Volatile-oils composition, and bioactivity of the essential oils of Plectranthus barbatus, P. neochilus, and P. ornatus grown in Portugal.
Volatile-oils chemical composition and bioactivity of the essentail oils from Plectranthus barbatus, P. neochilus, and P. ornatus (Lamiaceae) were assessed. Aerial parts from these three related Plectranthus species were collected from cultivated plants grown in Portugal, during vegetative and flowering phases. Volatiles, isolated by distillation-extraction, were analyzed by GC and GC/MS. Monoterpene hydrocarbons (12-74%) and sesquiterpene hydrocarbons (4-45%) constituted the main fractions in all volatiles. α-Pinene (3; 12-67%), oct-1-en-3-ol (6; traces-28%), β-pinene (7; 0.1-22%), and β-caryophyllene (50; 7-12%) dominated P. barbatus volatiles. P. neochilus major volatile components were α-terpenyl acetate (41; traces-48%), α-thujone (2; 2-28%), β-caryophyllene (50; 2-28%), β-pinene (7; 1-25%), and α-pinene (3; 1-19%). Oct-1-en-3-ol (6; 13-31%), β-pinene (7; 11-24%), α-pinene (3; 11-19%), and β-caryophyllene (50; traces-11%) were the main constituents from P. ornatus volatiles. These chemical compositions were rather different from those previously found for specimens harvested in Africa and Brazil. Moreover, the volatiles from the flowers are herewith reported for the first time. Essential oils, isolated by hydrodistillation from leaves and stems, showed a yellowish color and unpleasant odor, with yields ranging from 0.08% to 0.84% (v/dry weight). Antioxidant and antimicrobial activities of the essential oils were evaluated by DPPH· and TBARS assays, and agar disc-diffusion method, respectively. Results showed low or moderate antioxidant capacity and significant antimicrobial activity against Gram-positive bacteria.
Universidade de Lisboa, Faculdade de Ciências de Lisboa, Departamento de Biologia Vegetal, Centro de Biotecnologia Vegetal, IBB, Campo Grande, PT-1749-016 Lisboa, (phone: +351 21 750 00 00; fax: +351 21 750 00 48).
Luísa
L
Mota
A Cristina
AC
Figueiredo
Luís G
LG
Pedro
José G
JG
Barroso
M Graça
MG
Miguel
M Leonor
ML
Faleiro
Lia
L
Ascensão
D000890:Anti-Infective Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D000975:Antioxidants / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D001424:Bacterial Infections / Q000188:drug therapy; D005658:Fungi / Q000187:drug effects; D006801:Humans; D009181:Mycoses / Q000188:drug therapy; D009822:Oils, Volatile / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D010938:Plant Oils / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D031346:Plectranthus / Q000737:chemistry*
D000890:Anti-Infective Agents; D000975:Antioxidants; D009822:Oils, Volatile; D010938:Plant Oils
Antimicrobial activity; Antioxidant activity; Essential oils; Plectranthus species