Adventitious Root Cultures Research Articles

Enhancement of Sesquiterpenoid Production by Methyl Jasmonate in Atractylodes chinensis Adventitious Root Culture and its Transcriptional Regulation.

The adventitious root (AR) culture of Atractylodes chinensis is an efficient platform for sustainable production of its sesquiterpenoid compounds (atractylon and β-eudesmol). However, their limited accumulation levels need an effective elicitation approach, and the present study solved this problem using methyl jasmonate (MeJA) as an elicitor. The effects of its treatment concentration and duration on metabolite production were investigated. The ARs treated with 100 µM MeJA for seven days increased atractylon and β-eudesmol by 3.64- and 1.90-fold, respectively, compared with the control. This study further performed transcriptome analysis to explore the transcriptional regulation mechanism of the MeJA elicitation. A total of 124,464 unigenes were identified in A. chinensis ARs, of which 3,568 genes were upregulated and 3,864 genes were downregulated under the MeJA treatment. The MeJA treatment activated the endogenous JA biosynthesis and signaling pathways and sesquiterpenoid biosynthesis. The MeJA treatment more significantly activated the MEP pathway than the MVA pathway. In addition, 14 genes encoding terpene synthase were identified to be significantly upregulated. A total of 2,700 transcription factors (TFs) were identified in A. chinensis ARs, of which Tify, MYB, and MADS were significantly enriched under the MeJA treatment. We predicted a new antagonistic interaction between MYC2 and CPP TFs, which was significantly regulated by the MeJA treatment. The results of real-time quantitative PCR and enzyme activity assays proved the reliability of the transcriptome data. This study will help improve the in vitro production system of A. chinensis sesquiterpenoids and understand the transcriptional regulation mechanism of MeJA elicitation.

In vitro adventitious root culture system for optimal production of genistein in soybean (Glycine max L. Merrill)

In vitro adventitious root culture system for optimal production of genistein in soybean (Glycine max L. Merrill)

Methyl Jasmonate Elicitation Enhanced Biomass, Phenolic, and Flavonoid Production of Adventitious Root Culture of Gynura procumbens in Balloon Type Bubble Bioreactor

Methyl Jasmonate Elicitation Enhanced Biomass, Phenolic, and Flavonoid Production of Adventitious Root Culture of Gynura procumbens in Balloon Type Bubble Bioreactor

Enhancement of in vitro production of tropane alkaloids and phenolic compounds in Hyoscyamus niger by culture types and elicitor treatments

This study aimed to determine the effects of 24-epibrasinolide (EBL) and methyl jasmonate (MJ) treatments on growth parameters and secondary metabolite synthesis in adventitious root and cell suspension cultures of Hyoscyamus niger. Therefore, different concentrations (0.5, 1 and 2 mg L−1) of EBL alone and combined with 224.3 mg L−1 (1 mM) MJ were applied to root and cell suspension cultures. 2 mg L−1 and 1 mg L−1 EBL were determined as the treatments in which the highest values were obtained in terms of growth criteria in root and cell cultures, respectively. In root cultures, the highest scopolamine accumulation (2.57 mg g−1) was obtained from the combination of 2 mg L−1 EBL and MJ, while the highest value (0.66 mg g−1) for hyoscyamine was observed in the roots treated with 1 mg L−1 EBL and MJ. In cell cultures, 2 mg L−1 EBL for scopolamine and 0.5 mg L−1 EBL for hyoscyamine were found to be the best applications and calculated as 0.51 µg g−1 and 0.28 µg g−1, respectively. EBL and MJ treatments also stimulated total phenolic content (TPC). The highest TPC in root cultures was detected as 18.01 mg g−1 with the combination of MJ while in cell cultures, maximum TPC was observed in cells applied with 2 mg L−1 EBL and MJ as 11.56 mg g−1. When EBL and MJ were applied to root and cell suspension cultures, significant changes occurred in the amount of phenolic compounds. Co-application of EBL and MJ significantly increased the amount of gallic acid, catechin, epicatechin, cinnamic acid and chlorogenic acid in root cultures. The application of 2 mg L−1 EBL was determined as the most suitable application for gallic acid, catechin, epicatechin, p-coumaric acid, and caffeic acid in cell cultures. It was also found that the metabolite production performance of adventitious roots was higher than that of cells. In conclusion, it was suggested that the use of MJ and EBL may be a promising strategy to enhance the accumulation of scopolamine, hyoscyamine and phenolics in root and cell cultures of H. niger.

Melatonin-Induced Stress Enhanced Biomass and Production of High-Value Secondary Cell Products in Submerged Adventitious Root Cultures of Stevia rebaudiana (Bert.).

Stress is one of the important factors that directly or indirectly affects the plant architecture, biochemical pathways, and growth and development. Melatonin (MEL) is an important stress hormone; however, the exogenous addition of melatonin to culture media stimulates the defense mechanism and releases higher quantities of secondary metabolites. In this study, submerged adventitious root cultures (SARCs) of diabetically important Stevia rebaudiana were exposed to variable concentrations (0.5-5.0 mg/L) of MEL in combination with 0.5 mg/L naphthalene acetic acid (NAA) to investigate the biomass accumulation during growth kinetics with 07 days intervals for a period of 56 days. The effects of exogenous MEL on the biosynthesis of stevioside (Stev.), total phenolics content (TPC), total flavonoids content (TFC), total phenolics production (TPP), total flavonoids production (TFP), total polyphenolics content (TPPC), fresh and dry weight (FW & DW), and antioxidant potential were also studied. Most of the SARCs displayed lag, exponential, stationary, and decline phases with variable biomass accumulation. The maximum fresh (236.54 g/L) and dry biomass (28.64 g/L) was observed in SARCs exposed to 3.0 mg/L MEL and 0.5 mg/L NAA. The same combination of MEL and NAA also enhanced the accumulation of TPC (18.96 mg/g-DW), TFC (6.33 mg/g-DW), TPP (271.51 mg/L), TFP (90.64 mg/L), and TPPC (25.29 mg/g-DW). Similarly, the highest stevioside biosynthesis (91.45 mg/g-DW) and antioxidant potential (86.15%) were observed in SARCs exposed to 3.0 mg/L MEL and NAA. Moreover, a strong correlation was observed between the biomass and the contents of phenolics, flavonoids, antioxidants, and stevioside. These results suggest that MEL is one of multidimensional stress hormones that modulate the biosynthetic pathways to release higher quantities of metabolites of interest for various industrial applications.

Establishment and elicitation of liquid adventitious root cultures of Inula crithmoides L. for increased caffeoylquinic acids production and hepatoprotective properties

This study established a liquid adventitious root culture for Inula crithmoides L. focusing on producing extracts rich in hepatoprotective caffeoylquinic acids through elicitation. Adventitious roots were induced from in vitro-grown plant leaves cultured on MS medium supplemented with 1 mg/L IBA. Growth and secondary metabolites accumulation (phenolics, flavonoids, hydroxycinnamic acids) were monitored weekly to determine the optimal harvesting time. Then, the adventitious roots were elicited for 4 weeks with varying concentrations of yeast extract–YE (50, 100 and 200 mg/L) and extracted with ethanol. The extracts were evaluated for their hepatoprotective effects against ethanol-induced hepatotoxicity and analyzed through high-performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC–ESI–MS/MS). Roots of greenhouse-cultivated plants were used to compare the results obtained from in vitro -grown adventitious roots. IBA supplementation induced 100% adventitious root formation, with maximum biomass and phenolic accumulation after 4 weeks. Hydroxycinnamic acid levels increased significantly with YE treatment at all the concentrations, particularly in case of chlorogenic acid and di-O-caffeoylquinic acid isomers. The root extracts displayed significant in vitro hepatoprotective effects, particularly at 50 mg/L YE elicitation. Overall, the elicitation of I. crithmoides liquid root cultures with yeast extract offers a promising, efficient, and cost-effective approach for optimizing the production of valuable caffeoylquinic acids having potential pharmaceutical use.

Sample pre-treatment strategy for value-added bioactive phytochemicals in adventitious root culture of Eurycoma harmandiana Pierre and evaluation of their anti-inflammatory activity

Sample pre-treatment strategy for value-added bioactive phytochemicals in adventitious root culture of Eurycoma harmandiana Pierre and evaluation of their anti-inflammatory activity

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.

Impact of elicitors and precursor on quassinoids and canthin-6-ones production in adventitious root culture of Eurycoma harmandiana Pierre and improvement of their anti-inflammatory activity

The processes of elicitation and precursor are used to increase the production of secondary metabolites in plant tissue cultures. The roots of Eurycoma harmandiana Pierre, a herbal plant used in traditional Thai medicine, are highly sought after to treat fever and erectile dysfunction. Hence, alternative sources from in vitro plant tissue of interest are needed. This study investigated the growth kinetics of adventitious root culture of E. harmandiana and the effect of various elicitors, including yeast extract (YE), chitosan (CH), 2-hydroxypropyl-β-cyclodextrin (HPCD), and precursor tryptophan (T), to enhance the contents of quassinoids and canthin-6-ones in root biomass and culture media. Elicitors and precursor were added at the 10th week after subculturing, and the root biomass and culture media were harvested on days 7 and 14 after treatment. Canthin-6-ones accumulation on day 14 was up to 2-fold higher than that in the control when the root culture was treated with 200 µM T, and quassinoid accumulation was 3.6-fold higher when elicited with 2 mg/mL YE. 9-Hydroxy-canthin-6-one was the most abundant in the root biomass after addition of CH (200 ppm), while only eurycomanone and 9-hydroxy-canthin-6-one were found in the culture media. Additionally, on day 14, 9-methoxy-canthin-6-one was found in the media culture of the elicited root with HPCD, whereas it was not found after treatment with the other elicitors. Meanwhile, the morphology of adventitious roots changed after elicitation. The enhancement of quassinoids and canthin-6-ones compounds in the root biomass after elicitation led to stronger anti-inflammatory activity than in the non-treated roots owing to significantly inflammatory gene suppression. This study demonstrates the effective elicitation and precursor feeding of adventitious root cultures of E. harmandiana, which enhanced bioactive components and improved anti-inflammatory effects.

A novel antibacterial and anti-biofilm material: Biosynthetic silver nanoparticles mediated by extract from Oplopanax elatus adventitious roots

The search for plant resources involved in the biosynthesis of silver nanoparticles (AgNPs) is crucial for the diversity of AgNP materials. Oplopanax elatus is a valuable medicinal shrub and its adventitious root (AR) culture is a modern method for producing the raw material. To explore an efficient biosynthetic AgNPs, this study synthesized AgNPs using O. elatus AR extract (OE-AgNPs) and the characterization of OE-AgNPs was performed. Finally, the antibacterial and anti-biofilm effects of OE-AgNPs were investigated. The result showed that OE-AgNPs had an obvious absorption peak of nanosilver with a spherical shape and a silver-like face-centered cubic structure, which the OE-AgNPs were capped by compounds with aliphatic amine, amide, carbonyl, and hydroxyl groups of O. elatus AR extract, indicating a successful synthesis of OE-AgNPs. The 10–40 nm particles were the most abundant in the OE-AgNPs, accounting for 70%. OE-AgNPs had the strongest antibacterial activity against Escherichia coli and Pseudomonas aeruginosa among six bacterial species tested, with a minimum inhibitory concentration (MIC) of 0.75 μg/mL, and the cell contents of E. coli and P. aeruginosa leaked out by OE-AgNP treatment, and bacterial respiration was inhibited. After OE-AgNP treatment, biofilms of E. coli and P. aeruginosa were efficiently scavenged with a scavenging rate of more than 60%; the extracellular polysaccharide concentrations in biofilms were also ruduced. The findings of this study suggested that OE-AgNPs could be used as a potential antibacterial and antibiofilm substance to apply in the product production and indicated the feasibility of expanding the application of O. elatus ARs.

Total Content of Saponins, Phenols and Flavonoids and Antioxidant and Antimicrobial Activity of In Vitro Culture of Allochrusa gypsophiloides (Regel) Schischk Compared to Wild Plants.

Allochrusa gypsophiloides is a rare Central Asian species, a super-producer of triterpene saponins with pharmacological and technical value. In this work, a comparative evaluation of the in vitro culture of adventitious roots (ARs), in vitro adventitious microshoots (ASs), natural roots and aboveground parts of wild plants from Kazakhstan to define the total saponin (TS), phenol (TP) and flavonoid (TF) content, as well as antioxidant (AOA) and antimicrobial activity, is presented for the first time. In the AR culture, growth index (GI), TS, TP and TF were evaluated on days 25, 45 and 60 of cultivation on ½ MS medium without (control) and with auxin application. It was found out that TS and TF were higher in the in vitro AR culture. The amount of TP and TF are higher in the aerial part of vegetative plants with maximum AOA. The concentration of the extract required to inhibit 50% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical formation (ICO50) in extracts from natural material negatively correlated with TS, TP, TF and in the in vitro AR culture with TF. Control extracts from the in vitro AR culture with high TS levels showed growth-inhibitory activity against S. thermophillus, S. cerevisiae and C. albicans. The influence shares of medium composition factor, cultivation duration factor and their interaction with GI, TS, TP and TF were determined. The in vitro AR culture is promising for obtaining triterpene saponins TSR with high antibacterial and antifungal activity, and the in vitro ASs culture-for shoot multiplication with antioxidant properties.

Methyl jasmonate elicitation on increased production of Precocene II from adventitious root cultures of Ageratum conyzoides L. and evaluation of its antioxidant and cytotoxic activities

Methyl jasmonate elicitation on increased production of Precocene II from adventitious root cultures of Ageratum conyzoides L. and evaluation of its antioxidant and cytotoxic activities

The Optimization of Medium Conditions and Auxins in the Induction of Adventitious Roots of Pokeweed (Phytolacca americana L.) and Their Phytochemical Constituents.

Pokeweed, Phytolacca americana L., is considered a widely spreading invasive plant, while saponin contents accumulated in the roots have pharmaceutical uses, such as rheumatism treatments and anti-inflammation. Adventitious root cultures are an important source of diverse secondary metabolites, which have significant applications in various fields. This study focused on the optimization of parameters for root induction using different medium states and treatments with auxins on a pokeweed leaf. Semisolid and liquid MS (Murashige and Skoog, 1962) media were supplemented with indole-3-butyric acid (IBA) and 1-naphthylacetic acid (NAA) at 0.5, 1, 2, and 4 mg/L. Root growth parameters, e.g., induction percentage, root numbers, length, and weight, were measured to determine the adventitious root induction efficiency. Total phenolic content, total flavonoid content, total saponin content, and antioxidant activity were recorded. Results showed that adventitious roots induced in semisolid MS medium supplemented with 0.5 mg/L NAA exhibited a high density of lateral roots. Appropriate medium state and auxin for adventitious root induction in pokeweed were determined as semisolid medium supplemented with 2 mg/L NAA. Considering phytochemicals, adventitious roots induced in liquid medium containing 0.5-1 mg/L NAA had the highest yield extract percentage. Additionally, adventitious roots cultivated in a liquid medium enriched with 1 mg/L NAA exhibited the highest phenolic and saponin contents. A principal component analysis (PCA) biplot and hierarchical cluster analysis (HCA) heatmap demonstrated different response patterns between semisolid and liquid media applied with NAA. The results of the semisolid media were grouped together due to high expression levels of the root induction parameters, while elevated phytochemical values were observed in the liquid media treatments. The results suggested two different media that provide the highest adventitious root induction efficiency and the greatest phytochemical contents: semisolid medium with 2 mg/L NAA and liquid medium with 1 mg/L NAA, respectively. These culture media can be applied to optimize adventitious root culture of pokeweed and in vitro phytochemical production.

Enhanced production of bioactive plumbagin in hairy root cultures and adventitious root cultures of Plumbago zeylanica L. by a novel apocarotenoid elicitor, α-ionone

Plumbagin, a medicinally important secondary metabolite is produced in the roots of Plumbago zeylanica Linn. Natural harvest of plumbagin from roots is a destructive process that destroys the entire plant. The aim of this study was the in vitro production of plumbagin at high concentrations. For this purpose, hairy root cultures (HRCs) and adventitious root cultures (ARCs) were induced from P. zeylanica leaf explants. Additionally, first-time α-ionone was used as an elicitor to trigger plumbagin biosynthesis. HRCs were developed using the two different strains of Agrobacterium rhizogenes (LBA1334, and R1000). R1000 strain showed the highest HR induction efficiency. ARCs were induced from the leaf explants growing in Murashige and Skoog (MS) solid media supplemented with 1 mg/L indole-3-butyric acid. Newly emerged adventitious roots were used to develop root suspension cultures in a liquid MS medium. Plumbagin content was determined by HPLC/DAD. Both HRCs and ARCs showed fast growth kinetics. The greatest increase in the production of plumbagin was achieved with 10 µM α-ionone. As compared to untreated controls, the optimum α-ionone dose resulted in a 3.6-fold and 3.1-fold increase in plumbagin in HRCs, and ARCs, respectively. These results support that α-ionone elicitor-treated HRCs and ARCs are promising technology for improved production of plumbagin to meet commercial demand.

Novel pilot bioreactor for scale up Gynura procumbens adventitious root culture

Adventitious root culture and the development of a bioreactor are methods to obtain biomass and plant bioactive compounds in large quantities faster than conventional plant cultivation. These technologies provide an excellent opportunity to produce biomass and bioactive compounds from plants, especially Gynura procumbens. Previous reports mentioned a small-scale bioreactor could increase biomass and bioactive compounds of G. procumbens adventitious roots. Therefore, a larger bioreactor for adventitious root culture is necessary to develop. In this study, the development of the 19 L pilot bioreactor was successful. The optimal condition for bioreactor sterilization is 1.8 bar for 60 min using an autoclave. We found that G. procumbens adventitious roots culture in pilot bioreactors has resulted in optimal biomass using MS-Tek media (technical grade) compared to MS-PA (pro analyze) media after 35 d of the culture period. Although, higher productivity of total phenolics and total flavonoids in G. procumbens roots has been achieved from MS-PA media rather than MS-Tek media. In further study, it is necessary to evaluate the effect of technical-grade chemicals on kinetics root growth and chemical uptake. The hope is to obtain a suitable media formulation with affordable cost for adventitious root culture production.

Plants, Cells, Algae, and Cyanobacteria In Vitro and Cryobank Collections at the Institute of Plant Physiology, Russian Academy of Sciences-A Platform for Research and Production Center.

Ex situ collections of algae, cyanobacteria, and plant materials (cell cultures, hairy and adventitious root cultures, shoots, etc.) maintained in vitro or in liquid nitrogen (-196 °C, LN) are valuable sources of strains with unique ecological and biotechnological traits. Such collections play a vital role in bioresource conservation, science, and industry development but are rarely covered in publications. Here, we provide an overview of five genetic collections maintained at the Institute of Plant Physiology of the Russian Academy of Sciences (IPPRAS) since the 1950-1970s using in vitro and cryopreservation approaches. These collections represent different levels of plant organization, from individual cells (cell culture collection) to organs (hairy and adventitious root cultures, shoot apices) to in vitro plants. The total collection holdings comprise more than 430 strains of algae and cyanobacteria, over 200 potato clones, 117 cell cultures, and 50 strains of hairy and adventitious root cultures of medicinal and model plant species. The IPPRAS plant cryobank preserves in LN over 1000 specimens of in vitro cultures and seeds of wild and cultivated plants belonging to 457 species and 74 families. Several algae and plant cell culture strains have been adapted for cultivation in bioreactors from laboratory (5-20-L) to pilot (75-L) to semi-industrial (150-630-L) scale for the production of biomass with high nutritive or pharmacological value. Some of the strains with proven biological activities are currently used to produce cosmetics and food supplements. Here, we provide an overview of the current collections' composition and major activities, their use in research, biotechnology, and commercial application. We also highlight the most interesting studies performed with collection strains and discuss strategies for the collections' future development and exploitation in view of current trends in biotechnology and genetic resources conservation.

Optimization of Biomass and Secondary Metabolite Production in Gynura procumbens (Lour.) Merr. Adventitious Roots Culture by Using the Method of Subculture and Fed-batch Cultivation in a Bioreactor

The valuable extract of bioactive compounds from Gynura procumbens has been widely manufactured into various health products. The demand for these compounds is continuously increasing, but production through conventional farming methods is insufficient due to limited agricultural land and environmental stresses. An alternative to producing plant biomass is in vitro cultivation methods. This method requires less space and enables biomass propagation in a controlled condition that can facilitate stable and efficient production of plant secondary metabolites. This study evaluated the effect of inoculum subculture periods and culture methods on G. procumbens biomass and secondary metabolite production in a bioreactor. The 3-L airlift balloon type-bubble bioreactors was modified in this study to adopt the treatment of 1st-5th subculture periods and fed- and batch-cultivation strategies. We found the G. procumbens adventitious root culture was optimally derived from the 1st subculture produced biomass of 148.02±1.45 g FW and 8.59±0.12 g DW, and TPC (14.48±1.08 mg GAE/g DW) and TFC (116.89±0.44 mg KE/g DW and 33.97±0.13 mg QE/g DW). Additionally, the fed method after 28 days of culture using double distilled water replenishment improved adventitious root biomass (213.75±35.00 g FW and 11.21±0.18 g DW), while nutrient replenishment improved TFC (52.14±0.44 mg KE/g DW and 14.54±0.13 mg QE/g DW). These results can be used to optimize the cultivation of G. procumbens adventitious roots in a large-scale bioreactor.

Improving Flavonoid Accumulation of Bioreactor-Cultured Adventitious Roots in Oplopanax elatus Using Yeast Extract.

Oplopanax elatus is an endangered medicinal plant, and adventitious root (AR) culture is an effective way to obtain its raw materials. Yeast extract (YE) is a lower-price elicitor and can efficiently promote metabolite synthesis. In this study, the bioreactor-cultured O. elatus ARs were treated with YE in a suspension culture system to investigate the elicitation effect of YE on flavonoid accumulation, serving for further industrial production. Among YE concentrations (25-250 mg/L), 100 mg/L YE was the most suitable for increasing the flavonoid accumulation. The ARs with various ages (35-, 40-, and 45-day-old) responded differently to YE stimulation, where the highest flavonoid accumulation was found when 35-day-old ARs were treated with 100 mg/L YE. After YE treatment, the flavonoid content increased, peaked at 4 days, and then decreased. By comparison, the flavonoid content and antioxidant activities in the YE group were obviously higher than those in the control. Subsequently, the flavonoids of ARs were extracted by flash extraction, where the optimized extraction process was: 63% ethanol, 69 s of extraction time, and a 57 mL/g liquid-material ratio. The findings provide a reference for the further industrial production of flavonoid-enriched O. elatus ARs, and the cultured ARs have potential application for the future production of products.

Polyacetylenes from the adventitious roots of Centella asiatica with glucose uptake stimulatory activity.

Centella asiatica (L.) Urban is an herbaceous perennial plant of the Apiaceae family that has diverse medicinal uses. Its active components are saponin, phenolics, and polyacetylenes. Plant cell cultures have been exploited for the efficient production of metabolites with pharmacological activity. In this work, we prepared adventitious root cultures of C. asiatica and analyzed their content and biological activity. Adventitious root extracts were found to increase glucose uptake by differentiated L6 skeletal muscle cells and to be more efficient than the extract of whole plants. Chromatographic fractionation of the extracts from adventitious roots of C. asiatica led to the isolation of two known polyacetylenes, araliadiol (1) and 8-acetoxy-1,9-pentadecadiene-4,6-diyn-3-ol (2), in addition to a new polyacetylene, which we have named centellidiol (3). All the three polyacetylenes stimulated glucose uptake in a dose-dependent manner. The methanol extract of adventitious roots contained 0.53% and 0.82% of compounds 1 and 2, respectively, which are values that were 15 and 21 times higher that are found in mother plants. We therefore suggest that the high content of these polyacetylenes contributes to the high efficacy of C. asiatica adventitious root cultures. Overall, adventitious root cultures of C. asiatica can be part of a secure supply of effective ingredients including polyacetylenes.

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 100μM 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 3.34mg/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.