellaria bicalensis	Rats with 2VO-induced memory impairments	•Reversed 2VO-induced memory impairments •Reduction in activated microgila •Increased BDNF expression and CREB phosphorylation	Kim et al., 2006
17	Sauroine (36)	Huperzia sqururus	Male Wistar rats	•Improved memory retention in step-down test •Increased hippocampal plasticity	Vallejo et al., 2009
18	Sesquiterpene lactone (37)	Amberboa ramosa		•Inhibits acetyl-cholinesterase and butyl-cholinestearse enzymes	Ibrahim et al., 2013