The roots of Dianella laevis contain a
crystalline glycoside, dianellin, and the corresponding aglycone, dianellidin.
Only dianellin has been isolated from D. caerulea. Dianellidin is identified as
1,8-dihydroxy-3-methyl-2-acetonaphthone and the glycoside has the sugars,
glucose and rhamnose, attached at the 8-position. Dianellin is readily
converted into plumbagin and is a possible natural precursor of this and other
naphthoquinones found in plants. There is some evidence for the occurrence of
traces of this type of compound in Dianella roots.
Avicennia marina, commonly known as the grey mangrove, is distributed widely along the coast of New South Wales. It is used as a source of tannin in some countries and the very hard timber is used occasionally in boat-building. The bark has now been examined for neutral and acid constituents and was found to contain betulic acid (0 -3 %), taraxerol (0 -06 %), and taraxerone (0.05 %).A minute amount of a hydrocarbon, probably triacontane, was also isolated.
ExperimentalMelting points are uncorrected and were determined in evacuated capillaries. Analyses were carried out by the C.S.I.R.O. Microanalytical Laboratory. Light petroleum refers to the fraction, b.p. 60-80 'C.Chopped, dried bark (3 k g ; collected along the Hunter River, Newcastle, N.S.W.) was extracted continuously with ether for 2 days. The extract (5 1.) was reduced to 11. and shaken with N NaOH. The precipitated sodium salt was filtered off and, without drying, purified by treatment of a solution in 50% alcohol (200 ml) with charcoal followed by acidification. The crude acid was dissolved in a 5% solution of KOH in 50% alcohol (200 ml), the solution treated with charcoal and then acidified. Recrystallization from methanol gave 8 . 5 g of betulic acid, m.p. 308-310 OC,
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