Comparison of the essential oil composition of fourPlagiochila species:P. bifaria,P. maderensis,P. retrorsa andP. stricta

Abstract

Essential oils isolated by distillation-extraction from P. bifaria, P. maderensis, P. retrorsa and P. stricta, collected on Madeira, were analysed by GC and GC-MS. Methyl everninate (1-35%), peculiaroxide (13-16%) and enteudesm-4(15)-ene-6-one (9-19%) were the main components in all P. bifaria specimens analysed. Terpinolene (34-60%) dominated the oils isolated from P. maderensis specimens. β β β β β-Phellandrene (16-46%) was the main component of two of the three specimens of P. retrorsa, allo-ocimene (15%), terpinolene (13%), peculiaroxide (12%) and neo-allo-ocimene (10%) being the main components of the third specimen. P. stricta oils were dominated by peculiaroxide (11-21%), allo-ocimene (7-19%), bicyclogermacrene (4-17%), neo-allo-ocimene (4-11%) and spathulenol (2-14%). Essential oil cluster analysis showed a high degree of similarity between three of the four species studied, the least correlated being P. maderensis oils.

Chemotaxonomic value of essential oil components in liverwort species. A review

“…[11] In addition to a large wileyonlinelibrary.com/journal/ffj amount of compound 52, P. bifaria from Madeira produces the 9,10-dihydrophenanthrenes, 53 and 54, and the methyl benzoates, 55 and 56. [53,54] Compounds 55 and 56 were also detected in P. retrorsa and P. stricta, which also belong to this chemotype. [53] In the EOs obtained from P. maderensis the presence of methyl everninate (52) also confirmed [53] this liverwort species was classified in chemotype VI, which produce bibenzyls as the major components.…”

“…[53,54] Compounds 55 and 56 were also detected in P. retrorsa and P. stricta, which also belong to this chemotype. [53] In the EOs obtained from P. maderensis the presence of methyl everninate (52) also confirmed [53] this liverwort species was classified in chemotype VI, which produce bibenzyls as the major components. [11] Rycroft et al [55] have analysed the solvent extracts obtained from two collections of P. maderensis and detected 4-hydroxy-3'-methoxybibenzyl (57) as the major volatile component.…”

“…In the case of P. stricta, the major monoterpenoids were allo-ocimene (59) (6.7-19.1%) and neoallo-ocimene (60) (3.7-10.5%). [53] The EO of the German liverwort P. asplenioides showed the presence of 2,3-secoaromadendrane-type sesquiterpenoids. Plagiochilines W (62) and X (63) were detected among the other components of the EOs ( Figure 5).…”

“…[11] The analysis of the EO composition of four Plagiochila species from Madeira showed that these species are characterized by the absence of 2,3-seco-aromadendrane-type sesquiterpenoids. [53] Type XII of the Plagiochila species is characterized by the occurrence of everninic acid methyl ester (52) together with a wide range of other aromatic compounds, especially 9,10-dihydrophenanthrenes. [11] In addition to a large wileyonlinelibrary.com/journal/ffj amount of compound 52, P. bifaria from Madeira produces the 9,10-dihydrophenanthrenes, 53 and 54, and the methyl benzoates, 55 and 56.…”

“…This compound was absent in the EO from this liverwort species. [53] The Madeiran P. maderensis, R. retrorsa and P. stricta are also rich sources of monoterpenoids. Plagiochila maderensis contained terpinolene (58) (33.5-60.0%), while P. retrorsa produced allo-ocimene (59) (4.9-15.0%), neo-alloocimene (60) (4.2-9.6%), β-phellandrene (61) (5.5-46.9%) and terpinolene (58) (12.9%).…”