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Abstract Three hitherto undescribed Stemona alkaloids, named stemajapines A–C (1–3), along with six known alkaloids (4–9), were isolated and identified from the roots of Stemona japonica (Blume) Miq. (Stemonaceae). Their structures were established by the analysis of the mass data, NMR spectra, and computational chemistry. Stemjapines A and B were degraded maistemonines without spiro-lactone ring and skeletal methyl from maistemonine. Concurrence of alkaloids 1 and 2 revealed an undescribed way to form diverse Stemona alkaloids. Bioassay results disclosed the anti-inflammatory natural constituents stemjapines A and C with IC50 values of 19.7 and 13.8 µM, respectively, compared to positive control dexamethasone with 11.7 µM. The findings may point out a new direction of Stemona alkaloids inaddition to its traditional antitussive and insecticide activities.

Three hitherto undescribed Stemona alkaloids, named stemajapines A–C (1–3), along with six known alkaloids (4–9), were isolated and identified from the roots of Stemona japonica (Blume) Miq. (Stemonaceae). Their structures were established by the analysis of the mass data, NMR spectra, and computational chemistry. Stemjapines A and B were degraded maistemonines without spiro-lactone ring and skeletal methyl from maistemonine. Concurrence of alkaloids 1 and 2 revealed an undescribed way to form diverse Stemona alkaloids. Bioassay results disclosed the anti-inflammatory natural constituents stemjapines A and C with IC50 values of 19.7 and 13.8 µM, respectively, compared to positive control dexamethasone with 11.7 µM. The findings may point out a new direction of Stemona alkaloids inaddition to its traditional antitussive and insecticide activities. [ABSTRACT FROM AUTHOR]

Both in situ and ex situ conservation are important strategies for protecting threatened plant species. Nevertheless, the success of conservation depends on whether the plant species can naturally regenerate and accomplish its life cycle over a long-term. Here we studied the pollination biology of the threatened species Hibiscus aridicola, Amorphophallus albus, Stemona parviflora and S. japonica aiming to get data about pollination strategies, pollinators as well as mating systems. These experiments were performed at Kunming Botanical Garden (KBG) for ex situ and the plant species' natural habitat for in situ conservation. The results indicated that H. aridicola is self-compatible and had pollinators under both ex situ and in situ conditions. The other three species are all self-incompatible and a limited number of pollinators for S. parviflora and S. japonica were observed at cultivated and natural habitats. Amorphophallus albus had no pollinators at KBG but a large number of rove beetles (Atheta sp.) could be observed in the plant species' natural habitat. This resulted in a high fruit set under natural conditions (73.3%, n = 30). The results showed clearly, that appropriate pollinators for the four plant species are not present all the time and all localities, which further influences the reproduction success of a plant species. Hence, for a successful conservation, it is vital to assess the species reproduction strategy prior deciding whether in situ and/or ex situ conservation should be carried out. [ABSTRACT FROM AUTHOR]

Stemona japonica is a species of perennial, flowering and herbaceous vines in the genus Stemona and the family Stemonaceae. In this study, we presented and annotated the complete chloroplast genome of S. japonica, which the chloroplast genome length was 154,224 bp, containing a large single-copy region (LSC) of 82,118 bp, a small single-copy region (SSC) of 17,938 bp and two same inverted repeat regions (IR) of 27,084 bp. The cp genome of S. japonica comprised 134 genes that included 88 protein-coding genes (PCGs), 38 transfer RNA (tRNA) genes and 8 ribosomal RNA (rRNA) genes. The overall nucleotide of cp genome composition is: A of 47,338 bp (30.7%), T of 48,206 bp (31.3%), C of 29,528 bp (19.1%), and G of 29,101 bp (18.9%), with a total A + T content of 62.0% and G + C content of 38.0%. Phylogenetic Neighbor-Joining (NJ) analysis based on 11 plants species chloroplast genomes with Stemona japonica, the result shown that Stemona japonica is closely related to Stemona mairei in evolutionary relationship.

The chemical origin and biological role of distinct semen-like odor occasionally found in some flowers are very curious but remain scarcely studied. Here, we used direct ambient corona discharge ionization mass spectrometry (MS) to study the volatile chemical composition behind the semen-like odor emitted by the fresh flowers of Photinia serrulata , Castanopsis sclerophylla and Stemona japonica without any chemical pretreatment. Chemical identification was performed using high-resolution MS analysis in combination with tandem MS analysis and whenever possible was confirmed by the analysis of standard reference compounds. A total of 19 compounds, mostly belonging to nitrogenous volatiles, were identified in P. serrulata , C. sclerophylla , and S. japonica flowers, 1-pyrroline, 1-piperideine, 2-pyrrolidone, and phenethylamine being common in all the three studied species. Several lines of evidence indicate that the major component responsible for the semen-like odor is most likely 1-pyrroline. 1-Pyrroline is most probably formed via the oxidative deamination of putrescine, as indicated by the observation of signal from 4-amino-butanal intermediate. Flower visitation observations suggest that the released volatiles serve to attract dipterans, including Syrphidae, Calliphoridae, and Muscidae. On the analytical side, the comparison of our results to earlier studies also indicate that compared to the traditional GC-MS approach the direct corona discharge ionization mass spectrometry provides more sensitive detection of VOCs with high proton affinity, in particular volatile amines, and therefore can be used to complement traditional GC-MS approach for the highest chemical coverage of VOC analysis. [ABSTRACT FROM AUTHOR]

Stemona japonica is a species of perennial, flowering and herbaceous vines in the genus Stemona and the family Stemonaceae. In this study, we presented and annotated the complete chloroplast genome of S. japonica, which the chloroplast genome length was 154,224 bp, containing a large single-copy region (LSC) of 82,118 bp, a small single-copy region (SSC) of 17,938 bp and two same inverted repeat regions (IR) of 27,084 bp. The cp genome of S. japonica comprised 134 genes that included 88 protein-coding genes (PCGs), 38 transfer RNA (tRNA) genes and 8 ribosomal RNA (rRNA) genes. The overall nucleotide of cp genome composition is: A of 47,338 bp (30.7%), T of 48,206 bp (31.3%), C of 29,528 bp (19.1%), and G of 29,101 bp (18.9%), with a total A + T content of 62.0% and G + C content of 38.0%. Phylogenetic Neighbor-Joining (NJ) analysis based on 11 plants species chloroplast genomes with Stemona japonica, the result shown that Stemona japonica is closely related to Stemona mairei in evolutionary relationship. [ABSTRACT FROM AUTHOR]

Three new dihydrostilbenes, stilbostemins P-R (1-3), and a new dihydrophenanthrene, stemanthrene G (4), were isolated from the roots of Stemona japonica together with three known bibenzyls, 3,5-dihydroxy-2'-methoxy bibenzyl (5), 3,3'-dihydroxy-2,5'-dimethoxy bibenzyl (6), and 3,5,2'-trihydroxy-4-methyl bibenzyl (7). Their structures were elucidated by spectroscopic analyses. Compounds 5 and 6 exhibited strong antifungal activities against Candida albicans. [ABSTRACT FROM AUTHOR]

Three new dihydrostilbenes, stilbostemins J–L (1–3), and a new dihydrophenanthrene, stemanthrene F (4), were isolated from the roots of Stemona japonica together with two known bibenzyls, 3,5-dihydroxy-4-methylbibenzyl (5) and 3,5-dihydroxy-2′-methoxy-4-methylbibenzyl (6). Their structures were elucidated by spectroscopic analyses. Compounds 3–6 exhibited strong antibacterial activities against Staphylococcus aureus and Staphylococcus epidermidis . [ABSTRACT FROM AUTHOR]