Alkaloids as taxonomic characters in the tribe Crotalarieae (Fabaceae)

Recent studies of alkaloids have led to a better understanding of the intricate taxonomic relationships in the tribe Crotalarieae. Data from alkaloidal metabolites are largely congruent with morphological data, but allow refinement of the understanding of the phylogeny. A well-supported and almost fully resolved cladogram is presented, which shows that the genera can be grouped into four main clades: (1) an unspecialized group without -pyridone alkaloids and without esters of alkaloids (Aspalathus, Lebeckia, Rafnia, Wiborgia and perhaps Spartidiurn); (2) a group specializing in lupanine-type esters (Pearsonia and Rothia); (3) a group with macrocyclic pyrrolizidine alkaloids (Crotalaria andLotononis); and (4) a specialized group with -pyridone alkaloids (Argyrolobium, Dichilus, Melolobium and Polhillia).     

Pyrrolizidine alkaloids from Neurolaena lobata

Neurolaena lobata was investigated for the occurrence of pyrrolizidine alkaloids. The untypical methyl ester alkaloids tussilagine, isotussilagine and their possible biosynthetic precursor 2-pyrrolidineacetic acid were found in the methanolic leaf extract. As previously found for Arnica species and Tussilago farfara, all methyl esters are artifacts derived from the corresponding acids during Soxhlet extraction. The occurrence of toxic necines, often found in the Senecioneae, could be ruled out.     

Chemotaxonomic significance of alkaloids in the genus Robynsiophyton

The alkaloids of the monotypic genus Robynsiophyton have been studied for the first time. Most of the quinolizidine alkaloids and esters of quinolizidine alkaloids found in the genus Pearsonia are also the major compounds in Robynsiophyton. These include lupanine, 3β-hydroxylupanine, lebeckianine, lupanine-13-angelate, cajanifoline, cryptanthine, sessilifoline and pearsonine. The results support the idea of a close affinity between Robynsiophyton, Pearsonia and Rothia. Except for the apparent absence of tigliate esters in Pearsonia, differences between the genera seem quantitative only.     

花椒属植物生物碱与其两个亚属合并问题

花椒属植物约有250余种,大多分布于美洲、澳洲、非洲及亚洲。我国约有50余种,按Enzler分组法属于Mocqueria Triana et planch组,Paniculatae Engl.系,Gerontogaeae Engl.群^{[1] [2]}。1931年Engler在其"Die Natürlichen pflanzenfamilien"一书中谈到他经过长期考虑后,决定将原来的花椒属分为两个亚属即Zanthoxylum亚属和Fagara亚属。     

The evolution of pyrrolizidine alkaloid diversity among and within Jacobaea species

Plants produce many secondary metabolites showing considerable inter- and intraspecific diversity of concentration and composition as a strategy to cope with environmental stresses. The evolution of plant defenses against herbivores and pathogens can be unraveled by understanding the mechanisms underlying chemical diversity. Pyrrolizidine alkaloids are a class of secondary metabolites with high diversity. We performed a qualitative and quantitative analysis of 80 pyrrolizidine alkaloids with liquid chromatography-tandem mass spectrometry of leaves from 17 Jacobaea species including one to three populations per species with 4–10 individuals per population grown under controlled conditions in a climate chamber. We observed large inter- and intraspecific variation in pyrrolizidine alkaloid concentration and composition, which were both species-specific. Furthermore, we sequenced 11 plastid and three nuclear regions to reconstruct the phylogeny of the 17 Jacobaea species. Ancestral state reconstruction at the species level showed mainly random distributions of individual pyrrolizidine alkaloids. We found little evidence for phylogenetic signals, as nine out of 80 pyrrolizidine alkaloids showed a significant phylogenetic signal for Pagel's λ statistics only, whereas no significance was detected for Blomberg's K measure. We speculate that this high pyrrolizidine alkaloid diversity is the result of the upregulation and downregulation of specific pyrrolizidine alkaloids depending on ecological needs rather than gains and losses of particular pyrrolizidine alkaloid biosynthesis genes during evolution.     

Chloroform-soluble alkaloids of the root bark of Fagara viridis

Three alkaloids have been isolated from the root bark of Fagara viridis A. Cheval. (Rutaceae). One of these, canthin-6-one, is reported for the first time from an African species of Fagara while the others are the quaternary benzophenanthridine alkaloids chelerythrine and nitidine.     

Berberine contents and alkaloid profile of Berberis species from different altitudes

Roots, stem and leaves of eight species of Berberis collected from different altitudes in Garhwal, Himilaya, were analysed for berberine. Lowland species and types were found to have considerably higher berberine contents in all plant parts than sub-alpine and alpine species. In all, 12 or more alkaloids were separable in these species. Based on the similarity coefficient of leaf alkaloids, B. nepalensis was found to be identical to B. asiatica and B. vulgaris was identical to B. lycium. It is suggested that the concentration of berberine is probably a result of adaptive response to altitudinal gradient in addition to it being a genetic character of different species of Berberis.     

Alkaloids from stem barks of Oricia renieri and Oricia gabonensis

The stem barks of Oricia renieri and O. gabonensis have yielded nine alkaloids, including furoquinolines, acridones, 3,4-pyrano-2-quinolones and a 2-amino-benzophenone. One of the pyranoquinolones isolated from O. renieri, 7-methoxy-N-methylflindersine, is reported for the first time. All alkaloids were identified on the basis of spectral data. The chemotaxonomic significance of the alkaloids of these two species is discussed.     

A survey of alkaloids in the genera Harpalyce and Brongniartia (Fabaceae—Brongniartieae)

The presence of alkaloids in six species of Brongniartia and three species of Harpalyce is reported. This survey revealed remarkable qualitative differences in the alkaloid profiles of these two genera. B. discolor, B. lupinoides, B. sousae and B. intermedia showed a typical -pyridone pattern, with cytisine, anagyrine and baptifoline as major alkaloids. In leaves of the first three species ormosanine-type alkaloids occurred additionally. B. flava and B. vazquezii are devoid of -pyridones, but accumulate lupanine, hydroxylated lupanines and ester alkaloids. All three species of Harpalyce were similar in accumulating -pyridones, but H. formosa differed from H. brasiliana and H. pringlei in the presence of epilupinine. In general the alkaloid profiles of Brongniartia and Harpalyce show similarities to those of the Australian genera Hovea, Lamprolobium, Plagiocarpus and Templetonia and support therefore the actual concept of the enlarged tribe Brongniartieae.     

Alkaloids of some south american erythroxylum species

Fourteen South American species of Erythroxylum representing four sections of the genus were examined for tropane and related alkaloids. The alkaloid content of the dried material ranged from 0.002 to 0.20 %. Commonly, the alkaloids involved were esters of various tropanols with benzoic and phenylacetic acids. A new alkaloid, nortropacocaine, was isolated from E. mamacoca. Mass spectrometry indicated the existence of other new bases, cuscohygrine and, in some species dihydrocuscohygrine. Chemotaxonomic implications are discussed.     

Esterification reactions in the biosynthesis of tropane alkaloids in transformed root cultures

Transformed root cultures of Datura stramonium and of related species contain both aliphatic and aromatic tropane esters. It has been shown that these esters are produced by the action of several acyl transferases that transfer the acidic moiety to tropan-3-ol (tropine) or tropan-3-ol (pseudotropine) from various acyl-coenzyme A thioesters. The presence of these enzymes has been examined in a range of tropane-alkaloid-producing and non-tropane-alkaloid-producing species. Activities that esterify tropine appear to be confined to species that accumulate tropane alkaloids, whereas a number of species that do not accumulate tropane alkaloids possess some ability to esterify pseudotropine.The present state of knowledge of these enzymes is reviewed. One of these activities, tigloyl-Coenzyme A:pseudotropine acyl transferase, has been purified to near homogeneity and the properties of this enzyme are summarized.Abbreviations CoA coenzyme A - gc gas chromatography - ms mass spectrometry     

Taxonomic significance of alkaloids and iridoid glucosides in the tribe Psychotrieae (Rubiaceae)

Leaves of 15 Brazilian species of Psychotria, three of Rudgea and Palicourea rigida, were analyzed for their alkaloid and iridoid content. Alkaloids were found in three of Rudgea and 14 species of Psychotria, and iridoids were found in Psychotria leiocarpa, which produces asperuloside and deacetylasperuloside. Palicourea rigida yielded no alkaloids but loganin was isolated. The results illustrate the significance of the alkaloids in the chemotaxonomy of some taxa of Psychotrieae. The phytochemical data indicate that the American species of Psychotria with Palicourea could be joined to form the genus Heteropsychotria.     

Occurrence of pyrrolizidine alkaloids in three Ethiopian Solanecio species

Three Ethiopian Solanecio species, namely Solanecio angulatus (Vahl) C. Jeffrey, Solanecio mannii (Hook. f.) C. Jeffrey, and Solanecio tuberosus (Sch. Bip. ex A. Rich.) C. Jeffrey var. tuberosus were analysed by capillary gas chromatography–mass spectrometry (GLS–MS) for their pyrrolizidine alkaloid content. All the extracts investigated contain pyrrolizidine alkaloids. Whilst only traces of alkaloids could be detected in the leaf extract of S. angulatus, the content of alkaloids in the other samples ranged between 0.13% dry weight (for the flowers of S. angulatus) and 0.58% (for the tubers of S. tuberosus). Altogether 17 alkaloids were detected out of which 14 were unambiguously identified by comparing their retention indices, molecular masses and mass fragmentation patterns with defined reference data from PAs database or in some cases with reference compounds. The hepatotoxic macrocyclic diesters senecionine and retrosine figured as major alkaloids in the flowers of S. angulatus, whereas the platynecine type alkaloid, 7-O-senecioylplatynecine occurred in higher amount than the other alkaloids detected in the leaves of S. mannii. The tuberous annual herb, S. tuberosus contains eruciflorine as a major alkaloid in the leaves, flowers and tubers. Senecionine figures as one of the major components of the tubers of S. tuberosus. To the best of our knowledge this is the first published report on the occurrence of pyrrolizidine alkaloids in the genus Solanecio. In addition to the chemotaxonomic significance of the detected alkaloids, a brief remark is made on the findings in the light of the use of these plants as medicinal herbs and/or as nectar or pollen source for the production of honey.     

Biotechnology of ergot alkaloids

The ergot alkaloids are a group of pharmacologically active compounds produced primarily by species of Claviceps, a fungal parasite of grasses and cereals.

Ergot is of historical interest: medieval midwives collected the fungus from naturally infected plants and used it in the induction of childbirth and in the control of postpartum bleeding. Many additional uses of the ergot alkaloids have been discovered since then, and yet the method of production has persisted to this day basically unchanged.

However, submerged culture of Claviceps is starting to supersede the use of systematically infected rye and a number of new opportunities, including the development of high yielding fungal strains and the production of semi-synthetic alkaloids, have become apparent.     

Chemistry of Cirsium and Carduus: a role in ecological risk assessment for biological control of weeds?

Prediction of host plant range and ecological impact of exotic phytophagous insects, such as insects for classical biological control of weeds, represents a major challenge. Recently, the flowerhead weevil (Rhinocyllus conicus Fröl.), introduced from Europe into North America to control exotic thistles (Carduus spp.), has become invasive. It feeds heavily on some, but not all species of native North American thistles (Cirsium spp.). We hypothesized that such non-target use among native plants could be better predicted by knowledge of characteristic chemical profiles of secondary compounds to supplement the results of host specificity testing. To evaluate this hypothesis, we reviewed the literature on the chemistry of Cirsium and Carduus thistles. We asked what compounds are known to be present, what is known about their biological activity, and whether such information on chemical profiles would have better predicted realized host range and ecological effects of R. conicus in North America. We found an extensive, but incomplete literature on the chemistry of true thistles. Two main patterns emerged. First, consistent chemical similarities and interesting differences occur among species of thistles. Second, variation occurs in biologically active groups of characteristic compounds, specifically flavonoids, sterols, alkaloids and phenolic acids, that are known to influence host plant acceptance, selection, and feeding by phytophagous insects. Surprisingly, sesquiterpene lactones, which are characterisitic in closely related Asteraceae, have not been extensively reported for Cirsium or Carduus. The minimal evidence on sesquiterpene lactones may reflect extraction methods vs. true absence. In summary, our review suggests further research on thistle chemistry in insect feeding is warranted. Also, since the exotic Canada thistle (Cirsium arvense) is an invasive thistle of current concern in North America, such research on mechanisms underlying host range expansion by exotic insects would be useful.     

一种快速定量分析药用植物淫羊藿生物碱的方法

建立了基于近红外漫反射光谱的药用植物淫羊藿(Epimedium)生物碱的定量分析方法,测定了9种淫羊藿生物碱的含量。当聚类分析采用主成分分析、数学处理采用2,4,4,1模式、光谱散射校正采用标准正则变换+散射处理及回归分析采用改进最小二乘法时,淫羊藿生物碱近红外定标模型的定量效果最好;定标方程的定标决定系数、交互验证相关系数、定标标准差和交互验证标准差分别为0.899 7、0.845 7、0.168 6和0.085 3。近红外定标模型预测值与常规化学分析值差异很小。应用近红外漫反射光谱法测得9种淫羊藿生物碱的含量介于6.537–20.586 mg·g–1(干重)之间,淫羊藿生物碱的种间差异较大。近红外漫反射光谱法具有快速、简便和无损(不损耗受检材料)的优点,可用于淫羊藿生物碱的研究与开发。     

Phenetic relationships among varanid lizards based upon comparative electrophoretic data and karyotypic analyses

Comparative electrophoretic phenotypes of 18 of the 32 species of the lizard genus Varanus have been determined for four proteins. The animals studied were representative of species from Africa, Israel, Southeast Asia and Australia. Malate dehydrogenase (A₂) exhibited a single phenotype throughout. Lactate dehydrogenase (B₄) showed four distinctive electrophoretic forms which grouped the various subgenera as follows: (1) Polydaedalus, Empagusia (African); (2) Psammosaurus (Israel); (3) three species of Varanus, V. gouldii, V. spenceri, V. mertensi (Australian); (4) Dendrovaranus, Indovaranus (Southeast Asian), other Varanus species, Odatria (Australian). Electrophoretic and previously reported karyotypic data were used to interpret the phylogenetic relationships as well as the mode and direction of evolution of these animals. In particular, the results questioned the reality of the subgenus Varanus as a taxonomic unit, since four distinct karyotypic forms and two LDH-B₄ phenotypes were observed for these animals, of which one belongs to another subgenus. Serum albumin and carbonic anhydrase phenotypes were of little use in deciding phenotypic groupings.     

Phylogenetic selection of Narcissus species for drug discovery

Plants are of immense importance in providing healthcare worldwide. With over 250 000 species of angiosperms alone, the potential for finding new medicinal plants and lead compounds for drug development is enormous. Some way of selecting plants for drug discovery programs is necessary. Phylogenies have great explanatory power and also enable a predictive perspective not offered by previous classifications of plants. Phylogenetic selection of target species is a new approach to drug discovery and the present study is the first attempt to correlate acetylcholine esterase (AChE) inhibitory activity and alkaloid distribution with a molecular phylogenetic hypothesis of Narcissus. The distribution of alkaloids with AChE inhibitory activity is significantly constrained by the phylogeny. Simultaneous evaluation of all available information of alkaloids and AChE inhibitory activity in a phylogenetic framework allowed us to discuss various strategies for selection of target species for further studies of AChE inhibitory activity.     

Alkaloids of Antizoma miersiana (Menispermaceae)

The main alkaloids of Antizoma miersiana and one of two species of the southern African endemic genus Antizoma (Menispermaceae), have been studied for the first time. Eight isoquinoline alkaloids could be positively identified (structural type in brackets): crotsparine (proaporphine); bulbocapnine and dicentrine (aporphine); cissacapine, cycleaneonine, cycleanine, insulanoline and insularine (bisbenzyltetrahydroisoquinoline). Crotsparine and bulbocapnine were the main alkaloids in the leaves, while bulbocapnine, dicentrine, insulanoline and an unidentified alkaloid are the major compounds in stems. The rhizome contains small amounts of all except crotsparine. There are clear differences, not only between various plant parts, but also between the two species of Antizoma. Bulbocapnine, for example, was previously found to be absent from the leaves and stems of Antizoma angustifolia. Dicentrine is absent from the latter and therefore appears to be of further diagnostic value to distinguish between the two species. The rich variety and yield of alkaloids in A. miersiana provide a rationale for its value as a medicinal plant.     

中国牛科动物分布与种群现状: 基于文献计量数据

牛科是哺乳纲中物种数量最多的有蹄类动物类群, 在全球广泛分布, 在陆地生态系统中具有重要的生态功能与作用。我国的牛科动物多样性较高, 据历史文献记载共有33种。然而, 自20世纪中期以来, 我国人口快速扩张, 社会经济高速发展, 对环境改造强度空前, 许多野生牛科动物的种群和栖息地受到了极大的影响。因此, 历史资料记载的物种分布是否依然符合现状, 至今未见系统和全面的评估, 不利于对我国动物资源情况的掌握和保护。为此, 我们系统检索并分析了2008年至今(2020年8月31日)在国内外公开发表的432篇学术论文, 以近年报道的红外相机调查结果为核心, 对28种牛科动物的分布以及15种牛科动物的种群现状进行了初步评估。经整理分析: (1)近年公开发表的研究显示, 中国目前有确凿分布证据的野生牛科动物有28种, 包括16种国家I级和11种国家II级重点保护野生动物, 涉及20个生物多样性优先保护区域。其中, 红鬣羚(Capricornis rubidus)属于中国新记录物种。(2)在省级区划层面, 记录到牛科动物物种数量最多的是西藏(n = 11)和甘肃(n = 11), 其次是新疆(n = 10)、青海(n = 7), 以及四川、内蒙古和云南(均为6种)。(3)分布省域最多的牛科动物是中华鬣羚(Capricornis milneedwardsii, 省区, n = 16), 其次是中华斑羚(Naemorhedus griseus, n = 11)和岩羊(Pseudois nayaur, n = 8)。(4)据历史资料记载, 6种未见分布报道的牛科动物主要分布在西藏、新疆、云南, 分别是阿尔泰盘羊(Ovis ammon)、哈萨克盘羊(O. collium)、大额牛(Bos frontalis)、野水牛(B. arnee)、爪哇野牛(B. javanicus)和缅甸斑羚(Naemorhedus evansi)。(5)中华斑羚、赤斑羚(Naemorhedus baileyi)、中华鬣羚、岩羊、北山羊(Capra sibirica)、野牦牛(Bubalus arnee)在IUCN公布的分布区外有新分布记录, 建议及时修订和更新。本研究首次对中国牛科动物的分布以及种群现状进行了较客观和全面的评价, 为后续调查需要重点关注的物种和区域以及未来的研究提供参考。