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.

Diarylpropanes from Horsfieldia kingii.

Three new diarylpropanes (1-3), including two diarylpropane glycosides, and three known ones, were isolated from 70% aqueous acetone extract of the twigs and leaves of Horsfieldia kingii. Their structures were elucidated by spectroscopic analysis. Bioactive evaluation of inhibition on DDC enzyme assay showed that the new compounds were inactive.

Aromatic compounds from Endocomia macrocoma.

Twenty-seven compounds, including a new diarypropane and two new lignans were isolated from the twigs and leaves of Endocomia macrocoma. Their structures were elucidated by spectroscopic analysis. Cytotoxicity evaluation of the new compounds against five human tumor lines showed no inhibitory effects.[Formula: see text].

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.

Horisfieldones A and B, Two Aromatic Ring-Contracted Dimeric Diarylpropanes with Human DOPA Decarboxylase Inhibitory Activity from Horsfieldia kingii.

Horisfieldones A (1) and B (2), two dimeric diarylpropanes featuring an unprecedentedly aromatic ring-contracted framework, were isolated from Horsfieldia kingii. Their structures and absolute configurations were determined by the inspection of extensive spectroscopic data and electronic circular dichroism calculations. Molecular modeling analysis, in vitro enzyme-based bioassays, and structure-activity relationship analysis of these isolates revealed that (+)-1 (IC50 = 35.1 ± 3.9 µM, SI > 11.4) could present a new class of human DOPA decarboxylase inhibitor.

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.

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 lignans from Horsfieldia kingii.

Two new dibenzylbutyrolactol lignans and three known dibenzylbutyrolactone lignans were isolated from the twigs and leaves of Horsfieldia kingii. Their structures were elucidated by spectroscopic analysis. Cytotoxicity evaluation of these compounds against five human tumour lines showed no inhibitory effects.

A new dimeric diarylpropane from Horsfieldia tetratepala.

Five compounds, including a new dimeric diarylpropane, were isolated from the petroleum ether extract of the twigs and leaves of Horsfieldia tetratepala. The structures of these compounds were elucidated by spectroscopic analysis. Moreover, the antiproliferative activities of these compounds were tested on cancer cell lines, but none is active.

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.

Novel 9, 10-dihydrophenanthrene derivatives from Eria bambusifolia with cytotoxicity aganist human cancer cells in vitro.

The present study was designed to identify bioactive compounds similar to those isolated from Dendrobium genus from its relative specie Eria bambusifolia. Compounds 1-10 were isolated and purified using silica gel, MCI CHP-20 gel, Sephadex LH-20, and Lichroprep RP-18 chromatography methods. Their structures were elucidated by means of extensive spectroscopic analyses. The cytotoxicity of these compounds against five human cancer cell lines was tested. Erathrins A and B (1 and 2) were new compounds, and compound 1 represented a novel carbon framework having a phenanthrene-phenylpropane unit with a dioxane moiety. Moreover, compound 1 showed selective cytotoxic activity against HL-60 cells (IC50 = 14.50 µmol·L(-1)). These results provided a basis for future development of these agents as anticancer lead compounds.

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.

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.

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.