Херициум-МРЛ - профилирање на централниот нервен систем - Клинички журнал на микологија - јан 2022

Central Nervous System Profiling of Hericium erinaceus Biomass Powder by an Electropharmacogram Using Spectral Field Power in Conscious Freely Moving Rats - Clinical Journal of Mycology, Jan 2022

SUMMARY

Mushroom extracts seem to exert an action on brain function. In order to objectify such an effect changes of the electric activity of the brain have been successfully used in earlier experiments in the presence of diverse food extracts.

Changes of field potentials recorded from implanted electrodes into the depth of the brain of rats served to analyse the action of plant-derived extracts in comparison to food supplements and reference drugs. Frequency analysis of the data and feeding of the results into discriminant analysis allowed indication dependent classification of the effects. The present investigation aimed at the neuro-physiological characterization of the effect of a preparation of Hericium erinaceus in this model.

The presently tested mycological preparation “MRL’s Hericium erinaceus hyphal powder” induced a pattern of frequency changes consisting in a statistically significant attenuation of delta, theta, alpha2 and beta1 spectral power, but not alpha1 power in all brain regions during the first 2 hours after administration. The lack of alpha1 spectral power attenuation in combination with attenuation of delta, theta and alpha2 power is shared by some other preparations tested earlier under identical conditions like Zembrin®, Acetylsalicylic acid, Methylphenidate, Taxifolin and Ginkgo extract. From this, calming, analgesic, antidepressive and cognition enhancing properties might be deduced for the tested mushroom biomass. However, due to the fact, that only one dosage was tested, interpretation of the results is limited. As active ingredients recently discovered erinacines from Hericium ericaneus mycelia might be considered, which show up in the brain as early as 30 min after oral administration.

INTRODUCTION

Drugs, food supplements and functional food exert their action within the organism by interaction with targets defined biochemically (e.g. receptors, enzymes, channels transporters, large protein molecules sometimes also sitting at the outer surface of cells). With respect to the central nervous system neurotransmitter receptors represent main targets. Interaction of drugs with these molecules induces a signalling cascade, which finally ends up with the control of ion channel conductance. Since the electric activity of single neurons depends on the set of momentarily active ion channels, communication between neurons is governed by channel activity. From here, it is obvious that field potentials contain the information of larger local networks of electrically active neurons, by it reflecting the interaction of externally administered molecules with their targets within the concert of neurotransmission.

Frequency analysis of the field potentials in the presence of drugs leads to the so-called electropharmacogram, which has been widely used in the past to characterize drug actions on rat (Dimpfel, 2007) and human brains (Dimpfel, 2011)(Dimpfel, 2015). Interpretation of the results was performed with respect to neurotransmitter activity as well as aiming at possible clinical indications in humans. A relation between EEG delta waves and cholinergic neurotransmission has been suggested for the first time by Dimpfel (Dimpfel, 2005). Theta waves have been recognized as being influenced by drugs acting at the biochemically defined norepinephrine alpha2 receptor (Dimpfel & Schober, 2001). Presynaptic interaction with this receptor leads to drowsiness and sleep and increases of theta waves have been used as part of a formula describing depth of sleep in humans (Dimpfel et al., 1989). Dopaminergic activity is reflected by changes in alpha2 frequencies (Dimpfel, 2008). Drug induced changes in the beta1 frequency domain relate to glutamatergic transmission, whereas drugs acting at GABA receptors induce increases in beta2 frequencies.

Hericium erinaceus (Bull.: Fr.) Pers. is an edible and medicinal basidiomycete fungus belonging to the class Agaricomycetes, order Russulales and family Agaricomycetes (Kirk et al. 2008). It is commonly known as Shishigashira or Houtou (meaning “monkey head”) in China and Yamabushitake (meaning “mountain priest”) in Japan. English names for the fungus include Lion’s Mane, Monkey’s Mushroom, Bear’s Head, Hog’s Head Fungus, White Beard, Old Man’s Beard and Pom Pom (Thongbai et al., 2015). The fruiting body has historically been prescribed as part of traditional Chinese medicine (TCM) and Kampo medicine in Japan, including for treating neurasthenia and general debility (Ying et al., 1987).

Hericium is found across the northern hemisphere in Asia, Europe and North America (Thongbai et al., 2015). In recent years the fruiting bodies and cultured mycelia of Hericium have become increasingly popular in North America and Europe in the form of nutraceuticals and food supplements for improving health and well-being, including for enhancing cognitive function. Hericium fruiting bodies and mycelium can be grown on industrial scale on diverse substrates, including inexpensive agricultural wastes. Both the fruiting body and the cultured mycelia have been reported to produce several classes of bioactive molecules, including polysaccharides, proteins, lectins, sterols, phenols, and terpenoids (Thongbai et al., 2015).

The following in vitro, in vivo and human clinical studies have demonstrated that powders, extracts and fractions of Hericium have activities on the central and peripheral nervous systems: In vitro studies Secretion of nerve growth factor (NGF) from astrocytes has been noted to be increased with 150µg/mL of the ethanolic extract. Lion’s Mane has been noted to increase mRNA expression of NGF in isolated astrocytes to around 5-fold that of control at 100-150µg/mL.

In vitro studies

Secretion of nerve growth factor (NGF) from astrocytes has been noted to be increased with 150µg/mL of the ethanolic extract. Lion’s Mane has been noted to increase mRNA expression of NGF in isolated astrocytes to around 5-fold that of control at 100-150µg/mL of ethanolic extract in a concentration dependent manner (Mori et al., 2008). Isolated erinacines (A-C), present in the mycelium, are known to stimulate NGF secretion at 1mM concentrations (Kawagishi et al., 1994). Glutamate neuronal excitability appears to be attenuated in the presence of Hericium extracts in vitro (Moldavan et al., 2007).

In vivo studies

An increase in NGF mRNA has been detected in the hippocampus, but not cortex, of mice given 5% of the diet as lion’s mane for a period of seven days to around 1.3-fold of control (Mori et al., 2008). Hericium appears to protect rats against cognitive decline caused by β-amyloid pigmentation at 5% of the diet (Mori et al., 2011).

In an in vivo study in rats, Hericium aqueous extract of fruiting body was able to promote neuronal regrowth after crushing injury to the gluteal nerve. Rats that had induced gluteal nerve damage were able to walk better after ingestion of the extract (Wong et al., 2011). Compared with saline-treated mice, dietary administration of Hericium ethanolic fruit body extracts at 60 mg/kg once a day for 4 weeks reduced anxiety and depressive-like behaviour in healthy mice assessed through elevated plus-maze, tail-suspension and forced swimming tests. This was associated with increased proliferation of hippocampal progenitors and enhanced neurogenesis (Ryu et al., 2018). 

Antidepressant-like effects of ethanolic extract of Hericium mycelium enriched in erinacine A were studied in depressive mice challenged by repeated restraint stress (RS) . The extract at 100, 200 or 400 mg/ kg body weight/day was orally given to mice for 4 weeks. After 2 weeks of Hericium administration, all mice except the control group went through with 14 days of RS protocol. Stressed mice exhibited behavioural alterations, including extended immobility time in the tail suspension test (TST) and forced swimming test (FST), and increasing the number of entries in open arm (POAE) and the time spent in the open arm (PTOA). The levels of norepinephrine (NE), dopamine (DA) and serotonin (5-HT) were decreased in the stressed mice, while the level-s of interleukin (IL)-6 and tumour necrosis factor (TNF)-α were increased. These changes were significantly reversed by the administration of Hericium extract, especially at the dose of 200 or 400 mg/kg body weight/day. Additionally, the extract was shown to activate the BDNF/TrkB/PI3K/Akt/GSK-3β pathways and block the NF-κB signals in mice. Taken together, this erinacine A-enriched Hericium mycelium extract could reverse the depressivelike behaviour caused by induced RS and was accompanied by the modulation of monoamine neurotransmitters as well as proinflammatory cytokines, and regulation of BDNF pathways. Thus the erinacine A-enriched Hericium mycelium extract has potential for the treatment of depressive disorders (Chiu et al., 2018). Hericium extracts with known amounts of erinacine A and hericenones C and D were tested in a frail mouse model of physiological aging. 

Two-months oral supplementation with Hericium reversed the agerelated decline in recognition memory. Proliferating cell nuclear antigen (PCNA) and doublecortin (DCX) immunohistochemistry in the hippocampus and cerebellum in treated mice supported a positive effect of the extract on neurogenesis in frail mice (Ratto et al., 2019).

Clinical studies

A double-blind, parallel-group, placebo-controlled trial performed on 50 to 80 year old Japanese men and women diagnosed with mild cognitive impairment, 30 subjects were randomized into two 15 person groups. The subjects of the active group took four 250 mg tablets containing 96% of Hericium hyphal and dry powder 3 times a day for 16 weeks. After termination of the intake, the subjects were observed for the next 4 weeks. At weeks 8, 12 and 16 of the trial, the Hericium group showed significantly increased scores on the cognitive function scale compared with the placebo group; at week 4 after the termination of the 16 weeks intake, the cognitive function scores decreased significantly. The results indicated that Hericium is well tolerated, and improves mild cognitive impairment (Mori et al., 2009).

A recent study carried out on 77 overweight or obese volunteers reported that a daily, 8-week oral supplementation with Hericium (80% mycelium extract and 20% fruiting body extract), coupled with a low calorie diet regimen improved depression, anxiety, sleep, and binge eating compared with subjects undergoing low calorie diet only. This improvement was correlated with increased circulating pro-BDNF levels and pro-BDNF/BDNF ratio, despite the lack of any significant changes in BDNF circulating levels (Vigna et al., 2019).

The present preparation consisting of mycelium powder from Hericium erinaceus biomass (Hericium-MRL) was tested as the first study in the animal model of field potential analysis in order to see whether any ingredients can pass the blood barrier and exert an activity on the electric activity of the central nervous system. The electropharmacogram of this preparation should also provide more insight into the effectiveness with respect to time dependence. Since many publications also deal with so-called EEG gamma activity -representing frequencies above 35 Hz-, this parameter was also measured. 

Conclusion: From this preliminary study in a small number of animals (n=8) it can be concluded that MRL’s Hericium erinaceus hyphal powder contains compounds that are bioavailable and cross the blood brain barrier resulting in an EEG signature that can be interpreted by discriminant analysis to have potential calming, analgesic, antidepressant and cognitive-enhancing activities. Based upon many years in the evaluation of electropharmacogram studies in both pharmaceutical and natural products, the dose of 150 mg/ kg body weight used in the present study may translate to a human dose of 15 mg/kg body weight, or 1 050 mg in a 70 kg adult, within the daily dose range of 1-3g recommended by the Sponsor (Nektium)).

AUTHORS:

Prof. Wilfried Dimpfel Justus-Liebig-University Giessen, Germany, dimpfel1945@web.de

Dr. Julie Wiebe Nektium Pharm S.L., Las Palmas, Spain, jwiebe@nektium.com

Dr. Nigel Gericke Gericke Consulting, Baden, Switzerland, nigel@drgerickeconsulting.com