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Additional file 1: Table S1. Donor characteristics of human liver samples. Table S2. Primers for quantitative real-time polymerase chain reaction.

The stems of Dryopteris crassirhizoma, one of the main components of Lianhua-Qingwen Formula (LQF) was traditionally used for heat-clearing and detoxifying. Dryocrassin ABBA is a key antiviral component in the herbal medicine while the compound is hard to get in large amounts with the features of homologous compounds, polyphenol groups, and low contents. Therefore, the present work aims to seek influenza H7N9 virus inhibitors from natural source by synthesis of dryocrassin ABBA and its analogues. As a result, total synthesis of the compound was achieved in nine steps with an over-all yield of 4.6%. Neuraminidases (NAs) inhibitory activities of the synthesized product and its analogues were evaluated afterward. Comparing with the positive control, OSV (9.6 μM), it was very exciting that dryocrassin ABBA and its analogues (b5 and e2) showed better NAs inhibitory activity against Anhui H7N9 with IC50 values of 3.6 μM, 2.5 μM and 1.6 μM. For the highly resistant Shanghai N9, these compounds can also show medium inhibitory activities. Docking results indicated the direct interaction of synthesized 3 hits with the key K294 by hydrogen bonds, but no direct interaction of OSV with the key K294 was observed in Shanghai N9. This study suggested that dryocrassin ABBA and its analogues especially AB, which consisted of polyphenol groups may have beneficial effects on treating avian influenza H7N9 virus.

Ten previously undescribed stilbenoids, including six bibenzyls (bleochrins A–F, 1–6), three phenanthrenes derivatives (bleochrins G–J, 7–10) along with eleven known compounds were isolated from the rhizomes of Bletilla ochracea Schltr. The structural characterizations of 1–21 were accomplished by spectroscopic data, while the absolute stereostructure of 6 was confirmed by electronic circular dichroism (ECD) data analyses. All isolated metabolites except 7 were evaluated for cytotoxic activity against five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW480). Four isolates exhibited significant inhibitory ability against HL-60, SMMC-7721, and MCF-7 cell lines, with IC50 values ranging from 0.79 to 6.57 μM. The isolates were tested further for inhibitory effects on the NO production of the liposaccharide (LPS)-induced RAW264.7 macrophages and showed activity with IC50 values at 15.29–24.02 μM.

Two polysaccharides, named DOP-1 and DOP-2, with molecular weights of 6.8 kDa and 14.3 kDa, respectively, were isolated and purified from the stems of Dendrobium officinale. Monosaccharide composition, Fourier-transform infrared spectroscopy, methylation, and nuclear magnetic resonance analyses indicated that DOP-1 and DOP-2 may have a backbone consisted of →4)-β- d -Glcp-(1→, →4)-β- d -Manp-(1→, →4)-2-O-acetyl-β- d -Manp-(1→ and →4)-3-O-acetyl-β- d -Manp-(1→. In vivo assays showed that D. officinale polysaccharides (DOPs) exerted significant hypoglycemic effects accompanying increased serum insulin and glucagon-like peptide-1 (GLP-1) levels in streptozotocin-induced diabetic rats. Further in vitro experiments showed that DOP-induced GLP-1 secretion was inhibited by an intracellular calcium chelator, a Ca2+/calmodulin-dependent protein kinase (CaMK) II inhibitor, a specific calcium-sensing receptor antagonist, and a p38-mitogen-activated protein kinases (MAPK) inhibitor. These results indicated that DOPs may decrease fasting blood sugar levels by stimulating GLP-1 secretion and that intracellular DOP-induced GLP-1 secretion involved the Ca2+/calmodulin/CaMKII and MAPK pathways.