Essential oil composition and antioxidant activities of Curcuma aromatica Salisb.

The chemical composition of the hydro-distilled essential oil from leaves of Curcuma aromatica Salisb. was analysed by GC–MS. Twenty-three compounds representing 94.29% of the total oil were identified. The antioxidant activities of the oil and various extracts of C. aromatica were evaluated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical-scavenging assays. The oil and methanol extract showed potent DPPH radical-scavenging activities (IC₅₀ = 14.45 and 16.58 μg/ml, respectively), which were higher than butylated hydroxyanisole (IC₅₀ = 18.27 μg/ml). The extracts also exhibited remarkable superoxide radical-scavenging activities (IC₅₀ = 22.6–45.27 μg/ml) and the activity in the methanol extract was superior to all other extracts (IC₅₀ = 22.6 μg/ml). Furthermore, the amount of total phenolic compounds was determined and its content in ethyl acetate extract was the highest as compared to other extracts. The results indicate that the oil and extracts of C. aromatica could serve as an important bio-resource of antioxidants for using in the food industries.     

Evaluation of anti-oxidant activities and total phenolic content of Chromolaena odorata

The aim of this study was to assess the in vitro potential of chloroform extract of Chromolaena odorata leaves. The DPPH activity of the extract (0.1–5 mg/ml) was increased in a dose dependent manner, which was found in the range of 23.48–91.61% as compared to ascorbic acid (33.69–94.10%). The IC50 values of chloroform extract in DPPH radical, hydroxyl radical, nitric oxide, ABTS radical were obtained to be 0.31, 0.43, 0.28 and 1.32 mg/ml, respectively. However, the IC50 values for the standard ascorbic acid were noted to be 0.24, 0.41, 0.23 and 1 mg/ml, respectively. Measurement of total phenolic content of the chloroform extract of C. odorata was achieved using Folin–Ciocalteau reagent containing 242.2 mg/g of phenolic content, which was found significantly higher when compared to reference standard gallic acid. The results obtained in this study clearly indicate that C. odorata has a significant potential to use as a natural anti-oxidant agent.     

Antioxidant and antidermatophytic activities of essential oil and extracts of Metasequoia glyptostroboides Miki ex Hu

This study was undertaken to assess the antioxidant and antidermatophytic potential of the essential oil and extracts (hexane, chloroform, ethyl acetate and methanol) of Metasequoia glyptostroboides Miki ex Hu. Antioxidant activity was evaluated by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The free radical scavenging activities of the oil and ethyl acetate extract were found to be superior (IC₅₀ = 9.1 and 14.24 μg/ml, respectively) as compared to butylatedhydroxyanisole (BHA), (IC₅₀ = 18.27 μg/ml). Also the ethyl acetate extract revealed the highest phenolic contents (93.26 mg/g of dry wt) as compared to the other extracts. Further, oil (1250 μg/disc) and extracts (1750 μg/disc) revealed 35.33–67.66 and 18.0–53.3% antidermatophytic effect, respectively, along with their respective MIC values (62.5–500 and 250–4000 μg/ml) against Trichophyton rubrum KCTC 6345, T. rubrum KCTC 6375, T. rubrum KCTC 6352, T. mentagrophytes KCTC 6085, T. mentagrophytes KCTC 6077, T. mentagrophytes KCTC 6316, Microsporum canis KCTC 6591, M. canis KCTC 6348 and M. canis KCTC 6349. The oil also had a strong detrimental effect on spore germination as well as concentration and time-dependent kinetic inhibition of M. canis KCTC 6591.     

In vitro and in vivo antioxidant activity of Symplocos cochinchinensis S. Moore leaves containing phenolic compounds

Methanol extract of Symplocos cochinchinensis S. Moore leaves was evaluated for its in vitro and in vivo antioxidant activity. The total phenolic content of the extract was 230 mg of gallic acid equivalents/g extract. The extract showed very good scavenging activity on 2,2-diphenyl-picrylhydrazyl (DPPH) (IC₅₀ 620.30 ± 0.14 μg/ml), hydroxyl (IC₅₀ 730.21 ± 1.05 μg/ml), nitric oxide (IC₅₀ 870.31 ± 0.19 μg/ml) radicals, as well as high reducing power. The extract also showed strong suppressive effect on lipid peroxidation. In in vivo study CCl₄ induced oxidative stress produced significant increase in SGOT, SGPT and LDH levels along with reduction in liver SOD, CAT, GSH and GPx levels. Pre-treatment of rats with the extract (250 and 500 mg/kg) for 7 days showed significant reduction in the levels of SGOT, SGPT and LDH compared to CCl₄ treated rats. SOD, CAT, GSH and GPx levels were increased significantly due to treatment with the extract. The activity of the extract was comparable to the standard drug, silymarin (25 mg/kg). The results suggest that the leaves of S. cochinchinensis are a source of natural antioxidants.     

In vitro antioxidant activity and total phenolic content of ethanolic leaf extract of Stevia rebaudiana Bert.

The aim of this study was to assess the in vitro potential of ethanolic leaf extract of Stevia rebaudiana as a natural antioxidant. The DPPH activity of the extract (20, 40, 50, 100 and 200 μg/ml) was increased in a dose dependent manner, which was found in the range of 36.93–68.76% as compared to ascorbic acid 64.26–82.58%. The IC₅₀ values of ethanolic extract and ascorbic acid in DPPH radical scavenging assay were obtained to be 93.46 and 26.75 μg/ml, respectively. The ethanolic extract was also found to scavenge the superoxide generated by EDTA/NBT system. Measurement of total phenolic content of the ethanolic extract of S. rebaudiana was achieved using Folin–Ciocalteau reagent containing 61.50 mg/g of phenolic content, which was found significantly higher when compared to reference standard gallic acid. The ethanolic extract also inhibited the hydroxyl radical, nitric oxide, superoxide anions with IC₅₀ values of 93.46, 132.05 and 81.08 μg/ml, respectively. However, the IC₅₀ values for the standard ascorbic acid were noted to be 26.75, 66.01 and 71.41 μg/ml respectively. The results obtained in this study clearly indicate that S. rebaudiana has a significant potential to use as a natural antioxidant agent.     

Antimicrobial and antioxidant activities of Russula delica Fr.

Russula delica Fr. is a well known macrofungi which is used as a food in Turkey. The ethanolic extract of R. delica exhibited antimicrobial activity against some of the tested foodborne and spoilage bacteria. The phenolic composition of R. delica ethanolic extract was analyzed by high performance liquid chromatography (HPLC). The major component in R. delica ethanolic extract was catechin (5.33 mg/L). Antioxidant activities of the ethanolic extract of R. delica was evaluated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging and chelating ability on ferrous ions assays. Scavenging effect on DPPH radicals was 26% at 10 mg/ml and chelating effects on ferrous ions was 58% at 5 mg/ml. In addition, the amounts of total phenol content (6.23 mg/g), ascorbic acid (2.93 mg/g), β-carotene (0.11 mg/g) and lycopene (0.03 mg/g) in the macrofungi ethanolic extract were determined.     

Essential oil composition and antioxidant and antimicrobial properties of the aerial parts of Salvia eremophila Boiss. from Iran

The essential oil composition and in vitro antioxidant and antimicrobial activity of the essential oil and methanol extract of Salvia eremophila were evaluated in this research. GC and GC/MS analysis of the plant essential oil resulted in the identification of 28 compounds representing 99.24% of the oil. Borneol (21.83%), α-pinene (18.80%), bornyl acetate (18.68%) and camphene (6.54%) were detected as the major components consisting 65.85% of the oil. The plant essential oil and methanol extract were also subjected to screenings for the evaluation of their antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene–linoleic acid tests. While the plant essential oil showed only weak antioxidant activities, its methanol extract was considerably active in both DPPH (IC₅₀ = 35.19 μg/ml) and β-carotene–linoleic acid (inhibition percentage: 72.42%) tests. Appreciable total phenolic content (101.25 μg/mg) was also detected for the plant methanol extract as gallic acid equivalent in the Folin–Ciocalteu test. The plant was also screened for its antimicrobial activity and good to moderate inhibitions were recorded for its essential oil and methanol extract against most of the tested microorganisms.     

Phenolic composition and biological activities of Juniperus drupacea Labill. berries from Turkey

The present study was designed to define the phenolic profile and the biological potential of berries methanol extract of Juniperus drupacea Labill. from Turkey.The total phenolic content (Folin-Ciocalteau assay) was 48.06 ± 0.99 mg GAE/g extract. The HPLC-DAD-ESI-MS analysis allowed the determination of the complete phenolic profile of J. drupacea berries. Phenolic acids represented more than 60% of the total phenolics, and tyrosol was the major one (1324 ± 0.64 μg/g extract); within the flavonoids amentoflavone was detected as the main constituent (927 ± 0.35 μg/g extract).The extract exhibited good antioxidant properties, as determined by different in vitro models: DPPH test (IC₅₀ 0.38 ± 0.02 mg/mL), reducing power (12.63 ± 0.14 ASE/mL), Fe²⁺ chelating ability (IC₅₀ 2.26 ± 0.06 mg/mL), and TBA test (IC₅₀ 2.47 ± 1.13 μg/mL).Cytotoxicity against Artemia salina was highlighted (LC₅₀ 489.47 ± 27.8 μg/mL), and a significant decrease (p ? 0.05; p ? 0.01) in HepG2 cells viability was observed at the higher concentrations (5-10 μg/mL).The extract displayed good antibacterial activity towards Gram-positive bacteria and in particular Staphylococcus aureus was the most susceptible strain (MIC 78.12 μg/mL).     

Scavenging capacity of strawberry tree (Arbutus unedo L.) leaves on free radicals

Despite strawberry tree (Arbutus unedo L.) leaves had a long use in traditional medicine due to its antiseptic, diuretic, astringent and depurative properties, the potential of their antioxidant activity are still lacking. Our study goals to assess the antioxidant and free radical scavenging potential of water, ethanol, methanol and diethyl ether extracts of A. unedo leaves. Total phenols content was achieved spectrophotometrically using Folin–Ciocalteau reagent with gallic acid as standard. Antioxidant activity was evaluated using three different methods: reducing power of iron (III)/ferricyanide complex assay, scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and scavenging effect on superoxide radicals by using the PMS–NADH–nitroblue tetrazolium system. Ethanol extracts of A. unedo leaves were the highest in reducing power (IC₅₀ 232.7 μg/mL) and DPPH scavenging effect (IC₅₀ 63.2 μg/mL) followed by water extracts (with IC₅₀ of 287.7 and 73.7 μg/mL, respectively); whereas diethyl ether extracts were the lowest. In the scavenging on superoxide radical assay, methanol extracts obtained the best results (IC₅₀ 6.9 μg/mL). For all the methods tested the antioxidant activity was concentration dependent. In accordance with antioxidant activity, highest total phenols content were found in ethanol, followed by water, methanol and diethyl ether extract. The results indicated that A. unedo leaves are a potential source of natural antioxidants.     

Chemical compositions,antifungal and antioxidant activities of essential oil and various extracts of Melodorum fruticosum L. flowers

This research presents the chemical composition antifungal and antioxidant activities of essential oils and various extracts from Melodorum fruticosum flowers. The essential oil composition of M. fruticosum flowers were investigated by GC–MS with 88 identified volatile constituents. Phenyl butanone, linalool, benzyl alcohol, α-cadinol, globulol and viridiflorol were found to be the major components, respectively. The dichloromethane extract played a major role as a remarkable fungicide according to their inhibition action against all tested pathogens followed by hexane extract, essential oil and methanol extract, respectively, along with their respective MIC values ranging from 125 to 1000 μg/ml. The dichloromethane extracts were also evaluated to be superior to all extracts tested with an IC₅₀ value of 87.6 μg/ml whereas other extracts showed their IC₅₀ values ranging from 100.13 to 194.50 μg/ml.     

Chemical composition of five wild edible mushrooms collected from Southwest China and their antihyperglycemic and antioxidant activity

Evaluation of the chemical composition and antihyperglycemic and antioxidant activity of five wild edible mushrooms (Clitocybe maxima, Catathelasma ventricosum, Stropharia rugoso-annulata, Craterellus cornucopioides and Laccaria amethystea) from Southwest China. The chemical composition assay includes proximate analysis (moisture, ash, crude protein, crude fat, total carbohydrates and total energy), bioactive compounds analysis (total phenolic, flavonoid, ascorbic acid, ergosterol, tocopherol), fatty acid analysis, amino acid analysis, phenolic compounds analysis and mineral analysis of these mushrooms. Furthermore, assays of α-glucosidase inhibitory and α-amylase inhibitory activity were used for evaluating antihyperglycemic activity of the mushrooms, and assays of reducing power, chelating effect on ferrous ions, scavenging effect on hydroxyl free radicals and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were used for evaluating antioxidant activity of the mushrooms. Based on the results, ethanolic and aqueous extract of these mushroom all showed antihyperglycemic and antioxidant potential. In particular, the aqueous extract of C. ventricosum revealed the highest α-glucosidase inhibitory activity (EC50 value 2.74 μg/mL), DPPH radical scavenging activity (EC50 value 2.86 mg/mL) and reducing power (EC50 value 0.96 mg/mL), while the aqueous extract of L. amethystea showed the highest α-amylase inhibitory activity (EC50 value 4.37 μg/mL) and metal chelating activity (EC50 value 2.13 mg/mL).     

In vitro antioxidant,antidiabetic and antilipidemic activities of Symplocos cochinchinensis (Lour.) S. Moore bark

Symplocos cochinchinesis is used in Indian system of traditional medicine to treat diabetes mellitus. The present study investigates the in vitro antioxidant, antidiabetic and antilipidemic activities of S. cochinchinensis bark methanolic extract (SCBe) in streptozotocin (STZ) induced diabetic rats. In in vitro studies SCBe showed very good scavenging activity on 2,2-diphenyl-picrylhydrazyl (DPPH) (IC₅₀ 820.34 ± 1.74 μg/ml), hydroxyl (IC₅₀ 884.19 ± 0.45 μg/ml) and nitric oxide (IC₅₀ 860.21 ± 1.18 μg/ml) radicals, as well as high reducing power. SCBe (250 and 500 mg/kg) was administered to STZ (40 mg/kg) induced diabetic rats for 28 days. SCBe showed a significant decrease in blood glucose and significant increase in plasma insulin and liver glycogen levels in treated diabetic rats. Further, SCBe showed antilipidemic activity as evidenced by significant decrease in serum TC, TG, LDL-C levels and significant increase in HDL-C level in treated diabetic rats. SCBe also restored the altered plasma enzymes (SGOT, SGPT and ALP), total protein, urea and creatinine levels to near normal. The action of SCBe was comparable to the antidiabetic drug glibenclamide. Results of this experimental study indicated that SCBe possessed antioxidant, antidiabetic and antilipidemic activities.     

Antioxidant activity of selected plant species; potential new sources of natural antioxidants

The aim of this study was to examine six plants from Serbia for their potential antioxidant activity. Therefore, six antioxidant activity assays were carried out, including: total antioxidant capacity, DPPH free-radical scavenging, the inhibitory activity toward lipid peroxidation, Fe³⁺- reducing power, Fe²⁺- chelating ability and hydroxyl radical scavenging activity. Total phenolic and flavonoid contents were also determined for each alcoholic extract. Cotinus coggygria extract contained the highest amount of total phenols (413 mg GAE /g dry extract), while the highest proportion of flavonoids was found in the Echium vulgare methanol extract (105 mg RU/g). Cotinus coggygria and Halacsya sendtneri alcoholic extracts showed the highest total antioxidant capacity (313 and 231 mg AA/g dry extract), as well as DPPH free-radical scavenging (IC₅₀ = 9 and 99 μg/ml), inhibitory activity toward lipid peroxidation (IC₅₀ = 3 and 17 μg/ml) and reducing power. Whereas, the greatest hydroxyl radical scavenging activity, as well as ferrous ion chelating ability showed Echium vulgare, Echium rubrum and Halacsya sendtneri.     

Antioxidant activity, acetylcholinesterase inhibition, iridoid content and mutagenic evaluation of Leucosideasericea

Leucosidea sericea is an important medicinal plant widely used in traditional medicine in southern Africa. Leaf and stem petroleum ether (PE), dichloromethane (DCM) and 50% aqueous methanol (MeOH) extracts were investigated for antioxidant and acetylcholinesterase inhibitory activities. The safety of the extracts was evaluated using the Ames test. In addition, the iridoid content of L. sericea stems and leaves were quantified. For DPPH radical-scavenging activity, the stem MeOH extract (EC₅₀ value: 1.6 μg/ml) was more potent than ascorbic acid (EC₅₀ value: 1.7 μg/ml). In the β-carotene-linoleic acid model system, antioxidant activity of the leaf DCM extract (89.8%) was not significantly different to that of butylated hydroxytoluene (BHT) (98.9%). All extracts showed a dose-dependent acetylcholinesterase inhibition; in terms of the IC₅₀ value, the leaf DCM extract (0.14 mg/ml) was the most potent sample. Total iridoid content was 35% higher in the stem extract than in the leaf extract. Based on the Ames test, L. sericea extracts were not mutagenic, either with or without S9 metabolic activation. These findings suggest the safety as well as the potential of L. sericea as a possible source of novel/alternative antioxidant and acetylcholinesterase inhibitory compounds.     

Antinociceptive and antioxidant potential of the crude ethanol extract of the leaves of Ageratum conyzoides grown in Bangladesh

Abstract

Context: Ageratum conyzoides Linn. (Asteraceae) is an annual herbaceous plant with a long history of traditional medicinal and agricultural uses; it is usually grown in the northeast part of Bangladesh.

Objective: The ethanol extract of the plant leaves was evaluated for preliminary phytochemical screening with its antinociceptive and antioxidant activities.

Materials and methods: The preliminary phytochemical analysis was performed on the basis of standard procedures. The analgesic activity of the extract was investigated using the acetic acid-induced writhing method in mice. Five complementary tests such as DPPH free radical scavenging, nitric oxide (NO) scavenging, reducing power, Fe⁺⁺ ion chelating ability and total phenolic content were used for determining antioxidant activities.

Results: The results of preliminary phytochemical analysis showed the presence of alkaloids, reducing sugars, saponins, gums, steroids, tannins and flavonoids. The extract possessed a significant dose-dependent DPPH free radical scavenging activity with an IC₅₀ value of 18.91?μg/ml compared to ascorbic acid (IC₅₀: 2.937?μg/ml) and butylated hydroxyanisole (IC₅₀: 5.10?μg/ml). The IC₅₀ value of the extract for NO scavenging (41.81?μg/ml) was also found to be significant compared to the IC₅₀ value of ascorbic acid (37.93?μg/ml). Moreover, the extract showed reducing power activity and Fe⁺⁺ ion chelating ability. The total phenolic amount was also calculated as quite high (378.37?mg/g of gallic acid equivalents) in the crude ethanol extract.

Discussion and conclusion: Therefore, the obtained results tend to suggest the antinociceptive and antioxidant activities of the ethanol extract of the plant leaves and justify its use in folkloric remedies.     

Human cancer cell antiproliferative and antioxidant activities of Juglans regia L.

Several studies suggest that regular consumption of nuts, mostly walnuts, may have beneficial effects against oxidative stress mediated diseases such as cardiovascular disease and cancer. Walnuts contain several phenolic compounds which are thought to contribute to their biological properties. The present study reports the total phenolic contents and antioxidant properties of methanolic and petroleum ether extracts obtained from walnut (Juglans regia L.) seed, green husk and leaf. The total phenolic contents were determined by the Folin–Ciocalteu method and the antioxidant activities assessed by the ability to quench the stable free radical 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and to inhibit the 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative hemolysis of human erythrocytes. Methanolic seed extract presented the highest total phenolic content (116 mg GAE/g of extract) and DPPH scavenging activity (EC₅₀ of 0.143 mg/mL), followed by leaf and green husk. In petroleum ether extracts, antioxidant action was much lower or absent. Under the oxidative action of AAPH, all methanolic extracts significantly protected the erythrocyte membrane from hemolysis in a time- and concentration-dependent manner, although leaf extract inhibitory efficiency was much stronger (IC₅₀ of 0.060 mg/mL) than that observed for green husks and seeds (IC₅₀ of 0.127 and 0.121 mg/mL, respectively). Walnut methanolic extracts were also assayed for their antiproliferative effectiveness using human renal cancer cell lines A-498 and 769-P and the colon cancer cell line Caco-2. All extracts showed concentration-dependent growth inhibition toward human kidney and colon cancer cells. Concerning A-498 renal cancer cells, all extracts exhibited similar growth inhibition activity (IC₅₀ values between 0.226 and 0.291 mg/mL), while for both 769-P renal and Caco-2 colon cancer cells, walnut leaf extract showed a higher antiproliferative efficiency (IC₅₀ values of 0.352 and 0.229 mg/mL, respectively) than green husk or seed extracts. The results obtained herein strongly indicate that walnut tree constitute an excellent source of effective natural antioxidants and chemopreventive agents.     

Phyllanthus emblica (Amla) methanolic extract regulates multiple checkpoints in 15-lipoxygenase mediated inflammopathies: Computational simulation and in vitro evidence

Amla (Phyllanthus emblica) has long been used in traditional folk medicine to prevent and cure a variety of inflammatory diseases. In this study, the antioxidant activity (DPPH scavenging and reducing power), anti-inflammatory activity (RBC Membrane Stabilization and 15-LOX inhibition), and anticoagulation activity (Serin protease inhibition and Prothrombin Time assays) of the methanolic extract of amla were conducted. Amla exhibited a substantial amount of phenolic content (TPC: 663.53 mg GAE/g) and flavonoid content (TFC: 418.89 mg GAE/g). A strong DPPH scavenging effect was observed with an IC₅₀ of 311.31 µg/ml as compared to standard ascorbic acid with an IC₅₀ of 130.53 µg/ml. In reducing power assay, the EC₅₀ value of the extract was found to be 196.20 µg/ml compared to standard ascorbic acid (EC₅₀ = 33.83 µg/ml). The IC₅₀ value of the RBC membrane stabilization and 15-LOX assays was observed as 101.08 µg/ml (IC₅₀ of 58.62 µg/ml for standard aspirin) and 195.98 µg/ml (IC₅₀ of 19.62 µg/ml for standard quercetin), respectively. The extract also strongly inhibited serine protease (trypsin) activity with an IC₅₀ of 505.81 µg/ml (IC₅₀ of 295.44 µg/ml for standard quercetin). The blood coagulation time (PTT) was found to be 11.91 min for amla extract and 24.11 min for standard Warfarin. Thus, the findings of an in vitro study revealed that the methanolic extract of amla contains significant antioxidant, anti-inflammatory, and anticoagulation activity. Furthermore, in silico docking and simulation of reported phytochemicals of amla with human 15-LOXA and 15-LOXB were carried out to validate the anti-inflammatory activity of amla. In this analysis, epicatechin and catechin showed greater molecular interaction and were considerably stable throughout the 100 ns simulation with 15-lipoxygenase A (15-LOXA) and 15-lipoxygenase B (15-LOXB) respectively.     

Antioxidant and antibacterial activities of the leaf essential oils of Himalayan Lauraceae species

The leaf essential oils from seven Himalayan Lauraceae species viz. Neolitsea pallens, Lindera pulcherrima, Dodecadenia grandiflora, Persea duthiei, Persea odoratissima, Persea gamblei and Phoebe lanceolata exhibited potent antioxidant and antibacterial activities. The in vitro antioxidant activity was assessed by using β-carotene bleaching assay, reducing power, DPPH radical scavenging and inhibition of lipid peroxidation methods. The oils of D. grandiflora and L. pulcherrima showed a potent free radical scavenging activity as evidenced by low IC₅₀ value for DPPH radical (0.032 mg/ml and 0.087 mg/ml, respectively) and inhibition of lipid peroxidation (in between IC₅₀ = 0.44 mg/ml and IC₅₀ = 0.74 mg/ml, respectively). The oils were tested against three Gram negative (Escherichia coli, Salmonella enterica enterica and Pasturella multocida) and one Gram positive (Staphylococcus aureus) bacteria at different concentrations using disc diffusion and tube dilution methods. The inhibition zones (IZ) and MIC values for bacterial strains were in the range of 8.7–22.0 mm and 3.90–31.25 μl/ml, respectively.     

Characterization of increased phenolic compounds from fermented Bokbunja (Rubus coreanus Miq.) and related antioxidant activity

This study examined the changes in the phenolic acid-content and antioxidant activity of Rubi Fructus (RF), the fruit of Rubus coreanus Miq., after fermentation with yeast (Saccharomyces cerevisiae). The phenolic acids were fractionated into three forms, free (Fr. A), ester (Fr. B), and insoluble-bound phenolic acids (Fr. C) and quantified by high performance liquid chromatography with a diode array detector (HPLC-DAD). This method was validated and allowed the successful identification of 11 phenolic acids in the RF extracts. HPLC-DAD analysis of the samples showed substantial increases in the levels of protocatechuic, vanillic and p-coumaric acid as the result of yeast fermentation. The total phenolic content (TPH) was also increased by fermentation. The total phenolics in Fr. A and Fr. B increased from 117 to 173 mg GAE/100 g and from 488 to 578 mg GAE/100 g, respectively. The total phenolics in Fr. C decreased from 264 to 175 mg GAE/100 g. The antioxidant activity of the fermented RF was measured as the 1,1-diphenoly-2-picrylhydrazyl (DPPH) radical scavenging capacity, which is expressed as the IC₅₀. The IC₅₀ for Fr. A and Fr. B decreased from 5.9 to 4.0 mg/ml (mg of dried RF equiv./ml) and from 1.2 to 0.8 mg/ml, respectively. In Fr. C, the IC₅₀ value increased from 2.1 to 2.8 mg/ml. In summary, the fermented RF had a higher total phenolic content and better DPPH radical-scavenging activity than the unfermented material.     

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.