Biologically Active Terpenoids fromTamarix Species

Abstract

We carried out research of bioactive substances obtained from ethanol extract (70%). This ethanol extract (70%) was obtained by us from the aerial parts of Tamarix plants (Т.laxa Willd., T.hispida Willd., T.ramosissima Ledeb. and Т.еlongatа Ledeb.). These plants belong to the family of Tamaricaceae which grow on the territory of Kazakhstan. For the preliminary separation of bioactive substances, the fractional extraction of ethanol extracts (70%) of Tamarix species was carried out using chloroform and ethyl acetate. Chloroform and ethyl acetate extracts contained terpenoids (positive reactions with Lieberman-Burchard reagent and cerium sulfate). Isolation of terpenoids from chloroform and ethyl acetate extracts was achieved by a series of separations on chromatography column over silica gel and these terpenoids were eluted with gradient mixture of hexaneethylacetate (0-100%). From the aerial parts of Tamarix (Т.laxa Willd., T.hispida Willd., T.ramosissima Ledeb., Т.еlongatа Ledeb) five terpenoids were isolated. Their structures of 1-5 were found using alkaline hydrolysis and UV, IR, 1H and 13C NMR, COSY-45˚, HMQC, HMBC, EIMS, FABMS (-ve) spectral analyses. Pentacyclic triterpenoids: ursolic acid (1), 3β-al-D- friedoolean-14-en-28-oic acid methyl ether (2), 3-α-[3´´,4´´-dihydroxy-trans-cinnamoyloxy]-D-friedoolean-14-en-28-oic acids (isotamarixen) (3), 3-α-hydroxy-D-friedoolean-14-en-28-oic acid (4) and 3-α-[4´´-dihydroxy-trans-cinnamoyloxy]-Dfriedoolean -14-en-28-oic acid (5) were isolated from the aerial parts of Tamarix. Ethanol extracts (70%), chloroform, ethylacetate extracts from Tamarix laxa, Tamarix elongata showed antioxidant activity. Antioxidant activities were determined using the DPPH (1, 1-diphenyl-2-picrylhydrazyl radical) scavenging method. Ethanol extracts from Tamarix hispida (50%) were found to contain the triterpenoid: 3-α-[3´´,4´´-dihydroxy-trans-cinnamoyloxy]-D-friedoolean-14-en-28-oic acids (isotamarixen), which were tested in vitro for their effect on the α-glycosidase enzyme activity. 3-α-[3´´, 4´´-dihydroxy-trans-cinnamoyloxy]-D-friedoolean-14-en-28-oic showed inhibiting effect on the α-glycosidase enzyme activity and was found to be a potent antioxidant.