Polyphenols are a large family of naturally occurring phenols. They are abundant in plants and structurally diverse. Polyphenols include flavonoids, tannic acid, and ellagitannin, some of which have been used historically as dyes and for tanning garments.
Physostigmine is a highly toxic parasympathomimetic alkaloid, specifically, a reversible cholinesterase inhibitor. It occurs naturally in the Calabar bean and the fruit of the Manchineel tree.
A natural product is a natural compound or substance produced by a living organism—that is, found in nature. In the broadest sense, natural products include any substance produced by life. Natural products can also be prepared by chemical synthesis and have played a central role in the development of the field of organic chemistry by providing challenging synthetic targets. The term natural product has also been extended for commercial purposes to refer to cosmetics, dietary supplements, and foods produced from natural sources without added artificial ingredients.
Galantamine is used for the treatment of cognitive decline in mild to moderate Alzheimer's disease and various other memory impairments. It is an alkaloid that has been isolated from the bulbs and flowers of Galanthus nivalis, Galanthus caucasicus, Galanthus woronowii, and some other members of the family Amaryllidaceae, such as Narcissus (daffodil), Leucojum aestivum (snowflake), and Lycoris including Lycoris radiata. It can also be produced synthetically.
Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is found in many fruits, vegetables, leaves, seeds, and grains; capers, red onions, and kale are common foods containing appreciable amounts of it. It has a bitter flavor and is used as an ingredient in dietary supplements, beverages, and foods.
Ellagic acid is a polyphenol found in numerous fruits and vegetables. It is the dilactone of hexahydroxydiphenic acid.
Huperzine A is a naturally occurring sesquiterpene alkaloid compound found in the firmoss Huperzia serrata and in varying quantities in other food Huperzia species, including H. elmeri, H. carinat, and H. aqualupian. Huperzine A has been investigated as a treatment for neurological conditions such as Alzheimer's disease, but a meta-analysis of those studies concluded that they were of poor methodological quality and the findings should be interpreted with caution. Huperzine A inhibits the breakdown of the neurotransmitter acetylcholine by the enzyme acetylcholinesterase. It is commonly available over the counter as a nutrient supplement, and is marketed as a cognitive enhancer for improving memory and concentration.
Lupinine is a quinolizidine alkaloid present in the genus Lupinus of the flowering plant family Fabaceae. The scientific literature contains many reports on the isolation and synthesis of this compound as well as a vast number of studies on its biosynthesis from its natural precursor, lysine. Studies have shown that lupinine hydrochloride is a mildly toxic acetylcholinesterase inhibitor and that lupinine has an inhibitory effect on acetylcholine receptors. The characteristically bitter taste of lupin beans, which come from the seeds of Lupinus plants, is attributable to the quinolizidine alkaloids which they contain, rendering them unsuitable for human and animal consumption unless handled properly. However, because lupin beans have potential nutritional value due to their high protein content, efforts have been made to reduce their alkaloid content through the development of "sweet" varieties of Lupinus.
An enzyme inhibitor is a molecule that binds to an enzyme and blocks its activity. Enzymes are proteins that speed up chemical reactions necessary for life, in which substrate molecules are converted into products. An enzyme facilitates a specific chemical reaction by binding the substrate to its active site, a specialized area on the enzyme that accelerates the most difficult step of the reaction.
Hopea chinensis is a species of medium-sized tree in the family Dipterocarpaceae. It is found in China and northern Vietnam.
Hopea hainanensis is a species of tree in the family Dipterocarpaceae. It is found in Hainan Island of China and northern Vietnam. Hopea hainanensis produces the acetylcholinesterase inhibitor Hopeahainol A.
Piceatannol is the organic compound with the formula ( 2C6H3)2CH)2. Classified as a stilbenoid and a phenol, it is a white solid, although samples often are yellow owing to impurities.
Acetylcholinesterase (HGNC symbol ACHE; EC 3.1.1.7; systematic name acetylcholine acetylhydrolase), also known as AChE, AChase or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme that catalyzes the breakdown of acetylcholine and some other choline esters that function as neurotransmitters:
Acetylcholinesterase inhibitors (AChEIs) also often called cholinesterase inhibitors, inhibit the enzyme acetylcholinesterase from breaking down the neurotransmitter acetylcholine into choline and acetate, thereby increasing both the level and duration of action of acetylcholine in the central nervous system, autonomic ganglia and neuromuscular junctions, which are rich in acetylcholine receptors. Acetylcholinesterase inhibitors are one of two types of cholinesterase inhibitors; the other being butyryl-cholinesterase inhibitors. Acetylcholinesterase is the primary member of the cholinesterase enzyme family.
Tenuazonic acid is a mycotoxin produced by Alternaria species. It is a powerful eukaryotic protein synthesis inhibitor. It is a tetrameric acid that is ubiquitous in biological environments and prevents the release of newly synthesized protein from the ribosome. Its toxicity is the highest among all Alternaria mycotoxins and has both phytotoxic and cytotoxic properties. In 1991 Tenuazonic acid was reported to inhibit skin tumor promotion in mice.
Taspine is an alkaloid which acts as a potent acetylcholinesterase inhibitor and cicatrizant. It is found in various plants including Magnolia x soulangeana and Croton lechleri.
Methanesulfonyl fluoride (MSF) has long been known to be a potent inhibitor of acetylcholinesterase (AChE), the enzyme that regulates acetylcholine, an important neurotransmitter in both the central and peripheral nervous systems.
Ungeremine is a betaine-type alkaloid isolated from Nerine bowdenii and related plants such as Pancratium maritimum. Pharmacologically, it is of interest as an acetylcholinesterase inhibitor and accordingly as possibly relevant to Alzheimer's disease. It also has been investigated as a bactericide.
Huprine X is a synthetic cholinergic compound developed as a hybrid between the natural product Huperzine A and the synthetic drug tacrine. It is one of the most potent reversible inhibitors of acetylcholinesterase known, with a binding affinity of 0.026nM, as well as showing direct agonist activity at both nicotinic and muscarinic acetylcholine receptors. In animal studies it has nootropic and neuroprotective effects, and is used in research into Alzheimer's disease, and although huprine X itself has not been researched for medical use in humans, a large family of related derivatives have been developed.
Hopeanol is a highly cytotoxic resveratrol-derivative with the molecular formula C29H20O9 which has been isolated from the bark of the tree Hopea exalata.
