Iridoid glucosides in Griselinia, Aralidium and Toricellia

From three of five investigated species of Griselinia a new iridoid glucoside, griselinoside, was isolated. It was found to be present also in foliage of Aralidium pinnatifidum and Toricellia angulata, accompanied in the former by aralidioside another novel iridoid glucoside. The structures and absolute configurations of the two iridoids were elucidated by NMR spectroscopy and chemical conversions. From G. littoralis and T. angulata the glucosides magnolioside and syringoside respectively were isolated. ¹³C NMR spectra are given for thirteen iridoid derivatives.     

Two new iridoid glucosides from Gardenia jasminoides fruits

From the fruits of Gardenia jasminoides which have been employed as Chinese crude drug “Shan-zhii”, two further new iridoid glucosides, gardoside (8,10-dehydrologanic acid) and scandoside methyl ester have been isolated and their structures have been established.     

Two new iridoid glucosides from Mussaenda parviflora and Mussaenda shikokiana

From the leaves of Mussaenda parviflora, two new iridoid glucosides, mussaenoside and shanzhiside methyl ester were isolated and their structures e     

Iridoid glucosides from Satureja Vulgaris

Satureja vulgaris was shown to contain two new iridoid glucosides, 5-deoxylamiol and 4-methylantirrhinoside, as well as the known iridoid glucosides lamiol and 5-deoxylamioside. The structures of the new glucosides were established by spectroscopic studies and chemical evidence.     

The structural elucidation of a novel iridoid derivative from Tachiadenus longiflorus (Gentianaceae) using the LSD programme and quantum chemical computations

Oleanolic acid, scoparone, scopoletin and a novel iridoid derivative, angelone, were isolated from Tachiadenus longiflorus (Gentianaceae). The structure of angelone was determined from NMR data, given as input to the Logic for Structure Determination Programme, and was finally confirmed by comparison of experimental 13C-NMR chemical shifts with those obtained by quantum mechanical calculations.     

DIET QUALITY AFFECTS WARNING COLORATION INDIRECTLY: EXCRETION COSTS IN A GENERALIST HERBIVORE

Aposematic herbivores are under selection pressure from their host plants and predators. Although many aposematic herbivores exploit plant toxins in their own secondary defense, dealing with these harmful compounds might underlay costs. We studied whether the allocation of energy to detoxification and/or sequestration of host plant defense chemicals trades off with warning signal expression. We used a generalist aposematic herbivore Parasemia plantaginis (Arctiidae), whose adults and larvae show extensive phenotypic and genetic variation in coloration. We reared larvae from selection lines for small and large larval warning signals on Plantago lanceolata with either low or high concentration of iridoid glycosides (IGs). Larvae disposed of IGs effectively; their body IG content was low irrespective of their diet. Detoxification was costly as individuals reared on the high IG diet produced fewer offspring. The IG concentration of the diet did not affect larval coloration (no trade-off) but the wings of females were lighter orange (vs. dark red) when reared on the high IG diet. Thus, the difference in plant secondary chemicals did not induce variation in the chemical defense efficacy of aposematic individuals but caused variation in reproductive output and warning signals of females.     

Composition of Soluble Nucleotides in Growing Corms of Amorphophallus konjac C. Koch

The nucleotides and the activities of both sucrose synthetase and granular starch synthetase in the konjak corm (Amorphophallus konjac C. Koch) have been investigated as a preliminary experiment on konjak mannan biosynthesis. On chromatographic separation on anion exchange resin and paper of compounds present in the acid ethanol extract from the corms, ascorbic acid, AMP, ADP, ATP, ADP-glucose, UTP, UDP-glucose, GTP, and GDP-mannose were isolated and tentatively identified. An unidentified nucleotide was also isolated.

Of the three nucleotide sugars, UDP-glucose was the most plentiful, while ADP-glucose was the least. The sucrose synthetase in konjak corms was as active as that in other plants. These observations suggest that the mechanism involved in sucrose cleavage in konjak corms is the same as that in other plants, such as sweet potato roots. Starch synthetase bound to starch granules in konjak corms was also found to be active when ADP-glucose was used as glucose donor. But UDP-glucose could not be substituted for ADP-glucose.

Based on these observations the mechanism of konjak mannan biosynthesis is discussed.     

大孔吸附树脂对栀子中环烯醚萜苷类成分的富集行为

采用大孔吸附树脂对栀子中环烯醚萜苷类成分的富集行为进行研究,结果表明,D101大孔吸附树脂柱层析适合分离纯化栀子中环烯醚萜苷类成分,采用80%乙醇洗脱,紫外-可见分光光度法进行定量测定。使用该方法富集后,80%乙醇洗脱液干燥后总固体物中环烯醚萜苷类成分含量可达到70%以上。