Developing a Procedure of Extracting Total Polysaccharide from Dendrobium Nobile Lindl. in Vietnam

Dendrobium nobile Lind., also known as Hoang thao dui ga, is a species of plant belonging to the genus Dendrobium, a large genus of the Orchidaceae. This is a medical plant used in many remedies in China and Vietnam. Polysaccharide from this species has been shown many valuable biological activities such as hypoglycemia antioxidant and anti-cancer. In this paper, a procedure for extracting total polysaccharide by aqueous solvent from D.nobile based on the survey of factors: temperature, time, material/solvent ratio affecting this extraction process was proposed. The total polysaccharide content was also determined according to phenol-sulfuric acid method.

Protective Effects and Mechanisms of Dendrobium nobile Lindl. Alkaloids on PC12 Cell Damage Induced by Aβ25-35

Background. Aβ deposition abnormally in the mitochondria can damage the mitochondrial respiratory chain and activate the mitochondrial-mediated apoptosis pathway, resulting in AD-like symptoms. Objective. To observe the protective effects of Dendrobium nobile Lindl. alkaloids (DNLA) on Aβ25-35-induced oxidative stress and apoptosis in PC12 cells explore its possible protective mechanisms. Methods. PC12 cells were treated with DNLA with different concentrations (0.035 mg/L, 0.3 mg/L, and 3.5 mg/L) for 6 h, followed by administration with Aβ25-35 (10 μM) for 24 h. MTT assay and flow cytometer observe the effect of DNLA on Aβ25-35-induced cytotoxicity and apoptosis of PC12 cell. Based on the mitochondrial apoptosis pathway to study the antiapoptotic effect of DNLA on this model and its relationship with oxidative stress, flow cytometer detected the level of reactive oxygen species (ROS), and ELISA kits were used to detect superoxide dismutase activity (SOD) and glutathione (GSH) content in cells. The JC-1 fluorescent staining observed the effect of DNLA on the mitochondrial membrane potential (MMP) with inverted immunofluorescence microscopy. Western blot was used to detect the levels of mitochondrial apoptosis pathway-related protein and its major downstream proteins Bax, Bcl-2, cleaved-caspase-9, and cleaved-caspase-3. Results. DNLA can significantly improve the viability and apoptosis rate of PC12 cell damage induced by Aβ25-35. It also can restore the reduced intracellular ROS content and MMP, while SOD activity and GSH content increase significantly. The expression of apoptosis-related protein Bax, cleaved-caspase-9, and cleaved-caspase-3 decreased when the Bcl-2 protein expression was significantly increased. Conclusion. These findings suggest that it can significantly inhibit the apoptosis of PC12 cell damage induced by Aβ25-35. The mechanism may reduce the level of cellular oxidative stress and thus inhibit the mitochondrial-mediated apoptosis pathway.

Morphophysiology and Cryopreservation of Seeds of Dendrobium Nobile Lindl. (Orchidaceae) at Different Stages of Development

We studied the seed maturation of Dendrobium nobile Lindl to establish the optimal stage for green pod culture and long-term storage in liquid nitrogen. It was found that the immature seeds can germinate in vitro starting from 3 months after pollination (MAP) but only develop up to the stage of embryo swelling or protocorm without rhizoids. The maximum staining of embryos with vital dyes FDA and TTC occurs at 4 and 5 MAP that corresponds to the release of suspensor beyond the embryo sac. Embryo staining does not correlate with germination capacity and seed viability in cryogenic storage. The immature seeds acquire resistance to freezing and drying in airflow at the age of 6 MAP. The time of technical maturity for green pod culture and cryopreservation may be reduced from 12 MAP to 6–7 MAP.