**3. NGF synthesis of** *H. ramosum* **mycelia**

Senile dementia, such as AD, is a severe problem, with no effective therapy [25]. Neurotrophic factors, including NGF, brain-derived neurotrophic factor (BDNF), neurotrophin 3, and glial-derived neurotrophic factor (GDNF), have been implicated in the prevention of neuronal death and promotion of neurite outgrowth [26]. Among them, NGF has been associated with AD [27], with decreased NGF levels in the basal forebrain of AD patients. Intracerebroventricular administration of NGF has been reported to eliminate degeneration and resultant cognitive deficits in rats after brain injury [28]. In rats, poor cognitive effects caused by neuronal degeneration have been shown to be eliminated by intracerebroventricular administration of NGF. However, since NGF cannot cross the blood-brain barrier, utilizing it for therapeutic application will be difficult. Several studies have investigated low-molecular-weight compounds, such as catecholamines [29], benzoquinones [30], hericenones [31], and erinacines [32], for their ability to promote NGF synthesis.

*H. erinaceum* is a common fungus found in the East Asian diet. Hericenones [33] have been isolated from the fruiting bodies of *H. erinaceum* and erinacines [34] have been identified in *H. erinaceum* mycelia. *H. erinaceum* may be valuable in the treatment and prevention of dementia [35, 36]. However, to our knowledge, no reports have shown the induction of NGF synthesis by *H. ramosum* mycelia. In this section, we show the results of our assessment on the ability of *H. erinaceum* and *H. ramosum* mycelia to induce NGF synthesis.
