Prophylactic effects of sporoderm-removed Ganoderma lucidum spores in a rat model of streptozotocin-induced sporadic Alzheimer's disease.

ETHNOPHARMACOLOGICAL RELEVANCE: Ganoderma lucidum (G. lucidum, Lingzhi), also known as "immortality mushroom" has been broadly used to improve health and longevity for thousands of years in Asia. G. lucidum and its spores have been used to promote health, based on its broad pharmacological and therapeutic activity. This species is recorded in Chinese traditional formula as a nootropic and has been suggested to improve cognitive dysfunction in Alzheimer's disease. However, little is known about the nootropic effects and molecular mechanism of action of G. lucidum spores. AIM OF THE STUDY: The present study investigated the protective effects of sporoderm-deficient Ganoderma lucidum spores (RGLS) against learning and memory impairments and its mechanism of action. MATERIALS AND METHODS: In the Morris water maze, the effects of RGLS on learning and memory impairments were evaluated in a rat model of sporadic Alzheimer's disease that was induced by an intracerebroventricular injection of streptozotocin (STZ). Changes in amyloid ß (Aß) expression, Tau expression and phosphorylation, brain-derived neurotrophic factor (BDNF), and the BDNF receptor tropomyosin-related kinase B (TrkB) in the hippocampus were evaluated by Western blot. RESULTS: Treatment with RGLS (360 and 720 mg/kg) significantly enhanced memory in the rat model of STZ-induced sporadic Alzheimer's disease and reversed the STZ-induced increases in Aß expression and Tau protein expression and phosphorylation at Ser199, Ser202, and Ser396. The STZ-induced decreases in neurotrophic factors, including BDNF, TrkB and TrkB phosphorylation at Tyr816, were reversed by treatment with RGLS. CONCLUSION: These findings indicate that RGLS prevented learning and memory impairments in the present rat model of STZ-induced sporadic Alzheimer's disease, and these effects depended on a decrease in Aß expression and Tau hyperphosphorylation and the modulation of BDNF-TrkB signaling in the hippocampus.

Oleanane triterpenoids from Akebiae Caulis exhibit inhibitory effects on Aß42 induced fibrillogenesis.

Previous phytochemical investigations of Akebiae Caulis resulted in the isolation of triterpenes, triterpene glycosides, phenylethanoid glycosides and megastigmane glycoside. Amyloid beta (Aß), the main component of the senile plaques detected in Alzheimer's disease, induces cell death. However, only a limited number of studies have addressed the biological and pharmacological effects of Akebiae Caulis. In particular, the inhibitory activity of Akebiae Caulis against Aß42 fibrillogenesis remains unclear. Herein, a new triterpene glycoside, akequintoside F (1), along with nine known compounds pulsatilla saponin A (2), collinsonidin (3), akebonic acid (4), hederagenin (5), 1-(3',4'-dihydroxycinnamoyl) cyclopentane-2,3-diol (6), asperosaponin C (7), leontoside A (8), quinatic acid (9), and quinatoside A (10) were isolated from Akebiae Caulis using repeated column chromatography with silica gel, LiChroprep RP-18, and MCI gel. The chemical structures of compounds 1-10 were illustrated based on 1D and 2D NMR spectroscopy, including 1H-1H COSY, HSQC, HMBC and NOESY spectroscopic analyses. Compound 1 a novel compound and known compounds 6 and 7 were isolated for the first time from this plant. Among these compounds, 1, 3, 4, 5 and 7 displayed significant inhibitory effects on Aß42 induced fibrillogenesis. We present the first report of new compound 1 and the inhibitory effects of components from Akebiae Caulis on Aß42 fibrillogenesis.