Dendrobium officinale is a precious medicinal herb and health food, and its pharmacological actions have been studied and proved. However, the mechanisms by which its active flavonoid glycosides affect epithelial–mesenchymal transition (EMT) in hepatocellular carcinoma (HCC) cells, such as HepG2 and Bel-7402 cells, have not been previously investigated. Therefore, we investigated whether isoviolanthin extracted from the leaves of Dendrobium officinale inhibits transforming growth factor (TGF)-β1-induced EMT in HCC cells. In this study, the physicochemical properties and structure of isoviolanthin were identified by HPLC, UV, ESIMS, and NMR and were compared with literature data. HCC cells were pretreated with 10 ng/mL TGF-β1 to induce EMT and then treated with isoviolanthin. Herein, we found that isoviolanthin exhibited no cytotoxic effects on normal liver LO2 cells but notably reduced the migratory and invasive capacities of TGF-β1-treated HCC cells. Additionally, isoviolanthin treatment decreased matrix metalloproteinase (MMP)-2 and -9 levels, and remarkably altered the expression of EMT markers via regulating the TGF-β/Smad and PI3K/Akt/mTOR signaling pathways; Western blot analysis confirmed that the effects of the inhibitors SB431542 and LY294002 were consistent with those of isoviolanthin. These findings demonstrate the potential of isoviolanthin as a therapeutic agent for the treatment of advanced-stage metastatic HCC.

ViceninII is a naturally flavonoid glycoside extracted from Dendrobium officinale, a precious Chinese traditional herb, has been proven to be valuable for cancer treatment. Transforming growth factor-β1 (TGF-β1), promotes the induction of epithelial–mesenchymal transition (EMT), a process involved in the metastasis of cells that leads to enhanced migration and invasion. However, there is no previously evidence that ViceninII has an inhibitory effect on cancer metastasis, specifically on the TGF-β1-induced EMT process in lung adenocarcinoma cells. In this experiment, we used UV, ESIMS, and NMR to identify the structure of ViceninII.A549 and H1299 cells were treated with TGF-β1 in the absence and presence of ViceninII, and subsequent migration and invasion were measured by wound-healing and transwell assays. The protein localization and expressions were detected by immunofluorescence and Western blotting. The results indicated that TGF-β1 induced spindle-shaped changes, increased migration and invasion, and upregulated or downregulated the relative expression of EMT biomarkers. Meanwhile, these alterations were significantly inhibited when co-treated with ViceninII and inhibitors LY294002 and SB431542. In conclusion, ViceninII inhibited TGF-β1-induced EMT via the deactivation of TGF-β/Smad and PI3K/Akt/mTOR signaling pathways.This is the first time that the anti-metastatic effects of ViceninII have been demonstrated, and their molecular mechanisms provided.

Dendrobium huoshanense, a unique species in the genus Orchidaceae, is only found in China and is known as “mihu”. Due to the lack of quality control, the use of D. huoshanense in the herbal market has been limited. In this study, methods based on thin‐layer chromatography, high‐performance liquid chromatography and high‐performance liquid chromatography coupled with electrospray ionization multi‐stage tandem mass spectrometry were used to identify the flavonoids in D. huoshanense and distinguish this species from other Dendrobium species. Using thin‐layer chromatography, a characteristic band was observed for D. huoshanense, and this band was absent from the thin‐layer chromatography plates of other Dendrobium species. Then, using high‐performance liquid chromatography, nine peaks of flavonoids were observed in the chromatograms of ten batches of D. huoshanense. Ultimately, 22 flavonoids in D. huoshanense were identified by multi‐stage tandem mass spectrometry, and 11 of these compounds are being reported from D. huoshanense for the first time. In addition, two compounds both with molecular weights of 710, were identified as being unique to D. huoshanense; one of these compounds, apigenin‐6‐C‐α‐L‐rhamnosyl‐(1→2)‐β‐D‐glucoside‐8‐C‐α‐L‐arabinoside, was proven to be responsible for the characteristic thin‐layer chromatography band of D. huoshanense. These analysis methods can be applied for the identification and quality control of D. Huoshanense.

BackgroundDendrobium officinale as a precious traditional Chinese herb is widely used in medicines and health supplements. Thus the extraction, purification and biological activities of polysaccharides from the stem of Dendrobium officinale have significant meaning on theory and application value.MethodsThe crude Dendrobium officinale polysaccharide (DOP) was obtained by hot water extraction- ethanol precipitation method, and four new polysaccharide fractions (DOP-40, DOP-50, DOP-60, and DOP-70) were further obtained from the crude DOP by fractional precipitation with ethanol method, then four fractions were further purified by Toyopearl-H65F gel resin. The molecular weight and monosaccharide composition of four purified fractions were determined by high performance anion exchange chromatography and high performance liquid chromatography. The antioxidant activities of them were evaluated by the reducing power assay, and the superoxide anion, 2,2-diphenyl-1-picrylhydrazyl (DPPH), and hydroxyl free radicals scavenging assays, respectively. Finally, the anticancer activities of them were investigated via the MTT assay and the western blot analysis using HepG2 cells.ResultsAmong these four purified fractions were mainly composed of d-mannose and d-glucose with different molar ratios, and their average molecular weights were 999, 657, 243 and 50.3 kDa, respectively. What’s more, DOP-70 always exhibited the strongest antioxidant and anticancer activities, while DOP-40 and DOP-60 showed very close antioxidant and anticancer activities which were better than that of DOP-50. The western blotting analysis also showed that DOP-40, DOP-60, and DOP-70 induced apoptosis in HepG2 human liver cancer cells through the Bcl-2 and Bax-dependent pathway.ConclusionsFractional precipitation with ethanol could successfully apply to extract four new polysaccharide fractions from Dendrobium officinale stems, and the polysaccharide fractions possessed efficient antioxidant and anticancer activities, especially DOP-70.

Dendrobium officinale is a widely used medicinal plant in China with numerous bio-activities. However, the main structure and anti-tumor activity of the polysaccharides from this plant have not been investigated. In this study, we elucidated the main structure of polysaccharides purified with DEAE and Sephadex G-25 from Dendrobium officinale grown under different planting conditions. In addition, the anti-tumor activity was tested via MTT assays. The results showed that the polysaccharides of Dendrobium officinale grown under different conditions were almost the same, with slight differences in the branched chain; both polysaccharide fractions consisted of (1→4)-linked mannose and (1→4)-linked glucose, with an O-acetyl group in the mannose. After degradation, the polysaccharide fractions from wild plants showed significant anti-proliferation activity in HeLa cells. The fractions F1 and F3 induced apoptosis by up-regulating the expression of ERK, JNK, and p38. We concluded that polysaccharides from Dendrobium officinale planted in the wild exhibit significant anti-tumor effects only after being degraded to smaller molecular weight species. The planting mode is a significant factor in the pharmacological activity of Dendrobium officinale. We advise that the planting conditions for Dendrobium officinale should be changed.