Immunosuppressive diarylpropane dimer and spirocyclic-monomers from Horsfieldia kingii.

Horsfiequinone G (1), a dimeric diarylpropane featuring an unprecedentedly oxo-6/7/6 fused ring system, a new flavane, horsfielenide F (2), three naturally occurring spirocyclic monomers containing all-carbon quaternary centers, horspirotone A (3), horspirotone B (4), and methyl spirobroussonin B (5), along with horsfiequinone A (6) were isolated from Horsfieldia kingii. Their structures and absolute configurations were determined by the inspection of extensive spectroscopic data and electronic circular dichroism (ECD) calculations. Biological evaluations of these isolates revealed that compounds 1 - 3 and 5 - 6 exhibited specifically immunosuppressive activities against Con A-induced T lymphocytes with IC50 values ranging from 2.07 to 12.34 µM (selectivity indices = 2.3-25.2). Compound 1 also suppressed the secretion of inflammatory factors like IL-1ß and IL-6 in RAW264.7 cells which could present a new class of nonsteroidal anti-inflammatory agent. Finally, the primary structure-activity relationship (SAR) was also discussed.

Immunosuppressive Bibenzyl-phenylpropane Hybrids from Dendrobium devonianum.

Two new bibenzyl-phenylpropane hybrids, dendrophenols A and B (1 and 2), along with nine known bibenzyls, were isolated from the aerial part of Dendrobium devonianum Paxt. Their structures were determined by extensive spectroscopic methods and methylation. Bioassays revealed that compounds 1-9 were specifically immunosuppressive to T lymphocytes with IC50 values ranging from 0.41 to 9.4 µM, of which compounds 1 (IC50 =1.62 µM) and 2 (IC50 =0.41 µM) were promising immunosuppressive agents for T lymphocytes with the selectivity indices of 19.9 and 79.5, respectively.

Isopentenylated Bibenzyls and Phenolic Compounds from Dendrobium chrysotoxum Lindl.

Two new isopentenyl bibenzyls, denchrysotonols A and B (1-2), along with 26 known phenolic compounds, were isolated from the stems of cultivated Dendrobium chrysotoxum Lindl. Their chemical structures were clearly elucidated by extensive spectroscopic analysis. Biological evaluation of isolated compounds revealed that phenanthrenes (14, 16-17, 20, and 22) and fluorenone 25 exhibited anti-inflammatory activities which inhibited nitric oxide (NO) production in LPS-activated RAW264.7 macrophages with the IC50 values ranging from 9.4 to 32.5 µM. Moreover, bibenzyls (1-2 and 7) showed good anti-proliferative activities against triple-negative breast cancer (TNBC) cells (HCC1806, MDA-MB-231, and MB-MB-468) with the IC50 values ranging from 8.1 to 18.6 µM, of which 1 and 2 seemed preferentially inhibit MDA-MB-231 cells.

Synthesis and evaluation of inhibitory activity in vitro of dihydrostilbenes against human neutrophil elastases.

Twelve dihydrostilbenes (including five new analogues) were prepared by the Witting-Hornor reaction from appropriate aromatic aldehydes and phosphonate esters, followed by hydrogenation in five steps. The in vitro inhibition activity against human neutrophil elastase (HNE) of these dihydrostilbenes was evaluated, and three 1,2-dihydroxylated dihydrostilbenes (6b, 6j, and 6l) exhibited stronger inhibitory activity against HNE than other analogues.

Two new picrotoxane-type sesquiterpenoid lactones from Dendrobium williamsonii.

Two new picrotoxane-type sesquiterpenoid lactones, dendrowillins A (1) and B (2), together with five known sesquiterpenoids, (-)-picrotin (3), α-dihydropicrotoxinin (4), dendronobilin B (5), amoenin (6), and (-)-10ß,13,14-trihydroxyalloaromadendrane (7), were isolated from the whole plants of Dendrobium williamsonii. Their structures were elucidated by means of extensive spectroscopic analysis.

Two new phenylpropanoid esters from Bulbophyllum retusiusculum.

Two new phenylpropanoid esters bobulretulates A (1) and B (2), together with eleven known compounds, were isolated from the whole plants of Bulbophyllum retusiusculum. Their structures were elucidated by means of extensive spectroscopic analysis.

A new 5(6→7)abeo-sterol from Podocarpus fleuryi.

A new 5(6→7)abeo-sterol, podosterol (1), together with 20 known compounds, were isolated from the leaves of Podocarpus fleuryi. Their structures were elucidated by means of extensive spectroscopic analysis. Podosterol was assessed for its cytotoxicity against five human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW-480), and the result showed that it had no activity.

Chemical Constituents of Plants from the Genus Phlegmariurus.

Phlegmariurus is a genus of ca. 200 species in the family Huperziaceae. Up to now, six species of the Phlegmariurus genus have been chemically investigated, and 89 compounds, including Lycopodium alkaloids possessing diverse structures and serratane-type triterpenes, have been isolated. These compounds show potent bioactivities, such as acetylcholinesterase inhibitory and cytotoxic activities.

Chemical Constituents of Plants from the Genus Ixora.

Ixora is a genus of ca. 400 species in the family Rubiaceae. Since the 1940s, eighty-one compounds including phenolics, peptides, terpenoids, and sterols have been isolated from six species of the genus Ixora. Pharmacological studies have shown that these compounds and extracts from the Ixora genus have extensive activities, such as antitumor, chemoprotective, and antioxidant activities. In this review, we summarize the phytochemical progress and list the compounds isolated from the genus Ixora. The biological activities of this genus are also covered.

Chemical Constituents of Plants from the Genus Psychotria.

Psychotria is a genus of ca. 1500 species in the family Rubiaceae. Up to now, 41 species of the Psychotria genus have been chemically investigated, and 159 compounds, including alkaloids of indole, quinoline and benzoquinolizidine type, terpenoids, steroids, phenolics and aliphatic compounds have been isolated. These compounds show potent bioactivities, such as antimicrobial, antiviral, and antiparasitic activities.

Eruberin A, a Natural Flavanol Glycoside, Exerts Anti-Fibrotic Action on Pancreatic Stellate Cells.

BACKGROUND: Eruberin A (2, 3-dehydroflavonoid), a flavanol glycoside isolated from Pronephrium penangianum, has been used as a blood-nourishing folk medicine for centuries; however, it indeed possesses a variety of other health-promoting benefits including anti-fibrotic bioactivity. Activation of pancreatic stellate cells (PSCs) is the key initiating step in pancreatic fibrosis, which is a characteristic feature associated with chronic pancreatitis and pancreatic adenocarcinoma. METHODS: The anti-fibrotic effect of eruberin A and the underlying mechanisms of its anti-fibrotic action in LTC-14 cells, which retained essential characteristics and morphological features of primary PSCs, were examined by means of real-time polymerase chain reactions, Western blotting and immunostaining. RESULTS: The application of eruberin A (20 µg/ml) effectively inhibited the expression levels of fibrotic mediators namely alpha-smooth muscle actin, fibronectin and type I-collagen, so as the sonic hedgehog signaling pathway components post transforming growth factor-beta (5 ng/ml) stimulation. Eruberin A treatment also led to a notable decrease in the activation of nuclear factor-kappaB (NF-κB) and the phosphorylation of phosphoinositide 3-kinase (PI3K)/serine-threonine kinase (AKT). CONCLUSION: Our results demonstrated that eruberin A significantly suppressed the expression levels of fibrotic mediators in PSCs, and we suggest that its anti-fibrotic mechanism was associated with an attenuation of the PI3K/AKT/NF-κB signaling pathway.

Horsfiequinones A-F, dimeric diarylpropanoids from Horsfieldia tetratepala.

A new diarylpropanoid, horsfiequinone A (1), and five new dimeric diarylpropanoids with 1,4-p-benzoquinone residue, horsfiequinones B-F (2-6), along with a known compound, combrequinone B (7), were isolated from Horsfieldia tetratepala. Their structures were elucidated by means of spectroscopic analysis. Horsfiequinones B-F (2-6), isolated as enantiomer mixtures with unequal proportions, were verified by analysis on a chiral OD-H HPLC column. Cytotoxicity evaluation against five human tumor lines showed selective inhibitory effects on HL-60 for several compounds tested with IC50 values ranging from 3.18 ± 0.67 to 6.61 ± 0.08 µM.

Microbiological transformation of the triterpene nigranoic acid by the freshwater fungus Dictyosporium heptasporum.

The microbiological transformation of the triterpene nigranoic acid (3,4-secocycloarta-4(28),24(Z)-diene-3,26-dioic acid) (1) to 3,4-secocycloarta-4(28),17(20),24(Z)-triene-7ß-hydroxy-16ß,26-lactone-3-oic acid (2) and 3,4-secocycloarta-4(28),17(20)(Z),24(Z)-triene-7ß-hydroxy-16ß-methoxy-3,26-dioic acid (3) by the freshwater fungus Dictyosporium heptasporum YMF1.01213 has been demonstrated. The structures of the biotransformation products were determined by spectroscopic and MS analyses. Compound 2, characterized by the presence of a formed C-16/C-26 ester bridge, provided a novel nine-membered lactone ring structural skeleton for 3,4-secocycloartane triterpenoid derivatives. In addition, Compounds 1-3 exhibited weak anti-HIV activity in vitro. Compounds 2 and 3 were reported for the first time as natural product derivatives.

[Study on distributed patterns of scoparone and ayapin in Dendrobium species from Yunnan].

An HPLC method for determination of scoparone and ayapin was established for investigating the distributed patterns of scoparone and ayapin in 37 species of Dendrobium. The contents of scoparone and ayapin in varied collected samples were determined by the established HPLC method. The pseudo-bulbs sampled were collected according to different growth age of D. thyrsiflorum. The results showed that the contents of scoparone and ayapin were much differently distributed in species of Dendrobium. Only D. thyrsiflorum and D. densfilorum contained both scoparone and ayapin, the content decreased with the growth age. A fewer amount of ayapin was tested in D. loddigesii from Wenshan. The scoparone and ayapin were not determined in the rest species of Dendrobium. The method was concise, sensitive, accurate and reproducible. It could be applied to assay scoparone and ayapin in populations of herbal Dendrobium.

Experimental investigation and quantitative prediction in interference-fit size of CFRP riveted joints under a transversal ultrasonic vibration-assisted riveting.

In this study, a transversal ultrasonic vibration-assisted riveting (TUVAR) process was developed to improve the uniformity of CFRP riveted lap joint interference-fit size, which provided a possibility for the quantization of riveted joint interference-fit sizes. The relationship between the process parameters of vibration amplitude, vibration duration, and roughness with interference-fit sizes by algorithms, through the minimum coefficient variance of interference-fit size (ICV-min) to confirm the riveting process parameters of the quantized average interference-fit sizes (IA). The experimental verification results showed that the mean absolute percentage error of measured IA and predicted IA is less than 10%. Furthermore, the tensile tests were carried out to investigate the effect of interference-fit size {1.4%, 1.6%, 1.8%, and 2.0%} on mechanical performances of CFRP riveted lap joints by TUVAR, and the tensile strength presents first-up then down with the interference-fit size increase, the maximum ultimate tensile strength is the riveted lap joint with the interference-fit size of 2.0%. Hence, the quantitative optimization method can well predict the riveting process parameters corresponding to the most uniform interference-fit size.

Compounds from Kadsura angustifolia with anti-HIV activity.

Four new cycloartane triterpenoids, angustific acid A (1), angustific acid B (2), angustifodilactone A (3) and angustifodilactone B (4) were isolated from the branches of Kadsura angustifolia together with six known compounds, micranoic acid B (5), nigranoic acid (6), schisandrin (7), schisantherin D (8), interiotherin B (9), schisantherin B (10). Their structures were established on the basis of extensive spectroscopic data analyses and comparison with spectroscopic data reported. Compound 1, characterized by the presence of a C-16/C-17, C-20/C-21 conjugated diene and a C-1/C-7 ester bridge formed in rings A and B, provided a novel structural skeleton for 3,4-secocycloartane triterpenoid derivatives. In addition, the anti-HIV activities of these compounds were determined in infected C8166 cells, and it was found that angustific acid A (1) exhibited the most potent anti-HIV activity with an EC(50) value of 6.1 µg/mL and a therapeutic index of more than 32.8.

Bioactive compounds from the fern Lepisorus contortus.

Phytochemical investigation of the whole plant of Lepisorus contortus (Christ) Ching led to the isolation of five new phenylethanoid glycosides (1-5), each containing a caffeoyl group, a new flavonoid glycoside (10), and 14 known compounds (6-9 and 11-15, syringic acid, vanillic acid, phloretic acid, diplopterol, and ß-sitosterol). This is the first report of phenylethanoid glycosides from the family Polypodiaceae. Compounds 1-15 were evaluated for their cancer chemopreventive potential based on their ability to inhibit tumor necrosis factor alpha (TNF-α)-induced NF-κB activity, nitric oxide (NO) production, and aromatase, quinone reductase 2 (QR-2), and COX-1/-2 activities. Quercetin-3-O-ß-d-glucoside (15) demonstrated inhibition against QR2 with an IC(50) value of 3.84 µM, which confirmed kaempferol/quercetin glycosides as the active compounds to inhibit QR2. The compound also demonstrated NF-κB activity with an IC(50) value of 33.6 µM. In addition, compounds 1, 2, 4, and 6 showed aromatase activity with IC(50) values of 30.7, 32.3, 26.8, and 35.3 µM, respectively.

Five new diarylpropan-1-ols from Combretum yunnanense.

Five new 1,3-diarylpropan-1-ols, combretol A-E (1- 5), together with one known coumarin (6) and ten known triterpenes (7-16), were isolated from Combretum yunnanense. Their structures were determined by spectroscopic investigation, including ¹H and ¹³C NMR, NOESY, HSQC, HMBC, and HRESIMS analyses. This is the first report on the occurrence of 1,3-diarylpropan-1-ols and coumarin in the Combretum genus including C. yunnanense. Also, to the best of our knowledge, 1,3-diarylpropan-1-ols are rare in nature.

New chalcone and dimeric chalcones with 1,4-p-benzoquinone residue from Combretum yunnanense.

New chalcone and dimeric chalcones with 1,4- P-benzoquinone residue, combrequinone A (1), combrequinone B (2), and combrequinone C (3), along with three known compounds (4-6), were isolated from the ethanolic extract of the stems and leaves of Combretum yunnanense, and their structures were determined by spectroscopic analysis. Compounds 1-3 were evaluated for in vitro cytotoxicity against five human cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7, and SW480. Compounds 1, 2 and 3 were found to be most potent against HL-60 acute leukemia cells, with IC50 values of 4.63, 4.07, and 1.26 µM, respectively.

Cytotoxic lignans from Cryptocarya impressinervia.

Chemical investigation of the twigs of Cryptocarya impressinervia yielded 23 known compounds including 8 lignans, 3 phenylpropionates, 1 xanthone, 3 flavonoids, 1 phenylpropanoid, 1 substitued phenol, 1 triterpenoid, 3 sterols and 2 aliphatic compounds. All the compounds was isolated from C. impressinervia for the first time. 9,9'-O-Di-feruloyl-(-)-secoisolariciresinol (1) displayed significant cytotoxic activities on five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW-480), with IC50 values of 3.58, 4.55, 6.39, 5.09 and 4.80 µM, respectively. Rhusemialin A (2) showed significant activity against HL-60 with IC50 of 3.69 µM. Dihydrosinapyl ferulate (3) displayed moderate cytotoxic activities against five tested human cancer cell lines. To the best of our knowledge, this is the first report on the constituents of C. impressinervia and cytotoxic activities of compounds 1-3 on the tested cancer cell lines.