Gigantol

Sesquiterpene amino ether and cytotoxic phenols from Dendrobium wardianum Warner.[Pubmed:28844931]

Fitoterapia. 2017 Oct;122:76-79.

A new bibenzyl derivative, dendrocandin V (1) and a new sesquiterpene amino ether, wardianumine A (2), together with eleven known compounds, including phenanthrenes (denbinobin (3), 9,10-dihydro-denbinobin (4), mostatin (5), loddigesiinols A (6)), bibenzyls (moscatilin (7), 5-hydroxy-3,4'-dimethoxybibenzyl (8), 3,4-dihydroxy-5,4'-dimethoxy bibenzyl (9), dendrocandin A (10), Gigantol (11), dendrocandin U (12)) and an alkaloids (dihydroshihunine, 13) were isolated from the EtOH extraction of stems of Dendrobium wardianum Warner. Isolation of the new compound 2 indicated that N,N-dimethylethanolamine as the key adduction in the synthesis of dendroxine and its analogs in Dendrobium species. The hypothetical biosynthetic pathway of 2 was then postulated. Inspired by literature and traditional usage of the herbal medicine, some compounds were sent for cytotoxic activity and the results indicated that compounds 1, 3, 4, 5 showed cytotoxic activities against five human cancer cell lines (HL-60, A-549, SMMC-7721, MCF-7, and SW-480) with IC50 from 2.33-38.48muM. Among those compounds, 3 and 4 showed cell line selectivity with strong activity comparable to DDP.

Extraction and Analysis of Gigantol from Dendrobium officinale with Response Surface Methodology.[Pubmed:29614010]

Molecules. 2018 Apr 3;23(4). pii: molecules23040818.

In order to optimize the extraction of Gigantol from Dendrobium officinale, the influence of methanol concentration, ultrasonic temperature, and liquid ratio on extraction efficiency was analysed by the response surface analysis method. The results show that the extraction rate reached a maximum when the methanol concentration was 92.98%, the solid-liquid ratio was 27.2 mL/g, and the extraction temperature was 41.41 degrees C. The content of Gigantol of Dendrobium officinale in leaves was significantly higher than that in stems, reaching 4.7942 mug/g. The content of Gigantol in Dendrobium huoshanensis Fengdou was significantly higher than that of other species of Fengdou. This experiment has practical significance for improving the utilization rate of Dendrobium officinale, and provides a reference for the study of the pharmacological and biological activity of Gigantol.

Protective effect of gigantol against hydrogen peroxideinduced apoptosis in rat bone marrow mesenchymal stem cells through the PI3K/Akt pathway.[Pubmed:29257286]

Mol Med Rep. 2018 Feb;17(2):3267-3273.

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 H2O2induced apoptosis of rBMSCs. rBMSCs were incubated with 600 microM H2O2 in the absence or presence of different doses of Gigantol (1100 microM). Cell viability and apoptosis ratios were assessed by MTT assays and flow cytometry, respectively. Morphological alterations and reactive oxygen species were measured by the fluorescentbased methods of Hoechst staining and dichlorodihydrofluorescein diacetate, respectively. Furthermore, the protein levels of phosphorylatedprotein kinase B (Akt), Bcell lymphoma2 (Bcl2), Bcl2associated X (Bax), caspase3 and caspase9 were investigated by western blotting. Following incubation with H2O2 for 2 h, Gigantol significantly inhibited the H2O2induced reductions in the cell viability of rBMSCs in a dosedependent manner. Furthermore, Gigantol upregulated Akt phosphorylation and Bcl2 expression, downregulated Bax expression, and reduced the expression of caspase3 and caspase9 in H2O2treated rBMSCs, whereas an opposite effect was detected when LY294002, an inhibitor of phosphatidylinositol 3kinase, 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.

Dendrobium protoplast co-culture promotes phytochemical assemblage in vitro.[Pubmed:27837285]

Protoplasma. 2017 Jul;254(4):1517-1528.

The present study is intended to analyze the occurrence of potent, low produce, naturally occurring stilbenes in protoplasts of wild species and hybrids of Dendrobium. The wild species selected for the study was Dendrobium ovatum, endemic to Western Ghats of India. Protoplasts were isolated from leaves and tepal tissues of all the species and were cultured purely to generate homofusants and cross-cultured to raise heterofusants. Phytochemical composition of protoplast culture with atypical and pure microcolonies was performed using mass spectrometry. Enzyme cocktail of 4% pectinase together with 2% cellulase displayed the highest competence for protoplast isolations. Maximum protoplast density of 30.11 x 10(4)/ml was obtained from D. ovatum leaves in 2 h. Subcellular features such as the presence of partially formed cell wall, the position of the nucleus, chloroplast density, colony existence, and integrity of the plasma membrane were analyzed. Among the pure and cross-cultured protoplasts, the number of heterofusants and homofusants formed were enumerated. The spectral feature extraction of the mass spectrometry indicated the presence of five phenolic marker compounds, viz., tristin, confusarin, Gigantol, moscatilin, and resveratrol, some of them in pure and others in assorted protoplast cultures raised from Dendrobium leaves and tepals. The study demonstrated that protoplast fusion technique enabled phytochemical assemblage in vitro as stilbenes tend to get restricted either in a tissue or species specific manner. This is the first report showing the presence of resveratrol, moscatilin, tristin, Gigantol, and confusarin in wild and hybrid species from cultured Dendrobium protoplasts in vitro.

Four new glycosides from the stems of Dendrobium fimbriatum Hook.[Pubmed:27798974]

Nat Prod Res. 2017 Apr;31(7):797-801.

Four new glucosides, named as Gigantol-5-O-beta-d-glucopyranoside (1), 9,10-dihydro-aphyllone A-5-O-beta-d-glucopyranoside (2), ficusal-4-O-beta-d-glucopyranoside (3), botrydiol-15-O-beta-d-glucopyranoside (4), together with eight known compounds (5-12) were isolated from the n-BuOH extract of the stems of Dendrobium fimbriatum Hook. Their structures were elucidated by the analyses of spectroscopic data.

Gigantol attenuates the proliferation of human liver cancer HepG2 cells through the PI3K/Akt/NF-kappaB signaling pathway.[Pubmed:27959444]

Oncol Rep. 2017 Feb;37(2):865-870.

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-kappaB signaling pathway. HepG2 cells were treated with different concentrations of Gigantol (0-150 microM) 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-kappaB signaling pathway.