Assessing the In Vitro Inhibitory Effects on Key Enzymes Linked to Type-2 Diabetes and Obesity and Protein Glycation by Phenolic Compounds of Lauraceae Plant Species Endemic to the Laurisilva Forest.

Methanolic leaf extracts of four Lauraceae species endemic to Laurisilva forest (Apollonias barbujana, Laurus novocanariensis, Ocotea foetens and Persea indica) were investigated for the first time for their potential to inhibit key enzymes linked to type-2 diabetes (α-amylase, α-glucosidase, aldose reductase) and obesity (pancreatic lipase), and protein glycation. Lauraceae extracts revealed significant inhibitory activities in all assays, altough with different ability between species. In general, P. indica showed the most promissing results. In the protein glycation assay, all analysed extracts displayed a stronger effect than a reference compound: aminoguanidine (AMG). The in vitro anti-diabetic, anti-obesity and anti-glycation activities of analysed extracts showed correlation with their flavonols and flavan-3-ols (in particular, proanthocyanins) contents. These Lauraceae species have the capacity to assist in adjuvant therapy of type-2 diabetes and associated complications, through modulation of the activity of key metabolic enzymes and prevention of advanced glycation end-products (AGEs) formation.

Release of health-related compounds during in vitro gastro-intestinal digestion of okara and okara fermented with Lactobacillus plantarum.

Okara is a highly perishable by-product remaining after filtration of the smashed soybeans seeds in the production of soymilk. Due to its nutritional value, different approaches have been developed to use it as functional ingredient. Fermentation of okara appears as an interesting strategy to preclude spoilage, providing a more stable matrix to be incorporated in the formulation of functional foods. Okara has antioxidant compounds but the effect of fermentation, and their bioaccessibility still need to be investigated. To achieve this aim, the phenolic compounds (as determined by TPC and TFC assays) and the antioxidant properties (as determined by ABTS ·+, DPPH · , O2 ·- assays) of okara and okara fermented with Lactobacillus plantarum CIDCA 83114 were assessed both before and after exposure to simulated gastro-intestinal conditions. Before digestion, okara showed higher values of TPC and TFC than the fermented counterpart. Although a decrease of TPC and TFC was observed after exposing okara to gastric conditions, no significant differences between okara and fermented okara were detected. No further decrease of TPC were observed in intestinal conditions. Okara showed higher antioxidant activity than fermented okara. There was a considerable decrease in the antioxidant activity for both samples when exposed to gastric and intestinal conditions. A good correlation between TFC and antioxidant activities was detected, suggesting that flavonoids play an important role as antioxidants. As a whole, this work provides a solid support for the stability of phytochemicals along the digestive process of both okara and fermented okara.

Phytochemical Profile, Chemotaxonomic Studies, and In Vitro Antioxidant Activities of Two Endemisms from Madeira Archipelago: Melanoselinum decipiens and Monizia edulis (Apiaceae).

Melanoselinum decipiens and Monizia edulis (Apiaceae) are two endemic plants from Madeira archipelago, phytochemical compositions of which remains little explored, despite their use in folk medicine. Using liquid chromatography with diode array and electrospray ionization/mass spectrometry analysis, their polyphenolic profile was established for the first time. Fifty-six compounds were identified with 5-O-caffeoylquinic acid, quercetin-O-(malonyl)hexoside, luteolin diacetyl, and quercetin-O-hexoside being the major constituents in the leaves of both plant species (≥ 0.76 mg/g of dry extract). Principal component analysis provided a suitable tool to differentiate targeted plants. Naringenin-6,8-di-C-glucoside, quercetin 3-O-pentosylhexoside, and 1,5-O-dicaffeoylquinic acid can be used as discriminatory taxonomic/geographical markers for M. edulis subspecies from Madeira and Porto Santo populations. This methodology of using polyphenols as chemotaxonomic markers proved to be useful for identification of plant species since the results are consistent with previous taxonomical data. The free-radical scavenging activities of the M. decipiens extracts proved to be higher than those of M. edulis, which correlated well with their phenolic content (R2  > 0.906).

Flavonoids as Insecticides in Crop Protection-A Review of Current Research and Future Prospects.

Pesticide overuse in agricultural systems has resulted in the development of pest resistance, the impoverishment of soil microbiota, water pollution, and several human health issues. Nonetheless, farmers still depend heavily on these agrochemicals for economically viable production, given the high frequency at which crops are affected by pests. Phytopathogenic insects are considered the most destructive pests on crops. Botanical pesticides have gained attention as potential biopesticides and complements to traditional pesticides, owing to their biodegradability and low toxicity. Plant-based extracts are abundant in a wide variety of bioactive compounds, such as flavonoids, a class of polyphenols that have been extensively studied for this purpose because of their involvement in plant defense responses. The present review offers a comprehensive review of current research on the potential of flavonoids as insecticides for crop protection, addressing the modes and possible mechanisms of action underlying their bioactivity. The structure-activity relationship is also discussed. It also addresses challenges associated with their application in pest and disease management and suggests alternatives to overcome these issues.

A Two-Step Approach to Orange Peel Waste Valorization: Consecutive Extraction of Pectin and Hesperidin.

Citrus consumption translates into large amounts of residue, the disposal of which is associated with environmental issues and high costs. Current trends in citrus waste focus on the extraction of highly valued bioactive compounds via single-compound extraction. There is a lack of knowledge on how these methodologies can be introduced into extraction schemes of bioactive compounds, maximizing the residue potential and reducing its amount. The present work aimed to address this issue by designing a consecutive extraction of pectin and hesperidin from orange peel waste. A novel method for extraction and precipitation of hesperidin with an eco-friendly approach is also presented. After neutral pretreatment, pectin extraction was conducted under acidic conditions, followed by hesperidin extraction with a drastic pH change. Pectin had a high AUA content (66.20 ± 1.25%), meeting the criteria for use in the food industry. The best-tested conditions for hesperidin extraction (30 min, 70 °C, 1:10 (w/v)) provided a yield of 1% and a purity of 84%. The designed extraction scheme shows the potential of citrus waste as a source of bioactive compounds of good quality and high interest in the food industry while following the principles of green chemistry and circular economy.

Spectrochemical analysis of seasonal and sexual variation of antioxidants in Corema album (L.) D. Don leaf extracts.

Bioactive phytoconstituents have been increasingly investigated for their potential human health benefits. Corema album (L.) D. Don, an Ericaceae, reportedly has antioxidant, antimicrobial and anticancer properties. Aiming at enhancing its nutraceutical potential, we performed a spectrochemical analysis of hydroethanolic extracts from C. album leaves. We report on changes in the antioxidant activity of the extracts, as well as in the accumulation of key phytoconstituents (namely phenolic compounds), in female and male samples, throughout three harvesting seasons (February, July, and October). For each extract, the antioxidant activity was assessed by different spectrophotometric methods. Simultaneously, attenuated total reflectance Fourier transform mid-infrared spectroscopy (FTIR-ATR), and high-performance liquid chromatography - electrospray ionisation - quadrupole time-of-flight mass spectrometry (HPLC-ESI-Q-TOF-MS), were used to identify and monitor variations in the composition of phenolic compounds in the extracts. The main compounds identified were epicatechin, laricitrin-O-hexoside isomers, and myricetin-O-hexoside isomers. Significant differences were found in the composition and relative abundance of the compounds of interest, according to sex and season. Overall, a trend was observed whereby phenolic content and antioxidant activities were higher in males and increased between the earlier and the latest harvests. Based on these results, we may conclude that late summer or early autumn harvests are preferable when aiming at the highest yearly content of bioactive compounds. Additionally, it should be considered that extracts from male individuals typically display higher antioxidant activities. Ultimately, our understanding of C. album in the context of nutraceutical applications is benefited from the quantitative and qualitative portrait provided here, thus promoting its relevance as a source of bioactive compounds.

An improved and fast UHPLC-PDA methodology for determination of L-ascorbic and dehydroascorbic acids in fruits and vegetables. Evaluation of degradation rate during storage.

This study provides a versatile validated method to determine the total vitamin C content, as the sum of the contents of L-ascorbic acid (L-AA) and dehydroascorbic acid (DHAA), in several fruits and vegetables and its degradability with storage time. Seven horticultural crops from two different origins were analyzed using an ultra-high-performance liquid chromatographic-photodiode array (UHPLC-PDA) system, equipped with a new trifunctional high strength silica (100% silica particle) analytical column (100 mm × 2.1 mm, 1.7 µm particle size) using 0.1% (v/v) formic acid as mobile phase, in isocratic mode. This new stationary phase, specially designed for polar compounds, overcomes the problems normally encountered in HPLC and is suitable for the analysis of large batches of samples without L-AA degradation. In addition, it proves to be an excellent alternative to conventional C18 columns for the determination of L-AA in fruits and vegetables. The method was fully validated in terms of linearity, detection (LOD) and quantification (LOQ) limits, accuracy, and inter/intra-day precision. Validation experiments revealed very good recovery rate of 96.6 ± 4.4% for L-AA and 103.1 ± 4.8 % for total vitamin C, good linearity with r(2)-values >0.999 within the established concentration range, excellent repeatability (0.5%), and reproducibility (1.6%) values. The LOD of the method was 22 ng/mL whereas the LOQ was 67 ng/mL. It was possible to demonstrate that L-AA and DHAA concentrations in the different horticulture products varied oppositely with time of storage not always affecting the total amount of vitamin C during shelf-life. Locally produced fruits have higher concentrations of vitamin C, compared with imported ones, but vegetables showed the opposite trend. Moreover, this UHPLC-PDA methodology proves to be an improved, simple, and fast approach for determining the total content of vitamin C in various food commodities, with high sensitivity, selectivity, and resolving power within 3 min of run analysis.

Helichrysum monizii Lowe: phenolic composition and antioxidant potential.

INTRODUCTION: In Madeira Archipelago there are four endemic Helichyrsum species and three of them are used in the traditional medicine. Helichrysum monizii is a rare endemism with very scarce information available concerning its uses in the local traditional medicine. OBJECTIVE: The aim of this work was to study for the first time Helichrysum monizii in terms of its antioxidant capacity and the identification of the phenolic compounds to which that activity is due. METHODOLOGY: Three different methods of extraction were performed and total phenolic and flavonoid contents of extracts were correlated to radical scavenging and antioxidant capacity by DPPH, ABTS, FRAP and ß-carotene assays. An HPLC-DAD-ESI/MS(n) method was employed for the separation and identification of the phenolic and flavonoid components. RESULTS: The results revealed a high antioxidant potential mainly related to the phenolic profile of the plant. Polar components of methanol extracts of Helichrsyum monizii were detected by a high-performance liquid chromatography/electrospray ionisation tandem mass spectrometry (HPLC-DAD-ESI/MS(n) ) method. Thirty-three compounds were identified and 19 of them were identified as quinic acid derivatives. CONCLUSIONS: The high antioxidant potential Helichrysum monizii was for the first time established. Dicaffeoylquinic acids are the main responsible for that activity.

Characterization of phenolic compounds in Helichrysum melaleucum by high-performance liquid chromatography with on-line ultraviolet and mass spectrometry detection.

Helicrysum melaleucum is a medicinal plant traditionally used in the islands of the Macaronesia region for the treatment of respiratory diseases. In this work, the phenolic compounds of Helicrysum melaleucum plants collected in different geographical locations of Madeira Island and their morphological parts (total aerial parts, leaves, flowers and stems) were extracted and analyzed separately by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-DAD/ESI-MS(n)). A total of 68 compounds were characterized based mainly on their UV and mass spectra. These included derivatives of O-glycosylated flavonoids (flavonol and flavones type), quinic acid, caffeic acid, lignans and polyphenols. The flowers were found to be the morphological part with higher variety of phenolic compounds. The large differences in the phenolic composition of plants collected from different geographical locations allowed the identification of a few components, such as pinoresinol and methoxylated flavone derivatives, likely to be useful as geographical markers. Also, these results promote further comparison of the bioactivities of the different samples analyzed. This paper marks the first report on the chemical analysis of Helichrysum melaleucum species.

A Novel and Simpler Alkaline Hydrolysis Methodology for Extraction of Ferulic Acid from Brewer's Spent Grain and its (Partial) Purification through Adsorption in a Synthetic Resin.

This work aims to develop simpler methodologies of extracting ferulic acid (FA) from brewer's spent grain (BSG). BSG is produced by brewing companies at high amounts all over the year and does not possess a direct application. Thus, its use as raw material for extraction of bioactive compounds has gained attention in the last years. FA has different interesting applications in cosmetics, food industry, and pharmaceutics. Several studies aim for its extraction from BSG by various methods, namely alkaline hydrolysis. In the present work, we suggest the use of autoclave to process higher amounts of BSG in a lab scale. A simplification of the regular post-hydrolysis procedures is also proposed to decrease the number of experimental steps and energy costs and to simultaneously increase the extraction yield (up to 470 mg of FA per 100 g of BSG). The adsorption of extracted FA in a synthetic resin is suggested as a partial purification method.

Phenolic Profile, Toxicity, Enzyme Inhibition, In Silico Studies, and Antioxidant Properties of Cakile maritima Scop. (Brassicaceae) from Southern Portugal.

Cakile maritima Scop. (sea rocket) is an edible halophyte plant with several ethnomedicinal uses. This work reports the chemical profile and bioactivities of food grade extracts from sea rocket organs. Toxicity was determined on mammalian cells, and phenolic profiling and the quantitation of the main metabolites were made by high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS). Enzymatic inhibition was determined towards acetyl- and butyrylcholinesterase (AChE, BuChE), α-glucosidase, α-amylase, and tyrosinase. Docking studies were performed to tyrosinase, on the major metabolites, and samples were tested for antioxidant properties. Extracts were not toxic, were constituted mainly by flavonoids, and some compounds (roseoside and oleuropein) are here described for the first time in the species. The aerial organs' ethanol extract had relevant activity towards 2,2-diphenyl-1-picrylhydrazyl [DPPH, half maximal inhibitory concentration (IC50) = 0.59 mg/mL], and ferric-reducing activity power (FRAP, IC50 = 0.99 mg/mL). All samples were more active towards AChE than on BuChE. The ethanol fruits' extract inhibited α-glucosidase [2.19 mmol of equivalent of acarbose (ACAE)/g]. Samples were active against tyrosinase, especially the aerial organs' ethanol extracts [25.9 mg of equivalent of kojic acid (KAE)/g]. Quercetin and kaempferol glycosides fit well into the enzymatic pocket of tyrosinase. Our results suggest sea rocket as a candidate to be further explored as a source of bioactive products.

Analysis of phenolic compounds from different morphological parts of Helichrysum devium by liquid chromatography with on-line UV and electrospray ionization mass spectrometric detection.

A simple and rapid method has been used for the screening and identification of the main phenolic compounds from Helichrysum devium using high-performance liquid chromatography with on-line UV and electrospray ionization mass spectrometric detection (LC-DAD/ESI-MS(n)). The total aerial parts and different morphological parts of the plant, namely leaves, flowers and stems, were analyzed separately. A total of 34 compounds present in the methanolic extract from Helichrysum devium were identified or tentatively characterized based on their UV and mass spectra and retention times. Three of these compounds were positively identified by comparison with reference standards. The phenolic compounds included derivatives of quinic acid, O-glycosylated flavonoids, a caffeic acid derivative and a protocatechuic acid derivative. The characteristic loss of 206 Da from malonylcaffeoyl quinic acid was used to confirm the malonyl linkage to the caffeoyl group. This contribution presents one of the first reports on the analysis of phenolic compounds from Helichrysum devium using LC-DAD/ESI-MS(n) and highlights the prominence of quinic acid derivatives as the main group of phenolic compounds present in these extracts. We also provide evidence that the methanolic extract from the flowers was significantly more complex when compared to that of other morphological parts.

Madeira moneywort (Sibthorpia peregrina L.) as a new source of verbascoside and its derivatives with potential phyto-pharmaceutical applications.

The qualitative and quantitative characterization of Madeira moneywort (Sibthorpia peregrina L.) compounds was investigated for the first time. The antioxidant activity and the effect of the methanolic extract on digestive enzymes activity linked to type-2 diabetes and obesity were also determined by in vitro assays. A total of 56 components were characterized in S. peregrina. Phenylethanoids glycosides (PhEGs) represented the main classes of compounds (95.23 mg g-1 of dry extract), almost all verbascoside and its derivatives (up to 98.85% of the total individual phenolic content). The analysed sample was active against ABTS, DPPH, nitric oxide and superoxide radicals, suggesting a potential beneficial effect against oxidative stress. In addition, the methanolic extract was able to inhibit the catalytic activity of α-, ß-glucosidases, α-amylase and pancreatic lipase. Overall, S. peregrina showed good perspectives to be explored as a rich source of verbascoside and its derivatives for nutraceutical/pharmaceutical products.

Polyphenols of Myrica faya inhibit key enzymes linked to type II diabetes and obesity and formation of advanced glycation end-products (in vitro): Potential role in the prevention of diabetic complications.

Myrica faya Aiton (fire tree, faya) is an underused species with a diverse flavonoid composition (anthocyanins, flavonols, ellagitannins) which can promote positive effects on human health. M. faya has been reported to possess high antioxidant activities, but its potential in the prevention of type II diabetes has not been evaluated so far. In the present study, eight M. faya samples from different areas of Madeira and Azores archipelagos (Portugal) were collected to determine their phytochemical profile and then tested for their in vitro anti-diabetic and antioxidant activities. The analyzed extracts showed strong inhibitory activities towards α -glucosidase, aldose reductase and glycation of bovine serum albumin (BSA) and moderate effects towards α-amylase and lipase (by comparison with reference compounds). Cyanidin-3-O-glucoside and ellagitannins were the main bioactive agents involved in the anti-diabetic effects of M. faya. Such results may provide important scientific evidence for further utilization of M. faya as dietary or nutraceutical products for the prevention and/or control of hyperglycaemia-associated complications.

Evaluation of Rubus grandifolius L. (wild blackberries) activities targeting management of type-2 diabetes and obesity using in vitro models.

Rubus grandifolius Lowe (wild blackberries) is an endemic species from Madeira Archipelago (Portugal) used in folk medicine for alleviating diabetic complications. In this work, R. grandifolius methanolic extracts were analysed for in vitro inhibitory effect on digestive enzymes linked to type-2 diabetes, as well as aldose reductase activity and protein glycation. The phenolic composition, antioxidant and cytotoxic activities were also determined. Methanolic extracts exhibited strong inhibition of glucosidases (α- and ß), but were less potent for α-amylase and pancreatic lipase when compared to current pharmaceutical drugs. The total phenolic content determined by HPLC-DAD varied between 92.96 - 97.47 and 118.01-137.41 mg g-1 of dry extract for berries and leaves, respectively. Fifty polyphenols were quantified, anthocyanins and ellagitannins being the main compounds. Cyanidin-3-glucoside was identified as one of the main hypoglycaemic and hypolipidemic agents in all extracts. R. grandifolius also prevented glycation of bovine-serum albumin (BSA) and showed strong radical scavenging activity against tested free radicals. At low concentration, the extracts were not cytotoxic against Caco-2 cells. Based on the results of this study, wild blackberry extracts demonstrated a potential beneficial effect on the control/management of type-2 diabetes mellitus, validating their use in folk medicine.

Changes in the phenolic compositions of Elaeagnus umbellata and Sambucus lanceolata after in vitro gastrointestinal digestion and evaluation of their potential anti-diabetic properties.

In this work, the phenolic composition of E. umbellata leaves and berries is reported. Berries were rich in flavonols, whereas leaves presented abundant flavonols and ellagitannins. Then, the enzyme-inhibitory properties, anti-glycation and antioxidant activities of E. umbellata and Sambucus lanceolata (its phenolic profile has been already established in a previous work) were tested by several in vitro assays and compared. The simulated gastrointestinal digestion resulted in a decrease on their phenolic composition. Nevertheless, both species still had the ability to inhibit aldose reductase activity and protein glycation and scavenge free radicals at the end of the process. Thus, the potential beneficial effects of E. umbellata and S. lanceolata seems to be kept to some extent after passage throughout the digestive system. Altogether, this study provides further insight into investigation of these species as dietary sources of bioactive compounds to lower the risk of type-2 diabetes and obesity.

Technological Aspects of the Production of Fructo and Galacto-Oligosaccharides. Enzymatic Synthesis and Hydrolysis.

Fructo- and galacto-oligosaccharides (FOS and GOS) are non-digestible oligosaccharides with prebiotic properties that can be incorporated into a wide number of products. This review details the general outlines for the production of FOS and GOS, both by enzymatic synthesis using disaccharides or other substrates, and by hydrolysis of polysaccharides. Special emphasis is laid on technological aspects, raw materials, properties, and applications.

Quantification of artemisinin in Artemisia annua extracts by 1H-NMR.

Artemisinin is a polycyclic sesquiterpene lactone that is highly effective against multidrug-resistant strains of Plasmodium falciparum, the etiological agent of the most severe form of malaria. Determination of artemisinin in the source plant, Artemisia annua, is a challenging problem since the compound is present in very low concentrations, is thermolabile and unstable, and lacks chromophoric or fluorophoric groups. The ain of this study was to develop a simple protocol for the quantification of artemisinin in a plant extract using an (1)H-NMR method. Samples were prepared by extraction of leaf material with acetone, treatment with activated charcoal to remove chlorophylls and removal of solvent. (1)H-NMR spectra were measured on samples dissolved in deuterochloroform with tert-butanol as internal standard. Quantification was carried out using the using the delta 5.864 signal of artemisinin and the delta 1.276 signal of tert-butanol. The method was optimised and fully validated against a reference standard of artemisinin. The results were compared with those obtained from the same samples quantified using an HPLC-refractive index (RI) method. The (1)H-NMR method gave a linear response for artemisinin within the range 9.85-97.99 mm (r(2) = 0.9968). Using the described method, yields of artemisinin in the range 0.77-1.06% were obtained from leaves of the A. annua hybrid CPQBA x POP, and these values were in agreement with those obtained using an HPLC-RI.

Antioxidant polyphenols of Madeira sorrel (Rumex maderensis): How do they survive to in vitro simulated gastrointestinal digestion?

In this work, we report the phytochemical profile and antioxidant activity of different morphological parts of Rumex maderensis Lowe (Polygonaceae), a wild leafy-vegetable growing in Madeira Island (Portugal). Methanol extracts from leaves, flowers, and stems were submitted to high-performance liquid chromatography with mass spectrometry detection to obtain the phytochemical profile, which allowed the identification of 86 polyphenols (about 70% C- and O-flavonoids) and 9 non-phenolic compounds. In vitro antioxidant activities were measured against ABTS, DPPH, nitric oxide and superoxide free radicals. Then, the samples were subjected to an in vitro digestion, observing a decrease of about 50% in both the content of phenolics and the antioxidant activity. However, relevant antioxidant capacity was still observed after the simulated digestion. Therefore, this study supports the consumption of R. maderensis as an interesting foodstuff and a dietary source of antioxidant phytochemicals that survive the gastrointestinal digestion process.

Evaluation of Asteraceae herbal extracts in the management of diabetes and obesity. Contribution of caffeoylquinic acids on the inhibition of digestive enzymes activity and formation of advanced glycation end-products (in vitro).

The study was performed to assess, for the first time, the in vitro anti-diabetic potential of ten Asteraceae plant extracts to inhibit the activity of digestive enzymes (α-amylase, α-, ß-glucosidases and lipase) responsible for hydrolysis/digestion of sugar and lipids. Prevention of advanced glycation end-products (AGEs) formation was evaluated in bovine serum albumin/ribose glycation reaction model. The phytochemical profiles and caffeoylquinic acids (CQAs) contents were determined for the methanolic extract of each plant. Analyzed plant extracts exhibited significant inhibitory activity against key digestive enzymes linked to type II diabetes and obesity. A strong inhibition was observed for glucosidases and mild activity towards amylase and lipase (compared to reference compounds). Moreover, some extracts exhibited potent ability to prevent formation of AGEs, implicated in some diabetic complications. Caffeoylquinic acids were dominant in all plant extracts and findings demonstrate that these compounds are the most relevant hypoglycemic and anti-glycation agents. From the obtained results, Argyranthemum pinnatifidum, Helichrysum melaleucum, and Phagnalon lowei are good candidates for further development of phyto-pharmaceutical preparations as complementary therapy for diabetes and obesity control.