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Jing SX, McDermott CM, Flanders PL, Reis-Havlat M, Chen SN, Bedran-Russo AK, McAlpine JB, Ambrose EA, Pauli GF. Chemical Transformation of B- to A-type Proanthocyanidins and 3D Structural Implications. JOURNAL OF NATURAL PRODUCTS 2024; 87:1416-1425. [PMID: 38687902 DOI: 10.1021/acs.jnatprod.4c00231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
In nature, proanthocyanidins (PACs) with A-type linkages are relatively rare, likely due to biosynthetic constraints in the formation of additional ether bonds to be introduced into the more common B-type precursors. However, A-type linkages confer greater structural rigidity on PACs than do B-type linkages. Prior investigations into the structure-activity relationships (SAR) describing how plant-derived PACs with B- and complex AB-type linkages affect their capacity for dentin biomodification indicate that a higher ratio of double linkages leads to a greater interaction with dentin type I collagen. Thus, A-type PACs emerge as particularly intriguing candidates for interventional functional biomaterials. This study employed a free-radical-mediated oxidation using DPPH to transform trimeric and tetrameric B-type PACs, 2 and 4, respectively, into their exclusively A-type linked analogues, 3 and 5, respectively. The structures and absolute configurations of the semisynthetic products, including the new all-A-type tetramer 5, were determined by comprehensive spectroscopic analysis. Additionally, molecular modeling investigated the conformational characteristics of all trimers and tetramers, 1-5. Our findings suggest that the specific interflavan linkages significantly impact the flexibility and low-energy conformations of the connected monomeric units, which conversely can affect the bioactive conformations relevant for dentin biomodification.
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Affiliation(s)
| | - Connor M McDermott
- Department of Chemistry, Grandview University, Des Moines, Iowa 50316, United States
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Jing SX, Ferreira D, Pandey P, Klein LL, Chittiboyina AG, McAlpine JB, Lankin DC, Alania Y, Reis-Havlat M, Bedran-Russo AK, Chen SN, Pauli GF. Unprecedented Benzoquinone Motifs Reveal Post-Oligomerizational Modification of Proanthocyanidins. J Org Chem 2023; 88:13490-13503. [PMID: 37748101 PMCID: PMC10921432 DOI: 10.1021/acs.joc.3c00950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Proanthocyanidins (PACs) are complex flavan-3-ol polymers with stunning chemical complexity due to oxygenation patterns, oxidative phenolic ring linkages, and intricate stereochemistry of their heterocycles and inter-flavan linkages. Being promising candidates for dental restorative biomaterials, trace analysis of dentin bioactive cinnamon PACs now yielded novel trimeric (1 and 2) and tetrameric (3) PACs with unprecedented o- and p-benzoquinone motifs (benzoquinonoid PACs). Challenges in structural characterization, especially their absolute configuration, prompted the development of a new synthetic-analytical approach involving comprehensive spectroscopy, including NMR with quantum mechanics-driven 1H iterative functionalized spin analysis (HifSA) plus experimental and computational electronic circular dichroism (ECD). Vital stereochemical information was garnered from synthesizing 4-(2,5-benzoquinone)flavan-3-ols and a truncated analogue of trimer 2 as ECD models. Discovery of the first natural benzoquinonoid PACs provides new evidence to the experimentally elusive PAC biosynthesis as their formation requires two oxidative post-oligomerizational modifications (POMs) that are distinct and occur downstream from both quinone-methide-driven oligomerization and A-type linkage formation. While Nature is known to achieve structural diversity of many major compound classes by POMs, this is the first indication of PACs also following this common theme.
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Affiliation(s)
- Shu-Xi Jing
- Pharmacognosy Institute, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
- Department of Pharmaceutical Science, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Daneel Ferreira
- Department of Biomolecular Sciences, The University of Mississippi, University, Mississippi 38677, USA
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, Mississippi 38677, USA
| | - Pankaj Pandey
- Department of Biomolecular Sciences, The University of Mississippi, University, Mississippi 38677, USA
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, Mississippi 38677, USA
| | - Larry L. Klein
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
- Department of Pharmaceutical Science, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Amar Gopal Chittiboyina
- Department of Biomolecular Sciences, The University of Mississippi, University, Mississippi 38677, USA
- National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, Mississippi 38677, USA
| | - James B. McAlpine
- Pharmacognosy Institute, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
- Department of Pharmaceutical Science, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - David C. Lankin
- Pharmacognosy Institute, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
- Department of Pharmaceutical Science, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Yvette Alania
- Department of General Dental Sciences, School of Dentistry, Marquette University, Milwaukee, Wisconsin 53233, USA
| | - Mariana Reis-Havlat
- Department of General Dental Sciences, School of Dentistry, Marquette University, Milwaukee, Wisconsin 53233, USA
| | - Ana K. Bedran-Russo
- Department of General Dental Sciences, School of Dentistry, Marquette University, Milwaukee, Wisconsin 53233, USA
| | - Shao-Nong Chen
- Pharmacognosy Institute, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
- Department of Pharmaceutical Science, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Guido F. Pauli
- Pharmacognosy Institute, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
- Department of Pharmaceutical Science, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
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Guo J, Yang M, Hu M. The roles of theaflavins in reducing dentin erosion. Sci Rep 2023; 13:9413. [PMID: 37296182 PMCID: PMC10256681 DOI: 10.1038/s41598-023-35382-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 05/17/2023] [Indexed: 06/12/2023] Open
Abstract
This study aimed to evaluate the effect of theaflavins [TFs] on the process of dentin erosion and investigation the potential mechanism. For erosion kinetics of the dentin, 7 experimental groups (n = 5) treated with 10% ethanol [EtOH] (negative control) are erosion for 1, 2, 3, 4, 5, 6, and 7 d erosion cycles (4 cycles/d). For the effect of TFs on dentin erosion, 6 experimental groups (n = 5) were treated with 1% epigallocatechin gallate [EGCG], 1% chlorhexidine [CHX], 1%, 2%, 4%, and 8% TFs for the 30 s and then subjected to erosion cycles (4 cycles/d for 7 d). The erosive dentin wear (μm) and surface morphology were evaluated and compared by laser scanning confocal microscope and scanning electron microscopy. The matrix metalloproteinase inhibition effects of TFs were investigated using in situ zymography and molecular docking. TFs-treated collagen was investigated by ultimate microtensile strength, Fourier-transform infrared spectroscopy, and molecular docking. Data were analyzed by ANOVA, Tukey's test (P < 0.05). The TFs-treated groups (7.56 ± 0.39, 5.29 ± 0.61, 3.28 ± 0.33, and 2.62 ± 0.99 μm for 1%, 2%, 4%, and 8% TFs) had significantly lower erosive dentin wear than the negative control group (11.23 ± 0.82 μm), and the effect was concentration-dependent at low concentrations (P < 0.05). TFs inhibit matrix metalloproteinase [MMP]. Moreover, TFs crosslink dentin collagen and cause hydrophilic changes in dentin collagen. TFs preserve organic matrix within the demineralized dentin by inhibiting MMP activity and simultaneously improving collagen's resistance to enzymes, both of which contribute to preventing or slowing down the progression of dentin erosion.
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Affiliation(s)
- Jing Guo
- Department of Dental General and Emergency, The Affiliated Stomatological Hospital of Nanchang University, No. 688 Honggu North Road, Honggutan District, Nanchang, 330038, People's Republic of China.
- The Key Laboratory of Oral Biomedicine, Nanchang, Jiangxi Province, People's Republic of China.
- Jiangxi Province Clinical Research Center for Oral Diseases, Nanchang, People's Republic of China.
| | - Mingqi Yang
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, People's Republic of China
| | - Mengna Hu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, People's Republic of China
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