Marcia Da Silva Pinto

Functionality of Bioactive Compounds in Brazilian Strawberry (Fragaria × ananassa Duch.) Cultivars: Evaluation of Hyperglycemia and Hypertension Potential Using in Vitro Models

Fruits of seven fully ripened strawberry cultivars grown in Brazil (Dover, Camp Dover, Camarosa, Sweet Charlie, Toyonoka, Oso Grande, and Piedade) were evaluated for total phenolics, antioxidant activity based on DPPH radical scavenging assay, and functionality such as inhibition of alpha-amylase, alpha-glucosidase, and angiotensin I-converting enzyme (ACE) relevant for potentially managing hyperglycemia and hypertension. The total phenolics content ranged from 966 to 1571 microg of gallic acid/g of fruit fresh weight for Toyonoka and Dover, respectively. No correlation was found between total phenolics and antioxidant activity. The major phenolic compounds in aqueous extracts of strawberries were ellagic acid, quercetin, and chlorogenic acid. Strawberries had high alpha-glucosidase inhibitory activity. However, alpha-amylase inhibitory activity was very low in all cultivars. This suggested that strawberries could be considered as a potential dietary source with anti-hyperglycemic potential. The evaluated cultivars had no significant ACE inhibitory activity, reflecting low anti-hypertensive potential.

Evaluation of Antiproliferative, Anti-Type 2 Diabetes, and Antihypertension Potentials of Ellagitannins from Strawberries (Fragaria × ananassa Duch.) Using In Vitro Models

Strawberries represent the main source of ellagic acid derivatives in the Brazilian diet, corresponding to more than 50% of all phenolic compounds found in the fruit. There is a particular interest in the determination of the ellagic acid content in fruits because of possible chemopreventive benefits. In the present study, the potential health benefits of purified ellagitannins from strawberries were evaluated in relation to the antiproliferative activity and in vitro inhibition of α-amylase, α-glucosidase, and angiotensin I-converting enzyme (ACE) relevant for potential management of hyperglycemia and hypertension. Therefore, a comparison among ellagic acid, purified ellagitannins, and a strawberry extract was done to evaluate the possible synergistic effects of phenolics. In relation to the antiproliferative activity, it was observed that ellagic acid had the highest percentage inhibition of cell proliferation. The strawberry extract had lower efficacy in inhibiting the cell proliferation, indicating that in the case of this fruit there is no synergism. Purified ellagitannins had high α-amylase and ACE inhibitory activities. However, these compounds had low α-glucosidase inhibitory activity. These results suggested that the ellagitannins and ellagic acid have good potential for the management of hyperglycemia and hypertension linked to type 2 diabetes. However, further studies with animal and human models are needed to advance the in vitro assay-based biochemical rationale from this study.

Antioxidant Status in Humans after Consumption of Blackberry (Rubus fruticosus L.) Juices With and Without Defatted Milk

The present study was designed to evaluate the possible effect of the consumption of blackberry juices (BJ) prepared with water (BJW) and defatted milk (BJM) on the plasma antioxidant capacity and the enzymatic and nonenzymatic antioxidants. A significant (p < 0.05) increase in the ascorbic acid content in the plasma was observed after intake of both BJs. However, no changes were observed in the plasma urate and alpha-tocopherol levels. An increase on the plasma antioxidant capacity, by ORAC assay, was observed only after consumption of BJW but not statistically significant. Plasma antioxidant capacity had a good positive correlation with ascorbic acid (r = 0.93) and a negative correlation with urate level (r = -0.79). No correlation was observed between antioxidant capacity and total cyanidin or total ellagic acid contents. Further, it was observed that plasma catalase increased following intake of BJs. No change was observed on the plasma and erythrocyte CAT and glutathione peroxidase activities. A significant decrease (p < 0.05) in the urinary antioxidant capacity between 1 and 4 h after intake of both BJs was observed. A good correlation was observed between total antioxidant capacity and urate and total cyanidin levels. These results suggested association between anthocyanin levels and CAT and a good correlation between antioxidant capacity and ascorbic acid in the human plasma after intake of BJs. Follow-up studies investigating the antioxidant properties and health benefits are necessary to demonstrate the health benefits of polyphenols.

Evaluation of Antihyperglycemia and Antihypertension Potential of Native Peruvian Fruits Using In Vitro Models

Local food diversity and traditional crops are essential for cost-effective management of the global epidemic of type 2 diabetes and associated complications of hypertension. Water and 12% ethanol extracts of native Peruvian fruits such as Lucuma (Pouteria lucuma), Pacae (Inga feuille), Papayita arequipeña (Carica pubescens), Capuli (Prunus capuli), Aguaymanto (Physalis peruviana), and Algarrobo (Prosopis pallida) were evaluated for total phenolics, antioxidant activity based on 2, 2-diphenyl-1-picrylhydrazyl radical scavenging assay, and functionality such as in vitro inhibition of alpha-amylase, alpha-glucosidase, and angiotensin I-converting enzyme (ACE) relevant for potential management of hyperglycemia and hypertension linked to type 2 diabetes. The total phenolic content ranged from 3.2 (Aguaymanto) to 11.4 (Lucuma fruit) mg/g of sample dry weight. A significant positive correlation was found between total phenolic content and antioxidant activity for the ethanolic extracts. No phenolic compound was detected in Lucuma (fruit and powder) and Pacae. Aqueous extracts from Lucuma and Algarrobo had the highest alpha-glucosidase inhibitory activities. Papayita arequipeña and Algarrobo had significant ACE inhibitory activities reflecting antihypertensive potential. These in vitro results point to the excellent potential of Peruvian fruits for food-based strategies for complementing effective antidiabetes and antihypertension solutions based on further animal and clinical studies.

Inhibitory potential of tea polyphenolics and influence of extraction time against Helicobacter pylori and lack of inhibition of beneficial lactic acid bacteria.

Tea polyphenolics such as catechins are known to have the potential to inhibit many bacterial pathogens. Helicobacter pylori has been identified as an etiologic agent in the development of gastric ulcer, peptic ulcer, gastritis, and many other stomach-related diseases. In this study, we investigated the effect of 9 tea extracts--3 different brands representing 4 different processed types (white, green, oolong, and black)--on the inhibition of H. pylori. Extraction times of 2 and 5 minutes were compared. Most 5-minute extracts showed H. pylori inhibition, whereas 2-minute extracts only of Choice darjeeling black and Tazo white showed inhibition. No recovery was observed after the addition of 0.5 and 5 mM proline, indicating that tea polyphenols do not inhibit H. pylori by inhibition of proline oxidation via proline dehydrogenase. Extracts that showed inhibition were further evaluated for their effect on beneficial lactic acid bacteria. None of the samples showed inhibition, suggesting that tea might be able to inhibit H. pylori without affecting the beneficial lactic acid bacteria. High-performance liquid chromatography indicated the presence of gallic acid, quercetin, caffeine, and tea catechins (including catechin, epicatechin, and epigallocatechin) in all the tea samples. Our study indicates that tea can be potentially used as a low-cost dietary support to combat H. pylori-linked gastric diseases without affecting the beneficial intestinal bacteria.

Phenolic-linked biochemical rationale for the anti-diabetic properties of Swertia chirayita (Roxb. ex Flem.) Karst.

The crude extract of Swertia chirayita, an important medicinal plant of Nepal, is locally used for many diseases including type 2 diabetes. In this study, crude aqueous and 12% ethanol solution extracts of S. chirayita collected from nine districts of Nepal were analyzed for anti‐diabetic‐linked anti‐hyperglycemia potential using in vitro biochemical assays. There was moderate‐to‐high positive correlation between antioxidant activity and total phenolic content of both extracts and moderate‐to‐high α‐glucosidase inhibitory activity. Although the anti‐diabetic property of S. chirayita is mainly attributed to the phytochemical swerchirin present in its hexane fraction, we propose that the crude extract of this plant used in local healing also has anti‐hyperglycemia potential. The crude extracts indicated the presence of three main phytochemicals mainly mangiferin, swertiamarin, and amarogentin and their derivatives. Among the standard compounds (mangiferin, swertiamarin, and amarogentin), mangiferin showed α‐glucosidase and 2,2‐diphenyl‐1‐picrylhydrazyl radical inhibitory activity indicating anti‐hyperglycemia potential. Copyright

Potential of Cranberry Powder for Management of Hyperglycemia Using In Vitro Models

Aqueous solutions of two different cranberry powders (CP and CP-SAB) were evaluated for organic acids, sugars, total phenolics, antioxidant activity based on the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, and functionality such as in vitro inhibition of α-amylase, α-glucosidase, and angiotensin I-converting enzyme (ACE) relevant for potential management of hyperglycemia and hypertension linked to type 2 diabetes. The total phenolics content was 11 and 51 mg/g of sample dry weight for CP and CP-SAB, respectively. p-Coumaric acid and quercetin derivatives were the main phenolic compounds identified in the cranberry powders. CP-SAB had α-glucosidase inhibitory activity that increased with increased dose (1-5 mg/mL) from 60% to 100% inhibition. There was limited amount of α-amylase inhibitory activity that reached a maximum of 40% inhibition at 5 mg/mL treatment. Significant ACE inhibitory activity was detected for CP-SAB at 100 and 200 mg/mL sample concentrations. These in vitro results indicate the potential of cranberry powders as dietary supplement and food-based strategies for potential hyperglycemia management. This biochemical rationale provides the basis for further design of animal and clinical studies using standardized extracts.

Varietal influences on antihyperglycemia properties of freshly harvested apples using in vitro assay models.

The well-known health benefits of apples have been attributed in part to the presence of polyphenols and related antioxidant capacity. The consumption of apples could provide health benefits by reducing the risk for chronic diseases such as metabolic syndrome disease, including type 2 diabetes. Thus, the objective of this study was to investigate the phenolic-linked antihyperglycemia bioactive factors in aqueous and 12% ethanol extracts of peel and pulp from 10 different freshly harvested apple varieties commonly consumed in the United States. The extracts were analyzed for total soluble phenolics, 2,2-diphenyl-1-picrylhydrazyl-linked antioxidant activity, and their associated in vitro α-glucosidase and α-amylase inhibitory activities. In general, peel extracts had higher total soluble phenolic content and related antioxidant capacity than pulp extracts. Quercetin derivatives, protocatechuic acid, chlorogenic acid, and p-coumaric acid were detected, and the amount varied significantly between aqueous and ethanolic extracts. Honeycrisp and Red Delicious varieties had the highest total phenolic contents and a significant correlation with antioxidant capacity (r = 0.91). In addition, high α-amylase and α-glucosidase inhibitory activities in aqueous pulp extracts were found. However, the peel extracts had the highest α-glucosidase inhibitory activity along with low α-amylase inhibitory activity. No correlation between α-amylase inhibitory activity and total phenolic content was observed. However, positive correlations between α-glucosidase inhibitory activity and total phenolics in aqueous (r = 0.50) and ethanolic (r = 0.70) extracts were observed. This study provides the biochemical rationale for animal and clinical studies to determine the suitable varieties with optimum bioactive factors with antihyperglycemia potential.

Phenolic Bioactive Modulation by Lactobacillus acidophilus Mediated Fermentation of Cherry Extracts for Anti-Diabetic Functionality, Helicobacter pylori inhibition and Probiotic Bifidobacterium longum Stimulation

Cherry juice from one cultivar was fermented for 0, 24, 48, and 72 h using Lactobacillus acidophilus, and its effects related to management of hyperglycemia, hypertension, inhibition of Helicobacter pylori, and proliferation of probiotic Bifidobacterium longum were evaluated using in vitro models. Cherry extract was fermented by initially adjusting the pH to 6.0 and at the natural acidic pH. Analysis was carried out by adjusting the pH and at fermented acidic pH at each time point from each of the two samples. Total soluble phenolics decreased over a period of 72 h for initial pH adjusted samples whereas it increased or remained constant for natural acidic pH samples. DPPH linked antioxidant activity and α-glucosidase inhibitory activity decreased for samples where final pH was adjusted whereas it increased for natural acidic pH samples. Fermentation led to a decrease in hypertension-relevant ACE inhibitory activity for all samples. Natural acidic pH samples had Helicobacter pylori inhibitory activity at 24, 48 and 72 h. Based on the rationale that simple phenolics in cherry could behave as proline analogs, the potential recovery of the pathogen from inhibition was evaluated with of addition of 0.5 mM proline in the medium. A proline induced growth recovery was observed indicating that the mechanism of inhibition is related to proline dehydrogenase based oxidative phosphorylation. Overall, no inhibition was observed when samples that had H. pylori inhibitory activity were further evaluated for their effect on probiotic Bifidobacterium longum.

Targeted Screening and Improvement of the Medicinal Properties of Oregano and Rhodiola with Chitosan Oligosaccharide and Vitamin C Using in Vitro Assays for Hyperglycemia and Hypertension Linked to Type 2 Diabetes

ABSTRACT The aim of this study was to improve antioxidant-linked bioactive properties in oregano and rhodiola, by combination with chitosan oligosaccharide (COS) or vitamin C. Phenolic antioxidant–linked functionalities of these herbs in combination with COS or vitamin C were evaluated using in vitro assays. Combinations of COS separately with each herb enhanced antioxidant activity (3–7%), while combination of vitamin C with oregano improved α-glucosidase enzyme inhibition (1–10%) associated with type 2 diabetes. The improvement of angiotensin-converting enzyme (ACE) inhibition in both herbs was confirmed when combined separately with vitamin C (40–50%) and may be targeted against associated hypertension.