Therapeutic Potential of Active Components from Acorus gramineus and Acorus tatarinowii in Neurological Disorders and Their Application in Korean Medicine

Abstract

Neurological disorders represent a substantial healthcare burden worldwide due to population aging. Acorus gramineus Solander (AG) and Acorus tatarinowii Schott (AT), whose major component is asarone, have been shown to be effective in neurological disorders. This review summarized current information from preclinical and clinical studies regarding the effects of extracts and active components of AG and AT (e.g., α-asarone and β-asarone) on neurological disorders and biomedical targets, as well as the mechanisms involved. Databases, including PubMed, Embase, and RISS, were searched using the following keywords: asarone, AG, AT, and neurological disorders, including Alzheimer's disease, Parkinson's disease, depression and anxiety, epilepsy, and stroke. Meta-analyses and reviews were excluded. A total of 873 studies were collected. A total of 89 studies were selected after eliminating studies that did not meet the inclusion criteria. Research on neurological disorders widely reported that extracts or active components of AG and AT showed therapeutic efficacy in treating neurological disorders. These components also possessed a wide array of neuroprotective effects, including reduction of pathogenic protein aggregates, antiapoptotic activity, modulation of autophagy, anti-inflammatory and antioxidant activities, regulation of neurotransmitters, activation of neurogenesis, and stimulation of neurotrophic factors. Most of the included studies were preclinical studies that used in vitro and in vivo models, and only a few clinical studies have been performed. Therefore, this review summarizes the current knowledge on AG and AT therapeutic effects as a basis for further clinical studies, and clinical trials are required before these findings can be applied to human neurological disorders.

New Value of Acorus tatarinowii/gramineus Leaves as a Dietary Source for Dementia Prevention

“…To identify the ingredients that meet these requirements, we explored the medicinal herbs used in traditional Chinese medicine. Several herbs have been reported to have beneficial effects on amnesia, including Rehmanniae radix [ 31 ], Polygalae radix [ 32 ], Zizyphi spinosi semen [ 33 ], and ATR/AGR [ 10 , 11 , 12 ]. When considering these herbs as foodstuffs, we need to be especially careful about their safety because they will be consumed for a long period.…”

“…While our study suggests several advantages of multi-ingredient diets, the identification of the active components in ATL/AGL would facilitate the development of pharmaceuticals for treating neurodegenerative diseases. ATR and AGR are known to contain various ingredients [ 10 , 11 , 12 ], among which α-asarone and β-asarone have been well studied [ 13 ] and are reported to improve cognition in animal models of neurodegenerative dementia. For example, oral administration of α-asarone improves cognition in Aβ25-35-injected rats by reducing nitric oxide levels [ 14 ].…”

“…However, some studies have revealed the possible toxicity of α- and β-asarone in chronic administration to animals [ 44 , 45 ]. In addition, Acorus gramineus and Acorus tatarinowii contain more than 160 compounds of different structural types, including phenylpropanoids, terpenoids, lignans, flavonoids, alkaloids, amides, organic acids, and others [ 10 , 11 , 12 ]. These compounds are thought to work together to exert the medicinal effects of the plants, but some of them may be toxic at a high concentration.…”

“…They belong to the genus Acorus and have similar morphological characteristics in their aerial parts (i.e., leaves) and rhizomes [ 9 ]. Their rhizomes, Acorus tatarinowii rhizome (ATR) and Acorus gramineus rhizome (AGR), are widely used for amnesia in traditional Chinese medicine [ 10 , 11 , 12 ]; ATR is used in China, and AGR is used in Japan [ 9 ]. In contrast, their leaves, referred to as Acorus tatarinowii leaf (ATL) and Acorus gramineus leaf (AGL), are seldom used in traditional Chinese medicine and are usually discarded without their medicinal properties being known.…”

“…In Japan, the rhizomes are treated as pharmaceuticals, whereas the leaves are regarded as non-pharmaceuticals (i.e., treatable as foodstuffs). The rhizomes contain various ingredients [ 10 , 11 , 12 ], and α-asarone and β-asarone are the main active components that have been shown to improve cognition in mice and rats [ 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. We speculated that the leaves may contain some active ingredients similar to the rhizomes; therefore, we compared their effects on mouse cognition.…”