Progress in the chemistry of organic natural products最新文献

Little prior attention has been paid to the use of bryophytes in the human diet as foods, cosmetics, and medicines, despite there being 23,000 species known worldwide. Some mosses and liverworts produce significant levels of terpenoids and phenolic compounds possessing characteristic odors and tastes, as well as exhibiting cytotoxic, antioxidant, muscle relaxant, anti-inflammatory, antiobesity, and many other activities. In addition, vitamin B₂ and tocopherols, as well as prostaglandin-like highly unsaturated fatty acids are produced by these organisms. In this contribution, the distribution in bryophytes of terpenoids, aromatic compounds, and polyketides, having biological and pharmacological activity, and their possible uses as cosmetics and foods, and in drug development are discussed.

Australia is home to some of the oldest continuously rainforested ecosystems on earth. These forests contain a rich diversity of unique flora that reflect their origins from ancestors that were once widespread on the supercontinent Gondwana. Although rainforests represent 3% of Australian native forests (36,000 km²) and cover only 0.024% of earths land area, they contain ~3,800 gymnosperm and angiosperm species from 187 families and 942 genera. This phylogenetically diverse flora contains a rich diversity of natural products. The antiquity of the Australian rainforest flora matches with ancient biosynthetic lineages, and this has resulted in their natural product chemistry being remarkably diverse. Only 10% of the rainforest species have been investigated, but these studies have yielded almost 2,400 constituents. This contribution discusses the diversity of Australian rainforest derived natural products in relation to current knowledge on the origins, phylogenetic diversification and dispersal of seed plants. Ancient lineages appear to be reservoirs of high chemical diversity, and this highlights Australia's rainforests as a living museum of natural product chemical diversity. This volume highlights key highly bioactive natural products that have been isolated from Australian rainforest species and discusses recent NMR spectroscopic methods that have been developed to help identify unique molecules in complex mixtures in Australian rainforest species. It also discusses the significant contribution that Australian rainforest derived natural products play in our understanding of worldwide seed plant chemical diversity.

This contribution provides a comprehensive review of the biologically active compounds present in 21 high-value medicinal and aromatic plant species from Malaysia, with a particular focus on their phytochemical diversity and biological activities. Several plants, including well-known species such as Eurycoma longifolia, Andrographis paniculata, Morinda citrifolia, Centella asiatica, and Moringa oleifera, have been designated as high-priority herbal products under Malaysia's National Key Economic Area (NKEA) in the Eleventh Malaysia Plan (RMK-11). Their significance extends beyond traditional uses in herbal medicine, as they are being recognized increasingly for their potential to contribute to the national economy and modern healthcare solutions. The compilation provided describes the pharmacological properties of these plants, highlighting their anti-inflammatory, antioxidant, antimicrobial, and cytotoxic activities, among others. Additionally, the aromatic plants Clinacanthus nutans, Cananga odorata, Citrus hystrix, and Polygonum minus are included in terms of their bioactive compounds produced and their potential therapeutic and industrial applications. By highlighting the relevant current research, this compilation aims to provide valuable insight for researchers, policymakers, and industry stakeholders, in terms of enhancing the understanding of both the therapeutic potential of these plants and their possible future contributions to healthcare and sustainable economic development.

Plants are excellent chemists with an impressive capability of biosynthesizing a large variety of natural products (also known as secondary or specialized metabolites) to resist various biotic and abiotic stresses. In this chapter, 989 plant natural products and their ecological functions in plant-herbivore, plant-microorganism, and plant-plant interactions are reviewed. These compounds include terpenoids, phenols, alkaloids, and other structural types. Terpenoids usually provide direct or indirect defense functions for plants, while phenolic compounds play important roles in regulating the interactions between plants and other organisms. Alkaloids are frequently toxic to herbivores and microorganisms, and can therefore also provide defense functions. The information presented should provide the basis for in-depth research of these plant natural products and their natural functions, and also for their further development and utilization.

The development of efficient methods for dereplication has been critical in the re-emergence of the research in natural products as a source of drug leads. Current dereplication workflows rapidly identify already known bioactive secondary metabolites in the early stages of any drug discovery screening campaign based on natural extracts or enriched fractions. Two main factors have driven the evolution of natural products dereplication over the last decades. First, the availability of both commercial and public large databases of natural products containing the key annotations against which the biological and chemical data derived from the studied sample are searched for. Second, the considerable improvement achieved in analytical technologies (including instrumentation and software tools) employed to obtain robust and precise chemical information (particularly spectroscopic signatures) on the compounds present in the bioactive natural product samples. This chapter describes the main methods of dereplication, which rely on the combined use of large natural product databases and spectral libraries, alongside the information obtained from chromatographic, UV-Vis, MS, and NMR spectroscopic analyses of the samples of interest.

A lichen is a symbiotic association composed of a primary mycobionts and one or more photobionts living mutualistically together, forming a distinct morphological entity beneficial to their partnership and to other associated fungi, photobionts, and bacteria that collectively make up the lichen biome. The taxonomic identification of a lichen species often requires determination of the primary mycobiont's secondary metabolites, the key morphological characteristics of the thallus, and how it relates to other lichen species as seen in DNA phylogeny. This chapter covers lichens and their bionts, taxonomic identification, and their chemical constituents as exemplified by what is found in lichen biomes, especially those endemic to North America. Extraction and isolation, as well as updates on dereplication methods using mass spectrometric GNPS and NMR spectroscopic spin network fingerprint procedures, and marker-based techniques to identify lichens are discussed. The isolation and structure elucidation of secondary metabolites of an endolichenic Penicillium species that produces bioactive compounds will be described in detail.

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

The distribution, chemistry, and molecular bioactivity of tiglianes are reviewed from the very beginning of the studies on these diterpenoids, summarizing their clinical and toxicological literature mostly in its more recent and controversial aspects, and critically analyzing various proposals for their biosynthesis.

This book describes a unique class of secondary metabolites, the mono- and dimeric naphthylisoquinoline alkaloids. They occur in lianas of the paleotropical Ancistrocladaceae and Dioncophyllaceae families, exclusively. Their unprecedented structures include stereogenic centers and rotationally hindered, and thus likewise stereogenic, axes. Extended recent investigations on six Ancistrocladus species from Asia, as reported in this review, shed light on their fascinating phytochemical productivity, with over 100 such intriguing natural products. This high chemodiversity arises from a likewise unique biosynthesis from acetate-malonate units, following a novel polyketidic pathway to plant-derived isoquinoline alkaloids. Some of the compounds show most promising antiparasitic activities. Likewise presented are strategies for the regio- and stereoselective total synthesis of the alkaloids, including the directed construction of the chiral axis.

The widespread utility of herbal products has been rising considerably worldwide, including both developed and developing countries, leading to the rapid growth of their availability in the United States and globally. This substantial increase in consumption of herbal products has witnessed the emergence of adverse effects upon oral administration of certain of these products, and thus has raised safety concerns. The adverse effects caused by the consumption of certain botanical medicines occur primarily as a result of the poor quality of plant raw materials or the finished products, which inherently may affect safety and/or efficacy. The poor quality of some herbal products can be attributed to a lack of proper quality assurance and quality control. A high demand for herbal products that surpasses production, combined with a desire for maximizing profits, along with a lack of rigorous quality control within some manufacturing facilities have led to the emergence of quality inconsistencies. The underlying causes for this involve the misidentification of plant species, or their substitution, adulteration, or contamination with harmful ingredients. Analytical assessments have revealed there to be frequent and significant compositional variations between marketed herbal products. The inconsistency of the quality of herbal products can be ascribed essentially to the inconsistency of the botanical raw material quality used to manufacture the products. Thus, the quality assurance and the quality control of the botanical raw materials is may contribute significantly to improving the quality and consistency of the quality of the end products. The current chapter focuses on the chemical evaluation of quality and consistency of herbal products, including botanical dietary supplements. Different techniques, instruments, applications, and methods used in identifying, quantifying, and generating chemical fingerprints and chemical profiles of the ingredients of the herbal products will be described. The strengths and weaknesses of the various techniques available will be addressed. Limitations of the other approaches including morphological or microscopic analysis and DNA-based analysis will be presented.