THE ISOLATION OF TRITERPEN SAPONINS FROM IRANIAN ASTRAGALUS SPECIES AND THEIR EFFECTS ON IMMUNE SYSTEM
Project no. 1227 · Status: Kapanmış · 2015
Summary
The genus Astragalus, a member of the Fabaceae (Leguminosae) family, comprises the largest genus among the vascular plants with approximately 2000 species in the world. A total of 372 species in North America and 133 species of Astragalus in Europe were identified. Astragalus species are represented by 450 species from which 224 of them have been reported as endemic species in Turkey (Çeçen vd, 2016; Davis, 1970). Apart from this, there are approximately 900 species in the vegetation cover of Iran (Osaloo vd., 2003). Radix Astragali (RA), obtained from the dried roots of some Astragalus species, has been used in traditional medicine due to having some healing effects in animal bites, intoxications, injuries, burns, leukemia and uterine cancer treatments (Çakilcioğlu ve Turkoğlu, 2010; Graf, 1992). Accumulating data suggested that saponins with oleanan and cycloartan skeleton isolated from Astragalus species showed a variety of biological activities such as antiviral (Gariboldi, 1995), immunostimulant (Bedir vd., 2000c; Çalış vd., 1997; Yeşilada vd., 2005; Nalbantsoy vd., 2011), immunostimulants cardiotonic (Khushbaktova vd., 1994), cytotoxic (Radwan vd., 2004), anti-protozoal (Özipek vd., 2005) and wound healing (Sevimli-Gür vd., 2011) effects. Many oleanan and cycloartan type triterpene saponins from Astragalus species were isolated and these compounds were investigated with their immunostimulant, anti-protozoal, anti-cancer, cytotoxic activity as well as their haemolysis effects by our group (Çalış vd., 1997; Bedir vd., 1998, 1999a,1999b; Çalış vd., 1997; Çalış vd., 2008; Denizli vd., 2014; Gülcemal vd., 2011, 2012, 2013; Horo vd., 2010, 2012; Polat vd., 2009, 2010; Savran vd., 2012; Denizli vd., 2014). In vitro and in vivo studies on Astragalus saponins showed that these groups of compounds were significantly able to induce the levels of IL-2 (Nalbantsoy et al., 2012, 2011; Yeşilada et al., 2005). It was also reported that Astragalus extracts were used as immune system-stimulating drugs (Graf, 1992). There are no studies regarding to phytochemical and/or immunomodulatory effects of Iranian Astragalusto date. Therefore, it was aimed to carry out further studies on Astragalus species from Iran / Iran-Turan regions and discover their immunomodulatory activities in the current thesis a few Astragalus species gathered from Iran. In total, 37 compounds were isolated from 3 different Astragalus plants and 4 of these compoundsThe effects of the extracts and some compounds on the immune system were investigated in terms of their effect on the release of immunomodulatory cytokines using human blood and their hemolytic activities against human erythrocytes. Tested extracts and compounds (at doses of 3 2,5g and 6 veg) significantly increased IL-2, IL-17A and INF-? cytokine release, In this study, 22 Iran-Turan Astragalus species were investigated phytochemically by using thin-layer chromatography and 3 Astragalus species (Astragalus brachycalyx FISCHER, Astragalus carjaginii BORISS, Astragalus leiophyllus FREYN & BORNM), which were rich in saponins, were chosen for the current study and NMR was performed using ESI-MS and HR-MS. In total, 37 molecules were isolated from 3 different Astragalus plants of which 4 mollecules were found to be newly identified (3-O-ß-D-xylopyranosyl-6-O-ß-D-glucopyranosyl-16-O-ß-D-glucopyranosyl-3ß, 6?, 16ß , 24 (S), 25-pentahydroxycycloartane, 3-O- [?-L-arabinopyranosyl- (1 › 2) -ß-D-xylopyranosyl] -6-O-ß-D-glucopyranosyl-16-O-ß- Dglucopyranosyl-3ß, 6?, 16ß, 24 (S), 25-pentahydroxycycloartane, 6?, 16ß, 24 (S), 25-tetrahydroxy-cycloartan-3-one and 6-O-ß-D-xylopyranosyl-3ß, 6?, 16ß, 24 (S), 25-pentahydroxycycloartane). The effects of the extracts and some molecules on the immune system were investigated in terms of their effect on the release of immunomodulatory cytokines using human blood and their hemolytic activities against human erythrocytes.