Differential accumulation of silymarin induced by exposure of Silybum marianum L. callus cultures to several spectres of monochromatic lights

FAAH Modulators from Natural Sources: A Collection of New Potential Drugs

The endocannabinoid system (ECS) plays a crucial role in maintaining homeostasis by regulating immune response, energy metabolism, cognitive functions, and neuronal activity. It consists of endocannabinoids (eCBs), cannabinoid receptors (CBRs), and enzymes involved in eCB biosynthesis and degradation. Increasing evidence highlights the involvement of the ECS under several pathological conditions, making it a promising therapeutic target. Recent research efforts have focused on modulating endogenous eCB levels, particularly through the inhibition of fatty acid amide hydrolase (FAAH), the main catabolic enzyme of the major eCB anandamide. Natural substances, including plant extracts and purified compounds, can inhibit FAAH and represent a promising area of pharmacological research. Natural FAAH inhibitors are particularly attractive due to their potentially lower toxicity compared to synthetic compounds, making them safer candidates for therapeutic applications. Phytocannabinoids, flavonoids, and flavolignans have been shown to efficiently inhibit FAAH. The structural diversity and bioactivity of these natural substances provide a valuable alternative to synthetic inhibitors, and may open new avenues for developing innovative pharmacological tools.

Optimizing Green Extraction Methods for Maximizing the Biological Potential of Dandelion, Milk Thistle, and Chamomile Seed Extracts

This study investigates the underutilized potential of agri-crops from the Asteraceae family by employing sustainable and green technologies (supercritical fluid, ultrasound, and Soxhlet extractions) to enhance the recovery of bioactive compounds. A total of 21 extracts from native and waste seeds of dandelion, milk thistle, and chamomile were systematically compared utilizing a combination of solvents (supercritical CO2 and absolute or aqueous ethanol). Supercritical CO2 extraction yielded up to 281 mg/g of oils from native seeds, while conventional techniques with ethanol recovered an additional 142 mg/g of extracts from waste seeds. Notably, waste seed extracts exhibited superior biological activity, including potent antioxidant properties (IC50 values as low as 0.3 mg/mL in the DPPH assay) and broad-spectrum antimicrobial activity against 32 microbial strains, including methicillin-resistant Staphylococcus aureus, Gram-negative bacteria, and yeast strains. Phenolic compounds were abundant, with up to 2126 mg GAE/g, alongside 25.9 mg QE/g flavonoids, and 805.5 mg/kg chlorophyll A. A selective anticancer activity of waste milk thistle extracts was observed, with a selectivity index of 1.9 to 2.7. The oils recovered from native seeds demonstrated lower bioactivity and are well-suited for applications in food. The potent bioactivity of the smaller quantities of waste seed extracts positions them as valuable candidates for pharmaceutical use.

Anti-Inflammatory, Antioxidant, and Genoprotective Effects of Callus Cultures Obtained from the Pulp of Malus pumila cv Miller (Annurca Campana Apple)

Apples are rich in phytochemicals useful for human health. However, environmental factors can greatly affect the accumulation of these compounds. To face this problem, the callus culture technique was used to obtain large quantities of phytochemicals. Specifically, two callus cultures were obtained from ripe Annurca apple pulp (Malus pumila cv Miller) and cultivated under different light conditions: darkness and an 18-h photoperiod. The hydro-alcoholic extracts from the calli underwent analysis using GC-MS, GC-FID, and HPLC-DAD-ESI-MSn to determine the qualitative and quantitative content of phenolic and triterpenic acids. The study revealed the predominant presence of triterpenic compounds in both calli. Furthermore, we investigated their radical scavenging and antioxidant activities through DPPH, ABTS, ORAC assays, and lipoxygenase inhibition activity. Genoprotection was evaluated via nicking assay, and the anti-inflammatory effect was investigated via Griess assay on LPS-injured murine macrophages. All the analyses performed were compared with peel and pulp hydroalcoholic extracts. The results showed that both calli primarily show anti-inflammatory activity and moderate antioxidant effect and can protect DNA against oxidative stimuli. This data encouraged further research aimed at utilizing callus as a bioreactor to produce secondary metabolites for use in preventive and therapeutic applications to combat acute or chronic age-associated diseases.

Influence of Abiotic and Biotic Elicitors on Organogenesis, Biomass Accumulation, and Production of Key Secondary Metabolites in Asteraceae Plants

The medicinal plants of the Asteraceae family are a valuable source of bioactive secondary metabolites, including polyphenols, phenolic acids, flavonoids, acetylenes, sesquiterpene lactones, triterpenes, etc. Under stressful conditions, the plants develop these secondary substances to carry out physiological tasks in plant cells. Secondary Asteraceae metabolites that are of the greatest interest to consumers are artemisinin (an anti-malarial drug from Artemisia annua L.-sweet wormwood), steviol glycosides (an intense sweetener from Stevia rebaudiana Bert.-stevia), caffeic acid derivatives (with a broad spectrum of biological activities synthesized from Echinacea purpurea (L.) Moench-echinacea and Cichorium intybus L.-chicory), helenalin and dihydrohelenalin (anti-inflammatory drug from Arnica montana L.-mountain arnica), parthenolide ("medieval aspirin" from Tanacetum parthenium (L.) Sch.Bip.-feverfew), and silymarin (liver-protective medicine from Silybum marianum (L.) Gaertn.-milk thistle). The necessity to enhance secondary metabolite synthesis has arisen due to the widespread use of these metabolites in numerous industrial sectors. Elicitation is an effective strategy to enhance the production of secondary metabolites in in vitro cultures. Suitable technological platforms for the production of phytochemicals are cell suspension, shoots, and hairy root cultures. Numerous reports describe an enhanced accumulation of desired metabolites after the application of various abiotic and biotic elicitors. Elicitors induce transcriptional changes in biosynthetic genes, leading to the metabolic reprogramming of secondary metabolism and clarifying the mechanism of the synthesis of bioactive compounds. This review summarizes biotechnological investigations concerning the biosynthesis of medicinally essential metabolites in plants of the Asteraceae family after various elicitor treatments.

Co-cultures from Plants and Cyanobacteria: A New Way for Production Systems in Agriculture and Bioprocess Engineering

Due to the global increase in the world population, it is not possible to ensure a sufficient food supply without additional nitrogen input into the soil. About 30-50% of agricultural yields are due to the use of chemical fertilizers in modern times. However, overfertilization threatens biodiversity, such as nitrogen-loving, fast-growing species overgrow others. The production of artificial fertilizers produces nitrogen oxides, which act as greenhouse gases. In addition, overfertilization of fields also releases ammonia, which damages surface waters through acidification and eutrophication. Diazotrophic cyanobacteria, which usually form a natural, stable biofilm, can fix nitrogen from the atmosphere and release it into the environment. Thus, they could provide an alternative to artificial fertilizers. In addition to this, biofilms stabilize soils and thus protect against soil erosion and desiccation. This chapter deals with the potential of cyanobacteria as the use of natural fertilizer is described. Possible partners such as plants and callus cells and the advantages of artificial co-cultivation will be discussed later. In addition, different cultivation systems for studying artificial co-cultures will be presented. Finally, the potential of artificial co-cultures in the agar industry will be discussed.

Trends in the Tissue Culture Techniques and the Synthesis of Bioactive Compounds in Eurycoma longifolia Jack-Current Status and Future Perspectives

Over the last two decades, there has been a concerted effort by researchers to mass propagate Eurycoma longifolia and improve the yield of its very important and sought-after anti-cancer and aphrodisiac bioactive compounds. To achieve this, various techniques have been used to mass propagate and improve the yield of these bioactive compounds in tissue cultures. These techniques include the optimization of media conditions and application of various types and combinations of plant growth regulators (PGRs). In addition, some elicitation techniques have been used to improve the synthesis of these bioactive compounds. However, in comparison with other herbal species with similar economic importance, many techniques have not been applied to E. longifolia. Adopting the most recent methodologies would ensure efficiency and sustainability in the in vitro production of bioactive compounds in E. longifolia. Therefore, in this review, we present an up-to-date record on the success stories in the tissue culture techniques and synthesis of bioactive compounds. In addition, we attempted to identify some of the missing links on the road to the effective and sustainable biotechnological utilization of this super important biological resource.

From Nature to Lab: A Review of Secondary Metabolite Biosynthetic Pathways, Environmental Influences, and In Vitro Approaches

Secondary metabolites are gaining an increasing importance in various industries, such as pharmaceuticals, dyes, and food, as is the need for reliable and efficient methods of procuring these compounds. To develop sustainable and cost-effective approaches, a comprehensive understanding of the biosynthetic pathways and the factors influencing secondary metabolite production is essential. These compounds are a unique type of natural product which recognizes the oxidative damage caused by stresses, thereby activating the defence mechanism in plants. Various methods have been developed to enhance the production of secondary metabolites in plants. The elicitor-induced in vitro culture technique is considered an efficient tool for studying and improving the production of secondary metabolites in plants. In the present review, we have documented various biosynthetic pathways and the role of secondary metabolites under diverse environmental stresses. Furthermore, a practical strategy for obtaining consistent and abundant secondary metabolite production via various elicitation agents used in culturing techniques is also mentioned. By elucidating the intricate interplay of regulatory factors, this review paves the way for future advancements in sustainable and efficient production methods for high-value secondary metabolites.

Integrated metabolome and transcriptome analyses provide insight into the effect of red and blue LEDs on the quality of sweet potato leaves

Red and blue light-emitting diodes (LEDs) affect the quality of sweet potato leaves and their nutritional profile. Vines cultivated under blue LEDs had higher soluble protein contents, total phenolic compounds, flavonoids, and total antioxidant activity. Conversely, chlorophyll, soluble sugar, protein, and vitamin C contents were higher in leaves grown under red LEDs. Red and blue light increased the accumulation of 77 and 18 metabolites, respectively. Alpha-linoleic and linolenic acid metabolism were the most significantly enriched pathways based on Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. A total of 615 genes were differentially expressed between sweet potato leaves exposed to red and blue LEDs. Among these, 510 differentially expressed genes were upregulated in leaves grown under blue light compared with those grown under red light, while the remaining 105 genes were expressed at higher levels in the latter than in the former. Among the KEGG enrichment pathways, blue light significantly induced anthocyanin and carotenoid biosynthesis structural genes. This study provides a scientific reference basis for using light to alter metabolites to improve the quality of edible sweet potato leaves.

Phenolic Acids and Amaryllidaceae Alkaloids Profiles in Leucojum aestivum L. In Vitro Plants Grown under Different Light Conditions

Light-emitting diodes (LEDs) have emerged as efficient light sources for promoting in vitro plant growth and primary and secondary metabolite biosynthesis. This study investigated the effects of blue, red, and white-red LED lights on plant biomass growth, photosynthetic pigments, soluble sugars, phenolic compounds, the production of Amaryllidaceae alkaloids, and the activities of antioxidant enzymes in Leucojum aestivum L. cultures. A white fluorescent light was used as a control. The plants that were grown under white-red and red light showed the highest fresh biomass increments. The blue light stimulated chlorophyll a, carotenoid, and flavonoid production. The white-red and blue lights were favourable for phenolic acid biosynthesis. Chlorogenic, p-hydroxybenzoic, caffeic, syringic, p-coumaric, ferulic, sinapic, and benzoic acids were identified in plant materials, with ferulic acid dominating. The blue light had a significant beneficial effect both on galanthamine (4.67 µg/g of dry weight (DW)) and lycorine (115 µg/g DW) biosynthesis. Red light treatment increased catalase and superoxide dismutase activities, and high catalase activity was also observed in plants treated with white-red and blue light. This is the first report to provide evidence of the effects of LED light on the biosynthesis of phenolic acid and Amaryllidaceae alkaloids in L. aestivum cultures, which is of pharmacological importance and can propose new strategies for their production.

Effect of Wide-Spectrum Monochromatic Lights on Growth, Phytochemistry, Nutraceuticals, and Antioxidant Potential of In Vitro Callus Cultures of Moringa oleifera

Moringa oleifera, also called miracle tree, is a pharmaceutically important plant with a multitude of nutritional, medicinal, and therapeutic attributes. In the current study, an in-vitro-based elicitation approach was used to enhance the commercially viable bioactive compounds in an in vitro callus culture of M. oleifera. The callus culture was established and exposed to different monochromatic lights to assess the potentially interactive effects on biomass productions, biosynthesis of pharmaceutically valuable secondary metabolites, and antioxidant activity. Optimum biomass production (16.7 g/L dry weight), total phenolic contents (TPC: 18.03 mg/g), and flavonoid contents (TFC: 15.02 mg/g) were recorded in callus cultures placed under continuous white light (24 h), and of other light treatments. The highest antioxidant activity, i.e., ABTS (550.69 TEAC µM) and FRAP (365.37 TEAC µM), were also noted under white light (24 h). The analysis of phytochemicals confirmed the significant impact of white light exposures on the enhanced biosynthesis of plant secondary metabolites. The enhanced levels of secondary metabolites, i.e., kaempferol (1016.04 µg/g DW), neochlorogenic acid (998.38 µg/g DW), quercetin (959.92 µg/g DW), and minor compounds including luteolin, apigenin, and p-coumaric acid were observed as being highest in continuous white light (24 h with respect to the control (photoperiod). Similarly, blue light enhanced the chlorogenic acid accumulation. This study shows that differential spectral lights demonstrate a good approach for the enhancement of nutraceuticals along with novel pharmacologically important metabolites and antioxidants in the in vitro callus culture of M. oleifera.

Light Quality-Mediated Influence of Morphogenesis in Micropropagated Horticultural Crops: A Comprehensive Overview

In plants, light quality plays significant roles in photomorphogenesis and photosynthesis. Efficient in vitro plant propagation techniques involve tailoring of various environmental cues and culture media according to the plant species. Plant tissue culture consists of several applications in scientific research, agriculture, biotechnology, and commercial industrial purposes. Utilization of light to enhance the quality of the in vitro raised plants have been evidenced by numerous researchers in plant tissue culture. The advent of light-emitting diode- (LED-) based artificial lighting systems in plant tissue culture for micropropagation has enhanced callus induction, shoot and root organogenesis, and acclimatization of in vitro propagated plants. Plants tend to perceive the light spectra present in the photosynthetically active region (PAR) ranging from 400 to 700 nm; this includes blue and red light wavelengths. Although the influence of spectral quality is being investigated in diverse plant species, particularly, its importance in in vitro propagated horticultural crops is gaining notable interest among researchers. In recent days, the application of LEDs provides better amenability according to the plant species of interest for efficient plant regeneration. Considering the growing necessity and emerging applications of LED supplemental lights for propagation of plants in in vitro, the present review summarizes the outcomes of various research studies dealing with LEDs in plant tissue culture. Moreover, the present endeavor has provided a comprehensive overview on the effects of LEDs in the morphogenesis of plants cultured in vitro.

Comparative Analysis of Various Plant-Growth-Regulator Treatments on Biomass Accumulation, Bioactive Phytochemical Production, and Biological Activity of Solanum virginianum L. Callus Culture Extracts

Solanum virginianum L. (Solanum xanthocarpum) is an important therapeutic plant due to the presence of medicinally useful plant-derived compounds. S. virginianum has been shown to have anticancer, antioxidant, antibacterial, antiaging, and anti-inflammatory properties. This plant is becoming endangered due to overexploitation and the loss of its native habitat. The purpose of this research is to develop an ideal technique for the maximum biomass and phytochemical accumulation in S. virginianum leaf-induced in vitro cultures, as well as to evaluate their potential antiaging, anti-inflammatory, and antioxidant abilities. Leaf explants were grown on media (Murashige and Skoog (MS)) that were supplemented with various concentrations and combinations of plant hormones (TDZ, BAP, NAA, and TDZ + NAA) for this purpose. When compared with the other hormones, TDZ demonstrated the best response for callus induction, biomass accumulation, phytochemical synthesis, and biological activities. However, with 5 mg/L of TDZ, the optimal biomass production (FW: 251.48 g/L and DW: 13.59 g/L) was estimated. The highest total phenolic level (10.22 ± 0.44 mg/g DW) was found in 5 mg/L of TDZ, whereas the highest flavonoid contents (1.65 ± 0.11 mg/g DW) were found in 10 mg/L of TDZ. The results of the HPLC revealed that the highest production of coumarins (scopoletin: 4.34 ± 0.20 mg/g DW and esculetin: 0.87 ± 0.040 mg/g DW) was determined for 10 mg/L of TDZ, whereas the highest accumulations of caffeic acid (0.56 ± 0.021 mg/g DW) and methyl caffeate (18.62 ± 0.60 mg/g DW) were shown by 5 mg/L of TDZ. The determination of these phytochemicals (phenolics and coumarins) estimates that the results of our study on biological assays, such as antioxidant, anti-inflammatory, and antiaging assays, are useful for future cosmetic applications.

Elicitation of Submerged Adventitious Root Cultures of Stevia rebaudiana with Cuscuta reflexa for Production of Biomass and Secondary Metabolites

Stevia rebaudiana is an important medicinal plant that belongs to the Asteraceae family. The leaves of Stevia rebaudiana are a rich source of many health-promoting agents such as polyphenols, flavonoids, and steviol glycoside, which play a key role in controlling obesity and diabetes. New strategies such as the elicitation of culture media are needed to enhance the productivity of active components. Herein, the Cuscuta reflexa extracts were exploited as elicitors to enhance the productivity of active components. Cuscuta reflexa is one of the parasitic plants that has the ability to elongate very fast and cover the host plant. Consequently, it may be possible that the addition of Cuscuta reflexa extracts to adventitious root cultures (ADR) of Stevia rebaudiana may elongate the root more than control cultures to produce higher quantities of the desired secondary metabolites. Therefore, the main objective of the current study was to investigate the effect of Cuscuta reflexa extract as a biotic elicitor on the biomass accumulation and production of antioxidant secondary metabolite in submerged adventitious root cultures of Stevia rebaudiana. Ten different concentrations of Cuscuta reflexa were added to liquid media containing 0.5 mg/L naphthalene acetic acid (NAA). The growth kinetics of adventitious roots was investigated for a period of 49 days with an interval of 7 days. The maximum biomass accumulation (7.83 g/3 flasks) was observed on medium containing 10 mg/L extract of Cuscuta reflexa on day 49. As the concentration of extract increases in the culture media, the biomass gradually decreases after 49 days of inoculation. In this study, the higher total phenolics content (0.31 mg GAE/g-DW), total flavonoids content (0.22 mg QE/g-DW), and antioxidant activity (85.54%) were observed in 100 mg/L treated cultures. The higher concentration (100 mg/L) of Cuscuta reflexa extract considerably increased the total phenolics content (TPC), total phenolics production (TPP), total flavonoids content (TFC), total flavonoids production (TFP), total polyphenolics content (TPPC), and total polyphenolics production (TPPP). It was concluded that the extract of Cuscuta reflexa moderately improved biomass accumulation but enhanced the synthesis of phenolics, flavonoids, and antioxidant activities. Here, biomass’s independent production of secondary metabolites was observed with the addition of extract. The present study will be helpful to scale up adventitious roots culture into a bioreactor for the production of secondary metabolites rather than biomass accumulation in medicinally important Stevia rebaudiana.

Green and chemically synthesized zinc oxide nanoparticles: effects on in-vitro seedlings and callus cultures of Silybum marianum and evaluation of their antimicrobial and anticancer potential

Zinc oxide nanoparticles (ZnO-NPs) have been produced by physical and chemical methods. Here, the comparative evaluation of both chemically-synthesised ZnO-NPs (C-ZNPs) and in-vitro cultured S. marianum mediated green-synthesised ZnO-NPs (G-ZNPs) were investigated on seed germination frequency, root and shoot growth, callus induction and biochemical profile of medicinally important plant Silybum marianum. Of all the treatments, callus-mediated ZnO-NPs gave optimum results for seed germination (65%), plantlet's root length (4.3 cm), shoot length (5.3 cm) and fresh and dry weights (220.4 g L-1 and 21.23 g L-1, respectively). Similarly, the accumulation of phenolic (12.3 µg/mg DW) and flavonoid (2.8 µg/mg DW) contents were also enhanced in callus cultures treated with G-ZNPs. We also observed maximum antioxidant activity (99%) in callus cultures treated with G-ZNPs, however, in case of plantlets, these activities were found highest for in-vitro whole plant-mediated ZnO-NPs. Moreover, G-ZNPs also enhanced total protein content (265.32 BSAE/20g FW) in callus cultures. G-ZNPs were further assessed for their effects on several multidrug resistant bacterial strains and human liver carcinoma (HepG2) cells and our findings revealed that callus extracts treated with G-ZNPs show ameliorated antibacterial (highest zone of inhibition (19 mm) against Klebsiella pneumonia) and anticancer (highest cytotoxicity of 64%) activities.

Scarlet Flax Linum grandiflorum (L.) In Vitro Cultures as a New Source of Antioxidant and Anti-Inflammatory Lignans

In vitro cultures of scarlet flax (Linum grandiflorum L.), an important ornamental flax, have been established as a new possible valuable resource of lignans and neolignans for antioxidant and anti-inflammatory applications. The callogenic potential at different concentrations of α-naphthalene acetic acid (NAA) and thidiazuron (TDZ), alone or in combinations, was evaluated using both L. grandiflorum hypocotyl and cotyledon explants. A higher callus induction frequency was observed on NAA than TDZ, especially for hypocotyl explants, with a maximum frequency (i.e., 95.2%) on 1.0 mg/L of NAA. The presence of NAA (1.0 mg/L) in conjunction with TDZ tended to increase the frequency of callogenesis relative to TDZ alone, but never reached the values observed with NAA alone, thereby indicating the lack of synergy between these two plant growth regulators (PGRs). Similarly, in terms of biomass, NAA was more effective than TDZ, with a maximum accumulation of biomass registered for medium supplemented with 1.0 mg/L of NAA using hypocotyls as initial explants (DW: 13.1 g). However, for biomass, a synergy between the two PGRs was observed, particularly for cotyledon-derived explants and for the lowest concentrations of TDZ. The influence of these two PGRs on callogenesis and biomass is discussed. The HPLC analysis confirmed the presence of lignans (secoisolariciresinol (SECO) and lariciresinol (LARI) and neolignan (dehydrodiconiferyl alcohol [DCA]) naturally accumulated in their glycoside forms. Furthermore, the antioxidant activities performed for both hypocotyl- and cotyledon-derived cultures were also found maximal (DPPH: 89.5%, FRAP 866: µM TEAC, ABTS: 456 µM TEAC) in hypocotyl-derived callus cultures as compared with callus obtained from cotyledon explants. Moreover, the anti-inflammatory activities revealed high inhibition (COX-1: 47.4% and COX-2: 51.1%) for extract of hypocotyl-derived callus cultures at 2.5 mg/L TDZ. The anti-inflammatory action against COX-1 and COX-2 was supported by the IC₅₀ values. This report provides a viable approach for enhanced biomass accumulation and efficient production of (neo)lignans in L. grandiflorum callus cultures.

Comparative Effects of Different Light Sources on the Production of Key Secondary Metabolites in Plants In Vitro Cultures

Plant secondary metabolites are known to have a variety of biological activities beneficial to human health. They are becoming more popular as a result of their unique features and account for a major portion of the pharmacological industry. However, obtaining secondary metabolites directly from wild plants has substantial drawbacks, such as taking a long time, posing a risk of species extinction owing to over-exploitation, and producing a limited quantity. Thus, there is a paradigm shift towards the employment of plant tissue culture techniques for the production of key secondary metabolites in vitro. Elicitation appears to be a viable method for increasing phytochemical content and improving the quality of medicinal plants and fruits and vegetables. In vitro culture elicitation activates the plant's defense response and increases the synthesis of secondary metabolites in larger proportions, which are helpful for therapeutic purposes. In this respect, light has emerged as a unique and efficient elicitor for enhancing the in vitro production of pharmacologically important secondary metabolites. Various types of light (UV, fluorescent, and LEDs) have been found as elicitors of secondary metabolites, which are described in this review.

Gene Expression Analysis and Metabolite Profiling of Silymarin Biosynthesis during Milk Thistle (Silybum marianum (L.) Gaertn.) Fruit Ripening

Mature fruits (i.e., achenes) of milk thistle (Silybum marianum (L.) Gaertn., Asteraceae) accumulate high amounts of silymarin (SILM), a complex mixture of bioactive flavonolignans deriving from taxifolin. Their biological activities in relation with human health promotion and disease prevention are well described. However, the conditions of their biosynthesis in planta are still obscure. To fill this gap, fruit development stages were first precisely defined to study the accumulation kinetics of SILM constituents during fruit ripening. The accumulation profiles of the SILM components during fruit maturation were determined using the LC-MS analysis of these defined developmental phases. The kinetics of phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS) and peroxidase (POX) activities suggest in situ biosynthesis of SILM from l-Phenylalanine during fruit maturation rather than a transport of precursors to the achene. In particular, in contrast to laccase activity, POX activity was associated with the accumulation of silymarin, thus indicating a possible preferential involvement of peroxidase(s) in the oxidative coupling step leading to flavonolignans. Reference genes have been identified, selected and validated to allow accurate gene expression profiling of candidate biosynthetic genes (PAL, CAD, CHS, F3H, F3'H and POX) related to SILM accumulation. Gene expression profiles were correlated with SILM accumulation kinetic and preferential location in pericarp during S. marianum fruit maturation, reaching maximum biosynthesis when desiccation occurs, thus reinforcing the hypothesis of an in situ biosynthesis. This observation led us to consider the involvement of abscisic acid (ABA), a key phytohormone in the control of fruit ripening process. ABA accumulation timing and location during milk thistle fruit ripening appeared in line with a potential regulation of the SLIM accumulation. A possible transcriptional regulation of SILM biosynthesis by ABA was supported by the presence of ABA-responsive cis-acting elements in the promoter regions of the SILM biosynthetic genes studied. These results pave the way for a better understanding of the biosynthetic regulation of SILM during the maturation of S. marianum fruit and offer important insights to better control the production of these medicinally important compounds.

Lights triggered differential accumulation of antioxidant and antidiabetic secondary metabolites in callus culture of Eclipta alba L

Eclipta alba L., also known as false daisy, is well known and commercially attractive plant with excellent hepatotoxic and antidiabetic activities. Light is considered a key modulator in plant morphogenesis and survival by regulating important physiological cascades. Current study was carried out to investigate growth and developmental aspects of E. alba under differential effect of multispectral lights. In vitro derived callus culture of E. alba was exposed to multispectral monochromatic lights under controlled aseptic conditions. Maximum dry weight was recorded in culture grown under red light (11.2 g/L) whereas negative effect was observed under exposure of yellow light on callus growth (4.87 g/L). Furthermore, red light significantly enhanced phenolics and flavonoids content (TPC: 57.8 mg/g, TFC: 11.1 mg/g) in callus cultures compared to rest of lights. HPLC analysis further confirmed highest accumulation of four major compounds i.e. coumarin (1.26 mg/g), eclalbatin (5.00 mg/g), wedelolactone (32.54 mg/g) and demethylwedelolactone (23.67 mg/g) and two minor compounds (β-amyrin: 0.38 mg/g, luteolin: 0.39 mg/g) in red light treated culture whereas stigmasterol was found optimum (0.22 mg/g) under blue light. In vitro based biological activities including antioxidant, antidiabetic and lipase inhibitory assays showed optimum values in cultures exposed to red light, suggesting crucial role of these phytochemicals in the enhancement of the therapeutic potential of E. alba. These results clearly revealed that the use of multispectral lights in in vitro cultures could be an effective strategy for enhanced production of phytochemicals.

Interactive Effects of Wide-Spectrum Monochromatic Lights on Phytochemical Production, Antioxidant and Biological Activities of Solanum xanthocarpum Callus Cultures

Solanum xanthocarpum is considered an important traditional medicinal herb because of its unique antioxidant, and anti-diabetic, anti-aging, and anti-inflammatory potential. Because of the over exploitation linked to its medicinal properties as well as destruction of its natural habitat, S. xanthocarpum is now becoming endangered and its supply is limited. Plant in vitro culture and elicitation are attractive alternative strategies to produce biomass and stimulate biosynthesis of medicinally important phytochemicals. Here, we investigated the potential influence of seven different monochromatic light treatments on biomass and secondary metabolites accumulation in callus culture of S. xanthocarpum as well as associated biological activities of the corresponding extracts. Among different light treatments, highest biomass accumulation was observed in white light-treated callus culture. Optimum accumulation of total flavonoid contents (TFC) and total phenolic contents (TPC) were observed in callus culture kept under continuous white and blue light respectively than control. Quantification of phytochemicals through HPLC revealed that optimum production of caffeic acid (0.57 ± 0.06 mg/g DW), methyl-caffeate (17.19 mg/g ± 1.79 DW), scopoletin (2.28 ± 0.13 mg/g DW), and esculetin (0.68 ± 0.07 mg/g DW) was observed under blue light callus cultures. Compared to the classic photoperiod condition, caffeic acid, methyl-caffeate, scopoletin, and esculetin were accumulated 1.7, 2.5, 1.1, and 1.09-folds higher, respectively. Moreover, high in vitro cell free antioxidant, anti-diabetic, anti-aging, and anti-inflammatory activities were closely associated with the production of these secondary metabolites. These results clearly showed the interest to apply multispectral light as elicitor of in vitro callus cultures S. xanthocarpum to promote the production of important phytochemicals, and allow us to propose this system as an alternative for the collection of this endangered species from the wild.

Spectral quality as an elicitor of bioactive compound production in Solanum aculeatissimum JACQ cell suspension

Solanum aculeatissimum Jacq. is a common plant in much of Brazil. Despite containing metabolites with a wide range of pharmacological applications, there are few tissue culture reports for this plant. The possibility of large-scale in vitro production of this material has significant biotechnological potential. Therefore, the objective of this study was to investigate the effect of light conditions on the growth of cells in suspension, observing the production and yield of biomass and bioactive compounds and the enzymatic behavior. Calli obtained from leaf segments were cultured in solid medium supplemented with 1 mg L^-1 of 2,4-D, 2.5 mg L^-1 kinetin, pH 5.7, in the dark. After 110 days of subculture, the calli were transferred to liquid medium. Cells were kept in the dark under agitation at 110 rpm and 25 °C and subcultured every 30 days. After 90 days of culture, 20 mL aliquots of cell suspension were added to flasks containing approximately 20 mL of medium (1:1) and cultured at different wavelengths (white, green, blue, red, and blue/red) under a photoperiod of 16 h with irradiance of 50 μmol m^-2 s^-1) and in the absence of light. The experiment was performed in a 6 × 6 factorial design (light condition × culture time). The cell cultures showed viability throughout the entire cycle, and chlorogenic and ferulic acids, orientin, quercitrin and, in higher amounts, quercetin, were detected in the first 7 days of culture. There was an increase in superoxide dismutase and catalase and a decrease in ascorbate peroxidase after exposure to different light conditions; for phenylalanine ammonia lyase, no differences were observed. The different light conditions were not sufficient to trigger responses in the concentrations of bioactive compounds, despite the detection of increased levels of the enzymes involved in cellular homeostasis.

UPLC-HRMS Analysis Revealed the Differential Accumulation of Antioxidant and Anti-Aging Lignans and Neolignans in In Vitro Cultures of Linum usitatissimum L

Over the last few decades, methods relating to plant tissue culture have become prevalent within the cosmetic industry. Forecasts predict the cosmetic industry to grow to an annual turnover of around a few hundred billion US dollars. Here we focused on Linum usitatissimum L., a plant that is well-known for its potent cosmetic properties. Following the a) establishment of cell cultures from three distinct initial explant origins (root, hypocotyl, and cotyledon) and b) selection of optimal hormonal concentrations, two in vitro systems (callus vs cell suspensions) were subjected to different light conditions. Phytochemical analysis by UPLC-HRMS not only confirmed high (neo)lignan accumulation capacity of this species with high concentrations of seven newly described (neo)lignans. Evaluation over 30 days revealed strong variations between the two different in vitro systems cultivated under light or dark, in terms of their growth kinetics and phytochemical composition. Additionally, antioxidant (i.e. four different in vitro assays based on hydrogen-atom transfer or electron transfer mechanism) and anti-aging (i.e. four in vitro inhibition potential of the skin remodeling enzymes: elastase, hyaluronidase, collagenase and tyrosinase) properties were evaluated for the two different in vitro systems cultivated under light or dark. A prominent hydrogen-atom transfer antioxidant mechanism was illustrated by the DPPH and ABTS assays. Potent tyrosinase and elastase inhibitory activities were also observed, which was strongly influenced by the in vitro system and light conditions. Statistical treatments of the data showed relationship of some (neo)lignans with these biological activities. These results confirmed the accumulation of flax (neo)lignans in different in vitro systems that were subjected to distinct light conditions. Furthermore, we showed the importance of optimizing these parameters for specific applications within the cosmetic industry.

Monochromatic lights-induced trends in antioxidant and antidiabetic polyphenol accumulation in in vitro callus cultures of Lepidium sativum L

Lepidium sativum L. is an important edible, herbaceous plant with huge medicinal value as cardio-protective, hepatoprotective and antitumor agent. This study was designed and performed to investigate biosynthesis of plant's active ingredients in callus cultures of L. sativum in response to the exposure of multi spectral lights. Optimum biomass accumulation (15.36 g/L DW), total phenolic and flavonoid contents (TPC; 47.43 mg/g; TFC; 9.41 mg/g) were recorded in calli placed under white light (24 h) compared to rest of the treatments. Antioxidant enzymatic activities i.e. superoxide dismutase and peroxidase were found optimum in cultures exposed to green light (SOD; 0.054 nM/min/mg FW, POD; 0.501 nM/min/mg FW). Phytochemical analysis further confirmed the potential influence of white light exposure on enhanced production of plant's metabolites. Significant enhancement level of major metabolic compounds such as chlorogenic acid (7.20 mg/g DW), quercetin (22.08 mg/g DW), kaempferol (7.77 mg/g DW) and minor compounds including ferulic acid, sinapic acid, protocatechuic acid, vanillic acid and caffeic acid were recorded in white light compared to control (photoperiod), whereas blue light increased the p-coumaric acid accumulation. Moreover, callus cultures of this plant under white light (24 h) showed highest in vitro based anti-diabetic and antioxidant activities compared to other conditions. Finding of our current study revealed that multi spectral lights are proved to be an effective strategy for enhancing metabolic quantity of antioxidant and anti-diabetic bioactive compounds in callus cultures of L. sativum L.

Interactive Effects of Light and Melatonin on Biosynthesis of Silymarin and Anti-Inflammatory Potential in Callus Cultures of Silybum marianum (L.) Gaertn

Silybum marianum (L.) Gaertn. is a well-known medicinal herb, primarily used in liver protection. Light strongly affects several physiological processes along with secondary metabolites biosynthesis in plants. Herein, S. marianum was exploited for in vitro potential under different light regimes in the presence of melatonin. The optimal callogenic response occurred in the combination of 1.0 mg/L α-naphthalene acetic acid and 0.5 mg/L 6-benzylaminopurine under photoperiod. Continuous light associated with melatonin treatment increased total flavonoid content (TFC), total phenolic content (TPC) and antioxidant potential, followed by photoperiod and dark treatments. The increased level of melatonin has a synergistic effect on biomass accumulation under continuous light and photoperiod, while an adverse effect was observed under dark conditions. More detailed phytochemical analysis showed maximum total silymarin content (11.92 mg/g dry weight (DW)) when placed under continuous light + 1.0 mg/L melatonin. Individually, the level of silybins (A and B), silydianin, isolsilychristin and silychristin was found highest under continuous light. Anti-inflammatory activities were also studied and highest percent inhibition was recorded against 15-lipoxygenase (15-LOX) for cultures cultivated under continuous light (42.33%). The current study helps us to better understand the influence of melatonin and different light regimes on silymarin production as well as antioxidant and anti-inflammatory activities in S. marianum callus extracts.

Salicylic acid-enhanced biosynthesis of pharmacologically important lignans and neo lignans in cell suspension culture of Linum ussitatsimum L

Linum usitatsimum L. (flax) is a perennial herb with magnitude of medicinal and commercial applications. In the present study, we investigated the effects of salicylic acid (SA) on biosynthesis of lignans (secoisolariciresinol diglucoside (SDG) and lariciresinol diglucoside (LDG)) and neolignans (dehydrodiconiferyl alcohol glucoside (DCG) and guaiacylglycerol-β-coniferyl alcohol ether glucoside (GGCG)) in cell cultures of flax. Moderate concentration of SA (50 μM) enhanced biomass accumulation (10.98 g/L dry weight (DW)), total phenolic content (37.81 mg/g DW), and antioxidant potential (87.23%) to two-fold than their respective controls after 72 h of exposure. However, higher levels of total flavonoid content (5.32 mg/g DW) were noted after 48 h of exposure to 50 μM of SA. HPLC analyses revealed that 50 μM SA, significantly enhanced biosynthesis of SDG (7.95 mg/g DW), LDG (7.52 mg/g DW), DCG (54.90 mg/g DW), and GGCG (16.78 mg/g DW), which was almost 2.7, 1.8, 3.88, and 3.98 fold higher than their respective controls after 72 h of exposure time, respectively. These results indicated that moderate concentrations of SA had significant effects on biosynthesis and productivity of lignans and neolignans in cell culture of L. usitatissimum.

Isodon rugosus (Wall. ex Benth.) Codd In Vitro Cultures: Establishment, Phytochemical Characterization and In Vitro Antioxidant and Anti-Aging Activities

Isodon rugosus (Wall. ex Benth.) Codd accumulates large amounts of phenolics and pentacyclic triterpenes. The present study deals with the in vitro callus induction from stem and leaf explants of I. rugosus under various plant growth regulators (PGRs) for the production of antioxidant and anti-ageing compounds. Among all the tested PGRs, thidiazuron (TDZ) used alone or in conjunction with α-napthalene acetic acid (NAA) induced highest callogenesis in stem-derived explants, as compared to leaf-derived explants. Stem-derived callus culture displayed maximum total phenolic content and antioxidant activity under optimum hormonal combination (3.0 mg/L TDZ + 1.0 mg/L NAA). HPLC analysis revealed the presence of plectranthoic acid (373.92 µg/g DW), oleanolic acid (287.58 µg/g DW), betulinic acid (90.51 µg/g DW), caffeic acid (91.71 µg/g DW), and rosmarinic acid (1732.61 µg/g DW). Complete antioxidant and anti-aging potential of extracts with very contrasting phytochemical profiles were investigated. Correlation analyses revealed rosmarinic acid as the main contributor for antioxidant activity and anti-aging hyaluronidase, advance glycation end-products inhibitions and SIRT1 activation, whereas, pentacyclic triterpenoids were correlated with elastase, collagenase, and tyrosinase inhibitions. Altogether, these results clearly evidenced the great valorization potential of I. rugosus calli for the production of antioxidant and anti-aging bioactive extracts for cosmetic applications.

Synergistic effects of melatonin and distinct spectral lights for enhanced production of anti-cancerous compounds in callus cultures of Fagonia indica

Fagonia indica is one of the commercially vital medicinal plant species. It is well-known for biosynthesis of anticancer phenolics and flavonoids metabolites. The plant has been exploited for in vitro studies and production of vital phytochemicals, however, the synergistic effects of melatonin and lights remains to be investigated. In current study, we have evaluated the synergistic effects of melatonin and different light emitting diodes (LEDs) in callus cultures of F. indica. Both, light and melatonin play vital role in physiological and biochemical processes of plant cell. The highest Fresh weight (FW: 320 g/L) and Dry weight (DW: 20 g/L) was recorded in cultures under white LEDs. Optimum total phenolics content (11.3 μg GAE/mg), total flavonoids content (4.02 μg QAE/mg) and Free radical scavenging activity (97%) was found in cultures grown under white LED and melatonin. Furthermore, cultures maintained under white light were also found with highest levels of phenolic and flavonoids production (total phenolic production; 226.9 μg GAE/mg, Total flavonoid production; 81 μg QAE/mg) than other LED-grown cultures. However, the antioxidant enzymes; Superoxide dismutase (SOD: 0.53 nM/min/mg FW) and Peroxidase (POD:1.18 nM/min/mg FW) were found optimum in cultures grown under blue LED. The HPLC data showed that enhanced total production of metabolites was recorded in cultures under white LED (6.765 μg/mg DW) than other lights and control. The findings of this study comprehend the role of melatonin and influence of light quality on biomass accumulation and production of phytochemicals in callus cultures of F. indica.

Mechanistic evaluation of phytochemicals in breast cancer remedy: current understanding and future perspectives

Breast cancer is one of the most commonly diagnosed cancers around the globe and accounts for a large proportion of fatalities in women. Despite the advancement in therapeutic and diagnostic procedures, breast cancer still represents a major challenge. Current anti-breast cancer approaches include surgical removal, radiotherapy, hormonal therapy and the use of various chemotherapeutic drugs. However, drug resistance, associated serious adverse effects, metastasis and recurrence complications still need to be resolved which demand safe and alternative strategies. In this scenario, phytochemicals have recently gained huge attention due to their safety profile and cost-effectiveness. These phytochemicals modulate various genes, gene products and signalling pathways, thereby inhibiting breast cancer cell proliferation, invasion, angiogenesis and metastasis and inducing apoptosis. Moreover, they also target breast cancer stem cells and overcome drug resistance problems in breast carcinomas. Phytochemicals as adjuvants with chemotherapeutic drugs have greatly enhanced their therapeutic efficacy. This review focuses on the recently recognized molecular mechanisms underlying breast cancer chemoprevention with the use of phytochemicals such as curcumin, resveratrol, silibinin, genistein, epigallocatechin gallate, secoisolariciresinol, thymoquinone, kaempferol, quercetin, parthenolide, sulforaphane, ginsenosides, naringenin, isoliquiritigenin, luteolin, benzyl isothiocyanate, α-mangostin, 3,3'-diindolylmethane, pterostilbene, vinca alkaloids and apigenin.