Defined or enhanced levels of bioactives
Cheng LQ, Xu YJ, Grotewold E, Jin Z, Wu FY, Fu CX, Zhao D. Characterization of anthocyanidin synthase (ANS) gene and anthocyanidin in rare medicinal plant-Saussurea medusa. Plant Cell Tiss Organ Cult 2007.
Anthocyanidin synthase (ANS, leucoanthocyanidin oxygenase), a 2-oxoglutarate iron-dependent oxygenase, catalyzes the penultimate step in the biosynthesis of the anthocyanin class of flavonoids, from the colorless leucoanthocyanidins to the colored anthocyanidins. Here, we report the cloning and characterization of an anthocyanidin Synthase gene (SmANS1) from a cDNA library derived from a red callus line of Saussurea medusa, a traditional Chinese medicinal plant. SmANS1 exhibits significant similarities in amino acid sequence with members of a family of 2-oxoglutarate-dependent oxygenases. The deduced SmANS1 protein shared 83% and 79% identity with that of Callistephus chinensis and Gerbera hybrids, respectively. Reverse transcription-PCR (RT-PCR) analyses of SmANS1 transcripts showed that the SmANS1 was abundantly expressed in the cell cultures of red cell line and seedlings, and weakly expressed in the counterparts of yellow cell line, but was not expressed in the roots. Further, the anthocyanin composition of cell cultures from Saussurea medusa was investigated using high-performance liquid chromatography/mass spectrometry (HPLC-ESI-MS) and tandem mass spectrometry (MS-MS). Major anthocyanins were identified as 3-O-glucosides cyanidin derivatives and minor peaks were identified as pelargonidin derivatives.
Riedl KM, Lee JH, Renita M, St Martin SK, Schwartz SJ, Vodovotz Y. Isoflavone profiles, phenol content, and antioxidant activity of soybean seeds as influenced by cultivar and growing location in Ohio. J Sci Food Agric 2007.
Isoflavone levels and isoflavone chemical composition in soybeans vary between planting locations although the exact factors which control isoflavone biosynthesis are unclear. We compared levels of 12 isoflavones in soybean seeds of six cultivars grown in four different locations in Ohio in 2002 as determined by high-performance liquid chromatography. Radical scavenging activity was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Total phenolics (TPCs) were determined by using Folin-Ciocalteu reagent. Total isoflavones (TIs) varied five-fold (1573-7710 nmol g(-1)) between seeds from the various location-cultivar combinations. One location (Wooster, Ohio) produced seeds containing half the isoflavones as the other locations tested, apparently due to poor growing conditions. Surprisingly, across the entire data set, with increasing TI the proportion of isoflavones accounted for by the daidzein family increased due primarily to malonyl daidzin. DPPH scavenging did not differ significantly by location or cultivar (P >0.05) and did not correlate with TPC or TI. Profiling soybean isoflavones could help elucidate how isoflavone biosynthesis is regulated and lead to improved disease resistance of soybean crops and soy foods with greater health benefits.
Jin Z, Grotewold E, Qu W, Fu G, Zhao D. Cloning and characterization of a flavanone 3-hydroxylase gene from Saussurea medusa. DNA Seq 2005.
Flavanone 3-hydroxylase (F3H) is a key enzyme in the flavonoid biosynthetic pathway, providing a branching point for the biosynthesis of different flavonoids, including the formation of 3-deoxy and 3-hydroxy flavonoids found in the silks of maize. Here, we report the cloning and characterization of a F3H gene (Smf3h) from a cDNA library derived from a red line callus of Saussurea medusa, a traditional Chinese medicinal plant. The cDNA contains a 1032 bp open reading frame (ORF) encoding a protein of 343 amino acid residues, a 149 bp long 5’untranslated regions (UTR) and a 163 bp long 3’UTR containing three putative polyadenylation signals (AATAAA) and an ATTTA element. The secondary structure of the mRNA predicted by MFOLD is very complex, suggesting a role in a post-transcriptional mechanism of regulation of Smf3h. The genomic structure of Smf3h includes four exons and three introns within the coding region, with all the splice donor/acceptor site sequences in accordance with the “GU-AG” consensus rule. The deduced SmF3H protein is 343 amino acid residues in length and has 40% and 39% identity and 60% and 58% similarity to the F3H of Arabidopsis and rice, respectively. Strikingly, the identity of SmF3H is higher to the H6H (hyoscyamine 3beta-hydroxylase, 45%) from Atropa belladonna. However, the analysis of the active center and the predicted protein secondary structure are more related to F3H than H6H. Together, our studies provide the first identification of a S. medusa flavonoid gene and its similarities to metabolic enzymes from other plants.