Chemical profile of Roselle extract and its inhibitory activities on three digestive enzymes in vitro and in vivo.

Roselle is rich in an extensive diversity of beneficial substances, including phenolic acids, amino acids, anthocyanins, vitamins, and flavonoids. Herein, the chemical constituents in Roselle extract (RE) were identified by UPLC-DAD-QTOF-MS. Besides, its inhibitory effects on three digestive enzymes, i.e. α-amylase, α-glucosidase, and pancreatic lipase, were investigated in both in vitro and in vivo. Thirty-three constituents including hibiscus acid, 18 phenolic acids, 2 anthocyanins and 12 flavonoids were identified. The anthocyanins content in RE was 21.44 ± 0.68 %, while the contents of chlorogenic acids, rutin and quercetin were 17.76 ± 2.28 %, 0.31 ± 0.01 % and 0.32 ± 0.01 %, respectively. RE inhibited pancreatic lipase in a non-competitive way with an IC50 value of 0.84 mg/mL. Besides, it demonstrated a mixed-type inhibition on both α-glucosidase and α-amylase with IC50 values of 0.59 mg/mL and 1.93 mg/mL, respectively. Fluorescence quenching assays confirmed the binding of RE to the enzyme proteins. Furthermore, rats pre-treated with RE at doses of 50 and 100 mg/kg body weight (bwt) exhibited significant reductions in fat absorption and improvements in fat excretion through feces. Additionally, the in vivo study revealed that RE was effective in suppressing the increase of blood glucose after starch consumption, while its effects on maltose and sucrose consumption were relatively weak.

Effect of Suanzaoren Tang on Learning， Memory and Expression of Proteins Related to Hippocampal Synaptic Plasticity in PCPA-induced Insomnia Rat Model / 中国实验方剂学杂志

ObjectiveTo observe the effects of Suanzaoren Tang on the behavior， growth-associated protein-43 （GAP-43）， postsynaptic density protein-95 （PSD-95）， and synaptophysin Ⅰ （SynⅠ） of insomniac rats induced by p-chlorophenylalanine （PCPA）， and to investigate the mechanism of Suanzaoren Tang in improving the behavior of the insomniac rats. MethodSeventy-two SD rats were randomly assigned into 6 groups （12 rats in each group）： control group （normal saline）， PCPA （0.35 g·kg-1·d-1） group， estazolam （2.7×10-4 g·kg-1·d-1） group， and low-， medium-， and high-dose （3.25， 7.5， 15 g·kg-1·d-1， respectively） Suanzaoren Tang groups. The rat model of insomnia was established by intraperitoneal injection of PCPA and then the rats were administrated with corresponding drugs for 7 continuous days. The Morris water maze and Y-maze were used to test the learning and memory functions， and the open field to test anxiety. Histopathological changes in the hippocampus were observed via hematoxylin-eosin （HE） staining. The mRNA and protein levels of GAP-43， PSD-95， and SynⅠ in hippocampus were determined by real-time fluorescence quantitative polymerase chain reaction (Real-time PCR)， Western blot， and immunohistochemistry （IHC）. ResultCompared with the control group， the PCPA group showcased long escape latency， shortened time in the quadrants， and decreased times of crossing the platform in Morris water maze， decreased alternation correct rate was significantly Y-maze， and increased distance， mean velocity， and time in center of the open field test （P<0.01）. Furthermore， the PCPA-treated rats showed obvious pathological damage in the hippocampus and down-regulated mRNA and protein levels of GAP-43， PSD-95， and SynⅠ in hippocampus （P<0.01）. Compared with the PCPA group， the treatments with estazolam and different doses of Suanzaoren Tang improved the rat performance in Morris water maze， Y-maze， and open field test （P<0.05， P<0.01）， alleviated the hippocampal damage， and up-regulated the mRNA and protein levels of GAP-43， PSD-95， and SynⅠ （P<0.05， P<0.01）. ConclusionSuanzaoren Tang may alleviate the learning and memory disorders and anxiety in PCPA-induced insomnia rat model by up-regulating the mRNA and protein levels of hippocampal synaptic plasticity-associated proteins GAP-43， PSD-95， and SynⅠ.