Gigantol is a phenolic substance extracted from plants in the genus Dendrobium and used in traditional Chinese medicine. In the present study, we aimed to investigate the growth inhibition and apoptotic effects of gigantol on human liver cancer cells through the PI3K/Akt/NF-κB signaling pathway. HepG2 cells were treated with different concentrations of gigantol (0-150 µM) for 12, 24 and 48 h. It was found that gigantol significantly inhibited the proliferation and induced apoptosis of the HepG2 cells. The results of fluorescence micrographs showed that a 48-h treatment with gigantol induced typical apoptotic morphological features, which were consistent with the flow cytometric analysis where 20% of apoptotic cells were detected in response to gigantol treatment. In addition, western blot analysis indicated that gigantol enhanced the activities of caspase-3, PARP and p53 and downregulated the expression of p-Akt/Akt. Collectively, the present data suggest that gigantol induces growth inhibition and apoptosis of HepG2 cells via the PI3K/Akt/NF-κB signaling pathway.

BackgroundXingnaojing (XNJ), a well known prescription in traditional Chinese medicine, has been used for treatment of stroke in China. However, the effects and mechanisms of XNJ on autophagy are not clear. Here, we used the cell models of autophagy induced by serum-free condition and ischemia stroke in rats to further investigate whether the p53-DRAM pathway is involved in the effects of XNJ on autophagy.MethodsWe used the cell model of autophagy induced by serum-free condition and the rat model of ischemia caused by a middle cerebral artery occlusion (MCAO). The effects of XNJ on p53 transcriptional activity of PC12 cells were evaluated by the luciferase activity assay. The mRNA levels and the expression of p53 and its target autophagy gene DRAM (damage-regulated autophagy modulator) were analyzed respectively by Quantitative-RTPCR and Western blot assay. The activation of autophagy was detected by the levels of autophagy markers, microtubule associated protein light chain 3 (LC3) and p62 by Immunofluorescence and Western blot. p53 inhibitor was used to determine whether p53 is responsible for the effects of XNJ on preventing autophagy.ResultsThe assay for luciferase activity of p53 promoter indicated that XNJ inhibited p53 transcriptional activity. XNJ reduced the expression of p53 and its target autophagy gene DRAM (damage-regulated autophagy modulator) in serum-free condition PC12 cells and the cortex in MCAO rats. XNJ reduced autophagy of PC12 cells induced by serum-free condition and the cortex in MCAO rats. Furthermore, suppression of p53 by p53 inhibitor significantly reduced the effects of XNJ on the autophagy of PC12 cells in serum-free condition.ConclusionXNJ prevents autophagy in experimental stroke by repressing p53/DRAM pathway. Our findings are therefore of considerable therapeutic significance and provide the novel and potential application of XNJ for the treatment of brain diseases.

Anthocyanins, a group of flavonoids, are widely present in plants and determine the colors of the peels of stems, fruits, and flowers. In this study, we used UHPLC-ESI-MS to identify anthocyanins in the herbal plant Dendrobium officinale, which has been used for centuries in China. The results indicated that the total anthocyanin content in samples from Guangxi was the highest. Seven anthocyanins were identified, and the fragmentation pathways were proposed from D. officinale. Most of the identified anthocyanins were composed of cyanidin and sinapoyl groups. We also carried out that the sinapoyl group had active sites on breast cancer receptors by using Schrödinger. The relative levels of the 7 anthocyanins in the samples from the three locations were determined. Transcriptomic analysis was used to analyze the sinapoyl anthocyanin synthesis-related genes in plants, such as genes encoding UGTs and serine carboxypeptidase. We speculated that sinapoyl anthocyanin biosynthesis was associated with the activities of certain enzymes, including chalcone flavonone isomerase-like, hydroxycinnamoyltransferase 1, UGT-83A1, UGT-88B1 isoform X1, serine carboxypeptidase-like 18 isoform X3, and serine carboxypeptidase-like 18.

Different molecular weight polysaccharides of Dendrobium officinale (DOPs) have gradually attracted attention because of their broad biological activities. They, however, remain poorly defined whether their antitumor activity is associated with molecular weight. In this study, the physicochemical, antioxidant, and antitumor properties of DOPs, including the crude polysaccharide (DOP) and its six degradation fractions (DOP1–DOP6) extracted from Dendrobium officinale, were determined. Consequently, DOPs were mainly composed of different ratios of mannose and glucose as follows: 5.15 : 1, 4.62 : 1, 4.19 : 1, 4.46 : 1, 4.32 : 1, 4.29 : 1, and 4.23 : 1, and their molecular weights were significantly different ranging from 652.29 kDa to 11.10 kDa. With the concentration increase of DOPs, the scavenging capacity against OH and DPPH free radicals increased. The antitumor ability of DOPs was different that DOP1–DOP5 (Mw: 176.29 kDa–28.48 kDa) exhibited the best antiproliferation activity than DOP (Mw: 652.29 kDa) and DOP6 (Mw: 11.10 kDa) in HeLa cells rather than PC9, A549, and HepG2 cells. Moreover, it is worth mentioning that DOP1 and DOP5 showed stronger capability on inducing apoptosis of HeLa cells than DOP and DOP6 via the mitochondrial pathway by upregulating the ratio of the Bax/Bal-2 mRNA expression. The results demonstrated that DOPs can be used as the potential natural antioxidant and antitumor products in pharmaceutical industries, and the molecular weight is a crucial influential factor of their antitumor activity that 28.48 kDa–176.29 kDa is a suitable range we may refer to.

Bone marrow mesenchymal stem cell (BMSC) transplants are promising for the treatment of certain central nervous system diseases. However, oxidative stress is one of the major factors that may limit the survival of the transplanted BMSCs. The present study investigated the effect of pretreatment with gigantol on hydrogen peroxide (H2O2)‑induced apoptosis in rat BMSCs (rBMSCs) and the potential underlying mechanisms. The results demonstrated that gigantol pretreatment significantly inhibited H2O2‑induced apoptosis of rBMSCs. rBMSCs were incubated with 600 µM H2O2 in the absence or presence of different doses of gigantol (1‑100 µM). Cell viability and apoptosis ratios were assessed by MTT assays and flow cytometry, respectively. Morphological alterations and reactive oxygen species were measured by the fluorescent‑based methods of Hoechst staining and dichlorodihydrofluorescein diacetate, respectively. Furthermore, the protein levels of phosphorylated‑protein kinase B (Akt), B‑cell lymphoma‑2 (Bcl‑2), Bcl‑2‑associated X (Bax), caspase‑3 and caspase‑9 were investigated by western blotting. Following incubation with H2O2 for 2 h, gigantol significantly inhibited the H2O2‑induced reductions in the cell viability of rBMSCs in a dose‑dependent manner. Furthermore, gigantol upregulated Akt phosphorylation and Bcl‑2 expression, downregulated Bax expression, and reduced the expression of caspase‑3 and caspase‑9 in H2O2‑treated rBMSCs, whereas an opposite effect was detected when LY294002, an inhibitor of phosphatidylinositol 3‑kinase, was administered in combination with gigantol. These results indicate that gigantol may be developed as a promising neuroprotective agent for successful MSC transplantation in ischemic diseases.