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Carvacrol (5-isopropyl-2-methyl phenol) is a natural compound that occurs in the leaves of a number of plants and herbs including wild bergamot, thyme and pepperwort, but which is most abundant in oregano. The aim of this review is to analyse the scientific data from the last five years (2012-2017) on the antimicrobial and anti-biofilm activities of carvacrol, targeting different bacteria and fungi responsible for human infectious diseases. The antimicrobial and anti-biofilm mechanisms of carvacrol and its synergies with antibiotics are illustrated. The potential of carvacrol-loaded anti-infective nanomaterials is underlined. Carvacrol shows excellent antimicrobial and anti-biofilm activities, and is a very interesting bioactive compound against fungi and a wide range of Gram-positive and Gram-negative bacteria, and being active against both planktonic and sessile human pathogens. Moreover, carvacrol lends itself to being combined with nanomaterials, thus providing an opportunity for preventing biofilm-associated infections by new bio-inspired, anti-infective materials.

Objectives: Depression is one of the most common psychiatric disorders, and the fourth leading cause of long-term disability throughout the world. Despite the availability of different classes of antidepressant drugs, most of them are not completely effective and above all are associated with many serious adverse effects. Recently, accumulating evidence suggests that dietary supplements rich in important phytochemicals possess beneficial therapeutic roles in depression., Methods: In this review, we will first consider what is known about the pathogenesis of depression and discuss the need for more safe and efficacious treatment. We will then review the potential clinical relevance of natural plant-derived products based on data derived from pre-clinical animal studies, randomized controlled studies and placebo-controlled trials published on this topic within the last decade., Results: Among the natural compounds that show antidepressive-like activity, green tea catechins have been shown to decrease depressive symptoms in experimental animals, possibly in part through the inhibition of monoamine oxidase (MAO). Anthocyanins and their aglycons, responsible for the typical color of berries, inhibit MAO isoforms A or B with IC50 values corresponding to the micromolar range. Other studies suggest that cocoa extracts, whose main components are procyanidins, attenuate depressive symptoms in rats. Resveratrol, one of the most important natural stilbenoid, inhibits noradrenaline and serotonin reuptake in rats, and significantly decreases anxiety/depressive behaviours while increasing hippocampal serotonin and noradrenaline levels. Trans-resveratrol possesses MAO-A inhibitory effects in different brain areas, particularly in the frontal cortex and hippocampus, as already reported for tea catechins. Although these effects have been documented in rodent models, further randomized controlled trials in this area are warranted. However, so far, there is only correlative evidence between certain nutrients, such as omega-3 polyunsaturated fatty acids and B vitamins, and depression in human population studies., Discussion: Growing evidence suggests that consumption of these compounds may represent an alternative strategy to delay the onset and progression of depression, and depressive-like symptoms. However, further randomized and placebo-controlled trials are necessary to confirm the potential of these compounds as a possible remedy for this debilitating disorder.

Context: In Iranian traditional medicine, different species of the genus Tetrataenium are used as antiseptic, spice and food additives., Objective: The present study examined the possible antioxidant effects of hydro-alcoholic extracts of different parts of Tetrataenium lasiopetalum (Boiss.) Manden (Apiaceae)., Materials and Methods: Laminas, stems, petioles, fruits, peduncles and flowers of T. lasiopetalum were collected, dried and then extracted by ethanol and water (70:30). Antioxidant activities of extracts were examined by employing different in vitro assays, i.e., 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, metal chelating, reducing power activities and hemoglobin-induced linoleic acid system. Also, total phenolic and flavonoid contents of the extracts were evaluated., Results: Hydro-alcoholic extract of T. lasiopetalum flower showed the highest activity in scavenging of DPPH (IC50 = 170 ± 7 μg/mL). In metal chelating assay, lamina extract possesses a better iron ion chelating activity than other extracts (230 ± 10 μg/mL). Lamina hydro-alcoholic extract demonstrated better activity in reducing the power and hemoglobin-induced linoleic acid system than other parts of T. lasiopetalum., Discussion and Conclusion: These results showed the antioxidant activity of different parts of T. lasiopetalum based on its usage in traditional medicine.

Context: Quercetin is a well known aglycone flavonoid that is widely found in different food sources., Objective: In this study, the in vivo neuroprotective potential of quercetin against sodium fluoride-induced oxidative stress was evaluated., Materials and Methods: Wistar rats were divided into five treatment groups and then subjected to daily intraperitoneally treatment with quercetin (at 10 and 20 mg/kg body weight), vitamin C (at 10 mg/kg), or vehicle. After a 1 week treatment period, all groups except saline treated (normal group), were intoxicated with sodium fluoride (NaF) for 1 week. Rat brains were then removed and homogenized for measurement of antioxidant markers including superoxide dismutase (SOD), reduced glutathione, catalase, and lipid peroxidation final products., Results: The thiobarbituric acid reactive substances (TBARS) levels in the heart homogenate of sodium fluoride treated rats (42.04 ± 2.14 nmol MDA eq/g tissue) increased compared to the normal rats (35.99 ± 1.08 nmol MDA eq/g tissue). Animals which were pretreated with quercetin at 20 mg/kg for 1 week prior to sodium fluoride intoxication showed significant reduction in the TBARS level (36.13 ± 1.12 nmol MDA eq/g tissue). Also, pretreatment with quercetin (20 mg/kg) restored the SOD and catalase activities and modified the level of reduced glutathione compared with the control group (p > 0.05)., Discussion and Conclusion: The present study revealed a potent neuroprotective potential of quercetin against NaF-induced toxicity.

Context: The genus Primula (Primulaceae) has been used in traditional medicine to treat convulsion and microbial or viral infections., Objective: In the present study, we evaluate antioxidant, antihemolytic, and protective effects of flavonoid-rich fractions of endemic Primula heterochroma Stapf. (Primulaceae) against Fe(2+)-induced lipid peroxidation and oxidative stress in rat brain in vitro., Materials and Methods: Aerial parts of plant were defatted and extracted with 60% acetone. Then, 60% acetone extract was fractionated sequentially with n-hexane, ethyl acetate, and water. Antioxidant activity of fractions was evaluated by employing six different assays, i.e., 1,1-diphenyl-2-picryl hydrazyl (DPPH) and hydrogen peroxide scavenging, metal chelating and reducing power activities and hemoglobin-induced linoleic acid system and Fe(2+)-induced lipid peroxidation and oxidative stress in rat brain. Also, its antihemolytic activity was determined using 2,2'-azobis(2-amidinopropane) dihydrochloride-induced hemolysis in rat erythrocyts., Results: Among the flavonoid-rich fractions of Primula heterochroma, aqueous fraction demonstrated the most protective effect through decreasing brain thiobarbituric acid reactive substances (TBARS) levels at a dose 200 μg mL(-1) (40%, p < 0.001 versus iron group). Also, the aqueous fraction showed better activity in Fe(2+) chelating (89 ± 3.8 μg mL(-1)) and DPPH radical scavenging (394.4 ± 18.4 μg mL(-1)) models than other fractions. The probable protective mechanism of flavonoid-rich fractions may be attributed to their Fe(2+) chelating, DPPH radical scavenging and reducing power activities. Also, the n-hexane fraction demonstrated a higher protective effect in the hemoglobin-induced linoleic acid system and 2,2'-azobis(2-amidinopropane) dihydrochloride-induced hemolysis (67 ± 2.6 μg mL(-1))., Discussion and Conclusion: Results of this study demonstrate Primula heterochroma is a rich source of natural antioxidant compounds.

Context: Hyssopus angustifolius M. Bieb. (Lamiaceae) is one of the most important medicinal plants in Iranian traditional medicine for the treatment of lung inflammation, laryngitis and cough relief. Much attention has been paid to this medicinal plant because of its traditional uses., Objective: The present study examined the antioxidant and antihemolytic activities of ethyl acetate extract of stems, leaf and flowers of Hyssopus angustifolius., Materials and Methods: Antioxidant activity of extracts was evaluated by employing six different models, i.e., DPPH, nitric oxide and hydrogen peroxide scavenging, metal chelating and reducing power activities and hemoglobin-induced linoleic acid system. Also, antihemolytic activity was evaluated against hydrogen peroxide-induced hemolysis., Results: Flowers extract showed the better activity than leaf and stems extracts in DPPH radical scavenging activity (IC₅₀ was 275.4 ± 7.6 μg mL⁻¹). Leaf, stems and flowers extracts showed good nitric oxide scavenging activity (IC₅₀ were 376.6 ± 11.4 µg mL⁻¹ for flowers, 297.6 ± 9.6 μg mL⁻¹ µg mL⁻¹ for leaves and 837.8 ± 19.2 µg mL⁻¹ for stems). The leaf extract exhibited better hydrogen peroxide scavenging and Fe²⁺ chelating activity than stems and flowers extracts. In hemoglobin-induced linoleic acid system, all of the extracts exhibited very good activity. Also, extracts show weak reducing power activity. The ethyl acetate extract of leaf showed better antihemolytic activity than the flower and stems (IC₅₀ was 94.0 ± 2.4 μg mL⁻¹)., Discussion and Conclusion: These findings give a scientific basis to the traditional usage of Hyssopus angustifolius, also showing its potential as rich sources of natural antioxidant compounds.