Pharmaceuticals (Apr 2021)

Antimicrobial and Immunomodulating Activities of Two Endemic <em>Nepeta</em> Species and Their Major Iridoids Isolated from Natural Sources

  • Neda Aničić,
  • Uroš Gašić,
  • Feng Lu,
  • Ana Ćirić,
  • Marija Ivanov,
  • Bojan Jevtić,
  • Milena Dimitrijević,
  • Boban Anđelković,
  • Marijana Skorić,
  • Jasmina Nestorović Živković,
  • Yingle Mao,
  • Jia Liu,
  • Chunping Tang,
  • Marina Soković,
  • Yang Ye,
  • Danijela Mišić

DOI
https://doi.org/10.3390/ph14050414
Journal volume & issue
Vol. 14, no. 5
p. 414

Abstract

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Two Balkan Peninsula endemics, Nepeta rtanjensis and N. argolica subsp. argolica, both characterized by specialized metabolite profiles predominated by iridoids and phenolics, are differentiated according to the stereochemistry of major iridoid aglycone nepetalactone (NL). For the first time, the present study provides a comparative analysis of antimicrobial and immunomodulating activities of the two Nepeta species and their major iridoids isolated from natural sources—cis,trans-NL, trans,cis-NL, and 1,5,9-epideoxyloganic acid (1,5,9-eDLA), as well as of phenolic acid rosmarinic acid (RA). Methanol extracts and pure iridoids displayed excellent antimicrobial activity against eight strains of bacteria and seven strains of fungi. They were especially potent against food-borne pathogens such as L. monocytogenes, E. coli, S. aureus, Penicillium sp., and Aspergillus sp. Targeted iridoids were efficient agents in preventing biofilm formation of resistant P. aeruginosa strain, and they displayed additive antimicrobial interaction. Iridoids are, to a great extent, responsible for the prominent antimicrobial activities of the two Nepeta species, although are probably minor contributors to the moderate immunomodulatory effects. The analyzed iridoids and RA, individually or in mixtures, have the potential to be used in the pharmaceutical industry as potent antimicrobials, and in the food industry to increase the shelf life and safety of food products.

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