Changes in polyphenols content and biological activities on Tetrapleura tetraptera and Aframomum citratum fruits extracts using different extraction methods in an acid/alkaline medium

Objective: To investigate some phytochemical constituents and biological activities of twelve samples of Tetrapleura tetraptera (Schumach & Thonn.) taub. and nine samples of Aframomum citratum (C. Pereira) K. Schum fruits collected in the bimodal forest zone (ZONE V), the unimodal forest zone (ZONE IV) and the highlands zone (ZONE III) in Cameroon. Methods: Fresh fruits extracts were obtained by aqueous infusion (100 °C during 15 min) and evaluated by spectrophotometric methods for total polyphenol (TPP), total flavonoids (TFLV) contents and antioxidant (DPPH, total antioxidant capacity by the phosphomolybdenum method, iron reducing power or ferric reducing antioxidant power and inhibition of beta carotene discoloration assays) and anti-inflammatory (inhibitions of protein denaturation and 5-LOX represented by INH.PROT and INH.5- LOX respectively) properties. Principal component analysis was performed. Results: For both species, fruits from ZONE V have the highest TPP, TFLV levels and biological activities. TPP and TFLV content of Aframomum citratum and Tetrapleura tetraptera fruits are positively and significantly (P Conclusions: The fruits exhibit variabilities and those from ZONE V for both species are economically and healthcare challenging for herbalists, pharmaceutical firms, scientists and consumers. Indeed, most important extraction yield of bioactive compounds correlated with significant biological activities and the use of less material compared with an implementation in other Agro-ecologic Zones with the same results are noted.

Polyphenols with antioxidant compounds represent an important group of bioactive substances in apple production. The objectives of this study were firstly to measure four parameters of antioxidant capacity (AC) and polyphenol content (AC-FRAP (Ferric Reducing Ability of Plasma), AC-DPPH (2,2-diphenyl-1-picrylhydrol), AC-TEAC (Trolox Equivalent Antioxidant Capacity) and total polyphenol content (TPC)) of four scab-resistant apple cultivars (‘Fujion’, ‘Gaia’, ‘Isaaq’ and ‘Smeralda’) using six extraction methods (water control, pectinase, two approaches using ethanol (EtOH-1 and EtOH-2), methanol (MetOH) and methanol + acetone (MetOH + Acetone), and secondly to provide intercorrelations between antioxidant and polyphenol contents of the four resistant apple cultivars under the six extraction methods. Analysis of variance on the four parameters showed a significant (p = 0.05) effect for extraction methods and cultivars. TPC showed the highest values among the four parameters in all extraction methods and cultivars compared to the other three measurements. The pectinase extraction method showed the highest TPC values for the four cultivars. The EtOH-2 extraction method showed the lowest AC-FRAP value for all cultivars. The EtOH-2 extraction method showed the highest AC-DPPH values, whereas the control method showed the lowest values for the four cultivars. The AC-TEAC values were generally the lowest, ranging between 10.8 and 40.5 mg TE 100 g−1 dry matter, and they showed various effects on extraction methods and cultivars. Correlation and regression analyses of 36 pair-variables showed that two pair-variables (TPC vs. AC-FRAP and AC-TEAC vs. AC-DPPH) were significant for all of the six extraction methods and for all cultivars. In conclusion, the extraction method using pectinase enzyme provided the most stable yield of polyphenol content from apple flesh, as confirmed by the examination of four scab-resistant apple cultivars.

Commercially available tea infusions are the major source of catechins for preparing bottled tea beverages and tea supplements available in the market today. In the present study, we analyzed five tea infusions to measure the total antioxidant capacity (TAC) by oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity (DRSC) assays, total polyphenol content by the colorimetric method and individual catechin content by high-performance liquid chromatography. Four major tea catechins were also analyzed for their TAC to reveal differential antioxidant behavior of the tea infusions, resulting in the ORAC and DRSC methods. The correlation coefficients between DRSC and the total polyphenol or total catechin content of the tea infusions were 1.0 and 0.99. However, the values fall to 0.73 and 0.69, respectively, while the ORAC activity was correlated with total polyphenol and total catechin content. Determining the TAC of individual tea catechins showed that ORAC of epicatechin was seven-fold higher than that of epigallocatechin gallate; on the contrary, epigallocatechin gallate showed significantly (P < 0.05) stronger DRSC activity than epicatechin. By evaluating the structure−activity relationship, this study further revealed that OH substitution at the 3′ position in pyrogallol moieties contributes to the lower ORAC value of epigallocatechin and epigallocatechin gallate comparing with their non-3′-OH counterparts, such as epicatechin and epicatechin gallate, respectively. Also, numbers of OH substitutions were poorly correlated with the observed ORAC value unlike the DRSC. Overall, results of this study enabled us to hypothesize that substances having a lower TAC value in the ORAC assay compared with that in DPPH assays may pertain to a pro-oxidant effect by generating reactive oxygen species in an aqueous buffer, at a physiological pH. We also propose that substances exhibiting lower TAC value in the ORAC assay compared with that in the DPPH assay are powerful pro-oxidants compared with the substances showing a higher TAC value in the ORAC assay than that in the DPPH assay.

The total antioxidant potential of a sample cannot be predicted from the antioxidant activity of its compounds; thus, scientists usually explain the overall activity through their combined effects (synergistic, antagonistic, or additive). Phenolic compounds are one of the most powerful and widely investigated antioxidants, but there is a lack of information about their molecular interactions. This study aimed to investigate the individual and combined antioxidant activity of equimolar mixtures (binary, ternary, quaternary, and quinary) of 10 phenolic acids (protocatechuic, gentisic, gallic, vanillic, syringic, p-coumaric, caffeic, ferulic, sinapic, and rosmarinic acid) at different concentrations using ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. Gallic acid showed the highest antioxidant activity, determined using the FRAP assay (494–5033 µM Fe2+) and rosmarinic acid with the ORAC assay (50–92 µM Trolox Equivalents (TE)), while the lowest antioxidant potential was observed for p-coumaric acid (FRAP 24–113 µM Fe2+ and ORAC 20–33 µM TE). The synergistic effect (by FRAP) in the equimolar mixtures of hydroxybenzoic acids was confirmed for a large number of tested mixtures, especially at low concentrations. All mixtures containing gentisic acid showed a synergistic effect (28–89% difference). Using the ORAC method, only two mixtures of hydroxybenzoic acids showed an antagonistic effect, namely a mixture of gentisic + syringic acids (−24% difference) and gallic + vanillic acids (−30% difference), while all other mixtures showed a synergistic effect in a range of 26–236% difference. Among mixtures of hydroxycinnamic acids, the highest synergistic effect was observed for the mixtures of p-coumaric + ferulic acids and caffeic + sinapic acids with differences of 311% and 211%, respectively. The overall antioxidant activity of phenolic acids could be explained by the number or position of hydroxyl and/or methoxy functional groups as well as the compound concentration, but the influence of other parameters such as dissociation, intramolecular hydrogen bonds, and electron donating or withdrawing effect should not be neglected.

Changes in the structure of polysaccharides under different extraction methods

In this study, the total polyphenol content (TPC), total flavonoid content (TFC), and biological activity of yam polyphenols (including free phenolics, conjugated phenolics, and bound phenolics) were investigated during home cooking. Polyphenol components were preliminary detected in raw yam by HPLC, including 2, 4-dihydroxybenzoic acid, syringic acid, vanillic acid, 4-coumaric acid, and sinapic acid. TPC and TFC of soluble conjugated polyphenols were the main phenolic compounds in Ruichang yam. Compared with uncooked yam, cooking times of 80 min and 40 min increased the TPC and TFC of multiple types of polyphenols, while cooking reduced the TPC and TFC of AHP (acid-hydrolyzed soluble conjugated polyphenols). All yam polyphenols exhibited good α-Glucosidase inhibitory activity; α-Glucosidase inhibitory activity was significantly higher for a cooking time of 120 min. Only some types of polyphenols had lower pancreatic lipase half-inhibition concentrations than orlistat when cooked. The pancreatic lipase of FPs (free polyphenols), BHPs (alkali-hydrolyzed soluble conjugated polyphenols), and ABPs (acid-hydrolyzed insoluble bound polyphenols) was the stronges when cooking for 80 min, and the pancreatic lipase inhibitory activity of AHPs and BBPs (alkali-hydrolyzed insoluble bound polyphenols) was strongest when cooking for 40 min. Pearson's correlation coefficient analysis revealed that the TPC was positively correlated with the TFC, the IC50 value of α-Glucosidase was negatively correlated with the IC50 value of pancreatic lipase, and redox activity was positively correlated with the TPC and TFC, respectively.

Bioactive Compounds from Mimosa pudica Leaves Extract with Their α- glucosidase and Protein Tyrosine Phosphatase 1B Inhibitory Activities in vitro and in silico Approaches

This study aims to determine the effect of citric acid-glucose based microwave assited extraction (MAE) method on total polyphenols content from (Peperomia pellucida [L.] Kunth) herbs. Dried samples were extracted using green solvent glucose citric acid with a ratio of 1: 1 g/g, 3: 1 g/g, and 5: 1 g/g, respectively, 30% microwave power for 5 minutes, and 1:5 g /mL solid-liquid ratio. Then the obtained extract solution was performed determination total polyphenols content using Folin-Ciocalteu reagent, and the absorbance was measured using a UV-Vis spectrophotometer at 791 nm. Based on the results, obtained total polyphenols content according to the extraction condition namely 214.405 mg GAE/g sample (3: 1 g /g solvent), 84.833 mg GAE /g sample (1: 1 g /g solvent) and 53,9451 mg GAE/g sample (5: 1 g /g solvent), respectively. This study is a preliminary data about the use of citric acid-glucose based microwave assisted extraction method on total polyphenols content from this plant quickly, easily and efficiently.

In the last years the utilization of natural waste for alternative uses gained a lot of interest. The aim of this paper was to analyze the total polyphenols and the fatty acids content of a walnut and a pumpkin meal using two extraction methods. Bioactive compounds were extracted in acetone and methanol for 24 hours. The total phenolic content, antioxidant activity and fatty acids composition was determined in extracts by Folin–Ciocalteu , DPPH assay and gas chromatography. The acetone extracts have higher total polyphenol content and antioxidant capacity. Methanol extraction allowed the extraction of only 39% of the total polyphenols obtained in the acetone extracts. The antioxidant capacity was highly correlated with the total polyphenol contents irrespective of the type of the solvent or of meal. Only palmitic, stearic, oleic and linoleic fatty acids were extracted in acetone, where lauric, miristic, palmitic, palmitoleic, stearic, oleic, linoleic, linolenic acids were found in methanol extracts for both walnuts and pumpkin meals. In conclusion, walnut extracts have a higher content in total polyphenols, fatty acids and have a higher antioxidant activity than pumpkin extracts, in both solvents.

Propolis is a honeybee product with significant biological properties, strongly influenced by geographic and floral origin as well as extraction method. Ultrasound-assisted extraction (UAE) is an emerging alternative for propolis preparation. This study aimed to determine the optimal UAE conditions for total polyphenol content (TPC) and total flavonoid content (TFC) in Chilean propolis and compare its antioxidant and antimicrobial capacities with a conventional method. UAE was performed with varying ethanol concentrations (50-90%), temperatures (20-60 °C), and extraction times (10-50 min), keeping the solid/liquid ratio constant at 1:10 (w/v). The optimal ethanolic UAE extract (OE) was compared to the conventional ethanolic extract (CE) for antimicrobial activity against Salmonella enterica and Listeria monocytogenes and antioxidant capacity (DPPH, ABTS, FRAP assays). Optimal UAE conditions were 80% ethanol, 30 °C, and 30 min. The OE showed significantly higher (p < 0.05) TPC (22.4 ± 0.3 mg GAE/mL), TFC (15.7 ± 0.7 mg QE/mL), antioxidant capacity (ABTS: 35.7 ± 0.9; DPPH: 62.9 ± 0.3; FRAP: 49.7 ± 2.1 µmol TE/mL), and antimicrobial activity in the evaluated Gram-positive bacteria (>15 mm inhibition halo, MBC = 3.1 mg/mL) compared to the CE. The bioaccessibility analysis revealed that the OE maintained 20.1% of its polyphenol content and 69.5%, 60.5%, and 61.9% of DPPH, ABTS, and FRAP, respectively, after simulated gastrointestinal digestion. The established optimal UAE conditions generated extracts with increased polyphenol content, antioxidant capacity, antimicrobial activity, and bioaccessibility, indicating its potential as an extraction method for propolis with enhanced bioactivity.

Hemp, commonly known as Cannabis sativa L., is a medicinal plant species of the Cannabaceae family. For the efficient extraction of C. sativa leaves using the conventional stirring process with water as the solvent, three crucial extraction parameters (i.e., extraction duration, liquid–solid ratio, and temperature) were investigated through the response surface methodology (RSM). The concentrations of the extracted bioactive compounds (polyphenols, ascorbic acid, and carotenoids) showed significant variations in the RSM design points, suggesting the importance of finding the optimal extraction conditions in which liquid–solid ratio and extraction temperature were found to have the highest impact. Further analysis was conducted on the optimal extract employing several assays to determine their polyphenol content, total carotenoid content, color evaluation, anti-inflammatory activity, and antioxidant capacity through FRAP, DPPH, and H2O2 assays. A low extraction time (30 min) at 50 °C and a high liquid–solid ratio (50:1) were required for the highest possible yield of polyphenols. The total polyphenol content was determined to be 9.76 mg gallic acid equivalents/g under optimum conditions, with pelargonin being the most abundant polyphenol (1.51 mg/g) in C. sativa extracts. Ascorbic acid was measured at 282.23 μg/g and total carotenoids at 356.98 μg/g. Correlation analyses revealed that anti-inflammatory activity was negatively correlated with specific polyphenols. As determined by DPPH (27.43 μmol ascorbic acid equivalents (AAE)/g), FRAP (49.79 μmol AAE/g), and H2O2 (230.95 μmol AAE/g) assays, the optimized aqueous extract showed a high antioxidant capacity. Furthermore, it demonstrated considerable anti-inflammatory activity at 17.89%, with the potential to increase to 75.12% under particular extraction conditions. Given the high added-value of the aqueous extracts, the results of this study highlight the potential utility of C. sativa leaves as a source of health-improving antioxidant compounds in the pharmaceutical and food industries.

In Cameroon, local plants are traditionally used as remedies for a variety of ailments. In this regard, several papers report health benefits of Cameroonian spices, which include antioxidant and anti-microbial properties, whereas gastric anti-inflammatory activities have never been previously considered. The present study investigates the antioxidant and anti-inflammatory activities of hydro-alcoholic extracts of eleven Cameroonian spices in gastric epithelial cells (AGS and GES-1 cells). The extracts showed antioxidant properties in a cell-free system and reduced H2O2-induced ROS generation in gastric epithelial cells. After preliminary screening on TNFα-induced NF-κB driven transcription, six extracts from Xylopia parviflora, Xylopia aethiopica, Tetrapleura tetraptera, Dichrostachys glomerata, Aframomum melegueta, and Aframomum citratum were selected for further studies focusing on the anti-inflammatory activity. The extracts reduced the expression of some NF-κB-dependent pro-inflammatory mediators strictly involved in the gastric inflammatory process, such as IL-8, IL-6, and enzymes such as PTGS2 (COX-2), without affecting PTGS1 (COX-1). In conclusion, the selected extracts decreased pro-inflammatory markers by inhibiting the NF-κB signaling in gastric cells, justifying, in part, the traditional use of these spices. Other molecular mechanisms cannot be excluded, and further studies are needed to better clarify their biological activities at the gastric level.

Increasing evidence supports the potential health benefits of herbal extracts displaying antioxidant, anti-inflammatory and antitumour activities. Environment can have a pronounced effect on phenolic content and antioxidant capacity. The objectives of this study were to evaluate the total phenolic contents and antioxidant capacities of five different herbs grown under greenhouse and field conditions and to assess their potential anti-inflammatory effects. High total polyphenolic (TPP) content (measured by the Folin-Ciocalteu reagent method) and high Trolox equivalent antioxidant capacity (TEAC) were observed in all herbs evaluated. Leaves from thyme, sage, spearmint and peppermint grown in the greenhouse showed significantly higher TPP content and TEAC than those grown under field conditions, with a threefold difference being observed in peppermint. Rosemary, spearmint and peppermint extracts showed stronger inhibition of cyclooxygenase COX-2 than of COX-1. The results show that producing herbs under greenhouse conditions can improve their biological activities by increasing TPP contents and antioxidant capacities. The selective inhibition of COX-2 activity by rosemary, spearmint and peppermint suggests that they may be useful as anti-inflammatory agents with fewer side effects than regular non-steroidal drugs.

The content of insoluble bound phenolic acids in pearled barley was determined by an analytical system consisting of alkaline hydrolysis extraction, high-performance liquid chromatographic separation and electrochemical detection. Insoluble bound phenolic acids in five pearled cultivars and fifteen breeding lines of barley comprised ferulic acid (4.3-34.2mg/100 g dry matter), sinapic acid (0.025-0.445 mg/100 g), caffeic acid(0.002-0.016 mg/100 g). Soluble free polyphenols comprised procyanidins(12.2-80.3 mg/100 g), catechin (0.1-28.2 mg/100 g), and total pholyphenolcomprised 152.4-324.0 mg-gallic acid equivalents/100 g. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity for the barley samples ranged from 403 to 1501 μmol-Trolox equivalents/100 g whereas those of oxygen radical absorbance capacity (ORAC) ranged from 1050 to 3816 μmol-Trolox equivalents/100 g. High correlation (0.980, p<0.01) was found between the DPPH and ORAC assays. Total polyphenol contents positively correlated with the DPPH (0.875, p<0.01)and ORAC (0.881, p<0.01)assays. The correlation coefficient between insoluble bound phenolic acids and total polyphenol contents was higher than that between soluble free polyphenols and total poly-phenol contents. Taken together, the insoluble bound phenolic acids appear to greately contributed to the antioxidant activity in pearled barley.

Five cultivars from each of the three types of pseudocereals, i.e. buckwheat, amaranth, and quinoa, were studied for total polyphenol and rutin contents as well as total antioxidant capacity of seeds. A spectrophotometric method was used for the determination of total polyphenol content (using the Folin-Ciocalteau reagent) and total antioxidant capacity (using DPPH). Rutin content in pseudocereal seeds was determined by HPLC. The determined total polyphenol content in seeds of buckwheat, amaranth, and quinoa cultivars was in the intervals of 15 874&amp;ndash;71 359 mg/kg DM, 1381&amp;ndash;2870&amp;nbsp;mg/kg DM, and 459&amp;ndash;1839 mg/kg DM, respectively. Rutin content in buckwheat, amaranth, and quinoa seeds was in the intervals of 8722&amp;ndash;17&amp;nbsp;125 mg/kg DM, 310&amp;ndash;508 mg/kg DM, and 170&amp;ndash;368 mg/kg DM,respectively. The presented results confirmed a statistically significant influence of cultivar on total polyphenol and rutin contents as well as on total antioxidant capacity of pseudocereal seeds.