Galanthamine and Related Alkaloids Production by Leucojum aestivum L. Shoot Culture using a Temporary Immersion Technology

Do Vermicompost Applications Improve Growth Performance, Pharmaceutically Important Alkaloids, Phenolic Content, Free Radical Scavenging Potency and Defense Enzyme Activities in Summer Snowflake (Leucojum aestivum L.)?

Leucojum aestivum L. contains galanthamine and lycorine, which are two pharmaceutically valuable alkaloids. Vermicompost (VC), an organic waste product created by earthworms enhances soil quality and can improve the medicinal quality of the plant that is crucial to the pharmaceutical industry. The aim of this study was to determine the effects of four different VC concentrations (5 %, 10 %, 25 %, and 50 %) on L. aestivum growth parameters, alkaloid levels (galanthamine and lycorine), total phenol-flavonoid content, free radical scavenging potential, and defense enzyme activities (SOD and CAT) compared to control (no VC). The width, length, and fresh weight of the leaves were improved by 10 % VC treatment. The highest total phenolic content was found in the bulbs and leaves treated with 50 % VC. HPLC-DAD analysis of alkaloids showed that 10 % and 50 % VC treatments contained the most galanthamine in the bulb and leaf extracts, respectively. The application of 25 % VC was the most efficient in terms of lycorine content in both extracts. CAT activity was elevated at 10 %, 25 %, and 50 % VC. Based on the growth performance and galanthamine content of the bulbs and leaves, it can be concluded that a 10 % VC application was the most effective in the cultivation of L. aestivum.

Cultivation of Gardenia jasminoides shoots in temporary immersion systems and optimization of the immersion periods

In the present study, the effect of different immersion regimes on the growth and secondary metabolites production by shoot cultures of Gardenia jasminoides Ellis, cultivated in temporary immersion systems (TIS) was investigated. The cultivation was performed for 30 days on MS medium supplemented with 4.0 mg/L BAP. The regimes of cultivation included 15 min. immersion every 4, 8 and 12 hours. The highest amount of accumulated dry biomass (ADB = 10.86 ± 0.02 g/L) was reached at 15 min. immersion at every 8 hours, whereas the lowest (ADB = 4.65 ± 0.26 g/L) was recorded when 15 min. immersion on every 4 hours was used. HPLC analyses showed that the higher polyphenol content was achieved when shoots were cultivated by using 15 min. immersion on every 12 hours. At this conditions, the shoots produced maximal amounts of chlorogenic acid (164.82±32.36ug/g DW), caffeic acid (26,90±6,80μg/g DW), rutin (891,67±122,29μg/g DW) and rosmarinic acid (559,19±19,85μg/g DW). The observed antioxidant activity (DPPH, ABTS, CUPRAC and FRAP) was following the accumulation of total phenolic. The study demonstrates that TIS are effective for cultivation of Gardenia jasminoides shoots.

Temporary immersion systems (TISs): A comprehensive review

The temporary immersion systems (TISs) have been widely used in plant biotechnology. TISs have different advantages from the point of micropropagation and production of secondary metabolites over other continuous liquid-phase bioreactors. The current work presents the structure, operation mode, configuration type, and micropropagation or secondary metabolite production in TISs. This review deals with the advantages and disadvantages of TISs and the factors affecting their performance. Future research could focus on new designs based on CFD simulation, facilitating sterilization, and combining TISs with other bioreactors (e.g., mist bioreactors) to make a hybrid bioreactor.

Biotechnological Approaches to Optimize the Production of Amaryllidaceae Alkaloids

Amaryllidaceae alkaloids (AAs) are plant specialized metabolites with therapeutic properties exclusively produced by the Amaryllidaceae plant family. The two most studied representatives of the family are galanthamine, an acetylcholinesterase inhibitor used as a treatment of Alzheimer's disease, and lycorine, displaying potent in vitro and in vivo cytotoxic and antiviral properties. Unfortunately, the variable level of AAs' production in planta restricts most of the pharmaceutical applications. Several biotechnological alternatives, such as in vitro culture or synthetic biology, are being developed to enhance the production and fulfil the increasing demand for these AAs plant-derived drugs. In this review, current biotechnological approaches to produce different types of bioactive AAs are discussed.

Improving large-scale biomass and total alkaloid production of Dendrobium nobile Lindl. using a temporary immersion bioreactor system and MeJA elicitation

BACKGROUND

Dendrobium nobile Lindl. is an important pharmacopeial plant with medicinal and ornamental value. This study sought to provide a technical means for the large-scale production of total alkaloid in D. nobile. Seedlings were cultured in vitro using a temporary immersion bioreactor system (TIBS). The four tested immersion frequencies (min/h; 5/2, 5/4, 5/6, and 5/8) influenced the production of biomass and total alkaloid content. In addition, to compare the effects of different concentrations of the phytohormone methyl jasmonate (MeJA) and treatment time on biomass and total alkaloid accumulation, MeJA was added to the TIBS medium after 50 days. Finally, total alkaloid production in semi-solid system (SSS), TIBS, and TIBS combined with the MeJA system (TIBS-MeJA) were compared.

RESULTS

The best immersion frequency was found to be 5/6 (5 min every 6 h), which ensured appropriate levels of biomass and total alkaloid content in plantlets. The alkaloid content and production level of seedlings were the highest after treatment with 10 μM MeJA separately for 20 and 30 days using TIBS. The maximum content (7.41 mg/g DW) and production level (361.24 mg/L) of total alkaloid on use of TIBS-MeJA were 2.32- and 4.69-fold, respectively, higher in terms of content, and 2.07- and 10.49-fold, respectively, higher in terms of production level than those on using of TIBS (3.20 mg/g DW, 174.34 mg/L) and SSS (1.58 mg/g DW, 34.44 mg/L).

CONCLUSIONS

Our results show TIBS-MeJA is suitable for large-scale production of total alkaloid in in vitro seedlings. Therefore, this study provides a technical means for the large-scale production of total alkaloid in D. nobile.

Recent Progress in Amaryllidaceae Biotechnology

Plants belonging to the monocotyledonous Amaryllidaceae family include about 1100 species divided among 75 genera. They are well known as medicinal and ornamental plants, producing pharmaceutically important alkaloids, the most intensively investigated of which are galanthamine and lycorine. Amaryllidaceae alkaloids possess various biological activities, the most important one being their anti-acetylcholinesterase activity, used for the treatment of Alzheimer's disease. Due to increased demand for Amaryllidaceae alkaloids (mainly galanthamine) and the limited availability of plant sources, in vitro culture technology has attracted the attention of researchers as a prospective alternative for their sustainable production. Plant in vitro systems have been extensively used for continuous, sustainable, and economically viable production of bioactive plant secondary metabolites. Over the past two decades, a significant success has been demonstrated in the development of in vitro systems synthesizing Amaryllidaceae alkaloids. The present review discusses the state of the art of in vitro Amaryllidaceae alkaloids production, summarizing recently documented plant in vitro systems producing them, as well as the authors' point of view on the development of biotechnological production processes with a focus on the future prospects of in vitro culture technology for the commercial production of these valuable alkaloids.

Carbohydrates stimulated Amaryllidaceae alkaloids biosynthesis in Leucojum aestivum L. plants cultured in RITA® bioreactor

Background

Leucojum aestivum L. is an important medicinal plant which produces Amaryllidaceae alkaloids, especially galanthamine and lycorine. Research is currently exploring the possibility of producing these alkaloids using biotechnological methods, including in vitro cultures. The biosynthesis of alkaloids may be affected by the types and concentrations of carbohydrate sources used in the medium. In the present investigation we performed such studies on in vitro cultures of L. aestivum with a view to obtaining plant material of good quality, characterized, in particular, by a high content of valuable Amaryllidaceae alkaloids.

Methods

We examined the effects of various types of carbohydrate sources—sucrose, glucose, fructose and maltose—at different concentrations (30, 60 and 90 g/L)—on the quality of L. aestivum plants grown in the RITA^® bioreactor. The plants’ quality was assessed by their biomass increments, as well by as analysing photosynthetic pigments, endogenous sugar, phenolics and Amaryllidaceae alkaloid content. We also investigated the effect of sugars on the activity of the antioxidant enzymes catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD).

Results

The highest biomass increments were observed in plants cultivated in the medium containing 90 g/L sucrose. The highest CAT activity was noted in cultures growing in the medium supplemented with 90 g/L maltose, while the highest POD activity was observed in the presence of 90 g/L fructose and 60 g/L maltose. No differences in SOD activity were observed. Moreover, the sugars did not affect the contents of chlorophyll a and carotenoids, whereas the highest amount of chlorophyll b was recorded in plants growing in the medium with 60 g/L maltose. No statistically significant differences were observed in the contents of endogenous sugars and phenolics in any in vitro conditions. However, the addition of sugar had a decisive effect on the biosynthesis of the Amaryllidaceae alkaloids. The highest distribution of alkaloids occurred in plants cultured in the medium containing 60 g/L sucrose. Six Amaryllidaceae alkaloids were detected in the plant tissue. The addition of 30 g/L fructose in the medium resulted in the accumulation of five alkaloids, including ismine, which was not identified in other analysed tissues. The highest concentration of galanthamine was observed in plants cultured in the presence of 30 g/L fructose and 60 g/L sucrose (39.2 and 37.5 µg/g of dry weight (DW), respectively). The plants grown in the medium containing 60 g/L sucrose exhibited the highest lycorine content (1048 µg/g of DW).

Conclusions

The type and concentration of sugar used in the medium have an essential influence on the biosynthesis of Amaryllidaceae alkaloids in L. aestivum plants cultured in a RITA^® bioreactor. The results point to an interesting approach for commercial production of galanthamine and lycorine.

In sito galanthamine extraction during the cultivation of Leucojum aestivum L. shoot culture in two-phase bubble column cultivation system

Two‐phase bioreactor cultivation system was developed and applied for in sito recovery of extracellular galanthamine during the cultivation of Leucojum aestivum L. shoot culture in a modified column bioreactor system. The inclusion of an external circulation column with adsorbent resin Amberlite XAD‐4 as a second phase, on the 21st day of the beginning of cultivation resulted in 1.25 folds increase in biomass accumulation and maximal amounts of accumulated galanthamine of 6 mg/L (3.1 mg/L intracellular and 2.9 mg/L extracellular). It was demonstrated that the inclusion of a second phase at the cultivation of the L. aestivum shoot culture in a bubble column bioreactor with internal sections redirected the alkaloid metabolism to galanthamine synthesis and inhibits the synthesis of hemanthamine and lycorine type alkaloids. Our research demonstrated that the application of the two‐phase cultivation systems could be an important tool to increase the yields of valuable secondary metabolites in plant tissue culture‐based bioprocess.

Developmental Regulation of the Expression of Amaryllidaceae Alkaloid Biosynthetic Genes in Narcissus papyraceus

Amaryllidaceae alkaloids (AAs) have multiple biological effects, which are of interest to the pharmaceutical industry. To unleash the potential of Amaryllidaceae plants as pharmaceutical crops and as sources of AAs, a thorough understanding of the AA biosynthetic pathway is needed. However, only few enzymes in the pathway are known. Here, we report the transcriptome of AA-producing paperwhites (Narcissus papyraceus Ker Gawl). We present a list of 21 genes putatively encoding enzymes involved in AA biosynthesis. Next, a cDNA library was created from 24 different samples of different parts at various developmental stages of N. papyraceus. The expression of AA biosynthetic genes was analyzed in each sample using RT-qPCR. In addition, the alkaloid content of each sample was analyzed by HPLC. Leaves and flowers were found to have the highest abundance of heterocyclic compounds, whereas the bulb, the lowest. Lycorine was also the predominant AA. The gene expression results were compared with the heterocyclic compound profiles for each sample. In some samples, a positive correlation was observed between the gene expression levels and the amount of compounds accumulated. However, due to a probable transport of enzymes and alkaloids in the plant, a negative correlation was also observed, particularly at stage 2.

Leucojum aestivum L. in vitro bulbs induction and acclimatization

The effects of growth retardants (paclobutrazol and ancymidol), sucrose, GA3 (gibberellic acid) and physical state of the medium (solid and liquid — Rita® temporary immersion system) on in vitro induction of Leucojum aestivum bulbs and their acclimatization were studied. Paclobutrazol, regardless of the physical state of the medium, stimulated the formation of bulbs (99.3%). Under the influence 90 g L−1 of sucrose or paclobutrazol the bulbs with the highest fresh weight (FW) were formed (250 mg and 208.8 mg, respectively). However, the addition of ancymidol to the liquid medium led to obtaining the bulbs showing the highest number of leaves and roots (63.2% and 91.7%, respectively). The scanning microscopy study proved that plants obtained in the medium containing GA3 produced the stomata which most closely resembled to the one observed in the mother plant. Cytometric analysis of all regenerants revealed absence of changes in the nuclear DNA content. The maximum survival rate (100%) was observed for plants derived from liquid medium containing 90 g L−1 of sucrose. Somewhat fewer plants were acclimatized after their cultivations in liquid medium enriched with paclobutrazol or ancymidol. The temporary immersion system led to perform successful ex vitro adaptation of Leucojum aestivum plants.

Elicitation of galanthamine biosynthesis by Leucojum aestivum liquid shoot cultures

The effects of methyl jasmonate and jasmonic acid on galanthamine production, phenolic acid content and growth of Leucojum aestivum L. shoot culture, cultivated in submerged conditions were investigated. The best time-point for addition of elicitors was during the exponential phase of the culture growth. The maximal contents of galanthamine and lycorine (226.9 μg/flask and 491.4 μg/flask, 1.36 and 1.67-fold higher compared to the control, respectively) were achieved after elicitation with jasmonic acid, whereas the elicitation with methyl jasmonte resulted in maximal accumulation of phenolic acids. It was demonstrated that the boosting effect of jasmonic acid on Amaryllidacea alkaloid biosynthesis was due to induction of the activity of tyrosine decarboxylase, whereas methyl jasmonate stimulates the biosynthesis of phenolic acids by inducing mainly the activity of phenylalanine ammonia-lyase.

Amaryllidaceae and Sceletium alkaloids

Covering: July 2010 to June 2012. Previous review: Nat. Prod. Rep., 2011, 28, 1126-1142. Recent progress on the isolation, identification, biological activity and synthetic studies of structurally diverse alkaloids from plants of the family Amaryllidaceae is summarized in this review. In addition, the structurally related alkaloids isolated from Sceletium species are discussed as well.

Influence of auxins on somatic embryogenesis and alkaloid accumulation in Leucojum aestivum callus

In vitro cultures of Leucojum aestivum are considered as an alternative for the production of galanthamine, which is used for the symptomatic treatment of Alzheimer’s disease. We studied the effects of auxins 2,4-dichlorophenoxyacetic acid (2,4-D), 4-amino-3,5,6-trichloropicolinic acid (picloram), 3,6-dichloro-o-anisic acid (dicamba) at concentrations of 25 and 50 µM on the induction of embryogenic callus and its capacity to induce somatic embryogenesis and alkaloid accumulation. The embryogenic response of the explants was from 30% for 25 µM of dicamba to 100% for picloram (for both 25 and 50 µM). 2,4-D (50 µM) stimulated greater callus proliferation and somatic embryo induction as compared to the other auxins. Polyethylene glycol (PEG) stimulated somatic embryo maturation. Callus grown on media containing 50 µM of auxins produced fewer phenolic compounds as compared with callus grown on media containing 25 µM of auxins. GC-MS analyses showed seven alkaloids in the in vivo bulbs and two to four in callus culture. Galanthamine was detected in callus cultivated with 2,4-D (25, 50 µM), picloram (25 µM), and dicamba (50 µM). Other alkaloids, trisphaeridine, tazettine, and 11-hydroxyvittatine were accumulated only in callus growing on medium with picloram (50 µM).

Hosting the plant cells in vitro: recent trends in bioreactors

Biotechnological production of high-value metabolites and therapeutic proteins by plant in vitro systems has been considered as an attractive alternative of classical technologies. Numerous proof-of-concept studies have illustrated the feasibility of scaling up plant in vitro system-based processes while keeping their biosynthetic potential. Moreover, several commercial processes have been established so far. Though the progress on the field is still limited, in the recent years several bioreactor configurations has been developed (e.g., so-called single-use bioreactors) and successfully adapted for growing plant cells in vitro. This review highlights recent progress and limitations in the bioreactors for plant cells and outlines future perspectives for wider industrialization of plant in vitro systems as "green cell factories" for sustainable production of value-added molecules.

Production of galanthamine by Leucojum aestivum shoots grown in different bioreactor systems

The production of galanthamine by shoots of Leucojum aestivum grown in different bioreactor systems (shaking and nonshaking batch culture, temporary immersion system, bubble bioreactor, continuous and discontinuous gassing bioreactor) under different culture conditions was studied. The influence of the nutrient medium, weight of inoculum, and size of bioreactor on both growth and galanthamine production was studied. The maximal yield of galanthamine (19.416 mg) was achieved by cultivating the L. aestivum shoots (10 g of fresh inoculum) in a temporary immersion system in a 1-L bioreactor vessel which was used as an airlift culture vessel, gassing 12 times per day (5 min).

Alkaloid patterns in Leucojum aestivum shoot culture cultivated at temporary immersion conditions

The alkaloid patterns in Leucojum aestivum L. shoot culture cultivated at temporary immersion conditions were investigated using gas chromatography-mass spectrometry. 18 alkaloids were identified, and galanthamine, hamayne and lycorine were dominant. The L. aestivum 80 shoot culture, cultivated at temporary immersion conditions, is a prospective biological matrix for obtaining wide range Amaryllidaceae alkaloids, showing valuable biological and pharmacological activities. The temperature of cultivation influenced enzyme activities, catalyzing phenol oxidative coupling of 4'-O-methylnorbelladine and formation of the different groups Amaryllidaceae alkaloids. Decreasing the temperature of cultivation of L. aestivum 80 shoot culture led to activation of para-ortho' phenol oxidative coupling (formation of galanthamine type alkaloids) and inhibited ortho-para' and para-para' phenol oxidative coupling (formation of lycorine and haemanthamine types alkaloids).

Two-phase temporary immersion system for Agrobacterium rhizogenes genetic transformation of sage (Salvia tomentosa Mill.)

Hairy root cultures of Salvia tomentosa were initiated by transformation with Agrobacterium rhizogenes. To prevent necrosis in the explants and to protect young hairy roots, Amberlite XAD-4 resin, in combination with a temporary immersion cultivation system, was applied. HPLC analyzes showed that the resin adsorbed more than 93% of the released phenolic acids and 100% of the released flavonoids. The decreased content of the released phenolics significantly reduced their destructive effects on the plant tissues, prevented, and speeded up the appearance of hairy roots.