ABSTRACT
The present study reveals a simple, non-toxic and eco-friendly method for the "green" synthesis of Ag-NPs using hydroponic and soil medicinal plant Stevia rebaudiana extracts, the characterization of biosynthesized nanoparticles, as well as the evaluation of their antibacterial activity. Transmission electronic microscopy (TEM) and Dynamic Light Scattering (DLS) analysis confirmed that biosynthesized Ag-NPs are in the nano-size range (50-100 nm) and have irregular morphology. Biogenic NPs demonstrate antibacterial activity against Escherichia coli BW 25,113, Enterococcus hirae ATCC 9790, and Staphylococcus aureus MDC 5233. The results showed a more pronounced antibacterial effect on E. coli growth rate, in comparison with Gram-positive bacteria, which is linked to the differences in the structure of bacterial cell wall. Moreover, the Ag-NPs not only suppressed the growth of bacteria but also changed the energy-dependent H+-fluxes across the bacterial membrane. The change of H+-fluxes in presence of H+-translocating systems inhibitor, N,N'-dicyclohexylcarbodiimide (DCCD), proves the effect of Ag-NPs on the structure and permeability of the bacterial membrane. Overall, our findings indicate that the Ag-NPs synthesized by medicinal plant Stevia extracts may be an excellent candidate as an alternative to antibiotics against the tested bacteria.
Subject(s)
Metal Nanoparticles , Stevia , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Bacteria , Escherichia coli , Metal Nanoparticles/chemistry , Microbial Sensitivity Tests , Plant Extracts/chemistry , Plant Extracts/pharmacology , Silver/chemistry , Silver/pharmacologyABSTRACT
The biological synthesis of metal nanoparticles using plant extracts with defined size and morphology is a simple, nontoxic and environmentally friendly method. The present study focused on the synthesis of silver nanoparticles (Ag NPs) by Artemisia annua L. extract as reducing and stabilising agent. The Ag NPs function, as antibacterial agents, is with that they are further used in human therapy. The effects of pH and temperature on the synthesis of NPs were characterized by UV-absorption spectroscopy and shown by surface plasmon resonance (SPR) band at 410 nm. NPs' size and morphology were measured by transmission electron microscopy (TEM) and dynamic light scattering (DLS). TEM images showed that Ag NPs were in a nano-sized range (20-90 nm) and had spherical shape. Our findings demonstrated that lower concentration (100 µg mL-1) of the biogenic Ag NPs exhibited antibacterial activity against Gram-negative Escherichia coli BW 25113 and Gram-positive Enterococcus hirae ATCC 9790.
ABSTRACT
Diabetes mellitus (DM) is a serious chronic metabolic disorder. Various diseases are being treated with medicinal plants and that is because of the less side effects of the current therapy. The diversity of plants in Armenia is due to the singularity of natural environment. However, biochemical activity of these plants has not been studied well. Thus, the goal was to investigate biochemical activity and antihyperglycemic properties of Rumex obtusifolius L. in rabbits with hyperglycemia. The high content of total phenolic compounds, flavonoids, and tannins has been determined in this plant extract. Oral administration of ethanol extract showed significant effect on hyperglycemia, reducing fasting glucose levels (57.3%, p<0.05), improving glucose tolerance, and increasing liver glycogen content (1.5-fold, p<0.01) compared to the hyperglycemic control group. Furthermore, ethanol extract of R. obtusifolius reduced total cholesterol, low-density lipoprotein cholesterol levels, and vice versa increased high-density lipoprotein cholesterol levels and also decreased liver enzymes levels (alanine aminotransferase and aspartate aminotransferase) compared with untreated group. These findings suggest that R. obtusifolius may have beneficial effects and should be supplement, as herbal remedy in the treatment of DM.
Subject(s)
Hypoglycemic Agents/pharmacology , Medicine, Traditional , Rumex/chemistry , Seeds/chemistry , Animals , Area Under Curve , Blood Glucose/metabolism , Body Weight/drug effects , Fasting/blood , Glucose Tolerance Test , Glycogen/metabolism , Lipids/blood , Liver/enzymology , Male , Muscles/metabolism , Phytochemicals/analysis , Plant Extracts/pharmacology , Plant Extracts/therapeutic use , RabbitsABSTRACT
Diabetes mellitus (DM) is a serious worldwide problem related to human hyperglycemia. Thus, herbal preparations with antihyperglycemic properties especially leaf extracts of hydroponic Stevia rebaudiana (SR) would be useful in hyperglycemia treatment. The antihyperglycemic potential of this medicinal plant grown using hydroponics methods has been evaluated. Significant reduction of some biochemical characteristics for sugars and fatty acids in blood, liver, and muscle especially fasting glucose levels, serum triglycerides, LDL-cholesterol, total cholesterol levels, and increased HDL-cholesterol ones was shown with SR aqueous extract treatment. Therefore, the aqueous extract of SR is suggested to have antihyperglycemic and antihyperlipidemic activity and to restore liver and muscle glycogen levels (hepatoprotective effects) in hyperglycemia induced by immobilization stress in rabbits and might be recommended for treatment of DM (hyperglycemia).
