Planta Med 2015; 81 - PW_141
DOI: 10.1055/s-0035-1565765

Leaf structure, metabolic profiling and evaluation of the antimicrobial activity of six mediterranean medicinal plants

S Mamoucha 1, N Tsafantakis 2, T Ioannidis 3, S Chatzipanagiotou 3, C Nikolaou 3, AL Skaltsounis 2, N Fokialakis 2, N Christodoulakis 1
  • 1Faculty of Biology, University of Athens, 15771, Athens, Greece
  • 2Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy, University of Athens, 15771, Athens, Greece
  • 3Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, 11528, Athens, Greece

It is well known that plants develop specific anatomical features and accumulate various secondary metabolites. Those metabolites are part of a major strategy that protects plants from biotic/abiotic stress and contribute to color, scent, flavor etc. However many of them have several application in human health.

In this study the anatomical features, the phytochemical profiling and screening for antimicrobial activity were performed in six medicinal plants found in Greece; Ficus carica, Phillyrea latifolia, Pistacia lentiscus, Euphorbia characias, Globularia alypum and Ricinus communis. Leaves were investigated using Transmission (TEM) and Scanning Electron Microscopy (SEM). Histochemical tests were performed at fresh and fixed tissue. Leaves were extracted and the metabolic profiling was recorded by GC-MS and LC-HRMS and analyzed using in-house and commercial libraries. The antibacterial activity of all extracts was firstly tested by Agar Disc Diffusion method against one Gram-positive (Staphylococcus aureus ATCC29213), one Gram-negative (Escherichia coli ATCC25922), and two clinical strains of Candida albicans. Active extracts were then tested against 26 clinical strains (Pseudomonas aeruginosa, Klebsiella pneumoniae, S. aureus and Streptococcus pneumoniae).

The epidermal, mesophyll cells and the glandular trichomnes of most examined plants showed accumulation of osmiophillic metabolites. Histochemical treatments defined their subcellular localization. SEM micrographs revealed interesting features of trichomnes (glandular and non-glandular). Laticifers were observed at F. carica and E. characias. In the phytochemical study phenolic compounds, steroids, alkaloids, flavonoids, and terpens were detected. Yet, from all the above plant extracts, only those of P. lentiscus had significant activity against S. aureus, P. aeruginosa, S. pneumoniae, and K. pneumoniae.

Acknowledgment: This work was supported by IKY – State Scholarship Foundation, Athens, Greece.