Quantification of cranberry proanthocyanidins by normal-phase high-performance liquid chromatography using relative response factors.

INTRODUCTION: American cranberries (Vaccinium macrocarpon) contain primarily A-type proanthocyanidins (PACs), which have been shown to prevent urinary tract infection. Currently, the accurate quantification of cranberry PACs is still lacking. OBJECTIVE: A normal-phase high-performance liquid chromatography (NP-HPLC) method using relative response factors was developed and validated to quantify cranberry PAC oligomers and polymers. MATERIALS AND METHODS: PAC oligomers with degree of polymerisation (DP) 3-9 and total polymers were isolated from the cranberry juice concentrate. Characterisation of the isolated PAC oligomers was performed by ultra-performance liquid chromatography-high resolution mass spectrometry. The relative response factors of oligomers from DP 2-9 and total polymers were determined against procyanidin A2. Method validation was conducted to assess limit of detection, limit of quantification, the linearity and working range, precision and accuracy. In addition, quantifications of PACs by NP-HPLC using relative response factors and two other commonly used methods were conducted in three cranberry food products. RESULTS: Cranberries PACs oligomers contained both A-type and B-type linkage, with epicatechin and epigallocatechin as basic units. Method validation results suggested this method is reliable and reproducible. Quantifications of PACs by NP-HPLC using relative response factors yielded higher values than that by the other two methods. CONCLUSION: A NP-HPLC method using the relative response factors was developed and validated. This method provides a more accurate approach in determining cranberry PACs. It can be used to quantify individual oligomers from DP 2-9, total polymers and total PACs in cranberries and cranberry products.

Phytochemical and physical properties of blueberries, tart cherries, strawberries, and cranberries as affected by different drying methods.

The effects of hot-air drying (AD), freeze drying (FD) and Refractance Window drying (RWD) on the retention of anthocyanins, phenolics, flavonoids, vitamin C and B, and antioxidant capacity (ORAC) in blueberries, tart cherries, strawberries, and cranberries, as well as organic acids and proanthocyanins in cranberries and chlorogenic acid and catchins in blueberries were evaluated. Changes in color, glass transition, specific heat, and surface morphology of the dried fruits were also evaluated. The quality retention in the dried fruits was found to be product and drying method specific. The FD products exhibited a better retention of vitamin C, ORAC, anthocyanins, and phenolics than the AD and RWD fruits. The RWD produced samples with a less effective ORAC, anthocyanins, and phenolics retention, but a higher total vitamin B retention compared to the FD products. The AD-dried fruits displayed significantly lesser quality retention in most of the quality indexes measured in the study.

Single-Laboratory Validation for Determination of Total Soluble Proanthocyanidins in Cranberry Using 4-Dimethylaminocinnamaldehyde.

American cranberry (Vaccinium macrocarpon) is native to Eastern North America. Recent studies have suggested that the A-type proanthocyanidins (PACs) in cranberries are effective in preventing urinary tract infection. To meet the growing interest in the cranberry market, an accurate, reliable, and simple method to determine PAC concentration is needed. In this study, a modified method using 4-dimethylaminocinnamaldehyde to quantify total PACs in cranberry products was validated. Cranberry juice extract powder, cranberry capsules containing juice extract, and cranberry juice concentrate were used as the samples in this study. With the modified method, the calibration curves for proanthocyanidin A2 had correlation coefficients (r2) of >0.99. The recoveries of two different concentrations after spiking were 97.1 and 99.1%, and the RSDs for repeatability and reproducibility were <2.7 and <1.6%, respectively.

Rapid quantitation of avenanthramides in oat-containing products by high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-TQMS).

Avenanthramides (AVNs) are a family of nitrogen-containing phenolic compounds produced in oat; AVN 2c, 2p, and 2f are the three major members. An LC-MS/MS method was developed, with the limit of detection (LOD) and the limit of quantitation (LOQ) being, respectively, 0.29ng/mL and 1.96ng/mL for AVN 2c, 0.24ng/mL and 0.60ng/mL for AVE 2p, and 0.42ng/mL and 2.2ng/mL for AVN 2f. The method was validated in oat-containing hot cereal and snack bar samples. The recovery of AVN 2c, 2p, and 2f from these two oat products was 95-113%, and the relative standard deviations ranged from 5% to 9%. This method was used to evaluate oat products and raw oat samples. The effects of location and variety on AVN composition were investigated. The method presented here provides a novel and rapid tool to quantitate the abundance of AVN 2c, 2p, and 2f in oat-containing products.

Daily consumption of a mangosteen-based drink improves in vivo antioxidant and anti-inflammatory biomarkers in healthy adults: a randomized, double-blind, placebo-controlled clinical trial.

Mangosteen (Garcinia mangostana) is a tropical fruit cultivated mainly in Southeast Asia. Recent studies have shown mangosteen has many health benefits. In this study, we aimed to determine the effects of a mangosteen-based beverage on antioxidant and anti-inflammatory and immunity biomarkers in plasma of healthy adults. A randomized, double-blind, placebo-controlled clinical trial was conducted using 60 participants, 30 men, and 30 women, ages 18-60. Participants were randomly divided into two groups, placebo and mangosteen groups, with the same number of male and female participants in each group. The trial duration was 30 days. ORAC as an antioxidant biomarker was measured in both groups. It was found that after the 30-day trial, the group given the mangosteen-based drink formula showed 15% more antioxidant capacity in the bloodstream than did the placebo group. As for the inflammatory biomarkers, in the mangosteen group, between the preintervention and postintervention, the C-reactive protein level significantly decreased by 46%, while no significant decreases for the same biomarker was observed in the placebo group. Immunity biomarkers IgA, IgG, IgM, C3 and C4 were not affected in either group. In addition, the effects on hepatic function (Aspartate Aminotransferase and Alanine Aminotransferase) and kidney function (creatinine) were investigated. Our results indicated that after the 30-day consumption of the beverage, there were no side effects on human hepatic and kidney functions. The outcome of this study showed that the mangosteen-based formula significantly increases antioxidant capacity and possesses anti-inflammatory benefits with no side effects on immune, hepatic, and renal functions for long-term consumption.

Functional beverage of Garcinia mangostana (mangosteen) enhances plasma antioxidant capacity in healthy adults.

This study was to investigate the absorption and antioxidant effect of a mangosteen-based functional beverage in humans. The beverage contained mangosteen, aloe vera, green tea, and multivitamins. A randomized, double-blind, placebo-controlled clinical trial was conducted with generally healthy male and female subjects between 18 and 60 years of age. Ten men and 10 women participated in this study. Participants were randomly divided into two groups, treatment and placebo group. Participants received either a daily single dose (245 mL) of the beverage or a placebo. Blood samples were collected from each participant at time points 0, 1, 2, 4, and 6 h. The plasma samples were analyzed by LC/MS for α-mangostin and vitamins B2 and B5. Results indicated that the three analytes were bioavailable, with observed C max at around 1 h. The antioxidant capacity measured with the oxygen radical absorbance capacity (ORAC) assay was increased with a maximum effect of 60% after 1 h, and the elevated antioxidant level lasted at least 6 h. This study demonstrated the bioavailability of α-mangostin and B vitamins from a xanthone-rich beverage and the mechanisms of the increase in plasma antioxidant may be direct effects from antioxidants, enhancement of endogenous antioxidant activity through activation of Nrf2 pathway, and synergism of the antioxidants.