The polyphenols in spearmint extract have a neuroprotective effect in the brain, of which rosmarinic acid (RA) accounts for a high proportion of spearmint. Studies have demonstrated that RA is a phenolic compound with powerful antioxidant and anti-inflammatory activities that has a neuroprotective effect in animal models of neurodegenerative diseases such as Alzheimer's and Parkinson's disease and ischemia-reperfusion models. So how does it provide neuroprotective effects?
Oxidative stress and neuroinflammation play a key role in brain diseases, and they further lead to neurodegenerative diseases. In a 2008 trial published in the journal Toxicology Research, researchers found that rosmarinic acid significantly reduced H2O2-induced reactive oxygen production and apoptosis, and also effectively inhibited the upregulation of Bax and the downregulation of Bcl-2. The latest study from 2020 also showed that rosmarinic acid improves memory and behavioral disorders in mice by alleviating oxidative stress and acetylcholinesterase activity. Rosemary acid can rejuvenate elevated pro-inflammatory cytokines and apoptotic proteins, as well as restore antioxidant defense levels and reduce lipid peroxidation levels.
Not only that, but a research team at the University of Tokyo in Japan also discovered the anti-inflammatory effects of rosemary acid. Using mice as model organisms, the researchers found that the accumulation of Aβ plaques and tau in mice taken rosemary in the cortex region near the amygdala and hippocampus was inhibited, and the JNK signaling pathway in inflammation in the hippocampus was also suppressed, reducing inflammation levels.
Rosmarinic acid plays a beneficial role in the pathogenesis of neurodegenerative diseases by regulating pathways such as inflammation and oxidative stress. In addition, numerous research data show that it also has the effect of improving cognition, which can both anti-inflammatory and antioxidant and promote intellectual awareness.
【Reference】
Yamamoto S, Kayama T, Noguchi-Shinohara M, et al. Rosmarinic acid suppresses tau phosphorylation and cognitive decline by downregulating the JNK signaling pathway[J]. NPJ science of food, 2021, 5(1): 1-11.
Thingore C, Kshirsagar V, Juvekar A. Amelioration of oxidative stress and neuroinflammation in lipopolysaccharide-induced memory impairment using Rosmarinic acid in mice[J]. Metabolic Brain Disease, 2021, 36(2): 299-313.
Fonteles A A, de Souza C M, de Sousa Neves J C, et al. Rosmarinic acid prevents against memory deficits in ischemic mice[J]. Behavioural Brain Research SreeTestContent1, 2016, 297: 91-103.
Lee H J, Cho H S, Park E, et al. Rosmarinic acid protects human dopaminergic neuronal cells against hydrogen peroxide-induced apoptosis[J]. Toxicology, 2008, 250(2-3): 109-115.