scholarly journals Recent Developments in the Functionalization of Betulinic Acid and Its Natural Analogues: A Route to New Bioactive Compounds

Molecules ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 355 ◽  
Author(s):  
Joana L. C. Sousa ◽  
Carmen S. R. Freire ◽  
Armando J. D. Silvestre ◽  
Artur M. S. Silva
Keyword(s):  
Betulinic Acid ◽  
Antitumor Agents ◽  
Aldol Condensation ◽  
Antimalarial Activity ◽  
Biological Activities ◽  
Chemical Transformations ◽  
Pentacyclic Triterpenoids ◽  
Natural Analogues ◽  
Palladium Catalyzed ◽  
Aldol Condensation Reactions

Betulinic acid (BA) and its natural analogues betulin (BN), betulonic (BoA), and 23-hydroxybetulinic (HBA) acids are lupane-type pentacyclic triterpenoids. They are present in many plants and display important biological activities. This review focuses on the chemical transformations used to functionalize BA/BN/BoA/HBA in order to obtain new derivatives with improved biological activity, covering the period since 2013 to 2018. It is divided by the main chemical transformations reported in the literature, including amination, esterification, alkylation, sulfonation, copper(I)-catalyzed alkyne-azide cycloaddition, palladium-catalyzed cross-coupling, hydroxylation, and aldol condensation reactions. In addition, the synthesis of heterocycle-fused BA/HBA derivatives and polymer‒BA conjugates are also addressed. The new derivatives are mainly used as antitumor agents, but there are other biological applications such as antimalarial activity, drug delivery, bioimaging, among others.

Recent advancement and novel application of organocatalyzed aldol condensation reactions: A comprehensive review

2022 ◽  
Vol 19 ◽  
Author(s):  
Ajay Kumar Verma ◽  
Braj Nandan Kishor ◽  
Om Prakash
Keyword(s):  
Amino Acids ◽  
Aldol Condensation ◽  
Biological Activities ◽  
Condensation Reaction ◽  
Addition Product ◽  
Aldol Reactions ◽  
Hydroxy Ketone ◽  
Unsaturated Ketone ◽  
Condensation Reactions ◽  
Aldol Condensation Reactions

Background: Aldol reactions play an important role in the development of organic synthesis-owing to their critical importance for the forming of carbon-carbon bonds while concurrently one or two chiral centers come into being. In the modern scenario, the Aldol condensation reaction has arisen as perhaps the most significant reaction for the formation of novel medicinal agents exhibits promising pharmacological activities. Objective: The purpose of this study is to present newer synthetic approaches through Aldol condensation reaction for the synthesis of diverse scaffolds to explore the promising various types of biological activities. Methods: Aldol condensation concerns the nucleophilic addition reaction of a ketone enolate to an aldehyde to form aldol or β- hydroxy ketone. Occasionally, the aldol addition product losing water molecule yields an α, β-unsaturated ketone. Results: Results showed that amino acids and all lengths of peptides are utilized as chiral catalysts. As of now, the arrangement of catalysts that have been accounted for is intensely one-sided towards proline. This is to some degree because of its exceptional status among the normally happening amino acids as an auxiliary amine and to its restricted underlying adaptability. Conclusion: The present study thus provides useful insight concerning the promising coherent way for the synthesis of prolinamide analogue of proline, through a direct asymmetric aldol condensation reaction. Thus, the current study summarizes various Aldol condensation reactions for the synthesis of novel agents as well as their promising pharmacological importance.

scholarly journals Functionalization of Betulinic Acid with Polyphenolic Fragments for the Development of New Amphiphilic Antioxidants

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 148
Author(s):  
Joana L. C. Sousa ◽  
Cristiana Gonçalves ◽  
Ricardo M. Ferreira ◽  
Susana M. Cardoso ◽  
Carmen S. R. Freire ◽  
...  
Keyword(s):  
Betulinic Acid ◽  
Aldol Condensation ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Added Value ◽  
Scavenging Effect ◽  
Synthetic Strategy ◽  
Antioxidant Agents ◽  
Radical Scavenging Ability ◽  
Aldol Condensation Reactions

The present work aimed at the valorization of biomass derived compounds by their transformation into new added-value compounds with enhanced antioxidant properties. In this context, betulinic acid (BA) was decorated with polyphenolic fragments, and polyhydroxylated (E)-2-benzylidene-19,28-epoxyoleanane-3,28-diones 4a–d were obtained. For that, the synthetic strategy relied on base-promoted aldol condensation reactions of methyl betulonate, which was previously prepared from natural BA, with appropriate benzaldehydes, followed by cleavage of the methyl protecting groups with BBr3. It is noteworthy that the HBr release during the work-up of the cleavage reactions led to the rearrangement of the lupane-type skeleton of the expected betulonic acid derivatives into oleanane-type compounds 4a–d. The synthesized compounds 4a–d were designed to have specific substitution patterns at C-2 of the triterpene scaffold, allowing the establishment of a structure-activity relationship. The radical scavenging ability of 4a–d was evaluated using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS•+) scavenging assays. In particular, derivative 4c, bearing a catechol unit, revealed to be the most efficient scavenger against both free radicals DPPH• and ABTS•+. Subsequently, we designed two analogues of the hit derivative 4c in order to achieve more potent antioxidant agents: (i) the first analogue carries an additional unsaturation in its lateral chain at C-2 (analogue 5) and (ii) in the second analogue, E-ring was kept in its open form (analogue 6). It was observed that the presence of an extended π-conjugated system at C-2 contributed to an increased scavenging effect, since analogue 5 was more active than 6, α-tocopherol, and 4c in the ABTS•+ assay.

An Overview on Steroids and Microwave Energy in Multi-Component Reactions towards the Synthesis of Novel Hybrid Molecules

2020 ◽  
Vol 17 (8) ◽  
pp. 594-609
Author(s):  
Preetismita Borah ◽  
Vhatkar Dattatraya Shivling ◽  
Bimal Krishna Banik ◽  
Biswa Mohan Sahoo
Keyword(s):  
Energy Consumption ◽  
Multicomponent Reactions ◽  
Biological Activities ◽  
Vital Role ◽  
Microwave Energy ◽  
Biosynthetic Pathways ◽  
Chemical Transformations ◽  
Carbon Carbon Bond ◽  
Hybrid Molecules ◽  
Time Required

In recent years, hybrid systems are gaining considerable attention owing to their various biological applications in drug development. Generally, hybrid molecules are constructed from different molecular entities to generate a new functional molecule with improved biological activities. There already exist a large number of naturally occurring hybrid molecules based on both non-steroid and steroid frameworks synthesized by nature through mixed biosynthetic pathways such as, a) integration of the different biosynthetic pathways or b) Carbon- Carbon bond formation between different components derived through different biosynthetic pathways. Multicomponent reactions are a great way to generate efficient libraries of hybrid compounds with high diversity. Throughout the scientific history, the most common factors developing technologies are less energy consumption and avoiding the use of hazardous reagents. In this case, microwave energy plays a vital role in chemical transformations since it involves two very essential criteria of synthesis, minimizing energy consumption required for heating and time required for the reaction. This review summarizes the use of microwave energy in the synthesis of steroidal and non-steroidal hybrid molecules and the use of multicomponent reactions.

Biotransformation of Coumarins by Filamentous Fungi: An Alternative Way for Achievement of Bioactive Analogs

2019 ◽  
Vol 16 (6) ◽  
pp. 568-577 ◽  
Author(s):  
Jainara Santos do Nascimento ◽  
João Carlos Silva Conceição ◽  
Eliane de Oliveira Silva
Keyword(s):  
Filamentous Fungi ◽  
Chemical Reactions ◽  
Biological Activities ◽  
Chemical Transformations ◽  
Chemical Structures ◽  
Pattern Structures ◽  
Pharmacological Interest ◽  
Aspergillus Sp ◽  
The Impact ◽  
Related Compounds

Coumarins are natural 1,2-benzopyrones, present in remarkable amounts as secondary metabolites in edible and medicinal plants. The low yield in the coumarins isolation from natural sources, along with the difficulties faced by the total synthesis, make them attractive for biotechnological studies. The current literature contains several reports on the biotransformation of coumarins by fungi, which can generate chemical analogs with high selectivity, using mild and eco-friendly conditions. Prompted by the enormous pharmacological interest in the coumarin-related compounds, their alimentary and chemical applications, this review covers the biotransformation of coumarins by filamentous fungi. The chemical structures of the analogs were presented and compared with those from the pattern structures. The main chemical reactions catalyzed the insertion of functional groups, and the impact on the biological activities caused by the chemical transformations were discussed. Several chemical reactions can be catalyzed by filamentous fungi in the coumarin scores, mainly lactone ring opening, C3-C4 reduction and hydroxylation. Chunninghamella sp. and Aspergillus sp. are the most common fungi used in these transformations. Concerning the substrates, the biotransformation of pyranocoumarins is a rarer process. Sometimes, the bioactivities were improved by the chemical modifications and coincidences with the mammalian metabolism were pointed out.

A Review of Electroporation-based Antitumor Skin Therapies and Investigation of Betulinic Acid-loaded Ointment

2018 ◽  
Vol 18 (5) ◽  
pp. 693-701
Author(s):  
Monika Bakonyi ◽  
Szilvia Berko ◽  
Gabor Eros ◽  
Gabor Varju ◽  
Cristina A. Dehelean ◽  
...  
Keyword(s):  
Betulinic Acid ◽  
High Efficiency ◽  
Antitumor Agents ◽  
Ex Vivo ◽  
Mouse Skin ◽  
Chemotherapeutic Agents ◽  
Hairless Mouse ◽  
Promising Tool ◽  
Acid Formulation ◽  
Invasive Method

Background: Electrochemotherapy is a novel treatment for cutaneous and subcutaneous tumors utilizing the combination of electroporation and chemotherapeutic agents. Since tumors have an increasing incidence nowadays as a result of environmental and genetic factors, electrochemotherapy could be a promising treatment for cancer patients. Objective: The aim of this article is to summarize the novel knowledge about the use of electroporation for antitumor treatments and to present a new application of electrochemotherapy with a well-known plant derived antitumor drug betulinic acid. For the review we have searched the databases of scientific and medical research to collect the available publications about the use of electrochemotherapy in the treatment of various types of cancer. Method: By the utilization of the available knowledge, we investigated the effect of electroporation on the penetration of a topically applied betulinic acid formulation into the skin by ex vivo Raman spectroscopy on hairless mouse skin. Results: Raman measurements have demonstrated that the penetration depth of betulinic acid can be remarkably ameliorated by the use of electroporation, so this protocol can be a possibility for the treatment of deeper localized cancer nodules. Furthermore, it proved the influence of various treatment times, since they caused different spatial distributions of the drug in the skin. Conclusion: The review demonstrates that electrochemotherapy is a promising tool to treat different kinds of tumors with high efficiency and with only a few moderate adverse effects. Moreover, it presents a non-invasive method to enhance the penetration of antitumor agents, which can offer novel prospects for antitumor therapies.

Secondary Metabolites of Plant Origin containing Carbazole as Lead Molecule: A Review

2019 ◽  
Vol 05 ◽  
Author(s):  
Atul Sharma ◽  
Devender Pathak
Keyword(s):  
Drug Discovery ◽  
Heterocyclic Compounds ◽  
Biological Activities ◽  
Chemical Compounds ◽  
Lethal Effect ◽  
Chemical Diversity ◽  
Chemical Transformations ◽  
Pharmacological Effects ◽  
Structural Class ◽  
Biological Targets

Keeping this fact that study of a body is biology but life is all about chemicals and chemical transformations, many medicinal chemist start research in finding new and novel chemical compounds which having pharmacological activities. Most of those chemical compounds which are having active pharmacological effects are heterocyclic compounds. Heterocyclic compounds clutch a particular place among pharmaceutically active natural and synthetic compounds. The ability to serve both as biomimetics and reactive pharmacophores of heterocyclic nuclei is incredible and it has principally contributed to their unique value as traditional key elements of numerous drugs. These heterocyclic nuclei offer a huge area for new lead molecules for drug discovery and for generation of activity relationships with biological targets to enhance pharmacological effects. For these reasons, it is not surprising that this structural class has received special attention in drug discovery. The hydrogen bond acceptors and donors arranged in a manner of a semi-rigid skeleton in heterocyclic rings and therefore they can present a varied display of significant pharmacophores. Lead identification and optimization of drug target probable can be achieved by generation of chemical diversity produced by derivatization of heterocyclic pharmacophores with different groups or substituents. A tricyclic carbazole nucleus is an integral part of naturally occurring alkaloids and synthetic derivatives, possessing various potential biological activities such as anticancer, antimicrobial and antiviral. Binding mechanism of carbazole with target receptor as a molecule or fused molecule exhibits the potential lethal effect.

scholarly journals Nanoformulations for Delivery of Pentacyclic Triterpenoids in Anticancer Therapies

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1764
Author(s):  
Anna Kaps ◽  
Paweł Gwiazdoń ◽  
Ewa Chodurek
Keyword(s):  
Water Solubility ◽  
Biological Activities ◽  
Premature Mortality ◽  
Delivery Systems ◽  
Pentacyclic Triterpenoids ◽  
Anticancer Properties ◽  
Oncological Patients ◽  
Antitumor Potential ◽  
Ring Structures

The search for safe and effective anticancer therapies is one of the major challenges of the 21st century. The ineffective treatment of cancers, classified as civilization diseases, contributes to a decreased quality of life, health loss, and premature mortality in oncological patients. Many natural phytochemicals have anticancer potential. Pentacyclic triterpenoids, characterized by six- and five-membered ring structures, are one of the largest class of natural metabolites sourced from the plant kingdom. Among the known natural triterpenoids, we can distinguish lupane-, oleanane-, and ursane-types. Pentacyclic triterpenoids are known to have many biological activities, e.g., anti-inflammatory, antibacterial, hepatoprotective, immunomodulatory, antioxidant, and anticancer properties. Unfortunately, they are also characterized by poor water solubility and, hence, low bioavailability. These pharmacological properties may be improved by both introducing some modifications to their native structures and developing novel delivery systems based on the latest nanotechnological achievements. The development of nanocarrier-delivery systems is aimed at increasing the transport capacity of bioactive compounds by enhancing their solubility, bioavailability, stability in vivo and ensuring tumor-targeting while their toxicity and risk of side effects are significantly reduced. Nanocarriers may vary in sizes, constituents, shapes, and surface properties, all of which affect the ultimate efficacy and safety of a given anticancer therapy, as presented in this review. The presented results demonstrate the high antitumor potential of systems for delivery of pentacyclic triterpenoids.

Epoxides, Cyclic Sulfites, and Sulfate from Natural Pentacyclic Triterpenoids:  Theoretical Calculations and Chemical Transformations

2003 ◽  
Vol 68 (12) ◽  
pp. 4833-4844 ◽  
Author(s):  
Andrés García-Granados ◽  
Pilar E. López ◽  
Enrique Melguizo ◽  
Juan N. Moliz ◽  
Andrés Parra ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Chemical Transformations ◽  
Pentacyclic Triterpenoids ◽  
Cyclic Sulfites
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