The study mentatpsi quoted is from
Biol Pharm Bull. 2008 Sep;31(9):1727-32:
Nerve growth factor-inducing activity of Hericium erinaceus in 1321N1 human astrocytoma cells. (
full text PDF). The relevant conclusions:
However, hericenones C, D and E did not increase NGF mRNA expression at 10—100 mg/ml in 1321N1 cells (Fig. 4). Furthermore, we failed to demonstrate that hericenones C, D, and E stimulated NGF mRNA expression in primary cultured rat astroglial cells (data not shown).
...
In conclusion, H. erinaceus contains active compounds that stimulate NGF synthesis via activation of the JNK pathway; these compounds are not hericenones.
The previous work which showed effectiveness of hericenones was performed by the Kawagishi group, and was based on rat studies. So in theory, this study could negate the relevance of those findings, because it used cultured human cells. However, it seems to challenge the validity as well, as they were unable to reproduce the earlier findings in rat cells. This seems to raise a question about methodology in one of the groups. Kawagishi et al have published over 20 papers on the subject, in some of the most eminent bio/chemistry journals, and they established the methods and reference spectra for the extraction of the compounds that were used in this study.
I don't know enough about the total functioning of the brain to answer this question: is the mechanism they studied (NGF gene expression via JNK signaling in 1321N1 cells) the only way hericenones might be able to stimulate NGF? It seems to be a necessary assumption of their conclusion. I could find no mention of it in general resources
like this; all mentions seem to be in very-specific studies like this one.
This study only examined hericenones C-E; from the
Kawagishi Townsend Letter:
Each group of hericenones, C-E and F-H, contains a characteristic alcohol site, and each hericenone contains one of three simple fatty acids. Hericenone D demonstrated the strongest stimulating activity in synthesis of NGF from [rat] astroglial cells.
Furthermore,
this 2004 study established the presence of hericenone I-J. If the human and rat mechanisms are different,
how can they say unequivocally that hericenones do not increase NGF by examining less than half of them?
As such, the notion to try and provide more of the mushrooms "active ingredients" seems a bit paradoxical in a way (in the manner that if some of the compounds do not exert the desired effect, then their inclusion is illogical).
I think it's too early to say that hericenones definitely don't have an effect on NGF, but those scientists sounded pretty sure for some reason, so I could be wrong.
But there are several other reasons to include a full spectrum of actives (assuming they cause no harm, which I could find no suggestion of). First, Lion's Mane has several other health benefits, including immuno-regulatory and anti-cancer/microbial properties [
1] [
2] [
3] and prevention of stress-induced cell death in the endoplasmic reticulum [
4] [
5] [
6]. The study in [5] demonstrated that Hericenone I was responsible for some of the ER-protective effects; none of the others studied the different compounds selectively, so it's hard to say which actives are responsible.
And a reason more relevant to the NGF issue is a conclusion from the study you posted. They find that alcoholic extract of Lion's Mane fruit bodies affects NGF, but not due to hericenones C-E (which there is too little of anyway). But the fruit body has not been shown to contain the proven active erinacines (only the mycelium (roots)). Hence, a possibility that yet-unidentified actives are increasing NGF in human cells:
Preparation of Mushroom Extracts: Fresh fruiting bodies of H. erinaceus...were lyophilized and powdered. The dry powder (5g) of mushrooms was extracted with 150ml of ethanol for 2h at room temperature
...
In the present study, we demonstrate that the ethanol extract of H. erinaceus promotes the synthesis of NGF in 1321N1 human astrocytoma cells.
...
100 mg/ml of the H. erinaceus ethanol extract significantly increased NGF mRNA expression but not NGF protein synthesis.
...
In addition, the concentrations of hericenones in the ethanol extract were very low (the concentrations of hericenones C, D, and E in the 100 mg/ml ethanolextract of H. erinaceus were 20, 4, and 2ng/ml, respectively) compared to their effective concentration (33 mg/ml) as shown in a previous report [Kawagishi 1991]
These results, therefore, raise the possibility that H. erinaceus has unknown active compounds that promote NGF expression, other than hericenones, which are lipid-soluble (soluble in ethanol and/or ethyl acetate).
...
On the other hand, the mycelia of H. erinaceus are known to contain erinacines, which also stimulate NGF synthesis...However, it has not yet been reported that the fruit body of H. erinaceus contains erinacines. Thus, it is necessary to reevaluate whether fruit bodies contain erinacines, and to examine the existence of unknown derivatives with NGF-inducing activity in the fruit bodies of H. erinaceus.
Edited by chrono, 18 February 2010 - 10:43 PM.