Browsing by Subject "Rhazya stricta"

Sort by: Order: Results:

Now showing items 1-3 of 3
  • Akhgari , Amir; Laakso, Into; Seppänen-Laakso, Tuulikki; Yrjönen, Teijo; Vuorela, Heikki; Oksman-Caldentey, Kirsi-Marja; Rischer, Heiko (2015)
    Rhazya stricta Decne. (Apocynaceae) contains a large number of terpenoid indole alkaloids (TIAs). This study focused on the composition of alkaloids obtained from transformed hairy root cultures of R. stricta employing ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). In the UPLC-MS analyses, a total of 20 TIAs were identified from crude extracts. Eburenine and vincanine were the main alkaloids followed by polar glucoalkaloids, strictosidine lactam and strictosidine. Secodine-type alkaloids, tetrahydrosecodinol, tetrahydro- and dihydrosecodine were detected too. The occurrence of tetrahydrosecodinol was confirmed for the first time for R. stricta. Furthermore, two isomers of yohimbine, serpentine and vallesiachotamine were identified. The study shows that a characteristic pattern of biosynthetically related TIAs can be monitored in Rhazya hairy root crude extract by this chromatographic method.
  • Nykänen, Tina (Helsingfors universitet, 2013)
    Rhazya stricta Decne. is a small evergreen shrub belonging to the Apocynaceae family. The plant grows in South Asia and the Middle East, and in these areas it is used in traditional medicine. All parts of the plant are used in different preparations for a variety of purposes such as infections, bowel diseases, itching and diabetes. R. stricta synthesizes about a hundred different alkaloids, of which only a fraction has been studied closer. Some of the analyzed alkaloids have showed some interesting pharmacological properties such as antibacterial and cytotoxic properties. Because it is often both economically and ecologically unsustainable to cultivate or to collect large amounts of medicinal plants from nature, cell cultures have been developed from plants. The properties and synthesized substances of the cell cultures can be analysed and modified in laboratories. In the experimental part of this work, a system was developed for alkaloid extraction, fractionation and isolation from dried cell material from cultured R. stricta hairy root-cells. The goal was to develop a functioning system that eventually enables identification of the alkaloids synthesized by the cultured cells under given conditions. Alkaloids were extracted from 26 g of dried and ground cell mass. The fractionation of the alkaloids was performed with medium pressure liquid chromatography (MPLC) and the fractions were analyzed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The alkaloids were purified by horizontal TLC and preparative HPLC. Ion-pair chromatography was used for analyzing the extract, fractions and purified alkaloids. Five components from two fractions were eventually isolated. One of the components was tentatively identified as vincanine, but further analyzes have to be performed to identify all components reliably. In total, hairy root-cells seem to synthesize approximately 20 alkaloids with variable polarity.
  • Akhgari, Amir; Laakso, Into; Maaheimo, Hannu; Choi, Young Hae; Seppänen-Laakso, Tuulikki; Oksman-Caldentey, Kirsi-Marja; Rischer, Heiko (2019)
    Methyl jasmonate is capable of initiating or improving the biosynthesis of secondary metabolites in plants and therefore has opened up a concept for the biosynthesis of valuable constituents. In this study, the effect of different doses of methyl jasmonate (MeJA) elicitation on the accumulation of terpenoid indole alkaloids (TIAs) in the hairy root cultures of the medicinal plant, Rhazya stricta throughout a time course (one-seven days) was investigated. Gas chromatography-mass spectrometry (GC-MS) analyses were carried out for targeted ten major non-polar alkaloids. Furthermore, overall alterations in metabolite contents in elicited and control cultures were investigated applying proton nuclear magnetic resonance (H-1 NMR) spectroscopy. Methyl jasmonate caused dosage- and time course-dependent significant rise in the accumulation of TIAs as determined by GC-MS. The contents of seven alkaloids including eburenine, quebrachamine, fluorocarpamine, pleiocarpamine, tubotaiwine, tetrahydroalstonine, and ajmalicine increased compared to non-elicited cultures. However, MeJA-elicitation did not induce the accumulation of vincanine, yohimbine (isomer II), and vallesiachotamine. Furthermore, principal component analysis (PCA) of H-1 NMR metabolic profiles revealed a discrimination between elicited hairy roots and control cultures with significant increase in total vindoline-type alkaloid content and elevated levels of organic and amino acids. In addition, elicited and control samples had different sugar and fatty acid profiles, suggesting that MeJA also influences the primary metabolism of R. stricta hairy roots. It is evident that methyl jasmonate is applicable for elevating alkaloid accumulation in "hairy root" organ cultures of R. strica.