Superoxide-producing lipoprotein fraction from Stevia leaves: definition of specific activity

Abstract

Background Stevia rebaudiana Bertoni has various pharmacological actions, which includes antidiabetic, antioxidant, anti-inflammatory activities. The superoxide and consequently NADPH oxidase (Nox) are relevant targets involved in biological effects of Stevia. The presence of NADPH-containing superoxide-producing lipoprotein (suprol) in Stevia leaves has not yet been tested. The mechanism of producing superoxide radicals (O 2 − ) by suprol was determined in vitro, which is associated with the electron transfer from NADPH in the composition of suprol by traces of transition metal ions (Fe 3+ or Cu 2+ ) to molecular oxygen, turning it into O 2 − . It is expected that the therapeutic efficacy of Stevia leaves is caused by specific activity of superoxide-producing lipoprotein fraction. Methods For the first time, from the dry leaves of Stevia the NADPH-containing superoxide-producing lipoprotein was isolated and purified. The specific content of suprol (milligrams in 1 g of Stevia leaves- mg/g) was determined after desalination of suprol and lyophilization. Results According to the method provided, the specific content of the isolated suprol from Stevia’s leaves was up to 4.5 ± 0.2 mg / g (yields up to 68.5 ± 4.7%, p < 0.05, n = 6). Nox forms a stable complex with suprol. The optical absorption spectrum of the Nox-suprol complex represents the overlapping suprol and Nox spectra, with a certain background increase and characteristic features of optical absorption for Nox. Due to O 2 − producing capacity suprol-Nox complex discolors KMnO 4 solutions, Coomassie brilliant blue, restores nitrotetrazolium blue to formazan and oxidizes epinephrine to adrenochrome. The oxidation activity of adrenaline is 50.3 ± 5.1 U / mg / ml ( p < 0.05, n = 6). Conclusion Superoxide-producing lipoprotein fraction-Nox complex from Stevia leaves (membranes) can modulate redox regulated signaling pathways and may play a positive role in type-2 diabetes by means of adrenaline oxidation mechanism.

Effects of stevia on synaptic plasticity and NADPH oxidase level of CNS in conditions of metabolic disorders caused by fructose

“…Selective complex formation between Hb and Nox isoforms was proved in three independent ways: formation of S-nitrosohemoglobin, capture of traces of Hb in suprol (superoxide-producing lipoprotein of serum [ 39 ]) and complex deposition on cellulose DE-52 [ 61 – 63 ]. Hb-induced releasing of Nox isoforms of total fraction from heterogeneous phase (from biomembranes) in soluble phase occurs through this complex formation.…”

“…and spinal cord and brain were removed (hippocampus and amygdala were disassociated from the skull). For the production of antibodies during Nox isolation a detergent is used which denatures the enzyme (associated with it) to a certain degree [ 39 ]. To prevent this denaturation, a simple method has been developed for isolation of fractions of combined isoforms or single Nox isoforms from cellular and intracellular membranes and nanoparticles of membrane formation-mammalian exosomes, excluding the use of detergent.…”

The Effect of Foliar Selenium (Se) Treatment on Growth, Photosynthesis, and Oxidative-Nitrosative Signalling of Stevia rebaudiana Leaves

“…NADPH-containing superoxide producing NOX enzyme in Stevia rebaudiana has recently been characterized [ 98 ]. In agreement with this, a single specific enzyme band was detectable in native gel ( Figure 6 C).…”

Entropy - System Approach to Assess the Ecological Status of Reservoirs in Armenia

“…Then, in the equation Shannon Pi-probability of the number of cases of MPC excess of i-substance or water indicator of total cases of MPC -N, Pi = ni /N. For determineation the values of the GEVORG index and Armenian index of environmental quality, the following computational algorithm is used [17][18][19]:…”

“…As a result of anthropogenic pollution of the aquatic environment, the entropy of the system changes, which is not always taken into account in hydrochemical studies. For assessing the quality of surface water and environmental pollution, we recently propose the entropy Geo-Ecological Evolving Organized Index (GEVORG) (G) and the Armenian Water Quality Index (AWQI) [17][18][19] The purpose of this article is to assess the water quality of the reservoirs of Lake Arpi, Lake Yerevan, Akhurian, Azat, Aparan and Kechut by using the Armenian Water Quality Index.…”