Essential oil composition and antioxidant activity of Thymus longicaulis C. Presl subsp. longicaulis var. longicaulis

This study is designed to examine the chemical composition and in vitro antioxidant activity of the hydrodistillated essential oil and various extracts obtained from Thymus longicaulis subsp. longicaulis var. longicaulis. GC and GC–MS analysis of the essential oil were resulted in determination 22 different compounds, representing 99.61% of total oil. γ-terpinene, thymol and p-cymene were determined as the major compounds of the oil (27.80, 27.65 and 19.38%, respectively). Antioxidant activities of the samples were determined by four different test systems namely β-carotene/linoleic acid, DPPH, reducing power and chelating effect. Essential oil showed the highest antioxidant activity in β-carotene/linoleic acid system among the experiments examined. In the case of other test systems, in general, methanol and water extracts exhibited the strongest activity profiles. Especially, reducing power of water extract was found superior than those of synthetic antioxidants. As well as the antioxidant activities of the extracts, they were evaluated in terms of their total phenolic and flavonoid contents. Hexane and water extracts were found to be rich-in phenolics. However, flavonoids were determined in the highest level in methanol extract.     

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.     

Effect of synthetic antioxidants on hydrogen peroxide formation, oxyferro cytochrome P-450 concentration and oxygen consumption in liver microsomes

Synthetic antioxidants lead in vitro to increased H2O2 formation in rat liver and lung microsomes and in guinea pig and hamster liver microsomes. Butylated hydroxyanisole and ethoxyquin are more potent than propyl-, octyl-, and dodecyl gallate; butylated hydroxytoluene is only weakly active. Extra production of H2O2 is maximal at antioxidant concentrations between 50 and 500 microM and is dependent on the concentration of NADPH. It is paralleled by increased microsomal oxygen consumption and decreased concentration of oxycytochrome P-450 and is enhanced by pretreatment of the animals with phenobarbital. Both the endogenous and the antioxidant-stimulated H2O2 production are inhibited by metyrapone. In vivo administration of ethoxyquin and butylated hydroxyanisole in the diet leads to decreased oxycytochrome P-450 concentrations but not to increased H2O2 formation in liver microsomes. No extra production of H2O2 was observed in a glucose oxidase or xanthine oxidase system; rather, inhibition occurred in the latter system. Our data suggest that antioxidants enhance the oxidase function of cytochrome P-450. This effect is discussed in view of the known toxicity of these food additives.     

Chemical composition,antimicrobial and antioxidant activities of the essential oils of Sideritis erythrantha Boiss. and Heldr. (var. erythrantha and var. cedretorum P.H. Davis) endemic in Turkey

In the present study, chemical compositions, antimicrobial and antioxidant activities of the essential oils of Sideritis erythrantha var. erythrantha (SE) and Sideritis erythrantha var. cedretorum (SC), which are endemic taxa in Turkey, were investigated. The essential oils obtained by hydrodistillation were analyzed by gas chromatography–mass spectrometry (GC–MS). α-Pinene was the major component of the essential oils of SC and SE. SC essential oil was as effective as antibiotic against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin resistant Enterococcus faecalis (VRE), ampicillin resistant Haemophilusinfluenzae and vancomycin sensitive E. faecalis. Similarly, SE essential oil was also as effective as antibiotic against VRE and ampicillin resistant H. influenzae. Antioxidant activities of the essential oils of SC and SE were determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH), β-carotene/linoleic acid and reducing power. Both essential oils exhibited weak antioxidant activity. This is the first report on antimicrobial and antioxidant activities of the essential oils of SC and SE.     

In vitro assays of the antibacterial and antioxidant activity of aqueous leaf extracts from different Prunus salicina Lindl. cultivars

The growing interest in the substitution of synthetic food antioxidants and antimicrobial additives by natural ones has fostered research on vegetable sources and on the screening of raw materials, for identifying new antioxidants and antimicrobial natural agents. The aim of the present study was to assess total phenolic contents and determine polyphenolic composition, related antioxidative and antimicrobial properties of plum leaves extracts from six cultivars. It was observed that the content of total phenolic compounds was cultivar dependent. High antioxidant capacity has been observed and related to the relative amounts of polyphenolic compounds with good antioxidant properties. The antimicrobial activity was confirmed against Listeria innocua and Escherichia coli, and it has found to be related with the high phenolic contents. Our results suggest that the use of plum leaf extracts is a feasible alternative as antibacterial and antioxidant agents to prevent the deterioration of stored foods by bacteria and oxidation.     

Antioxidant and antimicrobial properties of Moltkia petraea (Tratt.) Griseb. flower,leaf and stem infusions

Antioxidant and antimicrobial activities as well as the quantity of phenolic substances (total phenol, flavonoid and phenolic acid contents) were determined in aqueous extracts of leaves, stems and flowers of Moltkia petraea (Tratt.) Griseb. from two mountainous localities (Sveti Jure and Snije?nica) in Croatia. In addition, the profile of phenolic acids was analyzed by UPLC–MS/MS. Antioxidant activities of all extracts in different test systems, namely the DPPH radical scavenging, reducing power assay and chelating activity, increased with extract concentration. Activity of the extracts from Snije?nica in β-carotene-linoleic acid assay did not differ from the activity of standard, BHA. The leaf extracts from Snije?nica demonstrated superior antioxidant activity in most of the assays, while the stem extract from the same locality was the most effective Fe²⁺ ion chelator. In general, the extracts from Snije?nica were more effective antioxidants than the corresponding extracts from Sveti Jure. The aqueous extracts of M. petraea did not show antimicrobial activity against bacteria and fungi tested in the diffusion and dilution assays.     

Effect of Zataria multiflora Boiss. essential oil on growth and aflatoxin formation by Aspergillus flavus in culture media and cheese

The effect of Zataria multiflora Boiss. essential oil (EO) against growth, spore production and aflatoxin formation by Aspergillus flavus ATCC 15546 was investigated in synthetic media as well as Iranian ultra-filtered white cheese in brine. EO effectively inhibited radial growth and spore production on potato dextrose agar (PDA) in a dose-dependent manner. At 200 ppm, the radial growth and sporulation reduced by 79.4% and 92.5%, respectively. The growth was completely prevented at EO ? 400 ppm on PDA, and minimum fungicidal concentration (MFC) of the oil was estimated at 1000 ppm. The oil also significantly suppressed mycelial growth and aflatoxin synthesis in broth medium at all concentrations tested (P < 0.05). At 150 ppm of EO, the mycelial growth and aflatoxin accumulation reduced by 90% and 99.4%, respectively. The EO at all concentrations tested, had an inhibitory effect against radial fungal growth and aflatoxin production by A. flavus in cheese. However, no concentration of EO examined was able to completely inhibit the growth and aflatoxin production in cheese. The results suggested the potential substitution of the antifungal chemicals by this EO as a natural inhibitor to control the growth of molds in foods such as cheese.     

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.     

Antioxidant and antiacetylcholinesterase activities of chard (Beta vulgaris L. var. cicla)

Plants have been used for many years as a source of traditional medicine to treat various diseases and conditions. Many of these medicinal plants are also excellent sources for phytochemicals, many of which contain potent antioxidant and antiacetylcholinesterase activities. Chard (Beta vulgaris L. var. cicla) is widely spread in Turkey and used as an antidiabetic in traditional medicine. In the present study, the antioxidant activity and acetylcholinesterase inhibitor capacity of chard were examined. In addition, proline level of chard was determined. The antioxidant activity of water extract of chard was evaluated using different antioxidant tests. The results were compared with natural and synthetic antioxidants. The results suggest that chard may provide a natural source of antioxidant and antiacetylcholinesterase activities and proline content.     

Bioscreening of Australian olive mill waste extracts: biophenol content, antioxidant, antimicrobial and molluscicidal activities.

The biophenolic fraction was characterized in olive mill waste (OMW) obtained as a by-product from processing of Mission and Frantoio olive fruit. OMW produced from the Mission fruit contained higher total phenol content. Individual biophenols with the exception of verbascoside and a hydroxytyrosol-secoiridoid were also present at higher concentrations in the OMW produced from Mission cultivar. Antioxidant activities were measured in aqueous (DPPH) and emulsion (BCBT) systems. The Frantoio extract was more active than the Mission extract in the DPPH assay - EC(50) values were 28.3+/-1.7 ppm and 34.7+/-1.7 ppm, respectively. Activities were reversed in the BCBT, with the Mission extract (EC(50) 60.6+/-2.3 ppm) more potent than the Frantoio extract (EC(50) 79.9+/-2.0 ppm), and this may be related to the more lipophilic nature of the Mission extract. Both extracts showed broad spectrum antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa; whereas individual biophenols (hydroxytyrosol, luteolin, oleuropein) showed more limited activity. Molluscicidal activity was measured against Isidorella newcombi and LD(50) values were 424 ppm and 541 ppm for Mission and Frantoio extracts, respectively. The results suggest that OMW may be utilised as a source of bioactive compounds.     

Antioxidant,anti-microbial and antimutagenicity activities of pistachio (Pistachia vera) green hull extract

Antioxidant, anti-microbial and antimutagenicity activities of pistachio (Ahmadaghaei variety) green hull extracts (crude and purified extracts) were studied. At first, different solvents were compared for determining of the best solvent for extraction of phenolic compounds from pistachio green hull. Water and acetonitrile with 49.32 and 6.22 (mg of gallic acid equivalents/g sample) were the best and the worst solvent in the extraction of phenolic compounds, respectively. The antioxidant capacity of crude and purified extracts were assessed through ABTS assay, DPPH assay and β-carotene bleaching (BCB) method. A concentration-dependent antioxidative capacity was verified in ABTS, DPPH assays and BCB method. The anti-microbial capacity was screened against Gram positive and Gram negative bacteria, and fungi. Aqueous and purified extracts inhibited the growth of Gram positive bacteria; Bacillus cereus was the most susceptible one with MIC of 1 mg/mL and 0.5 mg/mL for the crude and purified extracts, respectively. The results of antimutagenicity test showed that phenolic compounds of pistachio green hull have antimutagenicity activity against direct mutagen of 2-nitrofluorene. The results obtained indicate that pistachio green hull may become important as a cheap and noticeable source of compounds with health protective potential and anti-microbial activity.     

Antioxidant and anti-neoplastic activities of Picrorhiza kurroa extracts

Picrorhizakurroa Royle ex Benth., a well-known traditional herb from the Scrophulariaceae family has a remarkable reputation among the indigenous medical practitioners. The antioxidant and anti-neoplastic activities of methanolic and aqueous extracts of P. kurroa rhizome were investigated in the present study. The total phenolic content was determined by a spectrophotometric method. The antioxidant efficacies of the extracts were studied employing radical scavenging assays (DPPH and OH), ferric reducing antioxidant property (FRAP) and thiobarbituric acid (TBA) assay for testing inhibition of lipid peroxidation. Furthermore, the cytotoxicity of the extracts was tested by XTT assay in MDA-MB-435S (human breast carcinoma), Hep3B (human hepatocellular carcinoma) and PC-3 (human prostate cancer) cell lines. The ability of the extracts to induce apoptosis was also investigated. Both extracts exhibited promising antioxidant potentials. The extracts were also observed to be cytotoxic at the tested dosage and were able to target cells towards apoptosis. The study concludes that P. kurroa possess diverse therapeutic potentials which might be useful in development of drugs or their precursors.     

Antioxidant and pro-oxidant properties of acylated pelargonidin derivatives extracted from red radish (Raphanus sativus var. niger,Brassicaceae)

The antioxidant and pro-oxidant potential of an extract from red radish, in which the major compounds were acylated pelargonidin derivatives, were assessed with a variety of assays in vitro. The extract appeared to form a complex with Fe³⁺ or Cu²⁺. It displayed a concentration-dependant reducing power (1.16 OD_{700 nm} at a concentration of 4 mM) and scavenging effect against 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals (with IC₅₀ = 1.74 ± 0.03 mM). It could promote the cleavage of plasmid DNA with Cu(II)/H₂O₂ or Cu(II) alone. This DNA damage could be inhibited by horseradish peroxidase, catalase, and EDTA, respectively. The extract also showed growth inhibition of Bel-7402 cells at lower concentration. The results suggested that the formation of reactive oxygen species might be involved in the mechanism of DNA damage. The acylated pelargonidin derivatives extracted from red radish could act as antioxidant and pro-oxidant and their antioxidant and pro-oxidant properties were relative to the reaction conditions. It might provide novel antioxidant and anticarcinogenic agents.     

Anti-inflammatory activity of Korean thistle Cirsium maackii and its major flavonoid,luteolin 5-O-glucoside

The anti-inflammatory activity of whole Cirsium maackii (family Compositae) plants and of its major flavonoid, luteolin 5-O-glucoside, was evaluated for their ability to inhibit lipopolysaccharide (LPS)-induced nitric oxide (NO) production, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) protein expression, and tert-butylhydroperoxide (t-BHP)-induced reactive oxygen species (ROS) generation in RAW 264.7 murine macrophage cells. The methanolic extract of C. maackii showed strong anti-inflammatory activity, and was thus fractionated with several solvents. The ethyl acetate-soluble fraction, exhibiting the highest anti-inflammatory activity potential, was further to yield a major flavonoid, luteolin 5-O-glucoside. We found that luteolin 5-O-glucoside, at a non-toxic concentration, inhibited LPS-induced NO production and t-BHP-induced ROS generation in a dose-dependent manner in RAW 264.7 cells. It also suppressed the expression of iNOS and COX-2 in LPS-stimulated macrophages. Furthermore, the efficacies of the methanolic extract of C. maackii in inhibiting both NO and ROS were attributed to its flavonoid content by HPLC analysis. These results indicated that C. maackii whole plants and its flavonoids inhibit the expression of iNOS and COX-2 in through the inhibition of ROS generation, and therefore can be considered as a useful therapeutic and preventive approach for the treatment of various inflammatory and oxidative stress-related diseases.     

The methanolic fraction of Centratherum anthelminticum seed downregulates pro-inflammatory cytokines,oxidative stress,and hyperglycemia in STZ-nicotinamide-induced type 2 diabetic rats

This study aimed to ascertain the potential of Centratherum anthelminticum seeds methanolic fraction (CAMFs) for the management of type 2 diabetes and its associated complications. CAMFs was initially tested on β-TC6 cells for H₂O₂-induced nuclear factor-κB (NF-κB) translocation effects. The result displayed that CAMFs significantly inhibited NF-κB translocation from cytoplasm into the nucleus, dose-dependently. Furthermore, a 12-week sub-chronic CAMFs study was carried out on streptozotocin (STZ)-nicotinamide–induced type 2 diabetic rat model to evaluate glycemia, essential biochemical parameters, lipid levels, oxidative stress markers, and pro-inflammatory cytokines level. Our study result showed that CAMFs reduced hyperglycemia by increasing serum insulin, C-peptide, total protein, and albumin levels, significantly. Whereas, elevated blood glucose, glycated hemoglobin, lipids and enzyme activities were restored to near normal. CAMFs confirmed antioxidant potential by elevating glutathione (GSH) and reducing malondialdehyde (MDA) levels in diabetic rats. Interestingly, CAMFs down-regulated elevated tumor necrosis factor α (TNF-α), interleukin (IL)-1β and IL-6 in the tissues and serum of the diabetic rats. We conclude that CAMFs exerted apparent antidiabetic effects and demonstrated as a valuable candidate nutraceutical for insulin-resistant type 2 diabetes and its associated complications such as dyslipidemia, oxidative stress, and inflammation.     

Medicinal properties of mangosteen (Garcinia mangostana)

Many tropical plants have interesting biological activities with potential therapeutic applications. Garcinia mangostana Linn. (GML) belongs to the family of Guttiferae and is named “the queen of fruits”. It is cultivated in the tropical rainforest of some Southeast Asian nations like Indonesia, Malaysia, Sri Lanka, Philippines, and Thailand. People in these countries have used the pericarp (peel, rind, hull or ripe) of GML as a traditional medicine for the treatment of abdominal pain, diarrhea, dysentery, infected wound, suppuration, and chronic ulcer.