Saccharopolyspora: an underexplored source for bioactive natural products

Actinomycetes are a rich source for secondary metabolites with a diverse array of biological activities. Among the various genera of actinomycetes, the genus Saccharopolyspora has long been recognized as a potential source for antibiotics and other therapeutic leads that belong to diverse classes of natural products. Members of the genus Saccharopolyspora have been widely reported from several natural sources including both terrestrial and marine environments. A plethora of this genus has been chemically investigated for the production of novel natural products with interesting pharmacological effects. Therefore, Saccharopolyspora is considered one of the pharmaceutical important genera that could provide further chemical diversity with potential lead compounds. In this review, the literature from 1976 until December 2018 was covered, providing a comprehensive survey of all natural products derived from this genus and their semi-synthetic derivatives along with their biological activities, whenever applicable. Moreover, the biological diversity of Saccharopolyspora species and their habitats were also discussed.     

Significance of the zebrafish model in the discovery of bioactive molecules from nature

Natural products have immense therapeutic potential not only due to their structural variation and complexity but also due to their range of biological activities. Research based on natural products has led to the discovery of molecules with biomedical and pharmaceutical applications in different therapeutic areas like cancer, inflammation responses, diabetes, and infectious diseases. There are still several challenges to be overcome in natural product drug discovery research programs and the challenge of high throughput screening of natural substances is one of them. Bioactivity screening is an integral part of the drug discovery process and several in vitro and in vivo biological models are now available for this purpose. Among other well-reported biological models, the zebrafish (Danio rerio) is emerging as an important in vivo model for preclinical studies of synthetic molecules in different therapeutic areas. Zebrafish embryos have a short reproductive cycle, show ease of maintenance at high densities in the laboratory and administration of drugs is a straightforward procedure. The embryos are optically transparent, allowing for the visualization of drug effects on internal organs during the embryogenesis process. In this review, we illustrate the importance of using zebrafish as an important biological model in the discovery of bioactive drugs from natural sources.     

Secondary metabolites of soil <Emphasis Type="Italic">Bacillus</Emphasis> spp.

Bacillus species produce secondary metabolites that are the object of natural product chemistry studies. The wide structural variability of these compounds has attracted the curiosity of chemists and their biological activities have inspired the pharmaceutical industry to search for lead structures in microbial extracts. Screening of microbial extracts reveals the large structural diversity of natural compounds with broad biological activities, such as antimicrobial, antiviral, immunosuppressive, and antitumor activities, that enable the bacterium to survive in its natural environment. These findings widen the potential industrial importance of Bacillus spp., particularly of B. thuringiensis, beyond insecticidal usage and may help explain the role of Bacillus spp. in the soil ecosystem.     

Antioxidant,Anti‐inflammatory and Cytotoxic Activities of Polyphenols Extracted from Chroogomphus rutilus

Chroogomphus rutilus is a rare fungal species that grows under pine trees and is now widely used as a functional food and pharmaceutical product. However, the chemical constituents and biological activities of Chroogomphus rutilus have been relatively limited. The present study aimed at determining the total polyphenols and flavonoids contents, biological activities and main phenolic compounds of Chroogomphus rutilus from different geographical origins at the stipe and pileus. The results suggested that Chroogomphus rutilus polyphenol extracts revealed a higher antioxidant, anti‐inflammatory, and cytotoxic activities, and there were significant differences between samples from different locations and regions. Correlation analysis showed that the contents of total polyphenols and flavonoids were significantly correlated with antioxidant and anti‐inflammatory activities. However, only the content of total flavonoids was significantly correlated with cytotoxicity, which means that the cytotoxicity of Chroogomphus rutilus polyphenol extracts may be regulated by flavonoids or other compounds. HPLC‐DAD analysis revealed that the main phenolic compound was protocatechuic acid, followed by baicalin, p‐hydroxyphenylacetic acid and p‐hydroxybenzoic acid, but comparing with the pileus extracts, the stipe extracts can be considered as a higher concentration of phenolic compounds. Therefore, antioxidant, anti‐inflammatory and cytotoxic activities of Chroogomphus rutilus polyphenol extracts could be due to the identified compounds. This study investigated a deep knowledge about the constituents and activities of Chroogomphus rutilus and provided the reference for its application in food and pharmaceutical.     

Chemical Composition,Antioxidant Potential and Enzymes Inhibitory Properties of Globe Artichoke By‐Products

In this study, chemical composition and in vitro biological activities of artichoke by‐products (leaves, floral stems and bracts) issued from two Tunisian varieties were evaluated. Analysis was performed by means of high‐performance liquid chromatography with diode array detection coupled to electrospray ionization mass spectrometric (LC/DAD/ESI‐MS). Total phenolic (TPC) and flavonoid (TFC) contents as well as the antioxidant activity conducted by three complementary methods, DPPH, ABTS and FRAP tests, were performed for each sample. Enzyme inhibitory effects against acetylcholinesterase, butyrylcholinesterase and α‐amylase were also studied. Results showed that TPC and TFC varied according to variety as well as the plant part. Bracts presented the highest TPC values (10–15 mg GAE/g DW), while leaves were distinguished by the highest TFC values (52–58 mg EQ/g DW). In vitro assays showed that Violet d'Hyères bracts and Blanc d'Oran leaves present the most antioxidant activities (30.040 and 20.428 mgET/gDW, respectively, by the DPPH method). Leaves demonstrated the highest acetylcholinesterase and butyrylcholinesterase inhibitory effects. Moreover, all organs displayed a noticeable inhibition towards α‐amylase. LC/DAD/MS analysis revealed that artichoke by‐products are a potential source of biopharmaceuticals such as luteolin derivatives from leaves and mono/dicaffeoylquinic acids in the other parts. This research demonstrates that globe artichoke by‐products, unexploited in our country, are a promising source of natural health promoting compounds with potential applications in the food and pharmaceutical industries.     

Nontraditional microbial bioactive metabolites

Microorganisms produce low-molar-mass secondary metabolites exhibiting different biological activities, which are used.e.g., in medicine as antimicrobial and antifungal agents, alkaloids and toxins. Some of these substances have highly diverse biological activities and unusual structures. They are produced by streptomycetes, fungi, and bacilli, but interesting products have also been obtained from microorganisms growing in extreme conditions. Several thousands of microbial products have so far been discovered and many other, which can be potentially useful, and/or prospective for human use, can still be in the offing.     

Insect bioactive compounds and their potential use in animal diets and medicine

This study examined the effects of various insect species, such as those of Bombyx mori, Hermetia illucens and Tenebrio monitor, that have long been used in combination with medicinal plants and are an important alternative to modern medicine in many parts of the world. The current use of traditional pesticides from around the year 2010 and the characteristics of isolated biologically active molecules are also presented. Natural insect products were examined or isolated from ants, bees, beetles, cockroaches, termites, bees, etc. The biological activities of these natural products derived from insects include antimicrobial, antifungal, anticancer, antiviral, antioxidant and anti-inflammatory effects. Insect additives to animal feed rarely distort the relevant physicochemical variables or sensory profile of the meat, whereas the fatty acid (FA) profile is discernibly changed. In fact, insect derivatives have great potential for future drug discovery in natural products, as well as for the production of nutritious foods for humans and for animals. It is concluded that the inoculation of insect powder in animal feeds results in the prevention and treatment of disease, enhances the growth of animals and promotes the bioactive compounds in animal-based products. Owing to the sustainability of their breeding, large-scale cultures of these insects seem economically viable. Insect oil and protein as well as chitin ingredients are widely used in cosmetics, and these substances are considered high-value co-products. The major challenges associated with their use will be linked to the development of methods for separating industrial-derived materials.     

Recent Updates on Corals from Nephtheidae

Marine natural products display a wide range of biological activities, which play a vital role in the innovation of lead compounds for the drug development. Soft corals have been ranked at the top in regard to the discovery of bioactive metabolites with potential pharmaceutical applications. Many of the isolated cembranoids revealed diverse biological activities, such as anticancer, antidiabetic and anti‐osteoporosis. Likewise, sterols from soft corals exhibited interesting biological potential as anti‐inflammatory, antituberculosis and anticancer. Consequently, investigating marine soft corals will definitely lead to the discovery of a large number of chemically varied secondary metabolites with countless bioactivities for possible applications in medicine and pharmaceutical industry. This review provides a complete survey of all metabolites isolated from the family Nephtheidae, from 2011 until November 2018, along with their natural sources and biological potential whenever possible.     

生物大分子从头合成和设计的研究进展

生物大分子指生物体内存在的DNA、蛋白质、多糖等物质,其对生物体正常生命活动至关重要.从头合成和设计技术在生物大分子的合成和结构设计上具有自由度高、前体简单等特点,能够按照特定研究目的对生物大分子进行全新设计和高效合成.近年来,从头合成与设计技术在人造基因组合成、新型蛋白质类药物设计、糖缀合物合成等领域已开始受到重视.基于生物大分子从头合成和设计技术,可以定向制备全新设计的DNA或全新的基因表达产物,以及具有识别功能的糖链或糖缀合物,将大大推进诸如细胞因子模拟物、基因治疗递送载体等生物活性物质的开发,为人工生物系统的构建、罕见疾病的治疗等提供新的解决方法.本文就DNA、蛋白质和多糖的从头合成和设计进行了综述,阐述了相关方法及应用,最后概括分析了三者之间的关系.     

Natural Monoterpenes: Much More than Only a Scent

Terpenes are a widespread group of secondary metabolites that can be found in various family plants such as the Lamiaceae. In view of their numerous valuable biological activities, the industrial production of concrete terpenes and essential oils rich in the substances is intensively studied. Monoterpenes constitute a significant part of the whole group of the aforementioned secondary metabolites. This is due to their numerous biological activities and their ability to permeate the skin. Despite the fact that these substances have gain popularity, they are not comprehensively characterized. The presented review is based on studies of the biological activities of the most important monoterpenes and the essential oils rich in these compounds. The authors focused attention on antioxidant activity, inhibition towards acetyl‐ and butyrylcholinesterase, and α‐amylase and α‐glucosidase, antifungal, hepatoprotective, sedative properties, and their skin permeation enhancement.     

Amino‐substituted para‐Benzoquinones as Potential Herbicides

Although quinones present a large array of biological activities, a few studies on the herbicidal potential of 2,5‐bis(alkyl/arylamino)‐1,4‐benzoquinones have been reported to date. In this work, starting from benzoquinone, 13 2,5‐bis(alkyl/arylamino)‐1,4‐benzoquinones were prepared in 46 – 93% yield. The products were fully characterized by spectroscopic analyses and their phytotoxicity against Cucumis sativus and Sorghum bicolor seedlings was investigated. At 100 ppm, compounds caused 10 – 88% growth inhibition of the dicotyledonous species, whereas the monocotyledon was less affected. Most compounds exerted little inhibitory effect on a cyanobacterial model strain. However, at 100 μm , compounds 8  –  10 caused about 50% inhibition of algal growth, and compounds 1 and 2 reduced cell viability in the 1 – 10 μm range. The ability of benzoquinone derivatives to interfere with the light‐driven ferricyanide reduction by isolated spinach chloroplasts was evaluated. Some substances showed a moderate effect as uncouplers, but no relationship was found between this property and their biological activity, indicating that the herbicidal effect is not associated with the inhibition of the photosynthetic electron transport chain. Phytotoxic compounds were not toxic to insects, strengthening the possibility that they may serve as lead for the development of eco‐friendly herbicides.     

Secondary Metabolites from Marine Micromonospora: Chemistry and Bioactivities

Marine Micromonospora was revealed to be a rather untapped and a rich source of chemically diverse and unique bioactive natural products. This review is aimed to make a comprehensive survey of secondary metabolites that were derived from marine Micromonospora including chemical diversity and biological activities. A total of 116 compounds from 41 marine Micromonospora species have been reported, covering the literatures from 1997 to 2019. These compounds contain several structural classes such as polyketides (PKS), nonribosomal peptides (NRPS), PKS‐NRPS hybrids, terpenes and others, and they present cytotoxic, antibacterial, antiparasitic, chemopreventive or antioxidant activities.     

海洋动物来源活性物质的研究新进展

海洋动物因具有产生抗菌物质、抗肿瘤物质、抗病毒物质、免疫调节物质等活性产物的巨大潜力,备受研究人员重视。近年来,各 国研究者已从海洋动物中分离出了数千种结构新颖的活性物质,为新药的开发提供了坚实的基础。简要介绍了近六年来海绵、珊瑚、海参、 海鞘等海洋动物来源的活性物质研究进展,旨在为海洋药用动物资源的开发利用提供参考。     

Isolation and characterization of hydrocarbon-degrading and biosurfactant-producing yeast strains obtained from a polluted lagoon water

Microbial surfactants are environmentally friendly products with amazing properties and spectrum of applications. It is therefore, not surprising that research has increased in recent time with the objectives of sourcing for novel surface-active compounds with dual functions in oil and pharmaceutical industries. Evaluation of hydrocarbon degrading potentials and emulsifying activities indicated that biosurfactants were produced by two newly isolated and promising yeast strains, Saccharomyces cerevisiae and Candida albicans, obtained from a polluted lagoon water. Both strains were able to grow effectively on crude oil and diesel as sole sources of carbon and energy. Growth curves on diesel were obtained to establish the relation between cell growth and biosurfactant production. The growth peak was on the 8th day while the specific growth rate ranged insignificantly (P < 0.05) between 0.46 and 0.48 day⁻¹. Interestingly, biosurfactant was detected on the 2nd day when growth was almost inexistent, with maximal production obtained at stationary/death phase of growth. The partially-purified biosurfactants exhibited antimicrobial activities by completely inhibiting the growth of clinical strains of Escherichia coli and Staphylococcus aureus at all concentrations tested. Although C. albicans appeared to be a better diesel-utilizer and biosurfactant-producer (E₂₄ = 64.2%), the potency of its surfactant was smaller than that of S. cerevisiae. These strains represent a new class of biosurfactant producers that have potential for use in a variety of biotechnological and industrial processes particularly in the pharmaceutical industry.     

Biologically active oxylipins from seaweeds

Our previous research has shown that many red algae metabolize polyunsaturated fatty acids to oxidized products resembling the eicosanoid hormones from mammals. We have extended these studies to members of the Phaeophyceae and Chlorophyta and find they also possess similar biosynthetic pathways. From several we have identified novel prostaglandin-like substances. Studies of the molecular mechanisms by which some of these marine oxylipins are formed have revealed that novel oxidative reactions are utilized. Understanding of these biosynthetic pathways in detail has allowed their utilization to produce research biochemicals of high value, such as 12S-hydroperoxyeicosatetraenoic acid (12S-HPETE). Because of their biological properties, seaweed-derived oxylipins have potential utility as pharmaceuticals and research biochemicals.     

In vitro assessment of adsorbents aiming to prevent deoxynivalenol and zearalenone mycotoxicoses

The high prevalence of the Fusarium mycotoxins, deoxynivalenol (DON) and zearalenone (ZON) in animal feeds in mild climatic zones of Europe and North America results in considerable economic losses, as these toxins affect health and productivity particularly of pigs from all age groups. The use of mycotoxin adsorbents as feed additives is one of the most prominent approaches to reduce the risk for mycotoxicoses in farm animals, and to minimise carry-over of mycotoxins from contaminated feeds into foods of animal origin. Successful aflatoxin adsorption by means of different substances (phyllosilicate minerals, zeolites, activated charcoal, synthetic resins or yeast cell-wall-derived products) has been demonstrated in vivo and in vitro. However, attempts to adsorb DON and ZON have been less encouraging. Here we describe the adsorption capacity of a variety of potential binders, including compounds that have not been evaluated before, such as humic acids. All compounds were tested at realistic inclusion levels for their capacity to bind ZON and DON, using an in vitro method that resembles the different pH conditions in the gastro-intestinal tract of pigs. Mycotoxin adsorption was assessed by chemical methods and distinct bioassays, using specific markers of toxicity as endpoints of toxicity in cytological assays. Whereas none of the tested substances was able to bind DON in an appreciable percentage, some of the selected smectite clays, humic substances and yeast-wall derived products efficiently adsorbed ZON (>70%). Binding efficiency was indirectly confirmed by the reduction of toxicity in the in vitro bioassays. In conclusion, the presented test protocol allows the rapid screening of potential mycotoxin binders. Like other in vitro assays, the presented protocol combining chemical and biological assays cannot completely simulate the conditions of the gastro-intestinal tract, and hence in vivo experiments remain mandatory to assess the efficacy of mycotoxin binders under practical conditions.     

Antioxidants,Enzyme Inhibitors,and Biogenic Compounds in Grain Extracts of Barleys

The content of biogenic compounds and the biological activities of barley (Hordeum vulgare L.)‐grain extracts was evaluated. The sufficiently large and heterogeneous set of barley genotypes (100 accessions) enabled the selection of special genotypes interesting for potential industrial, pharmaceutical, and medicinal applications. Barley genotypes with the highest contents of phenols, phenolic acids, flavonoids, biogenic thiols, and amines, radical‐scavenging activity, as well as inhibitory activities of trypsin, thrombin, collagenase, urokinase, and cyclooxygenase were identified.     

Chemistry and Bioactivity of the Genus Persea - A Review

This review provides the first comprehensive appraisal of bioactive compounds and their biological activities in Persea species from 1950 to 2023. Relevant articles from reputable databases, including PubMed, Web of Science, Science Direct and Google Scholar were collected, leading to the isolation of about 141 metabolite compounds, mainly flavonoids, terpenoids, fatty alcohols, lignoids, and γ-lactone derivatives. These compounds exhibit diverse biological activities, including insecticidal, antifeedant, nematicidal, antibacterial, antifungal, antiviral, cytotoxic, anti-inflammatory, and antioxidant properties. The review emphasizes the significant chemical and pharmacological potential of different Persea species, encouraging further research in various fields and medicine. Valuable insights into potential applications of Persea plants are provided.     

Production and metabolic engineering of bioactive substances in plant hairy root culture

In the past three decades, hairy roots research for the production of valuable biological active substances has received a lot of attention. The addition of knowledge to enhance the yields of desired substances and the development of novel tools for biomass engineering offer new possibilities for large-scale cultivation of the plant hairy root. Hairy roots can also produce recombinant proteins through the transfer of Agrobacterium T-DNA into the plant genome, and thereby hold immense potential for the pharmaceutical industry. This review highlights some of the significant progress made in the past few years and outlines future prospects for exploiting the potential utility of hairy root cultures as “chemical factories” for producing bioactive substances.