Effect of taxifolin on oxidative gastric injury induced by celiac artery ligation in rats

Effects of taxifolin on aspirin-induced gastric damage in rats: macroscopic and biochemical evaluation

Taxifolin (dihydroquercetin) is a flavanonol isolated from various plants and has antioxidant effects. The aim of our study was to macroscopically and biochemically investigate the effects of taxifolin on aspirin-induced oxidative gastric damage in rats and to evaluate them by comparison with those of famotidine. Rats were divided into four drug administration groups: a healthy control group, an aspirin-only group (ASG), a taxifolin + aspirin group (TASG), and a famotidine + aspirin group (FASG). The results revealed that in light of the results that we obtained, 50 mg/kg taxifolin had anti-ulcer effects. At this dose, taxifolin was able to bring COX-1 activities to a level close to those seen in healthy rats with appropriate macroscopic, oxidant/antioxidant, and biochemical parameters. Based on these results, it can be said that taxifolin may be successfully used as a more potent alternative to famotidine, which is the currently accepted treatment for aspirin-induced ulcers.

Hepatoprotective and neuroprotective effect of taxifolin on hepatic encephalopathy in rats

This study was planned to assess the potential protective effects of taxifolin against thioacetamide-induced hepatic encephalopathy and subsequently to portray its behavioural results. The experimental model was induced with three doses of (200 mg/kg i.p.) thioacetamide and taxifolin (50 and 100 mg/kg, p.o.) was administered for fourteen days. Taxifolin effectively attenuated hepatic encephalopathy through decrease in AST, ALT, ALP and LDH concentrations and improvement of hyperammonemia, and increase in antioxidant capacity by decreasing MDA, ROS, and increasing CAT and GSH. In addition, the expressions of NF-κB, TNF-α, IL-1β, caspase-3 and Bax was down-regulated while IL-10 and Bcl-2 expressions were up-regulated with taxifolin treatment. The recovery was confirmed by downregulation of iNOS and 8-OHdG expressions in our immunohistochemical analysis. Taxifolin treatment reduced the disrupting role of thioacetamide as seen by corrected hyperammonemia as well as preservation of astrocyte and hepatocyte structure. Elevated plus maze and locomotor activity tests also proved that taxifolin might repeal the neurobehavioral disabilities. In conclusion, taxifolin has shown hepatoprotective and neuroprotective roles with antioxidant and anti-inflammatory effects, as well as suppressing the excessive release of ammonia, and it eventually reversed neurobehavioral impairments.

Effectiveness of the fruit of Rosa odorata sweet var. gigantea (Coll. et Hemsl.) Rehd. et Wils in the protection and the healing of ethanol-induced rat gastric mucosa ulcer based on Nrf2/NF-κB pathway regulation

ETHNOPHARMACOLOGICAL RELEVANCE

Rosa odorata Sweet var. gigantea (Coll. et Hemsl.) Rehd. et Wils (Rosaceae), is also known as "GU-GONG-GUO", the root of which has been recognized as common ethnodrug from the Yi nationality for treating inflammatory bowel disease. The aim of the present study was to investigate the preventive and curative effects of extract from the fruits of Rosa odorata Sweet var. gigantea (Coll.et Hemsl.) Rehd. et Wils (FOE) in vitro and in vivo as well as elucidate the potential mechanisms of the action involved.

MATERIALS AND METHODS

Male Wistar rats were applied to ethanol-induced gastric ulcer model. They were divided into six groups: control, model (GU), positive (Magnesium aluminate chewable tablets, 125 mg/kg), FOE low (125 mg/kg), middle (250 mg/kg) and high (500 mg/kg) doses groups. Histopathology observation of gastric tissues was detected by hematoxylin and eosin (H&E) staining. The expression of Nrf2, HO-1, Keap1, NF-κB p65 and IKKα/β in gastric tissues were evaluated by immunohistochemistry (IHC). The levels of cytokines in serum and tissues were measured by Enzyme-linked immunosorbent assay (ELISA). The expression of Nrf2, HO-1, Keap1, NF-κB p65, IKKα/β, PCNA and COX2 proteins were ulteriorly assessed by Western blotting to elucidate the molecular mechanism of FOE's protective effect on gastric ulcer.

RESULTS

MTT detection showed that LPS reduced RAW264.7 cell survival, and FOE blocked the inhibition of RAW264.7 cell growth induced by LPS. When RAW264.7 cells were treated with both FOE (100 μg mL^-1) and LPS (5 μg mL^-1) for 24 h, compared with the model group, the level of NO, TNF-α, IL-6, IL-1β and MDA significantly decreased, and the activity of SOD was significantly reduced. Obvious pathological injuries in the GU model group were observed, which was improved after treatments with FOE. The contents of pro-inflammatory factors in serum and tissues were decreased by 25% whereas prostaglandin E2 (PGE2) and epidermal growth factor (EGF) were increased by 30% in a dose-dependent manner after FOE (500 mg/kg) treatments. In addition to the promotion effects of superoxide dismutase (SOD), FOE (500 mg/kg) also attenuated the levels of nitric oxide (NO) and malondialdehyde (MDA) by 20%. Likewise, the expression of NF-κB p65, IKKα/β and Keap1 were suppressed after treatments with FOE whereas Nrf2 and HO-1 showed the opposite trend, which mechanisms were found to be associated with Nrf2/NF-κB signaling pathways.

CONCLUSION

The study demonstrated that FOE is able to protect against GU via inhibiting NF-κB signaling pathway and activating Nrf2 signaling pathway, which might provide a stronger theoretical basis for the treatment of GU.

Taxifolin and gastro-adhesive microparticles containing taxifolin promotes gastric healing in vivo, inhibits Helicobacter pylori in vitro and proton pump reversibly in silico

Taxifolin (3,5,7,3,4-pentahydroxy flavanone or dihydroquercetin, Tax) was identified as a gastroprotective compound and a gastroadhesive formulation was recently developed to prolong its residence time and release in the stomach. So, the gastric healing effectiveness of Tax and gastro-mucoadhesive microparticles containing Tax (MPTax) against the acetic acid induced-gastric ulcer in rats was investigated in this study. Moreover, the interactions between Tax and H⁺/K⁺-ATPase were investigated in silico, and its anti- H. pylori activity was determined in vitro. The oral treatment with MPTax (81.37 mg/kg, containing 12.29% of Tax) twice a day for seven days reduced the ulcer area by 63%, compared to vehicle-treated group (Veh: 91.9 ± 10.3 mm²). Tax (10 mg/kg, p.o) reduced the ulcer by 40% but with a p = 0.07 versus Veh group. Histological analysis confirmed these effects. Tax and MPTax increased the gastric mucin amount, reduced the myeloperoxidase activity, and increased the glutathione reduced content at ulcer site. However, only MPTax decreased the lipoperoxide accumulation at ulcer site. Besides, Tax and MPTax normalize the catalase and glutathione S-transferase activity. Tax showed reversible interaction with H⁺/K⁺-ATPase in silico and its anti-H. pylori effects was confirmed (MIC = 625 μg/mL). These results suggest that the antiulcer property of Tax involves the strengthening of the gastric protective factors in parallel to its inhibitory interaction with H⁺/K⁺-ATPase and H. pylori. Considering that ulcer healing action displayed by Tax was favored by gastroadhesive microparticles, this approach seems to be promising for its oral delivery to treat acid-peptic diseases.

Ultrasound-Assisted Extraction of Taxifolin, Diosmin, and Quercetin from Abies nephrolepis (Trautv.) Maxim: Kinetic and Thermodynamic Characteristics

Extraction behaviors of the 3 flavonoids taxifolin, diosmin, and quercetin have been investigated in Abies nephrolepis leaves and bark. The following operation parameters—ethanol volume fraction, liquid–solid ratio, temperature, ultrasound irradiation power and time, and ultrasound frequency—were varied to study their effect on the yield of the 3 flavonoids during extraction. The results showed that a low extraction efficiency occurred at 293.15 K due to slow kinetics, while the situation was significantly improved at 333.15 K. The kinetic data for the extraction yields of the 3 flavonoids achieved good fits by the first-order kinetic model. From the thermodynamic analysis results, we realized that the ultrasound-assisted extraction of taxifolin, diosmin, and quercetin from the leaves and bark of A. nephrolepis was a spontaneous and endothermic process in which the disorder increased (ΔG⁰ < 0, ΔH⁰ > 0, and ΔS⁰ > 0). According to the response surface methodology (RSM) analysis, under the optimal operation conditions (ethanol concentration of 50%, liquid–solid ratio of 20 mL/g, frequency of 45 kHz, extraction time of 39.25 min, ultrasound irradiation power of 160 W and temperature of 332.19 K), the total yield of the 3 flavonoids were 100.93 ± 4.01 mg/g from the leaves of A. nephrolepis (with 31.03 ± 1.51 mg/g, 0.31 ± 0.01 mg/g, 69.59 ± 2.57 mg/g for taxifolin, diosmin, and quercetin, respectively), and under the optimal operation conditions (ethanol concentration of 50%, liquid–solid ratio of 20 mL/g, frequency of 45 kHz, extraction time of 36.80 min, ultrasound irradiation power of 150 W and temperature of 328.78 K), 16.05 mg/g ± 0.38 mg/g were obtained from the bark of A. nephrolepis (with 1.44 ± 0.05 mg/g, 0.47 ± 0.01 mg/g, 14.14 ± 0.38 mg/g for taxifolin, diosmin, and quercetin, respectively), which were close to the prediction values.