Lingling Shi

Tyrosol Prevents Ischemia/Reperfusion-Induced Cardiac Injury in H9c2 Cells: Involvement of ROS, Hsp70, JNK and ERK, and Apoptosis

Ischemia-Reperfusion (I/R) injury causes ROS overproduction, creating oxidative stress, and can trigger myocyte death, resulting in heart failure. Tyrosol is an antioxidant abounded in diets and medicine. Our objective was to investigate the protective effect of tyrosol on I/R-caused mortality in H9c2 cardiomyocytes through its influence on ROS, Hsp70, ERK, JNK, Bcl-2, Bax and caspase-8. A simulated I/R model was used, myocytes loss was examined by MTT, and ROS levels were measured using DCFH-DA. Nuclear condensation and caspase-3 activity were assessed by DAPI staining and fluorometric assay. Phosphorylated ERK and JNK were determined by electrochemiluminescent ELISA, and Hsp70, Bcl-2, Bax and caspase-8 were examined by Western blotting. Results show that tyrosol salvaged myocyte loss, inhibited nuclear condensation and caspase-3 activity dose-dependently, indicating its protection against I/R-caused myocyte loss. Furthermore, tyrosol significantly inhibited ROS accumulation and activation of ERK and JNK, augmenting Hsp70 expression. Besides, tyrosol inhibited I/R-induced apoptosis, associated with retained anti-apoptotic Bcl-2 protein, and attenuated pro-apoptotic Bax protein, resulting in a preservation of Bcl-2/Bax ratio. Finally, tyrosol notably decreased cleaved caspase-8 levels. In conclusion, cytoprotection of tyrosol in I/R-caused myocyte mortality was involved with the mitigation of ROS, prohibition of the activation of ERK, JNK and caspase-8, and elevation of Hsp70 and Bcl-2/Bax ratio.

Hypoglycemic and hypolipidemic effects of polyphenols from burs of Castanea mollissima Blume.

Substantial evidence suggests that phenolic extracts of Castanea mollissima spiny burs (CMPE) increase pancreatic cell viability after STZ (streptozotocin) treatment as a result of their antioxidant properties. In the present study, the hypoglycemic and hypolipidemic activities of CMPE were studied in normal and STZ-induced diabetic rats CMPE were orally administrated at doses of 150 and 300 mg/kg twice a day for 12 consecutive days. Serum glucose, triglyceride, total cholesterol, HDL- and LDL-cholesterol levels, malondialdehyde (MDA) level and SOD activity in liver, kidney, spleen and heart tissues were measured spectrophotometrically. In normal rats, no significant changes were observed in serum glucose, lipid profiles and tissue MDA and GSH levels after orally administration of CMPE. In diabetic rats, oral administration of CMPE at a dose of 300 mg/kg caused significant decreases in serum glucose, triglyceride, total cholesterol, LDL-cholesterol levels, as well as MDA and GSH levels in spleen and liver tissues. However, the 300 mg/kg dosage caused a significant body weight loss in both normal and diabetic rats. The observed effects indicated that CMPE could be further developed as a drug to prevent abnormal changes in blood glucose and lipid profile and to attenuate lipid peroxidation in liver and spleen tissues.

α-Glucosidase Inhibitory Activity of Polyphenols from the Burs of Castanea mollissima Blume

Polyphenol extracts from the burs of Castanea mollissima Blume (CMPE) exhibited potential antioxidant and hypoglycemic activities. The α-glucosidase inhibitory activities of CMPE were assessed as a means of elucidating the mechanism behind its hypoglycemic activities. In vitro studies showed that CMPE significantly inhibited both yeast α-glucosidase, through a noncompetitive mode with an IC50 of 0.33 μg/mL, and rat intestinal α-glucosidase. In vivo studies revealed that oral administration of CMPE at doses of 600 mg/kg significantly reduced postprandial blood glucose levels by 27.2% in normal rats following sucrose challenges. Gel permeation chromatography revealed that CMPE exhibited typical characteristics of high-molecular-mass polymers with mean (Mn) and weight (Mw) average molecular weights of 35.4 and 50.7 kDa, respectively, and a polydispersity (Mw/Mn) of 1.432. Acid hydrolysis analysis indicated the presence of ellagitannins. These data suggest that CMPE, enriched with ellagitannins, would be an efficacious dietary supplement for diabetes management through the inhibition of alpha-glucosidase.

Characterization of fatty acid composition from five perilla seed oils in China and its relationship to annual growth temperature

Omega-3 fatty acids have been shown to reduce inflammation and may help prevent chronic diseases like heart disease and arthritis. Alpha-linolenic acid is a type of ω-3 fatty acids and has been reported with a remarkably high content (>50%) only in seeds of several plant species, for example, Perilla and Linum usitatissimum L. It is a valuable compound obtained from plants which can provide health benefits similar to those derived from fish oil. In this study, five seed samples from five varieties of the monotypic genus Perilla collected from five provinces in China were analyzed to determine their fatty acid composition. The seed oils were extracted using Soxhlet, and oil contents of these samples ranged from 33.25 to 42.58% (wt/wt). Fatty acid compositions were then analyzed using gas chromatographymass spectrometry (GC-MS). Saturated, monounsaturated and polyunsaturated fatty acids accounted for 9.16 to 10.49, 13.78 to 20.93 and 63.12 to 73.45% of their totals, respectively, in which the content of the unsaturated fatty acids was over 90% on average. Moreover, α-linolenic acid was dominant (52.58 to 61.98%) in all the oil samples, and it comprised 65.67 to 68.37% of the total unsaturated fatty acids and 83.30 to 84.38% of the polyunsaturated acids, respectively. However, contents of the ω-6 linoleic acid in the five samples were only 10.54 to 15.87%, and the ratio of ω-6 to ω-3 fatty acids was as low as 0.2 to 0.26. The results indicate that Perilla oil is presently the best quality oil derived from plant sources and hence it could be developed into commercial products to serve as a valuable alternative vegetable oil. Furthermore, oil from seeds obtained in regions with lower average growth temperature has relatively higher percentage of unsaturated fatty acids.

Urolithin C, a gut metabolite of ellagic acid, induces apoptosis in PC12 cells through a mitochondria-mediated pathway

Urolithins (Uros), metabolites of ellagitannins (ET) and ellagic acid (EA) produced by gut microbiota, showed better bioavailability and extensive bioactivity, and were considered as the active compounds responsible for the health benefits exerted by ET-containing foodstuffs. Here, we chemically synthesized three Uros including Uros A, B, and C and compared their anti-proliferative activities with that of EA in PC12 cells. MTT assay showed that EA significantly promoted, while Uros significantly inhibited the proliferation of PC12 cells, among which UroC showed the strongest anti-proliferation. UroC treatment actively increased the lactate dehydrogenase (LDH) release and lipid peroxidation malondialdehyde (MDA), stimulated reactive oxygen species (ROS) formation and mitochondrial membrane depolarization, and caused calcium dyshomeostasis. Furthermore, flow cytometry analysis showed that UroC treatment induced apoptosis and S phase cell cycle arrest with increasing UroC concentrations. Consequently, UroC also induced imbalance in the Bcl-2/Bax ratio, which triggered the caspase cascade, thereby shifting the balance in favor of apoptosis, as evidenced by western blotting and real-time PCR. These observations indicated that UroC possessed significantly different anti-proliferation activities from EA, and actively induced cell apoptosis through a mitochondria-mediated pathway.

Ziziphus mucronata: an underutilized traditional medicinal plant in Africa

In Africa, rural people depend heavily, if not exclusively, on medicinal plants and indigenous healthcare knowledge to meet their medical needs. Over 80000 flowering plant species are used medicinally worldwide. Amongst them are the underutilized Ziziphus species in the Rhamnaceae family. In terms of abundance and economic value, Z. jujuba and Z. mauritiana are currently the most important, especially in China and India where they are cultivated and exploited for medicinal use and their edible fruits. We examined a related common species widely distributed in Africa, Z. mucronata, whose economic value has not, as yet, been explored. Local people in various African countries use its different parts to cure a large number of diseases, many of which are similar to those treated with Z. jujuba and Z. mauritiana. Several studies have shown that Z. mucronata has cyclopeptide alkaloids, i.e., mucronines F, G and H, with antibacterial properties. Conservation strategies to sustain and maximize the benefits of Z. mucronata to people are proposed.

Phenolic profiles and antioxidant activities of six Chinese pomegranate (Punica granatum L.) cultivars

ABSTRACT The physicochemical characteristics, phenolic contents, and antioxidant capacities of the juices, seeds, and peels of six pomegranate cultivars from Shandong and Xinjiang provinces of China were compared. Results showed that high variability occurred in the physicochemical properties of the fruits, including fruit size, 100-aril weight, juice yield, titratable acidity (TA), total reducing sugar (TS), total soluble solids (TSS), and TS/TA. Comparison of the distribution of the phenolic contents and antioxidant activities in the peels, juices, and seeds revealed that the pomegranate peels possessed much more phenolic components and stronger antioxidant activities than the seeds and juices. The phenolic components of pomegranate peels were structurally identified and quantified by ultra-performance liquid chromatography coupled with mass spectrum (UPLC–DAD–ESI/MSn), and punicalagin (α- and β-isomers) was found as the predominant phenolic component. Correlation analysis revealed that the antioxidant activities were highly positively correlated with the total phenolics and flavonoids. The above results indicated that the pomegranate peel was the most valuable part because of abundant total phenolics and high antioxidant activities, and the best cultivar for fresh consumption, juice extraction, and bioactive components preparation was “SD-QP.”