Application of ¹H‐NMR‐based metabolomics to the analysis of cranberry (Vaccinium macrocarpon) supplements

Abstract

Introduction Commercial cranberry supplements provide a low‐sugar alternative to juices and sweetened fruit consumed for health benefits, but their phytochemical composition and associated biological activity varies depending on the source material and post‐harvest processing. Proton nuclear magnetic resonance (1H‐NMR) is a rapid and environmentally friendly method of generating metabolic profiles of plant materials that may be used to authenticate cranberry products. Objective The 1H NMR‐based chemometrics were used to characterise variations in metabolic profiles of cranberry supplements in comparison to a whole cranberry powder reference standard. Materials and Methods The secondary metabolite profiles of nine commercial cranberry supplements were compared to a whole cranberry powder reference standard, using 1H‐NMR with Bruker AssureNMR software and principal component analysis (PCA). Content of selected triterpenoids and organic acids was determined by quantitative NMR. Total proanthocyanidins and anthocyanins were determined by established methods. Results PCA of 1H‐NMR spectra showed overlap between the cranberry standard and three supplements, but most products varied substantially in metabolic profile. Metabolites contributing to the observed variance include citric acid and cranberry peel constituents ursolic acid, oleanolic acid and hyperoside. Ursolic, oleanolic, citric, quinic and malic acids were readily determined by quantitative 1H‐NMR in the whole cranberry standard, but were below detection limits in many supplements. Proanthocyanidin and flavonoid content in several products was minimal or below detection limits. Conclusion The 1H‐NMR chemometrics found significant variation in composition of characteristic cranberry metabolites among commercial preparations, reinforcing the need for reliable industry standards

Proanthocyanidin-enriched cranberry extract induces resilient bacterial community dynamics in a gnotobiotic mouse model

“…Briefly, total proanthocyanidin (PAC) content was determined using a modification [46] of the industry standard microplate BL-DMAC assay [47]. An isolated whole fruit cranberry PAC fraction prepared as described previously [28] was used as the standard for the DMAC method, and absorbance measurements were obtained using a microplate reader (Molecular Devices SpectraMax M5, SoftMax Pro V5) as described in [36].…”

“…Identification and quantitation of anthocyanins and flavonol glycosides was performed via reversed-phase HPLC-DAD using a Waters HPLC binary system with 515 pumps coupled with a Waters 996 photodiode array detector and Waters Millenium32 software, as described previously. [36]. Briefly, analyses employed a Waters Atlantis C18 column (100 Å, 3 μm, 3.9 mm x 150 mm) and gradient elution at a flow rate of 0.9 mL/min with mobile phases consisting of 99.5:0.5 (v/v) water:phosphoric acid (A) and 50:48.5:1:0.5 (v/v/v/v) water:acetonitrile:acetic acid:phosphoric acid (B) according to a published gradient scheme as in [48] Flavonol glycosides were detected at a wavelength of 355 nm and quantified based on a quercetin-3-O-glycoside standard; anthocyanins were detected at 520 nm and quantified based on cyanidin-3-O-galactoside and peonidin-3-O-galactoside standards as previously described [6].…”

“…1 H NMR analysis. A qualitative profile of CJE was generated, and quantitative NMR to determine several non-polyphenol metabolites was conducted using a Bruker AVANCE III 400 MHz NMR spectrometer equipped with a 5mm BBFO z-gradient probe, as described previously [36]. Briefly, samples were prepared (n=5) at 75 mg/mL in DMSO-d6 with 4,4-dimethyl-4-silapentane-1sulfonic acid as a reference standard.…”

Vaccinium macrocarpon (Cranberry)-Based Dietary Supplements: Variation in Mass Uniformity, Proanthocyanidin Dosage and Anthocyanin Profile Demonstrates Quality Control Standard Needed

“…However, all these techniques employ chromatographic systems, but are not always coupled with mass spectrometers. For example, the presence of V. macrocarpon fruit in processed products may be checked through the analysis of the general phenolic compositions [46], or focusing on specific bioactive compounds, such as proanthocyanidins [47] or anthocyanins [48,49]. In this context, chemical fingerprinting based on proanthocyanidins or other polyphenols may be less accurate when DS are deliberately adulterated with plants with a similar phytochemical composition.…”

Oligosaccharides and Complex Carbohydrates: A New Paradigm for Cranberry Bioactivity

“…Whole berries may also be processed into specialty foods or extracts by various methods, and products include sweetened dried cranberries [34,42], canned cranberry sauce [43][44][45], and various foods to which cranberry materials have been added. that many such products may contain adulterants, may have low total cranberry content, or may lack most of the diverse cranberry phytochemicals that are believed to contribute to biological activity [48][49][50][51][52][53]. Flow diagram showing generalized processing steps and relative relationships for different cranberry materials.…”