Preparation of nanoparticles containing the extract of Nepeta denudata herb and evaluation of their antimicrobial effects

Abstract

Introduction: Nepeta denudata from¬¬ the Lamiaceae family has anti-microbial, anti-inflammatory, diuretic and other effects. The different parts of N.denudata contain active ingredient such as 1,8-cineole, diterpens, and sesquiterpenes. Therefore, N.denudata selected for preparing its nanoparticle with micro-emulsion method, and improving its morphological properties and anti-microbial effect.Objective: The aim of this study was to evaluation of N.denudata extract and its nanoparticles on the four microorganisms in vitro. Methods: To examine the antibacterial properties of N.denudata plant extract nanoparticles, we first grind the dry powder of the plant. After extracting and crushing the particles at acceptable nano dimensions, we load them inside the solid lipid nanoparticles by the micro-emulsion method. Then, the characterization tests, including particle size, zeta potential, morphological examination, calculation of the amount of drug loaded, and drug leakage, were performed, and necessary in-vitro tests were performed to determine the antibacterial effects of nanoparticles.Results: The particle size was obtained at 60 to 720 nm depending on the lipid (Glycerol monostearate or stearyl alcohol), surfactant (Span80 or Span60 or Brij35), and co-surfactant (Transcutol) used to prepare lipid nanoparticles. Examining the antimicrobial properties of the pure extract of Nepeta denudata and lipid nanoparticles containing this plant extract in-vitro showed that the lipid nanoparticles containing this plant extract improve the antimicrobial effect of this plant extract on three microorganisms of B.subtilis, S.aureus and C.albicans. Also, formulating this extract with lipid nanoparticles can’t delay or slow down the extract's release from the dialysis membrane in vitro.Conclusion: A suitable particle size can be obtained by optimizing the materials used for preparing lipid nanoparticles. Preparing lipid nanoparticles containing the plant extract improves the antimicrobial properties of this plant extract on three microorganisms of B.subtilis, S.aureus and C.albicans.