Extraction and quantification of polyphenols from kinnow (Citrus reticulate L.) peel using ultrasound and maceration techniques

An investigation was carried out to extract polyphenols from the peel of kinnow (Citrus reticulate L.) by maceration and ultrasound-assisted extraction (UAE) techniques. The antioxidant potential of these polyphenols was evaluated using ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and superoxide radical scavenging assays; and their antimicrobial activity was assessed against bacterial strains Staphyloccoccus aureus, Bacillus cereus, and Salmonella typhimurium. The highest extraction yield was obtained through the solvent ethanol at 80% concentration level, whereas UAE was a more efficient technique and yielded comparatively higher polyphenol contents than maceration. Maximum polyphenols were extracted with 80% methanol [32.48 mg gallic acid equivalent (GAE)/g extract] using UAE, whereas minimum phenolics (8.64 mg GAE/g extract) were obtained with 80% ethyl acetate through the maceration technique. Elevated antioxidant activity of kinnow peel extracts was exhibited in three antioxidant assays, where 80% methanolic extracts showed the highest antioxidant activity (27.67 ± 1.11mM/100 g for FRAP) and the highest scavenging activity, 72.83 ± 0.65% and 64.80 ± 0.91% for DPPH and superoxide anion radical assays, respectively. Strong correlations between total polyphenols and antioxidant activity were recorded. Eleven phenolic compounds—including five phenolic acids and six flavonoids—were identified and quantified by high performance liquid chromatography. Ferulic acid and hesperidin were the most abundant compounds whereas caffeic acid was the least abundant phenolic compound in kinnow peel extracts. Maximum inhibition zone was recorded against S. aureus (16.00 ± 0.58 mm) whereas minimum inhibition zone was noted against S. typhimurium (9.00 ± 1.16 mm). It was concluded that kinnow mandarin peels, being a potential source of phenolic compounds with antioxidant and antimicrobial properties, may be used as an ingredient for the preparation of functional foods.     

Choline chloride-based deep eutectic solvents do not improve the ethanolic extraction of carotenoids from buriti fruit (Mauritia flexuosa L.)

The aim of the present study was to evaluate the effect of choline chloride-based deep eutectic solvents (DESs) as co-solvents for the ethanolic extraction of total carotenoids from buriti fruit (Mauritia flexuosa L.). Choline chloride-based DESs were synthesized by the heating method. The systems were prepared using ethanol and DESs as a co-solvent in concentrations of 0.5–70.0% (w/v). In addition, a control condition was performed using ethanol as the sole solvent. The total carotenoid concentration in the systems was determined by spectrophotometry at 450 nm. The results showed that the ethanol used without co-solvent obtained total carotenoid yields of 10.06 ± 0.03 mg/g for the buriti pulp and 10.43 ± 1.27 mg/g for the buriti peel. In turn, the use of choline chloride-based DESs as co-solvents did not increase the ethanolic extraction yield of carotenoids. However, it was observed that the buriti peel can be a rich source of carotenoids with yields comparable to the fruit. Thus, it is suggested that new green solvents be evaluated to increase the recovery of total carotenoids from buriti fruit using ecofriendly processes.     

Comparative analysis of the antioxidant and DNA protection capacities of Anadenanthera colubrina, Libidibia ferrea and Pityrocarpa moniliformis fruits

This study aimed to explore the antioxidant and DNA protection abilities of hydroalcoholic extracts from fruits of Anadenanthera colubrina (ACHE), Libidibia ferrea (LFHE) and Pityrocarpa moniliformis (PMHE). These extracts were tested by five antioxidant methods (phosphomolibdenium and reducing power assays; superoxide, hydrogen peroxide and nitric oxide scavenging) and DNA protection capacity. Total phenolic content was measured by Folin-Ciocalteu method. ACHE exhibited the highest phenolic content (578 mg/g GAE), followed by LFHE (460 mg/g GAE) and PMHE (448 mg/g GAE). In phosphomolibdenium assay, ACHE showed 24.81% of activity in relation to ascorbic acid, whereas LFHE and PMHE had 21.08% and 18.05%, respectively. These plants showed high ability to inhibit reactive species tested with IC50 values ranged from 10.66 to 14.37 μg/mL for superoxide radical; 26.05 to 45.43 μg/mL for hydrogen peroxide; 178.42 to 182.98 μg/mL for reducing power; and 199.2 to 283 μg/mL for nitric oxide. Furthermore, these extracts had capacity to break the DNA damage induced by hydroxyl radicals. The antioxidant activity of these plants is related with their higher phenolic content and show that they may be used as source of bioactive compounds, relevant to the maintenance of oxidative stability of the food matrix, cosmetics and/or pharmaceutical preparations.     

Flavonoid compositions and antioxidant activity of calamondin extracts prepared using different solvents

Calamondin has been demonstrated to exhibit antioxidant function and tyrosinase inhibitory activity, which might be attributed to its flavonoid compounds. To improve their application, the flavonoid compositions and antioxidant activity of calamondin extracts, prepared by different solvents, were investigated. The results showed that total phenolic and flavonoid contents of extracts from peel of calamondin were higher than that from pulp, except the flavonoid content in hot water extract. The flavonoids found in extracts of calamondin were 3′,5′-di-C-β-glucopyranosylphloretin (DGPP), naringin, hesperidin, nobiletin, tangeretin, and diosmin. DGPP exhibited the highest quantity, while naringin and hesperidin were the other two major flavonoids. The content of DGPP in hot water extract of peel was higher than in extracts of organic solvents, however, the contents of nobiletin and tangeretin were found only in extracts of organic solvents. The highest levels of total flavonoids and DGPP were obtained in hot water extract from peel at 90°C. The extracts of hot water and ethyl acetate showed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging potency than that of ethanol and methanol. A positive relationship existed between total phenolic contents and DPPH scavenging potency (p < 0.01), while total flavonoid compositions also showed correlation (p < 0.05). Thus, DGPP, naringin, and hesperidin might contribute to antioxidant activity. Collectively, the hot water extract of calamondin peel might have potential for health food and cosmetic applications due to its good antioxidant activity and high level of DGPP.     

Juniperus oxycedrus L. subsp. oxycedrus and Juniperus oxycedrus L. subsp. macrocarpa (Sibth. & Sm.) Ball. “berries” from Turkey: Comparative evaluation of phenolic profile,antioxidant, cytotoxic and antimicrobial activities

This work aimed to evaluate and compare the phenolic profile and some biological properties of the ripe “berries” methanol extracts of Juniperus oxycedrus L. subsp. oxycedrus (Joo) and Juniperus oxycedrus L. subsp. macrocarpa (Sibth. & Sm.) Ball. (Jom) from Turkey. The total phenolic content resulted about 3-fold higher in Jom (17.89 ± 0.23 mg GAE/g extract) than in Joo (5.14 ± 0.06 mg GAE/g extract). The HPLC–DAD–ESI–MS analysis revealed a similar flavonoid fingerprint in Joo and Jom, whereas a difference in their quantitative content was found (4632 μg/g extract and 12644 μg/g extract). In addition, three phenolic acids were detected in Jom only (5765 μg/g extract), and protocatechuic acid was the most abundant one. The antioxidant capacity of the extracts was evaluated by different in vitro assays: in the DPPH and in the TBA tests a stronger activity in Jom was highlighted, while Joo exhibited higher reducing power and metal chelating activity. Joo and Jom did not affect HepG2 cell viability and both extracts resulted virtually non-toxic against Artemia salina. The extracts were also studied for their antimicrobial potential, displaying efficacy against Gram-positive bacteria.     

Malt and beer-related by-products as potential antioxidant skin-lightening agents for cosmetics

Malt and beer-related by-products, namely caramalt, aromatic malt, roasted malt, malt sprouts, dark beer spent grains, and wheat beer spent grains were extracted with water under moderate conditions to exploit the potential as sources of bioactive compounds. After characterizing the extracts in terms of carbohydrate, amino acid, and phenolic contents and composition, their antioxidant potential was assessed in vitro using keratinocyte cell cultures. Malt sprouts provided highest yields of glucose (50.1 mg g^-1) and fructose (38.4 mg g^-1), while the other materials gave up to 13.5 mg g^-1. Furthermore, malt sprouts gave a total amino acid content of 57.6 mg g^-1. Extracts of darker malts such as caramalt and roasted malt exhibited the highest yields of phenolic compounds of about 12.9 mg gallic acid equivalents (GAE) g^-1 and extracts from spent grains had the lowest total yield with 5.1 and 1.8 mg GAE g^-1 (dark beer and wheat beer spent grains), respectively. Phenolic compounds in caramalt extract inhibited the tyrosinase activity by 78% and 87%, when applying extract concentrations of 0.5% and 1%, respectively. Dark malt, roasted malt as well as the malt sprouts extracts achieved similar effects of 86% and 80% inhibition, when using a 1% extract. In contrast, extracts of spent grains showed low inhibitory effects. This study indicates the potential of malt and beer-related by-products as biological sources of ingredients for cosmeceutical products, for instance, in skin whitening.     

Bioactive microconstituents and antioxidant properties of wild edible mushrooms from the island of Lesvos,Greece

Crude composition, fatty acids, sterols, total phenolic content (TPC), individual polyphenols and terpenic acids were determined in five wild edible mushrooms species (Lactarius deliciosus, Lactarius sanguifluus, Lactarius semisanguifluus, Russula delica, Suillus bellinii) from Lesvos Island, Greece. In addition, the DPPH scavenging capacity, the ferric ion reducing power (FRAP) and the ferrous ion chelating activity of mushroom methanolic extracts were assessed. Among sterols, ergosterol predominated at concentrations 9.2–18.0 mg/100 g fw. Total phenolic content of mushroom extracts ranged from 6.0 to 20.8 mg GAE/100 g fw. Up to 19 simple polyphenols were determined in mushrooms extracts, the more abundant being p-OH-benzoic acid, p-OH-phenylacetic acid, o-coumaric acid, ferulic acid and chrysin. In addition, the triterpenic acids oleanolic and ursolic were detected for the first time in mushrooms. All species exerted antioxidant activity and ferrous ion chelating capacity. Principal component analysis revealed good correlations between TPC, DPPH and FRAP but not with metal chelating activity. It seems that mushrooms polyphenols exert antiradical and reducing activities, but they are not strong metal chelators, the observed chelating ability being probably due to other classes of compounds.To our knowledge, this is the first report on the bioactive microconstituents and antioxidant activity of wild Greek edible mushrooms.     

Antioxidant capacity and bioactive compounds of four Brazilian native fruits

The purpose of this study was to evaluate the bioactive compounds and antioxidant activity of extracts from araçá (Psidium cattleianum), butiá (Butia eriospatha), and pitanga (Eugenia uniflora) fruits with different flesh colors (i.e., purple, red, and orange), and blackberries (Rubus sp.; cv. Xavante and Cherokee) collected in the southern region of Brazil. The content of ascorbic acid, total carotenoids, and phenolics were determined. The profile of the phenolic compounds was assessed by high-performance liquid chromatography combined with diode array detection (HPLC-DAD). The antioxidant activity was determined using the ferric-reducing antioxidant power (FRAP) assay, 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) assay, total reactive antioxidant potential (TRAP) assay, and total antioxidant reactivity (TAR) assay. The Xavante blackberry and purple-fleshed pitanga showed the highest total phenolic content [816.50 mg gallic acid equivalents (GAE)/100g and 799.80 mg GAE/100g, respectively]. The araçá and red-fleshed pitanga showed the highest carotenoid content (6.27 ug β-carotene/g and 5.86 ug β-carotene/g, respectively). The fruits contained several phenolic compounds such as quercetin derivatives, quercitrin, isoquercitrin, and cyanidin derivatives, which may contribute differentially to the antioxidant capacity. The highest scavenging activity in the DPPH assay was found for purple-fleshed pitanga (IC₅₀ 36.78 mg/L), blackberries [IC₅₀ 44.70 (Xavante) and IC₅₀ 78.25 mg/L (Cherokee)], and araçá (IC₅₀ 48.05 mg/L), which also showed the highest FRAP, followed by orange- and red-fleshed pitanga. Our results revealed that some fruits grown in southern Brazil such as purple-fleshed pitanga, blackberries, and araçá are rich sources of phenolic compounds and have great antioxidant activity.     

Cytotoxic and bioactive properties of different color tulip flowers and degradation kinetic of tulip flower anthocyanins

This study was conducted to determine the potential use of anthocyanin-based extracts (ABEs) of wasted tulip flowers as food/drug colorants. For this aim, wasted tulip flowers were samples and analyzed for their bioactive properties and cytotoxicity. Total phenolic contents of the extracts of the claret red (126.55 mg of gallic acid equivalent (GAE)/g dry extract) and orange–red (113.76 mg GAE/g dry extract) flowers were the higher than those of the other tulip flowers. Total anthocyanin levels of the violet, orange–red, claret red and pink tulip flower extracts were determined as 265.04, 236.49, 839.08 and 404.45 mg pelargonidin 3-glucoside/kg dry extract, respectively and these levels were higher than those of the other flowers. The extracts were more effective for the inhibition of Listeria monocytogenes, Staphylococcus aureus and Yersinia enterocolitica compared to other tested bacteria. Additionally, the cytotoxic effects of five different tulip flower extracts on human breast adenocarcinoma (MCF-7) cell line were investigated. The results showed that the orange red, pink and violet extracts had no cytotoxic activity against MCF-7 cell lines while yellow and claret red extracts appeared to be toxic for the cells. Overall, the extracts of tulip flowers with different colors possess remarkable bioactive and cytotoxic properties.     

Protection of DNA and erythrocytes from free radical induced oxidative damage by black gram (Vigna mungo L.) husk extract

Antioxidants present in various plant tissues exhibit health benefits by scavenging reactive oxygen species generated under various pathophysiological conditions. In the present study, bioactive compounds from black gram husk were extracted with water and the protection of black gram husk (BGH) extract against oxidative damage in DNA and erythrocytes were studied. BGH extract had total polyphenol content of 59 mg of gallic acid equivalents (GAE). The phenolic acids identified in the extract using RP-HPLC were gallic, protocatechuic, gentisic and ferulic acids. The extract showed good antioxidant properties. The IC₅₀ value for DPPH radical scavenging activity was found to be 3.92 μg of GAE. The BGH extract also showed α-glucosidase inhibition and the IC₅₀ value was found to be 2.78 μg of GAE. The oxidative hemolysis caused by hydrogen peroxide in rat erythrocytes was inhibited by BGH extract in a dose dependent manner. The IC₅₀ values for BGH extract and BHA for hemolysis were 11.5 and 14 μg of GAE, respectively. Morphological changes in erythrocyte membrane caused by hydrogen peroxide were protected by BGH extract. As BGH extract exhibited various antioxidant properties in different systems, it could be used as a functional food or nutraceutical product for health benefits.     

A novel strategy to improve the recovery of phenolic compounds from Pistacia lentiscus L. fruits using design-based statistical modeling for ultrasound-deep eutectic solvents extraction and the evaluation of their antioxidant potential

Recently, there has been increasing interest in using alternative green technologies for the isolation of bioactive metabolites from medicinal plants. This study was designed to select the optimal solvent for phenolic compounds (TPC) extraction from Pistacia lentiscus L. black fruits (PBF) and the development of an experimental model by response surface methodology using ultrasound-assisted deep eutectic solvents (UAE-DES). The characterization and the antioxidant capacity of PBF phytochemicals using a multi-test system in-vitro were investigated. The highest amount of phenolic compounds (TPC: 183.95 ± 0.01 mg GAE/Gdw) was obtained using choline chloride-acetic acid solvent DES, under the optimum extraction conditions: 28.3% of water percentage, 40 °C of extraction temperature, and 18 min of extraction time. Moreover, DES extract had a more important antioxidant capacity with no significant difference compared to the control (Ascorbic acid). Furthermore, HPLC-DAD and TLC analysis indicated the presence of rutin and Cyanidin-3-glycoside in fraction number 4 after fractionation using the HP-20 diaion resin column. This extraction media has proved to be an alternative approach for the extraction of bioactive compounds as a sustainable and safe extraction media for pharmaceutical and industrial applications.     

Protection against hydrogen peroxide induced oxidative damage in rat erythrocytes by Mangifera indica L. peel extract

Phytochemicals such as polyphenols and carotenoids are gaining importance because of their contribution to human health and their multiple biological effects such as antioxidant, antimutagenic, anticarcinogenic and cytoprotective activities and other therapeutic properties. Mango peel is a major by-product in pulp industry and it contains various bioactive compounds like polyphenols, carotenoids and others. In the present study, the protective effect of peel extracts of unripe and ripe mango fruits of two varieties namely, Raspuri and Badami on hydrogen peroxide induced hemolysis, lipid peroxidation, degradation of membrane proteins and its morphological changes are reported. The oxidative hemolysis of rat erythrocytes by hydrogen peroxide was inhibited by mango peel extract in a dose dependent manner. The IC₅₀ value for lipid peroxidation inhibition on erythrocyte ghost membrane was found to be in the range of 4.5–19.3 μg gallic acid equivalents. The mango peel extract showed protection against membrane protein degradation caused by hydrogen peroxide. Morphological changes to erythrocyte membrane caused by hydrogen peroxide were protected by mango peel extract. The results demonstrated that mango peel extracts protected erythrocytes against oxidative stress and may impart health benefits and it could be used as a valuable food ingredient or a nutraceutical product.     

Antioxidant and hepatoprotective effects of Schisandra chinensis pollen extract on CCl4-induced acute liver damage in mice

The aim of the present study was to investigate the antioxidant and hepatotective effects of Schisandra chinensis pollen extract (SCPE) on CCl₄-induced acute liver damage in mice. Total phenolic content, total flavonoid content, individual phenolic compounds and antioxidant activities (1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, chelating activity, and reducing power assay) were determined. In vivo study, SCPE (10, 20 and 40 g/kg) administered daily orally for 42 days prior to CCl₄-intoxicated. Our results showed that SCPE had high total phenolic content (53.74 ± 1.21 mg GAE/g), total flavonoid content (38.29 ± 0.91 mg Rutin/g), quercetin and hesperetin may be the major contributor to strong antioxidant activities. Moreover, SCPE significantly prevented the increase in serum ALT and AST level in acute liver damage induced by CCl₄, decreased the extent of malondialdehyde (MDA) formation in liver and elevated the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in liver. The results indicated that SCPE has strong antioxidant activities and significant protective effect against acute hepatotoxicity induced by CCl₄, and have been supported by the evaluation of liver histopathology in mice. The hepatoprotective effect may be related to its free radical scavenging effect, increasing antioxidant activity and inhibiting lipid peroxidation.     

ESG approach in the valorization of cocoa (Theobroma cacao) by-products by subcritical water: Application in the cosmetic industry

In this research valorization potentials of cocoa hull extracts in cosmetic industry, following Environmental, Social, and Governance (ESG) criteria, have been investigated and reported, presenting increased value of this biowaste. The extracts of cocoa hull obtained by subcritical water were characterized in respect to chemical composition and certain bioactive properties, and were used to develop functional cosmetic formulation. In this work cocoa hull of cocoa beans originating from different geographical locations (Ivory Coast, Ghana, Togo, Grenada) were extracted by subcritical water to obtain functional extracts rich in valuable compounds. The extracts were characterized in respect to their total proteins (10–27%), total phenols (37–45 mg GAE/g) and total flavonoids (14–21 mg RE/g) contents. In addition, the minerals K (41–60 mg/100 g), Na (0.78–1.17 mg/100 g), and Ca (2.47–5.94 mg/100 g) were also quantified. Antiradical activity against DPPH (IC₅₀ ～ 11–13 μg/ml) and ABTS (IC₅₀ ～ 7–9 μg/ml) radicals, as well as total antioxidant activity (～14–20 mg EAK/100 g DE), were determined and compared for all extracts. The extract with the highest antioxidant and antiradical activity was used for the formulation of a functional cosmetic product – a day cream with sun protective properties and added qualities. The prepared facial cream was analysed in respect to basic quality parameters for cosmetic products, proving the safety of the newly developed product based on subcritical water extracts of cocoa hull. The application of subcritical water extraction, as a green technology, can significantly enhance the ESG development in the cosmetic industry.     

Metabolic profile of the bioactive compounds of burdock (Arctium lappa) seeds, roots and leaves

In this work the bioactive metabolic profile, the antioxidant activity and total phenolic content of burdock (Arctium lappa) seeds, leaves and roots were obtained. TEAC values and total phenolic content for hydro-alcoholic extracts of burdock ranged from 67.39 to 1.63 μmol Trolox equivalent/100 g dry weight (DW), and from 2.87 to 45 g of gallic acid equivalent/100 g DW, respectively. Phytochemical compounds were analyzed by liquid chromatography coupled to electrospray tandem mass spectrometry (LC/MS/MS) in negative mode. The main compounds of burdock extracts were caffeoylquinic acid derivatives, lignans (mainly arctiin) and various flavonoids.The occurrence of some phenolic acids (caffeic acid, chlorogenic acid and cynarin) in burdock seeds; arctiin, luteolin and quercetin rhamnoside in burdock roots; phenolic acids, quercetin, quercitrin and luteolin in burdock leaves was reported for the first time.     

Protective effect of extract of Crataegus pinnatifida pollen on DNA damage response to oxidative stress

The protective effect of extract of Crataegus pinnatifida (Rosaceae) pollen (ECPP) on the DNA damage response to oxidative stress was investigated and assessed with an alkaline single-cell gel electrophoresis (SCGE) assay and pBR322 plasmid DNA breaks in site-specific and non-site-specific systems. Total phenolic content, total flavonoid content, individual phenolic compounds, antioxidant activities (1,1-diphenyl-2-picrylhydrazyl (DPPH), radical scavenging activity, FRAP, and chelating activity) were also determined. The results showed that ECPP possessed a strong ability to protect DNA from being damaged by hydroxyl radicals in both the site-specific system and the non-site-specific system. It also exhibited a cytoprotection effect in mouse lymphocytes against H₂O₂-induced DNA damage. These protective effects may be related to its high total phenolic content (17.65 ± 0.97 mg GAE/g), total flavonoid content (8.04 ± 0.97 mg rutin/g), strong free radical scavenging activity and considerable ferrous ion chelating ability (14.48 ± 0.21 mg Na₂EDTA/g).     

In vitro cytotoxicity, α-glucosidase inhibition,antioxidant, and free radical scavenging activities of Illicium griffithii Hook. f. & Thoms fruits

Illicium griffithii is a medicinal tree species of the temperate broad-leaved forests of North East India; its fruits are used in the pharmaceutical and spice industries. The fruits are used medicinally to treat cough, sinusitis, toothache, regurgitating, dyspepsia, abdominal pain, and food poisoning and are considered carminative, stomachic, and glactagogic. The present study was aimed to evaluate the cytotoxicity, α-glucosidase inhibitory potential, antioxidant, and free radical scavenging activities of hexane, ethyl acetate, and methanol extracts of I. griffithii fruits. Ethyl acetate extract (EAE) exhibited 78.7 % toxicity at the dose of 500 μg/ml with IC₅₀ value of 300 μg/ml against A549 human adenocarcinoma lung cancer cell line, 50 % α-glucosidase inhibition at 810.32 ± 1.28 μg/ml concentration, and potent scavenging activity at 1,000 μg/ml on DPPH (91.12 % ± 2.08), CUPRAC (2.384 ± 0.03), reducing power (0.847 ± 0.02), lipid peroxidation (55.52 % ± 1.56), hydroxyl (75.83 % ± 1.47), and DMPD (76.12 % ± 1.35). It additionally showed maximum activity at 300 μg/ml on total antioxidant activity (0.290 ± 0.04 GAE mg/g) and FRAP (2.150 ± 0.23 mM Fe²⁺/g). The results demonstrated that EAE possessed marked activity in all the tested biological parameters. On further fractionation, EAE gave an active fraction F3. Two phenolic compounds were isolated and identified (3,4-dihydroxybenzoic acid and 3,4,5-trihydroxybenzoic acid) from this fraction for the first time. I. griffithii showed promising cytotoxic and antioxidant activities.     

Anticancer,antioxidant and antibiotic activities of mushroom Ramaria flava

Ramaria flava is a species of edible mushroom with some bioactivity. The anticancer, antioxidant and antibiotic activities and chemical composition of R. flava ethanol extract (EE) were evaluated. The present study exhibited that the EE displayed the strongest inhibitory activity against tumor cell MDA-MB-231 with an IC₅₀ value of 66.54 μg/mL in three tested tumor cell lines, and the inhibition percent was 71.66% at the concentration of 200 μg/mL (MTT assay). The total phenolic compounds varied among four fractions of the EE from 6.66 to 61.01 mg gallic acid equivalent (GAE) per g dry weight. Water fraction exhibited high DPPH and OH radical-scavenging activities with low IC₅₀ values of 5.86 and 18.08 μg/mL, respectively. Meanwhile, three phenolic compounds from water fraction were also identified by HPLC. The antibiotic activities of the EE were evaluated against three microorganisms and three fungi strains by means of the agar well diffusion method and the poisoned medium technique, respectively. The EE also showed moderate antibiotic activities. These results suggest that R. flava could hold a good potential source for human health.     

Wild mushrooms Clitocybe alexandri and Lepista inversa: In vitro antioxidant activity and growth inhibition of human tumour cell lines

The in vitro antioxidant and growth inhibitory activity of extracts obtained from two Portuguese wild mushrooms (Clitocybe alexandri and Lepista inversa) was studied in human tumour cell lines. The extracts were phenolic (methanolic and ethanolic) and polysaccharidic (boiling water). The antioxidant activity assays included evaluation of radical-scavenging capacity, reducing power and inhibition of lipid peroxidation measured in liposome solutions. Extract-induced cell growth inhibition was measured in four different tumour cell lines (lung, breast, colon and gastric cancer) using the SRB assay. The polysaccharidic extract of L. inversa was the most potent as antioxidant (EC₅₀ < 1.8 ± 0.1 mg/ml), while the phenolic ethanolic extract of C. alexandri was the most potent as inhibitor of growth of the studied cancer cell lines (GI₅₀ < 26.0 ± 1.3 μg/ml). Together, these activities indicate that these mushrooms are promising sources of bioactive compounds.     

Total Phenolic Content and Antioxidant Activity of Morinda tinctoria Leaves

The antioxidant activity and total phenolic content of Morinda tinctoria leaves was evaluated. The successively extracted leaves of Morinda tinctoria using various solvents was analyzed for their total phenolic content. The extracts were subjected to column chromatography for the isolation of bioactive molecules. In vitro antioxidant activity was evaluated by employing different assays, including 2,2-diphenyl-1-picrylhydrazyl, nitric oxide scavenging assay and phosphomolybdenum reducing power assay. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging efficacy of hexane extract is significant at higher concentration (500 μg/ml-91.2±0.05%) and the efficacy at lower concentration is more significant for ethyl acetate extract (100 μg/ml - 65.1±0.05%). The total phenolic content was highest in methanol extract (5.30±0.011 μg/mg). Cynarin, a hydroxy cinnamic acid was isolated from chloroform extract; oleuropein, a polyphenolic iridoid was isolated from methanol extract. The results obtained suggeted that Morinda tinctoria leaf extracts possessed antioxidant properties and might offer protection from free radicals. Two compounds, cynarin and oleuropein were reported for the first time from Morinda tinctoria leaves.