Neuroprotective activity of two active chemical constituents from Tinospora hainanensis

OBJECTIVE@#To determine the chemical structure of the new compound and investigate the protective effects of Tinosporaic acid A and B towards in-vitro neuro.@*METHODS@#The structures of two new compounds were established by analyzing its 1D and 2D NMR spectra as well as HRESIMS. Their neuroprotective effects with respect to the antioxidant properties were evaluated by radical scavenging tests and hydrogen peroxide-injured oxidative stress model in PC12 cell lines. Cell morphology of treated PC12 cells was observed by phase contrast microscopy. In-vitro MTT assay, lactate dehydrogenase activity assay and oxidative stress markers (intracellular ROS production, MDA level, and caspase-3 activity) were used to evaluate the protective effects against hydrogen peroxide induced cytotoxicity in PC12 cells.@*RESULTS@#The two new compounds, named Tinosporaic acid A and B, were isolated and identified from the stem bark of Tinospora hainanensis. Cell viability studies identified a representative concentration for each extract that was subsequently used to measure oxidative stress markers. Both extracts were able to reverse the oxidative damage caused by hydrogen peroxide, thus promoting PC12 cells survival. The concentration of Tinosporaic acid A and B were 86.34 μg/mL and 22.06 μg/mL respectively, which is neuroprotective for EC50. The results indicated that both of them significantly attenuated hydrogen peroxide-induced neurotoxicity.@*CONCLUSION@#The two new compounds isolated from ethanol extracts of Tinospora hainanensis are the promising natural ones with neuroprotective activity and needed for further research.

Neuroprotective activity of two active chemical constituents from Tinospora hainanensis

Objective To determine the chemical structure of the new compound and investigate the protective effects of Tinosporaic acid A and B towards in-vitro neuro. Methods The structures of two new compounds were established by analyzing its 1D and 2D NMR spectra as well as HRESIMS. Their neuroprotective effects with respect to the antioxidant properties were evaluated by radical scavenging tests and hydrogen peroxide-injured oxidative stress model in PC12 cell lines. Cell morphology of treated PC12 cells was observed by phase contrast microscopy. In-vitro MTT assay, lactate dehydrogenase activity assay and oxidative stress markers (intracellular ROS production, MDA level, and caspase-3 activity) were used to evaluate the protective effects against hydrogen peroxide induced cytotoxicity in PC12 cells. Results The two new compounds, named Tinosporaic acid A and B, were isolated and identified from the stem bark of Tinospora hainanensis. Cell viability studies identified a representative concentration for each extract that was subsequently used to measure oxidative stress markers. Both extracts were able to reverse the oxidative damage caused by hydrogen peroxide, thus promoting PC12 cells survival. The concentration of Tinosporaic acid A and B were 86.34 μg/mL and 22.06 μg/mL respectively, which is neuroprotective for EC50. The results indicated that both of them significantly attenuated hydrogen peroxide-induced neurotoxicity. Conclusion The two new compounds isolated from ethanol extracts of Tinospora hainanensis are the promising natural ones with neuroprotective activity and needed for further research.

The protective effect and underlying mechanism of Hainan papaya water extract against neuronal apoptosis induced by Aβ40

OBJECTIVE@#To investigate whether Hainan papayas has protective effects in an Aβ40-induced primary neuron injury model and elucidate the underlying molecular mechanism.@*METHODS@#Cultured primary neurons from the dorsal root ganglia (DRG) of Sprague-Dawley (SD) rats were treated with 20 μM Aβ40 peptide, 100 μg/L Hainan papaya water extract, peptide plus extract, or culture medium for 24 h. Cell viability was measured by MTT assay, and neuronal apoptosis was evaluated by DAPI staining. ERK signaling pathway-associated molecule activation and changes in Bax expression were analyzed by Western blotting and immunofluorescence.@*RESULTS@#A cell viability rate of (44.11 ± 6.59)% in the Aβ40 group was rescued to (79.13 ± 6.64)% by adding different concentrations of the extract. DAPI showed pyknotic nuclei in 39.5% of Aβ40-treated cells; the fraction dropped to 17.4% in the 100 μg/L extract group. ERK phosphorylation was observed in the Aβ40 group but was ameliorated by pretreatment with 100 μg/L extract. Hainan papaya water extract also prevented Aβ40-induced phosphorylation of MEK, RSK1 and CREB associated with ERK signaling and downregulated Bax expression in the neurons.@*CONCLUSION@#The results suggest that Hainan papaya water extract has protective effects on neurons; the mechanism may be related to suppression of ERK signaling activation.

The protective effect and underlying mechanism of Hainan papaya water extract against neuronal apoptosis induced by Aβ40

Objective To investigate whether Hainan papayas has protective effects in an Aβ40-induced primary neuron injury model and elucidate the underlying molecular mechanism. Methods Cultured primary neurons from the dorsal root ganglia (DRG) of Sprague–Dawley (SD) rats were treated with 20 μM Aβ40 peptide, 100 μg/L Hainan papaya water extract, peptide plus extract, or culture medium for 24 h. Cell viability was measured by MTT assay, and neuronal apoptosis was evaluated by DAPI staining. ERK signaling pathway-associated molecule activation and changes in Bax expression were analyzed by Western blotting and immunofluorescence. Results A cell viability rate of (44.11 ± 6.59)% in the Aβ40 group was rescued to (79.13 ± 6.64)% by adding different concentrations of the extract. DAPI showed pyknotic nuclei in 39.5% of Aβ40-treated cells; the fraction dropped to 17.4% in the 100 μg/L extract group. ERK phosphorylation was observed in the Aβ40 group but was ameliorated by pretreatment with 100 μg/L extract. Hainan papaya water extract also prevented Aβ40-induced phosphorylation of MEK, RSK1 and CREB associated with ERK signaling and downregulated Bax expression in the neurons. Conclusion The results suggest that Hainan papaya water extract has protective effects on neurons; the mechanism may be related to suppression of ERK signaling activation.

srGAP3 promotes neurite outgrowth of dorsal root ganglion neurons by inactivating RAC1

OBJECTIVE@#To explore effect of srGAP3 promotes neurite outgrowth of dorsal root ganglion neurons.@*METHODS@#In this study, expression of Slit1 was observed predominantly in the glia, while expression of Robo2 and srGAP3 was detected in sensory neurons of postnatal rat cultured dorsal root ganglion (DRG). Furthermore, upregulation of srGAP3 following sciatic nerve transection was detected by immunohistochemistry and Western blotting.@*RESULTS@#It was observed that inhibition of neurite outgrowth in cultured adult DRG neurons following treatment with anti-srGAP3 or anti-Robo2 was more effectively (1.5-fold higher) than that following treatment with an anti-BDNF positive control antibody. It demonstrated that srGAP3 interacted with Robo2 and Slit1 protein to decrease Rac1-GTP activity in cultured adult rat DRG neurons and the opposite effect on Rac1-GTP activity was detected by co-immunoprecipitation and immunoblotting analyses following treatment with anti-Robo2 or anti-srGAP3. These data demonstrated a role for srGAP3 in neurite outgrowth of DRG sensory neurons.@*CONCLUSIONS@#Our observations suggest that srGAP3 promotes neurite outgrowth and filopodial growth cones by interacting with Robo2 to inactivate Rac1 in mammalian DRG neurons.

Effects of transforming growth factor-beta 1 on the peripheral nerve regeneration of rats / 中南大学学报(医学版)

OBJECTIVE@#To explore the effects of exogenous transforming growth factor-beta 1 (TGFbeta1) on peripheral nerve regeneration after the peripheral nerve injury and if TGFbeta1 regulates the expression of basic fibroblast growth factor (bFGF) in the anterior horn motoneurons of spinal cord during regeneration.@*METHODS@#Forty-eight rats were crushed on the right sciatic nerve and then randomly divided into 2 groups: TGFbeta1 group and NS group. In TGFbeta1 group, TGFbeta1 50 microL (0.1 microg/mL) was injected into the proximal nerve near to the crushed nerve and after the operation the injured leg was injected with equal TGFbeta1 whereas the NS was replaced in the NS group. The rats of each group survived for 3, 7, 14 and 21 days after the lesion. The bFGF expression in the anterior horn motoneurons of spinal cord was detected by immunohistochemistry (IHC). Semi-thin section and Fast Blue retrograde tracing were also performed with the rats surviving for 21 days to observe the regeneration of distal end in the injured right sciatic nerve.@*RESULTS@#The number of bFGF immunoreactive positive motoneurons in TGFbeta1 group was obviously higher than that of the NS group (P < 0.05). In the distal sciatic nerve of the rats treated with TGFbeta1, the number and diameter of regenerating myelinated axons and the thickness of myelinated sheath were more than those of the NS group (P < 0.05). The number of motoneurons in spinal cord and neurons in dorsol root ganglia (DRG) labelled with Fast Blue in the NS group was obviously lower than in the TGFbeta1 group (P < 0.01).@*CONCLUSION@#Exogenous TGFbeta1 plays an important role in promoting the peripheral nerve regeneration; TGFbeta1 up-regulates the bFGF expression in the anterior horn motoneurons of spinal cord during the peripheral nerve regeneration.