Anna Stojakowska

Arbuscular mycorrhizal fungi alter thymol derivative contents of Inula ensifolia L.

Individuals of Inula ensifolia L. (Asteraceae), a valuable xerothermic plant species with potential therapeutic value, were inoculated under laboratory conditions with different strains of arbuscular mycorrhizal fungi (AMF): (1) Glomus intraradices UNIJAG PL-Bot, (2) G. intraradices UNIJAG PL-Kap, (3) Glomus clarum UNIJAG PL13-2, and (4) AMF crude inoculum from natural stands of I. ensifolia. We found AMF species specificity in the stimulation of thymol derivative production in the roots of I. ensifolia. There was an increase in thymol derivative contents in roots after G. clarum inoculation and at the same time the decreased production of these metabolites in the G. intraradices treatments. Moreover, no correlation between the extent of AMF colonization and the effects of the fungal symbionts on the plant was observed. A multilevel analysis of chlorophyll a fluorescence transients (JIP test) permitted an evaluation of plant vitality, expressed in photosynthetic performance index, influenced by the applied AMF strains, which was found to be in good agreement with the results concerning thymol derivative production. The mechanisms by which AMF trigger changes in phytochemical concentration in plant tissues and their consequences for practice are discussed.

Mycorrhizal fungi modulate phytochemical production and antioxidant activity of Cichorium intybus L. (Asteraceae) under metal toxicity.

Cichorium intybus (common chicory), a perennial plant, common in anthropogenic sites, has been the object of a multitude of studies in recent years due to its high content of antioxidants utilized in pharmacy and food industry. Here, the role of arbuscular mycorrhizal fungi (AMF) in the biosynthesis of plant secondary metabolites and the activity of enzymatic antioxidants under toxic metal stress was studied. Plants inoculated with Rhizophagus irregularis and non-inoculated were grown on non-polluted and toxic metal enriched substrata. The results presented here indicate that AMF improves chicory fitness. Fresh and dry weight was found to be severely affected by the fungi and heavy metals. The concentration of hydroxycinnamates was increased in the shoots of mycorrhizal plants cultivated on non-polluted substrata, but no differences were found in plants cultivated on metal enriched substrata. The activity of SOD and H2O2 removing enzymes CAT and POX was elevated in the shoots of mycorrhizal plants regardless of the cultivation environment. Photochemical efficiency of inoculated chicory was significantly improved. Our results indicate that R. irregularis inoculation had a beneficial role in sustaining the plants ability to cope with the deleterious effects of metal toxicity.

Flavonoid production in transformed root cultures of Scutellaria baicalensis.

Summary Agrobacterium rhizogenes LBA 9402 transformed root cultures of Scutellaria baicalensis Georgi (Lamiaceae) were established and examined in respect to their capability to produce flavonoids characteristic of roots of the intact plant. The flavonoids were quantified by RP-HPLC after previous acid hydrolysis of glycosides to the corresponding aglycones. An effect of a nutrient medium composition on growth and flavonoid content in the cultures was studied. Optimum for flavonoid production was half-strength Gamborg B5 medium containing 5-7% sucrose. Roots grown in the medium yielded up to 7% dry weight of baicalein, 1.9 % dry weight of wogonin and 1.3 % dry weight of oroxylin A.

Sesquiterpene lactones in a hairy root culture of Cichorium intybus.

A transformed root culture of Cichorium intybus L. (Asteraceae) was found to produce sesquiterpene lactones of guaiane and germacrane type. Lactucopicrin, 8-desoxylactucin and three sesquiterpene lactone glycosides: crepidiaside B, sonchuside A and ixerisoside D were isolated from the roots. The yield of 8-desoxylactucin reached 0.03 g l-1 at the early stationary phase of the culture.

Caffeic acid derivatives from a hairy root culture of Lactuca virosa

In a search for biologically active phenolics, a hydroalcoholic extract from the hairy roots of Lactuca virosa was fractionated by chromatographical methods. The procedure led to the isolation of a substantial amount of 3,5-dicaffeoylquinic acid (3,5-DCQA)—a potent free radical scavenger. An analytical RP-HPLC separation of the hydroalcoholic extract from the hairy roots allowed identification of further hydroxycinnamates: caftaric acid (CTA), chlorogenic acid (5-CQA) and cichoric acid (DCTA), as well as small amounts of unbound phenolic acids. A time course of growth and caffeic acid derivatives accumulation in the hairy root culture was also investigated. The highest contents of the compounds in the examined roots were detected at the logarithmic phase of growth. The average content of 3,5-DCQA in the roots (ca. 2.5% DW) was at least one order of magnitude higher than that found in roots of Lactuca species and callus culture of L. virosa.

Sesquiterpene lactones in Agrobacterium rhizogenes—Transformed hairy root culture of Lactuca virosa

Investigation of hairy root culture of Lactuca virosa transformed with Agrobacterium rhizogenes resulted in the isolation of eight sesquiterpene lactones, six of which were glycoside derivatives. In addition, stigmasterol together with known triterpenes and their acetates were found. The compounds were identified by spectroscopic methods.

Salicylate and methyl jasmonate differentially influence diacetylene accumulation pattern in transformed roots of feverfew

In hairy root cultures of feverfew (Tanacetum parthenium (L.) Sch. Bip.), treated with methyl jasmonate (MJ), accumulation of spiroketal enol ether type diacetylenes of known deterrent activity was increased about two-fold. The phenomenon was independent of the root clone studied. The maximum total acetylene content (≈2.5 and 1.1% dry weight in clones M2 and I2, respectively) was observed after 72–96 h MJ treatment. Salicylic acid (SA) transiently reduced a content of constitutive spiroketal enol ethers, common for all root clones, but selectively enhanced accumulation of cis-C13-spiroketal enol ether epoxide ((E)-3,4-epoxy-2-(2,4-hexadiynylidene)-1,6-dioxaspiro[4.4]nonane) (2), present in clone M2. Simultaneous addition of SA and MJ to the culture medium influenced diacetylene spectrum in a salicylate-like manner, but accumulation of the epoxide in clone M2 was more abundant (up to 6-fold increase compared with the control).

A sesquiterpene coumarin ether from transformed roots of Tanacetum parthenium

The roots of Tanacetum parthenium transformed with Agrobacterium rhizogenes afforded, in addition to the known coumarin isofraxidin, a new isofraxidin drimenyl ether which was characterized as 9-epipectachol B by spectral methods.

Root tubers of Lactuca tuberosa as a source of antioxidant phenolic compounds and new furofuran lignans.

From the root tubers of Lactuca tuberosa, a wild edible plant species, nine phenolic compounds were isolated, including two new furofuran lignan glucosides, named lactuberin A and lactuberin B. Their structures were elucidated by spectroscopic methods, especially HRESIMS and 2D NMR techniques. This is the first time that compounds belonging to the epi series of 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane type furofuran lignans have been found in Lactuca species. The total phenolic content of the root tuber extract was evaluated and its major phenolic constituents, caffeic acid, chlorogenic acid and 3,5 dicaffeoylquinic acid, known to possess antioxidant activity, were quantified. Additionally, the root tuber extract showed DPPH radical scavenging activity implying its potential as functional food.

Production of parthenolide in organ cultures of feverfew

In vitro culture ofTanacetum parthenium (L.) Sch.Bip. was initiated from aseptically germinated seedlings. culture was derived from nodal explants of the seedlings on MS medium containing 4.44 μM (1.0 mg 1−1 ) 6-benzylaminopurine (BA) and 0.54 μM (0.1 mg 1−1) of α-naphthaleneacetic acid (NAA). Transformed roots were obtained by infection of the stems of aseptically grown seedlings withAgrobacterium rhizogenes LBA 9402. The parthenolide content in the cultivated plant organs was investigated by RP-HPLC. The production of the compound was strongly influenced by the genotype of the parent plant and ranged from 0.13% to 0.75% dry weight in the shoots of the rooted plantlets grownin vitro. The yield of the compound in multiple shoot cultures ofT.parthenium reached 60% of that found in the shoots of rooted plantlets. In contrast to shoots, only trace amounts of parthenolide could be detected in some clones of transformed roots and the roots of plantlets.