Plasma CRH Level Difference Between Wistar Rats Exposed To Acute Stress Due To Predator And To The Psychological Stress Device

Objective: Stress triggers and causes psychiatric disorders. This study compared stress generated by different stressors: a cat as the predator of rats and a Psychological Stress Device (PSD) which was developed and modified by the researchers based on the model by Xu and Rocher. Methods: Twenty-eight Wistar rats were simple randomly divided into one control group and six treatment groups, each consisting of 4 rats. Each treatment group was individually exposed to stressor for 30, 60, and 90 minutes. The first three treatment groups were treated using the PSD while the other three treatment groups were treated exposed to the cat. Plasma CRH level was measured using the ELISA (Cusabio) method. Result: Plasma CRH levels in the rat exposed to stressor using the PSD ranged from 9.89 to 50.22 ng/mL, higher than plasma CRH level in the groups exposed to cat ranged from 0.22 to 23.44 ng/mL with significance level (p0.05). Conclusion: Plasma CRH level of the rats exposed to stressor using the PSD was higher and positively correlate with the length of exposure compared to those exposed to cat.

Anti-diabetic potential of Urena lobata leaf extract through inhibition of dipeptidyl peptidase IV activity

Objective: To evaluate the anti-diabetic potential of leaf extract from Urena lobata (U. lobata) through dipeptidyl peptidase IV (DPP-IV) inhibitory activity. Methods: U. lobata leaf was extracted in hot water and ethanol. The activity of DPP-IV inhibitor was tested by in vitro study using gly-pro-p-nitroanilide as substrat of DPP-IV and vildagliptin, as standard reference. A product of the reactions between gly-pro-pnitroanilide and DPP-IV, was observed by microplate readers with λ = 405 nm. All data were expressed as mean ± SD and the IC50 value was determined by non linear regression curve fit. Active substances in leaf extract of U. lobata was analyzed by liquid chromatography-mass spectrometry. DPP-IV inhibitory activity of active compounds was evaluated in silico using docking server. Results: The ethanolic extract of U. lobata showed stronger DPP-IV inhibitor activity than water extract with the IC50 values of 1 654.64 and 6 489.88 mg/mL, respectively. Vildagliptin, based on standard reference for DPP-IV inhibitor activity, has IC50 value of 57.44 μg/mL. Based on in silico analysis, mangiferin, stigmasterol and β-sitosterol in U. lobata extract have a strong inhibitory activity on DPP-IV. Conclusions: The results showed that DPP-IV inhibitory activity of U. lobata is related to its active compounds such as mangiferin, stigmasterol and β-sitosterol.

Decreasing α-synuclein aggregation by methanolic extract of Centella asiatica in zebrafish Parkinson's model

Objective: To observe the effects of Centella asiatica ( C. asiatica) methanolic extract on α-synuclein aggregation and its expression in rotenone-exposed zebrafish. Methods: Zebrafish ( Danio rerio) were exposed to 5 μg/L rotenone for 28 days and co-incubated with 2.5, 5.0 and 10.0 μg/mL of C. asiatica methanolic extract. The medium was changed every 48 h for maintain the concentration of rotenone and extract. After 28 days zebrafish were sacrificed on the ice block and protein was isolated from zebrafish brain for ELISA of dopamine and Western blotting of α-synuclein. Immunohistochemistry was conducted to observe the α-synuclein expressions from histopathological preparation of zebrafish brain. The head were soaked in 10% formaline for less than 24 h and embedded onto paraffin block, then sliced for immunohistochemistry using anti α-synuclein antibody. We also measured zebrafish motility for 5 min in each week. Results: C. asiatica has important bioactive compounds such as asiaticoside that has anti-inflammatory and antioxidant properties. It may inhibit cascade reaction due to oxidative stress induced by rotenone. Decreasing reactive oxygen species proposed probability of radical attack to α-synuclein protein that caused aggregation and increase of its expression. The motility of zebrafish was also maintained in C. asiatica groups due to the increasing dopamine level in rotenone-induced zebrafish. High level of reactive oxygen species inactivated enzyme for dopamine synthesis such as tyrosine hydroxylase, and oxidized dopamine itself. Oxidized dopamine increased α-synuclein aggregation. Thus, the dopamine level decreased in rotenone-induced zebrafish, but C. asiatica increased dopamine level. Conclusions: C. asiatica has a potential to be developed as an anti-Parkinson's disease treatment due to its capability for minimized the sign of Parkinson's such as α-synuclein aggregation and expression, increasing motility and dopamine as well.