Terpenoids from the leaves of Podocarpus gracilior

Three new terpenoids, 2α,16-dihydroxy-4β-carboxy-O-β-d-glucopyranosyl-19-nor-totarol (1), nagilactone K (2), and 15-hydroxy phaseic acid (3), together with nine known compounds, were isolated from the leaves of Podocarpus gracilior. Their structures were determined by means of 1D and 2D NMR spectroscopy as well as by mass spectrometry analysis.     

Biflavanoids,norditerpenes and a nortriterpene from Podocarp us urbanii

The structures of a biflavanoid, two new norditerpenes, urbalactone and 2,3-dihydropodolide, an ecdysterol, as well as a known biflavanoid, nagilactone C and podolide from Podocarpus urbanii were elucidated.     

Diterpenoids of Podocarpus nubigena

From the leaves and stems of Podocarpus nubigena Lindl. have been isolated rimuene, nagilactone-C, a new norditerpene. nubilactone-A (IV), daucosterin, sitosterol and cyanidin.     

The Chemical Constituents from Podocarpus nagi (II)

Continuing the former report, four more constituents Were isolated from the seeds of Podocarpus nagi (Thunb.) Zoll. et Mor. ex Zoll. (Podocarpaceae). They were identified as sciadopitysin (Ⅰ), amentoflavone-4', 4"', 7, 7"-tetramethyl ether (Ⅱ), nagilactone C(Ⅲ) and ethyl-β-D-pyranoglucoside (Ⅳ). Ⅰ, Ⅱ and Ⅳ were first reported in this plant. Ⅲ shows stronge cytotoxic activity.     

Growth effects of nagilactone E on cultured cells of lettuce

Nagilactone E, a norditerpene dilactone isolated from a gymnosperm, Podocarpus nagi (Podocarpaceae), was able to stimulate the growth of cultured cells of Lactuca sativa cv. Grand Rapids at 0.1 g ml^-1 but not at 0.01 or 1 g ml^-1. Cell wet weight/unit time and cell number/unit wet weight were increased when they were recorded at the end of the 14-day incubation period. Also, the population of cells treated with that concentration of nagilactone E had a higher percentage of cells with shorter cell length compared to the control (untreated).     

Biflavones from the genus Podocarpus

A new biflavonoid, podocarpusflavanone, has been isolated from Podocarpus taxifolia and identified by chemical and spectral data as I-4′,I-5,II-5-trihydroxy-II-4′,I-7,II-7-trimethoxy-I-2,3-dihydro-[I-3′,II-8]biflavone along with other biflavonoids. The distribution of biflavonyl pigments in eight Podocarpus species is outlined.     

Three new abietane diterpenoids from Podocarpus fleuryi

Three new abietane diterpenoids, fleuryinols A–C (1–3), together with fourteen known compounds, were isolated from the twigs and leaves of Podocarpus fleuryi. Their structures were established by spectroscopic analysis, including 1D- and 2D-NMR spectroscopic techniques. Compounds 1–8 were tested cytotoxic activity against five human cancer cell lines, HL-60, SMMC-772, A-549, MCF-7, and SW480, of which fleuryinol B (2) and 19-hydroxyferruginol (4) exhibited moderate cytotoxic activity against some cell lines.     

Anti-inflammatory abietane diterpenoids from the seeds of Podocarpus nagi

In searching for naturally occurring anti-inflammatory agents, three new abietane-type diterpenoids, named 16-hydroxylambertic acid (1), 7-oxo-18-hydroxyferruginol (2), and 5α,12-dihydroxy-6-oxa-abieta-8,11,13-trien-7-one (3), were isolated from the seeds of Podocarpus nagi, together with three known compounds. The structures of the new compounds were elucidated by extensive analysis of NMR and HR-ESIMS data. All the new compounds were tested for nitric oxide (NO) inhibitory activities on lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Compound 1 significantly inhibited NO production with IC₅₀ value of 5.38 ± 0.17 μM, and suppressed inducible NO synthase (iNOS) expression in a dose-dependent manner, which were mediated through inhibiting the mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) activation.     

Phenolic diterpenoids of podocarpus ferrugineus and other podocarps

19-Hydroxyferruginol and 19-acetoxyferruginol, two new naturally occurring phenolic diterpenoids, have been isolated from the heartwood of Podocarpus ferrugineus. Totarol and its derivatives have been obtained from Podocarpus affinis, P. falcatus, P. koordersii, Dacrycarpus vieillardii and Decussocarpus comptonii and podocarpic acid from Falcatifolium taxoides.     

Pestalotiopsis yunnanensis sp. nov., an endophyte from Podocarpus macrophyllus (Podocarpaceae) based on morphology and ITS sequence data

Pestalotiopsis is a common and important plant-associated pathogen and endophyte with wide geographical and host distribution. In an investigation of endophytic Pestalotiopsis species associated with Podocarpaceae in China, a new species Pestalotiopsis yunnanensis was isolated from Podocarpus macrophyllus in Kunming, southwestern China. This new species produced pycnidium-like conidiamata in culture, distinct from its morphologically similar species, P. funereoides, P. funerea and P. thujae, which produce acervuli in manual media and hosts. P. yunnanensis also possesses a greater conidium length/width ratio, and longer apical and basal appendages as its distinguishing morphology characters. Phylogenetic analysis of internal transcribed spacer (ITS) sequences showed that P. yunnanensis is a member of Pestalotiopsis, and is distinct from morphologically similar P. funereoides, P. funerea, and P. thujae, as well as other Pestalotiopsis species. A dichotomous key to 26 Pestalotiopsis species occurring on Podocarpus plants is also presented.     

Reproductive biology and population structures of Podocarpus falcatus and P. latifolius in southern Gape forests

GELDENHUYS, C. J., 1993. Reproductive biology and population structures of Podocarpus falcatus and P. latifolius in southern Cape forests This study concerns morphological differences of the fruit types of two Podocarpus species in relation to their different population recruitment rates. First, sampling data from the mixed evergreen forests of Gouna and Groenkop in the southern Cape, South Africa, were used to describe the population structures of the two species. Podocarpus falcatus is widely scattered at low density and has a low recruitment rate. Podocarpus latifolius is widespread and common at high density and has a high recruitment rate. Second, the morphology of their fruits and seeds was studied in relation to seed dispersal, predation and germination. The species represent the two basic ‘fruit’ types of the genus. Podocarpus falcatus produces a heavy fruit, but invests mostly in dispersal (with a yellow fleshy pulp or epimatium enclosing the seed) and protective tissue (stony shell or sclerotesta) and very little into endosperm food reserves for the embryo. Podocarpus latifolius produces a light fruit which is composed mainly of dispersal tissue (blackish-purple fleshy receptacle) with protective tissue (thin leathery epimatium without woody sclerotesta) and food reserves for the embryo. The structure of the P. falcatus fruit is related to adaptation for protection during seed dispersal by bats. The stony sclerotesta delays germination for about one year and thereby causes the exposure of the seed to high post-dispersal predation by rodents and bushpig. Seedling recruitment is low. In contrast birds and baboons eat the receptacle of the P. latifolius fruit and discard the seed undamaged. Less protective tissue is required. Seeds germinate within two to four months and recruitment is high. The structural differences of the two fruit types also have predictive value for the relative success of the different sections of the genus. Section Afrocarpus (to which P. falcatus belongs) and related sections have relatively restricted geographic distributions. Section Eupodocarpus (to which P. latifolius belongs) and related sections have wide distributions.     

Podoimbricatin A,a cytotoxic diterpenoid with an unprecedented 6/6/5/6-fused tetracyclic ring system from the twigs and leaves of Podocarpus imbricatus

Podoimbricatin A (1), a diterpenoid possessing an unprecedented 6/6/5/6-fused tetracyclic ring system, and podoimbricatin B (2), a new abietane-type diterpenoid, together with four previously reported diterpenoids and a cyclic peptide were isolated from the twigs and leaves of Podocarpus imbricatus. Their structures were established on the basis of extensive spectroscopic analyses and the relative configuration of 1 was confirmed by single-crystal X-ray diffraction analysis. A plausible biogenetic pathway involving hetero-Diels–Alder cycloaddition as a key reaction is proposed for 1. Compounds 1, 5, and 7 showed inhibitory effects against the A549 and NCI-H292 cancer cell lines.     

An antiproliferative norditerpene dilactone, Nagilactone C, from Podocarpus neriifolius

An ethanolic extract of Podocarpus neriifolius D. Don (Podocarpaceae) showed antiproliferative activity against two major tumor cell lines, viz. human HT-1080 fibrosarcoma and murine color 26-L5 carcinoma. Bioassay guided fractionation showed the highest antiproliferative activity in chloroform–soluble fraction. Nagilactone C, the major constituent of this fraction was isolated and characterized by using NMR, IR and FAB-MS spectroscopic methods. Nagilactone C possessed potent antiproliferative activity against human fibrosarcoma and murine colon carcinoma tumor cell lines exhibiting ED₅₀ values of 2.3 and 1.2 μg/ml, respectively. Hence, nagilactone C could be the active constituent present in this plant.     

罗汉松根瘤内生细菌的分离和特性

罗汉松Ｐｏｄｏｃａｒｐｕｓｍａｃｒｏｐｈｙｌｌｕｓ(Ｔｈｕｎｂ .)Ｄ .Ｄｏｎ是裸子植物亚门罗汉松科一种 ,在我国主产长江以南各省 ,为用材及园林绿化的优良树种 ,种子和根可入药。关于罗汉松根际微生物的研究 ,梁秀棠[1] 、花晓梅[2 ] 曾报道其根与菌根真菌共生形成外生或内生菌根。国外有学者发现 ,几种其它的罗汉松科植物Ｐ .ｎｕｂｉｇｅｎｕｓ等具有结瘤固氮现象[3～ 6] ,但对其与细菌共生形成根瘤以及根瘤内生细菌的分离鉴定至今国内外尚未见报道。作者在广西的南宁、桂林、扶绥及广东的佛山等地进行野外调查 ,证明罗汉松在自然界…     

Two New Diterpene Dilactones from Podocarpus nagi

Two new diterpene dilactones, episellowin C (1) and nagilactoside B (2), were isolated from the seeds of Podocarpus nagi (Thunb.) Zoll. et Mor. ex Zoll.. Their structures were elucidated by means of spectral analysis and chemical method. Compound 1 has strong cytotoxic activity, and compound 2 is inactive.     

Seed Development in Podocarpus henkelii: an Ultrastructural and Biochemical Study

Biochemical and fine-structural studies were undertaken on theembryo and female gametophyte of seeds of Podocarpus henkeliiduring the 24-week period of post-fertilization growth and development. Although the d. wt of the embryo and female gametophyte showeda steady increase during development, the levels of sugars,amino acids, proteins and lipids differed between seed partsand showed changes during the four sampling intervals. Onlystarch was seen to increase steadily throughout development.Lipid levels were high in the mature embryo and free amino acidsshowed a steady increase until the seeds were shed. At thisstage seeds were fully hydrated, possessed abundant reservesand all organelles appeared fully functional. This was interpretedas part of the development strategy of neotonous (recalcitrant)seeds, namely, the maintenance of full metabolic competencefor continued growth in the absence of development arrest whichfollows drying in orthodox seeds. Podocarpus henkelii, yellow wood, embryo and endosperm growth, neotonous seed, recalcitrance     

Growth dynamics and potential for cross-dating and multi-century climate reconstruction of Podocarpus falcatus in Ethiopia

Podocarpus falcatus is an indigenous evergreen conifer species of tropical mountain forests in southeastern Ethiopia, showing potential tree ages of around 500 years. To study the influence of seasonal climate on the growth pattern of P. falcatus, we combined high-resolution electronic dendrometer measurements with wood anatomical investigations of microcores from the outermost stem parts collected in monthly intervals. At any time of the year sufficient rain events are able to cause cambial activity in P. falcatus. This permanent growing readiness leads to irregular wood formation with the formation of intra-annual density fluctuations and missing rings. Wood anatomical studies of microcores collected around the circumference of a mature P. falcatus revealed locally different activity status of the cambium on different lobes of the stem. Tree-ring width measurements of stem disks resulted in tentative tree ages that were confirmed by radiocarbon dating of selected wood samples. Although our efforts to cross-date ring-width series from several stem disks were not successful, further sampling in areas with different rainfall regimes, additional radiocarbon dating and measurements of stable isotopes hopefully would enable the establishment of a multi-century-long tree-ring series for climate reconstruction.     

The Reproductive Biology of Totara (Podocarpus totara) (Podocarpaceae)

A reproductive cycle of totara (Podocarpus totara) in New Zealandis complete within 2 years. After strobilus initiation in September,there is a 9 month period of winter dormancy until emergenceduring the growth flush in July–August of the followingyear. Female strobili bear only one or two ovules which arepollinated mid-October to mid-November at the megaspore tetradstage. Pollen germination and fertilization occur rapidly duringDecember. The pollen tube carries the body cell, sterile andtube nuclei with at least three prothallial nuclei, and branchesout after reaching the archegonia. The four–six archegoniacontain egg nuclei with no distinct perinuclear zone and a largechalazal vacuole. Fertilization by the larger of the two unequalmale gametes is accompanied by a degradation of egg cell cytoplasm.The three-tier proembryo contains a binucleate embryonal tierof only one cell. Soon after embryo penetration into the megagametophyte,the binucleate embryonal-tier cell undergoes mitosis and cellwall formation resulting in four uninucleate cells. Some ovulescontained secondary embryos thought to be the product of suspensorcleavage. Embryo maturation occurs by February.Copyright 1999Annals of Botany Company Podocarpus totara, totara, conifer, podocarp, reproductive biology, embryology.     

Plasticity of stomatal distribution pattern and stem tracheid dimensions in Podocarpus lambertii: an ecological study

Background and Aims

Leaf and wood plasticity are key elements in the survival of widely distributed plant species. Little is known, however, about variation in stomatal distribution in the leaf epidermis and its correlation with the dimensions of conducting cells in wood. This study aimed at testing the hypothesis that Podocarpus lambertii, a conifer tree, possesses a well-defined pattern of stomatal distribution, and that this pattern can vary together with the dimensions of stem tracheids as a possible strategy to survive in climatically different sites.

Methods

Leaves and wood were sampled from trees growing in a cold, wet site in south-eastern Brazil and in a warm, dry site in north-eastern Brazil. Stomata were thoroughly mapped in leaves from each study site to determine a spatial sampling strategy. Stomatal density, stomatal index and guard cell length were then sampled in three regions of the leaf: near the midrib, near the leaf margin and in between the two. This sampling strategy was used to test for a pattern and its possible variation between study sites. Wood and stomata data were analysed together via principal component analysis.

Key Results

The following distribution pattern was found in the south-eastern leaves: the stomatal index was up to 25 % higher in the central leaf region, between the midrib and the leaf margin, than in the adjacent regions. The inverse pattern was found in the north-eastern leaves, in which the stomatal index was 10 % higher near the midrib and the leaf margin. This change in pattern was accompanied by smaller tracheid lumen diameter and length.

Conclusions

Podocarpus lambertii individuals in sites with higher temperature and lower water availability jointly regulate stomatal distribution in leaves and tracheid dimensions in wood. The observed stomatal distribution pattern and variation appear to be closely related to the placement of conducting tissue in the mesophyll.