Alkaloids from the seeds of Sterculia lychnophora (Pangdahai)

Two alkaloids, named sterculinine I and sterculinine II, together with thirteen known compounds were isolated from the ethanol extract of a well-known Chinese traditional drug, Pangdahai (the seeds of Sterculia lychnophora Hance). Their structures were elucidated by NMR, UV, IR and MS spectroscopic analysis.     

Secondary metabolites from Spiranthes sinensis (Orchidaceae)

One new flavonol glycoside (1) and nine known compounds (2–10) were obtained from the n-BuOH soluble fraction of the whole plants of Spiranthes sinensis. The structure of compound 1 was elucidated based on the combination of spectroscopic (¹H-NMR, ¹³C-NMR, HSQC, and HMBC as well as HR-ESI-MS) and chemical methods. The occurrences of eight compounds (2-9) in this genus were firstly reported while five of them (2–6) were obtained from Orchidaceae for the first time. Furthermore, the chemotaxonomic significance of these compounds was discussed.     

Phenolic compounds and ecdysteroids of Diplazium esculentum (Retz.) Sw. (Athyriaceae) from Japan and their chemotaxonomic significance

Four phenolic compounds, (2R)-3-(4′-hydroxyphenyl) lactic acid, trans-cinnamic acid (2), protocatechuic acid (3) and rutin (4), and three ecdysteroids, amarasterone A1 (5), makisterone C (6) and ponastrone A (7) were isolated and identified from the young fronds of Diplazium esculentum (Retz.) Sw. (Athyriaceae). The structures of these compounds were elucidated on the basis of NMR spectral data and comparison with literature values. Compounds 1, 2 and 5–7 were isolated for the first time from title plant. Their structure elucidation and chemotaxonomic significance are explained in detail.     

Chemical constituents from Orobanche cernua Loefling

Phytochemical study of Orobanche cernua Loefling afforded 17 compounds, including eleven phenylpropanoid glycosides (1–11), two flavonoids (12, 13), one lignan (14), and three phenolic acids (15–17) were isolated from the fresh whole plant of O. cernua. Their structures were identified by spectroscopic analyses and by comparison of their spectral data with those reported in the literature. This is the first report of isolation of compounds (6, 8, 9, 11, 14–16) from O. cernua and compounds (14, 15) from the family Orobanchaceae, respectively. Compound 14 was obtained from natural source for the first time, the chemotaxonomic significance of these compounds was summarized.     

Phenolic constituents from the roots of Rosa laevigata (Rosaceae)

Chemical investigation of the root of Rosa laevigata led to the isolation of sixteen phenolic compounds, including seven flavonoids (1–7), five condensed tannins (8–12), two stilbenes (13 and 14) and two benzoic acid derivatives (15 and 16). Their structures were identified as (+)-catechin (1), (+)-gallocatechin (2), (2R, 3S, 4S)-cis- leucocyanidin (3), (2R, 3S, 4S)-cis-leucofisetinidin (4), (2S, 3R, 4R)-cis- leucofisetinidin (5), dehydrodicatechin A (6), phloridzin (7), procyanidin B3 (8), fisetinidol-(4α, 8)-catechin (9), guibourtinidol- (4α, 8)-catechin (10), ent- isetinidol -(4α, 6)-catechin (11), fisetinidol-(4β, 8)-catechin (12), (Z)-3-methoxy-5-hydroxy- stilbene (13), (Z)-piceid (14), gallic acid (15) and 4-hydroxybenzoic acid- 4-O-β-D-glucopyranoside (16). Among them, compounds 3–7, 9–14, and 16 were isolated from R. laevigata for the first time, and compounds 3–7, 9, 10, 12–14 and 16 were reported for the first time from the genus Rosa. The chemotaxonomic significance of these compounds was summarized.     

Chemical constituents from Psychotria yunnanensis and its chemotaxonomic study

Phytochemical investigation on the aerial parts of Psychotria yunnanensis led to the isolation of four norisoprenoids (1–4), one monoterpenoid (5), and eleven phenolic compounds (6–16). To our knowledge, all compounds were isolated from this plant for the first time. Compounds 2–16 were reported for the first time from the genus Psychotria. The chemotaxonomic significances of these compounds were summarized.     

Phenolic derivatives from Garcinia multiflora Champion ex Bentham and their chemotaxonomic significance

A phytochemical investigation of the leaves and twigs of Garcinia multiflora Champion ex Bentham led to the isolation of eleven phenolic derivatives, including a new polycyclic polyprenylated acylphloroglucinol (PPAP, 1), five known PPAPs (2–6), three xanthones (7–9), a benzophenone (10), and a methyl phenyl acetate derivative (11). Their structures were established by extensive spectroscopic analysis, including HR-ESI-MS and NMR. Five compounds (1, 2, 4, 5, and 11) were first found in the genus Garcinia, of which compounds 1 and 11 were reported from the family Guttiferae for the first time. The chemotaxonomic significance of the isolated compounds was discussed. Furthermore, six PPAPs showed good cytotoxicities with IC₅₀ values ranging from 1.79 to 9.40 μM.     

Phenolic compounds and triterpenes from the roots of Vaccinium dunalianum Wight and their chemotaxonomic significance

Eight phenolic compounds, including two catechins (1 and 2), two proanthocyanidins (3 and 4), three lignans (5–7), and one phenol (8), were isolated from roots of Vaccinium dunalianum Wight (Ericaceae), together with two triterpenes (9 and 10). All of them were isolated from the title plant for the first time. Their chemical structures were established based on the extensive MS and NMR spectroscopic analysis. Compounds 6–10 acquired initially from the genus Vaccinium, showed some significances in chemotaxonomy.     

Secondary metabolites produced by an endophytic fungus Cordyceps ninchukispora from the seeds of Beilschmiedia erythrophloia Hayata

Four new amide derivatives, designated as cordycepiamides A–D (1–4), together with 14 known compounds (5–18), were isolated from the EtOAc-soluble fraction of the 95% EtOH extract of long-grain rice fermented with the endophytic fungus C. ninchukispora BCRC 31900, derived from the seeds of medicinal plant Beilschmiedia erythrophloia Hayata. Their structures were elucidated by means of spectroscopic and mass-spectrometric analyses, particularly 1D and 2D NMR spectroscopy as well as HRESIMS. All known isolates except 11, were isolated for the first time from this species. The antiinflammatory activities of selected isolated 10 compounds (1, 2, 4–6, 9–12, and 14) were evaluated as inhibitory activities against lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW264.7 cell lines. Compound 3→4 was shown to have modest anti-inflammatory effects through inhibition of NO production in LPS-stimulated RAW264.7 cells.     

A new phenolic acid from Zanthoxylum nitidum var. tomentosum (Rutaceae) and its chemotaxonomic significance

A new compound, nitomentosin (1), along with sixteen known compounds (2–17), were isolated from Zanthoxylum nitidum var. tomentosum (Rutaceae). The structure of compound 1 including absolute configurations was determined by detailed spectroscopic information (HRESIMS and NMR) and from the electronic circular dichroism (ECD) spectra. From the present investigation, compound 3 is a new natural compound although it has been reported previously as a synthetic substance, and compound 15 is found for the first time in a plant. All these compounds except 2, 5–10 and 12 were isolated from Z. nitidum for the first time. Furthermore, the chemotaxonomic significance of the isolated compounds is discussed.     

Pharmaceutically active secondary metabolites of marine actinobacteria

Marine actinobacteria are one of the most efficient groups of secondary metabolite producers and are very important from an industrial point of view. Many representatives of the order Actinomycetales are prolific producers of thousands of biologically active secondary metabolites. Actinobacteria from terrestrial sources have been studied and screened since the 1950s, for many important antibiotics, anticancer, antitumor and immunosuppressive agents. However, frequent rediscovery of the same compounds from the terrestrial actinobacteria has made them less attractive for screening programs in the recent years. At the same time, actinobacteria isolated from the marine environment have currently received considerable attention due to the structural diversity and unique biological activities of their secondary metabolites. They are efficient producers of new secondary metabolites that show a range of biological activities including antibacterial, antifungal, anticancer, antitumor, cytotoxic, cytostatic, anti-inflammatory, anti-parasitic, anti-malaria, antiviral, antioxidant, anti-angiogenesis, etc. In this review, an evaluation is made on the current status of research on marine actinobacteria yielding pharmaceutically active secondary metabolites. Bioactive compounds from marine actinobacteria possess distinct chemical structures that may form the basis for synthesis of new drugs that could be used to combat resistant pathogens. With the increasing advancement in science and technology, there would be a greater demand for new bioactive compounds synthesized by actinobacteria from various marine sources in future.     

Secondary metabolites from Saururus chinensis and their chemotaxonomic significance

Phytochemical investigation of the whole plants of Saururus chinensis resulted in the isolation of two sesquiterpenes (1 and 2), five lignans (3-7), one alkaloid (8) and two steroids (9 and 10). Among them, compound 3 has not been reported as a natural product before. Compounds 1, 2, 8 and 10 were firstly reported from the family Saururaceae. The possible biosynthesis pathway for sauchinone-like neolignans (6 and 11) was also firstly proposed. Furthermore, the chemotaxonomic significance of these compounds was summarized.     

Chemical constituents from the fruits of Phyllanthus emblica L.

Chemical investigation of the fruits of Phyllanthus emblica led to the isolation of one new aryltetralin-type lignan (1), along with twelve known polyphenols (2–13). Their structures were determined via extensive analyses of spectroscopic data and comparison with the reported literature values. Among them, polyphenols 1, 6, 7, and 10 were isolated from the family Euphorbiaceae for the first time. Furthermore, the chemotaxonomic significance of the isolates was also discussed.     

Evolution of secondary metabolites from an ecological and molecular phylogenetic perspective

Secondary metabolites, at least the major ones present in a plant, apparently function as defence (against herbivores, microbes, viruses or competing plants) and signal compounds (to attract pollinating or seed dispersing animals). They are thus important for the plant's survival and reproductive fitness. Secondary metabolites therefore represent adaptive characters that have been subjected to natural selection during evolution. Molecular phylogenies of the Fabaceae, Solanaceae and Lamiaceae were reconstructed and employed as a framework to map and to interpret the distribution of some major defence compounds that are typical for the respective plant families; quinolizidine alkaloids and non-protein amino acids for legumes; tropane and steroidal alkaloids for Solanaceae, and iridoids and essential oils for labiates. The distribution of the respective compounds appears to be almost mutually exclusive in the families studied, implying a strong phylogenetic and ecological component. However, on a closer look, remarkable exceptions can be observed, in that certain metabolites are absent (or present) in a given taxon, although all the neighbouring and ancestral taxa express (or do not express, respectively) the particular trait. It is argued that these patterns might reflect differential expression of the corresponding genes that have evolved earlier in plant evolution. The inconsistent secondary metabolite profiles mean that the systematic value of chemical characters becomes a matter of interpretation in the same way as traditional morphological markers. Thus, the distribution of secondary metabolites has some value for taxonomy but their occurrence apparently reflects adaptations and particular life strategies embedded in a given phylogenetic framework.     

Secondary metabolites from Ajania salicifolia and their chemotaxonomic significance

Forty-seven secondary metabolites were isolated from Ajania salicifolia (Mattf.) Poljak, including eight sesquiterpenoids, two diterpenoids, three triterpenoids, four steroids, three flavonoids, five coumarins, five lignans, nine phenylpropanoids, five other phenolic compounds, and three acetylenes. Their chemotaxonomic significance within the genus Ajania (the tribe Anthemideae) of the family Asteraceae is discussed.     

Coumarins and other components of Daphne oleoides Schreb. subsp. oleoides from Majella National Park

The present study reports about the phytochemical analysis of a sample of Daphne oleoides Schreb. subsp. oleoides (family Thymelaeaceae) collected from the Majella National Park. Twenty components, belonging to different classes of natural products, have been identified by means of spectroscopic and spectrometric techniques: [monomeric (4), bis- (5, 7–10, 20) and trimeric coumarins (11), including aglycones and glycosides, coumarinolignoid (6); flavonoids (16–19); glycosidic furolignans (14, 15), glucosidic phenylpropanoids (12, 13), cyclic tetrapyrrole derivatives (2, 3), unsaturated triglyceride (1)]. Besides the chemosystematic markers of the genus (4–10, 12, 14–18, 20) several other components were identified for the first time in the species (17, 20) and/or in the Daphne genus (1–3, 13, 19). The observed composition was discussed from the chemotaxonomic standpoint and compared with those recognized from a Sardinian accession. It was observed a pronounced difference in the two metabolites patterns, most probably attributable to geographic isolation of the studied populations and, in some extent, also by the different environmental conditions, evidencing a possible tendency of D. oleoides to the infraspecific chemovariability. Considering the wide traditional uses of Daphne spp. in ethnomedicine of several countries, also the pharmacologic potential of the identified secondary metabolites is discussed.