Terpene and lignan glycosides from the twigs and leaves of an endangered conifer, Cathaya argyrophylla

Polyphenols, Antioxidants, and Wound Healing of Lecythis pisonis Seed Coats

To better use the Lecythis pisonis Cambess. biomass, this study investigates whether Sapucaia seed coats present wound healing properties. We analyzed the antibacterial, antioxidant, and wound healing-promoting potentials, plus cytotoxicity and stimulation of vascular endothelial growth factor-A. The chemical composition was analyzed by positive ion mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. A total of 19 compounds were identified, such as proanthocyanidin A1, procyanidins A1, B2, and C1, epigallocatechin, and kaempferol (p-coumaroyl) glycoside. Potent antioxidant strength/index was verified for 2,2-diphenyl-1-picrylhydrazyl radical (IC50 = 0.99 µg/mL) and ferric reducing antioxidant power (IC50 = 1.09 µg/mL). The extract did not present cytotoxicity and promoted significant cell migration and/or proliferation of fibroblasts (p < 0.05). Vascular endothelial growth factor-A was stimulated dose-dependently at 6 µg/mL (167.13 ± 8.30 pg/mL), 12.5 µg/mL (210.3 ± 14.2 pg/mL), and 25 µg/mL (411.6 ± 29.4 pg/mL). Platelet-derived growth factor (PDGF) (0.002 µg/mL) was stimulated at 215.98 pg/mL. Staphylococcus aureus was susceptible to the extract, with a minimum inhibitory concentration of 31.25 µg/mL. The identified compounds benefit the antioxidant activity, promoting hemostasis for the wound healing process, indicating that this extract has the potential for use in dermatological cosmetics.

Neurotrophic neolignans of Pinus koraiensis twigs

Four undescribed neolignan analogs, together with eight known compounds, were isolated from the twigs of Pinus koraiensis (Korean pine). The chemical structure of the isolated compounds was determined through extensive spectroscopic analysis and chemical method. Their relative and absolute configurations were assigned through a well-established empirical rule and electronic circular dichroism (ECD) analysis, respectively. Four compounds (3 and 9-11) at 20 μM concentration showed significant neurotrophic effect by inducing nerve growth factor (NGF) secretion in C6 cells with the stimulation levels a range of 140.82 ± 4.62% to 160.04 ± 11.04%. Additionally, the result indicated that the glycosylation of neolignan led to an improvement in neurotrophic activity compared to their aglycone form. A compound (7) inhibited nitric oxide production with an IC50 value of 31.74 μM in LPS-activated BV2 cells.

Recent progress on anti-Candida natural products

Candida is an intractable life-threatening pathogen. Candida infection is extremely difficult to eradicate, and thus is the major cause of morbidity and mortality in immunocompromised individuals. Morevover, the rapid spread of drug-resistant fungi has led to significant decreases in the therapeutic effects of clinical drugs. New anti-Candida agents are urgently needed to solve the complicated medical problem. Natural products with intricate structures have attracted great attention of researchers who make every endeavor to discover leading compounds for antifungal agents. Their novel mechanisms and diverse modes of action expand the variety of fungistatic agents and reduce the emergence of drug resistance. In recent decades, considerable effort has been devoted to finding unique antifungal agents from nature and revealing their unusual mechanisms, which results in important progress on the development of new antifungals, such as the novel cell wall inhibitors YW3548 and SCY-078 which are being tested in clinical trials. This review will present a brief summary on the landscape of anti-Candida natural products within the last decade. We will also discuss in-depth the research progress on diverse natural fungistatic agents along with their novel mechanisms.

Chemical constituents and aldose reductase inhibitory activities of Betula alba bark and leaves

Systematic phytochemical investigation of the bark and leaves of Betula alba was independently conducted. A new cyclic diarylheptanoid glucoside (1), five diarylheptanoids (2-6), a phenylethanoid (7), a methyl salicylate glycoside (8), a dihydrobenzofuran glucoside (9), an arylbutanoid glycoside (10), two lignan glycosides (11 and 12), a flavanone glucoside (13), and a triterpene (14) were isolated from the bark of B. alba. On the other hand, two cyclic diarylheptanoids (15 and 16), five flavonoids (17-21), a phenylpropanoid (22), a phenylbutanoid glucoside (23), and a monoterpene glucoside (24) were obtained from the leaves of B. alba. The structures of the isolated compounds (1-24) were identified on the basis of one- and two-dimensional NMR spectroscopic data. Compounds 1-24 were subsequently examined for aldose reductase (AR) inhibitory activity. Compounds 14 and 17-20 moderately inhibited AR activity with IC₅₀ values ranging from 6.6 to 34 µM.

A new coumarin isolated from the roots of Heracleum dissectum Ledeb

A new coumarin named (9 R, 10 R)-9, 10-dihydro-10-hydroxy-9-methoxy-bergapten (1) and 13 known compounds (2-14) were isolated from the roots of Heracleum dissectum Ledeb., in which compounds (2-13) were obtained from H. dissectum for the first time. Their structures were illuminated by HR-ESI MS, 1 D and 2 D NMR, optical rotation and comparison with literatures. All compounds were evaluated against hepatocellular carcinoma HepG2 cell lines and the results showed that candinol C (8) had moderate cytotoxic activity against HepG2 cells with IC₅₀ value at 57.6 ± 1.1 µM.

Novel biotechnological glucosylation of high-impact aroma chemicals, 3(2H)- and 2(5H)-furanones

Glucosyltransferases are versatile biocatalysts to chemically modify small molecules and thus enhance their water solubility and structural stability. Although the genomes of all organisms harbor a multitude of glucosyltransferase genes, their functional characterization is hampered by the lack of high-throughput in-vivo systems to rapidly test the versatility of the encoded proteins. We have developed and applied a high-throughput whole cell biotransformation system to screen a plant glucosyltransferase library. As proof of principle, we identified 25, 24, 15, and 18 biocatalysts transferring D-glucose to sotolone, maple furanone, furaneol and homofuraneol, four highly appreciated flavor compounds, respectively. Although these 3(2H)- and 2(5H)-furanones have extremely low odor thresholds their glucosides were odorless. Upscaling of the biotechnological process yielded titers of 5.3 and 7.2 g/L for the new to nature β-D-glucopyranosides of sotolone and maple furanone, respectively. Consequently, plant glucosyltransferase show stunning catalytic activities, which enable the economical production of novel and unexplored chemicals with exciting new functionalities by whole-cell biotransformation.

A new byciclic monoterpene glucoside and a new biflavone from the male reproduction organs of Wollemia nobilis

In this work, the fifth part of an ongoing phytochemical study on Wollemia nobilis was reported. The attention was now focused on the male reproduction organs of which the content in both primary and secondary metabolites was analyzed. Twenty compounds, belonging to seven different classes of natural compounds, were identified from the ethanolic extract by means of Column Chromatography and NMR and MS Spectroscopy. They all represent new compounds for the studied organ whereas some of them are also new constituents of the genus or even previously undescribed phytochemicals. Their presence was able to display a general overview of these organs from the phytochemical standpoint and to provide more elements in confirmation with the current botanical classification of the species. Moreover, they add a further experimental evidence of the tendency of this species to accumulate different metabolites in different organs. This characteristic as well as the occurrence of several compounds with added value, make this plant a possible candidate for large scale cultivation with extractive purposes to obtain useful phytochemicals for botanicals and pharmaceutical fields. Moreover, they offer the opportunity to develop an additional method of conservation and protection for this endangered and very rare species.

Two new phenolic glycosides isolated from Ginkgo seeds

Two new phenolic glycosides, 7S, 8R-urolignoside-9'-O-β-D-glucoside (1) and scrophenoside G (2), were isolated and identified from the seeds of Ginkgo biloba L., a famous traditional medicine and functional food around the world. Their structures were elucidated by spectroscopic methods (1D and 2D NMR, HR-ESI-MS, and CD), and the comparisons of spectroscopic data with the reported values in the literature.

Lignan Glycosides and Flavonoid Glycosides from the Aerial Portion of Lespedeza cuneata and Their Biological Evaluations

Lespedeza cuneata (Fabaceae), known as Chinese bushclover, has been used in traditional medicines for the treatment of diseases including diabetes, hematuria, and insomnia. As part of a continuing search for bioactive constituents from Korean medicinal plant sources, phytochemical analysis of the aerial portion of L. cuneata led to the isolation of two new lignan glycosides (1,2) along with three known lignan glycosides (3–7) and nine known flavonoid glycosides (8–14). Numerous analysis techniques, including 1D and 2D NMR spectroscopy, CD spectroscopy, HR-MS, and chemical reactions, were utilized for structural elucidation of the new compounds (1,2). The isolated compounds were evaluated for their applicability in medicinal use using cell-based assays. Compounds 1 and 4–6 exhibited weak cytotoxicity against four human breast cancer cell lines (Bt549, MCF7, MDA-MB-231, and HCC70) (IC₅₀ < 30.0 μM). However, none of the isolated compounds showed significant antiviral activity against PR8, HRV1B, or CVB3. In addition, compound 10 produced fewer lipid droplets in Oil Red O staining of mouse mesenchymal stem cells compared to the untreated negative control without altering the amount of alkaline phosphatase staining.

Terpenoids and More Polar Compounds from the Male Cones of Wollemia nobilis

The analysis of metabolites contained in the male cones of Wollemia nobilis was investigated for the first time in this study. Several diterpenoids of chemosystematic relevance were recognized for the first time from the genus and/or from the Araucariaceae family, namely isocupressic acid (1), acetyl-isocupressic acid (2), methyl (E)-communate (3) and sandaracopimaric acid (4). All these terpenoids are also endowed with interesting biological activities and may play a primary role in the self defence toward herbivores. The presence of a new norlabdane (norlabda-8(16)-12-dien-14,17-diol) trivially named as wollemol (5) was also recognized. Norditerpenes are scarcely distributed in Plant Kingdom and in particular in Gymnosperms and this aspect was discussed. The structure of 5 was determined by extensive NMR analysis employing mono- and bidimensional experiments. The 7-4‴-dimethoxyagathisflavone (6), a biflavonoid already recognized in Araucariaceae and W. nobilis, was also isolated from male cones together with shikimic acid (7), a biogenetic precursor of polyphenolic compounds, besides carbohydrates such as glucose (8) and saccharose (9), and arginine (10) a quite common amino acid.

New polyacetylenes from Echinophora cinerea (Boiss.) Hedge et Lamond

Echinophora cinerea aerial parts are used in folk medicine to cure gastric diseases and as a food seasoning in cheese and yogurt. Besides several pharmacological effects have been assigned to Echinophora spp., there is no phytochemical investigation on this genus other than our previous publication on flavonoids. An acetone extract of E. cinerea afforded three new (1-3) polyacetylenes, one rare monoterpenoid glycoside as verbenone-5-O-β-D-glycopyranoside (4) and one prenylated coumarin as osthol (5). The structures of all new compounds were elucidated using modern spectroscopic methods, including 2D NMR and mass analyses. The potency of the compounds to induce cell death was determined on SKNMC, PC3 and MCF-7 cell lines using MTT method in which compounds 1 and 2 showed moderate cytotoxic effects, especially against PC3 cells.

Polyphenolic glycosides isolated from Pogostemon cablin (Blanco) Benth. as novel influenza neuraminidase inhibitors

BACKGROUND

Influenza is historically an ancient disease that causes annual epidemics and, at irregular intervals, pandemics. At present, the first-line drugs (oseltamivir and zanamivir) don't seem to be optimistic due to the spontaneously arising and spreading of oseltamivir resistance among influenza virus. Pogostemon cablin (Blanco) Benth. (P. cablin) is an important traditional Chinese medicine herb that has been widely used for treatment on common cold, nausea and fever. In our previous study, we have identified an extract derived from P. cablin as a novel selective neuraminidase (NA) inhibitor.

RESULTS

A series of polyphenolic compounds were isolated from P. cablin for their potential ability to inhibit neuraminidase of influenza A virus. Two new octaketides (1, 2), together with other twenty compounds were isolated from P. cablin. These compounds showed better inhibitory activity against NA. The significant potent compounds of this series were compounds 2 (IC50 = 3.87 ± 0.19 μ mol/ml), 11, 12, 14, 15, 19 and 20 (IC50 was in 2.12 to 3.87 μ mol/ml), which were about fourfold to doubled less potent than zanamivir and could be used to design novel influenza NA inhibitors, especially compound 2, that exhibit increased activity based on these compounds. With the help of molecular docking, we had a preliminary understanding of the mechanism of the two new compounds (1-2)' NA inhibitory activity.

CONCLUSIONS

Fractions 6 and polyphenolic compounds isolated from fractions 6 showed higher NA inhibition than that of the initial plant exacts. The findings of this study indicate that polyphenolic compounds and fractions 6 derived from P. cablin are potential NA inhibitors. This work is one of the evidence that P. cablin has better inhibitory activity against influenza, which not only enriches the compound library of P. cablin, but also facilitates further development and promises its therapeutic potential for the rising challenge of influenza diseases.

Two New Cinnamyl Isovalerate Derivatives from Sabina gaussenii

Chemical investigation of the 90% acetone extract of the branches and leaves of Sabina gaussenii led to the isolation of two new cinnamyl isovalerate derivatives (1–2) and eighteen known compounds (3–20). Their structures were determined mainly by means of MS, 1D- and 2D-NMR data, and this is the first time these compounds have been reported from this plant. The biological activity test results indicated that the 90% acetone extract showed cytotoxicity against the human lung adenocarcinoma (A549) cell line (IC₅₀ = 0.98 ± 0.1 μg/mL), compound 6 showed cytotoxicities against human cervical carcinoma (HeLa) (IC₅₀ = 0.4 ± 0.1 μM ) and human gastric carcinoma (BGC-823) (IC₅₀ = 0.9 ± 0.2 μM) cancer cell lines, and compound 19 showed cytotoxicities against HeLa (IC₅₀ = 1.5 ± 0.4 μM), BGC-823 (IC₅₀ = 7.0 ± 0.8 μM ), and A549 (IC₅₀ = 10.6 ± 1.5 μM ) cancer cell lines.

Lignan Glycosides from the Twigs of Chaenomeles sinensis and Their Biological Activities

Phytochemical investigation of the twigs of Chaenomeles sinensis led to the isolation and identification of six new lignan glycosides, chaenomiside A-F (1-6), along with five known ones (7-11). Their chemical structures were determined by spectroscopic methods, including NMR, MS, ECD, and GC/MS analyses. All the isolated compounds (1-11) were tested for their inhibitory effects on nitric oxide (NO) production in lipopolysaccharide-activated murine microglial cells and the secretion of nerve growth factor (NGF) in a C6 rat glioma cell line. Compound 6 significantly reduced NO levels in the murine microglia BV2 cells with an IC50 value of 21.3 μM, and compounds 1, 3, and 6 were potent stimulants of NGF release with stimulation levels of 151.74 ± 6.77%, 144.31 ± 7.49%, and 167.61 ± 18.5%, respectively.

Isolation and purification of schisandrol A from the stems of Schisandra chinensis and cytotoxicity against human hepatocarcinoma cell lines

BACKGROUND

Schisandrol A, a lignan with anticancer effects, is one of the representative components that identifies Schisandra chinensis.

OBJECTIVE

A method for purifying schisandrol A from the stems of S. chinensis was established using an octadecylsilyl (ODS) column combined with preparative high-performance liquid chromatography (HPLC).

MATERIALS AND METHODS

Crude extracts obtained from the stems of S. chinensis using 70% ethanol were separated on an AB-8 macroporous resin column and then eluted with a graded ethanol series. After 70% methanol was used in an ODS column separation, preparative HPLC was used for subsequent purification. The structure was identified by electrospray ionization-mass spectrometry, (1)H-nuclear magnetic resonance, and (13)C-nuclear magnetic resonance. HepG2 and Bel-7402 hepatocellular carcinoma cell lines were used for toxicological evaluation.

RESULTS

21.4 mg of schisandrol A with a purity of 95.2% were collected. The cytotoxicity of the ODS-purified sample and schisandrol A were significantly stronger than that of a resin-purified sample.

CONCLUSION

Schisandrol A was successfully extracted from the stems of S. chinensis and separated with an ODS column combined with preparative HPLC. The samples obtained during the purification process showed different levels of cytotoxicity on the HepG2 and Bel-7402 hepatocellular carcinoma cell lines.

Bioactive lignans from the trunk of Abies holophylla

Six new lignans (1-6) were isolated from the trunk of Abies holophylla MAXIM, together with 11 known lignans (7-17). The structures of 1-7 were elucidated by spectroscopic methods, acid hydrolysis, and use of the modified Mosher's method. The effects of the isolates on nerve growth factor induction in a C6 rat glioma cell line were evaluated. Compounds 6, 7, and 13 showed significant induction of nerve growth factor secretion at concentrations of 10 μM. Compounds 1, 5, 6, and 16 showed moderate inhibitory effects on nitric oxide production in lipopolysaccharide-activated BV-2 cells (IC50 28.5-36.4 μM).