Induced accumulation of oleanolic acid and ursolic acid in cell suspension cultures of Uncaria tomentosa

Plant In Vitro Culture Factories for Pentacyclic Triterpenoid Production

Pentacyclic triterpenoids are a diverse subclass of naturally occurring terpenes with various biological activities and applications. These compounds are broadly distributed in natural plant resources, but their low abundance and the slow growth cycle of plants pose challenges to their extraction and production. The biosynthesis of pentacyclic triterpenoids occurs through two main pathways, the mevalonic acid (MVA) pathway and the 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway, which involve several enzymes and modifications. Plant in vitro cultures, including elicited and hairy root cultures, have emerged as an effective and sustainable system for pentacyclic triterpenoid production, circumventing the limitations associated with natural plant resources. Bioreactor systems and controlling key parameters, such as media composition, temperature, light quality, and elicitor treatments, have been optimized to enhance the production and characterization of specific pentacyclic triterpenoids. These systems offer a promising bioprocessing tool for producing pentacyclic triterpenoids characterized by a low carbon footprint and a sustainable source of these compounds for various industrial applications.

Seasonal variations of triterpene acid contents in Viscum album L. on typical host trees of Hyrcanian forests

Viscum album L. (mistletoe) is a semiparasitic plant of the Santalaceae family. A valuable group of bioactive compounds in mistletoe are triterpene acids (TTAs), which possess anti-inflammatory and anticancer properties. Parrotia persica and Carpinus betulus are the most common hosts of mistletoe in the Hyrcanian forests of Iran. This study was performed to compare the content of oleanolic acid (OA), betulinic acid (BA), and ursolic acid (UA) in the mistletoe foliage (stems and leaves) from P. persica and C. betulus in various seasons for the first time. The results showed that OA was the prevailing TTA in all samples, while UA was found in none of them. The maximum amount of OA (12.38 mg/g dry weight [DW]) and BA (1.68 mg/g DW) was detected in V. album from P. persica in summer. The minimum amount of OA (5.58 mg/g DW) and BA (0.72 mg/g DW) was observed in that growing on C. betulus in winter. However, the mistletoe from C. betulus showed the greatest level of OA in spring (9.06 mg/g DW) and BA in summer and autumn (0.92 and 0.97 mg/g DW, respectively). The data collected in this study complement existing research on this subject from around the world.

Effect of Inoculum Size and Age, and Sucrose Concentration on Cell Growth to Promote Metabolites Production in Cultured Taraxacum officinale (Weber) Cells

Pentacyclic triterpenes, including lupeol, α- amyrin, and β-amyrin, present a large range of biological activities including anti-inflammatory, anti-cancer, and gastroprotective properties. The phytochemistry of dandelion (Taraxacum officinale) tissues has been widely described. Plant biotechnology offers an alternative for secondary metabolite production and several active plant ingredients are already synthesized through in vitro cultures. This study aimed to establish a suitable protocol for cell growth and to determine the accumulation of α-amyrin and lupeol in cell suspension cultures of T. officinale under different culture conditions. To this end, inoculum density (0.2% to 8% (w/v)), inoculum age (2- to 10-week-old), and carbon source concentration (1%, 2.3%, 3.2%, and 5.5% (w/v)) were investigated. Hypocotyl explants of T. officinale were used for callus induction. Age, size, and sucrose concentrations were statistically significant in cell growth (fresh and dry weight), cell quality (aggregation, differentiation, viability), and triterpenes yield. The best conditions for establishing a suspension culture were achieved by using a 6-week-old callus at 4% (w/v) and 1% (w/v) of sucrose concentration. Results indicate that 0.04 (±0.02) α-amyrin and 0.03 (±0.01) mg/g lupeol can be obtained in suspension culture under these starting conditions at the 8th week of culture. The results of the present study provide a backdrop for future studies in which an elicitor could be incorporated to increase the large-scale production of α-amyrin and lupeol from T. officinale.

Methyl Jasmonate and Salicylic Acid Enhanced the Production of Ursolic and Oleanolic Acid in Callus Cultures of Lepechinia Caulescens

Background

The production of triterpenes from plants for pharmacological purposes varies in concentration, due to genetic and environmental factors. In vitro culture enables the control and increase of these bioactive molecules.

Objective

To evaluate the effect of plant growth regulators and elicitors in the induction of calli and the production of ursolic acid (UA) and oleanolic acid (OA) in Lepechinia caulescens.

Materials and Methods

Leaf explants were exposed for the induction of calli at different concentrations and combinations of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). Methyl jasmonate (MJ) and salicylic acid were used as elicitors. High-performance liquid chromatography method was used to quantify UA and OA content in each treatment.

Results

Treatment with 3.0 mg/L of 2,4-D and 0.1 mg/L of BAP produced the best results for calli induction and production of UA (1.57 mg/g dry weight [DW]) and OA (1.13 mg/g DW). Both elicitors facilitated the accumulation of triterpenes.

Conclusion

The combination of auxins and cytokinins showed favorable results for the induction of calli. Variation concerning the accumulation of UA and OA was observed between treatments. MJ increased the production of triterpenes five times after 8 h of exposure, compared to control treatment. There is a greater accumulation of UA (16.58 mg/g DW) and OA (1.94 mg/g DW) in leaves of wild plants.

SUMMARY

Callus cultures of Lepechinia caulescens were obtained from leaf explants treated with 2,4-dichlorophenoxyacetic acid and 6-bencylaminopurineResulting cultures were elicited with methyl jasmonate (MJ) and salicylic acid to increase the production of the triterpenes, ursolic acid (UA), and oleanolic acid (OA)The cultures elicited with MJ increased the production of UA and OA five times, as compared to the control. Abbreviations used: 2,4-D: 2,4-dichlorophenoxyacetic acid, BAP: 6-benzylaminopurine, DW: Dry weight, MJ: Methyl jasmonate, OA: Oleanolic acid, PGRs: Plant growth regulators, UA: Ursolic acid, SA: Salicylic acid.

Natural products against Alzheimer's disease: Pharmaco-therapeutics and biotechnological interventions

Alzheimer's disease (AD) is a severe, chronic and progressive neurodegenerative disease associated with memory and cognition impairment ultimately leading to death. It is the commonest reason of dementia in elderly populations mostly affecting beyond the age of 65. The pathogenesis is indicated by accumulation of the amyloid-beta (Aβ) plaques and neurofibrillary tangles (NFT) in brain tissues and hyperphosphorylation of tau protein in neurons. The main cause is considered to be the formation of reactive oxygen species (ROS) due to oxidative stress. The current treatment provides only symptomatic relief by offering temporary palliative therapy which declines the rate of cognitive impairment associated with AD. Inhibition of the enzyme acetylcholinesterase (AChE) is considered as one of the major therapeutic strategies offering only symptomatic relief and moderate disease-modifying effect. Other non-cholinergic therapeutic approaches include antioxidant and vitamin therapy, stem cell therapy, hormonal therapy, use of antihypertensive or lipid-lowering medications and selective phosphodiesterase (PDE) inhibitors, inhibition of β-secretase and γ-secretase and Aβ aggregation, inhibition of tau hyperphosphorylation and intracellular NFT, use of nonsteroidal anti-inflammatory drugs (NSAIDs), transition metal chelators, insulin resistance drugs, etanercept, brain-derived neurotrophic factor (BDNF) etc. Medicinal plants have been reported for possible anti-AD activity in a number of preclinical and clinical trials. Ethnobotany, being popular in China and in the Far East and possibly less emphasized in Europe, plays a substantial role in the discovery of anti-AD agents from botanicals. Chinese Material Medica (CMM) involving Chinese medicinal plants has been used traditionally in China in the treatment of AD. Ayurveda has already provided numerous lead compounds in drug discovery and many of these are also undergoing clinical investigations. A number of medicinal plants either in their crude forms or as isolated compounds have exhibited to reduce the pathological features associated with AD. In this present review, an attempt has been made to elucidate the molecular mode of action of various plant extracts, phytochemicals and traditional herbal formulations investigated against AD as reported in various preclinical and clinical tests. Herbal synergism often found in polyherbal formulations were found effective to combat disease heterogeneity as found in complex pathogenesis of AD. Finally a note has been added to describe biotechnological improvement, genetic and genomic resources and mathematical and statistical techniques for empirical model building associated with anti-AD plant secondary metabolites and their source botanicals.

"Fungal elicitors combined with a sucrose feed significantly enhance triterpene production of a Salvia fruticosa cell suspension"

Oleanolic (OA) and ursolic acid (UA) are plant secondary metabolites with diverse pharmacological properties. To reach reasonable productivities with plant cell suspension cultures, elicitation is a widely used strategy. Within the presented work, the effects of different elicitors on growth and production of OA and UA in a Salvia fruticosa cell suspension culture were examined. Beside commonly used elicitors like jasmonic acid (JA) and yeast extract, the influence of medium filtrates of the endophytic fungi Aspergillus niger and Trichoderma virens was investigated. The best eliciting effects were achieved with JA and fungal medium filtrates. Both increased the triterpene content by approximately 70 %. Since JA showed significant growth inhibition, the volumetric triterpene yield did not increase. But, adding fungal filtrates increased the volumetric triterpene yield by approximately 70 % to 32.6 mgOA l(-1) and 65.9 mgUA l(-1) for T. virens compared to the control with 19.4 mgOA l(-1) and 33.3 mgUA l(-1). An elicitation strategy combining fungal medium filtrate of T. virens with sucrose feeding significantly enhanced cell dry weight concentration to 22.2 g l(-1) as well as triterpene content by approximately 140 %. In total, this led to an approximately 500 % increase of volumetric triterpene yield referring to the control with final values of 112.9 mgOA l(-1) and 210.4 mgUA l(-1). Despite the doubled cultivation duration, productivities of 6.7 mgOA l(-1) day(-1) and 12.4 mgUA l(-1) day(-1) were reached. These results demonstrate methods by which increased productivities of triterpenes can be achieved to attain yields competing with intact plants.

Production of anti-cancer triterpene (betulinic acid) from callus cultures of different Ocimum species and its elicitation

Betulinic acid (BA), a pentacyclic triterpenoid, is gaining unmatched attention owing to its unique anti-cancer activity with selective melanoma growth inhibition without damaging normal cells. It is also well-known for its multifaceted pharmacokinetics, entailing antibacterial, antimalarial, anti-HIV and antioxidant merits. Considering the escalating demand with diminishing bioresource of this molecule, the present study was undertaken that revealed the untapped potentials of Ocimum calli, contrasting to that in the in vitro derived leaves, as effective production alternative of BA in three out of four tested species (i.e. Ocimum basilicum, Ocimum kilimandscharicum, Ocimum sanctum excluding Ocimum grattisimum). Callus inductions were obtained in all the four species with different 2,4-dichlorophenoxyacetic acid (2,4-D)/α-naphthaleneacetic acid (NAA) concentrations with kinetin. Notably, 2,4-D favoured maximum callus growth in all whereas NAA proved beneficial for the highest metabolite yield in the calli of each BA-producing species. The O. basilicum calli demonstrated the maximum growth (growth index (GI) 678.7 ± 24.47) and BA yield (2.59 ± 0.55 % dry weight [DW]), whereas those in O. kilimandscharicum (GI 533.33 ± 15.87; BA 1.87 ± 0.6 % DW) and O. sanctum (GI 448 ± 16.07; BA 0.39 ± 0.12 % DW) followed a descending order. The O. gratissimum calli revealed minimum growth (GI 159 ± 13.25) with no BA accumulation. Elicitation with methyl jasmonate at 200-μM concentration after 48-h exposure doubled the BA yield (5.10 ± 0.18 % DW) in NAA-grown O. basilicum calli compared to that in the untreated counterpart (2.61 ± 0.19 % DW), which further enthused its future application.

Regulation and improvement of triterpene formation in plant cultured cells of Eriobotrya japonica Lindl

Loquat (Eriobotrya japonica Lindl) is a traditional Chinese medicinal plant that contains triterpenes, which have been shown to exhibit pharmaceutical activities. In this study, we investigated various different culture conditions for cultured cells of loquat to produce triterpenes, including illumination, carbon source, nutrient composition and culture system. When cultured on 2.5mg/l of 6-benzyladenine, 1mg/l of naphthalene acetic acid and 30 g/l of sucrose at 25 ± 2 °C in the dark for 30 days, the nutrient composition significantly regulated the cell growth and triterpene production. Supplied with the Murashige and Skoog medium reached higher level of dry weight (1.27 ± 0.09 g per flask) and total triterpene production (151.54 ± 12.58 mg/g of cultured cells), and the N6 medium produced tormentic acid but inhibited other triterpene products, while the B5 medium produced relatively high corosolic acid. Also found, suspension cultures of loquat cell could achieve high productivity as callus culture.