scholarly journals Diversity in Chemical Structures and Biological Properties of Plant Alkaloids

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3374
Author(s):  
Sweta Bhambhani ◽  
Kirtikumar R. Kondhare ◽  
Ashok P. Giri

Phytochemicals belonging to the group of alkaloids are signature specialized metabolites endowed with countless biological activities. Plants are armored with these naturally produced nitrogenous compounds to combat numerous challenging environmental stress conditions. Traditional and modern healthcare systems have harnessed the potential of these organic compounds for the treatment of many ailments. Various chemical entities (functional groups) attached to the central moiety are responsible for their diverse range of biological properties. The development of the characterization of these plant metabolites and the enzymes involved in their biosynthesis is of an utmost priority to deliver enhanced advantages in terms of biological properties and productivity. Further, the incorporation of whole/partial metabolic pathways in the heterologous system and/or the overexpression of biosynthetic steps in homologous systems have both become alternative and lucrative methods over chemical synthesis in recent times. Moreover, in-depth research on alkaloid biosynthetic pathways has revealed numerous chemical modifications that occur during alkaloidal conversions. These chemical reactions involve glycosylation, acylation, reduction, oxidation, and methylation steps, and they are usually responsible for conferring the biological activities possessed by alkaloids. In this review, we aim to discuss the alkaloidal group of plant specialized metabolites and their brief classification covering major categories. We also emphasize the diversity in the basic structures of plant alkaloids arising through enzymatically catalyzed structural modifications in certain plant species, as well as their emerging diverse biological activities. The role of alkaloids in plant defense and their mechanisms of action are also briefly discussed. Moreover, the commercial utilization of plant alkaloids in the marketplace displaying various applications has been enumerated.

1991 ◽  
Vol 56 (10) ◽  
pp. 2209-2217 ◽  
Author(s):  
Jan Hlaváček ◽  
Jana Pírková ◽  
Jan Pospíšek ◽  
Jiřina Slaninová ◽  
Lenka Maletínská

Using solution or solid-phase synthesis we prepared the cholecystokinin fragment Boc-CCK-7 (Boc-Tyr-(SO3-.Na+)-Met-Gly-Trp-Met-Asp-PheNH2) and its four analogues in which the methionine moiety (Met) in the carboxy-terminal part is replaced by tert-leucine (Tle) or neopentylglycine (Neo) residue or D-enantiomers of these non-coded amino acids. These structural modifications led to reduction of the studied biological activities (gall bladder contraction, anorectic activity, analgetic and sedation activity) of all prepared analogues except Boc[Neo5]-CCK-7 which, being less analgetically active, retains full gall bladder and sedation activity of CCK-8. Moreover, its anorectic activity is substantially higher (400%). This analogue is very interesting particularly for its selectively increased (4x) anorectic effect compared with that of CCK-8.


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4445
Author(s):  
Tiphaine Wong ◽  
Lorette Brault ◽  
Eric Gasparotto ◽  
Romuald Vallée ◽  
Pierre-Yves Morvan ◽  
...  

Marine polysaccharides are part of the huge seaweeds resources and present many applications for several industries. In order to widen their potential as additives or bioactive compounds, some structural modifications have been studied. Among them, simple hydrophobization reactions have been developed in order to yield to grafted polysaccharides bearing acyl-, aryl-, alkyl-, and alkenyl-groups or fatty acid chains. The resulting polymers are able to present modified physicochemical and/or biological properties of interest in the current pharmaceutical, cosmetics, or food fields. This review covers the chemical structures of the main marine polysaccharides, and then focuses on their structural modifications, and especially on hydrophobization reactions mainly esterification, acylation, alkylation, amidation, or even cross-linking reaction on native hydroxyl-, amine, or carboxylic acid functions. Finally, the question of the necessary requirement for more sustainable processes around these structural modulations of marine polysaccharides is addressed, considering the development of greener technologies applied to traditional polysaccharides.


2021 ◽  
Vol 14 (12) ◽  
pp. 1274
Author(s):  
Jinyun Chen ◽  
Sunyan Lv ◽  
Jia Liu ◽  
Yanlei Yu ◽  
Hong Wang ◽  
...  

1,3-Oxazole chemicals are a unique class of five-membered monocyclic heteroarenes, containing a nitrogen atom and an oxygen. These alkaloids have attracted extensive attention from medicinal chemists and pharmacologists owing to their diverse arrays of chemical structures and biological activities, and a series of 1,3-oxazole derivatives has been developed into therapeutic agents (e.g., almoxatone, befloxatone, cabotegravir, delpazolid, fenpipalone, haloxazolam, inavolisib). A growing amount of evidence indicates that marine organisms are one of important sources of 1,3-oxazole-containing alkaloids. To improve our knowledge regarding these marine-derived substances, as many as 285 compounds are summarized in this review, which, for the first time, highlights their sources, structural features and biological properties, as well as their biosynthesis and chemical synthesis. Perspective for the future discovery of new 1,3-oxazole compounds from marine organisms is also provided.


2021 ◽  
Vol 75 (6) ◽  
pp. 543-547
Author(s):  
Florian Hubrich ◽  
Alessandro Lotti ◽  
Thomas A. Scott ◽  
Jörn Piel

Nature has evolved a remarkable array of biosynthetic enzymes that install diverse chemistries into natural products (NPs), bestowing them with a range of important biological properties that are of considerable therapeutic value. This is epitomized by the ribosomally synthesized and post-translationally modified peptides (RiPPs), a class of peptide natural products that undergo extensive post-translational modifications to produce structurally diverse bioactive peptides. In this review, we provide an overview of our research into the proteusin RiPP family, describing characterized members and the maturation enzymes responsible for their unique chemical structures and biological activities. The diverse enzymology identified in the first two proteusin pathways highlights the enormous potential of the RiPP class for new lead structures and novel pharmacophore-installing maturases as biocatalytic tools for drug discovery efforts.


Author(s):  
Keisham S. Singh ◽  
Supriya Tilvi

: The marine sponges of the genus Oceanapia sp. is comprised of more than 50 species and are distributed in the seas around the tropical and subtropical regions. They are mainly found in the northern Indian oceans, Japan, and the south pacific coast. They are highly colored and known to be a rich source of various secondary metabolites, particularly, alkaloids. Several other secondary metabolites were also reported from this genus which include terpenes, sphingolipids, ceramides, cerebrosides, acetylenic acids, and thiocyanatins, etc. Many of these compounds isolated from this genus exhibited various biological properties including anticancer, antimicrobial, anti-HIV, ichthyotoxicity and nematocidal activities. Although several secondary metabolites have been reported from this genus, a dedicated review of the chemicals and biological activities of this genus is so far lacking. Keeping this in mind this review describes the various chemical entities isolated from the sponges of the genus Oceanapia detailing their chemical structures along with their reported biological properties.


Author(s):  
Shaochen Li ◽  
Min Lv ◽  
Shaoyong Zhang ◽  
Hui Xu

: Derivatives of monosaccharides and oligosaccharides play the important roles in biological processes. Monosaccharides are the single carbohydrate building blocks, such as glucose, xylose, and fructose. Oligosaccharides are composed of 2–10 monosaccharides including disaccharides and trisaccharides. Moreover, monosaccharides, oligosaccharides and their derivatives are vital molecules with various biological properties including anticancer activity, antiviral activity, insecticidal activity, antimicrobial activity, and antioxidant activity. This review covers a survey of structural modifications, biological activities, and mechanisms of action of monosaccharides, oligosaccharides and their derivatives. Additionally, their structure–activity relationships are also concluded.


2020 ◽  
Vol 20 (16) ◽  
pp. 1633-1652
Author(s):  
Meng Hao ◽  
Min Lv ◽  
Hui Xu

Andrographolide, a labdane diterpenoid, is extracted and isolated from the plants of Andrographis paniculata. Andrographolide and its derivatives exhibited a wide range of biological properties, including anticancer activity, antibacterial activity, hepatoprotective activity, antiinflammatory activity, antiviral activity, antimalarial activity, antidiabetic activity, insecticidal activity, etc. As a continuation, this review aims at giving an overview of the recent advances (from 2015 to 2018) of andrographolide and its derivatives with regard to bioactivities, mechanisms of action, structural modifications, and structure-activity relationships.


Planta Medica ◽  
2020 ◽  
Author(s):  
Hakmin Mun ◽  
Helen E. Townley

AbstractPlant volatile organic compounds (volatiles) are secondary plant metabolites that play crucial roles in the reproduction, defence, and interactions with other vegetation. They have been shown to exhibit a broad range of biological properties and have been investigated for antimicrobial and anticancer activities. In addition, they are thought be more environmentally friendly than many other synthetic chemicals 1. Despite these facts, their applications in the medical, food, and agricultural fields are considerably restricted due to their volatilities, instabilities, and aqueous insolubilities. Nanoparticle encapsulation of plant volatile organic compounds is regarded as one of the best strategies that could lead to the enhancement of the bioavailability and biological activity of the volatile compounds by overcoming their physical limitations and promoting their controlled release and cellular absorption. In this review, we will discuss the biosynthesis and analysis of plant volatile organic compounds, their biological activities, and limitations. Furthermore, different types of nanoparticle platforms used to encapsulate the volatiles and the biological efficacies of nanoencapsulated volatile organic compounds will be covered.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Ye Wang ◽  
Hongping Hou ◽  
Qiang Ren ◽  
Haoyu Hu ◽  
Tiechui Yang ◽  
...  

AbstractFritillaria naturally grows in the temperate region of Northern Hemisphere and mainly distributes in Central Asia, Mediterranean region, and North America. The dried bulbs from a dozen species of this genus have been usually used as herbal medicine, named Beimu in China. Beimu had rich sources of phytochemicals and have extensively applied to respiratory diseases including coronavirus disease (COVID-19). Fritillaria species have alkaloids that act as the main active components that contribute multiple biological activities, including anti-tussive, expectorant, and anti-asthmatic effects, especially against certain respiratory diseases. Other compounds (terpenoids, steroidal saponins, and phenylpropanoids) have also been identified in species of Fritillaria. In this review, readers will discover a brief summary of traditional uses and a comprehensive description of the chemical profiles, biological properties, and analytical techniques used for quality control. In general, the detailed summary reveals 293 specialized metabolites that have been isolated and analyzed in Fritillaria species. This review may provide a scientific basis for the chemical ecology and metabolomics in which compound identification of certain species remains a limiting step.


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2754
Author(s):  
Cong Wang ◽  
Weisheng Du ◽  
Huanyun Lu ◽  
Jianzhou Lan ◽  
Kailin Liang ◽  
...  

Marine actinomycetes, Streptomyces species, produce a variety of halogenated compounds with diverse structures and a range of biological activities owing to their unique metabolic pathways. These halogenated compounds could be classified as polyketides, alkaloids (nitrogen-containing compounds) and terpenoids. Halogenated compounds from marine actinomycetes possess important biological properties such as antibacterial and anticancer activities. This review reports the sources, chemical structures and biological activities of 127 new halogenated compounds originated mainly from Streptomyces reported from 1992 to 2020.


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