Antioxidant activity of microwave-assisted extract of Buddleia officinalis and its major active component

Characterization of whey protein concentrate-maltodextrin-pomegranate peel phenolic compounds ternary conjugate as a novel food-grade stabilizer for nano-pickering emulsion

Developing effective food-grade stabilizers for nano-Pickering emulsions (NPEs) presents a considerable challenge, as conventional binary systems often exhibit limited functionality. The potential of ternary conjugates incorporating bioactive phenolic compounds remains underexplored. This study aimed to synthesize a novel stabilizer through covalent bonding of whey protein concentrate (WPC), maltodextrin (MD), and pomegranate peel extract (PPex) under alkaline conditions. Ultrasonication-assisted extraction (UAE), microwave-assisted extraction (MAE), and their combination (UM) were employed to extract phenolic compounds from pomegranate peel. By optimizing MAE power (300-600 W), UAE power (200 W), and extraction times (5, 10, 20 min), the highest levels of phenolic compounds (421 ± 0.13 mg Gallic acid/100 g dry peel) and antioxidant activity (90.54 ± 0.481 %) were achieved using UAE at 200 W for 30 min combined with MAE at 300 W for 5 min. Ternary conjugates were formulated with varying concentrations of PPex (0.04 %, 0.08 %, and 0.12 %). Fourier-transform infrared spectroscopy (FTIR) confirmed the interactions between WPC, MD, and PPex. NPEs prepared with ternary conjugates containing 0.12 % PPex exhibited superior stability, enhanced antioxidant activity, and reduced release of free fatty acids during in vitro digestion. Furthermore, the emulsion demonstrated a progressively organized network microstructure, contributing to improved dispersion stability. This study underscores the potential of a ternary conjugate with 0.12 % PPex to enhance NPE stability, presenting a novel approach to developing stable food-grade NPE for functional foods. Additionally, it adds value to pomegranate peel by forming natural protein-polysaccharide- phenolic compounds complex particles.

Pharmacological in vitro profiling of Buddleja officinalis flower extracts in the context of dry eye disease

BACKGROUND

Dry eye disease (DED) is caused by inflammation on the ocular surface and insufficient quality or production of the tear film. Due to various harmful environmental conditions, a gradual increase of DED cases has been reported.

HYPOTHESIS/PURPOSE

This study aims for a comprehensive in vitro pharmacological and phytochemical profiling of two different Buddleja officinalis Maxim. extracts to assess their potential for the treatment of DED.

METHODS

A hydroethanolic (BO-HE) and a lead-like enhanced (BO-LLE) B. officinalis extract were phytochemically characterized by UHPLC-UV-MS and UHPLC-ELSD analyses. Afterwards, the effects of either BO-HE or BO-LLE on in vitro dry eye models, including human corneal epithelial cell-transformed (HCE-T) cells, immortalized human meibomian gland epithelial cells (IHMGECs) and human leukemia monocytic (THP-1) cells, and Jurkat cells, were investigated.

RESULTS

Both extracts exhibited strong anti-inflammatory properties with free radical scavenging activities and reduction of intracellular reactive oxygen species (ROS) in UVB-exposed HCE-T cells. Treatment with BO-HE or BO-LLE showed wound healing capacities. Moreover, both extracts differentially modulate mediator secretion in UVB-exposed HCE-T cells. In IHMGECs, the size of secreted lipid droplets was larger in BO-LLE treated cells. As for immune cells, a significant reduction in levels of TNF-α and IL-6 secretion by lipopolysaccharide (LPS)-exposed THP-1 cells was observed. Additionally, BO-LLE effectively inhibited intracellular calcium influx in Jurkat cells even at low concentrations.

CONCLUSION

The results of this study demonstrate pharmacological potential of B. officinalis flowers for the treatment of DED pathology with BO-LLE exerting a slightly more beneficial profile than BO-HE.

Identification of a novel oligopeptide from defatted walnut meal hydrolysate as a potential neuroprotective agent

Free radical damage and oxidative stress are thought to play a crucial role in the development of neurodegenerative diseases. Walnut peptides, especially walnut oligopeptides, have been shown to protect nerve cells from oxidative stress and inflammatory damage, as well as improve memory function. In this study, walnut peptides were obtained from walnut meal through enzymatic hydrolysis, ultrafiltration, and gel filtration chromatography. A novel oligopeptide called AQ was successfully isolated and its chemical structure was identified as AASCDQ using ESI-MS/MS. AQ demonstrated remarkable scavenging activity against O2- free radicals (81.00%), DPPH free radicals (79.40%), and ABTS free radicals (67.09%) at a concentration of 1 mg mL-1. Furthermore, AQ exhibited strong neuroprotective effects against hydrogen peroxide-induced damage in SH-SY5Y cells, reducing cell injury and apoptosis. AQ also effectively inhibited the secretion of pro-inflammatory factors NO (IC50 = 46.03 ± 0.32 μM) and suppressed the expression of IL-6 and TNF-α in RAW264.7 cells stimulated by LPS. In vivo experiments demonstrated that AQ promoted angiogenesis in the quail chick chorioallantoic membrane assay and reduced ROS accumulation in Caenorhabditis elegans, thereby extending its lifespan. The anti-inflammatory mechanism of AQ was further confirmed by western blotting. In summary, the novel oligopeptide AQ possesses potential neuroprotective effects, including antioxidant, anti-inflammatory, angiogenic, and anti-aging properties, making it a promising candidate for the development of functional foods and pharmaceutical products.

Antioxidant and anti-inflammatory polyphenols in ultrasound-assisted extracts from salvilla (Buddleja scordioides Kunth)

Salvilla is a widely distributed plant used in treatments against gastrointestinal disorders due to its phenolic antioxidant and anti-inflammatory potential. Major yield and quality of bioactive polyphenols must be obtained with no degradation during suitable processes such as Ultrasound-Assisted Extraction (UAE), which allows an efficient extraction of metabolites at appropriate parameter conditions. Salvilla extractions were made using UAE and aqueous ethanolic solutions. Variables used in UAE were sonication time, wave amplitude and percentage of ethanol in solvent. Extracts were tested for total flavonoids, antioxidant activity (ABTS, FRAP and ORAC) and an identification and quantification of phenolic compounds was carried out by UPLC-PDA-ESI-MS/MS. Once elected the better extraction conditions, an anti-inflammatory test was performed for this treatment. As a result, total flavonoids content in extracts was 147 to 288 µg catechin equivalents/mg of dry salvilla extract. All extracts have shown good antioxidant activity (86 to 280 mM Trolox eq/mg dry salvilla extract). Flavonoids contents by chromatography were higher than hydroxybenzoic and hydroxycinnamic acids specially the flavone, flavanol and flavanone groups. Treatment T6 (75% ethanol, 30% amplitude and 10 min extraction time) was the best extract in terms of significant flavonols, antioxidant activity, and higher anti-inflammatory potential.

Anti-inflammatory and antioxidant activities of chemical constituents from the flower buds of Buddleja officinalis

Five new glycosides including mimenghuasu A and B (1-2), isolinarin (3), cyclocitralosides A and B (4-5), along with forty-seven known compounds were isolated from the flower buds of Buddleja officinalis. These structures were elucidated by extensive spectroscopic analysis (UV, IR, 1 D, 2 D NMR, and MS spectra). The anti-inflammatory activities of the isolated compounds were determined by enzyme-linked immunosorbent assay (ELISA) on the expression of TNF-α (LPS-activated RAW264.7 cells) and MTT experiment on LPS-induced HUVECs proliferation effects. Good suppressive effects on the expression of TNF-α were shown by 4 and 5 with IC₅₀ values of 19.35 and 22.10 μM, respectively, compared to positive control indomethacin (IC₅₀ 16.40 μM). In addition to this, some isolated compounds exhibited excellent antioxidant activities including compounds 16, 18, 29, 39, and 47 (IC₅₀ μM: 82.59, 72.94, 33.65, 46.67, and 20.81, respectively) with almost the same or stronger potency with reference to vitamin C as positive control (IC₅₀ 81.83 μM).

Conventional and Emerging Extraction Processes of Flavonoids

Flavonoids are a group of plant constituents called phenolic compounds and correspond to the nonenergy part of the human diet. Flavonoids are found in vegetables, seeds, fruits, and beverages such as wine and beer. Over 7000 flavonoids have been identified and they have been considered substances with a beneficial action on human health, particularly of multiple positive effects because of their antioxidant and free radical scavenging action. Although several studies indicate that some flavonoids have provident actions, they occur only at high doses, confirming in most investigations the existence of anti-inflammatory effects, antiviral or anti-allergic, and their protective role against cardiovascular disease, cancer, and various pathologies. Flavonoids are generally removed by chemical methods using solvents and traditional processes, which besides being expensive, involve long periods of time and affect the bioactivity of such compounds. Recently, efforts to develop biotechnological strategies to reduce or eliminate the use of toxic solvents have been reported, reducing processing time and maintaining the bioactivity of the compounds. In this paper, we review, analyze, and discuss methodologies for biotechnological recovery/extraction of flavonoids from agro-industrial residues, describing the advances and challenges in the topic.

Conventional method and microwave drying kinetics of Laurus nobilis leaves: effects on phenolic compounds and antioxidant activity

Abstract Laurus nobilis constitutes one of the usually studied Mediterranean trees due to its therapeutic effects, nutritional properties, and ornamental use. In the current investigation, a comparative study was conducted between two types of drying methods, a microwave-assisted drying (MWD) (from 180 to 900 W) and a conventional method (open-air and oven-drying using temperatures from 40 °C to 120 °C). Drying kinetics were carried out as a function of moisture content according to time. Total Phenolic Content (TPC) as well as reducing power of obtained products were determined. Kinetic results showed that the time required for dried bay leaves became shorter as temperature and microwave power increased; drying with the microwave was much more efficient than conventional methods (open-air and oven-drying). Antioxidants of the Laurus nobilis leaves were better conserved using open-air and microwave drying. Our results underlined a significant correlation between TPC and reducing power. Microwave drying using 300 W during 130 s was the most efficient combination that provided dried bay leaves with the highest content of phenolic compounds and antioxidant activity.

Polyphenol Content, Physicochemical Properties, Enzymatic Activity, Anthocyanin Profiles, and Antioxidant Capacity ofCerasus humilis(Bge.) Sok. Genotypes

Seven varieties of Chinese dwarf cherries were evaluated and compared with respect to their weight, diameter, titratable acidity, total soluble solids, color, polyphenol contents, ascorbic acid levels, anthocyanin profiles, enzymatic activity, and antioxidant capacity. The fruits are rich in phenolic content (339.07–770.30 mg/100 g fresh weight). Nine anthocyanins were obtained from fruits after chromatographic separation and their structures analyzed using HPLC-ESI-MS/MS. Cyanidin-3-glucoside was the major anthocyanin with 50.36–78.39% concentration. Three anthocyanins were reported for the first time in these cherries. They exhibit low polyphenol oxidase and peroxidase activities, but their superoxide dismutase activity is high (572.75–800.17 U/g FW). The highest amounts of soluble solid content (15.67 Brix %), total titratable acid (1.90%), ascorbic acid (18.47 mg/100 g FW), and total anthocyanin (152.66 mg/100 g FW) were observed. Three methods (DPPH-scavenging ability, oxygen radical absorbance capacity assay, and cellular antioxidant activity assay) were employed to evaluate the antioxidant capacity of the phenolic extracts of these cherries. Number 5 has the highest values of ORAC and CAA of 205.68 μmol TE/g DM and 99.67 μmol QE/100 g FW, respectively.

Effects of Black Pepper (Piper nigrum L.) Chloroform Extract on the Enzymatic Activity and Metabolism of Escherichia coli and Staphylococcus aureus

The chemical composition and antimicrobial mechanism of action of black pepper chloroform extract (BPCE) were investigated, as well as the potential antibacterial activities of BPCE against Escherichia coli and Staphylococcus aureus. The results showed that 1H-Cycloprop[e]azulen-7-ol, decahydro-1,1,7-trimethyl-4-methylene-, [1ar-(1aα,4aα,7β,7a,β,7bα.)]- (8.39%) and 2-methylene-4,8,8-trimethyl-4-vinyl-bicyclo[5.2.0]nonane (6.92%) were identified as the two primary components of BPCE. The release of intracellular transaminases from bacteria after being incubated with BPCE revealed that the bacterial cell walls and membranes were degraded and that protein synthesis was inhibited to some extent. The inhibition of bacterial Na+/K+-ATPase activity upon the addition of BPCE also indicated an enhanced permeability of bacterial cell membranes. Moreover, an analysis of hexokinase and pyruvate kinase activities showed that BPCE affected the metabolic rate of glycolysis and disrupted the normal metabolism of bacteria. This phenomenon was supported by an observed accumulation of lactic acid (LA) in the treated bacterial cells. Overall, our results indicated that BPCE damaged bacterial cell walls and membranes, which was followed by a disruption of bacterial cell respiration.

Phytochemical analysis of Myrtus communis plant: Conventional versus microwave assisted-extraction procedures

Background

Myrtle (

Methods

Extraction yield/efficiency and antioxidant activity were measured using radical scavenging assay (DPPH

Results

The results show that the MAE was higher in terms of saving energy, extraction time (62 s) and extraction efficiency of bioactive compound compared to CME (2 h). Leaf presented the optimum content of total phenols (250 mg GAE.g

Conclusions

Principal component analysis (PCA) applied to the experimental data shows that the distribution of the myrtle phenolic compounds depended on their plant part localization as well as the extraction method.

Phytochemicals in Capsicum oleoresin from different varieties of hot chilli peppers with their antidiabetic and antioxidant activities due to some phenolic compounds

Due to its wide use in nutritional therapy, a capsicum oleoresin extraction from hot chilli pepper was optimized using ultrasound assisted extraction. Under optimal conditions, a 0.1g sample in 10mL of a 20% water in methanol solution was extracted at 50°C for 20min to remove phytochemicals consisting of oleoresin, phenolics, carotenoids, flavonoids, capsaicinoids (pungency level), reducing sugars. Antioxidant and antidiabetic activities of the crude extracts from 14 chilli pepper varieties were examined. The antioxidant and antidiabetic activities of some phenolic compounds were also tested individually. The results showed that these chilli pepper samples are a rich source of phytochemicals with antioxidant and antidiabetic activities. High antioxidant activity of the extracts was evaluated using the 2,2-diphenyl-1-picrylhydrazyl, N,N-dimethyl-p-phenylenediamine dihydrochloride, 2,2'-azino-bis(3-ethylbenzothiazolin-6-sulfonic acid) and ferric ion reducing antioxidant power assays. The crude extracts had a lower level of sugars induced by the inhibitory effect of α-amylase activity. Thus, their enzymatic inhibitory effect might have resulted from a synergism among the phytochemicals concerned. Therefore, a diet with this type of food may have beneficial health effects.

Antimicrobial and Antioxidant Activities of the Extract and Fractions of Tetradenia riparia (Hochst.) Codd (Lamiaceae) Leaves from Brazil

Tetradenia riparia (Lamiaceae) is native to Central Africa popularly known as myrrh, used in folk medicine to treat various diseases like malaria, gastroenteritis, and tropical skin disease. This research was to evaluate the antioxidant and antibacterial activities of the crude extract (CE) and fractions (FR) of the T. riparia by classical chromatography. The CE of T. riparia leaves was submitted to column chromatographic fractionation to obtain four fractions of the interest, which were identified by nuclear magnetic resonance and gas chromatograph coupled to mass spectrum: FR-I (abieta-7,9(11)-dien-13-β-ol), FR-II (Ibozol), FR-III (8 (14), 15-sandaracopimaradiene-2α, 18-diol and 8 (14), 15-sandaracopimaradiene-7α, 18-diol), and FR-IV (Astragalin, Boronolide and Luteolin). Total phenol content of CE and FR were measured, and antioxidant action by methods of DPPH (2,2-diphenyl-1-picrylhydrazyl), β-carotene/linoleic acid system, and ferric reducing/antioxidant power (FRAP) and the antibacterial activity was evaluated by the broth microdilution method with the determination of the minimum inhibitory concentration (MIC). The FR-IV presented antioxidant potential with 181.67 μg gallic acid/mg, IC₅₀ of 0.61 μg/mL by DPPH method, 55.61% oxidation protection by β-carotene/linoleic acid system and 4.59 µM ferrous sulfate/mg of sample by FRAP, and the FR-I showed higher antibacterial potential on the strain Staphylococcus aureus with MIC 0.98 μg/mL, Enterococcus faecalis and Bacillus cereus with MIC 31.2 μg/mL. Thus, the fractionation of CE was extremely important to detect fractions with potential activities, and investigations are necessary regarding the mechanism of action and action in vivo.

Polysaccharides from Traditional Chinese Medicines: Extraction, Purification, Modification, and Biological Activity

Traditional Chinese Medicine (TCM) has been used to treat diseases in China for thousands of years. TCM compositions are complex, using as their various sources plants, animals, fungi, and minerals. Polysaccharides are one of the active and important ingredients of TCMs. Polysaccharides from TCMs exhibit a wide range of biological activities in terms of immunity- modifying, antiviral, anti-inflammatory, anti-oxidative, and anti-tumor properties. With their widespread biological activities, polysaccharides consistently attract scientist's interests, and the studies often concentrate on the extraction, purification, and biological activity of TCM polysaccharides. Currently, numerous studies have shown that the modification of polysaccharides can heighten or change the biological activities, which is a new angle of polysaccharide research. This review highlights the current knowledge of TCM polysaccharides, including their extraction, purification, modification, and biological activity, which will hopefully provide profound insights facilitating further research and development.

Effects of pretreatments on anthocyanin composition, phenolics contents and antioxidant capacities during fermentation of hawthorn (Crataegus pinnatifida) drink

The effect of microwave and heat pretreatment on the content and composition of anthocyanins, phenolics, and the antioxidant capacity of hawthorn drink were studied. Nine anthocyanins were isolated by chromatographic separation from the Zirou hawthorn source and their structure identified using HPLC-DAD-ESI/MS analysis. Heat and microwave pretreatments had a significant impact on the relative contents of hawthorn anthocyanins, such as cyanidin-3-galactoside (82.9% and 76.9%, respectively) and cyanidin-3-glucoside (9.2% and 11.5%, respectively). Pretreatment had no significant effect on pH, total soluble solid or total acid. More anthocyanins remained after heat treatment than after microwaving (0.745mg/100mL), and were 52.4% higher than the control group after storage for 7days. The colour density of the heat treated group was higher than the control group (24.5%) after 12days of fermentation. The main antioxidant capacities of the hawthorn drinks came from total polyphenolics rather than total anthocyanins or total flavonoids.

Antibacterial and Antioxidant Activities of Essential Oils from Artemisia herba-alba Asso., Pelargonium capitatum × radens and Laurus nobilis L

Essential oils are natural antimicrobials that have the potential to provide a safer alternative to synthetic antimicrobials currently used in the food industry. Therefore, the aim of this study was to evaluate the antimicrobial and antioxidant activities of essential oils from white wormwood, rose-scented geranium and bay laurel against Salmonella typhimurium and Escherichia coli O157:H7 on fresh produce and to examine consumer acceptability of fresh produce treated with these essential oils. Our results showed that essential oil derived from rose-scented geranium exhibited the most effective antimicrobial activity at the same and similar minimum inhibition concentration levels (0.4%, v/v and 0.4% and 0.5%, v/v) respectively against Salmonella typhimurium and Escherichia coli O157:H7. All three essential oils showed antioxidant properties, with the highest activity occurring in bay laurel essential oil. In a sensory test, tomatoes, cantaloupe and spinach sprayed with 0.4% rose-scented geranium essential oil received higher scores by panelists. In conclusion, rose-scented geranium essential oil could be developed into a natural antimicrobial to prevent contamination of Salmonella typhimurium and Escherichia coli O157:H7 in fresh produce, plus this oil would provide additional health benefits due to the antioxidant properties of its residue.

Can consumption of antioxidant rich mushrooms extend longevity?: antioxidant activity of Pleurotus spp. and its effects on Mexican fruit flies' (Anastrepha ludens) longevity

The variability of antioxidant capacity of 14 strains of the edible oyster mushroom Pleurotus spp. was determined, and the effect of selected mushroom supplements on the longevity of the Mexican fruit fly, Anastrepha ludens, was evaluated. The antioxidant capacity of the fruiting bodies was determined by three different methods, measuring the free radical scavenging activity of methanolic extracts, the OH radical scavenging capacity, and the total phenol content. The inhibition percentage of the DPPH radical varied between 32.6 and 85.7% and total phenols varied between 30.6 and 143.3 mg/g. The strains with the highest (Pleurotus djamor ECS-0142) and lowest (Pleurotus ostreatus ECS-1123) antioxidant capacity were selected to study their effect on the survival, life expectancy, and mortality of the Mexican fruit fly A. ludens. The results demonstrated differing responses between male and female flies. High concentrations of mushrooms (5 and 20%) in the diet resulted in a decrease in life expectancy. However, flies on the diet with 1% P. djamor ECS-0142 showed slightly but significantly greater survival than those on the control diet. The possible adverse effect of protein content in mushroom extracts is discussed.

Evaluation of antioxidant-associated efficacy of flavonoid extracts from a traditional Chinese medicine Hua Ju Hong (peels of Citrus grandis (L.) Osbeck)

ETHNOPHARMACOLOGICAL RELEVANCE

Hua Ju Hong (HJH, peels of Citrus grandis (L.) Osbeck) is a popularly used traditional Chinese medicine recorded by "Compendium of Materia Medica" (Ben Cao Gang Mu) in Ming Dynasty of China (1578 A.D.). With flavonoid components, HJH possesses hypolipidemic effect associated with antioxidation action. However, no report was found regarding the flavonoid profile and antioxidant activity of HJH.

MATERIALS AND METHODS

Five purified flavonoid extracts (TFCA, TFCB, TFCC, TFCD and TFCE.) were obtained from HJH using Ca(OH)2 and HPD-300 macroporous resins, and their total flavonoids and representative flavonoid components were analyzed. In vitro tests of DPPH free radical scavenging activity, reducing power, and total antioxidant activity of each extract were evaluated. The most effective extract was selected for in vivo antioxidative evaluation using a rat hyperlipemia model.

RESULTS

The total flavonoid content was varying among each HJH extract and decreased in an order of TFCB>TFCD>TFCC>TFCE>TFCA. TFCB, TFCD, and TFCC contained more than 50% of total flavonoids, the highest content of which was found in TFCB (80.7%). HPLC analysis showed that the contents of three flavonoid components, narirutin, naringin and neohesperidin, displayed a similar trend as that of total flavonoids. In vitro antioxidative tests determined that TFCB at 0.24 to 1.2mg/ml possessed the most significant antioxidant effects among other extracts and was also superior to BHT. In vivo experiment also revealed the significant antioxidant and antihyperlipidemic activities of TFCB started from 50 to 200mg/kg after oral administration to hyperlipemia rats. These results indicate that TFCB with the highest flavonoid contents has the strongest antioxidant-associated activities.

CONCLUSION

This is the first report regarding antioxidant-associated activities and relevant flavonoid components of HJH extracts, providing a promising candidate of traditional Chinese medicine for antioxidative treatment.

Photoprotection of Buddleja cordata extract against UVB-induced skin damage in SKH-1 hairless mice

Background

In recent years, there has been considerable interest in using botanical agents to prevent skin damage resulting from solar UV-irradiation. Buddleja cordata is a plant that is known as “tepozan”. Some people in Mexico use the leaves of this plant to treat tumours, abscesses, sores and burns. The purpose of this study is to investigate the photoprotective properties of Buddleja cordata methanolic extract (BCME) against UVB-induced skin damage in SKH-1 hairless mice at the macroscopic and histological levels.

Methods

BCME was characterised to determine its spectroscopic, chromatographic and antioxidant (DPPH, superoxide and hydroxyl radicals) properties. To conduct the photoprotection studies, BCME was applied topically to the skin of SKH-1 mice before acute exposure to UVB for 10 minutes. The murine skin samples were used for macroscopic and histological studies to assess tissue damage. Penetration of active components of BCME into stratum corneum on the dorsal area of mice was investigated in vivo by the tape stripping method. Moreover, genotoxicity of BCME was evaluated in a Vicia faba cell root micronucleus model.

Results

BCME displayed absorbance over the entire UVB spectrum, and its principal components included verbascoside and linarin. BCME exhibited antioxidant activity and significantly scavenged hydroxyl radicals. BCME reduced erythema, sunburn cell production, vessel congestion and epidermal thickening of UVB irradiated mouse skin. BCME penetrate the skin of mice. BCME did not exhibit genotoxic activity in the micronucleus test.

Conclusion

The topical administration of BCME protected against acute UVB-induced damage in mouse SKH-1 skin, and our results suggest that BCME may potentially prevent photodamage.

Optimization of microwave-assisted extraction of polyphenols from Myrtus communis L. leaves

Phytochemicals, such as phenolic compounds, are of great interest due to their health-benefitting antioxidant properties and possible protection against inflammation, cardiovascular diseases and certain types of cancer. Maximum retention of these phytochemicals during extraction requires optimised process parameter conditions. A microwave-assisted extraction (MAE) method was investigated for extraction of total phenolics from Myrtus communis leaves. The total phenolic capacity (TPC) of leaf extracts at optimised MAE conditions was compared with ultrasound-assisted extraction (UAE) and conventional solvent extraction (CSE). The influence of extraction parameters including ethanol concentration, microwave power, irradiation time and solvent-to-solid ratio on the extraction of TPC was modeled by using a second-order regression equation. The optimal MAE conditions were 42% ethanol concentration, 500 W microwave power, 62 s irradiation time and 32 mL/g solvent to material ratio. Ethanol concentration and liquid-to-solid ratio were the significant parameters for the extraction process (p<0.01). Under the MAE optimised conditions, the recovery of TPC was 162.49 ± 16.95 mg gallic acidequivalent/gdry weight(DW), approximating the predicted content (166.13 mg GAE/g DW). When bioactive phytochemicals extracted from Myrtus leaves using MAE compared with UAE and CSE, it was also observed that tannins (32.65 ± 0.01 mg/g), total flavonoids (5.02 ± 0.05 mg QE/g) and antioxidant activities (38.20 ± 1.08 μg GAE/mL) in MAE extracts were higher than the other two extracts. These findings further illustrate that extraction of bioactive phytochemicals from plant materials using MAE method consumes less extraction solvent and saves time.

Effect of methionine on production of naphthoquinones in Impatiens balsamina root cultures and detection of some secondary metabolites

CONTEXT

Lawsone, lawsone methyl ether and 3,3'-methylelnebislawsone are the main active compounds of Impatiens balsamina L. (Balsaminaceae). These compounds possess various pharmacological activities that have been shown to assist with the treatment of skin diseases.

OBJECTIVE

This work focused on increased naphthoquinone production in I. basamina root cultures using methionine feeding.

MATERIALS AND METHODS

I. balsamina root cultures were maintained in liquid Gamborg's B5 medium supplemented with 0.1 mg/L α-naphthalene acetic acid, 0.1 mg/L kinetin, 1.0 mg/L 6-benzyladenine and 20 g/L sucrose. The effect of methionine concentration (50, 100, 300, 500 and 1000 mg/L) on naphthoquinone production of I. basamina root cultures was determined. Isolation of secondary metabolites from I. balsamina root cultures was also carried out.

RESULTS AND DISCUSSION

Feeding of 300 mg/L methionine to the root cultures at the beginning of the growth cycle increased the production of 3,3'-methylelnebislawsone almost two-fold (0.63 mg/g dry weight, compared to the control group 0.32 mg/g dry weight). Optimization of the feeding conditions showed that adding 500 mg/L methionine to a 21-day old root cultures increased production of lawsone methyl ether and 3,3'-methylenebislawsone up to 2.6- and 3.1-fold higher, respectively, compared to the controls. In addition, various pharmacologically interesting secondary metabolites were isolated from I. balsamina root cultures, such as a flavonoid, luteolin, a naphthoquinone, 2,3-dihydroxy-1,4-naphthoquinone, and a triterpenoid, echinocystic acid. This is the first report of the occurrence of these compounds in this plant.

Variations of antioxidant characteristics and mineral contents in pulp and peel of different apple (Malus domestica Borkh.) cultivars from Pakistan

Variations of phenolics, antioxidant activity, and mineral contents in peel and pulp of five apple (Malus domestica Borkh.) cultivars from Pakistan, namely Red Delicious, Golden Delicious, Kashmiri Amri, Kala Kulu and Sky Spur were appraised. The mean extract yield of antioxidant components obtained with 80:20 methanol-water (v/v), was found to be 22.1 g/100 g for peel and 14.2 g/100 g for pulp on a dry weight basis. The amounts of total phenolics and total flavonoids in peel and pulp of different cultivars of apple ranged from 1,907.5-2,587.9 mg gallic acid equivalent/100 g DW and 1,214.3-1,816.4 mg catechin equivalent/100 g DW and 1,185.2-1,475.5 mg GAE/100 g DW and 711.8-999.3 mg CE/100 g DW, respectively. The inhibition of linoleic acid peroxidation and DPPH scavenging activity of the extracts varied from 71.7-84.9 and 66.6-80.8% in peel, and 43.9-52.8 and 42.9-51.1% in pulp, respectively. Reducing power of the tested fruit part extracts at concentration 12.5 mg/mL ranged from 2.54-2.89 and 1.37-1.73, respectively. With regard to minerals analysis, both fruit parts showed the amount of K to be the highest, followed by Mg, Ca, Fe, Na and Zn. The results revealed that peel of the tested apple cultivars in this study had superior antioxidant capacity and mineral concentration than the pulp, indicating significant variations between the parts tested. Thus, consumption of apple fruits along with peel might be recommended to gaining better nutritive benefits.