Metabolites In Medicinal Plants Research Articles

Evaluation of Infected and Non-infected Wounds Healing Activity of Eriosema robustum Hydroethanolic Leaves Extract Ointments in Streptozotocin Induced Diabetic Rats

Untreated diabetic wounds provide an optimal environment for bacterial growth, which, over time, can develop resistance to common antibiotics and ultimately result in amputation. Therefore, it is necessary to search for new sources of antimicrobial molecules with wound healing activity owing to the presence of different secondary metabolites in medicinal plants. Aims: This study was to evaluate the in vivo antibacterial and diabetic wound healing capabilities of 70° hydroethanolic extract of Eriosema robustum leaves on non-infected and infected diabetic wound. Methodology: To do this, obese albino Wistar male rats (200–280 g) were divided into eleven groups and were made diabetic by intraperitoneal injection with a low dose of streptozotocin at 45 mg/kg of body weight. An excision wound with a surface area of 314 mm2 was created on the dorsal area of each animal, except in the uninjured diabetic group (UDG). The 70° hydroethanolic extract was used to prepare 1%, 5%, and 10% ointments, with L-Mesitran serving as the reference ointment. Healing potential was assessed by measuring wound contraction rates and determining serum and tissue hydroxyproline, serum lactate deydrogenase (LDH) and total protein levels (TP). The antibacterial power evaluated in vivo of Eriosema robustum leaves was also assessed by culturing the skin after healing. Results: The results demonstrated a significantly faster healing rate in the non-infected groups (5%,10% and L-Mesitran) compared to the infected groups. The levels of tissue hydroxyproline and total proteins were significantly (p < 0.05) elevated in all treated groups compared to infected and negative controls, unlike serum hydroxyproline levels. LDH levels were significantly (p < 0.05) elevated in both negative control group compared to the treated groups. The culture of different skin samples on previously injured areas on the 20th day of treatment showed no growth of S. aureus on completely healed areas and a low rate in the groups treated during the healing process. Conclusion: 70° Hydroethanolic leaves extract of Eriosema robustum possess in vivoantibacterial activities and diabetic wound healing potential.

Research progress in molecular pharmacognosy of Andrographis paniculata

Molecular pharmacognosy as an emerging interdisciplinary subject based on molecular biology and Chinese materia medica aims to study the synthesis and molecular regulation of secondary metabolites in medicinal plants. Andrographis Herba, the dried aboveground part of Andrographis paniculata, has liver-protecting, bile secretion-promoting, heat-clearing, toxin-removing, antimicrobial, and anti-inflammatory effects. The quality instability caused by plant varieties, environment, and technology in the production of A. paniculata is a limiting factor for the sustainable development of this industry. Based on the research methods of molecular pharmacognosy and omics, the regulation of secondary metabolites of A. paniculata has become the key solution to the quality problems of A. paniculata. This paper summarized the recent research achievements in the molecular pharmacognosy of A. paniculata, including molecular identification of the resources, genetic diversity, multi-omics, biosynthesis of active compounds, and germplasm resource innovation, and prospected the future development trend in this field. In-depth research of molecular pharmacognosy of A. paniculata will provide more scientific and effective technical support for the development of its medicinal value, give new insights into the cultivation of new A. paniculata varieties, and promote the high-quality sustainable development of this industry.

A generalist regulator: MYB transcription factors regulate the biosynthesis of active compounds in medicinal plants.

Medicinal plants are rich in a variety of secondary metabolites with therapeutic value. However, the yields of these metabolites are generally very low, making their extraction both time-consuming and labour-intensive. Transcription factor-targeted secondary metabolic engineering can efficiently regulate the biosynthesis and accumulation of secondary metabolites in medicinal plants. v-Myb avian myeloblastosis viral oncogene homolog (MYB) transcription factors are involved in regulating various morphological and developmental processes, responses to stress, and the biosynthesis of secondary metabolites in plants. This review discusses the biological functions and transcription regulation mechanisms of MYB transcription factors and summarizes research progress concerning MYB transcription factors involved in the biosynthesis of representative active components. In the transcriptional regulatory network, MYB transcription factors regulate multiple synthase genes to mediate the biosynthesis of active compounds. This work will serve as a reference for an in-depth analysis of the MYB transcription factor family in medicinal plants.

13C6-Glucose Labeling Associated with LC-MS: Identification of Plant Primary Organs in Secondary Metabolite Synthesis.

This paper presents a novel and efficient method for certifying primary organs involved in secondary metabolite synthesis. As the most important secondary metabolite in Parispolyphylla var. yunnanensis (Franch.) Hand. -Mzt. (PPY), Paris saponin (PS) has a variety of pharmacological activities and PPY is in increasing demand. This study established leaf, rhizome, and stem-vascular-bundle 13C6-Glucose feeding and non-feeding four treatments to precisely certify the primary organs involved in Paris saponins VII (PS VII) synthesis. By combining liquid chromatography-mass spectrometry (LC-MS), the 13C/12C ratios of leaf, rhizome, stem, and root in different treatments were quickly and accurately calculated, and four types of PS isotopic ion peak(M-) ratios were found: (M+1) -/M-, (M+2) -/M-, (M+3) -/M- and (M+4) -/M-. The results showed that the ratio of 13C/12C in the rhizomes of the stem-vascular-bundle and rhizome feeding treatments was significantly higher than that in the non-feeding treatment. Compared to the non-feeding treatment, the ratio of PS VII molecules (M+2) -/M- in the leaves increased significantly under leaf and stem-vascular-bundle feeding treatments. Simultaneously, compared to the non-feeding treatment, the ratio of PS VII molecules (M+2) -/M- in the leaves under rhizome treatment showed no significant difference. Furthermore, the ratio of PS VII molecules (M+2) -/M- in the stem, root, and rhizome showed no differences among the four treatments. Compared to the non-feeding treatment, the ratio of the Paris saponin II (PS II) molecule (M+2) -/M- in leaves under leaf feeding treatment showed no significant difference, and the (M+3) -/M- ratio of PS II molecules in leaves under leaf feeding treatment were lower. The data confirmed that the primary organ for the synthesizing of PS VII is the leaves. It lays the foundation for future identification of the primary organs and pathways involved in the synthesis of secondary metabolites in medicinal plants.

Beneficial endophytic fungi improve the yield and quality of Salvia miltiorrhiza by performing different ecological functions.

Endophytic fungi can enhance the growth and synthesis of secondary metabolites in medicinal plants. Salvia miltiorrhiza Bunge is frequently employed for treating cardiovascular and cerebrovascular ailments, with the primary bioactive components being salvianolic acid and tanshinone. However, their levels in cultivated S. miltiorrhiza are inferior to that of the wild herbs, so the production of high-quality medicinal herbs is sharply declining. Consequently, the utilization of beneficial endophytic fungi to improve the yield and quality of S. miltiorrhiza holds great significance for the cultivation of medicinal plants. In this study, nine non-pathogenic, endophytic fungal strains were introduced into sterile S. miltiorrhiza seedlings and cultivated both in vitro and in situ (the greenhouse). The effects of these strains on the growth indices, C and N metabolism, antioxidant activity, photosynthesis, and content of bioactive ingredients in S. miltiorrhiza were then evaluated. The results showed that the different genera, species, or strains of endophytic fungi regulated the growth and metabolism of S. miltiorrhiza in unique ways. These endophytic fungi primarily exerted their growth-promoting effects by increasing the net photosynthetic rate, intercellular CO2 concentration, and the activities of sucrose synthase, sucrose phosphate synthase, nitrate reductase, and glutamine synthetase. They also enhanced the adaptability and resistance to environmental stresses by improving the synthesis of osmoregulatory compounds and the activity of antioxidant enzymes. However, their regulatory effects on the growth and development of S. miltiorrhiza were affected by environmental changes. Moreover, the strains that significantly promoted the synthesis and accumulation of phenolic acids inhibited the accumulation of tanshinones components, and vice versa. The endophytic fungal strains Penicillium meloforme DS8, Berkeleyomyces basicola DS10, and Acremonium sclerotigenum DS12 enhanced the bioaccumulation of tanshinones. Fusarium solani DS16 elevated the rosmarinic acid content and yields in S. miltiorrhiza. The strain Penicillium javanicum DS5 improved the contents of dihydrotanshinone, salvianolic acid B, and rosmarinic acid. The strains P. meloforme DS8 and B. basicola DS10 improved resistance. Various endophytic fungi affected the quality and yield of S. miltiorrhiza by regulating different physiological and metabolic pathways. This study also provides a novel and effective method to maximize the effects of beneficial endophytic fungi by selecting specific strains to design microbial communities based on the different ecological functions of endophytic fungi under varying environments and for specific production goals.

Enhancement of specialized metabolites using CRISPR/Cas gene editing technology in medicinal plants.

Plants are the richest source of specialized metabolites. The specialized metabolites offer a variety of physiological benefits and many adaptive evolutionary advantages and frequently linked to plant defense mechanisms. Medicinal plants are a vital source of nutrition and active pharmaceutical agents. The production of valuable specialized metabolites and bioactive compounds has increased with the improvement of transgenic techniques like gene silencing and gene overexpression. These techniques are beneficial for decreasing production costs and increasing nutritional value. Utilizing biotechnological applications to enhance specialized metabolites in medicinal plants needs characterization and identification of genes within an elucidated pathway. The breakthrough and advancement of CRISPR/Cas-based gene editing in improving the production of specific metabolites in medicinal plants have gained significant importance in contemporary times. This article imparts a comprehensive recapitulation of the latest advancements made in the implementation of CRISPR-gene editing techniques for the purpose of augmenting specific metabolites in medicinal plants. We also provide further insights and perspectives for improving metabolic engineering scenarios in medicinal plants.

Antimicrobial Activity of Secondary Metabolites in Medicinal Plants: An Update

Plants have filled in as a significant wellspring of elements for conventional drugs for centuries. Verifiable records and present day ethno botanical field examines feature their significance in the conventional treatment of irresistible malady. Be that as it may, plants form just a minor level of present collection of FDA-endorsed antimicrobial medications. The present article gives an outline of active components of plants as hint for other wellspring of antimicrobial agents to be used in the battle against microscopic organisms. It additionally surveys the ethno botanical way to deal with sedate disclosure and talks about various inventive focuses for future medication revelation endeavours in this field. Without an uncertainty, antimicrobials are miracle tranquilizers. They have represented a very long time against different irresistible infections and spared a huge number of lives. The ongoing disappointment of antimicrobials because of the sensational rise of multidrug-safe microbes and fast spread of new diseases, be that as it may, prompts wellbeing associations and the pharmaceutical business worldwide to change their methodology and to expand improvement of antimicrobials against quickly rising anti-infection safe microorganisms. In spite of the fact that there is thinking about elective wellsprings of characteristic antimicrobial molecules from plants having different methods of activity, some of which have been utilized in regular medication for a considerable length of time and have appeared to have serious impacts contrasted with other antimicrobials. This examination portrays plant intensity as an elective hotspot for antimicrobial agents.

Effects of fungal endophytes and arbuscular mycorrhizal fungi on growth of Echium vulgare and alkannin/shikonin and their derivatives production in roots

Endophytic fungi as well as arbuscular mycorrhizal fungi (AMF) are known to stimulate plant growth and production of secondary metabolites in medicinal plants. Here, 10 endophytic fungi isolated from roots of wild Alkanna tinctoria plants and 5 AMF purchased from the Glomeromycota in vitro collection were evaluated, during two successive three-month greenhouse experiments, on the growth of Echium vulgare and alkannin/shikonin and their derivatives (A/Sd) production in the roots. Some of the endophytic fungi tested significantly increased plant growth parameters as compared to the control: Cladosporium allicinum, Cadophora sp., Clonostachys sp., Trichoderma hispanicum and Leptosphaeria ladina increased root volume, Plectosphaerella sp. And T. hispanicum root fresh weight and root water retention and T. hispanicum plant water retention. However, none of these fungi impacted A/Sd production. Conversely, none of the AMF strains tested impacted plant growth parameters, but those inoculated with Rhizophagus intraradices MUCL 49410 had a significantly higher concentration of alkannin/shikonin (A/S), acetyl-A/S, β,β– dimethylacryl-A/S, isovaleryl-A/S and total A/Sd, compared to the control plants. Further studies are needed to investigate the mechanisms involved in the production of A/Sd in plants associated to specific endophytic fungi/AMF and on the cultivation conditions required for optimal production of these compounds.

Optimization and Characterization of Phenolic Extraction Conditions and Antioxidant Activity Evaluation of Adenanthera pavonina L. Bark.

The presence of high levels of secondary metabolites in medicinal plants can significantly influence the progress of drug development. Here, we aimed to maximize phenolic extraction from Adenanthera pavonina L. stem bark using various solvents such as ethyl acetate, methanol, petroleum ether, and chloroform. A response surface method (RSM) with a central composite design (CCD) statistical technique was applied to optimize the extraction process, employing three important extracting parameters such as extraction time (h), temperature (°C), and solvent composition (% v/v of methanol/water) to obtain the highest phenolic content. Total phenolic content (TPC) and antioxidant activity (IC50 of extract's DPPH radical scavenging activity) were used as response variables to find the influence of these extracting parameters. Among the various solvents used, methanol extract showed the highest contents of phenolics and the maximum level of antioxidant activity with a lower IC50 value. The notable TPC and IC50 value of the extract's DPPH radical scavenging capacity were found to be 181.69 ± 0.20 mg GAE/g dry tissue and 60.13 ± 0.11 mg/mL, respectively, under the optimal conditions with a solvent composition of 71.61% (v/v) of methanol/water, extraction temperature of 42.52 °C, and extraction time of 24 h. The optimized extract of A. pavonina stem bark was further subjected to HPLC analysis, where six phenolic compounds, including coumarin, p-coumaric acid, chlorogenic acid, sinapic acid, gallic acid, and caffeic acid, were identified along with their respective quantities. Overall, the findings of this study uncover a low-cost analytical model for maximizing phenolic extraction from A. pavonina bark with enhanced antioxidant activity.

Exogenous melatonin differentially affects biomass, total carbohydrates, and essential oil production in peppermint upon simultaneous exposure to chitosan-coated Fe3O4 NPs

Melatonin and iron play important roles in the growth processes and production of secondary metabolites in medicinal plants. To evaluate the effects of melatonin and Chitosan-Coated Iron Oxide Nanoparticles (Fe-CTs NPs) on peppermint growth, essential oil content and constituents, total carbohydrates and antioxidant enzyme activities, a factorial experiment was conducted based on randomized complete block design (CRBD) with three replications (n = 3). Treatments consisted of different concentrations of melatonin (0, 100, and 200 mg L−1) and Fe-CTs NPs (0, 7.5, and 15 mg L−1). During the experiment, foliar applications of melatonin and Fe-CTs NPs were performed three times with 20 days’ interval. Treatments with melatonin, and Fe-CTs NPs had significant effects on the studied traits. The results showed that with increasing melatonin and Fe-CTs NPs concentrations, fresh and dry weights, total carbohydrates, and leaf area index were significantly (P < 0.05) increased in treated plants. The highest CAT and APX activities were observed in plants treated with melatonin at 100 mg L−1 and Fe-CTs NPs at 15 mg L−1. Eucalyptol, Menthyl acetate, Thiophene, 2-ethyl-5-(2-methylpropyl), Mint furanone, and Viridiflorol were found as the major essential oil constituents in peppermint plants under experimental treatments. Moreover, analytical results showed that the highest amount of Menthol (38.48 %) was obtained in plants exposed to Fe-CTs NPs at 7.5 mg L−1, however, the highest L-Menthone (30.53 %) was observed in plants treated with melatonin at 200 mg L−1 and Fe-CTs NPs at 15 mg L−1. The findings provide insights into the regulatory mechanisms of melatonin and Fe-CTs NPs on peppermint growth, physiology and biosynthesis of volatile compounds.

Genome sequencing provides potential strategies for drug discovery and synthesis

Medicinal plants are renowned for their abundant production of secondary metabolites, which exhibit notable pharmacological activities and great potential for drug development. The biosynthesis of secondary metabolites is highly intricate and influenced by various intrinsic and extrinsic factors, resulting in substantial species diversity and content variation. Consequently, precise regulation of secondary metabolite synthesis is of utmost importance. In recent years, genome sequencing has emerged as a valuable tool for investigating the synthesis and regulation of secondary metabolites in medicinal plants, facilitated by the widespread use of high-throughput sequencing technologies. This review highlights the latest advancements in genome sequencing within this field and presents several strategies for studying secondary metabolites. Specifically, the article elucidates how genome sequencing can unravel the pathways for secondary metabolite synthesis in medicinal plants, offering insights into the functions and regulatory mechanisms of participating enzymes. Comparative analyses of plant genomes allow identification of shared pathways of metabolite synthesis among species, thereby providing novel avenues for obtaining cost-effective biosynthetic intermediates. By examining individual genomic variations, genes or gene clusters associated with the synthesis of specific compounds can be discovered, indicating potential targets and directions for drug development and the exploration of alternative compound sources. Moreover, the advent of gene-editing technology has enabled the precise modifications of medicinal plant genomes. Optimization of specific secondary metabolite synthesis pathways becomes thus feasible, enabling the precise editing of target genes to regulate secondary metabolite production within cells. These findings serve as valuable references and lessons for future drug development endeavors, conservation of rare resources, and the exploration of new resources.

Intraspecific divergence in essential oil content, composition and genes expression patterns of monoterpene synthesis in Origanum vulgare subsp. vulgare and subsp. gracile under salinity stress

BackgroundOregano (Origanum vulgare L.), one of the important medicinal plants in the world, has valuable pharmacological compounds with antimicrobial, antiviral, antioxidant, anti-inflammatory, antispasmodic, antiurolithic, antiproliferative and neuroprotective activities. Phenolic monoterpenes such as thymol and carvacrol with many medical importance are found in Oregano essential oil. The biosynthesis of these compounds is carried out through the methyl erythritol-4 phosphate (MEP) pathway. Environmental stresses such as salinity might improve the secondary metabolites in medicinal plants. The influence of salinity stress (0 (control), 25, 50 and 100 mM NaCl) on the essential oil content, composition and expression of 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR), γ-terpinene synthase (Ovtps2) and cytochrome P450 monooxygenases (CYP71D180) genes involved in thymol and carvacrol biosynthesis, was investigated in two oregano subspecies (vulgare and gracile).ResultsEssential oil content was increased at low NaCl concentration (25 mM) compared with non-stress conditions, whereas it was decreased as salinity stress intensified (50 and 100 mM). Essential oil content was significantly higher in subsp. gracile than subsp. vulgare. The highest (0.20 mL pot−1) and lowest (0.06 mL pot−1) amount of essential oil yield was obtained in subsp. gracile at 25 and 100 mM NaCl, respectively. The content of carvacrol, as the main component of essential oil, decreased with increasing salinity level in subsp. gracile, but increased in subsp. vulgare. The highest expression of DXR, Ovtps2 and CYP71D180 genes was observed at 50 mM NaCl in subsp. vulgare. While, in subsp. gracile, the expression of the mentioned genes decreased with increasing salinity levels. A positive correlation was obtained between the expression of DXR, Ovtps2 and CYP71D180 genes with carvacrol content in both subspecies. On the other hand, a negative correlation was found between the expression of CYP71D180 and carvacrol content in subsp. gracile.ConclusionsThe findings of this study demonstrated that both oregano subspecies can tolerate NaCl salinity up to 50 mM without significant reduction in essential oil yield. Also, moderate salinity stress (50 mM NaCl) in subsp. vulgare might increase the carvacrol content partly via increment the expression levels of DXR, Ovtps2 and CYP71D180 genes.

Advances in DNA methylation and demethylation in medicinal plants: a review.

DNA methylation and demethylation are widely acknowledged epigenetic phenomena which can cause heritable and phenotypic changes in functional genes without changing the DNA sequence. They can thus affect phenotype formation in medicinal plants. However, a comprehensive review of the literature summarizing current research trends in this field is lacking. Thus, this review aims to provide an up-to-date summary of current methods for the detection of 5-mC DNA methylation, identification and analysis of DNA methyltransferases and demethyltransferases, and regulation of DNA methylation in medicinal plants. The data showed that polyploidy and environmental changes can affect DNA methylation levels in medicinal plants. Changes in DNA methylation can thus regulate plant morphogenesis, growth and development, and formation of secondary metabolites. Future research is required to explore the mechanisms by which DNA methylation regulates the accumulation of secondary metabolites in medicinal plants.

Utilizing X-ray fluorescence (XRF) method to evaluate the content of metal elements in soil and their effects on the total phenolic and flavonoid contents of some medicinal plants.

Soil factors, especially metal elements in the soil, play a significant role in forming and accumulating secondary metabolites, which determine the medicinal properties of medicinal herbs. In this study, the concentrations of some metal elements (K, Mn, Fe, Cu, Zn, and Cr) in Cam Mountain and Tinh Bien Town, An Giang Province, Vietnam, were determined using the XRF method. We simultaneously determined the total phenolic and flavonoid content of some medicinal herbs collected from the collected soil sample areas, thereby assessing the influence of these elements on the formation of secondary metabolites in medicinal plants. The results showed that K, Mn, and Cr were mainly concentrated in the topsoil and transition layers; Fe and Cu elements tended to concentrate in the transition layer and the subsoil when surveying the soil profile. K, Mn, Cu, and Cr concentrations were more focused in Tinh Bien area, while Fe and Zn had higher concentrations at Cam Mountain. Additionally, results from evaluating the relationship between the content of the elements in the soil and the content of two active compounds also showed the correlation regression model between Zn and flavonoid expression by level 4 at the 5% significance level. Thus, the nonlinear model is suitable for evaluating the relationship between the content of metal elements in the soil and the active compound in medicinal plants.

Endophytic fungi mediates production of bioactive secondary metabolites via modulation of genes involved in key metabolic pathways and their contribution in different biotechnological sector.

Endophytic fungi stimulate the production of an enormous number of bioactive metabolites in medicinal plants and affect the different steps of biosynthetic pathways of these secondary metabolites. Endophytic fungi possess a number of biosynthetic gene clusters that possess genes for various enzymes, transcription factors, etc., in their genome responsible for the production of secondary metabolites. Additionally, endophytic fungi also modulate the expression of various genes responsible for the synthesis of key enzymes involved in metabolic pathways of such as HMGR, DXR, etc. involved in the production of a large number of phenolic compounds as well as regulate the expression of genes involved in the production of alkaloids and terpenoids in different plants. This review aims to provide a comprehensive overview of gene expression related to endophytes and their impact on metabolic pathways. Additionally, this review will emphasize the studies done to isolate these secondary metabolites from endophytic fungi in large quantities and assess their bioactivity. Due to ease in synthesis of secondary metabolites and their huge application in the medical industry, these bioactive metabolites are now being extracted from strains of these endophytic fungi commercially. Apart from their application in the pharmaceutical industry, most of these metabolites extracted from endophytic fungi also possess plant growth-promoting ability, bioremediation potential, novel bio control agents, sources of anti-oxidants, etc. The review will comprehensively shed a light on the biotechnological application of these fungal metabolites at the industrial level.

Methyl jasmonate and salicylic acid as powerful elicitors for enhancing the production of secondary metabolites in medicinal plants: an updated review.

Plant secondary metabolites are bioactive scaffolds that are crucial for plant survival in the environment and to maintain a defense mechanism from predators. These compounds are generally present in plants at a minimal level and interestingly, they are found to have a wide variety of therapeutic values for humans. Several medicinal plants are used for pharmaceutical purposes due to their affordability, fewer adverse effects, and vital role in traditional remedies. Owing to this reason, these plants are exploited at a high range worldwide and therefore many medicinal plants are on the threatened list. There is a need of the hour to tackle this major problem, one effective approach called elicitation can be used to enhance the level of existing and novel plant bioactive compounds using different types of elicitors namely biotic and abiotic. This process can be generally achieved by in vitro and in vivo experiments. The current comprehensive review provides an overview of biotic and abiotic elicitation strategies used in medicinal plants, as well as their effects on secondary metabolites enhancement. Further, this review mainly deals with the enhancement of biomass and biosynthesis of different bioactive compounds by methyl jasmonate (MeJA) and salicylic acid (SA) as elicitors of wide medicinal plants in in vitro by using different cultures. The present review was suggested as a significant groundwork for peers working with medicinal plants by applying elicitation strategies along with advanced biotechnological approaches.

Ultraviolet-B and Heavy Metal-Induced Regulation of Secondary Metabolites in Medicinal Plants: A Review.

Despite a rich history and economic importance, the potential of medicinal plants has not been fully explored under different abiotic stress conditions. Penetration of UV-B radiation and contamination of heavy metals are two important environmental stress for plants with remarkable influence on the defense-related and pharmaceutically important secondary metabolites of medicinal plants. UV-B and heavy metal contamination may become a critical issue that either positively or negatively affects the quality and quantity of secondary metabolites. Such effects may result from changes in the expression level of genes that encode the corresponding enzymes or the inactivation and/or stimulation of specific enzymes involved in the different biosynthetic pathways of the secondary metabolites. Therefore, a comprehensive study of the impact of UV-B and heavy metals individually and in combination on the biosynthesis and accumulation of secondary metabolites in medicinal plants is discussed in the present review.

Responses of Colchicum speciosum L. populations to conventional and nano-fertilizers of nitrogen through changes in morphological and biochemical attributes

There is an increasing interest in the use of nano-fertilizer as an alternative to traditional fertilizers, in order to increase the secondary metabolites in medicinal plants. The present study was conducted to observe the changes in morphological and biochemical properties of three populations of Colchicum speciosum L., from Iran (Filband, Sangdarka, and Kelerd), upon conventional (1.1 and 2.2 mg L-1) and nano-N (1.5 and 3 mg L-1) fertilizers based on completely randomized design (CRD). The anthocyanin and phenolic contents of leaves and corms were determined with a spectrophotometer and corm colchicine was extracted by high-performance liquid chromatography (HPLC). The results represented different responses of morphological and biochemical attributes to populations due to their different origins. Filband with higher altitude showed increased leaf area, plant length, corn weight and diameter when treated with N fertilizers. Increased total phenolic component (TPC) in leaves and corm and also leaf total flavonoids component (TFC) were reported in Filband upon N fertilizers. All fertilizers led to decreased leaf anthocyanin when N fertilizers were applied. A noticeable increase in colchicine was obtained in Kelerd and Sangdarka when plants were treated with 1.5 mg L-1 nano-N fertilizer. Heat map analysis of corm anthocyanin, leaf anthocyanin, leaf TPC, leaf TPC, and colchicine amount showed higher variability under the treatments. According to principal component analysis (PCA), corm TPC, leaf TFC, corm TFC, leaf area, and corm weight were specific traits of Kelerd. In conclusion, different responses of morphological and biochemical traits were reported between populations, and N fertilizers exerted diverse effects on these traits. The population from higher altitudes showed higher phenolic content and lower anthocyanin accumulation under conventional and nano-N fertilizers.

Microbial fortification of pharmacological metabolites in medicinal plants

Medicinal plants are rich in secondary metabolites with beneficial pharmacological effects. The production of plant secondary metabolites is subjected to the influences by environmental factors including the plant-associated microbiome, which is crucial to the host’s fitness and survival. As a result, research interests are increasing in exploiting microbial capacities for enhancing plant production of pharmacological metabolites. A growing body of recent research provides accumulating evidence in support of developing microbe-based tools for achieving this objective. This mini review presents brief summaries of recent studies on medicinal plants that demonstrate microbe-augmented production of pharmacological terpenoids, polyphenols, and alkaloids, followed by discussions on some key questions beyond the promising observations. Explicit molecular insights into the underlying mechanisms will enhance microbial applications for metabolic fortification in medicinal plants.

Phytochemical and physiological reactions of feverfew (Tanacetum parthenium (L.) Schultz Bip) to TiO2 nanoparticles

Nanomaterials can be used as elicitors for improving the biosynthesis of secondary metabolites in medicinal plants. The present study was conducted to assay the titanium dioxide-nanoparticles (TiO2-NPs) effects on feverfew (Tanacetum parthenium) as an anti-cancer plant. The study showed that TiO2-NPs application increased the amounts of the main compounds and oxygenated monoterpene in essential oils, thereby causing an improvement in the quantity and quality of the essential oils compared to control. The highest effect was related to 1500 ppm TiO2-NPs concentration. Regarding parthenolide, TiO2-NPs had no positive effect on parthenolide content and the highest content was observed in control. Increasing the concentrations over 1500 ppm resulted in a decrease in chlorophyll content, capitule diameter, flower yield, and harvest index compared to other concentrations and control. Additionally, the results indicated that TiO2-NPs foliar spray reduced flower number, biological yield, fresh weight, and dry weights compared with untreated plants. The increase in quality and content of essential oil and lack of increase in parthenolide content, and reproductive and vegetative characteristics showed that TiO2-NPs mainly affected the content and composition of essential oil. Totally, the application of TiO2-NPs in terms of positive effect on the yield and metabolites (without damaging biological effects) can be recommended and followed up to the concentration of 1000 ppm. Overall, the results indicated that improving the synthesis of valuable medicinal metabolites using TiO2-NPs has promising results depending on the type of species, concentration used and target metabolites.