Proposal for the classification of sinomenine alkaloids.

The chemical structure of sinoacutine is formed by a phenanthrene nucleus and an ethylamine bridge. Because it has a similar parent structure to morphine, it is subdivided into morphinane. At present, all reports have pointed out that the basic skeleton of morphine alkaloids is salutaridine (the isomer of sinoacutine), which is generated by the phenol coupling reaction of (R)-reticuline. This study shows that the biosynthetic precursors of sinoacutine and salutaridine are different. In this paper, the sinoacutine synthetase (SinSyn) gene was cloned from Sinomenium acutum and expressed SinSyn protein. Sinoacutine was produced by SinSyn catalyzed (S)-reticuline, according to the results of enzyme-catalyzed experiments. The optical activity, nuclear magnetic resonance, and mass spectrum of sinoacutine and salutaridine were analyzed. The classification and pharmacological action of isoquinoline alkaloids were discussed. It was suggested that sinoacutine should be separated from morphinane and classified as sinomenine alkaloids.

A new biphenanthrene with cytotoxic activity from Liparis nervosa (Thunb.) Lindl.

2,7,2'-Trihydroxy-3,4,4'7'-tetramethoxy-1,1'-biphenanthrene (1), a previously undescribed biphenanthrene, and five known phenanthrenes, i.e. 2,5-dihydroxy-4-methoxy-9,10-dihydroxyphenanthrene (2), 2,4-dihydroxy -7-methoxy-9,10-dihydroxyphenanthrene (3), 7-hydroxy-2-methoxy-phenanthrene-1,4-dione (4), 7-hydroxy-2-methoxy-9,10-dihydro-phenanthrene-1,4-dione (5), and 4,4',7,7'-tetrahydroxy-2,2'-dimethoxy-9,9',10,10'-tetrahydro-1,1'-biphenanthrene (6) were isolated from the whole plant (stems, leaves, roots and fruits) of Liparis nervosa (Thunb.) Lindl., which is a medicinal plant of the genus Liparis in the Orchidaceae family. The structures of isolates were identified using spectroscopic methods, including NMR and mass spectrometry. Additionally, the cytotoxic potency of all the isolates against human lung cancer A549 cell line was evaluated by an MTT assay. All the isolated compounds showed cytotoxic activities with IC50 values in the range of 10.20 ± 0.81 to 42.41 ± 2.34 µM. The obtained data highlight the importance of L. nervosa as a source of natural lead compounds for cancer therapy.

Bioactivity-Guided Isolation of Cytotoxic Phenanthrenes from Spiranthes sinensis.

Bioactivity-guided separation led to the isolation of six novel phenanthrenes, spiranthesphenanthrenes A-F (1-6), together with 19 known compounds, including seven phenanthrenes (7-13), one bibenzyl compound (14), five flavonoids (15-16 and 20-22), and six simple phenolic compounds (17-19 and 23-25), from the petroleum ether (PE) and ethyl acetate (EtOAc) extracts of Spiranthes sinensis (Pers.) Ames, an edible medicinal plant named "panlongshen" in Chinese that is popularly used in medicinal foods and herbal teas. The structures of the obtained compounds were identified on the basis of extensive NMR spectroscopy and HR-ESI-MS analyses. The cytotoxicities of the phenanthrenes (1-13), the bibenzyl compound (14) , and the flavonoids (15-16 and 20-22) toward SGC-7901, HepG2, and B16-F10 cell lines were examined in vitro. Compounds 1 and 7 exhibited moderate cytotoxic activities toward all of the selected cancer cell lines, and their IC50 values ranged from 19.0 ± 7.3 to 30.2 ± 5.6 µM. Spiranthesphenanthrene A (1) exhibited higher cytotoxic activity than the positive control cisplatin toward the B16-F10 cell line (IC50 = 19.0 ± 7.3 µM). A wound healing assay revealed the inhibition of the migration of B16-F10 cancer cells in a time- and dose-dependent pattern by treatment with 2.5, 5, and 10 µM solutions of compound 1 for 24 and 48 h, respectively. Western blots revealed that compound 1 obviously increased the level of the E-cadherin protein (an epithelial marker) and decreased the levels of the vimentin and N-cadherin proteins (mesenchymal markers). Furthermore, the level of the transcription factor Snail was also obviously decreased by compound 1 in a dose-dependent manner. Taken together, compound 1 inhibits the migration of B16-F10 cancer cells, which may be closely related to the inhibition of the epithelial-mesenchymal transition. Compound 1 represents a promising drug candidate for the prevention of tumor metastasis.

Transcriptome analysis of three cultivars of Poria cocos reveals genes related to the biosynthesis of polysaccharides.

Poria cocos (P. cocos) polysaccharides (PCPs) are used to improve immunity and possess antitumor activities. We compared three cultivars of P. cocos (5.78, XJ 28 and JHYH) PCP contents. Then we determined that malZ, galA, SORD, gnl and bglX are key enzymes within the PCP biosynthetic pathway by using HiSeq2500 transcriptome and qRT-PCR validation. Our results provide more detailed information about the PCP biosynthesis pathway at the molecular level in P. cocos and establish the functions for the molecular breeding to produce polysaccharides in general for therapeutic use in Chinese medicinal plants.

Bioactivity-guided isolation of biphenanthrenes from Liparis nervosa.

Three new biphenanthrenes, Liparisphenanthrenes A-C (1-3), along with three known ones were obtained from the ethanolic extract of Liparis nervosa (Orchidaceae) by bioactivity-guided fractionation. Their structures were elucidated on the basis of extensive spectroscopic analysis. All the compounds obtained were tested in vitro for cytotoxic activities against stomach (HGC-27) and colon (HT-29) cancer cell lines. 1, 4 and 5 showed potent cytotoxicities to HGC-27 cell line with IC50 values of 8.21-9.95µmol/L, and 1 and 5 also exhibited potent cytotoxic activities to HT-29 cell line with IC50 values of 8.53-9.27µmol/L.