Planta Med 2011; 77 - PL20
DOI: 10.1055/s-0031-1282669

Lavandula luisieri pharmacognostic studies and antimicrobial activity against Mycobacterium smegmatis

MD Feijão 1, N Oliveira 2, AM Madureira 2, A Duarte 2, AI Correia 3, G Teixeira 4
  • 1Universidade de Lisboa, Faculdade de Ciências de Lisboa, Departamento de Biologia Vegetal, C2, Campo Grande, 1749–016 Lisboa, Portugal
  • 2Universidade de Lisboa, Faculdade de Farmácia de Lisboa, iMed Universidade de Lisboa, Avenida Prof. Gama Pinto, 1649–003, Lisboa, Portugal
  • 3Universidade de Lisboa, Faculdade de Ciências de Lisboa, Centro de Biologia Ambiental, C2, Campo Grande, 1749–016 Lisboa, Portugal
  • 4Universidade de Lisboa, Faculdade de Farmácia de Lisboa, Centro de Biologia Ambiental, Avenida Prof. Gama Pinto, 1649–003, Lisboa, Portugal

Lavandula luisieri (Rozeira) Rivas-Martinez is a Lamiaceae endemic in Iberian Peninsula (1). The morphology and histochemistry of vegetative and reproductive structures of specimens collected in SW Portugal, during 2007–2010, were investigated by LM and SEM. Non-glandular multi-cellular branched stellate hairs and peltate and capitate I and II, glandular hairs were identified on those structures. Glandular hairs exhibit different secretory modes and almost all showed mixed secretions, hydrophilic and lipophilic in their nature, except peltate hairs, where lipophilic secretions prevail. A preliminary phytochemical screening through TLC on silica gel plates on ascending polarity plant extracts confirmed the results of the histochemical tests: phenolics, flavonoids and terpenes were present and alkaloids were absent.

The antibacterial activity of L. luisieri extracts was determined against different bacteria responsible for infectious diseases in human: Gram-positive bacteria (Staphylococcus aureus ATCC 6538, S. epidermidis ATCC 12228, Enterococcus faecalis ATCC 51299); Gram-negative bacteria (Salmonella typhimurium ATCC 13311, Klebsiella pneumoniae ATCC 9997, Pseudomonas aeruginosa ATCC 9027) and the alcohol-acid resistant bacillus Mycobacterium smegmatis ATCC 19016. Appropriate antibiotics were used as positive controls. All extracts exhibited low activity against Gram-negative bacteria (MICs >125µg/mL) and were active against Staphylococcus aureus. The n-hexane extract inhibited S. typhimurium at a concentration of 62µg/mL; while the dichloromethane and methanol extracts showed the same MIC value of 62µg/mL for Gram-positive bacteria. Dichloromethane, methanol and water extracts inhibited the Mycobacterium smegmatis bacillus growth with MICs of 32, 15 and 32µg/mL, respectively. These results are strongly promising and are worthy of further studies.

Acknowledgement: Telmo Nunes, Paula Paes

References: 1. Morales R (2000) Portugaliae Acta Biol 19: 31–48