Piperine production by endophytic fungus Periconia sp. Isolated from Piper longum L

Formation of Biogenic Manganese Oxide Nodules on Hyphae of a New Fungal Isolate of Periconia That Immobilizes Aqueous Copper

Mn(II)-oxidizing microorganisms are considered to play significant roles in the natural geochemical cycles of Mn and other heavy metals because the insoluble biogenic Mn oxides (BMOs) that are produced by these microorganisms adsorb other dissolved heavy metals and immobilize them as precipitates. In the present study, a new Mn(II)-oxidizing fungal strain belonging to the ascomycete genus Periconia, a well-studied plant-associating fungal genus with Mn(II)-oxidizing activity that has not yet been exami-ned in detail, was isolated from natural groundwater outflow sediment. This isolate, named strain TS-2, was confirmed to oxidize dissolved Mn(II) and produce insoluble BMOs that formed characteristic, separately-located nodules on their hyphae while leaving major areas of the hyphae free from encrustation. These BMO nodules also adsorbed and immobilized dissolved Cu(II), a model analyte of heavy metals, as evidenced by elemental mapping ana-lyses of fungal hyphae-BMO assemblages using a scanning electron microscope with energy-dispersive X-ray spectroscopy (SEM-EDX). Analyses of functional genes within the whole genome of strain TS-2 further revealed the presence of multiple genes predicted to encode laccases/multicopper oxidases that were potentially responsible for Mn(II) oxidation by this strain. The formation of BMO nodules may have functioned to prevent the complete encrustation of fungal hyphae, thereby enabling the control of heavy metal concentrations in their local microenvironments while maintaining hyphal functionality. The present results will expand our knowledge of the physiological and morphological traits of Mn(II)-oxidizing Periconia, which may affect the natural cycle of heavy metals through their immobilization.

Antibacterial and immunological properties of piperine evidenced by preclinical studies: a systematic review

Aim: To review in vitro, in vivo, and in silico studies examining the antibacterial and immunomodulatory properties of piperine (PPN). Methods: This systematic review followed PRISMA guidelines, and five databases were searched. Results: A total of 40 articles were included in this study. Six aspects of PPN activity were identified, including antibacterial spectrum, association with antibiotics, efflux pump inhibition, biofilm effects, protein target binding, and modulation of immune functions/virulence factors. Most studies focused on Mycobacterium spp. and Staphylococcus aureus. Cell lineages and in vivo models were employed to study PPN antibacterial effects. Conclusion: We highlight PPN as a potential adjuvant in the treatment of bacterial infections. PPN possesses several antibacterial properties that need further exploration to determine the mechanisms behind its pharmacological activity.

Genome sequence and annotation of Periconia digitata a hopeful biocontrol agent of phytopathogenic oomycetes

The Periconia fungal genus belongs to the phylum Ascomycota, order Pleosporales, family Periconiaceae. Periconia are found in many habitats, but little is known about their ecology. Several species from this genus produce bioactive molecules. Periconia digitata extracts were shown to be deadly active against the pine wilt nematode. Furthermore, P. digitata was shown to inhibit the plant pathogenic oomycete Phytophthora parasitica. Because P. digitata has great potential as a biocontrol agent and high quality genomic resources are still lacking in the Periconiaceae family, we generated long-read genomic data for P. digitata. Using PacBio Hifi sequencing technology, we obtained a highly-contiguous genome assembled in 13 chromosomes and totaling ca. 39 Mb. In addition, we produced a reference transcriptome, based on 12 different culture conditions, and proteomic data to support the genome annotation. Besides representing a new reference genome within the Periconiaceae, this work will contribute to our better understanding of the Eukaryotic tree of life and opens new possibilities in terms of biotechnological applications.

Microbial Endophytes: Emerging Trends and Biotechnological Applications

A plethora of knowledge on the role of endophytic microorganisms has been reported in recent years. The cooperative chemistry between the endophytes and the internal host tissue has turned them into a crucial aid for biotechnological applications. Microbial endophytes are ubiquitous among most plant species on earth and contribute to the benefit of host plants by generating a wide range of metabolites that provide the plant with survival value. Endophytes can either directly stimulate plant growth by producing phytohormones or indirectly stimulate plant growth by increasing the availability of soil nutrients to plants. Endophytes may also help suppress diseases in plants directly by neutralizing environmental toxic elements, and by inhibiting plant pathogens by antagonistic action, or indirectly by stimulating induced plant systemic resistance. Several natural compounds produced by endophytes as secondary metabolites are beneficial to both plants and humans. This is why endophytes are regarded as a significant source of novel natural products of value in modern medicine, agriculture, and industry. Endophytes are known for producing pigments, bioactive compounds, and industrially important enzymes, like glucanase, amylase, laccase, etc. Some endophytes can also produce nanoparticles that potentially have numerous applications in a variety of fields. They also play an important role in biodegradation and bioremediation, both of which are beneficial to the environment and ecology. In this review, we highlighted potential biotechnological applications of endophytic microbes, as well as their diverse importance in plant growth and public health.

Plants as the Extended Phenotype of Endophytes-The Actual Source of Bioactive Compounds

For thousands of years, plants have been used for their medicinal properties. The industrial production of plant-beneficial compounds is facing many drawbacks, such as seasonal dependence and troublesome extraction and purification processes, which have led to many species being on the edge of extinction. As the demand for compounds applicable to, e.g., cancer treatment, is still growing, there is a need to develop sustainable production processes. The industrial potential of the endophytic microorganisms residing within plant tissues is undeniable, as they are often able to produce, in vitro, similar to or even the same compounds as their hosts. The peculiar conditions of the endophytic lifestyle raise questions about the molecular background of the biosynthesis of these bioactive compounds in planta, and the actual producer, whether it is the plant itself or its residents. Extending this knowledge is crucial to overcoming the current limitations in the implementation of endophytes for larger-scale production. In this review, we focus on the possible routes of the synthesis of host-specific compounds in planta by their endophytes.

Current trends in natural products for the treatment and management of dementia: Computational to clinical studies

The number of preclinical and clinical studies evaluating natural products-based management of dementia has gradually increased, with an exponential rise in 2020 and 2021. Keeping this in mind, we examined current trends from 2016 to 2021 in order to assess the growth potential of natural products in the treatment of dementia. Publicly available literature was collected from various databases like PubMed and Google Scholar. Oxidative stress-related targets, NF-κB pathway, anti-tau aggregation, anti-AChE, and A-β aggregation were found to be common targets and pathways. A retrospective analysis of 33 antidementia natural compounds identified 125 sustainable resources distributed among 65 families, 39 orders, and 7 classes. We found that families such as Berberidaceae, Zingiberaceae, and Fabaceae, as well as orders such as Lamiales, Sapindales, and Myrtales, appear to be important and should be researched further for antidementia compounds. Moreover, some natural products, such as quercetin, curcumin, icariside II, berberine, and resveratrol, have a wide range of applications. Clinical studies and patents support the importance of dietary supplements and natural products, which we will also discuss. Finally, we conclude with the broad scope, future challenges, and opportunities for field researchers.

An insight into endophytic antimicrobial compounds: an updated analysis

Resistance in micro-organisms against antimicrobial compounds is an emerging phenomenon in the modern era as compared to the traditional world which brings new challenges to discover novel antimicrobial compounds from different available sources, such as, medicinal plants, various micro-organisms, like, bacteria, fungi, algae, actinomycetes, and endophytes. Endophytes reside inside the plants without exerting any harmful impact on the host plant along with providing ample of benefits. In addition, they are capable of producing diverse antimicrobial compounds similar to their host, allowing them to serve as useful micro-organism for a range of therapeutic purposes. In recent years, a large number of studies on the antimicrobial properties of endophytic fungi have been carried out globally. These antimicrobials have been used to treat various bacterial, fungal, and viral infections in humans. In this review, the potential of fungal endophytes to produce diverse antimicrobial compounds along with their various benefits to their host have been focused on. In addition, classification systems of endophytic fungi as well as the need for antimicrobial production with genetic involvement and some of the vital novel antimicrobial compounds of endophytic origin can further be utilized in the pharmaceutical industries for various formulations along with the role of nanoparticles as antimicrobial agents have been highlighted.

An Assessment of the In Vitro Models and Clinical Trials Related to the Antimicrobial Activities of Phytochemicals

An increased number antibiotic-resistant bacteria have emerged with the rise in antibiotic use worldwide. As such, there has been a growing interest in investigating novel antibiotics against antibiotic-resistant bacteria. Due to the extensive history of using plants for medicinal purposes, scientists and medical professionals have turned to plants as potential alternatives to common antibiotic treatments. Unlike other antibiotics in use, plant-based antibiotics have the innate ability to eliminate a broad spectrum of microorganisms through phytochemical defenses, including compounds such as alkaloids, organosulfur compounds, phenols, coumarins, and terpenes. In recent years, these antimicrobial compounds have been refined through extraction methods and tested against antibiotic-resistant strains of Gram-negative and Gram-positive bacteria. The results of the experiments demonstrated that plant extracts successfully inhibited bacteria independently or in combination with other antimicrobial products. In this review, we examine the use of plant-based antibiotics for their utilization against antibiotic-resistant bacterial infections. In addition, we examine recent clinical trials utilizing phytochemicals for the treatment of several microbial infections.

Effect of the application of vermicompost and millicompost humic acids about the soybean microbiome under water restriction conditions

Humic substances (HSs) are constituent fractions of organic matter and are highly complex and biologically active. These substances include humic acids (HA), fulvic acids (FA), and humin. HS are known to stimulate the root system and plant growth and to mitigate stress damage, including hydric stress. Humic acids have already been reported to increase microbial growth, affecting their beneficial effect on plants. However, there is scarce information on whether HA from vermicompost and millicompost, along with Bradyrhizobium, improves the tolerance of soybean to water restriction. This study aimed to evaluate the responses of soybean plants to the application of vermicompost HA (HA-V) and millicompost (HA-M) along with Bradyrhizobium sp. under water restriction. The experiment was carried out in a greenhouse, and the treatments received Bradyrhizobium sp. inoculation with or without the application of HA from vermicompost and millicompost with or without water restriction. The results showed that HA provided greater soybean growth and nodulation than the control. The application of HA-M stimulated an increase in the richness of bacterial species in roots compared to the other treatments. After the application of water stress, the difference between the treatments disappeared. Microbial taxa were differentially abundant in plants, with the fungal fraction most affected by HA application in stressed roots. HA-V appears to be more prominent in inducing taxa under stress conditions. Although the results showed slight differences between HA from vermicompost and millicompost regarding plant growth, both humic acids promoted an increase in plant development compared to the control.

Metabolites of medicine food homology-derived endophytic fungi and their activities

Medicine food homology (MFH) substances not only provide essential nutrients as food but also have corresponding factors that can prevent and help treat nutritional imbalances, chronic disease, and other related issues. Endophytic fungi associated with plants have potential for use in drug discovery and food therapy. However, the endophytic fungal metabolites from MFH plants and their effects have been overlooked. Therefore, this review focuses on the various biological activities of 108 new metabolites isolated from 53 MFH-derived endophytic fungi. The paper explores the potential nutritional and medicinal value of metabolites of MFH-derived endophytic fungi for food and medical applications. This research is important for the future development of effective, safe, and nontoxic therapeutic nutraceuticals for the prevention and treatment of human diseases.

Water Extract of Piper longum Linn Ameliorates Ovariectomy-Induced Bone Loss by Inhibiting Osteoclast Differentiation

Piper longum linn has traditionally been used for the treatment of respiratory and gastrointestinal disorders in India. Although various pharmacological effects of P. longum have been studied, its effects on bone have not been clearly elucidated. Therefore, this study examined the inhibitory effect of the water extract of P. longum Linn (WEPL) on osteoclast differentiation. WEPL directly affected the osteoclast precursors and suppressed osteoclast differentiation in vitro. In addition, the expression levels of c-Fos and nuclear factor of activated T cells 1, a critical transcription factor for osteoclastogenesis, were significantly downregulated by WEPL via the suppression of the receptor activator of nuclear factor (NF)-κB ligand-induced mitogen-activated protein kinase and NF-κB signaling pathways. Consistent with the in vitro results, oral administration of WEPL (100 and 300 mpk) to ovariectomized mice for six weeks relieved the OVX-induced bone loss. We also identified phytochemicals in WEPL that are reported to exert inhibitory effects on osteoclastogenesis and/or bone loss. Collectively, the findings of our study indicate that WEPL has an anti-osteoporotic effect on OVX-induced bone loss by diminishing osteoclast differentiation, suggesting that it may be useful to treat several bone diseases caused by excessive bone resorption.

Metabolomic Insights Into Endophyte-Derived Bioactive Compounds

Among the various plant-associated microbiota, endophytes (the microbial communities inhabiting plant endosphere without causing disease symptoms) exhibit the most intimate and specific association with host plants. Endophytic microbes influence various aspects of plant responses (such as increasing availability of nutrients, tolerance against biotic and abiotic stresses, etc.) by modulating the primary and secondary metabolism of the host. Besides, endophytic microbes produce a diverse array of bioactive compounds, which have potential applications in the pharmaceutical, food, and cosmetic industries. Further, there is sufficient evidence for endophyte-derived plant metabolites, which could be pursued as alternative sources of commercially important plant metabolites. The field of bioprospecting, the discovery of novel chemistries, and endophyte-mediated production of plant metabolites have witnessed a boom with the advent of omics technologies (especially metabolomics) in endophyte research. The high throughput study of small metabolites at a particular timepoint or tissue forms the core of metabolomics. Being downstream to transcriptome and proteome, the metabolome provides the most direct reflection of the phenotype of an organism. The contribution of plant and microbial metabolomics for answering fundamental questions of plant-endophyte interaction, such as the effect of endophyte inoculation on plant metabolome, composition of metabolites on the impact of environmental stressors (biotic and abiotic), etc., have also been discussed.

Endophytic Fungi: Key Insights, Emerging Prospects, and Challenges in Natural Product Drug Discovery

Plant-associated endophytes define an important symbiotic association in nature and are established bio-reservoirs of plant-derived natural products. Endophytes colonize the internal tissues of a plant without causing any disease symptoms or apparent changes. Recently, there has been a growing interest in endophytes because of their beneficial effects on the production of novel metabolites of pharmacological significance. Studies have highlighted the socio-economic implications of endophytic fungi in agriculture, medicine, and the environment, with considerable success. Endophytic fungi-mediated biosynthesis of well-known metabolites includes taxol from Taxomyces andreanae, azadirachtin A and B from Eupenicillium parvum, vincristine from Fusarium oxysporum, and quinine from Phomopsis sp. The discovery of the billion-dollar anticancer drug taxol was a landmark in endophyte biology/research and established new paradigms for the metabolic potential of plant-associated endophytes. In addition, endophytic fungi have emerged as potential prolific producers of antimicrobials, antiseptics, and antibiotics of plant origin. Although extensively studied as a “production platform” of novel pharmacological metabolites, the molecular mechanisms of plant–endophyte dynamics remain less understood/explored for their efficient utilization in drug discovery. The emerging trends in endophytic fungi-mediated biosynthesis of novel bioactive metabolites, success stories of key pharmacological metabolites, strategies to overcome the existing challenges in endophyte biology, and future direction in endophytic fungi-based drug discovery forms the underlying theme of this article.

Fungal Communities in the Native New Zealand Medicinal Plant Pseudowintera colorata (Horopito) Are Determined by Plant Organ Type and Host Maturity with Key Members Promoting Plant Growth

The plant Pseudowintera colorata is well known for its antimicrobial and medicinal properties and is endemic to New Zealand. Using PCR-Denaturing gradient gel electrophoresis (DGGE), we investigated the factors influencing the composition of endophytic fungal communities in P. colorata from ten distinct sites across New Zealand. Our results showed that plant organs of P. colorata influenced the diversity and richness of endophytic fungi (PERMANOVA, p < 0.05). In addition, plant maturity and its interactions revealed that endophytic fungal communities formed discrete clusters in leaves, stems, and roots of mature and immature P. colorata plants (PERMANOVA; p = 0.002, p = 0.001 and p = 0.039, respectively). For identifying isolates with biocontrol potential, dual culture tests were set up against four different phytopathogenic fungi. Isolates with high activity (zone of inhibition > 10 mm) were sequenced and identified as Trichoderma harzianum, Pezicula neosporulosa, Fusariumtricinctum, Metarhizium sp., and Chaetomium sp. Applying selected endophytic fungi (n = 7) as soil drenchers significantly increased the growth of P. colorata seedlings and produced more internodes. Seedling shoots treated with Trichoderma sp. PRY2BA21 were 2.2 × longer (8.36 cm) than the untreated controls (3.72 cm). Our results elucidate the main plant factors influencing fungal community composition and demonstrate a role for endophytic fungi in P. colorata growth and further demonstrate that medicinal plants are a rich source of endophytes with potential as biocontrol agents.

Fungal Endophytes: A Promising Frontier for Discovery of Novel Bioactive Compounds

For years, fungi have served as repositories of bioactive secondary metabolites that form the backbone of many existing drugs. With the global rise in infections associated with antimicrobial resistance, in addition to the growing burden of non-communicable disease, such as cancer, diabetes and cardiovascular ailments, the demand for new drugs that can provide an improved therapeutic outcome has become the utmost priority. The exploration of microbes from understudied and specialized niches is one of the promising ways of discovering promising lead molecules for drug discovery. In recent years, a special class of plant-associated fungi, namely, fungal endophytes, have emerged as an important source of bioactive compounds with unique chemistry and interesting biological activities. The present review focuses on endophytic fungi and their classification, rationale for selection and prioritization of host plants for fungal isolation and examples of strategies that have been adopted to induce the activation of cryptic biosynthetic gene clusters to enhance the biosynthetic potential of fungal endophytes.

Exploiting endophytic microbes as micro-factories for plant secondary metabolite production

Plant secondary metabolites have significant potential applications in a wide range of pharmaceutical, food, and cosmetic industries by providing new chemistries and compounds. However, direct isolation of such compounds from plants has resulted in over-harvesting and loss of biodiversity, currently threatening several medicinal plant species to extinction. With the breakthrough report of taxol production by an endophytic fungus of Taxus brevifolia, a new era in natural product research was established. Since then, the ability of endophytic microbes to produce metabolites similar to those produced by their host plants has been discovered. The plant "endosphere" represents a rich and unique biological niche inhabited by organisms capable of producing a range of desired compounds. In addition, plants growing in diverse habitats and adverse environmental conditions represent a valuable reservoir for obtaining rare microbes with potential applications. Despite being an attractive and sustainable approach for obtaining economically important metabolites, the industrial exploitation of microbial endophytes for the production and isolation of plant secondary metabolites remains in its infancy. The present review provides an updated overview of the prospects, challenges, and possible solutions for using microbial endophytes as micro-factories for obtaining commercially important plant metabolites.Key points• Some "plant" metabolites are rather synthesized by the associated endophytes.• Challenges: Attenuation, silencing of BGCs, unculturability, complex cross-talk.• Solutions: Simulation of in planta habitat, advanced characterization methods.

The Chemistry and Pharmacology of Fungal Genus Periconia: A Review

Periconia is filamentous fungi belonging to the Periconiaceae family, and over the last 50 years, the genus has shown interest in natural product exploration for pharmacological purposes. Therefore, this study aims to analyze the different species of Periconia containing natural products such as terpenoids, polyketides, cytochalasan, macrosphelides, cyclopentenes, aromatic compounds, and carbohydrates carbasugar derivates. The isolated compound of this kind, which was reported in 1969, consisted of polyketide derivatives and their structures and was determined by chemical reaction and spectroscopic methods. After some years, 77 compounds isolated from endophytic fungus Periconia were associated with eight plant species, 28 compounds from sea hare Aplysia kurodai, and ten from endolichenic fungi Parmelia sp. The potent pharmacological agents from this genus are periconicin A, which acts as an antimicrobial, pericochlorosin B as an anti-human immunodeficiency virus (HIV), peribysin D, and pericosine A as cytotoxic agents, and periconianone A as an anti-inflammatory agent. Furthermore, information about taxol and piperine from Periconia producing species was also provided. Therefore, this study supports discovering new drugs produced by the Periconia species and compares them for future drug development.

Targeted 16S rRNA gene and ITS2 amplicon sequencing of leaf and spike tissues of Piper longum identifies new candidates for bioprospecting of bioactive compounds

Piper longum (also known as Indian long pepper) is widely used in Ayurvedic, Siddha and Unani medicine systems. The principle bioactive compound of this plant is piperine, which mainly accumulates in the fruits called spikes. The report of piperine production by endophytic microbes isolated from Piper sp., motivated us to investigate the endophytic microbial diversity associated with the spikes vis-à-vis leaves (which contain negligible levels of piperine). This is the first report to use metagenomics approach to unravel the endophytic microbial diversity in P. longum. Our results indicate that 2, 56, 631 bacterial OTUs and 1090 fungal OTUs were picked cumulatively from both the tissues. Although bacterial and fungal endophytes occupy the same niche, remarkable differences exist in their diversity and abundance. For instance, the most abundant bacterial genera in spikes were Nocardioides and Pseudonocardia (Phylum Actinobacteria; reported to produce bioactive compounds); while, in leaves were Larkinella and Hymenobacter (Phylum Bacteriodetes). Likewise, the fungal endophytes, Periconia, Cladosporium and Coniothyrium (which have been earlier reported to produce commercially important metabolites including piperine), were also present in high abundance in spikes, in comparison to leaves. Further, the results of PICRUSt analysis reveal the high metabolic potential of spike-associated bacteria for secondary metabolism, namely biosynthesis of alkaloids (including pyridine/piperidine), terpenes, flavonoids and antibiotics. Therefore, our findings indicate that the endophytes abundant or unique in spikes could be explored for bioprospecting of novel/commercially important metabolites; an approach that has both ecological and economical benefits.

Biologically Significant and Recently Isolated Alkaloids from Endophytic Fungi

A selection of the established and recently characterized alkaloids from the exploration of plant- and some marine-associated endophytic fungi is reviewed, with reference to alkaloids of biological significance.

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.

Epigenetic Modifiers Affect the Bioactive Compounds Secreted by an Endophyte of the Tropical Plant Piper longum

Seven endophytic fungi were isolated from the tropical medicinal plant Piper longum L. After preliminary screening, Phomopsis heveicola was selected for the epigenetic activation treatments. The antibacterial, antifungal, and antioxidant potentials of crude extracts obtained from the treatments (with and without epigenetic modifiers) were analyzed in vitro. The extracts inhibited growth of the human pathogens Pseudomonas aeruginosa, Shigella sonnei, Streptococcus pyogenes, and Salmonella typhi, as well as the phytopathogens Puccinia recondita, Rhizoctonia solani, Phytophthora infestans, and Botrytis cinerea. Furthermore, DPPH-scavenging activity was higher in valproic acid treated extracts. Volatile chemicals with known biological activities (measured with GC-MS/MS), were released in the valproic acid treatment. The antimicrobial potentials of the extracts were confirmed using MRM/MS analysis. The experiments revealed a new promising endophytic fungus, P. heveicola, to be utilized in biological plant protection and in biomedical applications.

Overview of the Anticancer Potential of the "King of Spices" Piper nigrum and Its Main Constituent Piperine

The main limits of current anticancer therapy are relapses, chemoresistance, and toxic effects resulting from its poor selectivity towards cancer cells that severely impair a patient's quality of life. Therefore, the discovery of new anticancer drugs remains an urgent challenge. Natural products represent an excellent opportunity due to their ability to target heterogenous populations of cancer cells and regulate several key pathways involved in cancer development, and their favorable toxicological profile. Piper nigrum is one of the most popular spices in the world, with growing fame as a source of bioactive molecules with pharmacological properties. The present review aims to provide a comprehensive overview of the anticancer potential of Piper nigrum and its major active constituents-not limited to the well-known piperine-whose undeniable anticancer properties have been reported for different cancer cell lines and animal models. Moreover, the chemosensitizing effects of Piper nigrum in association with traditional anticancer drugs are depicted and its toxicological profile is outlined. Despite the promising results, human studies are missing, which are crucial for supporting the efficacy and safety of Piper nigrum and its single components in cancer patients.

Piperine: A review of its biological effects

Medicinal plants have been used for years as a source of food, spices, and, in traditional medicine, as a remedy to numerous diseases. Piper nigrum, belonging to the family Piperaceae is one of the most widely used spices all over the world. It has a distinct sharp flavor attributed to the presence of the phytochemical, piperine. Apart from its use as a spice, P. nigrum is frequently used for medicinal, preservation, and perfumery purposes. Black pepper contains 2-7.4% of piperine, varying in content is associated with the pepper plant. Piperine displays numerous pharmacological effects such as antiproliferative, antitumor, antiangiogenesis, antioxidant, antidiabetic, anti-obesity, cardioprotective, antimicrobial, antiaging, and immunomodulatory effects in various in vitro and in vivo experimental trials. Furthermore, piperine has also been documented for its hepatoprotective, anti-allergic, anti-inflammatory, and neuroprotective properties. This review highlights and discusses the medicinal and health-promoting effects of piperine, along with possible mechanisms of its action in health promotion and disease prevention. In addition, the present review summarizes the recent literature related to piperine as a therapeutic agent against several diseases.

Fungal Composition and Diversity of the Tobacco Leaf Phyllosphere During Curing of Leaves

Rhizopus oryzae causes tobacco pole rot in China during tobacco flue-curing. Flue-curing is a post-harvest process done to prepare tobacco leaves and involves three different stages: the yellowing stage has the lowest temperatures and highest humidity, then the color-fixing stage has higher temperatures and medium humidity, and finally the stem-drying stage has the highest temperatures and lowest humidity. In this study, fungal culturing and IonS5XL high-throughput sequencing techniques were used to reveal the fungal community of the petioles and lamina of tobacco leaves infected with pole rot during flue-curing. A total of 108 fungal isolates belonging to 6 genera were isolated on media. The most common fungal species isolated was the pathogen, R. oryzae, that was most often found equally on petioles and laminas in the color-fixing stage, followed by saprotrophs, mostly Aspergillus spp. High-throughput sequencing revealed saprotrophs with Alternaria being the most abundant genus, followed by Phoma, Cercospora, and Aspergillus, whereas Rhizopus was the tenth most abundant genus, which was mostly found on petioles at the yellowing stage. Both culturable fungal diversity and fungal sequence diversity was higher at stem-drying stage than the yellowing and color-fixing stages, and diversity was higher with leaf lamina than petioles revealing that the changes in fungal composition and diversity during the curing process were similar with both methods. This study demonstrates that the curing process affects the leaf microbiome of tobacco during the curing process, and future work could examine if any of these saprotrophic fungi detected during the curing of tobacco leaves may be potential biocontrol agents for with pole rot in curing chambers.

Recent advances in inducing endophytic fungal specialized metabolites using small molecule elicitors including epigenetic modifiers

Today when the quest of new lead molecules to supply the development pipeline is driving the course of drug discovery, endophytic fungi with their outstanding biosynthetic potential seem to be highly promising avenues for natural product scientists. However, challenges such as the production of inadequate quantities of compounds, the attenuation or loss of ability of endophytes to produce the compound of interest when grown in culture and the inability of fungal endophytes to express their full biosynthetic potential in laboratory conditions have been the major constraints. These have led to the application of small chemical elicitors that induce epigenetic changes in fungi to activate their silent gene clusters optimizing the amount of metabolites of interest or inducing the synthesis of hitherto undescribed compounds. In this respect small molecular weight compounds which are known to function as inhibitors of histone deacetylase (HDAC), DNA methyltransferase (DNMT) and proteasome have proven their efficacy in enhancing or inducing the production of specialized metabolites by fungi. Moreover, organic solvents, metals and plants extracts are also acknowledged for their ability to cause shifts in fungal metabolism. We highlight the successful studies from the past two decades reporting the ability of structurally diverse small molecular weight compounds to elicit the production of previously undescribed metabolites from endophytic fungi grown in culture. This mini review argues in favor of chemical elicitation as an effective strategy to optimize the production of fungal metabolites and invigorate the pipeline of drug discovery with new chemical entities.

Exploring the different environments effect of piperine via combined crystallographic, QM/MM and molecular dynamics simulation study

Piperine is a pungent alkaloid, largely present in the skin of pepper. It is the most active component of pepper and being used as a medicine in many Asian countries. The effect of piperine on memory impairment and neurodegeneration in Alzheimer's disease model has been investigated. In the present study, we aim to investigate the effect of piperine molecule in different environments (crystal and active site of proteins) from crystallography, molecular docking, QM/MM based charge density analysis and molecular dynamic simulation. The crystal structure of piperine has been used to determine the topological electron density of intermolecular interactions. The O-atoms of piperine is forming C-H⋅⋅⋅O interactions with the neighboring molecules in the crystal, these interactions also confirmed from the Hirshfeld surface. Further, to understand the nature of interactions and the conformational flexibility of piperine in the active site of recombinant human acetylcholinesterase (rhAChE), molecular docking analysis has been performed. The selected docked complex suggests favorable hydrogen bonding and hydrophobic interactions with rhAChE enzyme; notably, the O3 atom of piperine molecule forms strong hydrogen bonding interaction with Glu202 at 1.8 Å. To determine the charge density distribution and the electrostatic properties of piperine molecule in the active site of rhAChE, the piperine-rhAChE complex was minimized at QM/MM energy level; in which, the binding pocket with piperine was considered as QM region. The charge density analysis of piperine and the interacting amino acid groups have been carried out. The topological analysis of O3⋯H-O/Glu202 hydrogen bonding interaction exhibits strong interactions and the electron density ρ_cp(r): 0.242 eÅ^-3 and the Laplacian ∇²ρ_cp(r): 3.176 eÅ^-5 respectively. These results were compared with the corresponding molecule present in the crystal and gas phase environments of piperine. The comparison of active site structure with the corresponding crystal phase and gas phase structures reveal that piperine exhibits large conformational modification in the active site. The molecular dynamics simulation and binding free energy calculations were performed, this gives the stability, binding affinity of the molecule in the active site of rhAChE. The O3⋯H-O/Glu202 interaction shows the high stability (89.2%), this was confirmed from the stability of hydrogen bond analysis. The binding free energy was used to measure the rate of inhibition of enzyme in the presence of ligand molecule. The comparative study allows to understand the nature of piperine molecule in the gas and crystal phases, and amino acids environment.

Two new cellulolytic fungal species isolated from a 19th-century art collection

The archive of the Universidad de Costa Rica maintains a nineteenth-century French collection of drawings and lithographs in which the biodeterioration by fungi is rampant. Because of nutritional conditions in which these fungi grew, we suspected that they possessed an ability to degrade cellulose. In this work our goal was to isolate and identify the fungal species responsible for the biodegradation of a nineteenth-century art collection and determine their cellulolytic activity. Fungi were isolated using potato-dextrose-agar (PDA) and water-agar with carboxymethyl cellulose (CMC). The identification of the fungi was assessed through DNA sequencing (nrDNA ITS and α-actin regions) complemented with morphological analyses. Assays for cellulolytic activity were conducted with Gram's iodine as dye. Nineteen isolates were obtained, of which seventeen were identified through DNA sequencing to species level, belonging mainly to genera Arthrinium, Aspergillus, Chaetomium, Cladosporium, Colletotrichum, Penicillium and Trichoderma. For two samples that could not be identified through their ITS and α-actin sequences, a morphological analysis was conducted; they were identified as new species, named Periconia epilithographicola sp. nov. and Coniochaeta cipronana sp. nov. Qualitative tests showed that the fungal collection presents important cellulolytic activity.

Endophytic Phomopsis sp. colonization in Oryza sativa was found to result in plant growth promotion and piperine production

Endophytic fungi have been reported to have the acquired ability to synthesize host plant specific medicinal natural products. Many fungi with such properties have been characterized and optimized for the conditions which favor maximal production of desired products. However, the inherent plant colonization property of promising endophytic fungi is least studied. Exploiting the transgenome functioning of these fungi have immense applications to add beneficial features to nonhost plants. In the present study, the endophytic fungus Phomopsis sp. isolated from Piper nigrum was confirmed for piperine production by HPLC and LCMS/MS. Further, the fungal isolate was studied for its colonization ability in Oryza sativa. Interestingly, the fungi treated plants were found to have significant plant growth enhancement when compared to the control. Further screening of extract from treated plants by HPLC and LCMS/MS resulted in the confirmation of presence of piperine. The observed result is extremely significant as it opens up novel applications of endophytic fungal colonization in taxonomically diverse plants.

Bacopaside N1 biosynthetic potential of endophytic Aspergillus sp. BmF 16 isolated from Bacopa monnieri

Chemically unique environment of endophytes makes them to have various adaptive mechanisms for survival. One of such mechanisms involves the production of pharmacologically significant plant-specific metabolites. In the present study, 26 endophytic fungi were isolated from stem of Bacopa monnieri (L.) Wettst. plants. All the isolates were screened for bacopaside production property by HPLC. Among these, the fungal isolate BmF 16 which was identified as Aspergillus sp. was confirmed for bacopaside N1 production (m/z 796) by LC-MS/MS analysis. As the extract of BMF16 used in the study was prepared from the fifth generation of culture, the obtained result can be confirmed as due to fungal production of bacopaside. In addition, this property was identified only for one among the 26 fungi screened. As bacopaside N1 production in fungi has not yet been reported, the results of the study are novel.

Natural products against Alzheimer's disease: Pharmaco-therapeutics and biotechnological interventions

Alzheimer's disease (AD) is a severe, chronic and progressive neurodegenerative disease associated with memory and cognition impairment ultimately leading to death. It is the commonest reason of dementia in elderly populations mostly affecting beyond the age of 65. The pathogenesis is indicated by accumulation of the amyloid-beta (Aβ) plaques and neurofibrillary tangles (NFT) in brain tissues and hyperphosphorylation of tau protein in neurons. The main cause is considered to be the formation of reactive oxygen species (ROS) due to oxidative stress. The current treatment provides only symptomatic relief by offering temporary palliative therapy which declines the rate of cognitive impairment associated with AD. Inhibition of the enzyme acetylcholinesterase (AChE) is considered as one of the major therapeutic strategies offering only symptomatic relief and moderate disease-modifying effect. Other non-cholinergic therapeutic approaches include antioxidant and vitamin therapy, stem cell therapy, hormonal therapy, use of antihypertensive or lipid-lowering medications and selective phosphodiesterase (PDE) inhibitors, inhibition of β-secretase and γ-secretase and Aβ aggregation, inhibition of tau hyperphosphorylation and intracellular NFT, use of nonsteroidal anti-inflammatory drugs (NSAIDs), transition metal chelators, insulin resistance drugs, etanercept, brain-derived neurotrophic factor (BDNF) etc. Medicinal plants have been reported for possible anti-AD activity in a number of preclinical and clinical trials. Ethnobotany, being popular in China and in the Far East and possibly less emphasized in Europe, plays a substantial role in the discovery of anti-AD agents from botanicals. Chinese Material Medica (CMM) involving Chinese medicinal plants has been used traditionally in China in the treatment of AD. Ayurveda has already provided numerous lead compounds in drug discovery and many of these are also undergoing clinical investigations. A number of medicinal plants either in their crude forms or as isolated compounds have exhibited to reduce the pathological features associated with AD. In this present review, an attempt has been made to elucidate the molecular mode of action of various plant extracts, phytochemicals and traditional herbal formulations investigated against AD as reported in various preclinical and clinical tests. Herbal synergism often found in polyherbal formulations were found effective to combat disease heterogeneity as found in complex pathogenesis of AD. Finally a note has been added to describe biotechnological improvement, genetic and genomic resources and mathematical and statistical techniques for empirical model building associated with anti-AD plant secondary metabolites and their source botanicals.

Endophytes as in vitro production platforms of high value plant secondary metabolites

Many reports have been published on bioprospecting of endophytic fungi capable of producing high value bioactive molecules like, paclitaxel, vincristine, vinblastine, camptothecin and podophyllotoxin. However, commercial exploitation of endophytes for high value-low volume plant secondary metabolites remains elusive due to widely reported genomic instability of endophytes in the axenic culture. While most of the endophyte research focuses on screening endophytes for novel or existing high value biomolecules, very few reports seek to explore the possible mechanisms of production of host-plant associated or novel secondary metabolites in these organisms. With an overview of host-endophyte relationship and its possible impact on the secondary metabolite production potential of endophytes, the review highlights the evidence reported for and against the presence of host-independent biosynthetic machinery in endophytes. The review aims to address the question, why should and how can endophytes be exploited for large scale in vitro production of high value phytochemicals? In this regard, various bioprocess optimization strategies that have been applied to sustain and enhance the product yield from the endophytes have also been described in detail. Further, techniques like mixed fermentation/co-cultivation and use of epigenetic modifiers have also been discussed as potential strategies to activate cryptic gene clusters in endophytes, thereby aiding in novel metabolite discovery and overcoming the limitations associated with axenic culture of endophytes.

Endophytic fungi: a reservoir of antibacterials

Multidrug drug resistant bacteria are becoming increasingly problematic particularly in the under developed countries of the world. The most important microorganisms that have seen a geometric rise in numbers are Methicillin resistant Staphylococcus aureus, Vancomycin resistant Enterococcus faecium, Penicillin resistant Streptococcus pneumonia and multiple drug resistant tubercule bacteria to name a just few. New drug scaffolds are essential to tackle this every increasing problem. These scaffolds can be sourced from nature itself. Endophytic fungi are an important reservoir of therapeutically active compounds. This review attempts to present some data relevant to the problem. New, very specific and effective antibiotics are needed but also at an affordable price! A Herculean task for researchers all over the world! In the Asian subcontinent indigenous therapeutics that has been practiced over the centuries such as Ayurveda have been effective as "handed down data" in family generations. May need a second, third and more "in-depth investigations?"

Phylogenetic and chemical diversity of fungal endophytes isolated from Silybum marianum (L) Gaertn. (milk thistle)

Use of the herb milk thistle (Silybum marianum) is widespread, and its chemistry has been studied for over 50 years. However, milk thistle endophytes have not been studied previously for their fungal and chemical diversity. We examined the fungal endophytes inhabiting this medicinal herb to determine: (1) species composition and phylogenetic diversity of fungal endophytes; (2) chemical diversity of secondary metabolites produced by these organisms; and (3) cytotoxicity of the pure compounds against the human prostate carcinoma (PC-3) cell line. Forty-one fungal isolates were identified from milk thistle comprising 25 operational taxonomic units based on BLAST search via GenBank using published authentic sequences from nuclear ribosomal internal transcribed spacer sequence data. Maximum likelihood analyses of partial 28S rRNA gene showed that these endophytes had phylogenetic affinities to four major classes of Ascomycota, the Dothideomycetes, Sordariomycetes, Eurotiomycetes, and Leotiomycetes. Chemical studies of solid-substrate fermentation cultures led to the isolation of four new natural products. In addition, 58 known secondary metabolites, representing diverse biosynthetic classes, were isolated and characterized using a suite of nuclear magnetic resonance and mass spectrometry techniques. Selected pure compounds were tested against the PC-3 cell line, where six compounds displayed cytotoxicity.

Osmoregulatory and tegumental ultrastructural damages to protoscoleces of hydatid cysts Echinococcus granulosus induced by fungal endophytes

Characteristic ultrastructural changes were observed when protoscoleces of hydatid cysts Echinococcus granulosus was treated with extract of endophytic fungi Eupenicillium and Chaetomium sp. isolated from Azadirachta indica and Piper longum plants respectively. A sharp decrease in viability of protoscoleces was observed after 6 h of incubation with fungal extracts. The ultrastructural changes included rosteller disorganization, loss of hooks and shedding of the microtriches of scolex region. The formation of digitiform projections on tegument layer which, increased in size as prolong incubation with extract and get burst, leading to a osmoregulatory damage into tegumental layers of parasite. This osmoregulatory damages caused the loss of turgidity due to leakage of cell contents, which might be the major cause of the mortality in treated parasites. It is remarkable, since very similar type of ultrastructural changes were observed with some pyrazinoisoquinoline derivatives, as praziquantel. Our initial results indicate that extract of endophytic Eupenicillium and Chaetomium spp. are having significant anti-cestodal activity and have selective activity on tegument layer. Further chemical prospection is required through rigorous bioassay guided fractionation coupled with robust high resolution mass spectrometric analysis to get final stereo-structures responsible for the parasiticidal activity. This initial strain selection outcome will serve a platform for isolation and characterization of new drug lead that can be useful in tailoring novel, safe and effective anthelmintics.

Piperine production by endophytic fungus Colletotrichum gloeosporioides isolated from Piper nigrum

Many endophytic fungi have been reported with the biosynthetic potential to produce same or similar metabolites present in host plants. The adaptations that might have acquired by these fungi as a result of the long-term association with their host plants can be the possible basis of their biosynthetic potential. The bioactive compounds originated from endophytes are currently explored for their potential applications in pharmaceutical, agriculture and food industries. Piper nigrum, a plant of the Piperaceae is very remarkable because of the presence of the alkaloid piperine. Piperine has been reported to have broad bioactive properties ranging from antimicrobial, antidepressant, anti-inflammatory, antioxidative to anticancer activities. Interestingly, piperine also plays a vital role in increasing the bioavailability of many drugs which again is a promising property. The current study was carried out to identify piperine producing endophytic fungus from Piper nigrum L. By screening various endophytic fungi, the isolate which was identified as member of Colletotrichum gloeosporioides was found to have the ability to form piperine and was confirmed by HPLC and LCMS. Considering the broad bioactive potential of piperine, the piperine producing fungi identified in the study can expect to have much industrial potential.

Anticestodal activity of endophytic Pestalotiopsis sp. on protoscoleces of hydatid cyst Echinococcus granulosus

Surgery is still the main treatment in hydatidosis caused by Echinococcus, which is a global health problem in human and animals. So, there is need for some natural protoscolicidal agents for instillation to prevent their reoccurrence at therapeutic doses. In this present investigation, anticestodal activity of one of the endophytic fungi Pestalotiopsis sp. from Neem plant was observed on protoscoleces of hydatid cysts of Echinococcus granulosus. Viability of protoscoleces was confirmed by 0.1% aqueous eosin red stain method, where mortality was observed at different concentrations with respect to time. An average anticestodal activity was observed with different endophytic fungal strains, that is, Nigrospora (479 ± 2.9), Colletotrichum (469 ± 25.8), Fusarium (355 ± 14.5), and Chaetomium (332 ± 28.3) showing 64 to 70% protoscolicidal activity, except Pestalotiopsis sp. (581 ± 15.0), which showed promising scolicidal activity up to 97% mortality just within 30 min of incubation. These species showed significant reduction in viability of protoscoleces. This is the first report on the scolicidal activity of endophytic Pestalotiopsis sp. We conclude that ultrastructural changes in protoscoleces were due to endophytic extract suggesting that there may be some bioactive compounds that have selective action on the tegument layer of protoscoleces. As compared with that of standard drug used, endophytic species of Neem plant shows significant anticestodal activity.

Benzophenones from an endophytic fungus, Graphiopsis chlorocephala, from Paeonia lactiflora cultivated in the presence of an NAD+-dependent HDAC inhibitor

Graphiopsis chlorocephala was separated from the surface-sterilized healthy leaves of Paeonia lactiflora (Paeoniaceae) and cultivated with nicotinamide (an NAD(+)-dependent HDAC inhibitor). The culture conditions significantly enhanced secondary metabolite production in the fungus and led to the isolation of a structurally diverse set of new benzophenones, cephalanones A-F (1-6), and a known 2-(2,6-dihydroxy-4-methylbenzoyl)-6-hydroxybenzoic acid (7). The structures of 1-6 were determined from NMR data, single crystal X-ray diffraction, and chemical transformations.

Generic and functional diversity in endophytic actinomycetes from wild Compositae plant species at South Sinai - Egypt

The diversity of culturable endophytic actinomycetes associated with wild Compositae plants is scantily explored. In this study, one hundred and thirty one endophytic actinobacteria were isolated from ten Compositae plant species collected from South Sinai in Egypt. Microscopic and chemotaxonomic investigation of the isolates indicated fourteen genera. Rare genera, such as Microtetraspora, and Intrasporangium, which have never been previously reported to be endophytic, were identified. Each plant species accommodated between three to eight genera of actinobacteria and unidentified strains were recovered from seven plant species. The generic diversity analysis of endophytic assemblages grouped the plant species into three main clusters, representing high, moderate and low endophytic diversity. The endophytes showed high functional diversity, based on forty four catabolic and plant growth promotion traits; providing some evidence that such traits could represent key criteria for successful residence of endophytes in the endosphere. Stress-tolerance traits were more predictive measure of functional diversity differences between the endophyte assemblages (Shannon's index, p = 0.01). The results indicate a potential prominent role of endophytes for their hosts and emphasize the potency of plant endosphere as a habitat for actinobacteria with promising future applications.