Promising Therapeutics with Natural Bioactive Compounds for Improving Learning and Memory — A Review of Randomized Trials

Abstract

Cognitive disorders can be associated with brain trauma, neurodegenerative disease or as a part of physiological aging. Aging in humans is generally associated with deterioration of cognitive performance and, in particular, learning and memory. Different therapeutic approaches are available to treat cognitive impairment during physiological aging and neurodegenerative or psychiatric disorders. Traditional herbal medicine and numerous plants, either directly as supplements or indirectly in the form of food, improve brain functions including memory and attention. More than a hundred herbal medicinal plants have been traditionally used for learning and memory improvement, but only a few have been tested in randomized clinical trials. Here, we will enumerate those medicinal plants that show positive effects on various cognitive functions in learning and memory clinical trials. Moreover, besides natural products that show promising effects in clinical trials, we briefly discuss medicinal plants that have promising experimental data or initial clinical data and might have potential to reach a clinical trial in the near future.

Extract of Caragana sinica as a potential therapeutic option for increasing alpha-secretase gene expression

“…Western medicine also shows increasing interest in novel lead compounds isolated from traditionally used medicinal plants (reviewed in Kumar et al 2012).…”

“…The use of substances from traditional medicine as novel drug libraries resembles an innovative way of finding therapeutics (Appleby and Cummings 2013). Numerous natural products have already been used traditionally as memory enhancers and preventers of senescence-induced cognitive decline (summarized in Kumar et al 2012). Galantamine for example is an alkaloid derivative isolated from members of the Amaryllidaceae family which proved to exhibit behavioral benefits (for a contemporary metaanalysis see Tan et al 2014).…”

Scopolamine induced behavioral and biochemical modifications and protective effect of Celastrus paniculatous and Angelica glauca in rats

“…[26] The use of herbal and natural extract in the treatment of neurological, psychiatric and neurotoxicological disorders has been increased tremendously due to their no or less side-effects. [23,[27][28][29] Angelica glauca, is a high value medicinal and aromatic plant species of the Himalayan region, traditionally used for treatment of migraine, nervous tension and stress. [30,31] Besides it has also been used traditionally as anti-inflammatory, diuretic, expectorant and diaphoretic and remedy for influenza, hepatitis, chronic bronchitis, rheumatism, and diseases of the urinary system.…”

Review on Ethnomedicinal uses of Memory Boosting Herb, Butterfly Pea, <i>Clitoria ternatea</i>

“…Petroleum ether extract contains fats and fixed oil while aqueous extract contains amino acids, tannins (condensed and pseudo tannins) and starch [5]. IR has been reported to possess various pharmacological actions, mainly antidiabetic [6], antiinflammatory [7], nephroprotective [8], antibacterial [9], antioxidant and antimicrobial activity [10]. Further, the principle constituents of IR such as sinapic and ferulic acids have exhibited behavioural and pharmacological…”