Preparation, Modification, Quantitation, and Dentin Biomodification Activity of Selectively Enriched Proanthocyanidins.

To date, quantitative analysis of proanthocyanidin (PAC) containing materials including plant extracts and fractions depends on colorimetric assays or phloroglucinolysis/thiolysis combined with UV-HPLC analysis. Such assays are of limited accuracy, particularly lack specificity, require extensive sample preparation and degradation, and need appropriate physical reference standards. To address this analytical challenge and toward our broader goal of developing new plant-sourced biomaterials that chemically and mechanically modulate the properties of dental tissue for clinical interventions, we have characterized 12 different PAC DESIGNER (Depletion and Enrichment of Select Ingredients Generating Normalized Extract Resources) materials.

Prodelphinidins enhance dentin matrix properties and promote adhesion to methacrylate resin.

Objective: Investigate the bioactivity and stability of Rhodiola rosea (RR) fractions as a natural source of prodelphinidin gallate (PDg) on dentin collagen via analysis of the viscoelastic and resin-dentin adhesive properties of the dentin matrix.

Methods: The biomimicry and stability of RR subfractions (F1, F2, F3 and F4) with collagen were determined by dynamic mechanical analysis (DMA). DMA used a strain sweep method to assess the dentin matrix viscoelastic properties [storage (E'), loss (E"), and complex (E*) moduli and tan δ] after treatment, 7-, 30- and 90-days of storage in simulated body fluids (SBF).

Modulatory role of terminal monomeric flavan-3-ol units in the viscoelasticity of dentin.

Flavan-3-ol monomers are the building blocks of proanthocyanidins (PACs), natural compounds from plants shown to mediate specific biologic activities on dentin. While the stereochemistry of the terminal flavan-3-ols, catechin (C) versus epicatechin (EC), impacts the biomechanical properties of the dentin matrix treated with oligomeric PACs, structure-activity relationships driving this bioactivity remain elusive. To gain insights into the modulatory role of the terminal monomers, two highly congruent trimeric PACs from Pinus massoniana only differing in the stereochemistry of the terminal unit (Trimer-C vs.

Unprecedented Benzoquinone Motifs Reveal Post-Oligomerizational Modification of Proanthocyanidins.

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 ( and ) and tetrameric () PACs with unprecedented - and 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 H iterative functionalized spin analysis (HifSA) plus experimental and computational electronic circular dichroism (ECD).

The Ethics of Publishing Biomedical and Natural Products Research.

Given that the essence of Science is a search for the truth, one might expect that those identifying as scientists would be conscientious and observant of the demands this places on them. However, that expectation is not fulfilled universally as, not too surprisingly, egregious examples of unethical behavior appear and are driven by money, personal ambition, performance pressure, and other incentives. The reproducibility-, fact-, and truth-oriented of Science has come to face a variety of challenges.

DESIGNER fraction concept unmasks minor bioactive constituents in red clover (Trifolium pratense L.).

In botanical extracts, highly abundant constituents can mask or dilute the effects of other, and often, more relevant biologically active compounds. To facilitate the rational chemical and biological assessment of these natural products with wide usage in human health, we introduced the DESIGNER approach of Depleting and Enriching Selective Ingredients to Generate Normalized Extract Resources. The present study applied this concept to clinical Red Clover Extract (RCE) and combined phytochemical and biological methodology to help rationalize the utility of RCE supplements for symptom management in postmenopausal women.

Geraniol-Derived Monoterpenoid Glucosides from : Resolving Structures by QM-HifSA Methodology.

Monoterpenoids are integral to the chemical composition of the widely used adaptogenic dietary supplement . The present study expands the chemical space and stereochemical information about these taxon-specific constituents from the isolation and characterization of five geraniol-derived glucosides, -. While and exhibited almost identical NMR spectra and shared the same 2D structure ascribed to the 4-hydroxygeraniolglucoside previously described as rosiridin, the NMR-based Mosher ester method revealed the enantiomeric nature of their aglycone moieties.

B-Type Oligomers from Expand the Procyanidin Chemical Space and Exhibit Dental Bioactivity.

Investigation of a pine bark extract for bioactive proanthocyanidin oligomers resulted in the isolation of structurally related dimeric B-type procyanidin derivatives, -. This includes scalemic mixtures of gambiriin A1 () and A2 () and their newly described optical antipodes, -gambiriin A1 () and -gambiriin A2 (), respectively, as well as a racemic mixture of the newly described (-)gambiriin A5 (/). Furthermore, the study now fully characterizes the previously reported optically pure dimers gambiriin B1 () and gambirflavan D1 (), and characterized the novel B-type procyanidin trimer, (gambirifuran C1).

New Rufomycins from MJM3502 Expand Anti- Structure-Activity Relationships.

Four new rufomycins, compounds -, named rufomycins 56, 57, 58, and 61, respectively, exhibiting new skeletal features, were obtained from strain MJM3502 and were fully characterized. Compounds and possess a 4-imidazolidinone ring not previously encountered in this family of cyclopeptides, thereby resulting in a [5,17] bicyclic framework. The in vitro anti- potency of compounds and is remarkable, with minimum inhibitory concentration values of 8.

B-type Proanthocyanidins with Dentin Biomodification Activity from Cocoa ().

To enable translational studies, a scalable preparative isolation scheme was developed for underivatized cocoa () proanthocyanidins (PACs), affording six all-B-type oligomeric PACs, including a new tetramer . Their structures, including absolute configuration, were unambiguously established by comprehensive spectroscopic and chemical methods. Evaluation of the PACs' dentin biomodification properties employed dynamic mechanical and infrared spectroscopic analyses in dentin bioassay models.

Proanthocyanidin Tetramers and Pentamers from Bark and Their Dentin Biomodification Bioactivities.

To enable the further exploration of structure-activity relationships (SARs) of proanthocyanidins (PACs) with dentin biomodification abilities, was selected for scaled-up purification of mixed A-/B-type, medium-size PAC oligomers. Sequential purification by centrifugal partition chromatography (CPC), Sephadex LH-20, and semiprep HPLC chromatography yielded four underivatized tetrameric (-) and two pentameric (-) PACs. Their unambiguous structural characterization involved extensive spectral and chemical degradation approaches to show that epicatechin units are connected by plant-specific combinations of doubly linked A- and singly linked B-type interflavanyl bonds.

Selective Preparation and High Dynamic-Range Analysis of Cannabinoids in "CBD Oil" and Other Preparations.

Much confusion exists about the chemical composition of widely sold products that utilize the cannabidiol (CBD) acronym and related terms such as "CBD oil", "CBD plus hemp oil", "full spectrum CBD", "broad spectrum CBD", and "cannabinoids". Their rational chemical and subsequent biological assessment requires both knowledge of the chemical complexity and the characterization of significant individual constituents. Applicable to hemp preparations in general, this study demonstrates how the combination of liquid-liquid-based separation techniques, NMR analysis, and quantum mechanical-based NMR interpretation facilitates the process of natural product composition analysis by allowing specific structural characterization and absolute quantitation of cannabinoids present in such products with a large dynamic range.

Do Certain Flavonoid IMPS Have a Vital Function?

Flavonoids are a vast group of metabolites that are essential for vascular plant physiology and, thus, occur ubiquitously in plant-based/-derived foods. The solitary designation of thousands of known flavonoids hides the fact that their metabolomes are structurally highly diverse, consist of disparate subgroups, yet undergo a certain degree of metabolic interconversion. Unsurprisingly, flavonoids have been an important theme in nutrition research.

Rufomycins or Ilamycins: Naming Clarifications and Definitive Structural Assignments.

Rufomycin and ilamycin are synonymous for the same class of cyclopeptides, currently encompassing 33 structurally characterized isolates and 9 semisynthetic derivatives. Elucidation of new structures prioritized the consolidation of the names and established the structures of four diastereoisomeric rufomycins with a 2-piperidinone, named rufomycins 4-7, including full H/C NMR assignments. The characteristic HSQC cross-peak for the CH-5, the hemiaminal carbon in amino acid #5, allows assignment of the stereocenters C-4 and C-5 within this ring.

Tandem of Countercurrent Separation and qHNMR Enables Gravimetric Analyses: Absolute Quantitation of the Metabolome.

Off-line combination of countercurrent separation (CCS) and quantitative H NMR (qHNMR) methodologies enabled the systematic dissection and gravimetric quantification of a chemically complex crude extract (RCE). The loss-free nature and high selectivity of CCS achieved the quantitative discrimination of fatty acids (FAs), sugars, and proanthocyanidins (PACs) from ten other metabolite classes: phenylpropanoids, phenylethanoids, acyclic monoterpenoid glycosides, pinene derived glycosides, benzyl alcohol glycosides, cyanogenic glycosides, flavonoids, gallic acids, methylparabens, and cuminol glycosides. The ability of CCS to remove ("knockout") PACs completely resolved challenges with baselines that plague NMR and UHPLC analyses and produce inaccurate integral and AUC quantitation, respectively.

Investigation of red clover (Trifolium pratense) isoflavonoid residual complexity by off-line CCS-qHNMR.

The importance of Trifolium pratense L. as a dietary supplement and its use in traditional medicine prompted the preparation of a thorough metabolite profile. This included the identification and quantitation of principal constituents as well as low abundant metabolites that constitute the residual complexity (RC) of T.

Paradoxical effects of galloyl motifs in the interactions of proanthocyanidins with collagen-rich dentin.

Plant-derived proanthocyanidins (PACs) mediate physicochemical modifications to the dentin extracellular matrix (ECM). The structure-activity relationships of PACs remain largely unknown, mostly due to the varied complex composition of crude extracts, as well as the challenges of purification and mechanistic assessment. To assess the role of galloylated PACs as significant contributors to high yet unstable biomodification activity to the dentin ECM, we removed the galloyl moieties (de-galloylation) via enzymatic hydrolysis from three galloyl-rich PAC-containing extracts (Camellia sinensis, Vitis vinifera, and Hamamelis virginiana).

Silica Gel-mediated Oxidation of Prenyl Motifs Generates Natural Product-Like Artifacts.

Prenyl moieties are commonly encountered in the natural products of terpenoid and mixed biosynthetic origin. The reactivity of unsaturated prenyl motifs is less recognized and shown here to affect the acyclic monoterpene glycoside, kenposide A (8: ), which oxidizes readily on silica gel when exposed to air. The major degradation product mediated under these conditions was a new aldehyde, 9: .

The Untargeted Capability of NMR Helps Recognizing Nefarious Adulteration in Natural Products.

(turmeric) has an extensive history of ethnomedical use for common ailments, and "curcumin"-containing dietary supplements (CDS) are a highly visible portion of today's self-medication market. Owing to raw material cost pressure, CDS products are affected by economically motivated, nefarious adulteration with synthetic curcumin ("syncumin"), possibly leading to unexpected toxicological issues due to "residual" impurities. Using a combination of targeted and untargeted (phyto)chemical analysis, this study investigated the botanical integrity of two commercial "turmeric" CDS with vitamin and other additives that were associated with reported clinical cases of hepatotoxicity.

Targeting Trimeric and Tetrameric Proanthocyanidins of Bark as Bioactives for Dental Therapies.

The present study elucidated the structures of three A-type tri- and tetrameric proanthocyanidins (PACs) isolated from bark to the level of absolute configuration and determined their dental bioactivity using two therapeutically relevant bioassays. After selecting a PAC oligomer fraction via a biologically diverse bioassay-guided process, in tandem with centrifugal partition chromatography, phytochemical studies led to the isolation of PAC oligomers that represent the main bioactive principles of : two A-type tetrameric PACs, epicatechin-(2β→→7,4β→8)-epicatechin-(4β→6)-epicatechin-(2β→→7,4β→8)-catechin () and parameritannin A1 (), together with a trimer, cinnamtannin B1 (). Structure determination of the underivatized proanthocyanidins utilized a combination of HRESIMS, ECD, 1D/2D NMR, and H iterative full spin analysis data and led to NMR-based evidence for the deduction of absolute configuration in constituent catechin and epicatechin monomeric units.

Quantum mechanical NMR full spin analysis in pharmaceutical identity testing and quality control.

Issues related to pharmaceutical quality are arising at an alarming rate. Pharmaceutical quality concerns both the Active Pharmaceutical Ingredients (APIs) and the Finished Drug Product/ Formulation. Recently, there has been a significant increase in the number of reports of harmful impurities in marketed drug formulations.

Rare A-Type, Spiro-Type, and Highly Oligomeric Proanthocyanidins from .

An investigation of the dental bioactive proanthocyanidin (PAC) oligomer fractions led to three structurally distinct new PACs (-) from pine bark. Pinutwindoublin () is the first reported trimer with double A-type interflavanyl linkages (2α→O→5,4α→6 and 2α→O→7,4α→8). Pinuspirotetrin () represents the first reported PAC tetramer with a heterodimeric framework consisting of one spiro-type and one A-type dimer.