Production of Sesquiterpene-Type Phytoalexins by Hairy Roots of Hyoscyamus albus Co-treated with Cupper Sulfate and Methyl Jasmonate

Abstract

The gram-negative bacteria Agrobacterium rhizogenes is a plant pathogen. On infecting plants it induces adventitious roots, known as "hairy roots." Hairy roots have an excellent growth capacity in simple culture systems without requiring the addition of any exogenous plant hormones.1,2) Furthermore, hairy roots are known to produce secondary metabolites at a high yield compared to those of undifferentiated plant cell suspensions and their mother plants. So, hairy roots were expected to provide a culture system for the production of pharmacologically important natural products and the biotransformation of organic compounds into useful biologically active compounds. Thus, many medicinal plants have been transformed to hairy roots, and there have been many related reports on the efficient production of useful natural products 3-7) and biotransformation of organic substances into useful compounds.8-10) Furthermore, hairy roots were expected to become a simple and easy experimental system for the biosynthesis of secondary metabolites such as phytoalexins, and plant gene engineering.11,12) Elicitation of hairy roots on culture with heavy metal ions such as cupper ion, organic chemicals such as jasmonic acid and biological substances such as yeast extract was studied, and found to enhance defense processes in plants and the production of secondary metabolites such as phytoalexins. 13,14) Especially, there were many reports concerning induction by plant hormones, jasmonic acid, and methyl jasmonate (MeJA). In many cases, MeJA enhanced the production of pharmacologically important secondary metabolites such as defense compounds, phytoalexins, [15][16][17] and defence systems in plants. 18) We reported the production of a coumarin-type phytoalexin, umbelliferone, in Pharbitsis nil hairy roots.19) The P. nil hairy roots also showed substrate specific and strong reactivity on the glucosylation of low-molecular-weight phenolic compounds, and strong reactivity on the reduction of a formyl group on the aromatic ring to a hydroxymethyl group. 20,21) Solanaceae, such as Solanum, Hyoscyamus, and Atropa sp., were used as medicinal plants, yielding alkaloids such as nicotine and tropan alkaloids as the main constituents, but they produced sesquiterpene-type phytoalexins, such as lubimine 22) and solavetivone, 23) after treatment with biotic and abiotic elicitors. We reported the production of sesquiterpene-type phytoallexins in Hyoscyamus albus (Solanaceae) hairy roots treated with MeJA,24) and the efficient production of tropane alkaloids in H. niger hairy roots. 25) We also reported the identification of a strongly expressed gene in H. niger hairy roots, related to and enhancing lateral root formation in H. niger hairy roots. 26) We previously found that products from H. albus hairy roots treated with CuSO 4 , MeJA, and co-treatment of CuSO 4 -MeJA showed different production patterns in terms of the TLC profile. So, we attempted to produce sesquiterpene-type phytoallexins in H. albus hairy roots cell culture by co-treatment with...

Spirovetivane- and Eudesmane-Type Sesquiterpenoids Isolated from the Culture Media of Two Cyanobacterial Strains

“…In terms of variation, from Figure stereoisomer 1 HC­(3β,4α), , stereoisomer 1 HC­(3α,4β), ,,, stereoisomer 3 HC­(3β,4α), ,,, and stereoisomer 4 HC­(3β,4α) have been reported for compounds of this type. Stereoisomer 4 HC­(3α,4β) was only reported as part of a synthesis of (+)-β-vetivone, and there were no reports of stereoisomer 2 from the literature reviewed.…”

“…The conformations are designated HC(3β,4α) or HC(3α,4β), depending on whether C-3 or C-4 is above or below the plane of the alkene, with C-14 equatorial or axial. In terms of variation, from Figure 2 stereoisomer 1 HC(3β,4α), 6,9 stereoisomer 1 HC(3α,4β), 6,7,10,12 stereoisomer 3 HC(3β,4α), 7,8,11,14 and stereoisomer 4 HC(3β,4α) 13 have been reported for compounds of this type. Stereoisomer 4 HC(3α,4β) was only reported as part of a synthesis of (+)-βvetivone, 8 and there were no reports of stereoisomer 2 from the literature reviewed.…”

“…At this point, when we attempted to assign the configuration of 1 by comparing its spectroscopic data with that of known compounds, the considerable configurational variation within this family of spirovetivane-type compounds − and the challenges in assigning the configuration became evident. As shown in the top half of Figure , there are four possible C-4/C-5 stereoisomers, each with two possible half-chair conformations to consider for the carbon core of the spirovetivane-type system.…”

“…Spironostoic acid ( 1 ), 11,12-didehydrospironostoic acid ( 2 ), and 12-hydroxy-2-oxo-11- epi -hinesol ( 4 ) are spirovetivane-type compounds, while stigolone ( 5 ), 11 R ,12-dihydroxystigolone ( 6 ), and 11 S ,12-dihydroxystigolone ( 7 ) are three eudesmane-type compounds primarily isolated from fungi. Interestingly, the literature shows considerable configurational variation in the structure of spirovetivane-type compounds, − so in order to evaluate the variation in these deceptively simple molecules, we developed the following comprehensive approach based on analogous compounds and previous work in the literature while ignoring the isopropyl/isopropenyl tail for simplicity.…”

Hairy Roots, their Multiple Applications and Recent Patents

“…It is noteworthy that sometimes, through elicitation, HR cultures have produced compounds which were absent in the native plant [44]. For instance, phytochemical profile from Hyoscyamus albus HRs changed in response to copper sulphate and methyl jasmonate used as elicitors, and four new sesquiterpene phytoalexins were identified and characterized [45]. Electric current is being used as a clean elicitor and multiple electroelicitation can be applied to enhance phytochemical produc-tion [46].…”