Natural Bioactive Compounds Research Articles

Foods and beverages made from Mexican Purple Corn: a means to increase anthocyanins’ intake

Background: Anthocyanins (AAs) are natural pigments and bioactive compounds that are of broad interest due to their potential beneficial effects on health. In the market, while some foods, such as berries, provide important amino acid (AA) intakes, there is a growing trend to explore new sources. In Mexico, there is the Mexican Purple Corn, a variant capable to produce AAs in all the organs of the corn ear. We overlook that the preparation of foods and beverages from these raw materials may represent the development of potential functional foods and a means to increase the dietary intake of AAs. Methods: We used spectrophotometry to quantify the total anthocyanins content (TAC) of three foods made from purple kernels, and six beverages prepared from corn husks+corncobs or corn silks. Foods consisted of elote (Mexican street corn or corn on a cob), a snack, and tortillas, while beverages involved what we named functional beverages, infusions, and hot teas. We compared their TAC values and estimated the AAs intake. Results: Foods and beverages exhibited total antioxidant capacities (TACs) ranging from 3.0 mg to 119.5 mg per 100 g of biomass (p ≤ 0.05). Notably, most beverages demonstrated higher TACs than foods. The corn husks+corncobs infusion recorded the highest TAC, succeeded by functional beverages derived from amino acid (AA) extracts of corn husks+corncobs (67.04 and 93.12 mg of TAC per 100 g of biomass, p ≤ 0.05). Among hot teas and infusions, maceration in the latter resulted in a higher AA extraction. For foods, TACs varied from 4.3 to 38.4 mg of TAC per 100 g of biomass, and, similar to beverages, the preparation process influenced TAC. The roasted snack exhibited a higher AA content. Conclusion: Mexican Purple Corn shows promise as a source for foods and beverages rich in amino acids (AAs). This crop represents an option to increase the daily intake of this flavonoid, and to acquire its potential bioactive effects. On a regular day, we can obtain 95 mg of TA from 300 g of purple corn-based foods, and 750 mL of different beverages made from corn husks, corncobs, and corn silks. Keywords: Mexican Purple Corn, anthocyanins, corn husks, corncobs, corn silks, dietary source of anthocyanins.

Evaluation of the Effectiveness of Staphylococcus Phages in a Skincare Serum against Staphylococcus spp.

The emergence of multidrug-resistant (MDR) Staphylococcus spp. has resulted in the reduced use of antibiotics in many skincare cosmetic products. Alternative treatments using natural bioactive compounds and chemical agents can be replaced. However, these compounds have induced negative side effects among users and are not environmentally friendly. Phage therapy is an alternative to antibiotics for the treatment of specific pathogenic bacteria including Staphylococcus spp., without harmful effects on human skin cells and microflora. Phages can be potentially used in cosmetic products. The direct application of phage-based cosmetic products on skin can reduce the chance of skin infection caused by pathogenic Staphylococcus spp. In the present work, we isolated 17 Staphylococcus phages from sewage and soil samples. Phage A1 showed the highest lytic ability at 50% (B1 profile), covering 13 tested Staphylococcus isolates including Staphylococcus aureus (SA), methicillin-resistant S. aureus (MRSA), S. capitis (SC), and S. epidermidis (SE). Phage A1 reduced the representative S. aureus ATCC 25923 and S. capitis SC1 by 2.0 ± 0.1 and 4.1 ± 0.3 log units at a multiplicity of infection (MOI) of 104 and by 4.2 ± 0.2 and 4.4 ± 0.5 log units at a MOI of 105 after 6 h of post-phage treatment. The transmission electron microscope revealed that phage A1 was classified in the order Caudovirales of the family Myoviridae based on its appearance. Phage A1 showed optimal survival in the presence of a 0.125% (v/v) solidant DMH suspension after 3 h of post-treatment. Under a phage skincare serum formulation, the titers of phage A1 were reduced by 0.46 and 0.85 log units after storage at 4 and 25 °C, whereas a reduction of 2.96 log units was also observed after storage at 37° for 90 days. This study provides strong evidence for the effectiveness of phage application in cosmetic skincare serum for the treatment of skin diseases caused by MDR and pathogenic Staphylococcus spp. The concept of this study could be advantageous for cosmetic and/or cosmeceutical industries searching for new bioactive ingredients for cosmetic/cosmeceutical products.

The Impact of Different Withering Process Conditions on the Bioactivity and Quality of Black Tea from Azorean Camellia sinensis

The objective of this study was to investigate the variability of natural bioactive compounds, such as catechin, theaflavin, total phenolic content (TPC), and total flavonoid content (TFC), of Azorean black tea (Camellia sinensis L., O. Kuntze) as well as its antioxidant activities according to different withering times. The TPC, TFC, free radical scavenging activity (FRSA), ferric reducing antioxidant power (FRAP), and ferrous-ion-chelating (FIC) activities were determined by colorimetric methods, and catechin and theaflavin contents were analyzed by high-pressure liquid chromatography (HPLC). The FRSA shows similar results for the withering range of 6 to 16 h (hours). For FRAP, the best results were observed at 16 h, and for FIC, the highest value was at 20 h. The TPC and TFC showed the highest value at 9 h and the lowest at 20 h. For the total theaflavins, the highest results were obtained after 12 h of withering, and the lowest values were obtained at 16 and 20 h. According to the different withering times, the highest value of total catechin levels was at 12 h, while the lowest value was observed at 20 h. Regarding caffeine content, all samples presented similar results, with the exception of the 12 h time point. In conclusion, the best withering times were observed in the range of 9 to 16 h, showing decreased values at 20 h, with the exception of FIC.

Allicin extracted from Allium sativum shows potent anti-cancer and antioxidant properties in zebrafish

Garlic (Allium sativum) is an important flavouring component in Indian cuisine. Allicin, a sulphur containing compound, is the most abundant component of garlic and has been widely studied for its antimicrobial and antioxidant properties. It is also known to play a role in the regulation of blood pressure and cholesterol levels. Despite the known health benefits associated with allicin, systematic studies on its anti-cancer properties using animal models are very limited. This study aimed to develop a simple method for the extraction of allicin from fresh garlic, study the stability of the extracted compound at various temperatures, and evaluate the antioxidant, anti-proliferative, pro-apoptotic and anti-angiogenic properties in zebrafish. A five-month stability study indicated that allicin remains significantly stable at temperatures 4 °C and below but shows extensive degradation if stored at room temperature. The in vivo studies in zebrafish using a combination of mutants and transgenic lines demonstrated the antioxidant, anti-proliferative, apoptotic and anti-angiogenic properties of allicin. The study highlights the importance of natural bioactive compounds as potential anti-cancer agents that can be studied further.

Bioactivity of Fractions and Pure Compounds from Jatropha cordata (Ortega) Müll. Arg. Bark Extracts.

Medicines for chronic inflammation can cause gastric ulcers and hepatic and renal issues. An alternative treatment for chronic inflammation is that of natural bioactive compounds, which present low side effects. Extracts of Jatropha cordata (Ortega) Müll. Arg. have been evaluated for their cytotoxicity and anti-inflammatory activity; however, testing pure compounds would be of greater interest. Campesteryl palmitate, n-heptyl ferulate, palmitic acid, and a mixture of sterols, i.e., brassicasterol, campesterol, β-sitosterol, and stigmasterol, were obtained from an ethyl acetate extract from J. cordata (Ortega) Müll. Arg. bark using column chromatography. The toxicity and in vitro anti-inflammatory activities were evaluated using RAW 264.7 murine macrophage cells. None of the products assessed exhibited toxicity. The sterol mixture exhibited greater anti-inflammatory activity than the positive control, and nitric oxide (NO) inhibition percentages were 37.97% and 41.68% at 22.5 μg/mL and 30 μg/mL, respectively. In addition, n-heptyl ferulate decreased NO by 30.61% at 30 μg/mL, while campesteryl palmitate did not show anti-inflammatory activity greater than the positive control. The mixture and n-heptyl ferulate showed NO inhibition; hence, we may conclude that these compounds have anti-inflammatory potential. Additionally, further research and clinical trials are needed to fully explore the therapeutic potential of these bioactive compounds and their efficacy in treating chronic inflammation.

Cyanidin-3-O-glucoside from blueberry anthocyanin extracts protects ARPE-19 cells against high glucose damage via REDD1/GSK3β pathway

The retinal pigment epithelium (RPE) serves dual roles: it acts as a selective barrier and also as a regulator for the photoreceptor layer situated above it. The RPE is considered a crucial target for halting the development and progression of diabetic retinopathy (DR). This study focuses on understanding the protective role of blueberry anthocyanin extracts (BAEs), particularly its anti-oxidant constituent, cyanidin-3-O-glucoside (C3G), against damage to RPE cells induced by high glucose (HG) levels. The findings revealed that the BAEs mitigated damage to HG-induced ARPE-19 cells by decreasing the intracellular reactive oxygen species (ROS) levels, which improved cell morphology and cell viability (p < 0.01). Importantly, these cytoprotective effects were linked to the C3G rich in BAEs. The underlying mechanism may involve C3G interrupting the ROS generation feedback loop by downregulating REDD1 expression, which in turn enhanced the retinal Nrf2 antioxidant response to HG through the promotion of the GSK3β phosphorylation at Ser-9. Moreover, C3G suppressed VEGFA expression by inhibiting REDD1 levels in HG-induced ARPE-19 cells, subsequently preventing an increase in vascular permeability. In conclusion, this study suggested that the C3G relieved HG-induced oxidative stress damage in ARPE-19 cells via REDD1/GSK3β pathway and inhibited an increase in vascular permeability by downregulating VEGFA expression. These insights could shed light on how this natural bioactive compound can help manage HG-associated eye disorders like DR.

Niosomes gel of apigenin to improve the topical delivery: development, optimization, ex vivo permeation, antioxidant study, and in vivo evaluation

Niosomes (NS) are the promising and novel carrier of the drug for effective transdermal delivery. Apigenin (AN) is a natural bioactive compound and has various pharmacological activities. AN is poorly water soluble which directly affects therapeutic efficacy. The aim of this research work was to develop the AN-NS gel to improve transdermal delivery. The thin-film hydration method was used for the development of AN-NS. The optimized AN-NS (AN-NS2) has a vesicle size of 272.56 ± 12.49 nm, PDI is 0.249, zeta potential is −38.7 mV, and entrapment efficiency of 86.19 ± 1.51%. The FTIR spectra of the AN-NS2 depicted that AN encapsulated in the NS matrix. AN-NS2 formulation was successfully incorporated into chitosan gel and evaluated. The optimized AN-NS2 gel (AN-NS2G4) has 2110 ± 14cps of viscosity, 10.40 ± 0.21g.cm/sec of spreadability, and 99.65 ± 0.53% of drug content. AN-NS2G4 displayed significantly (p < 0.05) higher AN released (67.64 ± 3.03%) than pure AN-gel (37.31 ± 2.87%). AN-NS2G4 showed the Korsmeyer Peppas release model. AN-NS2G4 displayed significantly (p < 0.05) higher antioxidant activity (90.72%) than pure AN (64.53%) at 300 µg/ml. AN-NS2G4 displayed significantly (p < 0.05) higher % inhibition of swelling than pane AN-gel in carrageenin-induced paw oedema in rats. The finding concluded that niosomes-laden gel is a good carrier of drugs to improve transdermal delivery and therapeutic efficacy.

Prospects of earthworm coelomic fluid as a potential therapeutic agent to treat cancer.

Cancer is a major public health concern because it is one of the main causes of morbidity and mortality worldwide. As a result, numerous studies have reported the development of new therapeutic compounds with the aim of selectively treating cancer while having little negative influence on healthy cells. In this context, earthworm coelomic fluid has been acknowledged as a rich source of several bioactive substances that may exhibit promising anticancer activity. Therefore, the objective of the present review is to evaluate the findings of the reported studies exploring the antitumor effects of coelomic fluid in the context of its possible utilization as a natural therapeutic agent to cure different types of cancer. The possible mechanisms underlying the coelomic fluid's anticancerous potential as well as the possibility for future development of cutting-edge therapeutic agents utilizing coelomic fluid-derived natural bioactive compounds to treat cancer disorders have been discussed along with future challenges. In addition, the feasibility of encapsulation of bioactive compounds derived from coelomic fluid with nanomaterials that could be further explored to attain more effective anticancer competence is discussed.

Isolation and Characterization of Chemical Compounds from Terminalia Chebula for Anti-Diabetic Evaluation Through In-Silico Approach

Diabetes is a chronic metabolic disorder affecting millions of people and needs to be addressed. Alternativestrategies are required for better diabetes management, as evidenced by the high costs of modern medicines. The field of herbalmedicine research has been gaining significant importance in the last few decades, and the demand to use natural products in thetreatment of diabetes is increasing across the globe. Traditional plant medicines are used worldwide for a range of diabeticcomplications. Terminalia chebula is one of the widely used traditional medicine by diabetic patients. In this present work,Terminalia chebula fruits were used for the potential of anti-diabetic activity. The phytochemical investigation revealed that itsfruit contains high amounts of tannins, alkaloids, flavonoids, terpenoids, and glycosides. The percolation method was followed byusing T. chebula fruit for the extraction, further fractionating with different solvents, n-Hexane, Ethyl acetate, n- Butanol, andwater. When ethyl acetate extract of T. chebula was tested, it was found to have significant effects on blood glucose levels. Itsuggests that it can be used as an antidiabetic agent. Gallic acid and quercetin were compounds identified by NMR, MS, andUPLC analysis. Molecular docking studies of designed compounds were carried out through Auto Dock Vina [1.1.2] toinvestigate the interaction with PPAR-γ associated with diabetes, and pkCSM software was used for ADMET analysis. Thus, theresult of the study proved that the ethyl acetate extract of T. chebula had good potential as an antidiabetic, and this plant can beused to discover natural bioactive compounds that may serve for the advances of novel pharmaceutical development. Moreover,the compounds found in the extract could be used to develop new pharmaceuticals for diabetes treatment.

A Study on an Active Functional Group and Antimicrobial Properties From Rhizophora apiculata Extracts Used in Traditional Malay as Medicine

A mangrove plant known as Rhizophora apiculata is employed by Malay for treating skin diseases, diarrhea, vomiting, and nausea, as an antiseptic, for tanning, and also as fuelwood and fodder. Its large-scale use can be attributed to its high-quality timber, availability as well and the presence of a chemical named tannin that is employed for reinforcing fishing lines, nets, and ropes. The tannin content of R. apiculata's roots, bark, and leaves is regarded to be a natural inhibitor of fungal infections. This study is focused on determining the different kinds of functional groups, as well as individual phenolic compounds present in R. apiculata for identifying new bioactive compounds via decoding of the traditional values of Malay remedies. There is a high demand for such natural bioactive compounds, particularly in the healthcare and pharmaceutical markets. Alkaline fractional extracts were employed to design an analytical extraction method for R. apiculata. As per the HPLC results, there were three phenolic acids detected namely Caffeic acid, 4-Hydroxybenzoic acid, and Vanillic acid. Meanwhile, ten volatile compounds were identified by the GCTOF-MS. With regards to antibacterial activity, S. aureus, S. epidermidis, and E. coli were inhibited by R. apiculata leaf extract, while C. albicans and Fusarium sp. were inhibited by their antifungal activity.

Synthesis of 10-Membered Azecines through Pd-Catalyzed Formal [6+4] Cycloaddition and Their Transannular Reaction to Polycyclic Compounds.

Azecine fragments are frequently presented in natural products and bioactive compounds. However, minor efforts have been devoted to these 10-membered N-heterocycles, and their synthesis is still challenging. Reported herein is the first catalytic formal [6+4] cycloaddition for the synthesis of 10-membered azecines. Under palladium catalysis, the reaction of δ-vinylvalerolactones and benzofuran-derived azadienes proceeds smoothly to afford benzofuran-fused azecines with high diastereoselectivity in moderate to good yields. A unique transannular reaction of these 10-membered azecines for the construction of polycyclic compounds is also demonstrated.

Natural Polymeric Hydrogels Encapsulating Small Molecules for Diabetic Wound Healing.

Diabetes is a condition correlated with a high number of diagnosed chronic wounds as a result of a complex pathophysiological mechanism. Diabetic chronic wounds are characterized by disorganized and longer stages, compared to normal wound healing. Natural polymer hydrogels can act as good wound dressings due to their versatile physicochemical properties, represented mainly by high water content and good biocompatibility. Natural bioactive hydrogels are polymers loaded with bioactive compounds providing antibacterial and antioxidant properties, modulation of inflammation and adherence to wounded tissue, compared to traditional dressings, which enables promising future applications for diabetic wound healing. Natural bioactive compounds, such as polyphenols, polysaccharides and proteins have great advantages in promoting chronic wound healing in diabetes due to their antioxidant, anti-inflammatory, antimicrobial, anti-allergic and wound healing properties. The present paper aims to review the wound healing mechanisms underlining the main issues of chronic wounds and those specifically occurring in diabetes. Also, the review highlights the recent state of the art related to the effect of hydrogels enriched with natural bioactive compounds developed as biocompatible functional materials for improving diabetic-related chronic wound healing and providing novel therapeutic strategies that could prevent limb amputation and increase the quality of life in diabetic patients.

Methyl cellulose/okra mucilage composite films, functionalized with Hypericum perforatum oil and gentamicin, as a potential wound dressing

There is a growing demand for the development of functional wound dressings enriched with bioactive natural compounds to improve the quality of life of the population by accelerating the healing process of chronic wounds. In this regard, a functional composite film of okra mucilage (OM) and methylcellulose (MC) incorporated with Hypericum perforatum oil (Hp) and gentamicin (G) was prepared and characterized as a wound dressing. Increasing Hp resulted in improved film properties with a more porous structure, higher WVTR, and lower surface hydrophobicity. Furthermore, incorporating Hp into OM:MC films led to increased elongation at the break while reducing the tensile strength of the films. The highest values of total antioxidant capacity (1.09–1.16 mM trolox equivalent) and total phenolic content (13.76–16.94 μg GA equivalent mL−1) were measured in the composite films containing the highest Hp concentration (1.5 %). In addition, OM:MC/HpG composite films exhibited significant antibacterial activity against both E. coli and S. aureus and prevented the transmission of these bacteria through the films. Hp incorporation reduced the cytotoxic effects of OM:MC films on BJ cells and increased the wound closure rate in vitro. In conclusion, the developed OM:MC/HpG composite film can be a promising candidate as a novel wound dressing with its superior properties.

Common Beans as a Source of Amino Acids and Cofactors for Collagen Biosynthesis.

Common beans (Phaseolus vulgaris L.) are widely consumed in diets all over the world and have a significant impact on human health. Proteins, vitamins, minerals, phytochemicals, and other micro- and macronutrients are abundant in these legumes. On the other hand, collagens, the most important constituent of extracellular matrices, account for approximately 25-30 percent of the overall total protein composition within the human body. Hence, the presence of amino acids and other dietary components, including glycine, proline, and lysine, which are constituents of the primary structure of the protein, is required for collagen formation. In this particular context, protein quality is associated with the availability of macronutrients such as the essential amino acid lysine, which can be acquired from meals containing beans. Lysine plays a critical role in the process of post-translational modifications facilitated with enzymes lysyl hydroxylase and lysyl oxidase, which are directly involved in the synthesis and maturation of collagens. Furthermore, collagen biogenesis is influenced by the cellular redox state, which includes important minerals and bioactive chemicals such as iron, copper, and certain quinone cofactors. This study provides a novel perspective on the significant macro- and micronutrients present in Phaseolus vulgaris L., as well as explores the potential application of amino acids and cofactors derived from this legume in the production of collagens and bioavailability. The utilization of macro- and micronutrients obtained from Phaseolus vulgaris L. as a protein source, minerals, and natural bioactive compounds could optimize the capacity to promote the development and durability of collagen macromolecules within the human body.

Enhancing the Antifungal Efficacy of Fluconazole with a Diterpene: Abietic Acid as a Promising Adjuvant to Combat Antifungal Resistance in Candida spp.

The increasing antifungal resistance rates against conventional drugs reveal the urgent need to search for new therapeutic alternatives. In this context, natural bioactive compounds have a critical role in antifungal drug development. Since evidence demonstrates that abietic acid, a diterpene found in Pinus species, has significant antimicrobial properties, this study aimed to evaluate the antifungal activity of abietic acid against Candida spp and its ability to potentiate the activity of fluconazole. Abietic acid was tested both individually and in combination with fluconazole against Candida albicans (CA INCQS 40006), Candida krusei (CK INCQS 40095), and Candida tropicalis (CT INCQS 40042). The microdilution method was used to determine the IC50 and the cell viability curve. Minimum Fungicidal Concentration (MFC) was determined by subculture in a solid medium. The plasma membrane permeability was measured using a fluorescent SYTOX Green probe. While the IC50 of the drugs alone ranged between 1065 and 3255 μg/mL, the IC50 resulting from the combination of abietic acid and fluconazole ranged between 7563 and 160.1 μg/mL. Whether used in combination with fluconazole or isolated, abietic acid exhibited Minimum Fungicidal Concentration (MFC) values exceeding 1024 μg/mL against Candida albicans, Candida krusei and Candida tropicalis. However, it was observed that the antifungal effect of fluconazole was enhanced when used in combination with abietic acid against Candida albicans and Candida tropicalis. These findings suggest that while abietic acid alone has limited inherent antifungal activity, it can enhance the effectiveness of fluconazole, thereby reducing antifungal resistance.

Physico-Chemical Characterization, Phenolic Compound Extraction and Biological Activity of Grapevine (Vitis vinifera L.) Canes

Annual grapevine pruning produces large amounts of unused waste as woody canes. The current study is aimed at the sustainable valorization of viticultural waste by establishing phenolic compound extraction conditions, composition, and biological potential of crude and purified cane extracts of three Vitis vinifera L. cultivars growing in temperate climate conditions. Grapevine canes proved to be rich in carbohydrates and minerals; chlorophyll and carotenoids were also quantified. The highest yield of phenolic compounds was obtained when dry canes (&lt;0.5 mm) were subjected to liquid–solid extraction (1:20 w/v) with 70% (v/v) ethanol, for 4 h at 35 °C, after a preliminary ultrasound treatment (6 min., 42 KHz); Pinot Gris canes showing the highest concentration of flavonoids and non-flavonoids. Stilbenes (resveratrol) and flavan-3-ols (catechin and epicatechin) were the main phenolic representative, resveratrol concentrations varying significantly between red-black (419.01–425.60 μg/g d.w.) and white (282.19 ± 4.14 μg/g d.w.) grape cultivars. Purified extracts (C-18 cartridge) exhibited higher antioxidant and antiradical activities compared to the crude extracts, and a higher antimicrobial effect, especially against Gram-positive (Staphylococcus aureus) pathogenic bacteria. Furthermore, Saccharomyces cerevisiae and Oenococcus oeni showed a reduced susceptibility even at high extract concentrations (&gt;100 mg/mL). These findings indicate that grapevine canes represent a valuable source of natural bioactive compounds, that are currently insufficiently known and not exploited to their true functional and economic potential.

Changes in brown adipose tissue induced by resveratrol and its analogue pterostilbene in rats fed with a high-fat high-fructose diet

Natural bioactive compounds have attracted a great deal of attention since some of them can act as thermogenesis activators. In recent years, special interest has been placed on resveratrol and its analogue pterostilbene, a dimethylether derivative that shows higher bioavailability. The aim of the present study is to compare the effects of resveratrol and its derivative pterostilbene on the thermogenic capacity of interscapular brown adipose tissue (iBAT) in rats under a high-fat high-fructose diet. Rats were divided into four experimental groups: control, high-fat high-fructose diet (HFHF) and HFHF diet supplemented with 30 mg/kg body weight/day of pterostilbene (PT30) or resveratrol (RSV30), for eight weeks. Weights of adipose tissues, iBAT triglycerides, carnitine palmitoyltransferase 1A (CPT1A) and citrate synthase (CS) activities, protein levels of uncoupling protein 1 (UCP1), sirtuins (SIRT1 and 3), AMP-activated protein kinase (AMPK), glucose transporter (GLUT4), fatty acid synthase (FAS), nuclear respiratory factor (NRF1), hormone-sensitive lipase (HSL), adipose triglyceride lipase (ATGL), CD36 and FATP1 fatty acid transporters, peroxisome proliferator-activated receptor gamma coactivator 1 (PGC1) activation and the batokines EPDR1 and NRG4 were assessed in iBAT. The results show that some key proteins related to thermogenesis were modified by either pterostilbene or resveratrol, although the lack of effects on other crucial proteins of the thermogenic machinery suggest that these compounds were not able to stimulate this process in iBAT. Overall, these data suggest that the effects of stilbenes on brown adipose tissue thermogenic capacity depend on the metabolic status, and more precisely on the presence or absence of obesity, although further studies are needed to confirm this hypothesis.

Analysis of Natural Bioactive Compounds in Plant, Food, and Pharmaceutical Products Using Chromatographic Techniques

A growing tendency toward the discovery and use of natural bioactive compounds that are the least harmful, have the fewest side effects, and are the most natural for the human body has been noticed during the past few decades [...]

UVB treatments of packaged ready-to-eat salads: Induced enhancement of quercetin derivatives in baby-leaf lettuce (Lactuca sativa L.) and wild rocket (Diplotaxis tenuifolia L.)

Ready-To-Eat (RTE) salads conveniently pre-prepared in bags can promote the intake of natural bioactive compounds, including antivirals such as quercetin. However, the content of these compounds in the species used for RTE salads is usually low due to limited solar UV exposure under tunnels and greenhouses in which they are usually cultivated. To address this, we treated commercial fresh-cut lettuce (Lactuca sativa L.) and wild rocket (Diplotaxis tenuifolia L.) leaves using a narrow-band UVB lamp directly through sealed polypropylene bags during storage (5–6 °C, 80% RH). The bagged leaf samples were kept under 20 µmol m−2 s−1 of white light with a 12 h photoperiod for 6 d. Half of the samples were additionally treated, 9 h d−1, during the first 3 d by UVB narrow-band lamps delivering 2.8–3.6 μmol m−2s−1 of UVB and 0.8–1.0 μmol m−2s−1 of UVA radiation. The effects of the UVB treatments on epidermal phenolics, chlorophyll and photosynthetic parameters were monitored daily by non-destructive fluorescence sensors over a 6-d storage period. At the end of the experiment, destructive HPLC-DAD analysis of phenolics and photosynthetic pigments, antioxidant capacity assays and fresh weight loss determinations were conducted. The UVB-treatment increased the epidermal phenolics (EPhen) Index with respect to unirradiated controls, while not affecting chlorophyll and carotenoids levels as well as photosynthetic efficiency. For both species, the EPhen Index changes were detected 15 h after the first UVB application. Then, wild rocket responded faster than baby-leaf lettuce and reached the maximal phenolic level with less than 1/3 of the energy dose needed by lettuce. UVB-treated samples exhibited higher flavonoid concentrations (mainly quercetin derivatives) compared to controls (48–67% and 37–66% in lettuce and wild rocket, respectively). Leaf chlorophyll and carotenoid contents were not affected by both UVB treatment and storage. We proved, for the first time, that it is possible to treat RTE salad leaves using through-packaging UVB radiation and enhance their total phenolic and quercetin derivative contents. We also provided more insights concerning the dynamics of the UVB-elicitation of phenolic compounds in postharvest leaves. Our results are propaedeutic for the optimization of potential UVB-treatments; selection of the most efficient wavelengths, intensity, single/multiple doses and proposals for application in the food industry.

Optimization of experimental conditions for bioactive compounds recovery from raspberry fruits (Rubus idaeus L.) by using combinations of ultrasound-assisted extraction and deep eutectic solvents

Raspberry fruits (Rubus idaeus L.) have been reported to contain phenolic compounds, of which anthocyanins are the most abundant. A novel procedure of ultrasound-assisted extraction (UAE) using deep eutectic solvent (DES) for efficient extraction phenolic compounds and anthocyanins from raspberries is considered. Namely, the green approach for optimization by response surface methodology (RSM) based on Box-Behnken Design (BBD) was proposed in this study. Three carboxylic acid-based DES, like acetic acid/glucose (DESAAGLU), formic acid/glucose (DESFAGLU), and lactic acid/maltose (DESLAMA), were tested for their efficiency in the recovery of phenolic compounds and anthocyanins from raspberries. The optimum extraction parameters were obtained; extraction time of 60 min, a solvent volume of 35 mL, and added water on DES of 30 mL (v/v). The results of this study indicated that optimizing extraction conditions are critical for quantifying phenolic compounds and anthocyanins. The present model can contribute to finding a cheap way of delivering natural bioactive compounds in the food, cosmetic, and pharmaceutical industriesas well as a natural food colorant in dietary applications with potential health benefits.