Dijana Krstić-Milošević

Phytochemical re-investigation of Gentiana utriculosa

Xanthone-O-glycosides with 1,3,7,8-oxidation pattern and flavone isoorientin-3′-O-glucoside were isolated from the aerial parts of Gentiana utriculosa. Xanthone-C-glucoside lancerin was detected in Gentiana species for the first time. The distribution of these compounds within the section Calathianae is discussed.

Use of Chenopodium murale L. transgenic hairy root in vitro culture system as a new tool for allelopathic assays

We investigated Chenopodium murale transgenic hairy root in vitro culture system as a new tool for allelopathic assays. Transgenic hairy roots were induced by Agrobacterium rhizogenes A4M70GUS from roots, cotyledons, leaves, and internodes of C. murale seedlings. Roots were found to be the best target explants, providing transformation efficiency of up to 11.1%. Established hairy root clones differed in their morphology and growth potential. Molecular characterization of these clones was carried out by PCR, RT-PCR and histochemical GUS analyses. No differences in rol gene expression were observed. Liquid culture system of characterized hairy root clones was maintained for over 2 years. Six hairy root clones were selected for assaying the allelopathic effect of their growth medium against germination and seedling elongation of wheat and lettuce test plants. The inhibitory potential varied depending on the hairy root clone. Some transgenic clones showed significantly higher inhibition compared to wild-type roots. These results revealed that hairy roots as an independent system synthesize some bioactive substances with allelopathic activity and exude them into the growth medium. Concentrations of caffeic, ferulic and p-coumaric acids (0.07-2.85 μmol/L) identified by HPLC analysis in the growth media were at least 1000 times lower than the inhibitory active concentration (5 mmol/L) of pure grade phenolic acids, suggesting that they have a limited role in the allelopathic phenomena of C. murale. The presented hairy root system appears to be a suitable tool for further investigation of the potential and nature of root-mediated allelopathic interference of C. murale.

Somatic embryogenesis and in vitro shoot propagation of Gentiana utriculosa

Abstract Study describes protocols for in vitro propagation of Gentiana utriculosa L. via axillary shoot multiplication and indirect somatic embryogenesis. Shoot cultures were established from seedling epicotyl explants cultured on MS medium supplemented with 0.25 mg L−1 BA and 0.1 mg L−1 IAA. Medium containing 2% sucrose and 0.2 mg L−1 BA improved multiple shoot production, providing 2.3 shoots per explant. The highest rooting (29.6%) was obtained on medium with 1/2 MS mineral salts and 0.5 mg L−1 NAA. Somatic embryogenesis was induced using different explants, including immature seeds as well as leaves and roots from shoot cultures. Following auxin treatment with either 1.0 mg L−1 2,4-D (immature seeds and leaves) or 0.1 mg L−1 NAA (roots), explants produced embryogenic calli which upon transfer to plant growth regulator-free medium allowed embryo conversion into plantlets. The best embryogenic response (82%) was obtained in calli derived from leaves cultured with their abaxial surface in contact with medium, whereas the highest embryo conversion rate (68%) was recorded for calli induced on immature seed explants. Histological analysis in all explant types revealed development of proembryogenic cell complexes at callus periphery, giving rise to somatic embryos. The presence of embryos at various stages of development indicated asynchronous somatic embryogenesis in G. utriculosa. Derooted embryo-derived plantlets placed on medium with 0.2 mg L−1 BA multiplied further as shoot cultures.

Genetic predictors of celiac disease, lactose intolerance, and vitamin D function and presence of peptide morphins in urine of children with neurodevelopmental disorders

Gastrointestinal disturbances, nutritional deficiencies, and food intolerances are frequently observed in children with neurodevelopmental disorders (NDD). To reveal possible association of celiac disease risk variants (HLA-DQ), lactose intolerance associated variant (LCT-13910C>T) as well as variant associated with vitamin D function (VDR FokI) with NDD, polymerase chain reaction-based methodology was used. Additionally, intestinal peptide permeability was estimated in NDD patients and healthy children by measuring the level of peptides in urine using high-performance liquid chromatography. Levels of opioid peptides, casomorphin 8, and gluten exorphin C were significantly elevated in urine samples of NDD patients (P = 0.004 and P = 0.005, respectively), but no association of genetic risk variants for celiac disease and lactose intolerance with NDD was found. Our results indicate that increased intestinal peptide permeability observed in analyzed NDD patients is not associated with genetic predictors of celiac disease or lactose intolerance. We have also found that FF genotype of VDR FokI and lower serum levels of vitamin D (25-OH) showed association with childhood autism (CHA), a subgroup of NDD. We hypothesize that vitamin D might be important for the development of CHA.

Xanthone-rich extract from Gentiana dinarica transformed roots and its active component norswertianin induce autophagy and ROS-dependent differentiation of human glioblastoma cell line

BACKGROUND Glioblastoma multiforme (GMB) is the most malignant of all brain tumors with poor prognosis. Anticancer potential of xanthones, bioactive compounds found in Gentiana dinarica, is well-documented. Transformation of G. dinarica roots with Agrobacterium rhizogenes provides higher xanthones accumulation, which enables better exploitation of these anticancer compounds. HYPOTHESIS/PURPOSE The aim of this study was to investigate antiglioma effect of three different G. dinarica extracts: E1-derived from untransformed roots, E2-derived from roots transformed using A. rhizogenes strain A4M70GUS, and E3-derived from roots transformed using A. rhizogenes strain 15834/PI. Further, mechanisms involved in anticancer potential of the most potent extract were examined in detail, and its active component was determined. METHODS The cell viability was assessed using MTT and crystal violet test. Cell cycle analysis, the expression of differentiation markers, the levels of autophagy, and oxidative stress were analyzed by flow cytometry. Autophagy and related signaling pathways were assessed by immunoblotting. RESULTS E3, in contrast to E1 and E2, strongly reduced growth of U251 human glioblastoma cells, triggered cell cycle arrest in G2/M phase, changed cellular morphology, and increased expression of markers of differentiated astrocytes (glial fibrillary acidic protein) and neurons (β-tubulin). E3 stimulated autophagy, as demonstrated by enhanced intracellular acidification, increased microtubule-associated light chain 3B (LC3-I) conversion to autophagosome associated LC3-II, and decreased level of selective autophagy target p62. Induction of autophagy was associated with Akt-dependent inhibition of main autophagy suppressor mammalian target of rapamycin (mTOR). Both genetic and pharmacological inhibition of autophagy suppressed the expression of differentiation markers, but had no effect on cell cycle arrest in E3-treated cells. E3 stimulated oxidative stress, and antioxidants vitamin E and N-acetyl cysteine inhibited autophagy and differentiation of E3-treated U251 cells. The most prevalent compound of E3, xanthone aglycone norswertianin, also arrested glioblastoma cell proliferation in G2/M phase and induced glioblastoma cell differentiation through induction of autophagy and oxidative stress. CONCLUSION These results indicate that E3 and its main active component norswertianin may serve as a potential candidate for differentiation therapy of glioblastoma.

Sorbus aucuparia and Sorbus aria as a Source of Antioxidant Phenolics, Tocopherols, and Pigments.

Due to its nutritive and medicinal properties, berries of some Sorbus species are used for the preparation of jams and jelly as well as in traditional medicine. On the other hand, their chemical composition is not much studied especially of those grown in Balkan Peninsula. We have analyzed individual phenolics, tocopherols, carotenoids and chlorophylls using HPLC in berries from Sorbus aucuparia and Sorbus aria collected in different localities in Serbia and Montenegro together with the amounts of total phenolics and proanthocyanidins as well as their radical scavenging activity against DPPH radical. Berries of S. aucuparia were richer source of polyphenolics in comparision with S. aria and, regardless the species and locality, caffeoylquinic acids such as neochlorogenic and chlorogenic acid were the most abundant compounds. Among analyzed tocopherols the most abundant in all samples was α‐tocopherol (0.48 – 19.85 μg/g dw) as it was β‐carotene among carotenoids (mean concentration of 0.98 μg/g dw in S. aucuparia and 0.40 μg/g dw in S. aria, respectively). Correlation between total phenolics and DPPH radical scavenging activity was noticed. Our study represents comprehensive report on chemical composition of S. aucuparia and S. aria which could contribute to a better understanding of their quality.

Biotechnology and Phytochemistry of Gentianella Species from the Central Regions of the Balkan Peninsula

In the central regions of the Balkan Peninsula, the genus Gentianella is represented by six species. Five of them G. albanica , G. austriaca , G. bulgarica , G. ciliata , and G. crispata were subject of phytochemical and in vitro studies. Two species, G. austriaca and G. bulgarica, were established as shoot cultures and procedures developed for their in vitro propagation. Difficulties with seed germination and precocious flowering affected the final propagation stages. Phytochemical analyses were performed on five species from nature and on cultured shoots . Plant material was rich in secondary metabolites with xanthones, flavone-C-glucosides, and secoiridoids as the principal constituents. The xanthone aglycones, demethybellidifolin, bellidifolin, corymbiferin, and their corresponding glucosides were dominant components in all the species investigated. The predominant substitution pattern of xanthones found in the genus Gentianella was 1,3,5,8 and to a lesser extent, 1,3,7,8. Lanceoside and veratriloside were new compounds found in European Gentianella species. In vitro material generally contained less secondary metabolites than plants from nature; the content of secondary products was influenced by the concentration of benzyladenine (BAP) in the culture medium.