|
Morphological and chemical
composition of the essential oil of the leaf of
Schistostephium heptalobium
Mayekiso Buyisile
Botany
Department, University of Fort Hare, Private Bag X1314,
Alice, Eastern Cape, South Africa. E-mail:
bmayekiso@ufh.ac.za
or mayekiso@yahoo.com.
Tel.: +27 406022324. Fax: +27 8066 282 325.
Accepted
10 February, 2009 |
|
The morphology of Schistostephium heptalobium was
investigated by using electron microscopical examination.
The scanning electron microscope revealed that the leaves of
this plant are characterized by short, multicellular
glandular trichomes and long hairy-fibrous tubular
non-glandular trichomes. These trichomes are associated with
crystal-like deposits. The Scanning Electron
Microscopy-Energy Dispersive Spectroscopy (SEM-EDX) showed
that, Fe, Al, K, Mg and Si are the major components of the
crystals-like deposits. The area of the non-glandular
trichomes where these crystals-like substances are produced
showed Al, Ca, K, Mg, Mo, Na, Pi and Si as major residue
when analysed by SEM-EDX. However, the SEM-EDX analysis of
glandular trichome sac and the content of the sac showed
different results. The anatomical investigation also showed
that the ends of the non-glandular trichomes are fibrous and
have a tubular base while the glandular trichomes contain
cuticular sac. The sac contains by products which are
referred to as essential oil. These by-products are regarded
as the first line of defence in this plant.
Hydro-distillation of fresh leaves of S. heptalobium
yielded 2.5% (v/v) of the essential oil. The GC-MS analysis
of the oil revealed that the essential oil of S.
heptalobium is characterized by α-pinene, sabinene,
myrcene, α-phellendrene, 1.8-cineole, γ-terpinen, α-thujone,
cis-sabinene hydrate, camphene, terpinen-4-ol, α-terpineol,
2-cyclohexen-1one, geranial, phenol, neryl acetate, β-caryophyllene,
β-selinene and caryophyllene oxide.
Key
words:
Glandular trichomes, non-glandular trichomes, SEM-EDX
analysis, essential oil composition, Schistostephuim
heptalobium. |
