Effect of Encapsulation on Antimicrobial Activity of Herbal Extracts with Lysozyme

Resistance of microorganisms to antibiotics has increased. The use of natural components with antimicrobial properties can be of great significance to reduce this problem. The presented work is focused on the study of the effect of encapsulation of selected plant and animal antimicrobial substances (herbs, spices, lysozyme and nisin) on their activity and stability. Antimicrobial components were packaged into liposomes and polysaccharide particles (alginate, chitosan and starch). Antimicrobial activity was tested against two Gram-positive (Bacillus subtilis and Micrococcus luteus) and two Gram-negative (Escherichia coli and Serratia marcescens) bacteria. Encapsulation was successful in all types of polysaccharide particles and liposomes. The prepared particles exhibited very good long-term stability, especially in aqueous conditions. Antimicrobial activity was retained in all types of particles. Liposomes with encapsulated herb and spice extracts exhibited very good inhibitory effect against all tested bacterial strains. Most of herbal extracts had very good antimicrobial effect against the tested Gram-negative bacterial strains, while Gram-positive bacteria were more sensitive to lysozyme particles. Thus, particles with co-encapsulated herbs and lysozyme are more active against different types of bacteria, and more stable and more effective during long-term storage. Particles with encapsulated mixture of selected plant extracts and lysozyme could be used as complex antimicrobial preparation with controlled release in the production of food and food supplements, pharmaceutical and cosmetic industries.
Posljednjih se godina otpornost mikroorganizama na antibiotike povećala, što bi se moglo prevladati uporabom prirodnih sastojaka s antimikrobnim svojstvima. Težište ovoga rada je na ispitivanju utjecaja enkapsulacije odabranih antimikrobnih spojeva iz biljaka i životinja (ekstrakti ljekovitog bilja i začina, lizozim i nizin) na njihovu aktivnost i stabilnost. Antimikrobni spojevi su prevučeni liposomima ili ugljikohidratima (alginatom, kitozanom ili škrobom). Njihova antimikrobna aktivnost ispitana je na dvije Gram-pozitivne (Bacillus subtilis i Micrococcus luteus) i dvije Gram-negativne bakterije (Escherichia coli i Serratia marcescens). Enkapsulacija je svih uzoraka bila uspješna, a pripremljene su čestice imale jako dobru i dugotrajnu stabilnost, naročito u vodenom mediju, a pritom su zadržale antimikrobnu aktivnost. Liposomi s ekstraktima ljekovitog bilja i začina vrlo su uspješno suzbijali rast svih vrsta bakterija. Većina je ekstrakata ljekovitog bilja imala jako dobar antimikrobni učinak na ispitane Gram-negativne bakterije, dok su Gram-pozitivne bakterije bile osjetljivije na čestice lizozima. Stoga je zaključeno da su čestice s ekstraktima ljekovitog bilja i lizozima prikladnije za suzbijanje različitih tipova bakterija, a osim toga su stabilnije i zadržavaju aktivnost tijekom duljeg perioda skladištenja. Čestice enkapsuliranih ekstrakata biljaka i lizozima mogu se upotrijebiti kao složeni antimikrobni preparati s kontroliranim otpuštanjem aktivnih tvari u proizvodnji hrane, dodataka hrani, farmaceutskoj i kozmetičkoj industriji.