Production of rhoifolin and tiliroside from callus cultures of Chorisia chodatii and Chorisia speciosa

The current work aims to stimulate the production of rhoifolin and tiliroside as two valuable phytochemicals from Chorisia chodatii Hassl. and Chorisia speciosa A. St.-Hil. callus cultures. A comparison between three explants from the in vitro germinated seedlings of both species for callus induction and accumulation of both flavonoids was carried out. Highly efficient calluses were induced from the leaves, stems and roots of C. chodatii seedlings on Gamborg’s B5 (B5) and Murashige and Skoog (MS) media containing 2.0 mg/l β-naphthalene acetic acid (NAA) and 0.5 mg/l 6-benzyladenin (BA) or kinetin (Kn), while those of C. speciosa seedlings efficiently produced calluses on both media supplemented with 0.5 or 1.0 mg/l NAA and 0.5 mg/l BA. Besides, the highest contents of rhoifolin (1.927 mg/g DW) and tiliroside (1.776 mg/g DW) from C. speciosa cultures were obtained from the calluses of seedlings’ roots and stems maintained on B5 medium containing 1.0 mg/l NAA and 0.5 mg/l BA, respectively. On the other hand, the maximum rhoifolin content (0.555 mg/g DW) from C. chodatii cultures was obtained from the calluses of seedlings’ stems grown on B5 medium supplemented with 2.0 mg/l NAA and 0.5 mg/l BA, whereas the highest tiliroside content (0.547 mg/g DW) was provided by the root explants on B5 medium containing 2.0 mg/l NAA and 0.5 mg/l Kn. Both flavonoids were bioaccumulated in greater amounts than the wild and cultivated intact plants, which provides a promising tool for their future commercial production under a controlled environment, independent of climate and soil conditions.     

Chemical constituents from Lespedeza cuneata G. Don (Leguminosae)

Phytochemical investigation of Lespedeza cuneata led to the isolation of seventeen compounds including three steroids (β-sitosterol 1, β-sitosterol-6′-linolenoyl-3-O-β-d-glucopyranoside 3, and β-sitosterol glucoside 13), nine flavonoids (quercetin 4, kaempferol 5, isovitexin 8, hirsutrin 9, nicotiflorin 10, vitexin 11, astragalin 12, trifolin 14, and isorhamnetin 17), two phenolics (benzyl-β-d-glucopyranoside 7 and homovanillyl alcohol 16), one carotenoid (loroxanthin 2), one lignin (7R,8S–dihydrodehydrodiconiferyl alcohol 15), and one hexose (pinitol 6) on the basis of their spectroscopic data. Among these compounds, 2, 3, 7, 15 and 16 were reported for the first time from the genus Lespedeza. The taxonomic significance of these isolated compounds was also summarized.     

Chemical constituents from Gentianella turkestanorum (Gentianaceae)

Phytochemical investigation of Gentianella turkestanorum (Gentianaceae) afforded nineteen compounds, including six xanthones (1–6), two triterpenoids (7–8), eight flavones (9–16) and three iridoids (17–19). Here, we firstly reported that 1-hydroxy-3,5-dimethoxyxanthone (4), 1, 8-dihydroxy-3-methoxyxanthone (5), apigenin (9), quercetin (10), luteolin-7-O-glucoside (12) and three other compounds (1, 8-dihydroxy-3-methoxyxanthone (5), apigenin-7-O-gluco (1″ → 3‴) glucoside (15) and luteolin-7-O-gluco (1″ → 3‴) glucoside (16)) could be isolated from G. turkestanorum. The occurrence of chemical data and the sequence data might be employed as common constituents of the genera Gentianella, Lomatogonium and Swertia.     

Interference by luteolin,quercetin, and taxifolin with chloroplast-mediated electron transport and phosphorylation

Summary The effects of luteolin, quercetin, and taxifolin on light induced phosphorylation and electron transport in isolated, greenhouse-grown, spinach (Spinacia oleracea L.) thylakoids were investigated. Luteolin and quercetin interacted with components associated with both the ATP-generating pathway and the electron-transport pathway. However, the action of taxifolin involved only the phosphorylation pathway. Interference with the phosphorylation pathway was evidenced by the greater sensitivity of phosphorylation than oxygen uptake in coupled whole-chain electron transport, inhibition of the light-activated Mg²⁺-ATPase, and inhibition of the Ca²⁺-ATPase associated with CF₁. The following order of decreasing inhibitory effectiveness was exhibited: luteolin > quercetin >>> taxifolin. On the electron-transport pathway, luteolin and quercetin interfered with the activity of the Q_B-protein complex as evidenced by inhibition of the partial reaction with diphenylcarbazide as the electron donor and 2,6-dichlorophenolindophenol as electron acceptor; alteration of the chlorophyll fluorescence transients; and competitive displacement of radiolabeled atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine].     

Trinorguaian and germacradiene type sesquiterpenes along with flavonoids from the herbs of Pimpinella cappadocica Boiss. & Bal.

A trinorguaian-type sesquiterpenoid named kanalpin and two acylated flavonol glycosides named erzurumin and ilicanin have been isolated from Pimpinella cappadocica Boiss. & Bal., together with three known sesquiterpenoids and six known flavonoid glycosides. The structures of these compounds were determined by extensive spectroscopic (UV, IR, EI–MS, APCI–MS, HR-ESI-MS, 1D and 2D NMR) analyses. Antioxidant capacity of isolated secondary metabolites containing extracts of P. cappadocica was evaluated.