Tilting Plant Metabolism for Improved Metabolite Biosynthesis and Enhanced Human Benefit

Cytotoxic activity of callus extract from Vachellia farnesiana (L) Wight & Arn

The in vitro cultures of Vachellia farnesiana (L) Wight & Arn. have demonstrated cytotoxic activity through callus extract on the HeLa cell line. Explants excised from in vitro-grown seedlings from seeds of two different locations were inoculated on Murashige and Skoog (MS) culture media containing various concentrations of N-6 benzyladenine (BA) or kinetin with 2,4-dichlorophenoxyacetic acid (2,4-D). Optimal efficiency in friable callus induction (100%) was achieved in leaf explants cultured on MS media containing 2.32 µM BA + 13.57 µM 2,4-D. Plant tissues (callus and leaf) were extracted and subjected to quantitative phytochemical analysis, revealing the highest total alkaloid and phenolic content in leaf extracts from Queretaro adult specimens (339.5 ± 20.9 mg atropine equivalents (AE) per g dry extract (DE) and 158.4 ± 12.5 mg gallic acid equivalents (GAE) per g DE, respectively). In contrast, callus cultures exhibited significantly higher total triterpene content (356-381 mg ursolic acid equivalents (UAE) per g DE) compared to leaf extracts (208-243 mg UAE/g DE). Both leaf and callus extracts displayed cytotoxic activity against the HeLa cell line, with a significantly lower half-maximal inhibitory concentration (IC50) for leaf extracts (28-32 µg/mL) compared to callus cultures (43-66 µg/mL), suggesting that alkaloids were primarily responsible for the cytotoxic activity. Furthermore, this study provides valuable insights into the controlled production of bioactive compounds with cytotoxic activity, with callus serving as a rich source.

Climate-Affected Australian Tropical Montane Cloud Forest Plants: Metabolomic Profiles, Isolated Phytochemicals, and Bioactivities

The Australian Wet Tropics World Heritage Area (WTWHA) in northeast Queensland is home to approximately 18 percent of the nation's total vascular plant species. Over the past century, human activity and industrial development have caused global climate changes, posing a severe and irreversible danger to the entire land-based ecosystem, and the WTWHA is no exception. The current average annual temperature of WTWHA in northeast Queensland is 24 °C. However, in the coming years (by 2030), the average annual temperature increase is estimated to be between 0.5 and 1.4 °C compared to the climate observed between 1986 and 2005. Looking further ahead to 2070, the anticipated temperature rise is projected to be between 1.0 and 3.2 °C, with the exact range depending on future emissions. We identified 84 plant species, endemic to tropical montane cloud forests (TMCF) within the WTWHA, which are already experiencing climate change threats. Some of these plants are used in herbal medicines. This study comprehensively reviewed the metabolomics studies conducted on these 84 plant species until now toward understanding their physiological and metabolomics responses to global climate change. This review also discusses the following: (i) recent developments in plant metabolomics studies that can be applied to study and better understand the interactions of wet tropics plants with climatic stress, (ii) medicinal plants and isolated phytochemicals with structural diversity, and (iii) reported biological activities of crude extracts and isolated compounds.

Metabolomics of early blight (Alternaria solani) susceptible tomato (Solanum lycopersicum) unfolds key biomarker metabolites and involved metabolic pathways

Tomato (Solanum lycopersicum) is among the most important commercial horticultural crops worldwide. The crop quality and production is largely hampered due to the fungal pathogen Alternaria solani causing necrotrophic foliage early blight disease. Crop plants usually respond to the biotic challenges with altered metabolic composition and physiological perturbations. We have deciphered altered metabolite composition, modulated metabolic pathways and identified metabolite biomarkers in A. solani-challenged susceptible tomato variety Kashi Aman using Liquid Chromatography-Mass Spectrometry (LC-MS) based metabolomics. Alteration in the metabolite feature composition of pathogen-challenged (m/z 9405) and non-challenged (m/z 9667) plant leaves including 8487 infection-exclusive and 8742 non-infection exclusive features was observed. Functional annotation revealed putatively annotated metabolites and pathway mapping indicated their enrichment in metabolic pathways, biosynthesis of secondary metabolites, ubiquinone and terpenoid-quinones, brassinosteroids, steroids, terpenoids, phenylpropanoids, carotenoids, oxy/sphingolipids and metabolism of biotin and porphyrin. PCA, multivariate PLS-DA and OPLS-DA analysis showed sample discrimination. Significantly up regulated 481 and down regulated 548 metabolite features were identified based on the fold change (threshold ≥ 2.0). OPLS-DA model based on variable importance in projection (VIP scores) and FC threshold (> 2.0) revealed 41 up regulated discriminant metabolite features annotated as sphingosine, fecosterol, melatonin, serotonin, glucose 6-phosphate, zeatin, dihydrozeatin and zeatin-β-D-glucoside. Similarly, 23 down regulated discriminant metabolites included histidinol, 4-aminobutyraldehyde, propanoate, tyramine and linalool. Melatonin and serotonin in the leaves were the two indoleamines being reported for the first time in tomato in response to the early blight pathogen. Receiver operating characteristic (ROC)-based biomarker analysis identified apigenin-7-glucoside, uridine, adenosyl-homocysteine, cGMP, tyrosine, pantothenic acid, riboflavin (as up regulated) and adenosine, homocyctine and azmaline (as down regulated) biomarkers. These results could aid in the development of metabolite-quantitative trait loci (mQTL). Furthermore, stress-induced biosynthetic pathways may be the potential targets for modifications through breeding programs or genetic engineering for improving crop performance in the fields.

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.

The Cytotoxic Properties of Extreme Fungi's Bioactive Components-An Updated Metabolic and Omics Overview

Fungi are the most diverse living organisms on planet Earth, where their ubiquitous presence in various ecosystems offers vast potential for the research and discovery of new, naturally occurring medicinal products. Concerning human health, cancer remains one of the leading causes of mortality. While extensive research is being conducted on treatments and their efficacy in various stages of cancer, finding cytotoxic drugs that target tumor cells with no/less toxicity toward normal tissue is a significant challenge. In addition, traditional cancer treatments continue to suffer from chemical resistance. Fortunately, the cytotoxic properties of several natural products derived from various microorganisms, including fungi, are now well-established. The current review aims to extract and consolidate the findings of various scientific studies that identified fungi-derived bioactive metabolites with antitumor (anticancer) properties. The antitumor secondary metabolites identified from extremophilic and extremotolerant fungi are grouped according to their biological activity and type. It became evident that the significance of these compounds, with their medicinal properties and their potential application in cancer treatment, is tremendous. Furthermore, the utilization of omics tools, analysis, and genome mining technology to identify the novel metabolites for targeted treatments is discussed. Through this review, we tried to accentuate the invaluable importance of fungi grown in extreme environments and the necessity of innovative research in discovering naturally occurring bioactive compounds for the development of novel cancer treatments.

Molecular and genetic insights into secondary metabolic regulation underlying insect-pest resistance in legumes

Insect pests pose a major threat to agricultural production, resulting in significant economic losses for countries. A high infestation of insects in any given area can severely reduce crop yield and quality. This review examines the existing resources for managing insect pests and highlights alternative eco-friendly techniques to enhance insect pest resistance in legumes. Recently, the application of plant secondary metabolites has gained popularity in controlling insect attacks. Plant secondary metabolites encompass a wide range of compounds such as alkaloids, flavonoids, and terpenoids, which are often synthesized through intricate biosynthetic pathways. Classical methods of metabolic engineering involve manipulating key enzymes and regulatory genes to enhance or redirect the production of secondary metabolites in plants. Additionally, the role of genetic approaches, such as quantitative trait loci mapping, genome-wide association (GWAS) mapping, and metabolome-based GWAS in insect pest management is discussed, also, the role of precision breeding, such as genome editing technologies and RNA interference for identifying pest resistance and manipulating the genome to develop insect-resistant cultivars are explored, highlighting the positive contribution of plant secondary metabolites engineering-based resistance against insect pests. It is suggested that by understanding the genes responsible for beneficial metabolite compositions, future research might hold immense potential to shed more light on the molecular regulation of secondary metabolite biosynthesis, leading to advancements in insect-resistant traits in crop plants. In the future, the utilization of metabolic engineering and biotechnological methods may serve as an alternative means of producing biologically active, economically valuable, and medically significant compounds found in plant secondary metabolites, thereby addressing the challenge of limited availability.

The Role of Natural Flavonoids as Telomerase Inhibitors in Suppressing Cancer Growth

Cancer is a complex and multifaceted group of diseases characterized by the uncontrolled growth and spread of abnormal cells. While cancer can be challenging and life-altering, advances in research and development have led to the identification of new promising anti-cancer targets. Telomerase is one such target that is overexpressed in almost all cancer cells and plays a critical role in maintaining telomere length, which is essential for cell proliferation and survival. Inhibiting telomerase activity can lead to telomere shortening and eventual cell death, thus presenting itself as a potential target for cancer therapy. Naturally occurring flavonoids are a class of compounds that have already been shown to possess different biological properties, including the anti-cancer property. They are present in various everyday food sources and richly present in fruits, nuts, soybeans, vegetables, tea, wine, and berries, to name a few. Thus, these flavonoids could inhibit or deactivate telomerase expression in cancer cells by different mechanisms, which include inhibiting the expression of hTERT, mRNA, protein, and nuclear translocation, inhibiting the binding of transcription factors to hTERT promoters, and even telomere shortening. Numerous cell line studies and in vivo experiments have supported this hypothesis, and this development could serve as a vital and innovative therapeutic option for cancer. In this light, we aim to elucidate the role of telomerase as a potential anti-cancer target. Subsequently, we have illustrated that how commonly found natural flavonoids demonstrate their anti-cancer activity via telomerase inactivation in different cancer types, thus proving the potential of these naturally occurring flavonoids as useful therapeutic agents.

Antioxidant Green Factories: Toward Sustainable Production of Vitamin E in Plant In Vitro Cultures

Vitamin E is a dietary supplement synthesized only by photosynthetic organisms and, hence, is an essential vitamin for human well-being. Because of the ever-increasing demand for natural vitamin E and limitations in existing synthesis modes, attempts to improve its yield using plant in vitro cultures have gained traction in recent years. With inflating industrial production costs, integrative approaches to conventional bioprocess optimization is the need of the hour for multifold vitamin E productivity enhancement. In this review, we briefly discuss the structure, isomers, and important metabolic routes of biosynthesis for vitamin E in plants. We then emphasize its vital role in human health and its industrial applications and highlight the market demand and supply. We illustrate the advantages of in vitro plant cell/tissue culture cultivation as an alternative to current commercial production platforms for natural vitamin E. We touch upon the conventional vitamin E metabolic pathway engineering strategies, such as single/multigene overexpression and chloroplast engineering. We highlight the recent progress in plant systems biology to rationally identify metabolic bottlenecks and knockout targets in the vitamin E biosynthetic pathway. We then discuss bioprocess optimization strategies for sustainable vitamin E production, including media/process optimization, precursor/elicitor addition, and scale-up to bioreactors. We culminate the review with a short discussion on kinetic modeling to predict vitamin E production in plant cell cultures and suggestions on sustainable green extraction methods of vitamin E for reduced environmental impact. This review will be of interest to a wider research fraternity, including those from industry and academia working in the field of plant cell biology, plant biotechnology, and bioprocess engineering for phytochemical enhancement.

Evaluation of the effect of jasmonic acid elicitation on composition of pigments and biological activities in green callus of neem (Azadirachta indica)

This study was carried out with the aim of determining the effects of jasmonic acid (JA) elicitation on the bioactive pigments' biosynthesis and the antioxidant activities in green callus of Azadirachta indica of two different ages (4- and 8-week-old). Plant tissue culture technique was employed to induce the formation of green callus from leaf explants of A. indica on Murashige and Skoog (MS) medium supplemented with 0.6 mg/L thidiazuron (CM) and three different concentrations of JA (2, 4, and 6 mg/L). The methanolic extracts from the green callus were used for determination of total chlorophyll content (TCh), total carotenoid content (TC), total anthocyanin content (TAC), total phenolic content (TPC), and total flavonoid content (TFC) through colorimetric and HPLC analyses. The highest amount of yield was obtained from CM and 2 mg/L JA (2JA) extracts for 4- and 8-week-old samples, respectively. Phytochemical screening revealed the presence of alkaloids, flavonoids, phenols, tannins, and terpenoids in all 4- and 8-week-old samples elicited with 2, 4 and 6 mg/L JA. The highest value for TAC, TCh, TC, TPC, and TFC of 4- and 8-week-old samples were from callus cultured on media supplemented with 6 mg/L JA (6JA) and 4 mg/L JA (4JA), respectively. The lowest IC50 values were found to be 8.29 ± 0.10 mg/mL (6JA) for 4-week-old and 7.73 ± 0.03 mg/mL (4JA) for 8-week-old samples. The highest Ferric Reducing Antioxidant Power (FRAP) values obtained in this study were 90.60 ± 1.55 g/g (6JA), and 74.59 ± 3.91 g/g (4JA), respectively, for 4- and 8-week-old samples. Moreover, Pearson's correlation analysis revealed a significant correlation between TAC, TCh, TC, TPC, and TFC with ABTS and FRAP assays. In addition, PCA analysis revealed that 83.5% of the information (variances) contained in the data were retained by the first two principal components. Overall, these findings suggested that JA supplementation into the culture media significantly increase the chlorophyll, carotenoid, anthocyanin, phenolic and flavonoid contents and JA concentrations at 6 mg/L JA and 4 mg/L JA yielded the highest pigments content in 4- and 8-weeks-old callus, respectively.

Prospective Role of Indigenous Leafy Vegetables as Functional Food Ingredients

Indigenous leafy vegetables (ILVs) play a pivotal role in sustaining the lives of many people of low socio-economic status who reside in rural areas of most developing countries. Such ILVs contribute to food security since they withstand harsher weather and soil conditions than their commercial counterparts and supply important nutrients such as dietary fibre, vitamins and minerals. Furthermore, ILVs contain bioactive components such as phenolic compounds, flavonoids, dietary fibre, carotene content and vitamin C that confer health benefits on consumers. Several studies have demonstrated that regular and adequate consumption of vegetables reduces risks of chronic conditions such as diabetes, cancer, metabolic disorders such as obesity in children and adults, as well as cardiovascular disease. However, consumption of ILVs is very low globally as they are associated with unbalanced and poor diets, with being food for the poor and with possibly containing toxic heavy metals. Therefore, this paper reviews the role of ILVs as food security crops, the biodiversity of ILVs, the effects of processing on the bioactivity of ILVs, consumer acceptability of food derived from ILVs, potential toxicity of some ILVs and the potential role ILVs play in the future of eating.

Phenolic Acids as Antidepressant Agents

Depression is a psychiatric disorder affecting the lives of patients and their families worldwide. It is an important pathophysiology; however, the molecular pathways involved are not well understood. Pharmacological treatment may promote side effects or be ineffective. Consequently, efforts have been made to understand the molecular pathways in depressive patients and prevent their symptoms. In this context, animal models have suggested phytochemicals from medicinal plants, especially phenolic acids, as alternative treatments. These bioactive molecules are known for their antioxidant and antiinflammatory activities. They occur in some fruits, vegetables, and herbal plants. This review focused on phenolic acids and extracts from medicinal plants and their effects on depressive symptoms, as well as the molecular interactions and pathways implicated in these effects. Results from preclinical trials indicate the potential of phenolic acids to reduce depressive-like behaviour by regulating factors associated with oxidative stress, neuroinflammation, autophagy, and deregulation of the hypothalamic-pituitary-adrenal axis, stimulating monoaminergic neurotransmission and neurogenesis, and modulating intestinal microbiota.

Eco-biochemical responses, phytoremediation potential and molecular genetic analysis of Alhagi maurorum grown in metal-contaminated soils

BACKGROUND

Alhagi maurorum Medik. (camelthorn) is a dominant desert plant indigenous in various habitats, including the Western Desert of Egypt. The plant is especially prevalent in and around economic iron ore deposits. Nutrient and heavy metal levels in A. maurorum tissues and soil samples were assessed to identify associations between heavy metal levels in plants and soil. The objective was to evaluate this species as an indicator of heavy metal pollution. Photosynthetic pigments, protein, proline, alkaloids, flavonoids, 2,2-diphenyl-1-picrylhydrazylscavenging, reduced glutathione, malondialdehyde, antioxidant enzymes, and stress-related gene expression were assessed to determine their functional roles in metal stress adaptation in ultra- and molecular structure. Additionally, the molecular genetic variation in A. maurorum samples was assessed using co-dominant sequence-related amplified polymorphism (SRAP) and inter simple sequence repeats (ISSR).

RESULTS

A substantial difference in enzymatic and non-enzymatic antioxidants of A. maurorum was observed in samples collected from three sites. A. maurorum is suited to the climate in mineralized regions. Morphologically, the stem shows spines, narrow leaves, and a reduced shoot system. Anatomically, modifications included a cuticle coating on leaves and stems, sunken stomata, a compact epidermis, and a thick cortex. Significant anatomical-physiological differences were observed with varying heavy metal soil content, antioxidative enzyme activities increased as a tolerance strategy, and glutathione levels decreased in response to heavy metal toxicity. Heavy metal accumulation also affected the expression of stress-related genes. The highest levels of expression of GST, G6PDH, 6PGD, nitrate reductase 1, and sulfate transporter genes were found in plants collected from site A1. However, auxin-induced protein exhibited its highest expression in plants collected from A2. Six SRAP combinations yielded 25 scoreable markers with a polymorphism rate of 64%, and 5 ISSR markers produced 11 bands with a polymorphism rate of 36.36% for three A. maurorum genotypes. The ME1xEM7 primer combinations provided the most polymorphic information content and resolving power, making it the most useful primer for differentiating A. maurorum genotypes. SRAP markers exhibited a higher diversity index (0.24) than ISSR markers (0.16).

CONCLUSIONS

A. maurorum displayed adaptive characteristics for heavy metal sequestration from mining site soils and is proposed as a strong candidate for phytoremediation.

Production and Functionalities of Specialized Metabolites from Different Organic Sources

Medicinal plants are rich sources of specialized metabolites that are of great importance to plants, animals, and humans. The usefulness of active biological compounds cuts across different fields, such as agriculture, forestry, food processing and packaging, biofuels, biocatalysts, and environmental remediation. In recent years, research has shifted toward the use of microbes, especially endophytes (bacteria, fungi, and viruses), and the combination of these organisms with other alternatives to optimize the production and regulation of these compounds. This review reinforces the production of specialized metabolites, especially by plants and microorganisms, and the effectiveness of microorganisms in increasing the production/concentration of these compounds in plants. The study also highlights the functions of these compounds in plants and their applications in various fields. New research areas that should be explored to produce and regulate these compounds, especially in plants and microbes, have been identified. Methods involving molecular studies are yet to be fully explored, and next-generation sequencing possesses an interesting and reliable approach.

Genetic Manipulation and Bioreactor Culture of Plants as a Tool for Industry and Its Applications

In recent years, there has been a considerable increase in interest in the use of transgenic plants as sources of valuable secondary metabolites or recombinant proteins. This has been facilitated by the advent of genetic engineering technology with the possibility for direct modification of the expression of genes related to the biosynthesis of biologically active compounds. A wide range of research projects have yielded a number of efficient plant systems that produce specific secondary metabolites or recombinant proteins. Furthermore, the use of bioreactors allows production to be increased to industrial scales, which can quickly and cheaply deliver large amounts of material in a short time. The resulting plant production systems can function as small factories, and many of them that are targeted at a specific operation have been patented. This review paper summarizes the key research in the last ten years regarding the use of transgenic plants as small, green biofactories for the bioreactor-based production of secondary metabolites and recombinant proteins; it simultaneously examines the production of metabolites and recombinant proteins on an industrial scale and presents the current state of available patents in the field.

Variation in Phenolic Compounds and Antioxidant Activity of Various Organs of African Cabbage (Cleome gynandra L.) Accessions at Different Growth Stages

The presence of nutritional and health-benefiting compounds has increased awareness of orphan leafy vegetables such as Cleome gynandra (CG), whose phytochemicals vary among accessions and organs during growth. This study investigated the polyphenol accumulation and antioxidant activities (AOA) of eight CG accessions from the vegetative stage to the seed set stage. Plants were separated into leaves and stem (LS), flowers, and silique organs, and extracts were analyzed for total phenolic content (TPC), total flavonoid content (TFC), rutin and astragalin content, and AOA using 2,2-diphenyl-1-picrylhydrazyl-hydrate (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). There were significant interaction effects of growth stages and accessions that contributed to changes in compounds content and AOA. TPC accumulated in plant generative parts, whereas flavonoids accumulated in young plant organs. HPLC profiling revealed that rutin was the most abundant compound in all organs, with flowers having the highest levels, while astragalin was only found in flowers. Silique extracts, particularly accession KF-14, recorded the highest TPC, which corresponded to the strongest radical scavenging activity in ABTS and DPPH assays and a strong linear correlation. The germplasm contained accessions with significantly different and varying levels of bioactive compounds and AOA. These findings potentiate the exploitation of CG organs such as siliques for AOA, flowers for rutin and astragalin, and young shoots for flavonoids. Moreover, the significant accumulation of the compounds in particular accessions of the germplasms suggest that such superior accessions may be useful candidates in genetic breeding programs to improve CG vegetable.

Bio-Based Polyurethane Resins Derived from Tannin: Source, Synthesis, Characterisation, and Application

Tannins are soluble, astringent secondary phenolic metabolites generally obtained from renewable natural resources, and can be found in many plant parts, such as fruits, stems, leaves, seeds, roots, buds, and tree barks, where they have a protective function against bacterial, fungal, and insect attacks. In general, tannins can be extracted using hot water or organic solvents from the bark, leaves, and stems of plants. Industrially, tannins are applied to produce adhesives, wood coatings, and other applications in the wood and polymer industries. In addition, tannins can also be used as a renewable and environmentally friendly material to manufacture bio-based polyurethanes (bio-PUs) to reduce or eliminate the toxicity of isocyanates used in their manufacture. Tannin-based bio-PUs can improve the mechanical and thermal properties of polymers used in the automotive, wood, and construction industries. The various uses of tannins need to be put into perspective with regards to possible further advances and future potential for value-added applications. Tannins are employed in a wide range of industrial applications, including the production of leather and wood adhesives, accounting for almost 90% of the global commercial tannin output. The shortage of natural resources, as well as the growing environmental concerns related to the reduction of harmful emissions of formaldehyde or isocyanates used in the production of polyurethanes, have driven the industrial and academic interest towards the development of tannin-based bio-PUs as sustainable alternative materials with satisfactory characteristics. The aim of the present review is to comprehensively summarize the current state of research in the field of development, characterization, and application of tannin-derived, bio-based polyurethane resins. The successful synthesis process of the tannin-based bio-PUs was characterized by Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), MALDI-TOF mass spectrometry, and gel permeation chromatography (GPC) analyses.

Biotechnology for carbon capture and fixation: Critical review and future directions

To mitigate the growing threat of climate change and develop novel technologies that can eliminate carbon dioxide, the most abundant greenhouse gas derived from the flue gas stream of the fossil fuel-fired power stations, is momentous. The development of carbon capture and sequestration-based technologies may play a significant role in this regard. Carbon fixation mostly occurs by photosynthesizing plants as well as photo and chemoautotrophic microbes that turn the atmospheric carbon dioxide into organic materials via their enzymes. Biofuel can offer a sustainable solution for carbon mitigation. The pragmatic implementation of biofuel production processes is neither cost-effective nor has been proven safe over the long term. Searching for ways to enhance biofuel generation by the employment of genetic engineering is vital. Carbon biosequestration can help to curb the greenhouse effect. In addition, new genomic approaches, which are able to use gene-splicing biotechnology techniques and recombinant DNA technology to produce genetically modified organisms, can contribute to improvement in sustainable and renewable biofuel and biomaterial production from microorganisms. Biopolymers, Biosurfactants, and Biochars are suggested as sustainable future trends. This study aims to pave the way for implementing biotechnology methods to capture carbon and decrease the demand and consumption of fossil fuels as well as the emissions of greenhouse gases. Having a better image of microorganisms' potential role in carbon capture and storage can be prolific in developing powerful techniques to reduce CO₂ emissions.

Exogenous Putrescine Enhances Salt Tolerance and Ginsenosides Content in Korean Ginseng (Panax ginseng Meyer) Sprouts

The effect of exogenously applied putrescine (Put) on salt stress tolerance was investigated in Panax ginseng. Thirty-day-old ginseng sprouts were grown in salinized nutrient solution (150 mM NaCl) for five days, while the control sprouts were grown in nutrients solution. Putrescine (0.3, 0.6, and 0.9 mM) was sprayed on the plants once at the onset of salinity treatment, whereas control plants were sprayed with water only. Ginseng seedlings tested under salinity exhibited reduced plant growth and biomass production, which was directly interlinked with reduced chlorophyll and chlorophyll fluorescence due to higher reactive oxygen species (hydrogen peroxide; H2O2) and lipid peroxidation (malondialdehyde; MDA) production. Application of Put enhanced accumulation of proline, total soluble carbohydrate, total soluble sugar and total soluble protein. At the same time, activities of antioxidant enzymes like superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase in leaves, stems, and roots of ginseng seedlings were increased. Such modulation of physio-biochemical processes reduced the level of H2O2 and MDA, which indicates a successful adaptation of ginseng seedlings to salinity stress. Moreover, protopanaxadiol (PPD) ginsenosides enhanced by both salinity stress and exogenous Put treatment. On the other hand, protopanaxatriol (PPT) ginsenosides enhanced in roots and reduced in leaves and stems under salinity stress condition. In contrast, they enhanced by exogenous Put application in all parts of the plants for most cases, also evidenced by principal component analysis. Collectively, our findings provide an important prospect for the use of Put in modulating salinity tolerance and ginsenosides content in ginseng sprouts.

Substantial effect of phytochemical constituents against the pandemic disease influenza-a review

Background

Influenza is an acute respiratory tract infection caused by the influenza virus. Vaccination and antiviral drugs are the two methods opted to control the disease. Besides their efficiency, they also cause adverse side effects. Hence, scientists turned their attention to powerful herbal medicines. This review put focus on various proven, scientifically validated anti-influenza compounds produced by the plants suggested for the production of newer drugs for the better treatment of influenza and its related antiviral diseases too.

Main body

In this review, fifty medicinal herb phytochemical constituents and their anti-influenza activities have been documented. Specifically, this review brings out the accurate and substantiates mechanisms of action of these constituents. This study categorizes the phytochemical constituents into primary and secondary metabolites which provide a source for synthesizing and developing new drugs.

Conclusion

This article provides a summary of the actions of the herbal constituents. Since the mechanisms of action of the components are elucidated, the pandemic situation arising due to influenza and similar antiviral diseases can be handled promisingly with greater efficiency. However, clinical trials are in great demand. The formulation of usage may be a single drug compound or multi-herbal combination. These, in turn, open up a new arena for the pharmaceutical industries to develop innovative drugs.

The Genetic Base for Peanut Height-Related Traits Revealed by a Meta-Analysis

Peanut (Arachis hypogaea L.) is an important oilseed crop worldwide, and peanut height has been shown to be closely related to yield, therefore a better understanding of the genetic base of plant height-related traits may allow us to have better control of crop yield. Plant height-related traits are quantitative traits that are genetically controlled by many genes, and distinct quantitive trait loci (QTLs) may be identified for different peanut accessions/genotypes. In the present study, in order to gain a more complete picture of the genetic base for peanut height-related traits, we first make use of the high quality NGS sequence data for 159 peanut accessions that are available within our research groups, to carry out a GWAS study for searching plant height-related regions. We then perform a literature survey and collect QTLs for two plant height-related traits (Ph: peanut main stem height, and Fbl: the first branch length) from earlier related QTL/GWAS studies in peanut. In total, we find 74 and 21 genomic regions that are, associated with traits Ph and Fbl, respectively. Annotation of these regions found a total of 692 and 229 genes for, respectively, Ph and Fbl, and among those genes, 158 genes are shared. KEGG and GO enrichment analyses of those candidate genes reveal that Ph- and Fbl-associated genes are both enriched in the biosynthesis of secondary metabolites, some basic processes, pathways, or complexes that are supposed to be crucial for plant development and growth.

A mixture of quebracho and chestnut tannins drives butyrate-producing bacteria populations shift in the gut microbiota of weaned piglets

Weaning is a critical period for piglets, in which unbalanced gut microbiota and/or pathogen colonisation can contribute to diseases that interfere with animal performance. Tannins are natural compounds that could be used as functional ingredients to improve gut health in pig farming thanks to their antibacterial, antioxidant, and antidiarrhoeal properties. In this study, a mixture of quebracho and chestnut tannins (1.25%) was evaluated for its efficacy in reducing the negative weaning effects on piglet growth. Microbiota composition was assessed by Illumina MiSeq 16S rRNA gene sequencing of DNA extracted from stools at the end of the trial. Sequence analysis revealed an increase in the genera Shuttleworthia, Pseudobutyrivibrio, Peptococcus, Anaerostipes, and Solobacterium in the tannin-supplemented group. Conversely, this dietary intervention reduced the abundance of the genera Syntrophococcus, Atopobium, Mitsuokella, Sharpea, and Prevotella. The populations of butyrate-producing bacteria were modulated by tannin, and higher butyrate concentrations in stools were detected in the tannin-fed pigs. Co-occurrence analysis revealed that the operational taxonomic units (OTUs) belonging to the families Veillonellaceae, Lachnospiraceae, and Coriobacteriaceae occupied the central part of the network in both the control and the tannin-fed animals. Instead, in the tannin group, the OTUs belonging to the families Acidaminococcaceae, Alcaligenaceae, and Spirochaetaceae characterised its network, whereas Family XIII Incertae Sedis occupied a more central position than in the control group. Conversely, the presence of Desulfovibrionaceae characterised the network of the control group, and this family was not present in the network of the tannin group. Moreover, the prediction of metabolic pathways revealed that the gut microbiome of the tannin group possessed an enhanced potential for carbohydrate transport and metabolism, as well as a lower abundance of pathways related to cell wall/membrane/envelope biogenesis and inorganic ion transport. In conclusion, the tested tannins seem to modulate the gut microbiota, favouring groups of butyrate-producing bacteria.

Natural substances in cancer—do they work?

Owing to anticancer properties of selected natural substances, it is assumed that they have potential to be used in oncological therapy. Here, the recently proven effects of the selected natural polyphenols, resveratrol and curcumin, are described. Secondly, the potential of probiotics and prebiotics in modulation of immunological response and/or enhancing the chemotherapeutic treatments is reported based on the recent clinical trials. Further, the chapter presents current knowledge regarding the targeted supplementation of the patient with probiotic bacteria and known efficacy of probiotics to support immunotherapy. The major clinical trials are listed, aiming to verify whether, and to which extent the manipulation of patient’s microbiome can improve the outcome of chemotherapies. In the end, a potential of natural substances and feed ingredients to pose epigenetic changes is highlighted. The chapter provides an insight into the scientific proofs about natural bioactive substances in relation to cancer treatment, leaded by the question – do they really work?

Bioactive Compounds in Wild Nettle (Urtica dioica L.) Leaves and Stalks: Polyphenols and Pigments upon Seasonal and Habitat Variations

This study evaluated the presence of bioactives in wild nettle leaves and stalks during the phenological stage and in the context of natural habitat diversity. Thus, wild nettle samples collected before flowering, during flowering and after flowering from 14 habitats situated in three different regions (continental, mountain and seaside) were analyzed for low molecular weight polyphenols, carotenoids and chlorophylls using UPLC-MS/MS and HPLC analysis, while the ORAC method was performed for the antioxidant capacity measurement. Statistical analysis showed that, when compared to the stalks, nettle leaves contained significantly higher amounts of analyzed compounds which accumulated in the highest yields before flowering (polyphenols) and at the flowering stage (pigments). Moreover, nettle habitat variations greatly influenced the amounts of analyzed bioactives, where samples from the continental area contained higher levels of polyphenols, while seaside region samples were more abundant with pigments. The levels of ORAC followed the same pattern, being higher in leaves samples collected before and during flowering from the continental habitats. Hence, in order to provide the product's maximum value for consumers' benefit, a multidisciplinary approach is important for the selection of a plant part as well as its phenological stage with the highest accumulation of bioactive compounds.

Bioactive (Poly)phenols, Volatile Compounds from Vegetables, Medicinal and Aromatic Plants

Polyphenols, as well as volatile compounds responsible for aromatic features, play a critical role in the quality of vegetables and medicinal, and aromatic plants (MAPs). The research conducted in recent years has shown that these plants contain biologically active compounds, mainly polyphenols, that relate to the prevention of inflammatory processes, neurodegenerative diseases, cancers, and cardiovascular disorders as well as to antimicrobial, antioxidant, and antiparasitic properties. Throughout the years, many researchers have deeply studied polyphenols and volatile compounds in medicinal and aromatic plants, particularly those associated with consumer's choices or with their beneficial properties. In this context, the purpose of this review is to provide an overview of the presence of volatile and nonvolatile compounds in some of the most economically relevant and consumed vegetables and medicinal and aromatic plants, with an emphasis on bioactive polyphenols, polyphenols as prebiotics, and, also, the most important factors that affect the contents and profiles of the volatile and nonvolatile compounds responsible for the aromatic features of vegetables and MAPs. Additionally, the new challenges for science in terms of improving polyphenol composition and intensifying volatile compounds responsible for the positive characteristics of vegetables and medicinal and aromatic plants are reported.

Different carbon sources and their concentrations change alkaloid production and gene expression in Catharanthus roseus shoots in vitro

To compare the effects of different carbon sources on physiological aspects, especially medicinal alkaloid biosynthesis and related gene expression in Catharantus roseus (L.) G.Don, we employed sucrose and sorbitol with two concentrations (87.64 mM, the equimolar concentration of sucrose in MS basal medium, and 150 mM) on the plant's shoots in vitro in presence of 100 μM methyl jasmonate. The production of plant alkaloids including vincristine, vinblastine, ajmalicine, vindoline and catharantine and their biosynthetic and regulatory gene expression was measured. Both treatments had incremental effects on alkaloid production, upregulated the mitogen-activated protein kinase3 (MAPK3) and a downstream responsive transcription factor, ORCA3, which resulted in elevated transcript contents of the important genes in terpenoid indol alkaloids biosynthetic pathway including peroxidase1 (PRX1), geissoschizine synthase (GS), strictosidine synthase (STR) and deacetylvindoline acetyltransferase (DAT). Defensive responses such as antioxidant enzymes (catalase, peroxidase and superoxide dismutase) activities and non-enzymatic metabolites (total phenolics, flavonoids and carotenoids) contents increased under both treatments but the effects of sorbitol were stronger. Reduced fresh weight and chlorophylls contents, increased malondialdehyde (MDA) and carotenoid contents were shown after a week under all employed treatments. It seems that replacement of sucrose with sorbitol and also, increased concentrations of both carbon sources via increasing osmotic pressure make stressful conditions for the plant especially in longer times.

Effect of virus infection on the secondary metabolite production and phytohormone biosynthesis in plants

Plants have evolved according to their environmental conditions and continuously interact with different biological entities. These interactions induce many positive and negative effects on plant metabolism. Many viruses also associate with various plant species and alter their metabolism. Further, virus-plant interaction also alters the expression of many plant hormones. To overcome the biotic stress imposed by the virus's infestation, plants produce different kinds of secondary metabolites that play a significant role in plant defense against the viral infection. In this review, we briefly highlight the mechanism of virus infection, their influence on the plant secondary metabolites and phytohormone biosynthesis in response to the virus-plant interactions.

Physiological and Biochemical Changes in Sugar Beet Seedlings to Confer Stress Adaptability under Drought Condition

The present study was conducted to examine the adaptability of 11 sugar beet cultivars grown under drought stress in the controlled glasshouse. The treatment was initiated on 30-day-old sugar beet plants where drought stress was made withholding water supply for consecutive 10 days while control was done with providing water as per requirement. It was observed that drought stress expressively reduced plant growth, photosynthetic pigments, and photosynthetic quantum yield in all the cultivars but comparative better results were observed in S1 (MAXIMELLA), S2 (HELENIKA), S6 (RECODDINA), S8 (SV2347), and S11 (BSRI Sugarbeet 2) cultivars. Besides, osmolytes like proline, glycine betaine, total soluble carbohydrate, total soluble sugar, total polyphenol, total flavonoid, and DPPH free radical scavenging activity were remarkably increased under drought condition in MAXIMELLA, HELENIKA, TERRANOVA, GREGOIA, SV2348, and BSRI Sugar beet 2 cultivars. In contrast, activities of enzymes like superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were significantly decreased in all, while the cultivars SV2347, BSRI Sugar beet 1 and BSRI Sugar beet 2 were found with increased ascorbate peroxidase (APX) activity under drought condition. In parallel, polyphenol oxidase (PPO) was increased in all cultivars except HELENIKA. Overall, the cultivars HELENIKA, RECODDINA, GREGOIA, SV2347, SV2348, BSRI Sugar beet 1, and BSRI Sugar beet 2 were found best fitted to the given drought condition. These findings would help further for the improvement of stress adaptive sugar beet cultivars development in the breeding program for drought-prone regions.

Allithiamine Alleviates Hyperglycaemia-Induced Endothelial Dysfunction

Diabetes mellitus-related morbidity and mortality is a rapidly growing healthcare problem, globally. Several nutraceuticals exhibit potency to target the pathogenesis of diabetes mellitus. The antidiabetic effects of compounds of garlic have been extensively studied, however, limited data are available on the biological effects of a certain garlic component, allithiamine. In this study, allithiamine was tested using human umbilical cord vein endothelial cells (HUVECs) as a hyperglycaemic model. HUVECs were isolated by enzymatic digestion and characterized by flow cytometric analysis using antibodies against specific marker proteins including CD31, CD45, CD54, and CD106. The non-cytotoxic concentration of allithiamine was determined based on MTT, apoptosis, and necrosis assays. Subsequently, cells were divided into three groups: incubating with M199 medium as the control; or with 30 mMol/L glucose; or with 30 mMol/L glucose plus allithiamine. The effect of allithiamine on the levels of advanced glycation end-products (AGEs), activation of NF-κB, release of pro-inflammatory cytokines including IL-6, IL-8, and TNF-α, and H₂O₂-induced oxidative stress was investigated. We found that in the hyperglycaemia-induced increase in the level of AGEs, pro-inflammatory changes were significantly suppressed by allithiamine. However, allithiamine could not enhance the activity of transketolase, but it exerts a potent antioxidant effect. Collectively, our data suggest that allithiamine could alleviate the hyperglycaemia-induced endothelial dysfunction due to its potent antioxidant and anti-inflammatory effect by a mechanism unrelated to the transketolase activity.

Plant tissue culture as a perpetual source for production of industrially important bioactive compounds

Plants have been used throughout the world for its medicinal powers since ancient time. The pharmacological properties of plants are based on their phytochemical components especially the secondary metabolites which are outstanding sources of value added bioactive compounds. Secondary metabolites have complex chemical composition and are produced in response to various forms of stress to perform different physiological tasks in plants. They are used in pharmaceutical industries, cosmetics, dietary supplements, fragrances, flavors, dyes, etc. Extended use of these metabolites in various industrial sectors has initiated a need to focus research on increasing the production by employing plant tissue culture (PTC) techniques and optimizing their large scale production using bioreactors. PTC techniques being independent of climatic and geographical conditions will provide an incessant, sustainable, economical and viable production of secondary metabolites. This review article intends to assess the advantages of using plant tissue culture, distribution of important secondary metabolites in plant families, strategies involved for optimal metabolite production and the industrial importance of selected secondary metabolites.

Age-Dependent Metabolic Profiles Unravel the Metabolic Relationships Within and Between Flax Leaves (Linum usitatissimum)

Flax for oil seed is a crop of increasing popularity, but its cultivation needs technical improvement. Important agronomic traits such as productivity and resistance to stresses are to be regarded as the result of the combined responses of individual organs and their inter-communication. Ultimately, these responses directly reflect the metabolic profile at the cellular level. Above ground, the complexity of the plant phenotype is governed by leaves at different developmental stages, and their ability to synthesise and exchange metabolites. In this study, the metabolic profile of differently-developed leaves was used firstly to discriminate flax leaf developmental stages, and secondly to analyse the allocation of the metabolites within and between leaves. For this purpose, the concentration of 52 metabolites, both primary and specialized, was followed by gas chromatography (GC-) and liquid chromatography coupled to mass spectrometry (LC-MS) in alternate pairs of flax leaves. On the basis of their metabolic content, three populations of leaves in different growth stages could be distinguished. Primary and specialized metabolites showed characteristic distribution patterns, and compounds similarly evolving with leaf age could be grouped by the aid of the Kohonen self-organising map (SOM) algorithm. Ultimately, visualisation of the correlations between metabolites via hierarchical cluster analysis (HCA) allowed the assessment of the metabolic fluxes characterising different leaf developmental stages, and the investigation of the relationships between primary and specialized metabolites.

Phenolic and Non-Polar Fractions of the Extracts from Fruits, Leaves, and Twigs of Elaeagnus rhamnoides (L.) A. Nelson-The Implications for Human Barrier Cells

Biological potential of plant extracts are widely described. Because their oral or topical administration is usually recommended, intestinal mucous and skin are the first surfaces exposed to such preparations. Therefore, we asked the question whether phenolic and non-polar fractions of the extracts from fruits, twigs, and leaves of sea buckthorn (Elaeagnusrhamnoides (L.) A. Nelson) would be able to modulate the functions of human physiological barrier. The study was carried on caucasian colon epithelial-like Caco-2 cells and human foreskin fibroblasts HFF-1 line. Cell secretory activity (ELISA), the expression of cell surface molecules (flow cytometry), cell migration during wound healing in vitro (scratch assay) were assessed. It was demonstrated for the first time, that sea buckthorn extracts can improve intestinal and skin barrier by increasing of ICAM-1 expression on colon epithelial cells and intensification of IL-8 production by fibroblasts. On the other hand, an inhibition of fibroblasts migration in the presence of those preparations was noted. Therefore, greater attention should be paid on precise description of plant extracts effect depended on target cells and their role to give adequate recommendations for such preparations use.

Indole alkaloids: 2012 until now, highlighting the new chemical structures and biological activities

Indole alkaloids have attracted attention because of their therapeutic properties, being anti-inflammatory, antinociceptive, antitumoural, antioxidant and antimicrobial. These compounds present a wide structural diversity, which is directly related to the genera of the producing plants, as well as the biological activities. Indole alkaloids have attracted attention over the last decade because of this combination of bioactivity and structural diversity. Therefore, this review presented recent (2012-2018) advances in alkaloids, focusing on new compounds, extraction methods and biological activities. As such, approximately 70 articles were identified, which showed 261 new compounds produced by plants of the families Apocynaceae, Rubiaceae, Annonaceae and Loganiaceae. In addition, different extraction methods were identified, and the structures of the new compounds were analysed. In addition to indole molecules, there were mono-indole-, di-indole-, vinblastine-, vimblastine-, gelsedine-, geissospermidine-, koumine-, geissospermidine-, iboga-, perakine-, corynanthe-, vincamine-, ajmaline-, aspidorpema-, strychnos-type, β-carboline alkaloids and indole alkaloid glucosides. The reported biological activities are mainly anticancer, antibacterial, antimalarial, antifungal, antiparasitic, and antiviral, as well as anti-acetylcholinesterase and anti-butyrylcolinesterase properties. This review serves as a guide for those wishing to find the most recently identified alkaloid structures and their associated activities.

Transgenesis as a Tool for the Efficient Production of Selected Secondary Metabolites from in Vitro Plant Cultures

The plant kingdom abounds in countless species with potential medical uses. Many of them contain valuable secondary metabolites belonging to different classes and demonstrating anticancer, anti-inflammatory, antioxidant, antimicrobial or antidiabetic properties. Many of these metabolites, e.g., paclitaxel, vinblastine, betulinic acid, chlorogenic acid or ferrulic acid, have potential applications in medicine. Additionally, these compounds have many therapeutic and health-promoting properties. The growing demand for these plant secondary metabolites forces the use of new green biotechnology tools to create new, more productive in vitro transgenic plant cultures. These procedures have yielded many promising results, and transgenic cultures have been found to be safe, efficient and cost-effective sources of valuable secondary metabolites for medicine and industry. This review focuses on the use of various in vitro plant culture systems for the production of secondary metabolites.

Improvement of phytochemical production by plant cells and organ culture and by genetic engineering

Plants display an amazing ability to synthesize a vast array of secondary metabolites that are an inexhaustible source of phytochemicals, bioactive molecules some of which impact the human health. Phytochemicals present in medicinal herbs and spices have long been used as natural remedies against illness. Plant tissue culture represents an alternative to whole plants as a source of phytochemicals. This approach spares agricultural land that can be used for producing food and other raw materials, thus favoring standardized phytochemical production regardless of climatic adversities and political events. Over the past 20 years, different strategies have been developed to increase the synthesis and the extraction of phytochemicals from tissue culture often obtaining remarkable results. Moreover, the availability of genomics and metabolomics tools, along with improved recombinant methods related to the ability to overexpress, silence or disrupt one or more genes of the pathway of interest promise to open new exciting possibilities of metabolic engineering. This review provides a general framework of the cellular and molecular tools developed so far to enhance the yield of phytochemicals. Additionally, some emerging topics such as the culture of cambial meristemoid cells, the selection of plant cell following the expression of genes encoding human target proteins, and the bioextraction of phytochemicals from plant material have been addressed. Altogether, the herein described techniques and results are expected to improve metabolic engineering tools aiming at improving the production of phytochemicals of pharmaceutical and nutraceutical interest.

Stress and defense responses in plant secondary metabolites production

In the growth condition(s) of plants, numerous secondary metabolites (SMs) are produced by them to serve variety of cellular functions essential for physiological processes, and recent increasing evidences have implicated stress and defense response signaling in their production. The type and concentration(s) of secondary molecule(s) produced by a plant are determined by the species, genotype, physiology, developmental stage and environmental factors during growth. This suggests the physiological adaptive responses employed by various plant taxonomic groups in coping with the stress and defensive stimuli. The past recent decades had witnessed renewed interest to study abiotic factors that influence secondary metabolism during in vitro and in vivo growth of plants. Application of molecular biology tools and techniques are facilitating understanding the signaling processes and pathways involved in the SMs production at subcellular, cellular, organ and whole plant systems during in vivo and in vitro growth, with application in metabolic engineering of biosynthetic pathways intermediates.

Chemical and Morphological Inter- and Intrapopulation Variability in Natural Populations of Gentiana pneumonanthe L

Inter- and intrapopulation variability in six natural populations of the rare species Gentiana pneumonanthe was examined based on morphological and chemical data. Population size and linear morphometric parameters differed significantly among populations, but without a clear connection to habitat conditions, i. e. water supply and light availability. Leaf shape varied from ovate to lanceolate in all populations, and one population was distinctive in having the largest number of leaves of transitional shape. HPLC analyses of six secondary metabolites were performed separately for belowground parts, and aboveground vegetative and reproductive parts of individual plants (6 populations ×7 individuals ×3 plant parts, n=126) in order to examine differences at the population and individual levels. Three secoiridoids (swertiamarin (SWM), sweroside (SWZ), and gentiopicrin (GP)), one xanthone (mangiferin (MGF)), and two flavones (isoorientin (IO) and isovitexin (IV)) were detected and quantified in the analyzed samples: sweroside dominated in the aboveground reproductive part, mangiferin in the aboveground vegetative part, and gentiopicrin in the belowground part. At the population level, differences in contents of the analyzed chemicals among populations were significant only for a few metabolites. At the individual level, a pronounced organ-dependent distribution of secondary metabolites was revealed. The results of this study contribute to a better understanding of natural variability within populations of the rare and threatened G. pneumonanthe, and provide data on the contents and within-plant distribution of secondary metabolites, which are important as pharmacologically active compounds and may be useful for further biotechnological procedures regarding this species.

Solvent based optimization for extraction and stability of thymoquinone from Nigella sativa Linn. and its quantification using RP-HPLC

The Nigella sativa pharmacological properties are mainly ascribed to its volatile oil, of which thymoquinone is an important bioactive component. Surprisingly, till date, no standard formulation or thymoquinone rich N. sativa extract is under clinical use probably due to its poor extraction and lesser stability in the already used solvents. In the present investigation solubility, extraction, percent composition and total antioxidant activity from the seeds of N. sativa was explored using five solvents. An HPLC method was standardized in an isocratic system (C-18 column, flow rate of 1.0 ml/min, mobile phase-water:methanol: 30:70, detection wavelength-254 nm, retention time-8.77 min) for quantification of thymoquinone. To further confirm the presence of thymoquinone in the respective extracts absorbance spectra analysis has been carried out and compared with pure thymoquinone. Additionally total antioxidant activity of Nigella sativa extracts has been evaluated using ascorbic acid as standard. Our results showed maximum percentage yield in aqueous extract while methanol having the least yield and the ethanol, benzene and hexane extracts exhibited moderate yields. A linear standard calibration curve of thymoquinone showed R² as 0.999 and % RSD as 7.166. The HPLC analysis revealed maximum percentage composition of thymoquinone in the benzene extract, whereas in the hexane and methanol extracts the content was less. Aqueous and ethanol extracts displayed insignificant thymoquinone content. Absorbance spectra analysis confirms the presence of thymoquinone peak in the benzene, hexane and methanol extracts while aqueous and ethanol extracts showed minimal absorbance. Maximum total antioxidant activity was observed in the aqueous extract while minimum was observed in the methanolic extract. Weak positive (+ 0.3676) correlation was established between percent composition of thymoquinone and antioxidant activity among different extracts indicating that thymoquinone may not be the only factor for antioxidant activity, but other phytochemicals might also contribute. However, we for the first time demonstrated that the benzene extract of N. sativa has better solubility and percent composition of thymoquinone as compared to other solvents. It can be concluded that the solubility, differential composition of bioactive components among these extracts may have diverse effects on the total antiradical activity. Thus, our study provides insights on optimization and standardization of bioactive rich formulation of N. sativa.

Production of Plant Secondary Metabolites: Examples, Tips and Suggestions for Biotechnologists

Plants are sessile organisms and, in order to defend themselves against exogenous (a)biotic constraints, they synthesize an array of secondary metabolites which have important physiological and ecological effects. Plant secondary metabolites can be classified into four major classes: terpenoids, phenolic compounds, alkaloids and sulphur-containing compounds. These phytochemicals can be antimicrobial, act as attractants/repellents, or as deterrents against herbivores. The synthesis of such a rich variety of phytochemicals is also observed in undifferentiated plant cells under laboratory conditions and can be further induced with elicitors or by feeding precursors. In this review, we discuss the recent literature on the production of representatives of three plant secondary metabolite classes: artemisinin (a sesquiterpene), lignans (phenolic compounds) and caffeine (an alkaloid). Their respective production in well-known plants, i.e., Artemisia, Coffea arabica L., as well as neglected species, like the fibre-producing plant Urtica dioica L., will be surveyed. The production of artemisinin and caffeine in heterologous hosts will also be discussed. Additionally, metabolic engineering strategies to increase the bioactivity and stability of plant secondary metabolites will be surveyed, by focusing on glycosyltransferases (GTs). We end our review by proposing strategies to enhance the production of plant secondary metabolites in cell cultures by inducing cell wall modifications with chemicals/drugs, or with altered concentrations of the micronutrient boron and the quasi-essential element silicon.

Antimicrobial Activity, Phenolic Content, and Cytotoxicity of Medicinal Plant Extracts Used for Treating Dermatological Diseases and Wound Healing in KwaZulu-Natal, South Africa

Medicinal plants used for wound healing and skin diseases are the key to unlocking the doors to combating problematic skin diseases as resistance of pathogens to pharmaceuticals and allopathic management continues to increase. The study aimed at investigating the antimicrobial efficacies, phenolic content, and cytotoxicity effects of 11 medicinal plant extracts commonly used for treating skin conditions and wound healing in traditional medicine within KwaZulu-Natal. Eleven plant species were separated into different plant parts (bulbs, roots, leaves) and extracted with different solvents. The extracts were assessed for antimicrobial activity against six Gram-positive and seven Gram-negative bacterial strains and four fungi commonly associated with skin conditions using disc diffusion and microdilution techniques. The aqueous methanolic extracts were screened for phenolic content while cytotoxicity tests were performed on all extracts using the brine shrimp lethality and tetrazolium-based colorimetric (MTT) assays. Extracts from Aloe ferox, A. arborescens, and Hypericum aethiopicum were the most active against almost all of the tested bacterial and fungal strains. All plant species exhibited some degree of antimicrobial activity. Total phenolic levels, flavonoids and tannins were also higher for A. ferox, followed by A. arborescens and H. aethiopicum, respectively. The cytotoxicity results of all plant extracts were in the range of 90-100% survival after 24 h in the brine shrimp assay. Extracts considered lethal would demonstrate >50% shrimp death. The MTT cytotoxicity test yielded LC50 values of >1 mg/mL on all extracts indicating that they are not cytotoxic. The observed antimicrobial efficacy demonstrated by some plant species and the general lack of cytotoxic effects on all the tested extracts presents some promising and beneficial aspects of these medicinal plant extracts in the treatment of skin diseases and wound healing. The two Aloe species and H. aethiopicum were among the best extracts that exhibited consistently good antimicrobial activity and warrants further investigations and possible isolation of bioactive principles.

Secondary metabolites in plants: transport and self-tolerance mechanisms

Plants produce a host of secondary metabolites with a wide range of biological activities, including potential toxicity to eukaryotic cells. Plants generally manage these compounds by transport to the apoplast or specific organelles such as the vacuole, or other self-tolerance mechanisms. For efficient production of such bioactive compounds in plants or microbes, transport and self-tolerance mechanisms should function cooperatively with the corresponding biosynthetic enzymes. Intensive studies have identified and characterized the proteins responsible for transport and self-tolerance. In particular, many transporters have been isolated and their physiological functions have been proposed. This review describes recent progress in studies of transport and self-tolerance and provides an updated inventory of transporters according to their substrates. Application of such knowledge to synthetic biology might enable efficient production of valuable secondary metabolites in the future.

Cannabis sativa: The Plant of the Thousand and One Molecules

Cannabis sativa L. is an important herbaceous species originating from Central Asia, which has been used in folk medicine and as a source of textile fiber since the dawn of times. This fast-growing plant has recently seen a resurgence of interest because of its multi-purpose applications: it is indeed a treasure trove of phytochemicals and a rich source of both cellulosic and woody fibers. Equally highly interested in this plant are the pharmaceutical and construction sectors, since its metabolites show potent bioactivities on human health and its outer and inner stem tissues can be used to make bioplastics and concrete-like material, respectively. In this review, the rich spectrum of hemp phytochemicals is discussed by putting a special emphasis on molecules of industrial interest, including cannabinoids, terpenes and phenolic compounds, and their biosynthetic routes. Cannabinoids represent the most studied group of compounds, mainly due to their wide range of pharmaceutical effects in humans, including psychotropic activities. The therapeutic and commercial interests of some terpenes and phenolic compounds, and in particular stilbenoids and lignans, are also highlighted in view of the most recent literature data. Biotechnological avenues to enhance the production and bioactivity of hemp secondary metabolites are proposed by discussing the power of plant genetic engineering and tissue culture. In particular two systems are reviewed, i.e., cell suspension and hairy root cultures. Additionally, an entire section is devoted to hemp trichomes, in the light of their importance as phytochemical factories. Ultimately, prospects on the benefits linked to the use of the -omics technologies, such as metabolomics and transcriptomics to speed up the identification and the large-scale production of lead agents from bioengineered Cannabis cell culture, are presented.

Antimicrobial, Anthelmintic Activities and Characterisation of Functional Phenolic Acids of Achyranthes aspera Linn.: A Medicinal Plant Used for the Treatment of Wounds and Ringworm in East Africa

Achyranthes aspera Linn. (Amaranthaceae) commonly known as Prickly Chaff flower (English) is traditionally used for treating a number of ailments. Different parts of the plant are used in treating wounds and ringworm in East Africa and elsewhere for a number of ailments. In this study, leaf extracts of A. aspera collected from two different geographical locations (Ciaat, Eritrea and Ukulinga, South Africa) were evaluated for antibacterial, antifungal, anthelmintic activities and the plant characterized for functional phenolic acids as well as protein binding capacity. The pathogens used in the tests were, two Gram-negative (Escherichia coli and Klebsiella pneumoniae), two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), a filamentus yeast-like fungus (Candida albicans) and a free-living nematode (Caenorhabditis elegans). The water and acetone extracts of the samples collected from Ciaat exhibited good antibacterial, antifungal and anthelmintic activity (MIC < 1 mg/ml) except the water extract against E. coli which showed moderate activity. In contrast, the extracts collected from Ukulinga exhibited moderate to weak activities except for the acetone (aq.) extracts which had good activity against some of the tested organisms. UHPLC-MS/MS revealed variation in the levels of some functional phenolic compounds, with rutin, chlorogenic acid and genistein not being detected in the extracts from Ukulinga. The variation was also observed in the protein binding capacity, which could offer a predictive wound healing model. All extracts from plant samples collected at Ciaat expressed significant dominant potency compared to similar extracts from Ukulinga.