Deep blue anthocyanins from blue Dianella berries.

Three anthocyanins, all acylated delphinidin 3,7,3',5'-tetraglucosides, and a naphthalene glycoside, 2-acetyl-1,5-dihydroxy-3 methyl-8-O(xylosyl-(1-->6)-glucosyl) naphthalene, have been isolated from the berries of two Dianella species, D. nigra and D. tasmanica. The anthocyanins show exceptional blueness at in vivo pH values due to effective intramolecular copigmentation involving p-coumaroyl-glucose units (GC) at the 7, 3' and 5' of the delphinidin anthocyanidin. Evidence is presented to show that the effectiveness of the copigmentation can be ranked; 3',5' GC>7 GC>3 GC.

Anthocyanic vacuolar inclusions--their nature and significance in flower colouration.

The petals of a number of flowers are shown to contain similar intensely coloured intravacuolar bodies referred to herein as anthocyanic vacuolar inclusions (AVIs). The AVIs in a blue-grey carnation and in purple lisianthus have been studied in detail. AVIs occur predominantly in the adaxial epidermal cells and their presence is shown to have a major influence on flower colour by enhancing both intensity and blueness. The latter effect is especially dramatic in the carnation where the normally pink pelargonidin pigments produce a blue-grey colouration. In lisianthus, the presence of large AVIs produces marked colour intensification in the inner zone of the petal by concentrating anthocyanins above levels that would be possible in vacuolar solution. Electron microscopy studies on lisianthus epidermal tissue failed to detect a membrane boundary in AVI bodies. AVIs isolated from lisianthus cells are shown to have a protein matrix. Bound to this matrix are four cyanidin and delphinidin acylated 3,5-diglycosides (three, new to lisianthus), which are relatively minor anthocyanins in whole petal extracts where acylated delphinidin triglycosides predominate. Flavonol glycosides were not bound. A high level of anthocyanin structural specificity in this association is thus implied. The specificity and effectiveness of this anthocyanin "trapping" is confirmed by the presence in the surrounding vacuolar solution of only delphinidin triglycosides, accompanied by the full range of flavonol glycosides. "Trapped" anthocyanins are shown to differ from solution anthocyanins only in that they lack a terminal rhamnose on the 3-linked galactose. The results of this study define for the first time the substantial effect AVIs have on flower colour, and provide insights into their nature and their specificity as vacuolar anthocyanin traps.

Covalently linked anthocyanin-flavonol pigments from blue Agapanthus flowers.

The structures of the two major anthocyanins in blue Agapanthus flowers have been determined to be a p-coumaroylated delphinidin diglycoside attached to a flavonol triglycoside via a succinic acid diester link. The structure has been determined unambiguously through degradation studies, glycosidic analysis and NMR experiments. These compounds represent unique examples of anthocyanin pigments where both types of co-pigment, an aromatic acyl group and a flavonoid co-pigment, are attached covalently to the anthocyanin.

An antimicrobial kaempferol-diacyl-rhamnoside from Pentachondra pumila.

An extract of Pentachondra pumila yielded a new compound, kaempferol 3-(2,4-di-E-p-coumaroylrhamnoside) as the antimicrobially active component. Analysis of 13 other extracts of various New Zealand Epacridaceae species revealed this compound to be a constituent of all but one.

Cytotoxic saponins from New Zealand Myrsine species.

The observed biological activity in two New Zealand Myrsine species has been shown to be due to the presence of triterpene saponins. From Myrsine australis a series of eight oleanane-type saponins was obtained, with compounds 1-4 and 7 and 8 being novel. Also isolated were ardisiacrispin A [5] and ardisiacrispin B [6]. The structures of the new compounds were determined by chemical and spectroscopic techniques. Extracts of Myrsine salicina yielded only one saponin, 5. Saponins 1-8 were shown to be combinations of four oleanane triterpenes bonded to beta-D-xylp(1-->2)-beta-D-glcp(1-->4)-[beta-D-glcp(1-->2)]-alpha-L -arap (compounds 1, 3, 5, 7) and this same tetrasaccharide with alpha-L-rhap replacing the beta-D-xylp unit (compounds 2, 4, 6, 8).

Antiviral phloroglucinols from New Zealand Kunzea species.

Four acyl-phloroglucinol derivatives showing antiviral activity have been isolated from Kunzea sinclairii and Kunzea ericoides (Myrtaceae) from New Zealand. The structures of these compounds were deduced from analysis of spectral data. Two of these compounds, 1 and 2, are the isomers of isobutyryl methoxyresorcinol. The two new compounds, 3 and 4, were isolated as a mixture and determined to be 4-cyclohexene-1,3-dioxo-5-hydroxy-2,2,6,6-tetramethyl-4- (1-[2,6-dihydroxy-4- methoxy-3-(3-methyl-1-oxobutyl)phenyl]-3-methylbutyl) and its 2-methyl-1-oxopropyl analogue, respectively.

Cytotoxic norditerpene lactones from Ileostylus micranthus.

Three new compounds 2-4 and two known compounds 1 and 5 have been isolated from the cytotoxic fraction of an extract from a New Zealand mistletoe, Ileostylus micranthus. Compounds 1-5 are shown to be norditerpene lactones and have strong cytotoxicity. The compounds are proposed to have been assimilated by the mistletoe from the host tree, Podocarpus totara.

Studies on human lactoferrin by electron paramagnetic resonance, fluorescence, and resonance Raman spectroscopy.

Investigations of metal-substituted human lactoferrins by fluorescence, resonance Raman, and electron paramagnetic resonance (EPR) spectroscopy confirm the close similarity between lactoferrin and serum transferrin. As in the case of Fe(III)- and Cu(II)-transferrin, a significant quenching of apolactoferrin's intrinsic fluorescence is caused by the interaction of Fe(III), Cu(II), Cr(III), Mn(III), and Co(III) with specific metal binding sites. Laser excitation of these same metal-lactoferrins produces resonance Raman spectral features at ca. 1605, 1505, 1275, and 1175 cm-1. These bands are characteristic of tyrosinate coordination to the metal ions as has been observed previously for serum transferins and permit the principal absorption band (lambda max between 400 and 465 nm) in each of the metal-lactoferrins to be assigned to charge transfer between the metal ion and tyrosinate ligands. Furthermore, as in serum transferrin the two metal binding sites in lactoferrin can be distinguished by EPR spectroscopy, particularly with the Cr(III)-substituted protein. Only one of the two sites in lactoferrin allows displacement of Cr(III) by Fe(III). Lactoferrin is known to differ from serum transferrin in its enhanced affinity for iron. This is supported by kinetic studies which show that the rate of uptake of Fe(III) from Fe(III)--citrate is 10 times faster for apolactoferrin than for apotransferrin. Furthermore, the more pronounced conformational change which occurs upon metal binding to lactoferrin is corroborated by the production of additional EPR-detectable Cu(II) binding sites in Mn(III)-lactoferrin. The lower pH required for iron removal from lactoferrin causes some permanent change in the protein as judged by altered rates of Fe(III) uptake and altered EPR spectra in the presence of Cu(II). Thus, the common method of producing apolactoferrin by extensive dialysis against citric acid (pH 2) appears to have an adverse effect on the protein.