Alpinia oxyphylla Miq. fruit extract activates IGFR-PI3K/Akt signaling to induce Schwann cell proliferation and sciatic nerve regeneration.

BACKGROUND: It is known that the medicinal herb Alpinia oxyphylla Miq. is widely used as a remedy for diarrhea as well as the symptoms accompanying hypertension and cerebrovascular disorders. Moreover, it has also been reported that Alpinia oxyphylla Miq. has beneficial effects on anti-senescence and neuro-protection. This study focuses on the molecular mechanisms by which the Alpinia oxyphylla Miq. fruits promote neuron regeneration. METHODS: A piece of silicone rubber was guided across a 15 mm gap in the sciatic nerve of a rat. This nerve gap was then filled with various doses of Alpinia oxyphylla Miq. fruits to assess their regenerative effect on damaged nerves. Further, we investigated the role of Alpinia oxyphylla Miq. fruits in RSC96 Schwann cell proliferation. RESULTS: Our current results showed that treatment with the extract of Alpinia oxyphylla Miq. fruits triggers the phosphorylated insulin-like growth factor-1 receptor- phosphatidylinositol 3-kinase/serine-threonine kinase pathway, and up-regulated the proliferating cell nuclear antigen in a dose-dependent manner. Cell cycle analysis on RSC96 Schwann cells showed that, after exposure to Alpinia oxyphylla Miq. fruit extract, the transition from the first gap phase to the synthesis phase occurs in 12-18 h. The expression of the cell cycle regulatory proteins cyclin D1, cyclin E and cyclin A increased in a dose-dependent manner. Transfection with a small interfering RNA blocked the expression of phosphatidylinositol 3-kinase and induced down-regulation both on the mRNA and protein levels, which resulted in a reduction of the expression of the survival factor B-cell lymphoma 2. CONCLUSION: We provide positive results that demonstrate that Alpinia oxyphylla Miq. fruits facilitate the survival and proliferation of RSC96 cells via insulin-like growth factor-1 signaling.

Effect of water extracts of Alpinia oxyphylla Miq. fruit on memory impairment in cerebral ischemia rats / 中华行为医学与脑科学杂志

Objective This report investigate the intervention effect of the water extract of Alpinia oxyphylla Miq. fruit (AOF)on memory impairment and the mechanism in cerebral ischemia rats. Methods 48 Rats were randomly divided into sham-operated group(n=12), ischemia group(n=12), AOF group Ⅰ( n= 12)and AOF group Ⅱ (n= 12). The model of transient cerebral ischemic/reperfusion was made by bilateral occlusion of common carotid arteries in rats and combination with reducing blood pressure with an abdominal injection of so-dium nitroprusside. Learning-memory ability was observed by step through test. The content of NO and the activi-ties of NOS were measured in hippocampus. Results In step through test,the latency in ischemia group[(143.8±65.2)s]significantly decreased, the number of errors (8.9±4.2 ) significantly increased compared with sham-operated group [latency: (257.2±67.1 ) s; number of errors: (1.7±1.1 ), P<0.01 ]. The latency in AOF group Ⅰ and AOF group Ⅱ[(186.5±46.2) s, (193.4±43.7 ) s ] significantly increased, the number of errors (6.1±2.9,5.2±2.1 ) significantly decreased compared with ischemia group(P<0.05, P<0.01). In hippocampus, the content of NO and the activities of NOS in ischemia group [(56.53±27.42) nmol/mg prot, (17.23±5.64) nmol/mg prot] significantly increased compared with sham-operated group[ (40.02±17.9 ) nmol/mg prot, ( 10.46±6.15)nmol/mg prot], and in AOF group Ⅰ and AOF group Ⅱ [content of NO:group Ⅰ (46.60 ±20. 26)nmol/mg prot,group Ⅱ (42.38±21.23) nmol/mg prot ;activities of NOS:group Ⅰ (13.98±5.13 ) nmol/mg pint,group Ⅱ(13.61±5.27) nmol/mg prot] significantly decreased compared with ischemia group(P<0.05). Conclu-sion AOF could significantly ameliorate the memory impairment in cerebral ischemic rats. Its effects may be in-volved in the decrease of content of NO and activities of NOS in hippocampus.