Natural products - learning chemistry from plants

Endophytic fungi: A future prospect for breast cancer therapeutics and drug development

Globally, breast cancer is a primary contributor to cancer-related fatalities and illnesses among women. Consequently, there is a pressing need for safe and effective treatments for breast cancer. Bioactive compounds from endophytic fungi that live in symbiosis with medicinal plants have garnered significant interest in pharmaceutical research due to their extensive chemical composition and prospective medicinal attributes. This review underscores the potentiality of fungal endophytes as a promising resource for the development of innovative anticancer agents specifically tailored for breast cancer therapy. The diversity of endophytic fungi residing in medicinal plants, success stories of key endophytic bioactive metabolites tested against breast cancer and the current progress with regards to in vivo studies and clinical trials on endophytic fungal metabolites in breast cancer research forms the underlying theme of this article. A thorough compilation of putative anticancer compounds sourced from endophytic fungi that have demonstrated therapeutic potential against breast cancer, spanning the period from 1990 to 2022, has been presented. This review article also outlines the latest trends in endophyte-based drug discovery, including the use of artificial intelligence, machine learning, multi-omics approaches, and high-throughput strategies. The challenges and future prospects associated with fungal endophytes as substitutive sources for developing anticancer drugs targeting breast cancer are also being highlighted.

Medicinal plants meet modern biodiversity science

Plants have been an essential source of human medicine for millennia. In this review, we argue that a holistic, interdisciplinary approach to the study of medicinal plants that combines methods and insights from three key disciplines - evolutionary ecology, molecular biology/biochemistry, and ethnopharmacology - is poised to facilitate new breakthroughs in science, including pharmacological discoveries and rapid advancements in human health and well-being. Such interdisciplinary research leverages data and methods spanning space, time, and species associated with medicinal plant species evolution, ecology, genomics, and metabolomic trait diversity, all of which build heavily on traditional Indigenous knowledge. Such an interdisciplinary approach contrasts sharply with most well-funded and successful medicinal plant research during the last half-century, which, despite notable advancements, has greatly oversimplified the dynamic relationships between plants and humans, kept hidden the larger human narratives about these relationships, and overlooked potentially important research and discoveries into life-saving medicines. We suggest that medicinal plants and people should be viewed as partners whose relationship involves a complicated and poorly explored set of (socio-)ecological interactions including not only domestication but also commensalisms and mutualisms. In short, medicinal plant species are not just chemical factories for extraction and exploitation. Rather, they may be symbiotic partners that have shaped modern societies, improved human health, and extended human lifespans.

Impact of Phylogenetically Diverse Bacterial Endophytes of Bergenia pacumbis on Bergenin Production in the Plant Cell Suspension Cultures

Plant in vitro cultures are potential sources for secondary metabolites. However, low productivity is often a major drawback for industrial application. Elicitation is an important strategy to improve product formation in vitro. In this context, endophytes are of special interest as biotic elicitors due to their possible interaction with the metabolism of the host plant. A total of 128 bacterial endophytes were isolated from the medicinal plant Bergenia pacumbis and taxonomically classified using 16S rRNA gene sequencing. Five strains belonging to different genera were grown in lysogeny broth and tryptic soy broth medium and cells as well as spent media were used as elicitors in cell suspension cultures of B. pacumbis. Production of the main bioactive compound bergenin was enhanced 3-fold (964 µg/g) after treatment with cells of Moraxella sp. or spent tryptic soy broth medium of Micrococcus sp. These results indicate that elicitation of plant cell suspension cultures with endophytic bacteria is a promising strategy for enhancing the production of desired plant metabolites.

A Review on Medicinal Plants Having Anticancer Properties of Northeast India and Associated Endophytic Microbes and their Future in Medicinal Science

Human beings are affected by different diseases and suffer to different extents. Cancer is one of the major human disease and millions of people suffered from cancer and end their lives every year. Peoples are dependent on herbal medicines since prehistoric time especially from developing countries. It is very common to have different side effects of modern synthetic medicines; hence now-a-days importance of herbal medicines due to no or least side effects increases all parts of the world. But the major problems of using herbal medicines are that plants can produce very limited amount of medicinally important bioactive metabolites and they have very long growth periods. Therefore endophytes are the excellent alternative of plant derived metabolites. Endophytic microbes can synthesize exactly same type of metabolites as the plant produces. North East India is a treasure of plant resources; various types of medicinal plants are present in this region. Different types of indigenous tribes are inhabited in this region who used different plants in traditional system for treating various disease. But with increasing demand it is sometimes not sufficient to manage the demand of medicines, therefore for massive production endophytic study is crucial. In spite of having huge plant resources very limited endophytic studies are observed in this region. In this review, we studied different plants with their endophytes of NE India showing anticancer properties.

Production of bioactive plant secondary metabolites through in vitro technologies-status and outlook

Medicinal plants have been used by mankind since ancient times, and many bioactive plant secondary metabolites are applied nowadays both directly as drugs, and as raw materials for semi-synthetic modifications. However, the structural complexity often thwarts cost-efficient chemical synthesis, and the usually low content in the native plant necessitates the processing of large amounts of field-cultivated raw material. The biotechnological manufacturing of such compounds offers a number of advantages like predictable, stable, and year-round sustainable production, scalability, and easier extraction and purification. Plant cell and tissue culture represents one possible alternative to the extraction of phytochemicals from plant material. Although a broad commercialization of such processes has not yet occurred, ongoing research indicates that plant in vitro systems such as cell suspension cultures, organ cultures, and transgenic hairy roots hold a promising potential as sources for bioactive compounds. Progress in the areas of biosynthetic pathway elucidation and genetic manipulation has expanded the possibilities to utilize plant metabolic engineering and heterologous production in microorganisms. This review aims to summarize recent advances in the in vitro production of high-value plant secondary metabolites of medicinal importance.

Key points

• Bioactive plant secondary metabolites are important for current and future use in medicine

• In vitro production is a sustainable alternative to extraction from plants or costly chemical synthesis

• Current research addresses plant cell and tissue culture, metabolic engineering, and heterologous production

Fungal Endophytes as Efficient Sources of Plant-Derived Bioactive Compounds and Their Prospective Applications in Natural Product Drug Discovery: Insights, Avenues, and Challenges

Fungal endophytes are well-established sources of biologically active natural compounds with many producing pharmacologically valuable specific plant-derived products. This review details typical plant-derived medicinal compounds of several classes, including alkaloids, coumarins, flavonoids, glycosides, lignans, phenylpropanoids, quinones, saponins, terpenoids, and xanthones that are produced by endophytic fungi. This review covers the studies carried out since the first report of taxol biosynthesis by endophytic Taxomyces andreanae in 1993 up to mid-2020. The article also highlights the prospects of endophyte-dependent biosynthesis of such plant-derived pharmacologically active compounds and the bottlenecks in the commercialization of this novel approach in the area of drug discovery. After recent updates in the field of 'omics' and 'one strain many compounds' (OSMAC) approach, fungal endophytes have emerged as strong unconventional source of such prized products.

Co-feeding glucose with either gluconate or galacturonate during clostridial fermentations provides metabolic fine-tuning capabilities

Clostridium acetobutylicum ATCC 824 effectively utilizes a wide range of substrates to produce commodity chemicals. When grown on substrates of different oxidation states, the organism exhibits different recycling needs of reduced intracellular electron carrying co-factors. Ratios of substrates with different oxidation states were used to modulate the need to balance electron carriers and demonstrate fine-tuned control of metabolic output. Three different oxidized substrates were first fed singularly, then in different ratios to three different strains of Clostridium sp. Growth was most robust when fed glucose in exclusive fermentations. However, the use of the other two more oxidized substrates was strain-dependent in exclusive feeds. In glucose-galacturonate mixed fermentation, the main products (acetate and butyrate) were dependant on the ratios of the substrates. Exclusive fermentation on galacturonate was nearly homoacetic. Co-utilization of galacturonate and glucose was observed from the onset of fermentation in growth conditions using both substrates combined, with the proportion of galacturonate present dictating the amount of acetate produced. For all three strains, increasing galacturonate content (%) in a mixture of galacturonate and glucose from 0 to 50, and 100, resulted in a corresponding increase in the amount of acetate produced. For example, C. acetobutylicum increased from ~ 10 mM to ~ 17 mM, and then ~ 23 mM. No co-utilization was observed when galacturonate was replaced with gluconate in the two substrate co-feed.

Production of glutamate and stereospecific flavors, (S)-linalool and (+)-valencene, by Synechocystis sp. PCC6803

Cyanobacteria can grow photoautotrophically, producing a range of substances by absorbing sunlight and utilizing carbon dioxide, and can potentially be used as industrial microbes that have minimal sugar requirements. To evaluate this potential, we explored the possibility of l-glutamate production using the Synechocystis sp. PCC6803. The ybjL gene encoding the putative l-glutamate exporter from Escherichia coli was introduced, and l-glutamate production reached 2.3 g/L in 143 h (34°C, 100 μmol m^-2 s^-1). Then, we attempted to produce two flavor substances, (S)-linalool, a monoterpene alcohol, and the sesquiterpene (+)-valencene. The Synechocystis sp. PCC6803 strain in which the linalool synthase gene (LINS) from Actinidia arguta (AaLINS) was expressed under control of the tac promoter (GT0846K-P_tac-AaLINS) produced 11.4 mg/L (S)-linalool in 160 h (30°C, 50 μmol m^-2 s^-1). The strain in which AaLINS2 and the mutated farnesyl diphosphate synthase gene ispA∗ (S80F) from E. coli (GT0846K-P_psbA2-AaLINS-ispA∗) were expressed from the P_psbA2 promoter accumulated 11.6 mg/L (S)-linalool in 160 h. Genome analysis revealed that both strains had mutations in slr1270, suggesting that loss of Slr1270 function was necessary for high linalool accumulation. For sesquiterpene production, the valencene synthase gene from Callitropsis nootkatensis and the fernesyl diphosphate synthase (ispA) gene from E. coli were introduced, and the resultant strain produced 9.6 mg/L of (+)-valencene in 166 h (30°C, 50 μmol m^-2 s^-1). This study highlights the production efficiency of engineered cyanobacteria, providing insight into potential industrial applications.

Evaluation of plant sources for antiinfective lead compound discovery by correlating phylogenetic, spatial, and bioactivity data

Antibiotic resistance and viral diseases are rising around the world and are becoming major threats to global health, food security, and development. One measure that has been suggested to mitigate this crisis is the development of new antibiotics. Here, we provide a comprehensive evaluation of the phylogenetic and biogeographic patterns of antiinfective compounds from seed plants in one of the most species-rich regions on Earth and identify clades with naturally occurring substances potentially suitable for the development of new pharmaceutical compounds. Specifically, we combine taxonomic and phylogenetic data for >7,500 seed plant species from the flora of Java with >16,500 secondary metabolites and 6,255 georeferenced occurrence records to 1) identify clades in the phylogeny that are characterized by either an overrepresentation ("hot clades") or an underrepresentation ("cold clades") of antiinfective compounds and 2) assess the spatial patterns of plants with antiinfective compounds relative to total plant diversity across the region. Across the flora of Java, we identify 26 "hot clades" with plant species providing a high probability of finding antibiotic constituents. In addition, 24 "cold clades" constitute lineages with low numbers of reported activities but which have the potential to yield novel compounds. Spatial patterns of plant species and metabolite diversity are strongly correlated across Java, indicating that regions of highest species diversity afford the highest potential to discover novel natural products. Our results indicate that the combination of phylogenetic, spatial, and phytochemical information is a useful tool to guide the selection of taxa for efforts aimed at lead compound discovery.

Novel biotechnological glucosylation of high-impact aroma chemicals, 3(2H)- and 2(5H)-furanones

Glucosyltransferases are versatile biocatalysts to chemically modify small molecules and thus enhance their water solubility and structural stability. Although the genomes of all organisms harbor a multitude of glucosyltransferase genes, their functional characterization is hampered by the lack of high-throughput in-vivo systems to rapidly test the versatility of the encoded proteins. We have developed and applied a high-throughput whole cell biotransformation system to screen a plant glucosyltransferase library. As proof of principle, we identified 25, 24, 15, and 18 biocatalysts transferring D-glucose to sotolone, maple furanone, furaneol and homofuraneol, four highly appreciated flavor compounds, respectively. Although these 3(2H)- and 2(5H)-furanones have extremely low odor thresholds their glucosides were odorless. Upscaling of the biotechnological process yielded titers of 5.3 and 7.2 g/L for the new to nature β-D-glucopyranosides of sotolone and maple furanone, respectively. Consequently, plant glucosyltransferase show stunning catalytic activities, which enable the economical production of novel and unexplored chemicals with exciting new functionalities by whole-cell biotransformation.

Combinatorial biosynthesis of small molecules in plants: Engineering strategies and tools

Biosynthetic capacity of plants, rooted in a near inexhaustible supply of photosynthetic energy and founded upon an intricate matrix of metabolic networks, makes them versatile chemists producing myriad specialized compounds. Along with tremendous success in elucidation of several plant biosynthetic routes, their reestablishment in heterologous hosts has been a hallmark of recent bioengineering endeavors. However, current efforts in the field are, in the main, aimed at grafting the pathways to fermentable recipient organisms, like bacteria or yeast. Conversely, while harboring orthologous metabolic trails, select plant species now emerge as viable vehicles for mobilization and engineering of complex biosynthetic pathways. Their distinctive features, like intricate cell compartmentalization and formation of specialized production and storage structures on tissue and organ level, make plants an especially promising chassis for the manufacture of considerable amounts of high-value natural small molecules. Inspired by the fundamental tenets of synthetic biology, capitalizing on the versatility of the transient plant transformation system, and drawing on the unique compartmentation of plant cells, we explore combinatorial approaches affording production of natural and new-to-nature, bespoke chemicals of potential importance. Here, we focus on the transient engineering of P450 monooxygenases, alone or in concert with other orthogonal catalysts, like tryptophan halogenases.

D2O Labeling to Measure Active Biosynthesis of Natural Products in Medicinal Plants

Plant natural products have served as a prominent source of medicines throughout human history, and are still used today as clinically-approved pharmaceuticals. However, many medicinal plants that produce useful compounds are slow-growing or recalcitrant to cultivation, making it difficult to investigate the underlying genetic/enzymatic machinery responsible for biosynthesis. To better understand the metabolism of bioactive natural products in slow-growing medicinal plants, we used D2O labeling and LC-MS-based metabolomics to explore the biosynthesis of medically-relevant alkaloids in three plant species. Our results provide evidence for sites of active biosynthesis for these alkaloids, and demonstrate that D2O labeling can be used as a general method to determine sites of active secondary metabolism over relatively short time scales. We anticipate that these results will facilitate discovery of complete metabolic pathways for plant natural products of medicinal importance, especially for approaches that rely upon transcriptomics and knowledge of active metabolism to identify biosynthetic enzymes.

Natural Products Extraction of the Future—Sustainable Manufacturing Solutions for Societal Needs

The production of plant-based extracts is significantly influenced by traditional techniques and the natural variability of feedstock. For that reason, the discussion of innovative approaches to improve the manufacturing of established products and the development of new products within the regulatory framework is essential to adapt to shifting quality standards. This perspective of members of the DECHEMA/ProcessNet working group on plant-based extracts outlines extraction business models and the regulatory framework regarding the extraction of traditional herbal medicines as complex extracts. Consequently, modern approaches to innovative process design methods like QbD (Quality by Design) and quality control in the form of PAT (Process Analytical Technology) are necessary. Further, the benefit of standardized laboratory equipment combined with physico-chemical predictive process modelling and innovative modular, flexible batch or continuous manufacturing technologies which are fully automated by advanced process control methods are described. A significant reduction of the cost of goods, i.e., by a factor of 4–10, and decreased investments of about 1–5 mil. € show the potential for new products which are in line with market requirements.

Engineering of new-to-nature halogenated indigo precursors in plants

Plants are versatile chemists producing a tremendous variety of specialized compounds. Here, we describe the engineering of entirely novel metabolic pathways in planta enabling generation of halogenated indigo precursors as non-natural plant products. Indican (indolyl-β-D-glucopyranoside) is a secondary metabolite characteristic of a number of dyers plants. Its deglucosylation and subsequent oxidative dimerization leads to the blue dye, indigo. Halogenated indican derivatives are commonly used as detection reagents in histochemical and molecular biology applications; their production, however, relies largely on chemical synthesis. To attain the de novo biosynthesis in a plant-based system devoid of indican, we employed a sequence of enzymes from diverse sources, including three microbial tryptophan halogenases substituting the amino acid at either C5, C6, or C7 of the indole moiety. Subsequent processing of the halotryptophan by bacterial tryptophanase TnaA in concert with a mutant of the human cytochrome P450 monooxygenase 2A6 and glycosylation of the resulting indoxyl derivatives by an endogenous tobacco glucosyltransferase yielded corresponding haloindican variants in transiently transformed Nicotiana benthamiana plants. Accumulation levels were highest when the 5-halogenase PyrH was utilized, reaching 0.93 ± 0.089 mg/g dry weight of 5-chloroindican. The identity of the latter was unambiguously confirmed by NMR analysis. Moreover, our combinatorial approach, facilitated by the modular assembly capabilities of the GoldenBraid cloning system and inspired by the unique compartmentation of plant cells, afforded testing a number of alternative subcellular localizations for pathway design. In consequence, chloroplasts were validated as functional biosynthetic venues for haloindican, with the requisite reducing augmentation of the halogenases as well as the cytochrome P450 monooxygenase fulfilled by catalytic systems native to the organelle. Thus, our study puts forward a viable alternative production platform for halogenated fine chemicals, eschewing reliance on fossil fuel resources and toxic chemicals. We further contend that in planta generation of halogenated indigoid precursors previously unknown to nature offers an extended view on and, indeed, pushes forward the established frontiers of biosynthetic capacity of plants.

Recent advances and effective strategies in the discovery and applications of natural products

Natural products are the most representative form of conventional therapy as compared to any other traditional or alternative medicine systems.

Synthetic biology strategies toward heterologous phytochemical production

This review summarizes the recent progress in heterologous phytochemical biosynthetic pathway reconstitution in plant, bacteria, and yeast, with a focus on the synthetic biology strategies applied in these engineering efforts.

Recent Advances in the Recombinant Biosynthesis of Polyphenols

Plants are the source of various natural compounds with pharmaceutical and nutraceutical importance which have shown numerous health benefits with relatively fewer side effects. However, extraction of these compounds from native producers cannot meet the ever-increasing demands of the growing population due to, among other things, the limited production of the active compound(s). Their production depends upon the metabolic demands of the plant and is also subjected to environmental conditions, abundance of crop species and seasonal variations. Moreover, their extraction from plants requires complex downstream processing and can also lead to the extinction of many useful plant varieties. Microbial engineering is one of the alternative approaches which can meet the global demand for natural products in an eco-friendly manner. Metabolic engineering of microbes or pathway reconstruction using synthetic biology tools and novel enzymes lead to the generation of a diversity of compounds (like flavonoids, stilbenes, anthocyanins etc.) and their natural and non-natural derivatives. Strain and pathway optimization, pathway regulation and tolerance engineering have produced microbial cell factories into which the metabolic pathway of plants can be introduced for the production of compounds of interest on an industrial scale in an economical and eco-friendly way. While microbial production of phytochemicals needs to further increase product titer if it is ever to become a commercial success. The present review covers the advancements made for the improvement of microbial cell factories in order to increase the product titer of recombinant polyphenolic compounds.

Production of anthocyanins in metabolically engineered microorganisms: Current status and perspectives

Microbial production of plant-derived natural products by engineered microorganisms has achieved great success thanks to large extend to metabolic engineering and synthetic biology. Anthocyanins, the water-soluble colored pigments found in terrestrial plants that are responsible for the red, blue and purple coloration of many flowers and fruits, are extensively used in food and cosmetics industry; however, their current supply heavily relies on complex extraction from plant-based materials. A promising alternative is their sustainable production in metabolically engineered microbes. Here, we review the recent progress on anthocyanin biosynthesis in engineered bacteria, with a special focus on the systematic engineering modifications such as selection and engineering of biosynthetic enzymes, engineering of transportation, regulation of UDP-glucose supply, as well as process optimization. These promising engineering strategies will facilitate successful microbial production of anthocyanins in industry in the near future.

Synthetic and natural Peroxisome Proliferator-Activated Receptor (PPAR) agonists as candidates for the therapy of the metabolic syndrome

INTRODUCTION

Peroxisome proliferator-activated receptors (PPARs) are the molecular targets of hypolipidemic and insulin-sensitizing drugs and implicated in a multitude of processes that fine-tune the functions of all organs in vertebrates. As transcription factors they sense endogenous and exogenous lipid signaling molecules and convert these signals into intricate gene responses that impact health and disease. The PPARs act as modulators of cellular, organ, and systemic processes, such as lipid and carbohydrate metabolism, making them valuable for understanding body homeostasis influenced by nutrition and exercise. Areas covered: This review concentrates on synthetic and natural PPAR ligands and how they have helped reveal many aspects of the transcriptional control of complex processes important in health. Expert opinion: The three PPARs have complementary roles in the fine-tuning of most fundamental body functions, especially energy metabolism. Understanding their inter-relatedness using ligands that simultaneously modulate the activity of more than one of these receptors is a major goal. This approach may provide essential knowledge for the development of dual or pan-PPAR agonists or antagonists as potential new health-promoting agents and for nutritional approaches to prevent metabolic diseases.

Recombinant flavin-dependent halogenases are functional in tobacco chloroplasts without co-expression of flavin reductase genes

Halogenation of natural compounds in planta is rare. Herein, a successful engineering of tryptophan 6-halogenation into the plant context by heterologous expression of the Streptomyces toxytricini Stth gene and localization of its enzymatic product in various tobacco cell compartments is described. When co-expressed with the flavin reductase rebF from Lechevalieria aerocolonigenes, Stth efficiently produced chlorinated tryptophan in the cytosol. Further, supplementation of KBr yielded the brominated metabolite. More strikingly, targeting of the protein to the chloroplasts enabled effective halogenation of tryptophan even in absence of the partner reductase, providing crucial evidence for sufficient, organelle-specific supply of the FADH2 cofactor to drive halogen integration. Incorporation of an alternative enzyme, the 7-halogenase RebH from L. aerocolonigenes, into the metabolic set-up resulted in the formation of 6,7-dichlorotryptophan. Finally, expression of tryptophan decarboxylase (tdc) in concert with stth led to the generation of 6-chlorotryptamine, a new-to-nature precursor of monoterpenoid indole alkaloids. In sum, the report highlights the tremendous application potential of plants as a unique chassis for the engineering of rare and valuable halogenated natural products, with chloroplasts as the cache of reduction equivalents driving metabolic reactions.

Huangkui capsule, an extract from Abelmoschus manihot (L.) medic, improves diabetic nephropathy via activating peroxisome proliferator-activated receptor (PPAR)-α/γ and attenuating endoplasmic reticulum stress in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Abelmoschus manihot (L.) medic (AM) is a natural medicinal plant used for the treatment of chronic kidney disease (CKD) in China. Huangkui capsule (HKC), an extract from AM, has been proved clinically effective in improving renal inflammation and glomerular injury in CKD. However, the mechanisms of HKC are still not fully understood.

AIM OF THE STUDY

Peroxisome proliferator-activated receptor (PPAR)-α/γ dual agonists have the potential to be used as therapeutic agents for the treatment of type 2 diabetes and diabetic nephropathy (DN). This study evaluated the function of Huangkui capsule (HKC), an extract from Abelmoschus manihot (L.) medic (AM), as a dual agonist for PPARα/γ and investigated its anti-DN effects in a DN rat model.

MATERIALS AND METHODS

ChIP and reporter gene assays were performed and the expression of PPARα/γ target genes was monitored to examine the ability of HKC to activate PPARα/γ. DN was induced in male Sprague-Dawley rats via unilateral nephrectomy and intraperitoneal injection of streptozotocin. HKC was administered to the diabetic nephropathy rats at three different doses: high dose HKC (300mg/kg/d); middle dose HKC (175mg/kg/d); and low dose HKC (75mg/kg/d). Irbesartan (4mg/kg/d body weight) was used as a positive control. Following 12 weeks' treatment, we measured general status, renal morphological appearance, proteinuria, blood biochemical parameters, and glomerular morphological changes. The expression of collagen IV, TGFβ, TNFα and IL-6 in renal tissue was evaluated. Endoplasmic reticulum (ER) stress in renal tissue was also analyzed.

RESULTS

HKC enhanced the transcriptional activity of PPARα and PPARγ in cultured cells, livers and kidneys of DN rats, and it reduced serum triglyceride and cholesterol levels and fat in livers of DN rats. Furthermore, HKC reduced the expressions of inflammatory genes in kidneys of DN rats. Strikingly, HKC reduced ER stress and c-Jun NH2-terminal kinase activation in the liver and kidney of DN rats and subsequently improved renal injury.

CONCLUSIONS

Our results show that HKC improved lipid metabolic disorders by activating PPARα/γ and attenuating ER stress. HKC could dose-dependently ameliorate renal inflammation and glomerular injury in DN rats. These results suggest that HKC has potential as an anti-DN agent for the treatment of DN in humans.

A novel cinnamyl alcohol dehydrogenase (CAD)-like reductase contributes to the structural diversity of monoterpenoid indole alkaloids in Rauvolfia

Based on findings described herein, we contend that the reduction of vomilenine en route to antiarrhythmic ajmaline in planta might proceed via an alternative, novel sequence of biosynthetic steps. In the genus Rauvolfia, monoterpenoid indole alkaloids (MIAs) are formed via complex biosynthetic sequences. Despite the wealth of information about the biochemistry and molecular genetics underlying these processes, many reaction steps involving oxygenases and oxidoreductases are still elusive. Here, we describe molecular cloning and characterization of three cinnamyl alcohol dehydrogenase (CAD)-like reductases from Rauvolfia serpentina cell culture and R. tetraphylla roots. Functional analysis of the recombinant proteins, with a set of MIAs as potential substrates, led to identification of one of the enzymes as a CAD, putatively involved in lignin formation. The two remaining reductases comprise isoenzymes derived from orthologous genes of the investigated alternative Rauvolfia species. Their catalytic activity consists of specific conversion of vomilenine to 19,20-dihydrovomilenine, thus proving their exclusive involvement in MIA biosynthesis. The obtained data suggest the existence of a previously unknown bypass in the biosynthetic route to ajmaline further expanding structural diversity within the MIA family of specialized plant metabolites.

Discovery and resupply of pharmacologically active plant-derived natural products: A review

Medicinal plants have historically proven their value as a source of molecules with therapeutic potential, and nowadays still represent an important pool for the identification of novel drug leads. In the past decades, pharmaceutical industry focused mainly on libraries of synthetic compounds as drug discovery source. They are comparably easy to produce and resupply, and demonstrate good compatibility with established high throughput screening (HTS) platforms. However, at the same time there has been a declining trend in the number of new drugs reaching the market, raising renewed scientific interest in drug discovery from natural sources, despite of its known challenges. In this survey, a brief outline of historical development is provided together with a comprehensive overview of used approaches and recent developments relevant to plant-derived natural product drug discovery. Associated challenges and major strengths of natural product-based drug discovery are critically discussed. A snapshot of the advanced plant-derived natural products that are currently in actively recruiting clinical trials is also presented. Importantly, the transition of a natural compound from a "screening hit" through a "drug lead" to a "marketed drug" is associated with increasingly challenging demands for compound amount, which often cannot be met by re-isolation from the respective plant sources. In this regard, existing alternatives for resupply are also discussed, including different biotechnology approaches and total organic synthesis. While the intrinsic complexity of natural product-based drug discovery necessitates highly integrated interdisciplinary approaches, the reviewed scientific developments, recent technological advances, and research trends clearly indicate that natural products will be among the most important sources of new drugs also in the future.

Phytochemical, antioxidant and antidiabetic evaluation of eight Bauhinia L. species from Egypt using UHPLC-PDA-qTOF-MS and chemometrics

Bauhinia L. (Fabaceae) comprises ca. 300-350 plant species, many of which are traditionally used in folk medicine for their antidiabetic, antioxidant and anti-inflammatory effects. Bauhinia s.l. recently has been subdivided into 9 genera based on phylogenetic data: Bauhinia s.str., Barklya, Brenierea, Gigasiphon, Lysiphyllum, Phanera, Piliostigma, Schnella (American Phanera) and Tylosema. The aerial parts of 8 species corresponding to 5 genera were analyzed: Bauhinia forficata, Bauhinia variegata, B. variegata var. candida, Bauhinia galpinii, Schnella glabra, Piliostigma racemosa, Phanera vahlii and Lysiphyllum hookeri. Leaves and shoots were subjected to metabolite profiling via UHPLC-PDA-qTOF-MS coupled to multivariate data analyzes to identify compound compositional differences. A total of 90 metabolites were identified including polyphenols and fatty acids; flavonoid conjugates accounted for most of the metabolite variation observed. This study provides a comprehensive map of polyphenol composition in Bauhinia and phytochemical species aggregations are consistent with recent Bauhinia genus taxonomic relationship derived from phylogenetic studies. DPPH radical scavenging and α-glucosidase inhibitory assays were also performed to assess selected aspects of the antioxidant and antidiabetic potential for the examined species with respect to metabolite profiles.

Editorial: Biotechnology Journal's diverse coverage of biotechnology

This issue of Biotechnology Journal is a regular issue edited by Prof. Michael Wink. The issue covers all the major focus areas of the journal, including medical biotechnology, synthetic biology, and novel biotechnological methods.