GC/MS and LC-MS/MS phytochemical evaluation of the essential oil and selected secondary metabolites of Ajuga orientalis from Jordan and its antioxidant activity

The current investigation aimed to shed light in the volatile and non-volatile secondary metabolites of Ajuga orientalis L. from Jordan. GC/MS and GC/FID analysis of the hydrodistilled essential oil obtained from aerial parts of the plant revealed tiglic acid (18.90 %) as main constituent. Each of the methanol and butanol fractions of A. orientalis were screened for their total phenol content (TPC), total flavonoid content (TFC), and antioxidant activity determined by DDPH and ABTS methods. The extracts were then analyzed by LC-ESI-MS/MS to unveil their chemical constituents, especially phenols and flavonoids. Results showed that the AO-B extract had the highest TPC (217.63 ± 2.65 mg gallic acid/g dry extract), TFC (944.41 ± 4.77 mg quercetin /g dry extract), highest DPPH and ABTS antioxidant activity ((4.00 ± 0.20) × 10^-2; (3.00 ± 0.20) × 10^-2 mg/mL, respectively) as compared to the AO-M extract. LC-ESI-MS/MS analysis of both extracts revealed the presence of several phenolics, flavonoids and nonphenolic acids.     

Green and highly extraction of phenolic compounds and antioxidant capacity from kinkeliba (Combretum micranthum G. Don) by natural deep eutectic solvents (NADESs) using maceration,ultrasound-assisted extraction and homogenate-assisted extraction

Kinkeliba (C. micranthum) is a tropical plant widely used for its tremendous phytochemicals and biological activities. In the present study, three green carboxylic acid-based natural deep eutectic solvents (NADESs) were used to assess the extraction of phenolic compounds in terms of total phenolic content (TPC), total flavonoid content (TFC), individual phenolic compounds and antioxidant capacity (DPPH and FRAP assays) from dried C. micranthum leaves. For the synthesis of NADESs choline chloride was used as hydrogen bond acceptors (HBA) in combination with lactic acid (ChLa), acetic acid (ChAa) and tartaric acid (ChTa) as hydrogen bond donors (HBDs). The conventional solvents including distilled water, pure methanol and pure ethanol were used for comparison. Three extraction methods including maceration extraction (ME), homogenate-assisted extraction (HAE) and ultrasound-assisted extraction (UAE) were tested to determine the best extraction conditions. The solvents combined with the extraction methods were successfully applied for the recovery of phenolic compounds from C. micranthum leaves. ChLa exhibited the highest performance giving the TPC (21.12 ± 0.13–23.62 ± 0.58 mg GAE/g, followed by ChAc (15.49 ± 0.13–18.85 ± 0.39 mg GAE/g), water (17.08 ± 0.32–18.13 ± 0.13 mg GAE/g), ChTa (14.49 ± 0.26–17.44 ± 0.19 mg GAE/g), methanol (7.46 ± 0.45–11.64 ± 0.32 mg GAE/g) and ethanol (2.88 ± 0.39–4.60 ± 0.39 mg GAE/g), respectively. For TFC, ChLa (4.38 ± 0.09–5.01 ± 0.09 mg ECE/g) was the most prominent solvent, followed by ChAc (2.84 ± 0.04–5.01 ± 0.36 mg ECE/g), methanol (1.93 ± 053–4.85 ± 0.04 mg ECE/g), ethanol (1.49 ± 0.36–4.16 ± 0.04 mg ECE/g), ChTa (1.09 ± 0.04–3.22 ± 0.13 mg ECE/g) and water (1.15 ± 0.04–1.37 ± 0.44 mg ECE/g), respectively. The acidic NADESs especially ChLa and ChAa exhibited the best efficiencies compared to the conventional solvents. Furthermore, UAE and HAE provided good extraction efficiency in a short extraction time (30 min) in terms of the TPC, TFC, individual phenolic compounds and the antioxidant capacity compared to ME which gave a similar yield with 12 h of extraction time. Principal component analysis (PCA) showed that C. micranthum extracts could clearly be discriminated in terms of phytochemical compounds and antioxidant capacity and UAE, HAE or ME combined with ChLa ChAc or ChTa were the best choices to higher extraction efficiency.     

Metabolic variations in seaweed,Sargassum polycystum samples subjected to different drying methods via 1H NMR-based metabolomics and their bioactivity in diverse solvent extracts

Seaweeds are known as excellent sources of unique bioactive metabolites. In the present study, proton nuclear magnetic resonance (¹H NMR) combined with principal component analysis (PCA) was used to distinguish the metabolic variations in Brown seaweed, Sargassum polycystum treated under different drying processes. The study also evaluated the phytochemistry, antioxidant, and antimicrobial effects of S. polycystum extracted in different solvents. Mutually under the different drying processes investigated, a total of 12 metabolites were identified from ¹H NMR analysis. Freeze drying emerged as the most efficient process that preserved most of the potentially beneficial metabolites in the samples. The results of the qualitative phytochemical screening of differentially dried S. polycystum extracts revealed the presence of various secondary metabolites. The 70% ethanol extract exhibited the highest total phenolic (627 ± 50.81 mg GAE/100 g dried samples) and also displayed the highest DPPH scavenging activity (61.4 ± 0.171%) at the highest concentration (3 mg ml⁻¹) tested. Methanol extract on the other hand contained the highest total antioxidant capacity (121.00 ± 0.003 mmol/g) followed by 70% ethanol extract (120.00 ± 0.001 mmol/g) at concentration of 1.25 mg/mL. The 70% ethanol extract also showed inhibition zone towards all bacteria samples tested compared to others solvent extracts. Based on these results, the identification of metabolites variations using PCA is considered as very useful procedure as a basis to recommend the most efficient processing (drying) method. The potential utilization of the tested Brown seaweed S. polycystum species as a source of antioxidants and antibacterial agents were also highlighted. The commercial cultivation of the species therefore, needs to be encouraged and promoted.     

Polarity-guided phytochemical extraction,polyphenolic characterization,and multimode biological evaluation of Seriphidium kurramense (Qazilb.) Y. R. Ling

Purpose of studyThe undertaken study aims to assess the polyphenolic profile, and antioxidant, antimicrobial, antiviral, antidiabetic, and cytotoxic potential of Seriphidium kurramense (Qazilb.) Y. R. Ling extracts.MethodsExtracts of aerial parts were prepared by successive extraction (n-hexane {Sk-nH}, ethyl acetate {Sk-EA}, methanol {Sk-M} and aqueous {Sk-Aq}). Chromogenic assays determined the antioxidant profile while HPLC quantified several polyphenols. Agar well diffusion was employed for antimicrobial potential while brine shrimp and hemolytic assays established the biosafety profile.ResultsThe results have shown that maximum extract recovery (17.49% w/w), total phenolics content (24.44 ± 0.15 μg GAE/mgE), and total flavonoids content (6.87 ± 0.25 μg QE/mgE) were recorded in Sk-Aq. RP-HPLC quantified a significant amount of syringic acid (1.43 ± 0.05 µg/mgE), caffeic acid (0.48 ± 0.02 µg/mgE), gentisic acid (6.44 ± 0.01 µg/mgE), and quercetin (4.39 ± 0.01 µg/mgE) in Sk-Aq, while maximum amounts of thymoquinone (0.21 ± 0.02 µg/mgE) and luteolin (3.90 ± 0.03 µg/mgE) along with apigenin (3.72 ± 0.03 µg/mgE) existed in Sk-M and highest quantities of ferulic acid (2.98 ± 0.01 µg/mgE), myricetin (1.04 ± 0.02 µg/mgE) and kaempferol (1.23 ± 0.01 µg/mgE) were found to be present in Sk-EA. A substantial free radical scavenging (85.87 ± 1.00%), total reducing power (211.93 ± 0.97 µg AAE/mgE), and urease inhibition activity (87.99 ± 0.19% at 500 µg/ml) were also recorded in the Sk-Aq. The highest antioxidant capacity (243.5 ± 1.12 µg AAE/mgE), antibacterial, antifungal, and antiviral activity (100% reduction in plaque formation at 400 µg/ml) were observed for Sk-EA. Maximum antibacterial and antifungal activities were revealed against Klebsiella pneumoniae (MIC = 25 ± 0.37 µg/ml), and Candida albicans (MIC = 50 ± 0.19 µg/ml) respectively. The prominent antidiabetic potential was displayed by Sk-nH in terms of α-amylase and α-glucosidase inhibition.ConclusionThe results reported, herein suggest that S. kurramense can be a promising candidate for antioxidant, antibacterial, antifungal, antiviral, and antidiabetic secondary metabolites.     

Novel silver-platinum bimetallic nanoalloy synthesized from Vernonia mespilifolia extract: Antioxidant,antimicrobial, and cytotoxic activities

In this study, bimetallic nanoparticles comprising silver and platinum with promising therapeutic activities were synthesized using ethanolic Vernonia mespilifolia plant extract for the first time. The bimetallic silver-platinum nanoparticles (AgPtNPs) were characterized using solid-state techniques including UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX) techniques. The internal morphological structure showed that the AgPtNPs were spherical with a diameter of approximately 35.5 ± 0.8 nm, while FTIR confirmed the effective capping and formation of the nanoparticles by phytoconstituents. The polyphenolic contents of the green synthesized nanoparticles from the ethanolic extract of V. mespilifolia (AgNPs and AgPtNPs) was found to be (28.0 ± 0.8 and 13.6 ± 0.1 mg GAE/g) total phenol, while the flavonoids content was (366.2 ± 17.0 and 126.6 ± 0.2 mg QE/g), and proanthocyanins content was (161.8 ± 0.6 and 70.2 ± 0.6 mg CE/g). The AgPtNPs displayed a greater ability to scavenge free radicals, especially DPPH and ABTS (IC₅₀ 19.5 and 21.6 µg/mL) respectively when compared with AgNPs and ascorbic acid. Besides, the AgPtNPs had a higher ferric reducing antioxidant power (FRAP) (44.1 mg GAE/g) when compared to AgNPs (18.5 mg GAE/g). Moreover, the AgPtNPs showed a two-fold antimicrobial activity towards pathogenic microbes compared to AgNPs and a selective cytotoxic potency towards MCF-7 breast cancer cell line compared to HEK 293 normal cell line. In summary, these fascinating bioactivities displayed by the AgPtNPs highlighted their potential in therapeutic biomedical applications.     

Anti-pathogenic,anti-diabetic,anti-inflammatory,antioxidant, and wound healing efficacy of Datura metel L. leaves

Datura metel L. is an important medicinal plant of Solanaceae family which has extensive pharmacological properties. The present investigation was aimed to identify the presence of phytoconstituents and assess in vitro antibacterial, anti-biofilm, anti-diabetic, anti-inflammatory, antioxidant, cytotoxicity, and wound healing efficacy of D. metel leaves extract. Among different solvent extracts, methanolic extract showed higher amount of phenolic (124.61 ± 0.68 mg GAE/g), alkaloid (88.77 ± 1.01 mg AE/g), flavonoids (42.24 ± 0.18 mg QE/g), and tannins contents (38.72 ± 0.51 mg GAE/g). The extract exhibited not only significantly (P < 0.05) different antibacterial activities against pathogens tested but also showed maximum biofilm inhibition of 94, 88, and 92% against B. subtilis, MRSA, and E. coli, respectively. Anti-diabetic assay depicted 22.55 ± 0.62–79.41 ± 1.13% and 24.31 ± 1.47–72.59 ± 0.22% of α-amylase and α-glucosidase inhibition abilities of methanolic extract, respectively at varied concentrations. The methanolic extract showed potential anti-inflammatory effect (P < 0.05) by showing 28.11 ± 0.13, 34.94 ± 1.11, 55.73 ± 0.42, 73.28 ± 0.72, and 92.62 ± 1.33% of inhibition of protein denaturation at different concentrations with an IC₅₀ value of 52.45 µg/mL. The extract revealed significant (P < 0.05) rate of ABTS scavenging, DPPH degradation, and reducing power assay in a concentration dependent manner. The cytotoxicity assay was demonstrated on L929 mouse fibroblast cell line and found > 90% of cell viability in the presence of methanolic extract, thereby indicating its non-toxicity effect. Wound healing assay indicated that methanolic extract at 50 µg/mL closed 100% of wound gap after 24 h with high rate of migration and proliferation. Furthermore, GC–MS chromatogram revealed the presence of several components in methanolic extract, including neophytadiene, hexadecanoic acid, and hentriacontane as principal phytoconstituents. In conclusion, methanolic extract of D. metel leaves could be used as potent therapeutic agent not only for treating metabolic diseases but also superficial chronic diabetic wounds.     

Conventional and ultrasound-assisted methods for extraction of bioactive compounds from red araçá peel (Psidium cattleianum Sabine)

The present study aimed to maximize the conventional extraction and compare it with the ultrasound-assisted method for extracting bioactive compounds obtained from the red araçá peel. The behavior of anthocyanins related to the pre-treatment of the vegetal matrix, employed solvent, extraction kinetics of both methods, the levels of total phenolic compounds, flavonoids and carotenoids, as well as the antioxidant activity were evaluated. The ultrasound-assisted extraction (40 KHz −154 W and 90 min) had an increase of 12% in the levels of anthocyanins (121.85 Eq. mg of cyanidin-3-glycoside/100 g of peel) and a 25% reduction in time extraction compared to conventional extraction by maceration (116.81 Eq. mg of cyanidin-3-glycoside/100 g of peel) using 90% ethanol, for 2 h, pH 1.5, at 40 °C and mass/volume ratio 1 g/10 mL). Analyses of the total phenolic compounds, flavonoids and carotenoids presented promising results for the ultrasound-assisted and conventional extractions, respectively. Analyzes of total phenolic compounds, flavonoids and carotenoids, show promising results for ultrasound-assisted extractions, respectively, indicating that red araçá is rich in bioactive compounds beneficial to human health, in addition to being considered natural pigments that can be used in food.     

Optimization of Enzyme-Assisted Extraction and Purification of Flavonoids from Pinus koraiensis Nut-Coated Film and Antioxidant Activity Evaluation

Pinus koraiensis nut-coated film is a kind of by-product of nut processing, which has been shown to contain flavonoids, polyphenols, and other substances that can be used to produce natural antioxidant extracts. In this study, response surface methodology (RSM) was used to optimize the extraction process of flavonoids of P. koraiensis nut-coated film (PNF), and macroporous resin HPD600 was used to purify PNF (P-PNF). Its antioxidant activity was examined by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging capacity, oxygen free radical absorption capacity (ORAC), total oxygen radical capture (TRAP), and iron ion reduction capacity. Under the ideal extraction conditions comprising a cellulase dosage of 90 U/g, a material/liquid ratio of 1:20 (g/mL), and an extraction time of 2 h, the PNF yield was 3.37%. Purification conditions were sample concentration of 2.0 mg/mL, pH of 5, water washing volume of 3 bed volume (BV), eluent ethanol concentration of 50%, and volume of 2 BV. The P-PNF recovery was 84.32%, and purity increased from 33.80% to 61.70%. Additionally, P-PNF showed increased antioxidant activity compared to PNF. Cumulatively, this study obtained the optimal values for the process parameters in order to achieve the maximum rates of extraction of PNF for economically optimal production at an industrial scale.     

Inula viscosa (L.) Aiton leaves and flower buds: Effect of extraction solvent/technique on their antioxidant ability,antimicrobial properties and phenolic profile

Abstract

This study was designed to establish the most effective solvent/technique for extracting antioxidant phytoconstituents from leaves and flower buds of Inula viscosa (L.) Aiton (Asteraceae) grown wild in Morocco. Maceration and hot extraction with methanol or water and Soxhlet ethanol extraction were utilized. The antioxidant potential was evaluated in vitro by DPPH, reducing power, and ferrous ions chelating activity assays. I. viscosa leaf and flower bud extracts displayed the strongest effect in the DPPH test, being the Soxhlet ethanol the most active ones (IC₅₀ = 54.24?±?0.21?μg/mL and 39.77?±?0.23?μg/mL); thus, they were selected for further investigations. The antimicrobial efficacy of the Soxhlet ethanol extracts against ATCC and food isolates strains was assayed; the leaf extract showed the best activity, and Candida albicans was the most sensitive strain (MIC = 125?µg/mL). The extracts resulted non-toxic against Artemia salina. Among the phenolics characterised by HPLC-PDA-ESI-MS, hispidulin hexoside, patuletin and spinacetin were identified for the first time.     

In vitro wound healing properties,antioxidant activities,HPLC–ESI–MS/MS profile and phytoconstituents of the stem aqueous methanolic extract of Dracaena reflexa Lam

Column chromatography of the stem aqueous methanolic extract of Dracaena reflexa Lam. (DRSE) led to the isolation of five flavonoids, one phenolic glycoside, one triterpenoid and two steroidal saponins. Furthermore, 44 compounds were tentatively identified in the phytoconstituent profile of DRSE using HPLC–ESI–MS/MS. The antioxidant activity of DRSE was evaluated. In a DPPH radical scavenging assay, DRSE exhibited an IC₅₀ value of 311.6 ± 10.10 μg/ml compared with the IC₅₀ value of the standard Trolox (24.42 ± 0.87 μg/ml). The antioxidant activities of DRSE using ABTS assay and ferric reducing antioxidant power assay were 326.63 μm Trolox equivalents/mg extract and 208.67 μm Trolox equivalents/mg extract, respectively. The wound-healing activity of DRSE was studied by the scratch assay using Human Skin Fibroblast cells. After 24 h DRSE (at 10 and 20 μg/ml) decreased the wound width to 0.55 ± 0.37 and 0.47 ± 0.55 mm, respectively, compared with the wound width in the control cells (0.77 ± 0.17 mm). This result suggested that DRSE improved the wound-healing process by inducing the migration of fibroblasts. Moreover, a docking study was performed to evaluate the binding affinity of the identified phytoconstituents toward GSK-3β relative to the co-crystalized inhibitor and curcumin with the possible involvement of this pathway in the wound-healing activity of the extract.     

A microwave-based extraction method for the determination of sugar and polyols: Application to the characterization of regular and peaberry coffees

The brewing properties of coffee products are defined by the chemical composition in the bean, including sugars and polyols. Some factors, such as coffee species and roasting, may affect the level of these compounds in the bean. A new analytical microwave-assisted extraction (MAE) method has been developed to extract sugars and polyols from the coffee bean. The studied extraction conditions for the MAE were temperature (30–80 °C), solvent composition (0–50% ethanol in water), and solvent-to-sample ratio (10:1–30:1 mL solvent per g sample). A Box-Behnken design was applied to study the effect of extraction variables, and subsequently, the influential variables were optimized by response surface methodology (RSM). In addition to the main effect of the solvent-to-sample ratio, all quadratic effects significantly influenced (p < 0.05) the recovery of sugars and polyols from the coffee beans. RSM suggested the optimized MAE conditions: temperature 52 °C, ethanol concentration in water 18.5%, and solvent-to-sample ratio 17:1. Under the optimum condition, a kinetics study confirmed that 15 min showed high precision and accuracy of the developed method. Ultimately, a real sample application of the developed MAE revealed that the new method successfully described the composition of sugars and polyols in regular and peaberry coffee beans. Additionally, the method also effectively characterized the green and roasted Arabica and Robusta coffee beans.     

Study on Extraction and Antioxidant Activity of Flavonoids from Hemerocallis fulva (Daylily) Leaves

Hemerocallis fulva is a medical and edible plant. In this study, we optimized the ultrasound-assisted extraction (UAE) process of extracting flavonoids from Hemerocallis fulva leaves by single-factor experiments and response surface methodology (RSM). The optimum extraction conditions generating the maximal total flavonoids content was as follows: 70.6% ethanol concentration; 43.9:1 mL/g solvent to sample ratio; 61.7 °C extraction temperature. Under the optimized extraction conditions, the total flavonoid content (TFC) in eight Hemerocallis fulva varieties were determined, and H. fulva (L.) L. var. kwanso Regel had the highest TFC. The cytotoxicity of the extract was studied using the Cell Counting Kit-8 (CCK-8 assay). When the concentration was less than 1.25 mg/mL, the extract had no significant cytotoxicity to HaCaT cells. The antioxidant activity was measured via chemical antioxidant activity methods in vitro and via cellular antioxidant activity methods. The results indicated that the extract had a strong ABTS and •OH radical scavenging activity. Additionally, the extract had an excellent protective effect against H₂O₂-induced oxidative damage at a concentration of 1.25 mg/mL, which could effectively reduce the level of ROS to 106.681 ± 9.733% (p < 0.001), compared with the 163.995 ± 6.308% of the H₂O₂ group. We identified five flavonoids in the extracts using high-performance liquid chromatography (HPLC). Infrared spectroscopy indicated that the extract contained the structure of flavonoids. The results showed that the extract of Hemerocallis fulva leaves had excellent biocompatibility and antioxidant activity, and could be used as a cheap and potential source of antioxidants in the food, cosmetics, and medicine industries.     

Chemical profiling of Aristolochia tagala Cham. leaf extracts by GC-MS analysis and evaluation of its antibacterial activity

Aristolochia tagala Cham. (Aristolochiaceae) is an underexplored medicinal plant traditionally used to treat snakebites, stomachaches, and poisonous bites. In this study, chemical profiling of the petroleum ether, chloroform, ethyl acetate, methanol, and hydro-alcoholic extracts of the plant was investigated by gas chromatography-mass spectrometry. The antibacterial activity of the plant was tested against ten bacterial strains using the agar disc diffusion and microdilution method. In total, forty two compounds were identified from the extracts with neophytadiene, palmitic acid, phytol, trans-δ9-octadecenoic acid, phytyl palmitate, phytyl tetradecanoate, ergost-5-en-3-ol, (3beta,24r)-,z,z-8,10-hexadecadien-1-ol, stigmasterol, and tetrapentacontane as major phytoconstituents. The hydro-alcoholic extract possessed maximum total phenolics (52.58 ± 06 mg GAE/g), total flavonoids (48.66 ± 91 QRE/g), total flavanols (67.20 ± 64 QRE/g) and vitamin E content (31.26 ± 0.05 mg ATE/g). For antibacterial activity, hydro-alcoholic extract of Aristolochia tagala effectively controlled the growth of bacterial strains such as Proteus valgaris (26.3 mm) and Pseudomonas aeruginosa (19.33 mm) and the same extract showed notable minimum inhibitory concentration (MIC) against the growth of bacteria like Escherichia coli (10.93 μg/ml) and Enterobacter aerogenes (43.7 μg/ml). It was determined that, hydro-alcoholic and methanolic extracts Aristolochia tagala leaf found to have a number of bioactive compounds with significant antibacterial activity against the pathogenic bacteria. Further investigations are necessary to isolate and characterize bioactives and to evaluate its therapeutic potential.     

Impact of solvent type,solvent-water concentration,and number of stages on the extraction of coumarin mixture from tamanu (Calophyllum inophyllum) oil and its antioxidant activity

Natural products have been receiving the spotlight from the people of developing and developed countries in recent years due to rising health care expenses and global financial crises. These natural products are the resources for bioactive compounds used in the drug development process. Tamanu seed oil is used for traditional remedies and cosmetic ingredients. The dried seed produces an oil with a yield of 50–75 %. Previous works reported that the seed oil comprised coumarins, one of the eminent groups of phenolics. Coumarins have anticancer, antimicrobial, anti-inflammatory, anticoagulant, antiviral, wound healing properties, and anti-HIV effects. Extraction is often referred to as the sample preparation method as its essential to purify bioactive compounds. In this work, coumarin mixture from tamanu oil was extracted by batchwise multi stages extraction. The effects of solvent used (methanol and ethanol), solvent–water concentration, and the number of stages were studied. The optimal conditions for the extraction of the coumarin mixture were 90 % ethanol and eight stages of extraction, which contributed to 50.73 ± 0.16 % of purity and 92.95 ± 3.76 % of recovery. Also, these conditions removed up to 66 % free fatty acids (FFA) and 100 % triglycerides (TG). It was found that the DPPH inhibition at 400 ppm shows that 90 % ethanol has the highest inhibition (57.72 ± 2.70 %) with an IC₅₀ value of 305 ppm. Moreover, various compounds like pyrrole-2 carboxylate, epicrinamidine, cholestane, and hydroxysclerodin trimethyl ether were also detected in the polar fraction of tamanu oil.     

Bioactive Compounds from Ephedra fragilis: Extraction Optimization,Chemical Characterization,Antioxidant and AntiGlycation Activities

Response surface methodology (RSM) with a Box–Behnken design (BBD) was used to optimize the extraction of bioactive compounds from Ephedra fragilis. The results suggested that extraction with 61.93% ethanol at 44.43 °C for 15.84 h was the best solution for this combination of variables. The crude ethanol extract (CEE) obtained under optimum extraction conditions was sequentially fractionated with solvents of increasing polarity. The content of total phenolic (TP) and total flavonoid (TF) as well as the antioxidant and antiglycation activities were measured. The phytochemical fingerprint profile of the fraction with the highest activity was characterized by using RP-HPLC. The ethyl acetate fraction (EAF) had the highest TP and TF contents and exhibited the most potent antioxidant and antiglycation activities. The Pearson correlation analysis results showed that TP and TF contents were highly significantly correlated with the antioxidant and antiglycation activities. Totally, six compounds were identified in the EAF of E. fragilis, including four phenolic acids and two flavonoids. Additionally, molecular docking analysis also showed the possible connection between identified bioactive compounds and their mechanisms of action. Our results suggest new evidence on the antioxidant and antiglycation activities of E. fragilis bioactive compounds that may be applied in the treatment and prevention of aging and glycation-associated complications.     

An ultrasound-based technique for the analytical extraction of phenolic compounds in red algae

Phenolic compounds are bioactive compounds that are also naturally found in red algae. To determine the level of these compounds in the red algae, spectroscopic or chromatographic determination was applied over the liquid extracts. Therefore, a prior extraction method is needed. The presented study aimed to develop the analytical ultrasound-assisted extraction (UAE) method to extract phenolic compounds from red algae. A Box–Behnken design (BBD) based on five factors included solvent composition (50–90% ethanol in water), extraction temperature (10–60 °C), ultrasonic power (20–100%), pulse duty-cycle (0.2–1.0 s^?1), and solvent-to-sample ratio (10:1 to 30:1) was used to evaluate the effects of the studied factors. Subsequently, response surface methodology (RSM) was performed to define the optimum extraction condition to recover phenolic compounds from the alga matrices. The UAE condition suggested by RSM was: ultrasonic power 100%, pulse duty-cycle 1 s^?1, temperature 52.5 °C, extraction solvent 50% ethanol in water, and solvent-to-sample ratio 30:1. Kinetic studies confirmed 10 min to provide comparable recovery (p > 0.05) than any longer extraction time. The acceptable values validated the developed method for repeatability (CV, 4.8%) and intermediate precision (CV, 5.7%). In addition, the accuracy of the method suggested a complete recovery for two extraction cycles. Furthermore, the method has successfully been applied for a number of samples covering three different red algae species. Fingerprints of each sample based on phenolic composition and levels characterize the type and origin of different red algae species.     

Extraction of Phenolic and Flavonoid Compounds from Mung Bean (Vigna radiata L.) Seed Coat by Pressurized Liquid Extraction

Mung bean seed coat (MBC) is a by-product of the mung bean processing industry. It contains a large number of phenolic compounds with therapeutic anti-inflammatory, anti-diabetic and antioxidant properties. This research aimed to investigate the optimum conditions for phenolic and flavonoid extraction from MBC by pressurized liquid extraction (PLE). Response surface methodology (RSM) was used to study the effects of temperature (80–160 °C), pressure (1200–1800 psi) and ethanol concentration (5–95%) on total phenolic content (TPC), total flavonoid content (TFC) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) scavenging activity (ABTS). Scale-up extraction was also performed. The optimum conditions for extraction were 160 °C, 1300 psi and 50% ethanol. Under optimum conditions, the TPC was 55.27 ± 1.14 mg gallic acid equivalent (GAE)/g MBC, TFC was 34.04 ± 0.72 mg catechin equivalent (CE)/g MBC and ABTS scavenging activity was 195.05 ± 2.29 mg trolox equivalent (TE)/g MBC. The TFC and ABTS scavenging activity of the extracts obtained at the pilot scale (10 L) was not significantly different from the laboratory scale, while TPC was significantly increased. The freeze-dried MBC extract contained vitexin and isovitexin 130.53 ± 17.89, 21.21 ± 3.22 mg/g extract, respectively. In conclusion, PLE was able to extract phenolics, flavonoids with ABTS scavenging activity from MBC with the prospect for future scale-up for food industry.     

Thorough investigation of the oxygen heterocyclic fraction of lime (Citrus aurantifolia (Christm.) Swingle) juice

Reversed‐phase‐HPLC analysis by means of superficially porous silica particle columns (fused‐core) was applied to the investigation of flavonoids, coumarins, and psoralens in lime juice samples. Hesperidin (367.0 ± 16.0 ppm) and eriocitrin (148.0 ± 7.9 ppm) were the most abundant flavonoids. Fifteen coumarins and furocoumarins were determined, including bergamottin (29.6 ± 1.1 ppm), 5‐geranyloxy‐7‐methoxycoumarin (16.5 ± 0.6 ppm), and oxypeucedanin hydrate (9.9 ± 0.5 ppm) as predominant compounds. These molecules are today well known for their beneficial effects on human health. As a consequence, the present study, beyond investigating for the first time the chemical composition of lime juice, highlights also its health‐promoting qualities, due to its content of flavonoids and coumarins.     

Extract with high 1,1-diphenyl-2-picrylhydrazyl (DPPH) inhibitory capability from pericarp and seed of mangosteen (Garcinia mangostana L.) using microwave-assisted extraction (MAE) two-phase solvent technique

The human body needs compounds that are antioxidants to prevent oxidative stress. Some parts of the mangosteen fruit (Garcinia mangostana L.) have been known as sources of bioactive compounds that have antioxidant properties. The pericarp and seeds of mangosteen were extracted using the MAE method to produce the extract with the greatest antioxidant activity. There are two types of solvent mixtures used in the extraction process: single-phase and two-phase solvents. The solvents used were ethanol (EtOH), ethyl acetate (EtOAc), isopropyl alcohol (IPA), and water. First, utilizing dried mangosteen pericarp powder as the raw material, a study was undertaken to determine the ideal operating conditions for the MAE process. A one-factor-at-a-time approach was used to find the best operating conditions. A mixture of solvents with varied ratios (mL/mL), extraction temperature (°C), extraction time (min), and solid to solvent ratio (g/mL) were applied as independent variables. Then, dried mangosteen seed powder extraction was carried out based on the best-operating conditions previously achieved. The DPPH scavenging activity, total phenolic content (TPC) value, and α-mangostin content of the two extracts were compared. It was discovered that the mangosteen pericarp extract showed higher antioxidant activity (IC₅₀ DPPH = 9.40 µg/mL) than the mangosteen seed extract (IC₅₀ DPPH = 37.54 µg/mL), even slightly better than ascorbic acid (IC₅₀ DPPH = 10.47 µg/mL). The best extract was produced from the bottom phase of two-phase solvent system (EtOAc:EtOH:Water 2:1:2), with an MAE temperature of 50 °C, a time of 4 min, and a solid-to-solvent ratio of 1:16. The TPC value of the best extract is 903.54 mgGAE/g extract, with a yield of 16.53 % and an α-mangostin concentration of 0.11 %.     

Obtaining Bioactive Compounds from the Coffee Husk (Coffea arabica L.) Using Different Extraction Methods

Coffee husks (Coffea arabica L.) are characterized by exhibiting secondary metabolites such as phenolic compounds, which can be used as raw material for obtaining bioactive compounds of interest in food. The objective of this study is to evaluate different methods for obtaining the raw material and extracting solutions of bioactive compounds from coffee husks. Water bath and ultrasound-assisted extraction methods were used, using water (100%) or ethanol (100%) or a mixture of both (1:1) as extracting solutions and the form of the raw material was in natura and dehydrated. The extracts were evaluated by their antioxidant potential using DPPH radicals, ABTS, and iron reduction (ferric reducing antioxidant power (FRAP)), and later total phenolic compounds, total flavonoids, and condensed tannins were quantified the phenolic majority compounds were identified. It was verified that the mixture of water and ethanol (1:1) showed better extraction capacity of the compounds with antioxidant activity and that both conventional (water bath) or unconventional (ultrasound) methods showed satisfactory results. Finally, a satisfactory amount of bioactive compounds was observed in evaluating the chemical composition (total phenolic compounds, total flavonoids, condensed tannins, as well as the analysis of the phenolic profile) of these extracts. Corroborating with the results of the antioxidant activities, the best extracting solution was generally the water and ethanol mixture (1:1) using a dehydrated husk and water bath as the best method, presenting higher levels of the bioactive compounds in question, with an emphasis on chlorogenic acid. Thus, it can be concluded that the use of coffee husk as raw material to obtain extracts of bioactive compounds is promising. Last, the conventional method (water bath) and the water and ethanol mixture (1:1) stood out among the methods and extracting solutions used for the dehydrated coffee husk.