Greek Mountain Tea
- The acute and chronic cognitive and cerebral blood flow effects of a Sideritis scardica (Greek mountain tea) extract: a double blind, randomized, placebo controlled, parallel groups study in healthy humans.
Background: The presence of polyphenols such as hydroxy-cinnamic acids and flavonoids in Sideritis scardica (Greek mountain tea) are likely responsible for the cognitive and mood effects of its consumption and this could be underpinned by the ability of such polyphenols to prevent monoamine neurotransmitter reuptake and to increase cerebral blood flow (CBF).
Objective: The current study extends the small amount of Sideritis scardica literature in humans by assessing both cognitive and mood outcomes in a sample of older adults, as well as blood pressure (BP) and CBF, in a subsample, utilizing near-infrared spectroscopy (NIRS).
Design: This randomized, double-blind, placebo-controlled, parallel groups trial randomized N = 155, 50–70-year-old male and female participants who were assessed for the cognitive (N = 140), mood (N = 142), BP (N = 133) and CBF (N = 57) effects of two doses of Greek mountain tea (475 and 950 mg) as well as an active control of 240 mg Ginkgo biloba, and a placebo control, following acute consumption (Day 1) and following a month-long consumption period (Day 28).
Results: Relative to the placebo control, 950 mg Greek mountain tea evinced significantly fewer false alarms on the Rapid Visual Information Processing (RVIP) task on Day 28 and significantly reduced state anxiety following 28 days consumption (relative also to the active, Ginkgo control). This higher dose of Greek mountain tea also attenuated a reduction in accuracy on the picture recognition task, on Day 1 and Day 28, relative to Ginkgo and both doses of Greek mountain tea trended towards significantly faster speed of attention on both days, relative to Ginkgo. Both doses of Greek mountain tea, relative to placebo, increased oxygenated haemoglobin (HbO) and oxygen saturation (Ox%) in the prefrontal cortex during completion of cognitively demanding tasks on Day 1. The higher dose also evinced greater levels of total (THb) and deoxygenated (Hb) haemoglobin on Day 1 but no additional effects were seen on CBF on Day 28 following either dose of Greek mountain tea. Ginkgo biloba led to lower levels of Ox% and higher levels of Hb on Day 1 and lower levels of both HbO and THb on Day 28.
Conclusions: The significantly improved cognitive performance following Greek mountain tea on Day 1 could be due to significant modulation of the CBF response. However, these improvements on Day 28 are more likely to be due to the reductions in state anxiety and, taken together, suggests that the former mechanism is more likely to facilitate acute cognitive effects and the latter more likely to underpin more prolonged cognitive improvements. [Wightman EL, Jackson PA, Khan J, et al. The acute and chronic cognitive and cerebral blood flow effects of a Sideritis scardica (Greek mountain tea) extract: a double blind, randomized, placebo controlled, parallel groups study in healthy humans. Nutrients. 2018;10:955.] - Effect of an herbal extract of Sideritis scardica and B-vitamins on cognitive performance under stress: a pilot study.
Chronic stress can impair cognitive functions including learning and memory. The current study investigated the reduction of (mental) stress and improvement of stress tolerance in 64 healthy men and women after six weeks intake of a dietary supplement containing an extract of Sideritis scardica and selected B-vitamins. Mental performance and visual attention were measured by Trail-Making Test (TMT) and Colour-Word-Test (CWT)before/after an acute stress stimulus (noise, CW-Interference). TMT improved upon product intake. The CWT reaction time accelerated upon product intake in situations of CW-Congruence (overall) (p=0.014), CW-conflict (overall) (p=0.024), CW-conflict (with noise) (p=0.001), CW-Congruence (without noise) (p=0.004) and CW-conflict (without noise) (p=0.017).CWT-changes upon product intake, differentiated for noise and CW-interference, showed (i) a bisection of CW-interference-related impairment of the reaction time in the presence of noise from 27 ms to 13.5 ms, (ii) a bisection of noise-related impairment of the reaction time in the presence of CW-conflict from 34 ms to 17 ms, (iii) an improvement of the impairment of the reaction time due to combined stress (noise plus CW-conflict) by 14.5 ms from 66 ms to 51.5 ms, (iv) despite of the improvement of the reaction time, no increase of the error rate. Safety blood parameters and the reporting of no adverse events argue for the product’s safety. These results may be relevant for persons solving cognitive tasks under conflict and/or noise (e.g. open-plan offices or car-driving) and support that the tested product alleviates stress-induced impairment of executive functioning (working memory, cognitive flexibility, controlled behavioural inhibition). [Behrendt I, Schneider I, Schuchardt JP, Bitterlich N, Hahn A. Effect of an herbal extract of Sideritis scardica and B-vitamins on cognitive performance under stress: a pilot study. Int J Phytomed. 2016;8:95-103. - Psychophysiological effects of Sideritis and Bacopa extract and three combinations thereof – a quantitative EEG study in subjects suffering from mild cognitive impairment (MCI).
Mild cognitive impairment (MCI) is regarded as a transitional stage during the development of Alzheimer’s disease. Diagnosis of MCI can be obtained by the questionnaire “DemTect” in German speaking countries. Quantitative assessment has been successfully performed using psychometric testing concomitantly with quantitative EEG recording. The present investigation aimed at the possible treatment of MCI with two botanicals, namely extracts from Sideritis scardica (500 mg) or Bacopa monnieri (320 mg) and three combinations thereof using this method in order to find a new treatment. The performance of the d2-test, an arithmetic calculation test (CPT) and a memory-test revealed better performance for the d2-test only in the presence of Sideritis extract or the combinations with Bacopa extract. Quantitative EEG assessment during the different experimental conditions showed massive differences between both extracts. Whereas Sideritis extract and its combination with a low amount of Bacopa extract (160 mg) induced increases of spectral power in fronto-temporal brain areas, Bacopa and the combination of Sideritis with high amounts of Bacopa extract produced attenuation of all waves except for delta in fronto-temporal brain areas. These differences were also documented by quantitative EEG maps in comparison to Placebo. A different action of both extracts was confirmed by discriminant analysis, where Sideritis extract and its combination with low Bacopa grouped together quite at distance to Bacopa and the combination of Sideritis with high Bacopa. A combination of Sideritis extract with a low amount of Bacopa should be tested with daily repetitive dosing for at least 4 weeks as a consequence. [Dempfel W, Schombert L, Biller A. Psychophysiological effects of Sideritis and Bacopa extract and three combinations thereof – a quantitative EEG study in subjects suffering from mild cognitive impairment (MCI). Adv Alz Dis. 2016;5:1-22. - Psychophysiological effects of a combination of Sideritis and Bacopa extract in 32 patients suffering from mild cognitive impairment. A double-blind, randomized, placebo-controlled, 2-armed study with parallel design.
Mild cognitive impairment (MCI) can be regarded as a non-demented transitional stage during the development of Alzheimer’s disease. Early recognition of this stage might increase the chance of prevention by early treatment. Within a pilot study, two plant-derived preparations and mixtures thereof were tested successfully in subjects suffering from MCI. A combination of Sideritis scardica and Bacopa monnieri extract (memoLoges®) was chosen now for a repetitive dosing during 4 weeks. Thirty-two subjects aged 50 to 80 years and suffering from MCI (having a DemTect questionnaire score between 8 and 13) were recruited for intake of 2 capsules of the preparation per day. Quantitative EEG recording during relaxation and concomitant performance of three 5 minutes lasting psychometric tests (d2-concentration test, arithmetic calculation test and memory test) was achieved at the first day and one day after the last repetitive intake. Seventeen channels of EEG and one channel EOG (for artefact rejection) were recorded. After frequency analysis (FFT) current source density was calculated as reported earlier. One, two and three hours after intake of the herbal extract or placebo the whole procedure was repeated. Brain imaging was achieved by conversion of numerical values of spectral EEG power into spectral colors and additive color mixture according to RGB as used in TV settings. Intake of memoLoges® induced a trend of improvement of performance in psychometric testing (all three tests). During relaxation quantitative as sessment of EEG data revealed attenuation of delta and theta spectral power in frontal brain as likewise reported in the presence of the Alzheimer drug rivastigmine, bringing the spectrum back to “normality”. During mental work memoLoges® induced statistically significant increases of beta power. Since MCI subjects produce less beta power in comparison to healthy subjects, this increase must likewise be seen as a positive effect pointing to a healthier spectrum. [Dimpfel W, Biller A, Suliman S, Dipah GNC. Psychophysiological effects of a combination of Sideritis and Bacopa extract in 32 patients suffering from mild cognitive impairment. A double-blind, randomized, placebo-controlled, 2-armed study with parallel design. Adv Alz Dis. 2014;5:103-125. - Assessment of the acute and subchronic toxicity and mutagenicity of Sideritis scardica Griseb. extracts.
Sideritis scardica Griseb. has a long history of collection from the wild as a traditional remedy for respiratory and gastrointestinal complaints. It has also been investigated for its promising pharmacological activities in the central nervous system. However, its toxicological data is entirely missing. This study investigated the acute and repeated-dose oral toxicity of a S. scardica 20% (v/v) ethanol extract in Sprague Dawley rats, and mutagenicity using the Ames test. No gross pathological abnormalities and no toxicity signs or mortality were detected in animals treated with the dose of 2000 mg/kg bw during 14 days of observation. The tested extract was assigned to category 5 of the GHS. To evaluate a repeated-dose toxicity, an extract has been tested over a 28-day period followed by a 14-day recovery period. No mortality and no changes in body/organ weight or food consumption have been observed. The no-observed-adverse-effect-level of the extract was determined at 1000 mg/kg bw. The results of Ames tests conducted on extracts of different polarity (water; 20% (v/v) ethanol; 50% (v/v) ethanol; n-heptane), were unequivocally negative. The study reveals no toxicity of S. scardica and no concerns for its mutagenic effects, supports its positive safety profile, and confirms the acknowledged traditional medicinal use in human. [Feistel B, Wegener T, Rzymski P, Pischel I. Assessment of the acute and subchronic toxicity and mutagenicity of Sideritis scardica Griseb. extracts. Toxins. 2018;10:258.] - Siteritis scardica extracts inhibit aggregation and toxicity and amyloid-ß in Caenorhabditis elegans used as a model for Alzheimer’s disease.
Background. Beyond its traditional uses in the Balkan area, Sideritis scardica (known as Greek mountain tea, Lamiaceae) is currently extensively investigated for its pharmacological activity in the central nervous system. Antidepressant, psychostimulating, cognition-enhancing and neuroprotective properties have been described. In this study, we tested hydroalcoholic extracts of S. scardica for their potential to counteract amyloid- _ toxicity and aggregation, which plays a crucial role in the pathogenesis of Alzheimer’s disease.
Methods. For this purpose, we have chosen the nematode Caenorhabditis elegans, which is used as a model organism for neurodegenerative diseases. The concentration of different polyphenols in extracts prepared from water, 20, 40, 50, and 70% ethanol was analysed by HPLC. Additionally, polar and unpolar fractions were prepared from the 40% ethanolic extract and phytochemically analyzed.
Results. Essentially, the contents of all measured constituents increased with the lipophilicity of the extraction solvents. Treatment of transgenic C. elegans strains expressing amyloid-_ with the extracts resulted in a reduced number of peptide aggregates in the head region of the worms and alleviated toxicity of amyloid-_, observable through the degree of paralysed animals. The mid-polar extracts (40 and 50% ethanol) turned out be the most active, decreasing the plaque number by 21% and delaying the amyloid-_-induced paralysis by up to 3.5 h. The more lipophilic extract fractions exhibited higher activity than the hydrophilic ones. Discussion. Sideritis scardica extracts demonstrated pharmacological activity against characteristics of Alzheimer’s disease also in C. elegans, supporting current efforts to assess its potential for the treatment of cognitive decline. The active principle as well as the mode of action needs to be investigated in more detail. [Heiner F, Feister B, Wink M. Siteritis scardica extracts inhibit aggregation and toxicity and amyloid-ß in Caenorhabditis elegans used as a model for Alzheimer’s disease. PeerJ. 2018;6:e4683.] - Sideritis spp. extracts enhance memory and learning in Alzheimer’s ß-amyloidosis mouse models and aged C57B1/6 mice.
Abstract. Nowadays, Alzheimer’s disease is the most prevalent epiphenomenon of the aging population. Although solubleamyloid- ß (Aß) species (monomers, oligomers) are recognized triggers of the disease, no therapeutic approach is able to stop it. Herbal medicines are used to treat different diseases in many regions of the world. On the Balkan Peninsula, at the eastern Mediterranean Sea, and adjacent regions, Sideritis species are used as traditional medicine to prevent age-related problems in elderly. To evaluate this traditional knowledge in controlled experiments, we tested extracts of two commonly used Sideritis species, Sideritis euboea and Sideritis scardica, with regard to their effects on cognition in APP-transgenic and aged, nontransgenic C57Bl/6 mice. Additionally, histomorphological and biochemical changes associated with Aß deposition and treatment were assessed. We found that daily oral treatment with Sideritis spp. extracts highly enhanced cognition in aged, non-transgenic as well as in APP-transgenic mice, an effect that was even more pronounced when extracts of both species were applied in combination. The treatment strongly reduced Aß 42 load in APP-transgenic mice, accompanied by increased phagocytic activity of microglia, and increased expression of the _-secretase ADAM10. Moreover, the treatment was able to fully rescue neuronal loss of APP-transgenic mice to normal levels as seen in non-transgenic controls. Having the traditional knowledge in mind, our results imply that treatment with Sideritis spp. extracts might be a potent, well-tolerated option for treating symptoms of cognitive impairment in elderly and with regard to Alzheimer’s disease by affecting its most prominent hallmarks: Aß pathology and cognitive decline. [Hofrichter J, Krohn M, Schumacher T, et al. Sideritis spp. Extracts enhance memory and learning in Alzheimer’s ß-amyloidosis mouse models and aged C57B1/6 mice. J Alz Dis. 2016;53:967-980.] - Greek mountain tea – an herbal drug for mental enhancement.
Herein an electroencephalographic pharmacogram (EEGP) was prepared in an animal model to detect possible psychopharmacological effects. Animals were exposed to extract of Sideritis aquos. sicc. within a crossover design vs. placebo. Single dosages were administered once a week. Strongest effects were seen with respect to alpha2 waves representing an activation of dopaminergic neurotransmission. Delta, theta, and especially at higher dosages alpha1 waves were also attenuated, compatible with the view of activation of the cholinergic, norepinephrinergic and serotonergic transmission systems. Strongest effects were always observed in the frontal cortex followed by the hippocampus. These brain areas are heavily involved in cognitive functioning. Therefore, it can be expected, that the administration of this extract also would improve mental performance. [Walbroel B, Feistel B. Greek mountain tea – an herbal drug for mental enhancement. Poster presentation. 58th International Congress and Annual Meeting of the Society for Medicinal Plant and Natural Product Research. August 29- September 2, 2010. Berlin, Germany.
