Graham P. Jones

Amino acid and glycine betaine accumulation in cold-stressed wheat seedlings

Abstract The changes in amino acid and glycine betaine content in response to cold stress (4°) in wheat seedlings were investigated using HPLC and NMR. Glutamine, proline, 4-aminobutyric acid, alanine, aspartic acid, asparagine, glycine, glycine betaine, valine, threonine and isoleucine levels increased while glutamic acid content decreased. These changes were not accompanied by a reduction in leaf water potential. Possible mechanisms of accumulation of these solutes are discussed.

Antitumor activity of extract of Zingiber aromaticum and its bioactive sesquiterpenoid zerumbone

The anticancer properties of zerumbone (2,6,9 humulatriene-8-one, a sesquiterpenoid) from Zingiber aromaticum were compared with those of curcumin from Curcuma longa in an in vitro MTT tetrazolium salt assay using HT-29, CaCo-2, and MCF-7 cancer cells and in an azoxymethane (AOM)-induced animal model of colon cancer using aberrant crypt foci (ACFs) as a preneoplastic marker. The IC50 of zerumbone was approximately 10 μM and that of curcumin was 25 μM. Cell cycle arrest in HT-29 cells was observed at G0/G1 for 10 and 12.5 μMand G2/M for 25 μafter 24 h at concentrations of 10-25 μM of zerumbone, and a concentration-dependent increase in apoptosis (2-6% of viable cells) was observed after 48 h using the same concentration range. Male Sprague-Dawley rats were fed extracts in an AIN diet prepared from the equivalent of 4% by weight of dried rhizomes of Z. aromaticum and C. longa. ACFs were induced by two doses (15 mg/kg body weight) subcutaneously of AOM1 wk apart, the rats were killed 10 wk later, and the ACFs were assessed in the colon. Total ACFs were significantly reduced by Z. aromaticum extract (down 21%, P < 0.05) relative to control, the effect being most evident with large ACFs (≥3 aberrant crypts per focus). Similar reductions were observed with 4% C. longa extract in the diet (down 24%, P < 0.01) and with 2,000 ppm curcumin, the effect being particularly evident with large ACFs. The concentration of zerumbone in the Z. aromaticum extract diet was assayed at 300 ppm and of curcumin in the C. longa extract diet was also 300 ppm, i.e., the extract of C. longa was as effective at one-seventh the concentration of curcumin as the positive control. Zerumbone is effective as an anticancer agent, possibly by its apoptosis-inducing and antiproliferative influences. This latter possibility is currently being investigated.

Determination of oak lactones in barrel-aged wines and in oak extracts by stable isotope dilution analysis

The cis- and trans-isomers of 5-butyl-4-methyl-4,5-dihydro-2(3H)-furanone, the so-called oak lactones, are derived from oakwood, and the cis-isomer is an important contributor to wine flavour. Their deuterium-labelled forms, [2H4]cis-oak lactone and [2H4]trans-oak lactone, were synthesised from the unlabelled analogues, and were utilised in a new method employing gas chromatography-mass spectrometry to determine the concentration of these compounds in wine or extracts of oak shavings in a single analysis. The method can employ either liquid-liquid extraction or solid-phase microextraction, and is both rapid and accurate. There was some artefactual generation of cis-oak lactone during the analysis of model wine extracts of unheated oak shavings when diethyl ether extraction and injector block temperatures at or above 225 degrees C were employed.

Rationalization of the effects of compatible solutes on protein stability in terms of thermodynamic nonideality

Inhibition by compatible solutes such as proline and glycine betaine of the rate of coagulation, at 60 degrees C, of bovine serum albumin in 0.1 M acetate buffer, pH 5, is used as a model system to substantiate the concept that the production of high concentrations of osmolytes by plants and other organisms in response to stress (e.g., drought) results in stabilization of native enzyme structures via nonspecific excluded volume effects. The paradoxical situation whereby this effect of compatible solutes counters to some extent the protein-precipitating effect of poly(ethylene glycol) is also seemingly resolved.

Phytic acid in pollen

Abstract Phytic acid has been identified by paper electrophoresis and NMR spectroscopy in extracts of pollen from Petunia hybrida . In this species pollen wa

Charge equilibria and pKa of malvidin-3-glucoside by electrophoresis

Paper electrophoresis has been used over the pH range 1.2 to 10.4 to measure apparent pK(a) values for malvidin-3-O-glucoside of pK(a(1)) 1.76+/-0.07, pK(a(2)) 5.36+/-0.04, and pK(a(3)) 8.39+/-0.07. Using solvent partitioning between buffered aqueous solutions and n-octanol, several micro-pK(a) constants for malvidin-3-O-glucoside were also identified, highlighting the complex nature of malvidin-3-glucoside equilibria. As a nonspectrophotometric procedure, the charge-dependent electrophoretic mobility method provided independent information on the net charge and color of anthocyanin species at wine pH (ca. 3.6). At this pH, the color of malvidin-3-glucoside in red wines is consistent only with the uncharged quinonoidal base as a major colored component of the equilibria.

Screening for Antitumor Activity of 11 Species of Indonesian Zingiberaceae Using Human MCF-7 and HT-29 Cancer Cells

We have screened 11 important species of Zingiberaceae, used as spices and for medicinal purposes in Indonesia, for their antitumor activity using human HT-29 colon cancer and MCF-7 breast cancer cells. They were Amommum cardamomum, Curcuma aeruginosa, C. longa, C. mangga, C. xanthorrhiza, Kaempferia galanga, K. pandurata, K. rotunda, Z. aromaticum, Z. cassumunar, and Zingiber officinale. Ethanol extracts of eight species showed strong inhibitory effect on the growth of the cancer cells when evaluated using the colorimetric tetrazolium salt assay. Since curcumin, a yellow pigment isolated from C. longa, has shown its potential anticancer activity in vitro and in vivo studies and is currently undergone clinical trial in the US, we used an extract of C. longa as a comparison. Extracts of K. pandurata and Z. aromaticum had very strong inhibitory activity against the two cell lines similar to those of C. longa. However, curcumin was not detectable in the extracts of those two plants. The ethanol extracts of the active species had less effect on the growth of a non-transformed human skin fibroblast cell line (SF 3169). Microscopic examination of cancer cells exposed to extracts of active species showed a characteristic morphology of apoptosis. Further study on Z. aromaticum and K. pandurata, including identification of bioactive compounds and elucidation of mechanism(s) likely to be operating, has been carried out.

Accumulation of proline analogues and adaptation of Melaleuca species to diverse environments in Australia

The genus Melaleuca is native to Australia, with about 250 species spread from favourable to very stressful ecological habitats. We analysed the leaves of 125 Melaleuca species for the accumulation of proline analogues to explore relationships between the ability of the species to accumulate proline analogues and their ability to adapt to various stressful habitats in Australia. Melaleuca species that have evolved the ability to accumulate only L-proline seem to be adapted to non-saline or non-sodic soils in regions of higher rainfall. Species that accumulate N-methyl-L-proline seem to be adapted to saline and/or sodic soils with moderate amount of rainfall. Species that accumulate trans-4-hydroxy-N-methyl-L-proline seem to be adapted to saline and/or sodic soils and occur in areas with considerably lower rainfall, while species that accumulate trans-4-hydroxy-N,N-dimethyl-L-proline are widely distributed in Australia, with a particular adaptation to extremely arid (deserts) and saline and/or sodic soils. The species accumulating more than one osmoprotectant seem to have an ecophysiological advantage over plants accumulating only one osmoprotectant.

Nitrogenous compatible solutes in drought-stressed Medicago spp.

Abstract Seven annual Medicago spp. (subgenus Spirocarpos) were examined for their content of nitrogenous compatible solutes under drought stress. All contained proline and glycine betaine. Five contained stachydrine and/or trigonelline while none had homostachydrine. The perennial, M. sativa (subgenus Medicago), contained proline, stachydrine, homostachydrine and trigonelline, while no glycine betaine was found.

The polarograph1c estimation of molybdenum in plant materials

Abstract A method has been developed whereby molybdenum is extracted from digests of plant materials by means of a-benzomoxime and chloroform from a medium of 1 % sulphuric acid solution, Following the decomposition of the extract, the molybdenum is estimated polarographically by measuring the catalytic wave in a sulphuric acid-pcrchloratc supporting electrolyte in which the sensitivity is increased tenfold over the normal wave. The method provides a selective, highly sensitive procedure, capable of determining very small quantities of molybdenum.