Relationships between the genetic distance of Epichloë festucae isolates and the ergovaline and peramine contents of their Festuca rubra hosts

In semiarid grasslands of western Spain, plants of Festuca rubra are frequently infected by Epichloë festucae , an endophyte capable of producing the alkaloids ergovaline, toxic to mammals, and peramine, toxic to insects. The objectives of this paper were to estimate the variability in the content of ergovaline and peramine in plants of Festuca rubra from natural populations and to determine the relationship between the genetic distance among Epichloë strains and the alkaloid contents of plants infected by them. The results showed that a significant variation exits in the ergovaline and peramine contents of infected F. rubra plants, and that variation patterns are different for each alkaloid. Ergovaline content showed a significant variation between years. In contrast, most variation observed in the concentration of peramine occurred between populations. Mantel tests, constrained correspondence analysis (CCA) and generalised analysis of molecular variance (GAMOVA) all revealed a significant relationship between the genetic distances among 35 Epichloë isolates, and the differences in peramine content of their host plants. The relationship observed for ergovaline was more ambiguous. This indicates that plants infected by genetically close isolates of Epichloë festucae tend to be similar in terms of peramine content, while the ergovaline content of infected plants seems to be more dependent on external factors. The results of this study suggest that the selection of Epichloë festucae endophytes based on the alkaloid content of their host plants can be a successful strategy to select good or bad producers of peramine, but may not be a reliable method to detect fungal strains associated with particular ergovaline production profiles.     

A new dimeric carbazole alkaloid from Murraya koenigii (L.) leaves with α-amylase and α-glucosidase inhibitory activities

A new dimeric carbazole alkaloid, 3,3′,5,5′,8-pentamethyl-3,3′-bis(4-methylpent-3-en-1-yl)-3,3′,11,11′-tetrahydro-10,10′-bipyrano[3,2-a]carbazole, was isolated from the hexane extract of leaves of Murraya koenigii (L.) Sprengel. (Family: Rutaceae). The structure was elucidated based on ¹³C and ¹H NMR, High-Resolution Mass Spectrometry (HRMS), and 2D NMR data. The in vitro antidiabetic activity of the new dimer was investigated in terms of α-amylase and α-glucosidase enzyme inhibition assays. The dimer exhibited significant α-amylase inhibitory activity (IC₅₀ = 30.32 ± 0.34 ppm) and α-glucosidase inhibitory activity (IC₅₀ = 30.91 ± 0.36 ppm).     

17-O-acetyl-19,20-dihydrovoachalotine,a new alkaloid from Voacanga chalotiana

The structure of 17-O-acetyl-19,20-dihydrovoachalotine, a new alkaloid from the root bark of Voacanga chalotiana, has been determined by spectroscopic analysis. The stereochemistry at C-20 has been deduced on the basis of ¹³C-NMR and comparison with other compounds containing the voachalotine skeleton.     

A nuclear magnetic resonance study of the diastereoisomer complexes formed between a terguride derivative and naproxen

¹H NMR (600 MHz) measurements of chemical shift changes were made in acidified (DCI) CD₃OD/D₂O 1:9 v/v equimolar solutions of (S)- and (R,S)-6-methoxy-α-methyl-2-naphthaleneacetic acid (naproxen) in the presence of 1-(3-aminopropyl)-(5R,8S,10R)-terguride (AMP-TER). The most significant bonding interactions concurring to the formation of diastereoisomer complexes are seen as chemical shifts in proximity to the positively charged nitrogen N(6)-CH₃ and of H(12), H(13), H(14) protons of the ergoline skeleton, both the adducts having an electrostatic term and different π–π stabilizing interactions. Chemical shift data exclude any contribution of the aminopropyl chain to the chiral recognition mechanism. These findings provide an experimental basis for the enantiodiscriminative process accounting for the observed chromatographic resolutions of arylcarboxylic acids on chiral stationary phases derived from AMP-TER. © 1994 Wiley-Liss, Inc.     

Lupin alkaloids from Sophora mollis

The major alkaloids of Sophora mollis are (+)-sparteine and (?)-cytisine, and the minor ones are also of the sparteine-type (lupanine and 5,6-deh     

5-Methoxy-1-oxo-tetrahydro-β-carboline,an alkaloid from Alstonia venenata

A new oxo-tetrahydro-β-carboline alkaloid has been isolated from the root bark of Alstonia venenata. It was identified as 5-methoxy-1-oxo-tetrahydro-β-carboline.     

The relationship between l-dopa decarboxylase in the latex of Papaver somniferum and alkaloid formation

The presence of l-dopa decarboxylase has been demonstrated in poppy latex utilising l-dopa-1-[¹⁴C] and l-dopa-3-[¹⁴Cl] as substrates. The enzyme appeared to have maximum activity at pH 7.2 and showed both substrate and pyridoxal phosphate inhibition. The substrates l-tyrosine, l-phenylalanine and l-histidine were also decarboxylated. l-dopa decarboxylase was found to occur solely in the latex supernatant fraction. The possible involvement of this enzyme in alkaloid biosynthesis in the latex is discussed.     

Morphine metabolism and normorphine in Papaver somniferum

Normorphine has been established as an active metabolite of morphine in P. somniferum. This was done by, (a) demonstrating the presence of normorphine throughout the life cycle of the plant, (b) finding normorphine-¹⁴C after feeding morphine-¹⁴C via the roots, and (c) exposing opium poppies to ¹⁴CO₂ under steady state conditions which led to morphine and normorphine of the same specific activity. Feeding normorphine-¹⁴C showed that the N-demethylation step is irreversible. A sensitive procedure was developed for the detection of normorphine in the presence of large amounts of morphine; using this procedure, normorphine was found in raw opium. These results indicate that the major, if not the sole, morphine degradative pathway involves an initial demethylation to normorphine, which is subsequently degraded to non-alkaloidal metabolites. The high rates of turnover observed led to the conclusion that the morphine alkaloids do play an active metabolic role, perhaps as specific methylating agents.