药用植物华重楼(黑药花科)叶绿体全基因组研究

为探究华重楼(Paris polyphylla var. chinensis)的叶绿体基因组特征,利用叶绿体系统发育基因组学方法,对华重楼与其它百合目植物的叶绿体全基因组进行了比较。结果表明,华重楼的叶绿体全基因组长158307 bp,由4个区组成,包括2个反向重复区(IRA和IRB,27473 bp)、1个小单拷贝区(SSC,18175 bp)和1个大单拷贝区(LSC,85187 bp)。其叶绿体基因组有115个基因,包括81个编码蛋白质基因、30个转运RNA基因和4 个核糖体RNA基因。11种百合目植物的叶绿体全基因组的基因组成和基因顺序相似。华重楼的cemA基因是假基因,其起始密码子后有多聚核苷酸poly(A)及CA双核苷酸重复序列,编码序列中出现多个终止密码子, 且与北重楼(Paris verticillata)的cemA编码序列中的终止密码子位置不同。因此,华重楼叶绿体基因组比较保守;cemA结构及假基因化现象可能具有重要的进化与系统发育信息,其编码序列中的终止密码子可以区分华重楼和北重楼。     

Coleifolides A and B,Two New Sesterterpenoids from the Aerial Parts of Scutellaria coleifolia H.Lév.

Coleifolides A and B ( 1 and 2 ), two new sesterterpenoids with a β‐methyl‐α,β‐unsaturated‐γ‐lactone moiety, were isolated from the aerial parts of Scutellaria coleifolia H.Lév . (Lamiaceae), together with three known compounds. Their structures were elucidated by NMR and MS examinations. Coleifolides A and B were concluded to be partially racemic compounds by the HPLC analysis using a chiral column or introduction of chiral derivatizing agents. The absolute configuration of the major isomer was determined by analyses of the CD spectrum as well as NMR data of (R)‐ and (S)‐2‐NMA derivatives. Coleifolides A and B are structurally similar to manoalide derivatives, previously isolated from marine sponges, and appear to be the first examples of this type of compounds being isolated from higher plants.     

Heart rot hotel: fungal communities in red-cockaded woodpecker excavations

Tree-cavity excavators such as woodpeckers are ecosystem engineers that have potentially complex but poorly documented associations with wood decay fungi. Fungi facilitate cavity excavation by preparing and modifying excavation sites for cavity excavators. Associations between fungi and endangered red-cockaded woodpeckers (RCWs) are particularly interesting because these are the only birds that specialize in excavating into the heartwood of living pines, a process that takes years to complete. Using molecular methods, we examined fungal communities in complete and incomplete RCW excavations, and non-cavity control trees. In addition to finding a high diversity of fungi, we found three groupings of fungal communities corresponding to the three groups of trees sampled. We show that trees selected for cavity excavation by RCWs are infected by distinct fungal communities, and propose two hypotheses to explain this outcome: the bird facilitation hypothesis and the tree selection hypothesis.     

Xanthine oxidase inhibitors isolated from Piper nudibaccatum

Two new hydroxychavicol analogs nudibaccatumin A (1) and B (2), together with twenty known compounds were isolated from the methanol extract of Piper nudibaccatum. Their structures were elucidated by extensive spectroscopic analyses (1D and 2D NMR, HRESIMS, UV, IR and polarimetry). Hydroxychavicol is a known inhibitor of xanthine oxidase (XO). In the present study, hydroxychavicol and 5 natural analogs (1–5) were evaluated for their XO inhibitory activity. Neotaiwanensol B (3) (IC₅₀ = 0.28 μM) showed a greater inhibitory effect than hydroxychavicol and allopurinol (the positive control). Two new compounds 1 and 2 showed a moderate inhibition activity with an IC₅₀ value of 62.94 μM and 70.67 μM, respectively.     

N-Substituted acetamide glycosides from the stems of Ephedra sinica

Five new N-mono-/bis-substituted acetamide glycosides, N-{4-O-[3-O-(4-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (1), N-methyl-N-{4-O-[3-O-(4-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (2), N-methyl-N-{4-O-[3-O-(6-O-benzoyl-4-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (3), N-methyl-N-{4-O-[3-O-(6-O-benzoyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (4), and N-methyl-N-{4-O-[3-O-(6-O-trans-cinnamoyl-4-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (5), along with one known acetamide derivative, N-methyl-N-(4-hydroxyphenethyl)-acetamide, the shared aglycone of 2–5, were isolated from the ethanol extract of the stems of Ephedra sinica. The structures of these new compounds were elucidated on the basis of extensive spectroscopic examination, mainly including multiple 1D and 2D NMR and HRESIMS examinations, and qualitative chemical tests. All N,N-bissubstituted acetamide glycosides were found to show the obvious rotamerism, as in the case of the isolated known N-methyl-N-(4-hydroxyphenethyl)-acetamide, under the experimental NMR conditions, with the ratios of integrated intensities between anti- and syn-rotamers always being found to be about 4 to 3.     

Chemical constituents from Euphorbia hirta

Thirty-one compounds, including fourteen triterpenoids (1–14), seven coumarins (15–21), four lignans (22–25), and six diterpenes (26–31) were isolated from the aerial part of Euphorbia hirta. The structures were elucidated by spectroscopic methods and by comparison of their reported spectroscopic data. These compounds have shown the chemical relationships between this plant and other species from the genus Euphorbia.     

The sesquiterpenoids and their chemotaxonomic implications in Senecio L. (Asteraceae)

Sesquiterpenoids are important characteristic compounds in Asteraceae plants. These compounds have been proposed to be potential chemotaxonomic markers, but this application has not been comprehensively investigated. In this paper, sesquiterpenoids from 149 species of the genus Senecio were investigated to assess their taxonomic utility. The presence and absence were encoded as binary taxonomic characteristics and subsequently utilised in a clustering analysis. The previously biosynthesis pathway of sesquiterpenoids was taken into account to explore the relationship among these species contained different sesquiterpenoid types. In addition, the DNA phylogeny was also considered to explore the distribution and evolution of sesquiterpenoids in genus Senecio further. As a result, seven chemical major sections within the Senecio were recognised based on the chemical character. Although with several exceptions, the biosynthesis pathway, molecular phylogeny and the geographical origin of these sesquiterpenoid were found to be related to the chemical sections, which largely confirmed the validity of our chemo-classification for genus Senecio. In conclusion, we suggest that the sesquiterpenoid character in Senecio has some value for the genus taxonomy but should be analysed carefully and critically.     

Chemotaxonomic significance of sesquiterpenes and amide derivatives from Chloranthus angustifolius Oliv.

Phytochemical investigation of the aerial parts of Chloranthus angustifolius Oliv. (Chloranthaceae) resulted in the isolation and characterization of seven sesquiterpenes (1–7) and six amide derivatives (8–13). All structures were established based on analysis of their spectroscopic data. This is the first report of compounds 2 and 8–13 from the family Chloranthaceae, and the first report of compounds 3–5 from C. angustifolius. Moreover, the chemotaxonomic significance of these compounds was summarized.