Foliar application of elicitors enhanced the yield of withanolide contents in Withania somnifera (L.) Dunal (variety, Poshita)

A critical assessment of the whole plant-based phytotherapeutics from Withania somnifera (L.) Dunal with respect to safety and efficacy vis-a-vis leaf or root extract-based formulation

Withania somnifera (L.) Dunal, popularly known as Ashwagandha or Indian ginseng, is well acclaimed for its health-enhancing effects, including its potent immunomodulatory, anti-inflammatory, neuroprotective, and anti-tumorigenic properties. The prime biological effectors of these attributes are a diverse group of ergostane-based steroidal lactones termed withanolides. Withanones and withanosides are distributed differentially across the plant body, whereas withanolides and withanones are known to be more abundant in leaves, while withanosides are found exclusively in the roots of the plants. Standardized W. somnifera extract is Generally Recognized as Safe (GRAS)-affirmed, however, moderate to severe toxic manifestations may occur at high dosages. Withaferin A, which also happens to be the primary bioactive ingredient for the effectiveness of this plant. There have been contrasting reports regarding the distribution of withaferin A in W. somnifera. While most reports state that the roots of the plant have the highest concentrations of this phytochemical, several others have indicated that leaves can accumulate withaferin A in proportionately higher amounts. A comprehensive survey of the available reports suggests that the biological effects of Ashwagandha are grossly synergistic in nature, with many withanolides together mediating the desired physiological effect. In addition, an assorted formulation of withanolides can also neutralize the toxic effects (if any) associated with withaferin A. This mini-review presents a fresh take on the recent developments regarding the safety and toxicity of the plant, along with a critical assessment of the use of roots against leaves as well as whole plants to develop therapeutic formulations. Going by the currently available scientific evidence, it is safe to infer that the use of whole plant formulations instead of exclusively root or leaf recipes may present the best possible option for further exploration of therapeutic benefits from this novel medicinal plant.HighlightsTherapeutic potential of withanolides owes to the presence of α,β unsaturated ketone which binds to amines, alcohols, and esters and 5β, 6β epoxy group which react with side chain thiols of proteins.At concentrations above NOAEL (no observed adverse effect level), the same mechanisms contribute towards toxicity of the molecule.Although withanosides are found exclusively in roots, whole plants have higher contents of withanones and withanolides.Whole plant-based formulations have other metabolites which can nullify the toxicity associated with roots.Extracts made from whole plants, therefore can holistically impart all therapeutic benefits as well as mitigate toxicity.

Estimating the production of withaferin A and withanolide A in Withania somnifera (L.) dunal using aquaponics for sustainable development in hill agriculture

Introduction

Humanity is suffering from huge and severe difficulties, including changes in climate, soil degradation, scarcity of water and the security of food and medicines, among others. The aquaponics system acts as a closed loop consisting of aquaculture elements and hydroponics, which may contribute to addressing these problems. The aquaponics method is quickly expanding as the requirement to increase the production of sustainable herbal products, including medicinal compounds and foods, in freshwater systems and replenish phosphorous reserves shrinks.

Methods

The current work is designed to increase the production of the antioxidants withaferin A and withanolide A in two varieties (Jawahar-20 and Poshita) of W. somnifera using the aquaponics technique. Total 100 seedlings (one month old) grown in soil initially were taken to be grown in aquaponics for a time period of 6 months.And 100 seedlings were placed in pots containing soil as control for study after six months.

Results

It was observed that the higher content of withaferin A was analyzed in the root and stem samples of Jawahar-20 and Poshita from the six-month-old plant of W. somnifera. The maximum content of withanolide A was examined in the root samples of the six month-old plants of Poshita (1.879 mg/g) and Jawahar-20 (1.221 mg/g). While the 6 month old Poshita seedling grown in soil recorded less withaferin A (0.115 ± 0.009b) and withanolide A (0.138 ± 0.008d).

Discussion

It is concluded that Poshita was found to be more promising for the enhanced production of withaferin A and withanolide A in the aquaponics system. Moreover, the root was observed as the best source for the production of withaferin A and withanolide A and the best age of the plant is 2 years for the production compounds in medicinal plants with futuristic perspective to hill agriculture integrated farming. compounds. Thus aquaponics can be an effective approach with enhanced yield of bioactive compounds in medicinal plants with futuristic perspective to hill agriculture and integrated farming.

Optimization of Elicitation Conditions to Enhance the Production of Potent Metabolite Withanolide from Withania somnifera (L.)

This study aimed at optimizing conditions for increased withanolide production in Withania somnifera. The elicitors used for the foliar spray on the aerial parts of the plant were salicylic acid, jasmonic acid, and chitosan for the enhancement of withanolides in Withania somnifera under different environmental regimes. Three different elicitors, i.e., chitosan, jasmonic acid and salicylic acid, were applied on the plants through foliar route every 15th day for 6 months, and later plants were used for sample preparation. Further, the elicitors were used in different concentration, i.e., jasmonic acid (50, 200 and 400 ppm), chitosan (10, 50 and 100 ppm) and salicylic acid (0.5, 1 and 2 ppm). The elicitors were sprayed on the foliar parts of the plant between 10:00-11:00 a.m. on application days. For elicitor spray, a calibrated sprayer was used. The withanolide A/withaferin A was quantified through HPLC. It was found that in an open environment, maximum withaferin A content, i.e., 0.570 mg/g (DW), was recorded with jasmonic acid (50 ppm) treatment in comparison to control (0.067 mg/g DW). Thus, there was an 8.5-fold increase in the withaferin A content. Maximum withanolide A content of 0.352 mg/g (DW) was recorded when chitosan (50 ppm) was sprayed, while in the control, withanolide A content was recorded to be 0.031 mg/g (DW); thus, chitosan application increased the production of withanolide A by 11.3-fold. Under controlled conditions, maximum withaferin A content of 1.659 mg/g (DW) was recorded when plants were sprayed with chitosan (100 ppm), which was 8.1 times greater than the control content of 0.203 mg/g (DW). Maximum withanolide A content of 0.460 mg/g (DW) was recorded when chitosan (100 ppm) was applied, whereas in the control, withanolide A content was found to be 0.061 mg/g (DW). Thus, foliar spraying of elicitors in very low concentrations can serve as a low-cost, eco-friendly, labor-intensive and elegant alternative approach that can be practiced by farmers for the enhancement, consistent production and improved yield of withanolide A/withaferin A. This can be a suitable way to enhance plant productivity, thus increasing the availability of withanolide A and withaferin A for the health and pharma industry.

Jasmonates in plant growth and development and elicitation of secondary metabolites: An updated overview

Secondary metabolites are incontestably key specialized molecules with proven health-promoting effects on human beings. Naturally synthesized secondary metabolites are considered an important source of pharmaceuticals, food additives, cosmetics, flavors, etc., Therefore, enhancing the biosynthesis of these relevant metabolites by maintaining natural authenticity is getting more attention. The application of exogenous jasmonates (JAs) is well recognized for its ability to trigger plant growth and development. JAs have a large spectrum of action that covers seed germination, hypocotyl growth regulation, root elongation, petal expansion, and apical hook growth. This hormone is considered as one of the key regulators of the plant's growth and development when the plant is under biotic or abiotic stress. The JAs regulate signal transduction through cross-talking with other genes in plants and thereby deploy an appropriate metabolism in the normal or stressed conditions. It has also been found to be an effective chemical elicitor for the synthesis of naturally occurring secondary metabolites. This review discusses the significance of JAs in the growth and development of plants and the successful outcomes of jasmonate-driven elicitation of secondary metabolites including flavonoids, anthraquinones, anthocyanin, xanthonoid, and more from various plant species. However, as the enhancement of these metabolites is essentially measured via in vitro cell culture or foliar spray, the large-scale production is significantly limited. Recent advancements in the plant cell culture technology lay the possibilities for the large-scale manufacturing of plant-derived secondary metabolites. With the insights about the genetic background of the metabolite biosynthetic pathway, synthetic biology also appears to be a potential avenue for accelerating their production. This review, therefore, also discussed the potential manoeuvres that can be deployed to synthesis plant secondary metabolites at the large-scale using plant cell, tissue, and organ cultures.

Traditional in vitro strategies for sustainable production of bioactive compounds and manipulation of metabolomic profile in medicinal, aromatic and ornamental plants

Precursor feeding, elicitation and culture medium parameters are traditional in vitro strategies to enhance bioactive compounds of medicinal, aromatic, and ornamental plants (MAOPs). Machine learning can help researchers find the best combination of these strategies to increase the secondary metabolites content of MAOPs. Many requirements for human life, from food, pharmaceuticals and cosmetics to clothes, fuel and building materials depend on plant-derived natural products. Essential oils, methanolic and ethanolic extracts of in vitro undifferentiated callus and organogenic cultures of medicinal, aromatic, and ornamental plants (MAOPs) contain bioactive compounds that have several applications for various industries, including food and pharmaceutical. In vitro culture systems provide opportunities to manipulate the metabolomic profile of MAOPs. Precursors feeding, elicitation and culture media optimization are the traditional strategies to enhance in vitro accumulation of favorable bioactive compounds. The stimulation of plant defense mechanisms through biotic and abiotic elicitors is a simple way to increase the production of secondary metabolites in different in vitro culture systems. Different elicitors have been applied to stimulate defense machinery and change the metabolomic profile of MAOPs in in vitro cultures. Plant growth regulators (PGRs), stress hormones, chitosan, microbial extracts and physical stresses are the most applied elicitors in this regard. Many other chemical tolerance-enhancer additives, such as melatonin and proline, have been applied along with stress response-inducing elicitors. The use of stress-inducing materials such as PEG and NaCl activates stress tolerance elicitors with the potential of increasing secondary metabolites content of MAOPs. The present study reviewed the state-of-the-art traditional in vitro strategies to manipulate bioactive compounds of MAOPs. The objective is to provide insights to researchers involved in in vitro production of plant-derived natural compounds. The present review provided a wide range of traditional strategies to increase the accumulation of valuable bioactive compounds of MAOPs in different in vitro systems. Traditional strategies are faster, simpler, and cost-effective than other biotechnology-based breeding methods such as genetic transformation, genome editing, metabolic pathways engineering, and synthetic biology. The integrate application of precursors and elicitors along with culture media optimization and the interpretation of their interactions through machine learning algorithms could provide an excellent opportunity for large-scale in vitro production of pharmaceutical bioactive compounds.

Alteration of resveratrol-dependent glycosyltransferase activity by elicitation in DJ-526 rice

Since the successful creation of DJ-526, a resveratrol-enriched rice cultivar, research has focused on resveratrol production because of its great potential in pharmaceutical applications. However, the utilization of resveratrol in DJ-526 is limited by glycosylation, which converts resveratrol to its glucoside (piceid), in a process driven by glycosyltransferase. The verification of resveratrol-dependent glycosyltransferase activity is an essential strategy for improving resveratrol production in DJ-526 rice. In this study, 27 candidate glycosyltransferases were evaluated in germinated seeds. Among the candidates, only R12 exhibited upregulation related to increased resveratrol and piceid content during seed germination, whereas various effects on the activity of glycosyltransferase were observed by the presence of a bio-elicitor. Yeast extract tended to enhance glycosyltransferase activity by seven candidates, and a specific peak for an unknown compound production was identified. Conversely, chitosan acted as a glycosyltransferase inhibitor. Our results suggested that R12 and R19 are the most relevant candidate resveratrol-dependent glycosyltransferases in DJ-526 seeds during germination and elicitation. Future research should assess the possibility of silencing these candidate genes in an effort to improve resveratrol levels in DJ-526 rice.

Chitosan Induces Plant Hormones and Defenses in Tomato Root Exudates

In this work, we use electrophysiological and metabolomic tools to determine the role of chitosan as plant defense elicitor in soil for preventing or manage root pests and diseases sustainably. Root exudates include a wide variety of molecules that plants and root microbiota use to communicate in the rhizosphere. Tomato plants were treated with chitosan. Root exudates from tomato plants were analyzed at 3, 10, 20, and 30 days after planting (dap). We found, using high performance liquid chromatography (HPLC) and excitation emission matrix (EEM) fluorescence, that chitosan induces plant hormones, lipid signaling and defense compounds in tomato root exudates, including phenolics. High doses of chitosan induce membrane depolarization and affect membrane integrity. 1H-NMR showed the dynamic of exudation, detecting the largest number of signals in 20 dap root exudates. Root exudates from plants irrigated with chitosan inhibit ca. twofold growth kinetics of the tomato root parasitic fungus Fusarium oxysporum f. sp. radicis-lycopersici. and reduced ca. 1.5-fold egg hatching of the root-knot nematode Meloidogyne javanica.