Cytotoxic Natural Products Isolated from Cryptogramma crispa (L.) R. Br.

Parsley fern, Cryptogramma crispa, is a common fern in arctic-alpine regions, and even though this species has been known since ancient times and has been presumed to cause the poisoning of horses, its natural products have not previously been investigated. Here, we characterise 15 natural products isolated from the aerial parts of Cryptogramma crispa, including the previously undescribed compound 3-malonyl pteroside D. The structure determinations were based on several advanced 1D and 2D NMR spectroscopic techniques, Circular Dichroism spectroscopy and high-resolution mass spectrometry. The pteroside derivatives exhibited selective moderate cytotoxic activity against the acute myeloid leukaemia MOLM13 cell line and no cytotoxicity against the normal heart and kidney cell lines, suggesting that their potential anticancer effect should be further investigated.

Natural Products from Leaves of the Ancient Iranian Medicinal Plant Echium amoenum Fisch. & C. A. Mey.

For several millennia, leaves of Echium amoenum Fisch. & C. A. Mey., an important Iranian medicinal plant with nutritional value as nutraceutical, have been used as tea for the treatment of several conditions, including inflammation. The nutritional value of intake of E. amoenum tea has mainly been correlated to its rich content of mainly water-soluble antioxidants. Although the entire plant is utilized, only natural products of the flowers have previously been thoroughly investigated. The rare natural products bis(3-(3,4-dihydroxyphenyl)-1-methoxy-1-oxopropan-2-yl)-1-(3,4-dihydroxyphenyl)-6,7-dihydroxy-1,2-dihydronaphthalene-2,3-dicarboxylate, 4-Oxy-(E)-caffeoyl-2,3-dihydroxybutanoic acid methyl ester and 4-Oxy-(Z)-caffeoyl-2,3-dihydroxybutanoic acid methyl ester, in addition to the widely distributed compounds rosmarinic acid methyl ester and (E)-caffeic acid, were purified and characterized from leaves of Echium amoenum. The structures were determined by a combination of several 2D NMR spectroscopic techniques, circular dichroism spectroscopy and high-resolution mass spectrometry. The fact that bis(3-(3,4-dihydroxyphenyl)-1-methoxy-1-oxopropan-2-yl)-1-(3,4-dihydroxyphenyl)-6,7-dihydroxy-1,2-dihydronaphthalene-2,3-dicarboxylate belongs to a rare group of natural products which have previously been patented for their significant anti-inflammatory activity may rationalize the traditional treatment of inflammations with E. amoenum.

Detecting destabilizing species in the phylogenetic backbone of Potentilla (Rosaceae) using low-copy nuclear markers.

The genus Potentilla (Rosaceae) has been subjected to several phylogenetic studies, but resolving its evolutionary history has proven challenging. Previous analyses recovered six, informally named, groups: the Argentea, Ivesioid, Fragarioides, Reptans, Alba and Anserina clades, but the relationships among some of these clades differ between data sets. The Reptans clade, which includes the type species of Potentilla, has been noticed to shift position between plastid and nuclear ribosomal data sets. We studied this incongruence by analysing four low-copy nuclear markers, in addition to chloroplast and nuclear ribosomal data, with a set of Bayesian phylogenetic and Multispecies Coalescent (MSC) analyses. A selective taxon removal strategy demonstrated that the included representatives from the Fragarioides clade, P. dickinsii and P. fragarioides, were the main sources of the instability seen in the trees. The Fragarioides species showed different relationships in each gene tree, and were only supported as a monophyletic group in a single marker when the Reptans clade was excluded from the analysis. The incongruences could not be explained by allopolyploidy, but rather by homoploid hybridization, incomplete lineage sorting or taxon sampling effects. When P. dickinsii and P. fragarioides were removed from the data set, a fully resolved, supported backbone phylogeny of Potentilla was obtained in the MSC analysis. Additionally, indications of autopolyploid origins of the Reptans and Ivesioid clades were discovered in the low-copy gene trees.

A novel poly-oxygenated flavone glucoside from aerial parts of the Brazilian plant Neoglaziovia variegata (Bromeliaceae).

Neoglaziovia variegata is endemic to northeastern Brazil. The drought resistant plant produces edible fruits and is used as a fibre plant by rural communities in the Caatinga region where a variety of products are made from the white, soft and flexible fibres. Extracts of N. variegata have been reported to be of low toxicity and to exhibit antinociceptive effect, photoprotective potential, antioxidant effect, gastroprotective effects and antibacterial effect against both Gram-positive and Gram-negative bacteria, however, the chemical constituents of this species are mainly unknown. The novel poly-oxygenated flavone glucoside 5,6,7,4'-tetrahydroxy-3',5'-dimethoxy-flavone 7-O-ß-glucopyranoside in addition to the rare poly-oxygenated flavone 5,4'-dihydroxy-6,7,3'-trimethoxyflavone 4'-O-ß-glucopyranoside and the flavonol quercetin 3-O-(6''-rhamnopyranosyl-ß-glucopyranoside) have been characterised from the leaves of N. variegata. 5,6,7,4'-tetrahydroxy-3',5'-dimethoxy-flavone, which comprises the core structure of the novel compound, is a new flavonoid aglycone in nature. The structure determinations were based on extensive use of 2D NMR spectroscopic techniques and high-resolution mass spectrometry. Both substances exhibited toxicity towards MOLM-13 acute myeloid leukaemia cells.

Growing with dinosaurs: natural products from the Cretaceous relict Metasequoia glyptostroboides Hu & Cheng-a molecular reservoir from the ancient world with potential in modern medicine.

After the sensational rediscovery of living exemplars of the Cretaceous relict Metasequoia glyptostroboides-a tree previously known exclusively from fossils from various locations in the northern hemisphere, there has been an increasing interest in discovery of novel natural products from this unique plant source. This article includes the first complete compilation of natural products reported from M. glyptostroboides during the entire period in which the tree has been investigated (1954-2014) with main focus on the compounds specific to this plant source. Studies on the biological activity of pure compounds and extracts derived from M. glyptostroboides are reviewed for the first time. The unique potential of M. glyptostroboides as a source of bioactive constituents is founded on the fact that the tree seems to have survived unchanged since the Cretaceous era. Since then, its molecular defense system has resisted the attacks of millions of generations of pathogens. In line with this, some recent landmarks in Metasequoia paleobotany are covered. Initial spectral analysis of recently discovered intact 53 million year old wood and amber of Metasequoia strongly indicate that the tree has remained unchanged for millions of years at the molecular level.