Effects of time and extraction temperature on phenolic composition and functional properties of red rooibos (Aspalathus linearis)

Bioaccessibility of bioactive compounds from Pereskia aculeata and their cellular antioxidant effect

Ora-pro-nobis (Pereskia aculeata) is a Cactaceae plant with edible leaves and fruits whose extracts are consumed to promote health, albeit bioactive compounds' bioaccessibility was still not assessed. To address this, ora-pro-nobis fruits (FE) and leaf extracts (LE) were subjected to in vitro digestion to better understand how this process impacts the bioactivities of the extracts. The study investigated the composition of the extracts, their cytotoxicity, and their chemical, plasmatic, and cellular antioxidant capacity. The results revealed that total polyphenolics were about 70% bioaccessible in LE and FE, with phenylalanine being the most bioaccessible essential amino acid in leaves (42.7%) and fruits (83.6%). The samples' antioxidant activity (CUPRAC) was reduced by 25%. LE demonstrated antioxidant activity against human plasma oxidation and haemolysis (21.8%), but digestion mitigated these activities. FE diminished haemolysis (47.0%) and presented cytotoxicity (IC50 = 1086 μg/mL) to HUVEC cells, but these properties were lost following digestion. Ultimately, digestion partially degraded the samples' bioactive compounds, diminishing their cellular protection against oxidative stress.

High-throughput synchronous erythrocyte cellular antioxidant activity and protection screening of phenolic-rich extracts: Protocol validation and applications

Oxidative/nitrosative damage takes part in chronic disease development, which generates an urgent need for intervention and better therapies to manage them. The scientific community has demanded easy-to-run, cheap, and reliable methods for cellular antioxidant activity assays. This work standardised and validated an erythrocyte cellular antioxidant activity and membrane protection/injury (HERYCA-P) protocol to study food-derive extracts. The method measures intracellular reactive oxygen species (ROS) generation, lipoperoxidation, and haemolysis induced by 2,2'-azobis(2-amidinopropane) dihydrochloride. Quercetin decreased ROS generation by 50.4% and haemolysis by 2.2%, while ascorbic acid inhibited lipid peroxidation by 40.1%. Total phenolic contents of teas were correlated with decreased ROS generation (r = -0.924), lipoperoxidation (r = -0.951), and haemolysis (r = -0.869). The erythrocyte ROS generation and lipoperoxidation were also associated with CUPRAC (r = -0.925; r = -0.951) and hydroxyl radical scavenging activity (r = -0.936; r = -0.949). The precision rates of antioxidant standards and tea samples were below 15%. HERYCA-P is feasible as a complementary antioxidant assay for food matrices.

Metabolomic profiling of wild rooibos (Aspalathus linearis) ecotypes and their antioxidant-derived phytopharmaceutical potential

INTRODUCTION

Aspalathus linearis (commonly known as rooibos) is endemic to the Cape Floristic Region of South Africa and is a popular herbal drink and skin phytotherapeutic ingredient, with health benefits derived primarily from its unique phenolic content. Several, seemingly habitat-specific ecotypes from the Cederberg (Western Cape) and Northern Cape have morphological, ecological, genetic and biochemical differences.

OBJECTIVES AND METHODS

Despite the commercial popularity of the cultivated variety, the uncultivated ecotypes are largely understudied. To address gaps in knowledge about the biochemical constituency, ultra-performance liquid chromatography-mass spectrometry analysis of fifteen populations was performed, enabling high-throughput metabolomic fingerprinting of 50% (v/v) methanolic extracts. Antioxidant screening of selected populations was performed via three assays and antimicrobial activity on two microbial species was assessed. The metabolomic results were corroborated with total phenolic and flavonoid screening of the extracts.

RESULTS AND DISCUSSION

Site-specific chemical lineages of rooibos ecotypes were confirmed via multivariate data analyses. Important features identified via PLS-DA disclosed higher relative abundances of certain tentative metabolites (e.g., rutin, aspalathin and apiin) present in the Dobbelaarskop, Blomfontein, Welbedacht and Eselbank sites, in comparison to other locations. Several unknown novel metabolites (e.g., m/z 155.0369, 231.0513, 443.1197, 695.2883) are responsible for metabolomic separation of the populations, four of which showed higher amounts of key metabolites and were thus selected for bioactivity analysis. The Welbedacht and Eselbank site 2 populations consistently displayed higher antioxidant activities, with 2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities of 679.894 ± 3.427 µmol Trolox/g dry matter and 635.066 ± 5.140 µmol Trolox/g dry matter, respectively, in correlation with a high number of phenolic and flavonoid compounds. The contribution of the individual metabolites to the pharmacological effectiveness of rooibos remains unknown and as such, further structural elucidation and phytopharmacological testing is thus urgently needed.

Synthesis of iron oxide nanoparticles mediated by Camellia sinensis var. Assamica for Cr(VI) adsorption and detoxification

Environment-benign synthesis of nanoparticles (NPs) are of great importance. Plant-based polyphenols (PPs) are electron donor analytes for the synthesis of metal and metal oxide NPs. This work produced and investigated iron oxide nanoparticles (IONPs) from PPs of tea leaves of Camellia sinensis var. assamica for Cr(VI) removal. The conditions for IONPs synthesis were using RSM CCD and found to be optimum at a time of 48 min, temperature of 26 °C, and iron precursors/leaves extract ratio (v/v) of 0.36. Further, these synthesized IONPs at a dosage of 0.75 g/L, temperature of 25 °C, and pH 2 achieved a maximum of 96% Cr(VI) removal from 40 mg/L of Cr(VI) concentration. The exothermic adsorption process followed the pseudo-second-order model, and Langmuir isotherm estimated a remarkable maximum adsorption capacity (Q_m) of 1272 mg g^-1 of IONPs. The proposed mechanistic for Cr(VI) removal and detoxification involved adsorption and its reduction to Cr(III), followed by Cr(III)/Fe(III) co-precipitation.

Antioxidant, antihyperglycemic, and antihyperlipidemic properties of Chimonanthus salicifolius S. Y. Hu leaves in experimental animals: modulation of thioredoxin and glutathione systems, renal water reabsorption, and gut microbiota

Introduction

Excessive calorie intake and physical inactivity have dramatically increased nutrient overload-associated disease, becoming a global public health issue. Chimonanthus salicifolius S. Y. Hu (CHI) is a homology plant of food and medicine in China and shows several health benefits.

Methods

This work investigated the antioxidant activity, the alleviating effects, and the mechanism of action on diabetes and hyperlipidemia of CHI leaves.

Results and discussion

Results showed that CHI leaves infusion displayed in vitro antioxidant activity measured by ABTS and ferric reducing antioxidant power methods. In wild-type Kunming mice, CHI leaves infusion consumption activated the hepatic antioxidant enzymes, including glutathione reductase, glutathione S-transferase, glutathione peroxidase and thioredoxin reductase as well as thioredoxin reductase 1. In alloxan-induced type 1 diabetic mice, CHI leaves infusion ameliorated diabetic symptoms, including polyuria, polydipsia, polyphagia and hyperglycemia, in a dose-dependent and time-course manners. The mechanism involved CHI leaves up-regulating renal water reabsorption associated protein - urine transporter A1-and promoting the trafficking of urine transporter A1 and aquaporin 2 to the apical plasma membrane. Despite this, in high-fat diet-induced hyperlipidemic golden hamsters, CHI leaves powder did not significantly effect on hyperlipidemia and body weight gain. This might be attributed to CHI leaves powder increasing the calorie intake. Interestingly, we found that CHI leaves extract containing a lower dose of total flavonoid than CHI leaves powder pronouncedly reduced the levels of total cholesterol, triglyceride, and low-density lipoprotein cholesterol in serum in golden hamsters fed a high-fat diet. Furthermore, CHI leaves extract elevated the diversity of gut microbiota and the abundance of Bifidobacterium and Ruminococcaceae_UCG-014. It also decreased the abundance of Lactobacillus at the genus level in golden hamsters fed a high-fat diet. Overall, CHI leaves benefit oxidative stress prevention and metabolic syndrome amelioration in vivo.

Manufacturing and characterization of whey and stevia-based popsicles enriched with concentrated beetroot juice

The beet-root (Beta vulgaris) and whey powder together, can potentially use as a multifunctional ingredient in the manufacturing of the "Popsicles", due to their biochemical composition that can enhance the concentration of bioactive compounds. In the present study, beet-root juice concentrates were prepared at different time/temperature treatments viz 45 °C, 55 °C, and 65 °C for 120, 80 and 45 min. The effect of different time/temperature treatments on physicochemical composition, colour, antioxidant activity (%), bioactive compounds, spectral data and sensory acceptance were evaluated. The physicochemical parameters of popsicles (PTI, PT2, PT3) including protein, total phenols, betalain, radical scavenging activity %, colour and melting values were significantly affected (p ≤ 0.05) by the different time/temperature treatments. The concentration of betalain and protein in all the popsicles ranged from 1134 to 1299 mg/L and 1.92 to 1.54 g/100 g respectively. The reduction of bioactive components viz betacyanins, betaxanthins, betanin, oxalic and syringic acid was also observed in popsicle (PTI) as compared to control. Furthermore, popsicle (PT1) was prepared with beet-root juice concentrated at 45 °C showed maximum sensory acceptance. The physicochemical and organoleptic attributes of processed popsicles encourage the commercial usage of whey powder and concentrated beetroot juice.

A narrative review: The pharmaceutical evolution of phenolic syringaldehyde

To better understand the pharmacological characters of syringaldehyde (SA), which is a key-odorant compound of whisky and brandy, this review article is the first to compile the published literature for molecular docking that were subsequently validated by in vitro and in vivo assays to predict and develop insights into the medicinal properties of SA in terms of anti-oxidation, anti-inflammation, and anti-diabetes. The molecular docking displayed significantly binding affinity for SA towards tumor necrosis factor-α, interleukin-6, and antioxidant enzymes when inflammation from myocardial infarction and spinal cord ischemia. Moreover, SA nicely docked with dipeptidyl peptidase-IV, glucagon-like peptide 1 receptor, peroxisome proliferator-activated receptor, acetylcholine M2 receptor, and acetylcholinesterase in anti-diabetes investigations. These are associated with (1) an increase glucose utilization and insulin sensitivity to an anti-hyperglycemic effect; and (2) to potentiate intestinal contractility to abolish the α-amylase reaction when concurrently reducing retention time and glucose absorption of the intestinal tract to achieve a glucose-lowering effect. In silico screening of multi-targets concomitantly with preclinical tests could provide a potential exploration for new indications for drug discovery and development.

Optimising the Polyphenolic Content and Antioxidant Activity of Green Rooibos (Aspalathus linearis) Using Beta-Cyclodextrin Assisted Extraction

Antioxidant activity associated with green rooibos infusions is attributed to the activity of polyphenols, particularly aspalathin and nothofagin. This study aimed to optimise β-cyclodextrin (β-CD)-assisted extraction of crude green rooibos (CGRE) via total polyphenolic content (TPC) and antioxidant activity assays. Response surface methodology (RSM) permitted optimisation of β-CD concentration (0−15 mM), temperature (40−90 °C) and time (15−60 min). Optimal extraction conditions were: 15 mM β-CD: 40 °C: 60 min with a desirability of 0.985 yielding TPC of 398.25 mg GAE·g−1, metal chelation (MTC) of 93%, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging of 1689.7 µmol TE·g−1, ferric reducing antioxidant power (FRAP) of 2097.53 µmol AAE·g−1 and oxygen radical absorbance capacity (ORAC) of 11,162.82 TE·g−1. Aspalathin, hyperoside and orientin were the major flavonoids, with quercetin, luteolin and chrysoeriol detected in trace quantities. Differences (p < 0.05) between aqueous and β-CD assisted CGRE was only observed for aspalathin reporting the highest content of 172.25 mg·g−1 of dry matter for extracts produced at optimal extraction conditions. Positive, strong correlations between TPC and antioxidant assays were observed and exhibited regression coefficient (R2) between 0.929−0.978 at p < 0.001. These results demonstrated the capacity of β-CD in increasing polyphenol content of green rooibos.

Research on Antioxidant Performance of Diglucosyl gallic Acid and Its Application in Emulsion Cosmetics

The present study investigates the in vitro tyrosinase inhibition activity, antioxidant capacity of diglucosyl gallic acid as well as its clinical efficacy as a cosmetic ingredient. The results show that diglucosyl gallic acid has a stronger ability to inhibit the activity of tyrosinase compared with VC, and its IC50 value is 2.68 mg/mL. Their potential antioxidant activities are further evaluated by the DPPH (α, α-diphenyl-β-picrylhydrazyl) method and the ABTS [2,2´-azinobis-(3-ethylbenzothiazoline-6-sulphonate)] radical cation (ABTS·⁺ ) method, in which the gallic acid demonstrates a better performance than the traditional antioxidant vitamin C (VC), while the diglucosyl gallic acid shows poorer performance. As to the reducing ability, VC has the best performance, much better than gallic acid and diglucosyl gallic acid. Furthermore, through clinical experiments, it is shown the application of the diglucosyl gallic acid as a cosmetic ingredient can considerably improve the brightness of the skin and meanwhile reduce the area of ultraviolet spots, melanin and erythema over time.

Enhancement of the Green Extraction of Bioactive Molecules from Olea europaea Leaves

Olive leaves are a rich source of polyphenols that have beneficial antihypertensive, hypocholesterolemic, cardioprotective, and anti-inflammatory effects. The aim of this study was to compare the efficiency of conventional extraction (CE), microwave-assisted extraction (MWE), and microwave–ultrasound-assisted extraction (MWUE) for the extraction of bioactive molecules from olive leaves using water as a solvent and to define the optimal extraction conditions for all three methods used. CE conditions (temperature, time, magnetic stirrer rotational rate and particle diameter) and MWE extraction and MWUE conditions (microwave power, time, particle diameter, and temperature) were optimized using response surface methodology (RSM) based on the Box–Behnken experimental design. The total polyphenol content and antioxidant activity of all prepared extracts was analyzed and compared. The results showed that MWUE provided the highest amount of total polyphenols (Total Polyphenolic Content (TPC) = 273.779 ± 4.968 mgGAE gd.m.−1) and the highest antioxidant activity, which was about 3.1 times higher than CE. Optimal extraction conditions were determined to be 80 °C, 15 min, 200 μm, and 750 min-1 for CE, 700 W, 7.5 min, 300 μm, and 80 °C for MWE, and 800 W, 5 min, 100 μm, and 60 °C for MWUE. Considering the maximum amount of total polyphenols extracted, the results suggest that MWUE is the most effective green extraction process that extracted the highest amount of polyphenols and could be used by the food industry for commercial exploitation of currently unprofitable plant bioactive sources.

Extraction optimization of bioactive compounds from ora-pro-nobis (Pereskia aculeata Miller) leaves and their in vitro antioxidant and antihemolytic activities

Ora-pro-nobis (Pereskia aculeata Miller) is a non-conventional food plant common in Brazil. The objective of this study was to optimize the extraction of bioactive phenolic compounds from ora-pro-nobis leaves by employing solvent mixtures. Ten extracts were obtained with water, ethanol, acetone, and their binary and ternary mixtures, evaluating the chemical composition, antioxidant activity and bioactivities in vitro. The response surface methodology was applied to model the results and calculate the optimal solvent composition, which is 60% water, 40% ethanol and 0% acetone. The optimized extract is rich in phenolic compounds (64 mg GAE/g) and proteins (823 mg/g) and presents antioxidant activity (in intracellular media as well) and inhibits lipid peroxidation (32%) along with hypotonic hemolysis (H₅₀ = 0.339%), it does not present toxicity in vitro against cancer and normal cells. This is the first report of chicoric, caffeoyl-hexaric and coumaroyl-hexaric acids and some glycosylate derivatives of flavonols in ora-pro-nobis leaves.

The Effect of Rooibos (Aspalathus linearis), Honeybush (Cyclopia intermedia) and Sutherlandia (Lessertia frutescens) on Testicular Insulin Signalling in Streptozotocin-Induced Diabetes in Wistar Rats

BACKGROUND

Testicular insulin signalling is altered in diabetic (DM) males. While unravelling the mechanism through which DM exert these detrimental effects, studies have shown the importance of insulin regulation in glucose homeostasis, and how a lack in insulin secretion indirectly led to reduced male fertility. The current study aimed to investigate the role of rooibos, honeybush and Sutherlandia on insulin signalling in the testicular tissue of type I diabetic rats.

METHODS

Animals (n=60) were randomly divided into six groups. The groups include a control group, a vehicle group, and diabetes was induced in the remainder of animals via a single intraperitoneal injection of STZ at 45mg/kg. The remaining four groups included a diabetic control (DC), diabetic + rooibos (DRF), diabetic + honeybush (DHB) and diabetic + Sutherlandia group (DSL). Animals were sacrificed after seven weeks of treatment, and blood and testes were collected.

RESULTS

All diabetic groups (DC, DRF, DHB, DSL) presented with a significant increase in blood glucose levels after diabetes induction compared to the control and vehicle (p<0.001). The DC animals presented with decreased testicular protein expression of IRS-1, PkB/Akt and GLUT4 compared to controls. DRF and DHB animals displayed an acute upregulation in IRS-1, while the DSL group showed improvement in IRS-2 compared to DC. Although, DRF animals presented with a decrease in PkB/Akt, DHB and DSL animals displayed upregulation (22.3%, 48%) compared to controls, respectively.

CONCLUSION

The results taken together, it can be suggested that these infusions may enhance insulin signalling through diverse pathways.

Twenty-five years of total antioxidant capacity measurement of foods and biological fluids: merits and limitations

This review summarises 25 years of investigations on antioxidants research in foods and biological fluids and critically analyses the merits and limitations of using the total antioxidant capacity (TAC) measurement in the metabolomic era. An enormous bulk of knowledge was produced regarding the antioxidant capacity of foods and large TAC databases were developed. A direct link between a food TAC value and any health benefit is erroneous and has led to several cases of consumer deception. However, the striking epidemiological evidence associating a high dietary TAC with some disease prevention and the availability of well-constructed TAC databases deserve attention and must be taken into account to establish the usefulness of measuring TAC in both foods and biological samples. The in vivo TAC measurement, usually performed in plasma, is influenced by many external factors, such as dietary habits, as well as environmental and behavioural factors, which are integrated towards homeostatic control by fine physiological mechanisms with high inter-individual variability. Therefore, plasma TAC cannot be considered as a unique biomarker of individual antioxidant status. However, the combined evaluation of plasma TAC with known markers of disease, individual metabolism, inflammation and genetics, as well as with markers of gut microbiota composition and activity, may lead to the identification of populations that are more responsive to food/diet TAC. In this framework, the appropriate use of TAC measurement both in food and in vivo can still provide support for the interpretation of complex phenomena and be a tool for sample screening when making a quick decision toward in-depth research investigations. © 2018 Society of Chemical Industry.

Apigenin, flavonoid component isolated from Gentiana veitchiorum flower suppresses the oxidative stress through LDLR-LCAT signaling pathway

Flower of Gentiana veitchiorum has traditionally been used as an herbal medicine in Tibet for treatment of variola, respiratory infection, and pneumonia. However, the effective components contained in flower are not identified yet, and the underlying mechanisms for anti-inflammatory, antibacterial, and antioxidative activities remain to be elucidated. Here, we first extracted the flavonoid mixture from G. veitchiorum flower. The mixture was then further isolated and the within compounds was identified through the high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The results showed that apigenin (4',5,7-trihydroxyflavone) was the most abundant flavonoid in G. veitchiorum flower. We next examined the antioxidative activity of the extracted apigenin using the ferric reducing/antioxidant power (FRAP), the 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) assays and found that a positive correlation between apigenin concentration and reactive oxygen species (ROS) scavenging rate. The biochemical assays further revealed that the levels of total cholesterol (TC), triglyceride (TG), and malondialdehyde (MDA) were reduced, while the activity of superoxide dismutase (SOD) was increased after apigenin treatment in hyperlipidemic rats. Moreover, we performed histopathological investigations and found that the lipidic deposition patterns were recovered and the amount of lipid vacuoles was significantly reduced in apigenin-treated hyperlipidemic rat liver. Western blotting assay showed that the expression of low-density lipoprotein receptor (LDLR) and lecithin-cholesterol acyltransferase (LCAT) were up-regulated in the apigenin-treated samples. Overall, our results demonstrated that the apigenin isolated from G. veitchiorum flower exhibited radical scavenging activities, and reversed the high fat diet-induced oxidative damage in rats. Its antioxidative activities are probably achieved via LDLR-LCAT signaling pathway.

Optimization of ultrasonic-assisted extraction conditions for bioactive components from coffee leaves using the Taguchi design and response surface methodology

Coffee leaves contain various bioactive compounds that are beneficial for human health. However, there are very limited researches related to the extraction of the bioactive phytochemicals from coffee leaves. In the present study, the extraction conditions for bioactive components from coffee leaves were optimized using Taguchi design and response surface methodology (RSM). Taguchi design was used to screen significant factors that affected the yield of phytochemicals including trigonelline, caffeine, chlorogenic acids, mangiferin, and rutin, total phenolic content (TPC) and antioxidant activity. Sequentially, a Box-Behnken design (BBD) was used to optimize the extraction conditions. Three factors including Liquid-to-solid (L:S) ratio, ethanol concentration, and extraction temperature that significantly affected most of the phytochemical yields and antioxidant activity were selected from the six variables using Taguchi design. The optimal extraction conditions obtained from RSM were 30.3:1 L:S ratio, 54.5% ethanol, and 80 °C when simultaneously considered four responses, including TPC, the yields of mangiferin and 5-CQA and DPPH scavenging capacity. Under the optimal conditions, the experimental results for the above four responses were 62.1 mg gallic acid/g, 4.1 mg/g, 11.4 mg/g, and 356.9 µmol Trolox/g, respectively, which were close to the predicted values. About 97% of phytochemicals can be extracted in the first two times of extraction. In conclusion, the combination of Taguchi design and response surface methodology can be successfully used to screen and optimize the significant factors that affected the bioactive components extracted from coffee leaves. PRACTICAL APPLICATION: Coffee leaves, the byproducts of coffee plants, are considered no- or low-value although it has a long history for using them as tea-like beverage and ethnomedicine by locals in the coffee plant growing countries. Bioactive components extracted from coffee leaves can be used as ingredients in functional beverages, functional food, and natural health products. These applications will add values to coffee leaves as well as increase the incomes of coffee farmers and workers.

Comparison of conventional extraction technique with ultrasound assisted extraction on recovery of phenolic compounds from lemon scented tea tree (Leptospermum petersonii) leaves

Leptospermum petersonii is a native Australian medicinal and aromatic plant. This study was designed to evaluate the influence of solvents and ultrasound-assisted extraction (UAE) parameters including time, temperature, and sonication power on the yield of phenolic compounds and antioxidant capacity from lemon scented tea tree leaves. Extraction efficiency of the optimal UAE conditions were compared with that of shaking water bath technique. The results show that extraction solvents significantly affect extraction yield of phenolic compounds and antioxidant properties, and 50% acetone in water was found to be the most suitable solvent. The UAE optimal conditions were 60 min, 50 °C and sonication power of 200 W. Under these optimal conditions the yields of total phenolics, flavonoids, proanthocyanidins were 98.91 ± 1.20 (mg GAE/g DW), 76.12 ± 0.79 (mg CE/g DW), 117.71 ± 2.18 (mg CE/g DW), respectively. Antioxidant properties from four assays including FRAP, CUPRAC, ABTS and DPPH were 581.29 ± 14.23, 5534.87 ± 19.56, 1636.18 ± 4.11, and 889.29 ± 20.68 (mM TE/g DW) respectively. The UAE extraction technique was found to be more efficient in extraction of total phenolics and antioxidant capacity in comparison with conventional shaking water bath extraction. This study also observed a strong correlation between phenolic compounds and antioxidant capacities. All three phenolic compound groups (TPC, TFC, and Pro.A) were contributed to both free radical scavenging and ion reducing properties in the lemon scented tea tree leaves extract. However, the order of the phenolic groups was TPC > Pro.A > TFC for antioxidant properties.

A new analytical concept based on chemistry and toxicology for herbal extracts analysis: From phenolic composition to bioactivity

Studies regarding the bioactivity of teas are mainly based on the phenolic composition and in vitro antioxidant activity of the herbal species used in their preparation. The aim of this study was to compare the in vitro and ex vivo antioxidant activity, cytotoxic/antiproliferative activity against cancer cells, the inhibitory activity of α-amylase, α-glucosidase and angiotensin I-converting enzymes, as well as the inhibition of DNA-induced fission of the peroxyl radical, in relation to aqueous extracts of Camellia sinensis var. sinensis (CS), Ilex paraguariensis (IP), Aspalathus linearis (AL) and an optimised extract (OT) containing the three herb species. A bivariate and multivariate statistical approach was employed to associate functional activities with individual phenolic composition. The CS and OT extracts showed the highest levels of hesperidin, quercetin-3-rutinoside, (-)-epigallocatechin-3-gallate and isoquercitrin. The CS and OT extracts showed the highest antioxidant activity, greater ability to inhibit α-amylase and proliferation of HCT8 cells, and greater ability to reduce Folin-Ciocalteu reagent. The AL extract, which is the major source of quercetin-3-rutinoside, hesperidin and isoquercitrin, showed the highest ability to inhibit α-glucosidase, the inhibition of LDL oxidation and protection of human erythrocytes. The IP extract showed the highest inhibition of lipoperoxidation in brain homogenate of Wistar rats, antihypertensive activity, and A549 cell proliferation; chlorogenic acid was its major phenolic compound. In general, the in vitro functionality of each extract was dependent on its chemical composition and the OT extract presented the most varied phenolic composition, and biological activity similar to the CS sample. In conclusion, the mixture of CS, AL, and IP represents a chemical and functional-based strategy to develop functional teas.

Impact of Cold versus Hot Brewing on the Phenolic Profile and Antioxidant Capacity of Rooibos (Aspalathus linearis) Herbal Tea

Consumption of rooibos (Aspalathus linearis) as herbal tea is growing in popularity worldwide and its health-promoting attributes are mainly ascribed to its phenolic composition, which may be affected by the brewing conditions used. An aspect so far overlooked is the impact of cold brewing vs regular brewing and microwave boiling on the poly(phenolic) profile and in vitro antioxidant capacity of infusions prepared from red ('fermented', oxidized) and green ('unfermented', unoxidized) rooibos, the purpose of the present study. By using an untargeted metabolomics-based approach (UHPLC-QTOF mass spectrometry), 187 phenolic compounds were putatively annotated in both rooibos types, with flavonoids, tyrosols, and phenolic acids the most represented type of phenolic classes. Multivariate statistics (OPLS-DA) highlighted the phenolic classes most affected by the brewing conditions. Similar antioxidant capacities (ORAC and ABTS assays) were observed between cold- and regular-brewed green rooibos and boiled-brewed red rooibos. However, boiling green and red rooibos delivered infusions with the highest antioxidant capacities and total polyphenol content. The polyphenol content strongly correlated with the in vitro antioxidant capacities, especially for flavonoids and phenolic acids. These results contribute to a better understanding of the impact of the preparation method on the potential health benefits of rooibos tea.

Optimization of Caesalpinia sappan L. heartwood extraction procedure to obtain the highest content of brazilin and greatest antibacterial activity

OBJECTIVE

The objective of the work was to optimize the extraction conditions of Caesalpinia sappan L. heartwood in order to maximize the brazilin content and antibacterial activity of the extract.

METHODS

Two independent factors were studied: extraction temperature (45-95 °C) and extraction time (30-60 min). In addition, five dependent factors were monitored, including extraction yield, brazilin content, and clear zones against Staphylococcus aureus TISTR 1466, Staphylococcus epidermidis TISTR 518 and Propionibacterium acnes DMST 14961. The brazilin content was quantified by high-performance liquid chromatography and antibacterial activity was determined by disk diffusion assay.

RESULTS

The high temperature provided high total extract yield as well as brazilin content, while extraction time had little effect on yield or brazilin content. Extraction time had a positive effect, while extraction temperature had little effect on clear zone against S. aureus. The largest clear zone against S. epidermidis was achieved at low extraction temperature and long extraction time. Conversely, short extraction time and high extraction temperature provided the largest clear zone against P. acnes. The optimal conditions providing the highest brazilin content was an extraction temperature and extraction time of 95 °C and 30 min, respectively. The same optimal conditions also provided the simultaneous greatest antibacterial activity against the three bacteria. Modeled optimal conditions were validated be conducting extraction using these values. Yield and antibacterial activity of the resulting extract demonstrated that the model had a low percentage error.

CONCLUSION

The optimal condition will be used as a standard condition for extraction of C. sappan heartwood to maximize brazilin content and antibacterial activity.

Chemical, sensory, and functional properties of whey-based popsicles manufactured with watermelon juice concentrated at different temperatures

The effects of the concentration of watermelon juice at different temperatures (45, 55, or 65 °C) on the physicochemical and sensory characteristics, antioxidant capacity, and volatile organic compounds (VOCs) of whey-based popsicles were investigated. Total phenolic content, lycopene, citrulline, VOCs, melting rate, instrumental colour, antioxidant capacity, and the sensory characteristics (hedonic test and free listing) were determined. The temperature led to a significant decrease in bioactive compounds (total phenolics, lycopene, and citrulline). The popsicle manufactured with reconstituted watermelon juice concentrated to 60 °Brix at 65 °C presented higher antioxidant capacity and was characterized by the presence of alcohols, aldehydes and ketones and presented a similar acceptance to the untreated popsicle (except for flavour). It is possible to combine whey and concentrated watermelon juice for the manufacture of bioactive-rich popsicles, using the concentration temperature of 65 °C as a suitable processing condition for potential industrial applications.

Simultaneous optimization of the ultrasound-assisted extraction for phenolic compounds content and antioxidant activity of Lycium ruthenicum Murr. fruit using response surface methodology

Lycium ruthenicum Murr. (LR) is a functional food that plays an important role in anti-oxidation due to its high level of phenolic compounds. This study aims to optimize ultrasound-assisted extraction (UAE) of phenolic compounds and antioxidant activities of obtained extracts from LR using response surface methodology (RSM). A four-factor-three-level Box-Behnken design (BBD) was employed to discuss the following extracting parameters: extraction time (X₁), ultrasonic power (X₂), solvent to sample ratio (X₃) and solvent concentration (X₄). The analysis of variance (ANOVA) results revealed that the solvent to sample ratio had a significant influence on all responses, while the extraction time had no statistically significant effect on phenolic compounds. The optimum values of the combination of phenolic compounds and antioxidant activities were obtained for X₁=30min, X₂=100W, X₃=40mL/g, and X₄=33% (v/v). Five phenolic acids, including chlorogenic acid, caffeic acid, syringic acid, p-coumaric acid and ferulic acid, were analyzed by HPLC. Our results indicated that optimization extraction is vital for the quantification of phenolic compounds and antioxidant activity in LR, which may be contributed to large-scale industrial applications and future pharmacological activities research.