Physical, chemical and antimicrobial implications of the association of propolis with a natural rubber latex membrane

Abstract

a b s t r a c tNatural rubber latex (NRL) has shown interesting biomedical properties, such as wound healing improvement, tissue regeneration stimulation and angiogenesis. Propolis, produced by honey bees, acts as an antiseptic agent in beehives. It has been used in ethnopharmacology as an antimicrobial and cicatrizant agent over centuries. The aim of this study was to incorporate propolis into an NRL membrane whilst keeping the antibiotic properties of the former against microorganisms often associated with wound healing delay and the chemical and physical characteristics of the latter. This work has shown that the interactions between the NRL and the propolis constituents were not due to chemical bonding. The propolis-NRL membrane constituents in simulated body fluid were released gradually, reaching 37% release in 144 h. The concentration of released material of 400 lg/mL was able to inhibit 80% of the growth of C. albicans. The incorporation of propolis extract into a NRL membrane while keeping the desirable characteristics of both has been demonstrated to be feasible. Therefore, this association might be used as an auxiliary in wound healing processes.

Preparation and Characterization of UV-Curable Acrylic Membranes Embedding Natural Antioxidants

“…Additionally, propolis powder ( Figure 4, black line) contains discrete bands situated around 2880-2930 cm -1 , attributed to -OH groups which stay in accordance with previously reported data [16,24]. The fingerprint region of both compounds is similar and possess IR bands at about ~1600 cm -1 , 1450 cm -1 and 1100 cm -1 , referring to C=C and C=O groups due to aromatic rings stretching vibrations of polyols, flavonoids and amino acids [16,24,32]. Both systems after UV-curing (green lines) possess bands belonging to polyphenols (3000 and 3600 cm −1 ) and acrylic resin (700-1800 cm -1 ).…”

“…In the black lines of Figure 4 (TP) and Figure 5 (TGP), the wide peak situated between 3000 and 3600 cm -1 is related to the -OH group in molecules forming inter-and intramolecular hydrogen bonds. Additionally, propolis powder ( Figure 4, black line) contains discrete bands situated around 2880-2930 cm -1 , attributed to -OH groups which stay in accordance with previously reported data [16,24]. The fingerprint region of both compounds is similar and possess IR bands at about ~1600 cm -1 , 1450 cm -1 and 1100 cm -1 , referring to C=C and C=O groups due to aromatic rings stretching vibrations of polyols, flavonoids and amino acids [16,24,32].…”

“…It is well known that both tea and propolis are rich in polyphenols and flavonoids, which are clearly visible in their FTIR spectra [16,31]. In the black lines of Figure 4 (TP) and Figure 5 (TGP), the wide peak situated between 3000 and 3600 cm -1 is related to the -OH group in molecules forming interand intramolecular hydrogen bonds.…”

“…No evident changes in other peaks of the original resin could be observed, which suggests that only physical interactions are established between Ebecryl and the fillers; this is desirable if their efficient release from the membrane is sought. It is well known that both tea and propolis are rich in polyphenols and flavonoids, which are clearly visible in their FTIR spectra [16,31]. In the black lines of Figure 4 (TP) and Figure 5 (TGP), the wide peak situated between 3000 and 3600 cm -1 is related to the -OH group in molecules forming inter-and intramolecular hydrogen bonds.…”

“…Moreover, given the strong biological potential of these products, extensive research is in progress, concerning their incorporation into membranes and polymeric materials, to both protect these natural products from early oxidation and inactivation and allow their gradual release, as well as for them to perform antioxidant and antibacterial activity towards the polymer itself. For instance, they were applied as antimicrobials and antioxidants in natural rubber [15,16]. An incorporation of natural anti-oxidant products into i.e., thin films gives a possibility to various application in medicine and industry.…”