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Varela K, Yoshimoto FK. Syntheses of deuterium-labeled dihydroartemisinic acid (DHAA) isotopologues and mechanistic studies focused on elucidating the conversion of DHAA to artemisinin. Org Biomol Chem 2024. [PMID: 39158554 DOI: 10.1039/d4ob00777h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/20/2024]
Abstract
Dihydroartemisinic acid (DHAA), a sesquiterpenoid natural product from Artemisia annua, converts to artemisinin, an anti-malarial natural product that contains an endoperoxide bridge. The endoperoxide moiety is responsible for the biological activity of artemisinin. Therefore, understanding the biosynthesis of this functional group could lead to the optimization of the process to produce this medicine. DHAA converts to artemisinin through the incorporation of two molecules of oxygen in a four-step process. The reaction is a spontaneous cascade process that involves (i) the initial incorporation of a molecule of oxygen through the reaction of an allylic C-H bond of DHAA, (ii) followed by the cleavage of a C-C bond, (iii) the incorporation of a second molecule of oxygen, and (iv) polycyclization to yield artemisinin. This manuscript is focused on describing the chemical syntheses of regioselectively polydeuterated DHAA isotopologues at C3 and C15, in addition to research efforts related to clarifying how the endoperoxide-forming process of artemisinin occurs.
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Affiliation(s)
- Kaitlyn Varela
- Department of Chemistry, The University of Texas San Antonio (UTSA), One UTSA Circle, San Antonio, TX 78249-0698, USA.
| | - Francis K Yoshimoto
- Department of Chemistry, The University of Texas San Antonio (UTSA), One UTSA Circle, San Antonio, TX 78249-0698, USA.
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Asmaey MA, Hamed A, Shaaban M. Natural Peroxides from Plants: Historical Discovery, Biosynthesis, and Biological Activities. Chem Biodivers 2024:e202400644. [PMID: 38958342 DOI: 10.1002/cbdv.202400644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 07/01/2024] [Accepted: 07/03/2024] [Indexed: 07/04/2024]
Abstract
Naturally occurring peroxides received great interest and attention from scientific research groups worldwide due to their structural diversity, versatile biological activities, and pharmaceutical properties. In the present review, we describe the historical discovery of natural peroxides from plants systematically and update the researchers with recently explored ones justifying their structural caterogrization and biological/pharmaceutical properties intensively. Till the end of 2023, 192 peroxy natural products from plants were documented herein for the first time implying most categories of natural scaffolds (e. g. terpenes, polyketides, phenolics and alkaloids). Numerically, the reported plants' peroxides have been classified into seventy-four hydro-peroxides, hundred seven endo-peroxides and eleven acyl-peroxides. Endo-peroxides (cyclic alkyl peroxides) are an important group due to their high variety of structural frameworks, and we have further divided them into "four-, five-, six and seven"-membered rings. Biosynthetically, a shedding light on the intricate mechanisms behind the formation of plant-derived peroxides are addressed as well.
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Affiliation(s)
- Mostafa A Asmaey
- Department of Chemistry, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut, 71524, Egypt
| | - Abdelaaty Hamed
- Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City-Cairo, 11884, Egypt
| | - Mohamed Shaaban
- Chemistry of Natural Compounds Department, Pharmaceutical and Drug Industries Research Institute, National Research Centre, El-Buhouth St. 33, Dokki-Cairo, 12622, Egypt
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Zhou L, Yang LS, Wang L, Liu HD, Gao M, Chen FJ, Yang J, Li QJ, Yang XS. Cinnamigones A-C, three highly oxidized guaiane-type sesquiterpenes with neuroprotective activity from Cinnamomum migao. PHYTOCHEMISTRY 2023; 212:113728. [PMID: 37211335 DOI: 10.1016/j.phytochem.2023.113728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/11/2023] [Accepted: 05/15/2023] [Indexed: 05/23/2023]
Abstract
Cinnamigones A-C, three undescribed highly oxidized guaiane-type sesquiterpenes were isolated from the fruits of Cinnamomum migao. Cinnamigone A (1), structurally artemisinin-like, is a natural 1,2,4-trioxane caged endoperoxide with an unprecedented tetracyclic 6/6/7/5 ring system. Compounds 2-3 are classic guaiane sesquiterpene featuring different epoxy units. Guaiol (4) is considered to be the precursor of 1-3 in the biosynthesis pathway hypothesis. The planar structures and configurations of cinnamigones A-C were elucidated by spectral analysis, HRESIMS, X-ray crystallography and ECD calculations. Evaluation of the neuroprotective activity of 1-3 on N-methyl-ᴅaspartate (NMDA) toxicity was demonstrated that compounds 1-2 exhibited moderate neuroprotective activity against NMDA-induced neurotoxicity.
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Affiliation(s)
- Lang Zhou
- School of Basic Medicine / State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, China; Engineering Research Center of Natural Product Efficient Utilization in Guizhou, Natural Products Research Center of Guizhou Province, Guiyang 550014, China
| | - Li-Shou Yang
- School of Basic Medicine / State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, China; Engineering Research Center of Natural Product Efficient Utilization in Guizhou, Natural Products Research Center of Guizhou Province, Guiyang 550014, China
| | - Li Wang
- Engineering Research Center of Natural Product Efficient Utilization in Guizhou, Natural Products Research Center of Guizhou Province, Guiyang 550014, China
| | - Hua-Dan Liu
- Engineering Research Center of Natural Product Efficient Utilization in Guizhou, Natural Products Research Center of Guizhou Province, Guiyang 550014, China
| | - Ming Gao
- Engineering Research Center of Natural Product Efficient Utilization in Guizhou, Natural Products Research Center of Guizhou Province, Guiyang 550014, China
| | - Fa-Ju Chen
- School of Basic Medicine / State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, China; Engineering Research Center of Natural Product Efficient Utilization in Guizhou, Natural Products Research Center of Guizhou Province, Guiyang 550014, China
| | - Juan Yang
- Engineering Research Center of Natural Product Efficient Utilization in Guizhou, Natural Products Research Center of Guizhou Province, Guiyang 550014, China
| | - Qi-Ji Li
- School of Basic Medicine / State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, China; Engineering Research Center of Natural Product Efficient Utilization in Guizhou, Natural Products Research Center of Guizhou Province, Guiyang 550014, China.
| | - Xiao-Sheng Yang
- School of Basic Medicine / State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, China; Engineering Research Center of Natural Product Efficient Utilization in Guizhou, Natural Products Research Center of Guizhou Province, Guiyang 550014, China.
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Varela K, Al Mahmud H, Arman HD, Martinez LR, Wakeman CA, Yoshimoto FK. Autoxidation of a C2-Olefinated Dihydroartemisinic Acid Analogue to Form an Aromatic Ring: Application to Serrulatene Biosynthesis. JOURNAL OF NATURAL PRODUCTS 2022; 85:951-962. [PMID: 35357832 PMCID: PMC9035337 DOI: 10.1021/acs.jnatprod.1c01101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Dihydroartemisinic acid (DHAA) is a plant natural product that undergoes a spontaneous endoperoxide-forming cascade reaction to yield artemisinin in the presence of air. The endoperoxide functional group gives artemisinin its biological activity that kills Plasmodium falciparum, the parasite that causes malaria. To enhance our understanding of the mechanism of this cascade reaction, 2,3-didehydrodihydroartemisinic acid (2,3-didehydro-DHAA), a DHAA derivative with a double bond at the C2-position, was synthesized. When 2,3-didehydro-DHAA was exposed to air over time, instead of forming an endoperoxide, this compound predominantly underwent aromatization. This olefinated DHAA analogue reveals the requirement of a monoalkene functional group to initiate the endoperoxide-forming cascade reaction to yield artemisinin from DHAA. In addition, this aromatization process was exploited to illustrate the autoxidation process of a different plant natural product, dihydroserrulatene, to form the aromatic ring in serrulatene. This spontaneous aromatization process has applications in other natural products such as leubethanol and erogorgiaene. Due to their similarity in structure to antimicrobial natural products, the synthesized compounds in this study were tested for biological activity. A group of the tested compounds had minimum inhibitory concentration (MIC) values ranging from 12.5 to 25 μg/mL against the bacterial pathogen Staphylococcus aureus and the fungal pathogen Cryptococcus neoformans.
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Affiliation(s)
- Kaitlyn Varela
- Department of Chemistry, The University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Hafij Al Mahmud
- Biological Sciences, Texas Tech University, Lubbock, Texas 79409, United States
| | - Hadi D Arman
- Department of Chemistry, The University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Luis R Martinez
- Department of Oral Biology, University of Florida College of Dentistry, Center for Immunology and Transplantation, Center for Translational Research in Neurodegenerative Disease, and The Emerging Pathogens Institute, Gainesville, Florida 32610, United States
| | - Catherine A Wakeman
- Biological Sciences, Texas Tech University, Lubbock, Texas 79409, United States
| | - Francis K Yoshimoto
- Department of Chemistry, The University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
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Varela K, Arman HD, Yoshimoto FK. Synthesis of [15,15,15- 2H 3]-Dihydroartemisinic Acid and Isotope Studies Support a Mixed Mechanism in the Endoperoxide Formation to Artemisinin. JOURNAL OF NATURAL PRODUCTS 2021; 84:1967-1984. [PMID: 34137611 DOI: 10.1021/acs.jnatprod.1c00246] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Artemisinin is the plant natural product used to treat malaria. The endoperoxide bridge of artemisinin confers its antiparasitic properties. Dihydroartemisinic acid is the biosynthetic precursor of artemisinin that was previously shown to nonenzymatically undergo endoperoxide formation to yield artemisinin. This report discloses the synthesis of [15,15,15-2H3]-dihydroartemisinic acid and its use to determine the mechanism of endoperoxide formation. Several new observations were made: (i) Ultraviolet-C (UV-C) radiation initially accelerates artemisinin formation and subsequently promotes homolytic cleavage of the O-O bond and rearrangement of artemisinin to a different product, and (ii) dideuterated and trideuterated dihydroartemisinic acid isotopologues at C3 and C15 converted to artemisinin at a slower rate compared to nondeuterated dihydroartemisinic acid, revealing a kinetic isotope effect in the initial ene reaction toward endoperoxide formation (kH/kD ∼ 2-3). (iii) The rate of conversion from dihydroartemisinic acid to artemisinin increased with the amount of dihydroartemisinic acid, suggesting an intermolecular interaction to promote endoperoxide formation, and (iv) 18O2-labeling showed incorporation of three and four oxygen atoms from molecular oxygen into the endoperoxide bridge of artemisinin. These results reveal new insights toward understanding the mechanism of endoperoxide formation in artemisinin biosynthesis.
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Affiliation(s)
- Kaitlyn Varela
- Department of Chemistry, The University of Texas at San Antonio (UTSA), San Antonio, Texas 78249-0698, United States
| | - Hadi D Arman
- Department of Chemistry, The University of Texas at San Antonio (UTSA), San Antonio, Texas 78249-0698, United States
| | - Francis K Yoshimoto
- Department of Chemistry, The University of Texas at San Antonio (UTSA), San Antonio, Texas 78249-0698, United States
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Khanal P. Antimalarial and anticancer properties of artesunate and other artemisinins: current development. MONATSHEFTE FUR CHEMIE 2021; 152:387-400. [PMID: 33814617 PMCID: PMC8008344 DOI: 10.1007/s00706-021-02759-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/22/2021] [Indexed: 02/06/2023]
Abstract
This review provides a recent perspective of artesunate and other artemisinins as antimalarial drugs and their uses in cancer therapy. Artesunate is an artemisinin derivative. Artemisinin is extracted from the plant Artemisia annua. Artemisinin and its derivatives have been the most useful drug for malarial treatment in human history. The artesunate has an advantage of a hydrophilic group over other artemisinins which makes it a more potent drug. On the industrial scale, artemisinins are synthesized in semisynthetic ways. The 1,2,4-endoperoxide bridge of artemisinins is responsible for the drug's antimalarial activity. There is the emergence of artemisinin resistance on Plasmodium falciparum and pieces of evidence suggest that it is mainly due to the mutation at Kelch13 protein of P. falciparum. Clinical trial data show that the artesunate is more favorable than quinine and other artemisinins to treat patients with severe malaria. Pieces of evidence indicate that artemisinins can be developed as anticancer drugs. The mechanism of actions on how artemisinins act as an anticancer drug involves oxidative stress, DNA damage and repair, and various types of cell deaths. GRAPHIC ABSTRACT
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Affiliation(s)
- Pitambar Khanal
- Nagarik College, Tribhuvan University, Gaidakot-2, Nawalparasi Purva, Gandaki, Nepal
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