The present work describes the development of a nanocomposite system and its application in construction of a new amperometric biosensor applied in the determination of total polyphenolic content ...from propolis extracts. The nanocomposite system was based on covalent immobilization of laccase on functionalized indium tin oxide nanoparticles and it was morphologically and structural characterized. The casting of the developed nanocomposite system on the surface of a screen-printed electrode was used for biosensor fabrication. The analytical performance characteristics of the settled biosensor were determined for rosmarinic acid, caffeic acid and catechol (as laccase specific substrate). The linearity was obtained in the range of 1.06×10
−6
− 1.50×10
−5
mol L
−1
for rosmarinic acid, 1.90×10
−7
− 2.80×10
−6
mol L
−1
for caffeic acid and 1.66×10
−6
− 7.00×10
−6
mol L
−1
for catechol. A good sensitivity of amperometric biosensor 141.15 nA µmol
−1
L
−1
and fair detection limit 7.08×10
−8
mol L
−1
were obtained for caffeic acid. The results obtained for polyphenolic content of propolis extracts were compared with the chromatographic data obtained by liquid-chromatography with diode array detection.
Propolis, which has been used widely in folk medicine, has been shown to exhibit various biological activities but its immunoregulatory and anti-inflammatory activities in intact animals have not ...been well studied. We investigated these activities of propolis using an ovalbumin-induced asthma animal model. Mice were immunized and sensitized by exposure to ovalbumin (OVA) antigen and administered with low- (65
mg/kg body weight) and high-dose (325
mg/kg body weight) propolis water extracts by tube feeding. The serum OVA-specific IgE titer and cytokine profiles in cultured splenocytes and bronchoalveolar lavage fluids (BALF) were analyzed. The number of eosinophils in BALF was counted. Here we demonstrate that propolis extracts can suppress the serum levels of OVA-specific IgE and IgG
1, and airway hyperresponsiveness (AHR) in OVA-sensitized mice. There are no significant differences in the concentration of eotaxin or the number of eosinophils in BALF among the four groups. However, the higher dose of propolis extracts decreases the level of IL-5 in BALF. The splenocytes from mice administered with propolis extracts (low- and high-dose groups) exhibit a strong inhibition of IL-10 secretion and up-regulation of IFN-γ secretion in splenocytes stimulated with concanavalin A (ConA). In addition, cytokine (IFN-γ, IL-6, and IL-10) secretion in OVA-stimulated splenocytes from the propolis groups was significantly lower than that in the control group. These results suggest that propolis extracts may be a potential novel therapeutic agent for asthma.
Some commercial extracts of propolis obtained with different solvents were tested to evaluate their antibacterial and antifungal activity. All propolis preparations exhibited antimicrobial activity, ...particularly against Gram‐positive bacteria, yeasts and dermatophytes with zones of inhibition ranging from 3 to 30 mm. Against yeasts and dermatophytes, oil, ethanol and propylene glycol solutions showed an inhibition for more 2 weeks, while the glycerine solution maintained inhibition only for some days. The results indicate that the solvent employed for the extraction may enhance the potency of the antimicrobial activity of propolis. Consistency in the properties and characteristics of propolis were related to the formulation of extraction procedures.
This work has examined the hot-pressurized fluid extraction of seven flavonoids, caffeic acid phenethyl ester and four phenolic acids from Brazilian propolis lumps generating, during the process, ...fat- and water-soluble extracts. The solid content of water-soluble extract obtained by hot-pressurized water in the presence of 29% natural surfactant was 35.2
mg/mL and was 44% greater than that obtained without natural surfactant. Furthermore the amount of the seven flavonoids and caffeic acid phenethyl ester in the fat-soluble extract exceeded those in the water-soluble sample while, on the other hand, the amount of the four phenolic acids in the water-soluble extract was more than those in the fat-soluble extract. Our findings show that the total solid content and the amount of these 12 active compounds produced by the emulsified hot-pressurized water are 36% and 7% higher, respectively, than those produced by emulsified water at atmospheric pressure. The EC
50 value of the free radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl of the emulsified hot-pressurized water extract was the lowest, and presented the strongest anti-oxidation ability among all the extracts.
In vitro cytotoxicity indicated that the water-soluble extract strongly suppressed the growth of leukemia (HL-60, U937), lung cancer (A549, CH27) and liver cancer (Hep G2, Hep 3B) cells in a concentration-dependent behavior.
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