The chemical constituents of Idiospermum australiense (Diels) S.T. Blake – Part 2

In the first post I discussed the alkaloids that were extracted from the plant. A subsequent post discussed the structure of a new triterpene lactone that was extracted. This post will discuss the other substances that were identified from the plant.

Of the substances that merit mention -

The bark afforded:

The coumarin scopoletin 1.0%
The flavone glycoside hesperidin 2.0%
β-sitosterol 0.01%


The seeds or cotyledons afforded:

Hesperidin 0.5%
Scopoletin 0.2%
p-hydroxybenzaldehyde 0.05%


The wood afforded:

The flavone hesperetin 0.05%
Scopoletin 0.14%
Scopoletin methyl ether 0.03%


The leaves afforded:

Hesperetin 0.05%
The flavone diosmetin 1.5 x 10-3%
The flavone acacetin 1.5 x 10-3%
A sesquiterpene hydrocarbon (C15H24) 0.38%

Because of time constraints, further investigative work on the sesquiterpene hydrocarbon was not carried out.

The Australian researchers, Brophy and Goldsack have examined the essential oils in Idiospermum australiense. Their results are as follows:

The leaf essential oil obtained from Idiospermum australiense (Diels) S. T. Blake in 0.3-0.5% yield (based on fresh weight) consisted of monoterpenes and sesquiterpenes. Of the 41 compounds detected in amounts >0.05%, the principal components were bicyclogermacrene (48%) and caryophyllene (8%). The tricyclic sesquiterpene alcohols globulol, viridiflorol and spathulenol were also present each in approximately 5% amounts – Jospeh J. Brophy and Robert J. Goldsack Flavour and Fragrance Journal, vol. 7 (1992), pp79-80).

Both bicyclogermacrene and caryophyllene are sesquiterpenes with the molecular formula C15H24.

D.A. Young and R.W. Sterner, Biochem. Syst. Ecol.vol. 9 (1981), p185 have examined the flavonoids in the leaves of Idiospermum australiense. Their results are cited by Robert Hegenauer in his “Chemotxonomie der Pflanzen: eine Übersicht über die Verbreitung und die sysstematische Bedeutung der Pflanzenstoffe” vol. VIII on p109. Hegenauer notes that Young and Sterner refer to the presence of 7-glucosides of luteolin and apigenin.

Our results revealed the presence of the 7- glycoside, hesperidin, and its aglycone hesperetin together with diosmetin and acacetin. Diosmetin is a methyl derivative of luteolin while acacetin is a methyl derivative of apigenin. Hesperetin is the flavanone from diosmetin.