Chemical composition of the leaf oil from Baccharis punctulata DC. at two phenological stages

ABSTRACT

Leaf oil of male Baccharis punctulata DC. from Argentina was analyzed at vegetative and at flowering stage. Compound identification and differences are reported. The major component at vegetative stage (42-48%) was identified as the rare furanocadinane verboccidentafuran. 13C-NMR data of verboccidentafuran are assigned for the first time. Other components are δ-elemene (9.1%), β-elemene (3.1%), amorpha-4,7(11)-diene (7.5%), β-bisabolene (2.4%), δ-cadinene (2.5%), cis-cadin-4-en-7α-ol (5.0%), α-muurolol (2.8%), α-cadinol (2.0%) and α-bisabolol (2.7%). At flowering stage, oils showed two major components: verboccidentafuran (22.4%) and the infrequent germacra-1(10),5-dien-4α-ol (17.3%) which  was unambiguously differentiated from the 4β-ol diastereoisomer. Other components are (E)-β-ocimene (2.4%), linalool (2.5%), δ-elemene (8.6%), β-elemene (3.3%), amorpha-4,7(11)-diene (2.3%), elemol (2.6%), guaiol (2.4%), cis-cadin-4-en-7α-ol (6.4%), α-muurolol (3.4%) and α-bisabolol (2.3%). Female plant leaf oils showed similar tendency. All oils were sesquiterpene-rich. Different composition is associated with flowering. Major compounds are reported in B. punctulata for the first time.

KEYWORDS:

• Baccharis punctulata essential oil
• phenological variation
• verboccidentafuran
• germacra-1(10), 5-dien-4α-ol

Acknowledgments

I would like to thank Dr. Daniel Giuliano for his help by identifying the plant materials and to Dr. Lucas Fabian for the Nuclear Magnetic Resonance spectra. I also thank the Basic Science Department of the National University of Luján for financially supporting this investigation.

Disclosure statement

No potential conflict of interest was reported by the author.