Determination of anthocyanins, organic acids, and phenolic acids in hibiscus market products using LC/UV/MS.

Hibiscus sabdariffa has gained increasing attention from consumers as a natural, healthy food ingredient, leading to a myriad of available products, yet there is a lack of understanding of the quality and chemical diversity among commercially available hibiscus products. Here, we conducted a survey on the chemistry of 29 hibiscus products (calyces, beverages, and extracts). UHPLC-DAD and UHPLC-QQQ/MS methods with high sensitivity and selectivity were developed to evaluate the chemical profiles pertaining to the sensory attributes (color and taste). Two major anthocyanins (delphinidin-3-sambubioside and cyanindin-3-sambubioside), eight organic acids, and 23 phenolic acids were identified and quantified in hibiscus market products. The results showed that hibiscus samples contained < 0.001-2.372% of total anthocyanins, 0.073-78.002% of total organic acids, and 0.001-1.041% of total phenolic acids, and demonstrated significant variations in market products. This is the first time that an in-depth organic acid profiling was conducted on hibiscus products using UHPLC-QQQ/MS. This method can also be extended to chemical profiling, sensory analysis, quality control, authentication, and standardization of other natural products.

Kinkéliba (Combretum micranthum) Leaf Extract Alleviates Skin Inflammation: In Vitro and In Vivo Study.

Kinkéliba (Combretum micranthum, Seh-Haw in Wolof) is a popular bush tea in West African countries. Although the kinkéliba plant's leaves have been widely consumed for its nutritional and medicinal properties, its benefits on skin health potential have been practically untouched. In human epidermal primary keratinocytes, vitexin and isovitexin-rich kinkéliba extract treatment significantly (p < 0.001) enhanced up to 39.6% of the cell survival rate decreased by UV radiation irritation. The treatment of kinkéliba leaf extracts also reduced the production of UV-induced pro-inflammatory cytokines IL-6 and IL-8 by 57.6% and 42.5%, respectively (p < 0.001), which cause skin redness and skin barrier dysfunction, as well as wrinkles and collagen degradation. The anti-inflammation efficacy of kinkéliba leaf extracts might involve significant inhibition on the levels of cellular reactive oxygen species (ROS) (-70.8%, p < 0.001) and nitrotyrosine (-56.9%, p < 0.05). Further topical applications of kinkéliba leaf extract gel were found to reduce sodium lauryl sulfate (SLS)-induced skin inflammation: at D7, the skin trans-epidermal water loss (TEWL) and skin redness (a* value) were both reduced by 59.81% (p < 0.001) and 22.4% (p < 0.001), compared with D0. In vitro and in vivo data support a new topical application of the kinkéliba leaf as an effective active ingredient for the treatment of skin inflammation, as well as subsequent barrier dysfunction and inflammaging.

Investigation of Volatile Iridoid Terpenes in Nepeta cataria L. (Catnip) Genotypes.

Catnip (Nepeta cataria L.) is of scientific interest largely due to the production of nepetalactones, volatile iridoid terpenes with strong arthropod repellent activity. However, the plant can also produce other bioactive volatile iridoids, such as nepetalic acid (NA), nepetalactam (NT) and dihydronepetalactone (DHNL) that have not been studied extensively. Germplasm studies on plants that can produce such compounds are scarce. The present study evaluated the chemical diversity of catnip genotypes with a focus on NA, NT and DHNL. A total of 34 genotypes were harvested at different times over two years. The ethanolic extract of the plants was screened for iridoids by ultra-high-performance liquid chromatography/triple quadrupole mass spectrometry. CR9 × CR3 genotype had the highest value for biomass yield, while cultivar CR9 had the highest value for accumulated NA. Genotype UK.2 had the highest value for accumulated NT yield and CR5 had the highest value for accumulated DHNL. Overall, patented cultivars and elite selections performed better than other less studied genotypes. Harvest time influenced the accumulation of secondary metabolites differentially for the genotypes. This is the first germplasm study with a focus on these iridoid compounds, yet more studies are necessary as genotype characterization is essential for breeding and standardization of products for industry.

Antiviral activity of aframomum melegueta against severe acute respiratory syndrome coronaviruses type 1 and 2.

Plant-based compounds with antiviral properties against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been identified in Aframomum melegueta through computational models. The seed extract have been traditionally used to treat different illnesses. In this study, ethanolic extracts were prepared for six commercial samples of A. melegueta seeds. Antiviral activity was tested using the XTT cytotoxicity assay and cell-based SARS-CoV-1 and 2 pseudoviral models. The presence of gingerols and other non-volatile components in the seed extracts was determined using an Agilent 1290 UPLC/DAD in tandem with an Agilent 6546 QTOF-MS. Our results showed selective antiviral activity with TI values as high as 13.1. Fifteen gingerols were identified by chromatographic analysis, with 6-gingerol being the dominant component in each seed extract. A combination of 6-gingerol with techtochrysin, previously identified in computational models as a potential active ingredient against SARS-CoV-2, demonstrated additive antiviral activity with CI values between 0.8715 and 0.9426. We confirmed the antiviral activity of A. melegueta predicted through computational models and identified a different compound, 6-gingerol, as a potential active ingredient.

Changes in polyphenol serum levels and cognitive performance after dietary supplementation with Concord grape juice in veterans with Gulf War Illness.

AIMS: We investigated whether the consumption of Concord grape juice (CGJ) was associated with increased bioavailability of serum metabolites and their potential impact on cognitive performance in Veterans with Gulf War Illness (GWI). MAIN METHODS: Twenty-six veterans were selected from a cohort of 36 enrolled in a 24-week randomized, double-blind, Phase I/IIA clinical trial exploring whether the consumption of Concord grape juice (CGJ) was tolerable and safe in Veterans with GWI and improved cognitive function and fatigue. These 26 veterans were selected based on their completion of the entire 24-week protocol and documented adherence to the study beverage ≥80%. Differences in serum metabolite levels between CGJ and placebo at midpoint and endpoint were evaluated using two-way repeated measures ANOVA with post hoc Sidak's multiple comparison test. Bivariate correlations to assess for possible relationships between change in serum metabolite levels and change in cognitive function as measured by the Halstead Category Test-Russell Revised Version (RCAT) were also conducted. KEY FINDINGS: Seventy-six metabolites were identified and quantified in this study, with three (cyanidin-glucuronide, me-cyanidin-glucuronide, and me-malvidin-glucuronide) found to be significantly higher (p < 0.05) in the CGJ group compared to placebo at 24 weeks. Significant associations between changes in cognitive function and changes in serum levels of epicatechin-sulphate (r = 0.48, p = 0.01) and petunidin-glucuronide (r = 0.53, p < 0.01) from baseline to 24 weeks were also observed. SIGNIFICANCE: Our data suggest that dietary supplementation with CGJ is associated with increased bioavailability of specific phenolic metabolites, some of which may be correlated with cognitive performance.

Neuroprotective mechanisms of red clover and soy isoflavones in Parkinson's disease models.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by nigrostriatal degeneration and the spreading of aggregated forms of the presynaptic protein α-synuclein (aSyn) throughout the brain. PD patients are currently only treated with symptomatic therapies, and strategies to slow or stop the progressive neurodegeneration underlying the disease's motor and cognitive symptoms are greatly needed. The time between the first neurobiochemical alterations and the initial presentation of symptoms is thought to span several years, and early neuroprotective dietary interventions could delay the disease onset or slow PD progression. In this study, we characterized the neuroprotective effects of isoflavones, a class of dietary polyphenols found in soy products and in the medicinal plant red clover (Trifolium pratense). We found that isoflavone-rich extracts and individual isoflavones rescued the loss of dopaminergic neurons and the shortening of neurites in primary mesencephalic cultures exposed to two PD-related insults, the environmental toxin rotenone and an adenovirus encoding the A53T aSyn mutant. The extracts and individual isoflavones also activated the Nrf2-mediated antioxidant response in astrocytes via a mechanism involving inhibition of the ubiquitin-proteasome system, and they alleviated deficits in mitochondrial respiration. Furthermore, an isoflavone-enriched soy extract reduced motor dysfunction exhibited by rats lesioned with the PD-related neurotoxin 6-OHDA. These findings suggest that plant-derived isoflavones could serve as dietary supplements to delay PD onset in at-risk individuals and mitigate neurodegeneration in the brains of patients.

Rapid screening of glycoalkaloids in Solanum scabrum and S. nigrum berries using ultra-high-performance liquid chromatography with pathway-specified in-source fragmentation tandem mass spectrometry.

RATIONALE: The safe consumption of Solanum scabrum and S. nigrum berries (SNBs) depends on a reliable and rapid chemical screen for the testing of the fruit and/or final food and industrial products for the presence and level of toxic glycoalkaloids. Such a rapid and sensitive screen could also be used by those involved in food safety and forensics, industry, research labs and those in agriculture production, breeding and food processing. Significant variation in the content and composition of glycoalkaloids across SNBs has been reported. To facilitate high-throughput targeted analysis, this work overcame the slow scan speed of a traditional triple quadruple mass spectrometry (QqQ) method by development of a pseudo-MS3 method. METHODS: In-source fragmentation functioned as a pseudo-MS or pseudo-hydrolysis to trim down the structurally diverse and complex glycosides into five types of aglycone ions, which were then analyzed using multiple reaction monitoring (MRM). Characteristic product ions were selected based on the aglycone skeleton and substitution pattern and associated fragmentation pathway. RESULTS: A compact method with only 15 MRM transitions were developed for high-throughput screening of very diverse glycoalkaloids. Glycosides of the same aglycone type were readily identified in the same transition window without the need for mass spectra interpretation. Validated using solamargine, the sole available standard, the accuracy was 99.7-101.3%, the intra- and inter-day precision were, respectively, 2.5-5.0% and 8.0-9.2%, and the lower limit of detection and quantification were, respectively, 3.1 and 10.2 ng/mL (with 1 µL injection volume). CONCLUSIONS: The peudo-MS3 method allowed for high-throughput targeted analysis with compact MRM transitions to address a large number of glycoalkaloids with diverse structures. This method could serve to meet the most heavy-duty demand for rapid inspection of glycoalkaloids in SNBs. This method can be adopted and used by those involved in food safety and forensics, in developing food and industrial products and in genetics and breeding.

Influence of Diet-Induced Obesity on the Bioavailability and Metabolism of Raspberry Ketone (4-(4-Hydroxyphenyl)-2-Butanone) in Mice.

OBJECTIVES: Raspberry ketone (RK) is the primary aroma compound in red raspberries and a dietary supplement for weight loss. This work aims to 1) compare RK bioavailability in male versus female, normal-weight versus obese mice; 2) characterize RK metabolic pathways. METHODS: Study 1: C57BL/6J male and female mice fed a low-fat diet (LFD; 10% fat) receive a single oral gavage dose of RK (200 mg kg-1 ). Blood, brain, and white adipose tissue (WAT) are collected over 12 h. Study 2: Male mice are fed a LFD or high-fat diet (45% fat) for 8 weeks before RK dosing. Samples collected are analyzed by UPLC-MS/MS for RK and its metabolites. RESULTS: RK is rapidly absorbed (Tmax  ≈ 15 min), and bioconverted into diverse metabolites in mice. Total bioavailability (AUC0-12 h ) is slightly lower in females than males (566 vs 675 nmol mL-1 min-1 ). Total bioavailability in obese mice is almost doubled that of control mice (1197 vs 679 nmol mL-1 min-1 ), while peaking times and elimination half-lives are delayed. Higher levels of RK and major metabolites are found in WAT of the obese than normal-weight animals. CONCLUSIONS: RK is highly bioavailable, rapidly metabolized, and exhibits significantly different pharmacokinetic behaviors between obese and control mice. Lipid-rich tissues, especially WAT, can be a direct target of RK.

Simultaneous quantification of polyphenols, glycoalkaloids and saponins in African nightshade leaves using ultra-high performance liquid chromatography tandem mass spectrometry with acid assisted hydrolysis and multivariate analysis.

This study developed comprehensive quantification methods for major nutritive and antinutritive phytochemical aglycones in edible African nightshade leaves, an underutilized food resource in the sub-Saharan area. A simultaneous hydrolysis and extraction method was developed using methanol with 2 M sulfuric acid with incubation at 65 °C for 60 min. UHPLC-QqQ-MS/MS methods were developed and validated for hydrolysis optimization and for quantification of eight major aglycones of polyphenols, alkaloids and sapogenins in 20 differently sourced nightshade leaves, comprising two African species Solanum scabrum and S. nigrum, and from two distinct cultivation sites, one in New Jersey, US and the other in Kenya Eldoret. Variation in species, accessions and cultivation environment played an important role in affecting the phytochemical profile. Total antinutritive alkaloids and sapogenins in all nightshade leaves were evaluated and found to be safe for consumption. This work provides evidence that the consumption of African nightshade leaves as a nutrient rich leafy green vegetable is safe and can contribute to food security and nutritional improvement in the sub-Saharan area.

Pine Bark Polyphenolic Extract Attenuates Amyloid-ß and Tau Misfolding in a Model System of Alzheimer's Disease Neuropathology.

Plant-derived polyphenolic compounds possess diverse biological activities, including strong anti-oxidant, anti-inflammatory, anti-microbial, and anti-tumorigenic activities. There is a growing interest in the development of polyphenolic compounds for preventing and treating chronic and degenerative diseases, such as cardiovascular disorders, cancer, and neurological diseases including Alzheimer's disease (AD). Two neuropathological changes of AD are the appearance of neurofibrillary tangles containing tau and extracellular amyloid deposits containing amyloid-ß protein (Aß). Our laboratory and others have found that polyphenolic preparations rich in proanthocyanidins, such as grape seed extract, are capable of attenuating cognitive deterioration and reducing brain neuropathology in animal models of AD. Oligopin is a pine bark extract composed of low molecular weight proanthocyanidins oligomers (LMW-PAOs), including flavan-3-ol units such as catechin (C) and epicatechin (EC). Based on the ability of its various components to confer resilience to the onset of AD, we tested whether oligopin can specifically prevent or attenuate the progression of AD dementia preclinically. We also explored the underlying mechanism(s) through which oligopin may exert its biological activities. Oligopin inhibited oligomer formation of not only Aß1-40 and Aß1-42, but also tau in vitro. Our pharmacokinetics analysis of metabolite accumulation in vivo resulted in the identification of Me-EC-O-ß-Glucuronide, Me-(±)-C-O-ß-glucuronide, EC-O-ß-glucuronide, and (±)-C-O-ß-glucuronide in the plasma of mice. These metabolites are primarily methylated and glucuronidated C and EC conjugates. The studies conducted provide the necessary impetus to design future clinical trials with bioactive oligopin to prevent both prodromal and residual forms of AD.

Phenolic-enriched raspberry fruit extract (Rubus idaeus) resulted in lower weight gain, increased ambulatory activity, and elevated hepatic lipoprotein lipase and heme oxygenase-1 expression in male mice fed a high-fat diet.

Red raspberries (Rubus idaeus) contain numerous phenolic compounds with purported health benefits. Raspberry ketone (4-(4-hydroxyphenyl)-2-butanone) is a primary raspberry flavor phenolic found in raspberries and is designated as a synthetic flavoring agent by the Food and Drug Administration. Synthetic raspberry ketone has been demonstrated to result in weight loss in rodents. We tested whether phenolic-enriched raspberry extracts, compared with raspberry ketone, would be more resilient to the metabolic alterations caused by an obesogenic diet. Male C57BL/6J mice (8 weeks old) received a daily oral dose of vehicle (VEH; 50% propylene glycol, 40% water, and 10% dimethyl sulfoxide), raspberry extract low (REL; 0.2 g/kg), raspberry extract high (REH; 2 g/kg), or raspberry ketone (RK; 0.2 g/kg). Coincident with daily dosing, mice were placed on a high-fat diet (45% fat). After 4 weeks, REH and RK reduced body weight gain (approximately 5%-9%) and white adipose mass (approximately 20%) compared with VEH. Hepatic gene expression of heme oxygenase-1 and lipoprotein lipase was upregulated in REH compared with VEH. Indirect calorimetry indicated that respiratory exchange ratio (CO2 production to O2 consumption) was lower, suggesting increased fat oxidation with all treatments. REH treatment increased total ambulatory behavior. Energy expenditure/lean mass was higher in REH compared with REL treatment. There were no treatment differences in cumulative intake, meal patterns, or hypothalamic feed-related gene expression. Our results suggest that raspberry ketone and a phenolic-enriched raspberry extract both have the capacity to prevent weight gain but differ in the preventative mechanisms for excess fat accumulation following high-fat diet exposure.

Repellency Assessment of Nepeta cataria Essential Oils and Isolated Nepetalactones on Aedes aegypti.

There is an increased need for improved and affordable insect repellents to reduce transmission of rapidly spreading diseases with high mortality rates. Natural products are often used when DEET cannot be afforded or accessed and when consumers choose not to use a synthetic repellent. The essential oils from two newly bred Nepeta cataria (catnip) plants representing two different chemotypes and their respective isolated nepetalactone isomers were evaluated as mosquito repellents against Aedes aegypti mosquitoes that transmit the Zika and Dengue virus in a one choice landing rate inhibition assay. A dose response curve was generated for each treatment and a time course analysis of repellency was performed over 24 hours with a N. cataria essential oil sample. The results indicate that all essential oil samples and their respective purified nepetalactone isomers were able to achieve greater than 95% repellency. Between two and four hours, the ability to repel more than 95% of the mosquitoes diminished. At the lowest concentrations tested, the nepetalactones and crude essential oil samples were more effective than DEET at reducing the number of mosquito landings.

Identification of Polyphenols, Glycoalkaloids, and Saponins in Solanum scabrum Berries Using HPLC-UV/Vis-MS.

Consumption safety of Solanum scabrum berries is controversial in different cultural practices and evaluation of the toxicity as well as micronutrition value relies on relevant phytochemical study. Thus, this study aimed to systematically profile the phytochemicals in the berries from different genetic sources and maturity. Using a combination of three different and complementary methods of HPLC-UV/Vis-MS or MS/MS with acid-assisted hydrolysis, a total of 54 phytochemicals were identified including polyphenols, saponins and toxic glycoalkaloids. Particularly, a broad range of glycoalkaloids of solasodine and its uncommon or potentially novel hydroxylated and methylated derivatives were reported, with the structure putatively identified based on the known scaffold-fragmentation pattern. Other identified phytochemicals included phenolic acids of chlorogenic acid and neochlorogenic acid, flavonol glycosides of quercetin and isorhamnetin, anthocyanins of petunidin, malvidin and delphinidin, and saponins of diosgenin and tigogenin. PRACTICAL APPLICATION: This study provides solutions for identifying the phytochemicals of S. scabrum berries, and unveiled for the first time a wide range of toxic glycoalkaloids of solasodine and analogues in the berries from different genetic sources and maturation stages. This work laid the foundation for prospective quantitative determination of berry phytochemicals and future toxicity and nutrition evaluation, and could also apply to facilitate screening or breeding for glycoalkaloid-deficient genotypes that can be used as new food supply.

Quantity assessment of polyphenols, glycoalkaloids and saponins in Solanum scabrum berries of different genetic sources and maturity by HPLC/UV-visible/MS methods.

BACKGROUND: Solanum scabrum berries in sub-Saharan Africa are prolific but neglected as an agricultural resource. Recognition and application of such underutilized resources rely on systematic study of the relevant phytochemicals of commercial value. RESULTS: The quantities of a total of 54 phytochemicals in Solanum scabrum berries were assessed using HPLC-MS methods. Berries from eight different genetic sources were analyzed with two entries monitored across different maturation stages. There was a significant variation among mature berries in the accumulation of phenolic acids, 91.5-794 mg·100 g-1 dry weight (DW); flavonols, 76.3-897 mg·100 g-1 DW; anthocyanins, 178-4650 mg·100 g-1 DW; glycoalkaloids, 1.76-1630 mg·100 g-1 DW; and saponins, 82.2-606 mg·100 g-1 DW. Fruit development from immature to post-frost harvest featured dynamic changes in phytochemical composition and, despite remarkable differences in the absolute magnitude of content, the trend of change was generally similar in different genetic sources. CONCLUSIONS: The genotype-dependent difference in toxic glycoalkaloids in mature berries may partially explain the consumption controversy as it reflects glycoalkaloid content. The analytical methods applied in this work should serve for quality control of glycoalkaloids thereby improving the safe utilization of this berry. In addition, the selection and breeding of new genotypes with low and safe levels of glycoalkaloids and saponins in the berry could be of value in sub-Saharan Africa to increase nutrition and generate new income opportunities for growers. © 2019 Society of Chemical Industry.

Bioactive polyphenols in kinkéliba tea (Combretum micranthum) and their glucose-lowering activities.

Herbal tea kinkéliba prepared from the leaves of Combretum micranthum has been widely consumed in West African countries for its flavor, nutritional and medicinal properties. Under bio-guided screening, the kinkéliba leaves were chemically investigated using various chromatographic and spectrometric methods that led to the identification of thirteen different flavonoid compounds. Further biological tests illustrated that the identified compounds may have synergistic effects to decrease the expression of phosphoenolpyruvate carboxykinase (PEPCK) mRNA and glucose production in an H4IIE hepatoma cell line, indicating its potential use for insulin-resistant diabetes treatment. Further in vivo study on C57BL/6J mice indicates that kinkéliba can lower plasma glucose levels in a dose-dependent manner without significant weight loss and toxicity. The ethyl acetate extract in rich of flavonoids could also increase the glucose tolerance (GT) after seven weeks' administrations. Both in vitro and in vivo experiments support a potential new application of kinkéliba leaves as an anti-diabetes agent.

Rapid screening of toxic glycoalkaloids and micronutrients in edible nightshades (Solanum spp.).

African indigenous vegetables (AIVs) because of their nutrient density have the unique potential to reduce micronutrient deficiencies in sub-Saharan Africa, yet some may also contain anti-nutritive compounds. Vegetable nightshades from Solanum americanum, Solanum nigrum, Solanum scabrum and Solanum villosum are among the major AIVs used as a leafy vegetables and consumed regularly in many countries in sub-Sahara Africa. These under-recognized food crops have not been subjected to extensive studies for their nutritional and antinutritive factors. In this study, 15 entries of the vegetable nightshades were field-grown and the leaves which are the consumed product of commerce chemically profiled by LC/ESI-MS. Twenty-three flavones, eight saponins, and two glycoalkaloids along with a phenolic acid of chlorogenic acid were identified by MS and UV data. Anti-nutrient glycoalkaloids were quantified as total aglycones after acidic hydrolysis using MS detection and found to be within safe-consumption thresholds by comparison with the glycoalkaloid level in the globally consumed Solanum member eggplants. Edible nightshades were also found to be sources of ß-carotene, vitamin E and total polyphenols and exhibited high antioxidant activity. Results of this study support that consumption of vegetable nightshades are safe from the presence of glycoalkaloids and thus, can contribute to the reduction of micronutrient deficiency in sub-Sahara Africa.

Influence of diabetes on plasma pharmacokinetics and brain bioavailability of grape polyphenols and their phase II metabolites in the Zucker diabetic fatty rat.

SCOPE: The effect of diabetes on the pharmacokinetics, bioavailability and brain distribution of grape polyphenols and select metabolites was studied in the Zucker diabetic fatty (ZDF) rat model. METHODS AND RESULTS: (ZDF) rats and their lean controls (LN) were dosed with a Standardized Grape Polyphenol (SGP) Mixture consisting of grape seed extract, Concord grape juice and resveratrol (RES) by oral gavage for 10 days. An 8-h pharmacokinetic study was performed. After 24 h, a second dose of SGP was administered and 1 h later animals were sacrificed and brain tissue was harvested. Plasma, urine, and brain tissue were analyzed for grape polyphenols. ZDF rats exhibited significantly diminished Cmax for all catechin, epicatechin, quercetin and resveratrol conjugated metabolites. Bioavailability was significantly lower in ZDF rats for methylated flavan-3-ol, RES, and quercetin metabolites. Significantly lower levels of metabolites of RES, quercetin, and flavan-3-ols were found in brains of ZDF rats. There was no significant difference between ZDF and LN in anthocyanins in plasma and no anthocyanins were detectable in brain extracts. ZDF rats showed significantly higher urinary excretion for all polyphenols. CONCLUSION: Diabetes may alter the overall bioavailability of some polyphenols in plasma and brain in part due to higher urinary clearance.

Phytochemical Analysis and Anti-Inflammatory Activity of the Extracts of the African Medicinal Plant Ximenia caffra.

A method was developed for identification and quantification of polyphenols in the leaves of Ximenia caffra using HPLC/UV/MS. Based on analyzing the MS and UV data and in comparison to the authentic standards, a total of 10 polyphenols were identified and quantified, including gallic acid, catechin, quercetin, kaempferol, and their derivatives. The total content of these compounds was found to be approximately 19.45 mg/g in the leaf and the most abundant is quercetin-rutinoside (9.08 mg/g). The total phenolic content as measured by Folin-Ciocalteu assay was 261.87 ± 7.11 mg GAE/g and the total antioxidant capacity as measured in vitro was 1.46 ± 0.01 mmol Trolox/g. The antiproliferative effect of the leaf extract was measured by MTS assay with IC50 value of 239.0 ± 44.5 µg/mL. Cell-based assays show that the leaf extract inhibits the mRNA expression of proinflammatory genes (IL-6, iNOS, and TNF-α) by using RT-qPCR, implying its anti-inflammatory effects. It was further demonstrated that the underlying therapeutic mechanism involves the suppression of NF-κB, a shared pathway between cell death and inflammation.

Chemical investigation of commercial grape seed derived products to assess quality and detect adulteration.

Fundamental concerns in quality control arise due to increasing use of grape seed extract (GSE) and the complex chemical composition of GSE. Proanthocyanidin monomers and oligomers are the major bioactive compounds in GSE. Given no standardized criteria for quality, large variation exists in the composition of commercial GSE supplements. Using HPLC/UV/MS, 21 commercial GSE containing products were purchased and chemically profiled, major compounds quantitated, and compared against authenticated grape seed extract, peanut skin extract, and pine bark extract. The antioxidant capacity and total polyphenol content for each sample was also determined and compared using standard techniques. Nine products were adulterated, found to contain peanut skin extract. A wide degree of variability in chemical composition was detected in commercial products, demonstrating the need for development of quality control standards for GSE. A TLC method was developed to allow for rapid and inexpensive detection of adulteration in GSE by peanut skin.

Neuroprotective effects of anthocyanin- and proanthocyanidin-rich extracts in cellular models of Parkinson׳s disease.

Neuropathological evidence indicates that dopaminergic cell death in Parkinson׳s disease (PD) involves impairment of mitochondrial complex I, oxidative stress, microglial activation, and the formation of Lewy bodies. Epidemiological findings suggest that the consumption of berries rich in anthocyanins and proanthocyanidins may reduce PD risk. In this study, we investigated whether extracts rich in anthocyanins, proanthocyanidins, or other polyphenols suppress the neurotoxic effects of rotenone in a primary cell culture model of PD. Dopaminergic cell death elicited by rotenone was suppressed by extracts prepared from blueberries, grape seed, hibiscus, blackcurrant, and Chinese mulberry. Extracts rich in anthocyanins and proanthocyanidins exhibited greater neuroprotective activity than extracts rich in other polyphenols, and a number of individual anthocyanins interfered with rotenone neurotoxicity. The blueberry and grape seed extracts rescued rotenone-induced defects in mitochondrial respiration in a dopaminergic cell line, and a purple basal extract attenuated nitrite release from microglial cells stimulated by lipopolysaccharide. These findings suggest that anthocyanin- and proanthocyanidin-rich botanical extracts may alleviate neurodegeneration in PD via enhancement of mitochondrial function.