Adaptogenic Effects of Dihydroquercetin–Chitosan Composition during Modeling of Acute Hypoxia

New Perspectives of Taxifolin in Neurodegenerative Diseases

Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), cerebral amyloid angiopathy (CAA), and Huntington's disease (HD) are characterized by cognitive and motor dysfunctions and neurodegeneration. These diseases have become more severe over time and cannot be cured currently. Until now, most treatments for these diseases are only used to relieve the symptoms. Taxifolin (TAX), 3,5,7,3,4-pentahydroxy flavanone, also named dihydroquercetin, is a compound derived primarily from Douglas fir and Larix gemelini. TAX has been confirmed to exhibit various pharmacological activities, including anti-inflammation, anti-cancer, anti-virus, and regulation of oxidative stress effects. In the central nervous system, TAX has been demonstrated to inhibit Aβ fibril formation, protect neurons and improve cerebral blood flow, cognitive ability, and dyskinesia. At present, TAX is only applied as a health additive in clinical practice. This review aimed to summarize the application of TAX in neurodegenerative diseases and the underlying neuroprotective mechanisms, such as suppressing inflammation, attenuating oxidative stress, preventing Aβ protein formation, maintaining dopamine levels, and thus reducing neuronal loss.

Heteropterys tomentosa A. Juss: Toxicological and adaptogenic effects in experimental models

BACKGROUND

The constant pursuit of improved athletic performance characterizes high-performance sport and the use of medicinal plants as dietary supplements is becoming widespread among athletes to enhance long-term endurance performance.

AIM

The present study evaluated the toxicity of Heteropterys tomentosa (HEHt) and its acute adaptogenic effects.

METHODS

The in vitro safety profile was evaluated on CHO-k1 cells using the alamar Blue assay, at concentrations ranging from 3.125 to 200 µg/mL. In vivo acute oral toxicity was conducted in male and female mice with oral administration of graded doses of HEHt from 400 to 2000 mg/kg. A subchronic oral toxicity study was completed by oral administration of HEHt (50, 200 or 1000 mg/kg) and vehicle for 30 days in male Wistar rats. Clinical observations and toxicological related parameters were determined. Blood was collected for biochemical and hematological analyses, while histological examinations were performed on selected organs. Thereafter, an adaptogenic test consisting of progressive loads until exhaustion was conducted in rats ( n = 5/group) orally pre-treated with the vehicle and HEHt (25, 100 or 400 mg/kg).

RESULTS

HEHt exhibited no cytotoxic effects on the CHO-k1 cells and, apparently, no acute toxicity in mice and no subchronic toxicity in rats. An ergogenic effect was observed only at the dose of 25 mg/kg compared with the vehicle in relation to time to exhaustion and exercise load ( p = .011 and .019, respectively). HEHt is safe at up to 400 mg/kg, contains astilbin and taxifolin as the major phytochemical compounds, and exhibited a potential adaptogenic effect.

CONCLUSIONS

These results justify its anecdotal usage as a tonic, show that the hydroethanolic maceration of the root does not cause toxicity, and provide scientific evidence of its potential as a source of new adaptogenic substance(s).

Protective effect of polyphenols in an inflammatory process associated with experimental pulmonary fibrosis in mice

Polyphenols have been described to have a wide range of biological activities, and many reports, published during recent years, have highlighted the beneficial effects of phenolic compounds, illustrating their promising role as therapeutic tools in several acute and chronic disorders. The purpose of study was to evaluate, in an already-assessed model of lung injury caused by bleomycin (BLM) administration, the role of resveratrol and quercetin, as well as to explore the potential beneficial properties of a mango leaf extract, rich in mangiferin, and a grape leaf extract, rich in dihydroquercetin (DHQ), on the same model. Mice were subjected to intra-tracheal administration of BLM, and polyphenols were administered by oral route immediately after BLM instillation and daily for 7 d. Treatment with resveratrol, mangiferin, quercetin and DHQ inhibited oedema formation and body weight loss, as well as ameliorated polymorphonuclear infiltration into the lung tissue and reduced the number of inflammatory cells in bronchoalveolar lavage fluid. Moreover, polyphenols suppressed inducible nitric oxide synthase expression, and prevented oxidative and nitroxidative lung injury, as shown by the reduced nitrotyrosine and poly (ADP-ribose) polymerase levels. The degree of apoptosis, as evaluated by Bid and Bcl-2 balance, was also suppressed after polyphenol treatment. Finally, these natural products down-regulated cyclo-oxygenase-2, extracellular signal-regulated kinase phosphorylated expression and reduced NF-κBp65 translocation. Our findings confirmed the anti-inflammatory effects of resveratrol and quercetin in BLM-induced lung damage, and highlight, for the first time, the protective properties of exogenous administration of mangiferin and DHQ on experimental pulmonary fibrosis.