Eliza Oprea

The antioxidant response induced by Lonicera caerulaea berry extracts in animals bearing experimental solid tumors.

Lonicera caerulea is a species of bush native to the Kamchatka Peninsula (Russian Far East) whose berries have been extensively studied due to their potential high antioxidant activity. The aim of our work was to investigate the in vivo effects of the antioxidant action of Lonicera caerulea berry extracts on the dynamics of experimentally-induced tumors. Our data showed that aqueous Lonicera caerulaea extracts reduced the tumor volume when administered continuously during the tumor growth and development stages, but augmented the tumor growth when the administration of extracts started three weeks before tumor grafting. Prolonged administration of Lonicera caerulaea berry extracts induced the antioxidant defense mechanism in the tumor tissues, while surprisingly amplifying the peripheral oxidative stress.

Natural compounds and the hypoxia-inducible factor (HIF) signalling pathway

A decline in the tissue oxygen level below normal leads to cellular hypoxia. This situation is very frequently encountered in solid tumors as existing blood vessels cannot satisfy the requirements in oxygen of the rapidly growing tumor. Like hyperoxia, hypoxia is a stress factor for cells and tissues. Adapting to this stressful situation leads to activation of the dimeric transcription factor hypoxia-inducible factor-1 (HIF-1) that induces gene expression in promoting tumor cell survival. In addition, hypoxia acts as a selection factor for radio- and chemotherapy resistant tumor cells with a high potential of malignancy. Consequently, over expression of the HIF-1alpha subunit is associated with an advanced disease stage and poor prognosis of cancer patients. During the last few years intense effort has been made in investigating natural compounds that can be used as HIF-1 inhibitors. These compounds aim to suppress tumor hypoxia and to increase the susceptibility of tumor cells to radio- and chemo-therapy. In this review we summarize recent findings concerning HIF-1 regulation and present a survey of HIF-1 inhibiting natural compounds that have been discovered in the last few years.

Dynamic of oxidative and nitrosative stress markers during the convalescent period of stroke patients undergoing rehabilitation

Background Stroke patients have a redox imbalance, a consequence of both the cerebrovascular event and the associated pathological conditions. Our study was aimed to investigate the dynamic of some oxidative and nitrosative markers during the convalescent phase of postacute stroke patients undergoing rehabilitation. Methods We assessed thiol, advanced oxidation protein product, protein carbonyl, 3-nitro-l-tyrosine, ceruloplasmin and oxidized LDL concentrations, as well as gamma-glutamyltranspeptidase (GGT) activity in 20 patients at the beginning of the hospitalization and at the discharge moment, respectively, and 24 apparently healthy controls. Results We found significantly increased values for GGT (P = 0.04), ceruloplasmin (P = 0.01) and protein carbonyl (P = 0.04) in stroke patients at the hospitalization moment when compared with healthy controls, while total thiols were significantly decreased (P = 0.002). Rehabilitation was associated with a significant decrease of protein carbonyl (P = 0.03) and oxidized LDL particle concentrations (P = 0.03), as well as GGT activity (P = 0.02). At the hospitalization moment, both GGT and ceruloplasmin were significantly negatively correlated with non-proteic thiols (r = −0.44, P = 0.049, and r = −0.53, P = 0.015, respectively) and significantly positively with protein carbonyls (r = +0.80, P < 0.001, and r = +0.69, P < 0.001, respectively) suggesting putative roles of GGT and ceruloplasmin in the redox imbalance. Conclusions These results highlight the existence of a redox imbalance in postacute stroke patients, and the possible benefits of an antioxidant-based therapy for the recovery of these patients.

Chemical Composition and Antipathogenic Activity of Artemisia annua Essential Oil from Romania.

The essential oil extracted by hydrodistillation from Romanian Artemisia annua aerial parts was characterized by GC/MS analysis, which allowed the identification of 94.64% of the total oil composition. The main components were camphor (17.74%), α‐pinene (9.66%), germacrene D (7.55%), 1,8‐cineole (7.24%), trans‐β‐caryophyllene (7.02%), and artemisia ketone (6.26%). The antimicrobial activity of this essential oil was evaluated by determining the following parameters: minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), minimal fungicidal concentration (MFC), and minimal biofilm eradication concentration (MBEC). Moreover, the soluble virulence factors were quantified with different biochemical substrates incorporated in the culture media. The reference and resistant, clinical strains proved to be susceptible to the A. annua oil, with MICs ranging from 0.51 to 16.33 mg/ml. The tested essential oil also showed good antibiofilm activity, inhibiting both the initial stage of the microbial cell adhesion to the inert substratum and the preformed mature biofilm. When used at subinhibitory concentrations, the essential oil proved to inhibit the phenotypic expression of five soluble virulence factors (hemolysins, gelatinase, DNase, lipases, and lecithinases). Briefly, the present results showed that the A. annua essential oil contained antimicrobial compounds with selective activity on Gram‐positive and Gram‐negative bacterial strains as well as on yeast strains and which also interfere with the expression of cell‐associated and soluble virulence factors.

Dynamics of Inflammatory Markers in Post-Acute Stroke Patients Undergoing Rehabilitation

Stroke is a pathological condition associated with an enhanced inflammatory response that has a multifactorial etiology. We evaluated the dynamic of plasma concentrations of IL-1α, IL-6, IL-8, TNF-α, soluble form of intercellular adhesion molecule 1, and lipoprotein (a) [Lp(a)] during the rehabilitation of post-acute stroke patients (n = 20), in parallel with control subjects (n = 24). Stroke patients had significantly increased concentrations of IL-6, TNF-α, and Lp(a) when compared to healthy controls. It was found that the changes in the IL-6, IL-8, and TNF-α concentrations associated with the pathological condition were statistically significant (χ2 = 4.81, p = 0.028, χ2 = 10.40, p = 0.005 and χ2 = 6.73, p = 0.034, respectively). The decrease of Lp(a) during the rehabilitation had statistical significance (p = 0.043), while the decrease of IL-1α had marginal significance (p = 0.071). IL-1α, TNF-α, and Lp(a) concentrations were significantly negatively correlated with the Barthel index values, suggesting that the decrease of these inflammatory markers was beneficial for patients’ recovery.

Vaccinium corymbosum L. (blueberry) extracts exhibit protective action against cadmium toxicity in Saccharomyces cerevisiae cells.

Blueberries (Vaccinium corymbosum L.) are a rich source of antioxidants and their consumption is believed to contribute to food-related protection against oxidative stress. In the present study, the chemoprotective action of blueberry extracts against cadmium toxicity was investigated using a cadmium-hypersensitive strain of Saccharomyces cerevisiae. Four varieties of blueberries were used in the study, and it was found that the extracts with high content of total anthocyanidins exhibited significant protective effect against the toxicity of cadmium and H2O2. Both the blueberry extracts and pure cyanidin exhibited protective effects against cadmium in a dose-dependent manner, but without significantly interfering with the cadmium accumulation by the yeast cells. The results imply that the blueberry extracts might be a potentially valuable food supplement for individuals exposed to high cadmium.

Antioxidant activity of rosemary extracts in solution and embedded in polymeric systems

The rosemary extract was encapsulated in polyethylene or in covalently-based network gels. The covalent gels were obtained by the reaction of isocyanate end-capped polyethylene glycol (PEG) with β-cyclodextrin or glycerol. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to evaluate the antioxidant activity (AA) of rosemary extract entrapped in polymeric structures and in ethanol or water solutions. The AA of the rosemary extract was determined using a DPPH radical for samples prepared in ethanol, and a water-soluble derivative, the sulphonated DPPH radical (DPPH-SO3Na), for the rosemary extract in water. Formulation of the rosemary extract in polymeric gels ensures a rapid release which determines the AA values similar to those in solution.

The effect of the ALAnerv nutritional supplement on some oxidative stress markers in postacute stroke patients undergoing rehabilitation.

Stroke is a pathologic condition associated with redox imbalance. This pilot study was designed to evaluate the effect of the consumption of the nutritional supplement ALAnerv on some oxidative stress markers in postacute stroke patients undergoing rehabilitation. To achieve this goal, we assigned 28 patients to 2 study groups: (-)ALA and (+)ALA. Patients in both groups participated in the same rehabilitation program and received comparable standard medications; however, patients in the (+)ALA group received ALAnerv for 2 weeks (2 pills per day). We assessed total and nonproteic thiols, protein carbonyls, ceruloplasmin, oxidized low-density lipoprotein (LDL) particles, lipid hydroperoxide concentrations, gamma-glutamyl transpeptidase activity, and total antioxidant capacity. Regression analysis indicated that supplementation with ALAnerv was responsible for the significant decrease in glucose (p = 0.002) and oxidized LDL particles (p < 0.001) during the study period. For both parameters, the variation in the percent of concentration between the 2 groups during the study period reached statistical significance (p = 0.012 and p < 0.001, respectively). Moreover, Barthel Index values at discharge were significantly influenced by ALAnerv treatment. These preliminary results indicate that ALAnerv might be helpful because it rapidly corrects plasma fasting glucose and corrects serum oxidized LDL particle concentrations, suggesting the need for longer treatment with 2 pills or more per day.

Poly(ethylene glycol)/β-cyclodextrin covalent gel networks: host matrices for studying radical processes in plant extract–riboflavin systems following UV irradiation

Finding new, biocompatible matrices that allow us to model the generation of free radicals is of utmost importance for balancing the harmful and beneficial effects of the latter. In this respect, we report here the simultaneous encapsulation of the radical source and the antioxidant agent in a polyethylene glycol/β-cyclodextrin (PEG/β-CD) covalent gel network. We used electron paramagnetic resonance spectroscopy to evaluate the scavenging action of plant extracts (purple loosestrife, comfrey, milfoil, horsetail, thyme, carob, green coffee) embedded in PEG/β-CD gels. Free radicals were generated in situ by UV irradiation of riboflavin co-embedded in the gels. Prior to this, the extracts were characterized in what concerns their antioxidant activity, and their major polyphenolic constituents were quantified by liquid chromatography-electrospray ionization-tandem mass spectrometry. Purple loosestrife showed the highest antioxidant capacity, followed by comfrey and milfoil. Using the 5,5-dimethyl-1-pyrroline N-oxide spin trap, we have demonstrated that the gel-embedded extracts effectively scavenge the reactive carbon-centered free radicals generated in gel. The PEG/β-CD gels have been shown to be a valuable alternative matrix for the encapsulation of plant active principles having antioxidant activity. Moreover, co-encapsulation of the radical source transforms these gels into a controlled environment in which free radical processes can be tailored.

Antimicrobial and cytotoxic activity of graphene-based perioceuticals

Abstract Globally, periodontitis is one of the most common chronic bacterial infections in the adult population. It is estimated that about 50% of those affected have gingivitis (inflammation and bleeding gums with swelling, reddening, exudate, and change to the normal insertion contour). Current therapeutic strategies are costly, selective, and limited in time. Different approaches have been employed for controlling oral biofilm including prevention of its formation and destruction of the cell biofilm. However, its control requires bacteriostatic agents and antibiofilm strategies for inhibition of initial adherence. In the context of the increased rates of antibiotic resistance, the discovery of active agents against bacteria embedded in biofilm represents an important control strategy for chronic oral diseases; natural products derived from medicinal plants have been proven to be an abundant source of pharmacologically active compounds. Volatile oils, which are products of secondary plant metabolism, are valuable resources for pharmacognostic studies and the development of new therapeutic antiinfectives. This study investigated the application of graphene as a transport and release system for clove oil.