Adventitious root culture of Lessertia frutescens for the production of triterpenoid saponins and polysaccharides.

Lessertia frutescens is a perennial shrub of commercial importance in South Africa, but the scarcity of plant resources has limited current product production. In this study, to provide an alternative approach for obtaining L. frutescens material, adventitious roots (ARs) were induced from sterilized seedlings and cultured in a suspension culture system. During this process, selection tests were conducted to find a suitable auxin and its concentration for AR induction and a suitable basal medium for AR growth and metabolite accumulation; a kinetic study was then performed to constructure kinetic models. The results showed that compared to other auxins and concentrations, indole-3-butyric acid at 3 mg/L was suitable for increasing the number and length of ARs during AR induction. In AR suspension culture, Schenk and Hildebrandt (SH) was better than other basal media, and the maximum AR fresh (86.9 g/L) or dry weight (5.5 g/L), total triterpenoid saponin (92.6 mg/g DW), and polysaccharide (114.7 mg/g DW) contents were determined in the 1.5×SH medium. In addition, AR biomass and metabolite contents reached the maximum on day 42. The kinetic models for AR growth and triterpenoid and polysaccharide production were constructed, providing the basis for further optimization of culture conditions and large-scale culture.

Optimizing elicitation strategy of salicylic acid for flavonoid and phenolic production of fed-batch cultured Oplopanax elatus adventitious roots.

Oplopanax elatus is a valuable medicinal plant, but its plant resource is lacking. Adventitious root (AR) culture of O. elatus is an effective way for the production of plant materials. Salicylic acid (SA) exerts enhancement effect on metabolite synthesis in some plant cell/organ culture systems. To clarify the elicitation effect of SA on fed-batch cultured O. elatus ARs, this study investigated the effects of SA concentration, and elicitation time and duration. Results showed that flavonoid and phenolic contents, and antioxidant enzyme activity obviously increased when the fed-batch cultured ARs were treated with 100 µM SA for 4 days starting on day 35. Under this elicitation condition, total flavonoid and phenolic contents reached 387 rutin mg/g DW and 128 gallic acid mg/g DW, respectively, which were significantly (p < 0.05) higher than those in the SA-untreated control. In addition, DPPH scavenging and ABTS+ scavenging rates, and Fe2+ chelating rate also greatly increased after SA treatment, and their EC50 values were 0.0117, 0.61, and 3.34 mg/L, respectively, indicating the high antioxidant activity. The findings of the present study revealed that SA could be used as an elicitor to improve the flavonoid and phenolic production in fed-batch O. elatus AR culture.

Purification of Polysaccharides from Orostachys cartilaginous Cell Cultures by Macroporous Resin Absorption and Bioactivities of the Purified Polysaccharides.

Orostachys cartilaginous is a traditional herbal medicine and its cell cultures contain large amounts of polysaccharides. To utilize the cultured O. cartilaginous cells, this study purified the crude polysaccharides of O. cartilaginous cells by macroporous resin absorption and optimized the purification process in the experiment of orthogonal design with four factors (sample concentration and volume, and eluent concentration and volume) and three levels; the antibacterial and anti-cancer effects of the purified polysaccharides (OTP) were further examined. The results showed that polysaccharide purity reached 95 % in the optimized group, i. e., 1.6 mg/mL of sample (crude polysaccharides) concentration, 3.0 bed volume (BV) of sample volume, 65 % eluent (ethanol) concentration, and 3.0 BV of eluent volume. In the antibacterial experiment, the growth of three bacterial species, i. e., Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis was inhibited by OTP, whereas that of Escherichia coli was not affected; the largest diameter of the inhibitory zone was found on B. subtilis; the extracellular alkaline phosphatase activity and the electrical conductivity, nucleic acid, and protein levels of B. subtilis increased after OTP treatment, indicating that the inhibition of B. subtilis growth was caused by the leakage of cell contents. In the anti-cancer experiment, OTP decreased the cell viabilities of the tested human cancer cells, i. e., AGS (gastric cancer), HCT116 (colon cancer), HepG2 (liver cancer), and HeLa (cervical cancer), and the highest inhibitory effect was on HCT116. OTP promoted HCT116 apoptosis and affected the expression of apoptosis-related proteins, i. e., the expression of B-cell lymphoma-2 decreased and that of bcl-2 associated X protein, cytochrome c, caspase 9 and caspase 3 increased. The findings of the present study suggest that O. cartilaginous cell cultures have a potential application in food or drug production.

Selection of initial culture medium in fed-batch bioreactor culture of Rhodiola sachalinensis cells.

In fed-batch culture, numerous factors, such as initial culture conditions and feeding strategies, affect the culture efficiency. Among the factors, the effect of initial culture medium is rarely investigated. In this work, Rhodiola sachalinensis cells were cultured in the fed-batch bioreactor system and the effects of volume, medium strength, and sucrose concentration of initial culture medium on biomass and accumulation of salidroside, polysaccharides, flavonoids, and phenolics were investigated. The results showed that an initial medium volume of 3 L significantly (p < 0.05) increased biomass and the four bioactive compound contents. The maximum biomass and the highest contents of different bioactive compounds were determined at various MS medium strengths. Therefore, analytic hierarchy process (AHP) - technique for order preference by similarity to ideal solution (TOPSIS) was implemented and half-strength MS medium was selected. Furthermore, the effect of sucrose concentration was examined and 30 g/L sucrose in the initial medium was optimal, at which concentration, 39.45 mg/g DW of salidroside, 531.25 mg/g DW of total polysaccharides, 3.89 mg/g DW of total flavonoids, and 10.84 mg/g DW of total phenolics were produced. The findings of the present study provided a reference for further establishing the fed-batch culture system of R. sachalinensis cells.

Co-cultured adventitious roots of Echinacea pallida and Echinacea purpurea inhibit lipopolysaccharide-induced inflammation via MAPK pathway in mouse peritoneal macrophages.

Objective: In order to elucidate the biological activity of the co-cultured adventitious roots (ARs) of Echinacea pallida and Echinacea purpurea and provide theoretical basis for its application, and the anti-inflammatory activities and potential mechanisms of co-cultured ARs were studied. Methods: The experimental materials were obtained by bioreactor co-culture technology and used in the activity research. In this study, mouse macrophages induced by lipopolysaccharide (LPS) were used as in vitro model. Different concentrations of AR extract (50-400 g/mL) were used to treat cells. The expression of pro-inflammatory cytokines was determined using enzyme linked immunosorbent assay. The inducible nitric oxide synthase and cyclooxygenase-2 expression, mitogen-activated protein kinase (MAPK) phosphorylation, and the inhibitor of nuclear factor-kappa B-α levels were determined by the Western blot analysis. Results: In the co-cultured ARs, total flavonoids and total caffeic acid were determined, and the contents of both bioactive compounds were significantly higher than those ARs from the single-species culture. Compared with the control group, the large amount of pro-inflammatory mediators was released after LPS stimulation. However, in the extract groups with different concentrations (25, 50, and 100 g/mL), the production of these pro-inflammatory mediators was inhibited in a dose-dependent manner. Furthermore, the levels of phosphorylation of MAPK proteins, including p-p38, p-c-Jun N-terminal kinase, and p-extracellular regulated protein kinases were significantly (P < 0.05) decreased in the extract groups, revealing that the AR extract probably involved in regulating the MAPK signaling pathway. Conclusion: Collectively, our findings suggested that the co-cultured ARs of E. pallida and E. purpurea can inhibit production of pro-inflammatory mediators in mouse peritoneal macrophages and possess the anti-inflammatory effect by regulating MAPK signaling pathways.

[Effect of methyl jasmonate on salidroside and polysaccharide accumulation in Rhodiola sachalinensis callus].

OBJECTIVE: To provide a new material for producing the Rhodiolasachalinensis products, the effect of methyl jasmonate (MeJA) on callus biomass and effective compound accumulation of Rhodiolasachalinensis was studied. METHOD: The calluses-cultured in 3 L-air lift balloon type bioreactor were treated with MeJA after 20 d of bioreactor culture and the effect of MeJA concentration and treatment days on callus biomass, salidroside or polysaccharide accumulation and superoxide dismutase (SOD) and peroxidase (POD) activities were investigated. RESULT: The callus biomass was not significantly different after MeJA treatment (125) for 0-6 d but obviously decreased after 6 d treatment. The maximum salidroside or polysaccharide contents and SOD or POD activities were found after 4 d treatment of MeJA. MeJA concentration significantly affected callus biomass and effective compound accumulation, biomass decreased at MeJA concentrations higher than 125 µmol x L(-1). However, the effective compound contents were determined at higher MeJA concentration, and the highest salidroside and polysaccharide accumulation was found at 225 and 275 µmol x L(-1) MeJA, respectively and the maximum SOD and POD activities was found at 225 µmol x L(-1) MeJA. The effective compound contents in callus were compared with field-grown plants. Salidroside contents in calluses were 1.1-fold and 2. 4-fold more than in plant roots and stem or leave, respectively. Polysaccharide content in calluses were 3. 6-fold and 8.0-fold more than in plant roots and stem or leave, respectively. CONCLUSION: Salidorside and polysaccharide in Rhodiolasachalinensiscalluses improved by MeJA treatment, 225 µmol x L(-1) MeJA and 4 d treatment were optimal. The effective compound contents in callus were obviously higher than in field-grown plants. Therefore, bioreactor culture is efficient for obtaining mass effective compounds of Rhodiolasachalinensis by culturing calluses. This method could provide an alternative material source for production of Rhodiolasachalinensis products.

[Effects of several factors on cell growth and ginsenoside accumulation of Panax ginseng suspension culture].

To improve cell suspension culture system of Panax ginseng, the dynamic of cell growth and medium consumption were studied, and the effects of filter on the culture vessel, revolution number, and inoculation density on cell growth and ginsenoside accumulation were also investigated. The maximum cell growth and ginsenoside accumulation was found on the 20th days of suspension culture, therefore, 20 days were confirmed as a suitable culture period for mass production of ginsenoside. Cell growth and ginsenoside content were promoted when the culture vessel had a ventilated filter. Revolution speed during suspension culture affected cell growth, but not ginsenoside content, a peak of ginsenoside productivity was found in the treatment of 120 r x min(-1). Inoculation density also influenced cell growth and ginsenoside accumulation, inoculation density of 6 g was better than other inoculation densities, the ginsenoside content and productivity were up to 12.8 mg x g(-1) DW and 146.6 mg x L(-1), respectively.

[Effects of acid and alkali stress on ginsenoside content and histochemical localization of ginsenoside in adventitious root of Panax ginseng].

To investigate the effect of acid and alkali stress on ginsenoside content of Panax ginseng, adventitious roots culture in bioreactors were incubated for 30 d and pH value was adjusted. Ginsenoside content increased by reducing or raising the pH in culture medium, the muxium ginsenoside content was determined on the 5th days after acid treatment and on the 7th days after alkali treatment. The result of histochemical localization of ginsenoside revealed that the red color from light to dark were found in the adventitious root tissue, and ginsenoside mainly located in the pericycle cells where appeared the dark red color.

[Cultivation of protocorms of Dendrobium candidum in air-lift bioreactors].

OBJECTIVE: To explore the factors affecting the growth of protocorms of Dendrobium candidum and substance synthesis in a reactor, in order to provide a new method for mass production of raw materials of D. candidum. METHOD: Protocorms in vitro were used as experimental materials to study the effect of inoculum volume, light intensity and air volume on the growth of protocorms of D. candidum and the accumulation of polysaccharide and dendrobine in a 3 L-air lift balloon type bioreactor. RESULT: After 30 days of cultivation in a bioreactor, protocorms became dark green and grew well at the inoculum volume of 10 g x L(-1). The polysaccharide content in protocorms showed no difference at various inoculum volumes; whereas the dendrobine content showed differences (with the highest treatment at the inoculum volume of 10 g x L(-1)), particularly the productions of polysaccharide and alkaloid reached the maximum at the inoculum volume of 10 g x L(-1). The condition of 1 600 lx of light intensity was the most favorable for the growth of protocorms. Though light played a role of improving the accumulation of polysaccharide in protocorms of D. candidum, it could inhibit the accumulation of dendrobine. Polysaccharide content and production were better under light conditions of 1 600 and 2 400 lx than dark conditions. Despite the maximum dendrobine content in dark conditions, the dendrobine production showed the maximum in the light condition of 1 600 lx due to poor growth of protocorms. Protocorms grew well and became dark green at the air volume of 0.2 vvm (air volume culture volume per minute) , which was better than at 0.1 and 0.3, with maximum polysaccharide and dendrobine contents and productions. CONCLUSION: In a 3 L-air lift balloon type bioreactor with a working volume of 2 L, the conditions of 10 inoculum volume, 1 600 lx light intensity and 0.2 air volume were favorable for the growth of protocorms and the production of dendrobine. This demonstrates that the cultivation of D. candidum and substance synthesis in a reactor is an effectie approach for mass production of polysaccharide and dendrobine.

[Preliminary study on cultivation of adventitious roots of Hypericum perforatum in bioreactors].

OBJECTIVE: To cultivate adventitious roots of Hypericum perforatum in bioreactors, in order to seek for suitable conditions for adventitious growth. METHOD: The effect of IBA concentration, sugar type and concentration, inoculum volume and air volume of adventitious roots on the cultivation of adventitious roots of H. perforatum was observed in a 5 L air-lift bioreactor. RESULT: Adventitious roots of H. perforatum were cultivated in a MS culture dish. With the increase of IBA concentration, the propagation coefficient of adventitious roots of H. perforatum was on the rise. The IBA concentration ranging between 1.25-1.75 mg x L(-1) was suitable for the growth of adventitious roots. Adventitious roots grew best with sucrose in MS medium, with the propagation coefficient up to 22.15. When sucrose concentration was 30 g x L(-1), fresh weight, dry weight and propagation coefficient reached the maximum value. An adventitious root reactor with an inoculum volume of 20 g was favorable for the growth of adventitious roots. The air volume of reactors of 0.075 vvm (air volume/culture volume per minute) was favorable for the growth of adventitious roots, with the significant increase in the propagation coefficient of adventitious roots. In the amplification experiment, we found that the cultivation conditions of adventitious roots in a 5 L bioreactor was completely applicable to that in 10 and 20 L bioreactors, and adventitious roots grew well in a large bioreactor. CONCLUSION: IBA concentration, sugar type and concentration, inoculum volume and air volume had a significant effect on the growth of adventitious roots.