Antioxidant activity of yellow dock (Rumex crispus L., Polygonaceae) fruit extract

The methanol extract of ripe Rumex crispus L. fruits was evaluated for its antioxidant potential by assays for ferric‐reducing antioxidant power (FRAP), DPPH‐free radical scavenging activity (DPPH) and the influence on lipid peroxidation in liposomes (LP). Considerable activity was observed in all test systems (FRAP: 9.9 mmol Fe²⁺/g; DPPH IC₅₀: 3.7 μg/mL; LP IC₅₀: 4.9 μg/mL), comparable to that of BHT (FRAP: 8.0 μg/mL; DPPH IC₅₀: 19.4 μg/mL; LP IC₅₀: 3.5 μg/mL), but lower than the activity of ascorbic acid, rutin and quercetin, used as positive control substances. The in vivo effects were evaluated in several hepatic antioxidant systems (activities of LPx, GSH‐Px, Px, CAT and XOD, as well as GSH content), after treatment with the studied yellow dock extract in different doses, or in combination with carbon tetrachloride (CCl₄). Pretreatment with the R. crispus extract inhibited CCl₄‐induced oxidative stress by decreasing LPx and increasing GSH content in a dose dependent manner, bringing the levels of antioxidant enzymes to near control values. Copyright © 2010 John Wiley & Sons, Ltd.     

Antiviral activity of chilean medicinal plant extracts

Chilean flora is a potential source of bioactive compounds, including some with antiviral activity. Ninety aqueous and hydroaloholic extracts from 36 native and introduced plant species were screened for antiviral activity on herpes (HSV-1 and HSV-2) and HIV viruses. Furthermore, the samples were assayed for antimicrobial effect on pathogenic bacteria and a yeast. Plants were selected according to their indication of use for treating symptomatology of possible viral aetiology in Chilean folk medicine. The hydroaloholic extracts of Cassia stipulacea and Escallonia illintia exhibited detectable antiviral effects towards HSV-1 with IC₅₀ values of 80 and 40 μg crude extract/mL, respectively. Samples belonging to Aristotelia chilensis (IC₅₀ of 40 μg/mL), Drymis winteri (IC₅₀ values of 35 and 80μg/mL), Elytropus chilensis and Luma apiculata, with an IC₅₀ value of 100 μg/mL showed activity against HSV-2. None of the extracts showed activity against HIV at extract concentrations which were nontoxic for cells.     

Compounds with tyrosinase inhibition, elastase inhibition and DPPH radical scavenging activities from the branches of Distylium racemosum Sieb. et Zucc

Twenty compounds were isolated from the ethanol extract of Distylium racemosum branches and their inhibitory activities on tyrosinase, elastase and free radicals evaluated. The isolated compounds were identified as dibenzofurans (1–4), abscisic acid (5), 6′‐O‐galloylsalidroside (6), catechin derivatives (7–11), gallic acid derivatives (12–14), tyrosol (15), flavonoids (16–18), lupeol (19) and 1,2,3,6‐tetragalloylglucose (20). For study of tyrosinase inhibition activities, when compared with arbutin (IC₅₀ 48.8 μg/mL), four compounds (8, 11, 13, 17) showed higher activities, with IC₅₀ values of 4.8, 30.2, 40.5 and 37.7 μg/mL, respectively. For the elastase inhibition test, dibenzofuran 1 showed greater activity than the positive control, oleanolic acid (IC₅₀ 9.7 μg/mL), with an IC₅₀ of 7.7 μg/mL. In the studies on DPPH radical scavenging activities, five compounds (11, 12, 13, 14, 15) showed higher activities than ascorbic acid (IC₅₀ 5.0 μg/mL), with IC₅₀ values of 4.6, 3.9, 2.9, 3.8 and 4.7 μg/mL, respectively. Copyright © 2011 John Wiley & Sons, Ltd.     

Extracts of Bolivian plants,Copaifera reticulata and Heisteria pallida inhibit in vitro free radical-mediated DNA damage

The presence of different extracts of antiinflammatory plants Copaifera reticulata and Heisteria pallida in a reaction medium containing calf thymus DNA in a free radical generating system protected DNA against oxidative damage in terms of deoxyribose oxidation. The highest antioxidant activity was obtained using the methanol extract of C. reticulata (IC₅₀=3 μg/mL), followed by the aqueous extracts of H. pallida (IC₅₀=257 μg/mL) and C. reticulata (IC₅₀=380 μg/mL). Both dichloromethane extracts and the methanol extract of H. pallida showed a decreased antioxidant activity at higher concentrations. These results suggest that these extracts are capable of suppressing the in vitro oxidative degradation of DNA. © 1997 John Wiley & Sons, Ltd.     

Cyclooxygenase‐2 inhibitory and antioxidant compounds from the truffle Elaphomyces granulatus

The ethanol extract of fruiting bodies of Elaphomyces granulatus, a truffle‐like fungus, was evaluated for cyclooxygenase‐2 (COX‐2) enzyme inhibitory and antioxidant activities. Inhibition of COX‐2 activity was evaluated in mouse macrophages (RAW 264.7). The extract of E. granulatus caused a 68% inhibition of COX‐2 activity at 50 µg/mL. Bioassay‐guided investigation led to the isolation and identification of two active compounds, syringaldehyde and syringic acid. Syringaldehyde moderately inhibited COX‐2 activity with an IC₅₀ of 3.5 µg/mL, while syringic acid strongly inhibited COX‐2 activity with an IC₅₀ of 0.4 µg/mL. The antioxidant activity of the extract and isolated compounds was evaluated in HL‐60 cells by the DCFH‐DA method. The extract of E. granulatus showed a potent antioxidant effect, with an IC₅₀ of 41 µg/mL. Of the pure compounds, syringic acid displayed a strong antioxidant activity, with an IC₅₀ of 0.7 µg/mL, while syringaldehyde showed no activity in the assay. Copyright © 2008 John Wiley & Sons, Ltd.     

Selective modulatory effects of the essential oil of Croton zehntneri on isolated smooth muscle preparations of the guinea-pig

The effects of the essential oil of the plant Croton zehntneri (EOCz) in the concentration range 1–200 μg/mL were studied on the mechanical activity of various in vitro smooth muscle preparations of the guinea-pig. In isolated ileum EOCz induced a variable response such that in 57% of tissues basal tone was reduced (EC₅₀ 5 μg/mL) whereas the rest remained unaffected by the oil. In concentrations above 10 μg/mL EOCz induced spontaneous oscillatory contractions in all preparations. In contrast the basal tone of the aorta, portal vein and bladder remained unaltered by the oil. In the portal vein EOCz concentration-dependently inhibited the amplitude of spontaneous contractions (IC₅₀ 109 μg/mL) without reducing frequency, whereas in the bladder such activity was increased by the oil (EC₅₀ 44 μg/mL). In ileum precontracted with 60 mM KCl, EOCz induced a complete and concentration-dependent relaxation with an IC₅₀ value of approximately 26 μg/mL. In contrast EOCz did not relax KCl-induced tone in the aorta or bladder, whilst eliciting less than 20% relaxation of the precontracted portal vein. Thus our data show that EOCz exerts differential modulatory effects on the contractility of various smooth muscles of the guinea-pig. That EOCz appears to selectively relax intestinal smooth muscle may support its use in folk medicine as a gastrointestinal antispasmodic. © 1998 John Wiley & Sons, Ltd.     

In Vitro activities of plant extracts from Saudi Arabia against malaria,leishmaniasis, sleeping sickness and Chagas disease

The in vitro activity of the methanol extracts of 51 plants randomly collected from the Kingdom of Saudi Arabia and some of their fractions (petroleum ether, chloroform, ethyl acetate and aqueous) were evaluated against Plasmodium falciparum, Trypanosoma brucei brucei, T. cruzi and Leishmania infantum, as well as toxicity against MRC‐5 fibroblast cells. Ten crude methanolic extracts that demonstrated potent and adequately selective antiprotozoal activity were subjected to solvent fractionation using petroleum ether, ethyl acetate and chloroform. Only three samples showed promising antiprotozoal activity. Argemone ochroleuca (CHCl₃ fraction) showed pronounced activity against P. falciparum_GHA (IC₅₀ 0.32 μg/mL) and T. cruzi (IC₅₀ 0.30 μg/mL) with low cytotoxicity against MRC‐5 cells (CC₅₀ 11.6 μg/mL). Capparis spinosa (EtOAc fraction) showed pronounced activity against P. falciparum_GHA with an IC₅₀ 0.50 μg/mL in the absence of toxicity against MRC‐5 cell line (CC₅₀ > 30 μg/mL). Heliotropium curassavicum (CHCl₃ fraction) showed similar activity against P. falciparum (IC₅₀ 0.65 μg/mL; MRC‐5 CC₅₀ > 30 μg /mL). These three extracts will be subjected for further extensive studies to isolate and identify their active constituents. Copyright © 2010 John Wiley & Sons, Ltd.     

Evaluation of Turkish seaweeds for antiprotozoal, antimycobacterial and cytotoxic activities

As part of our continuing research on seaweeds, crude MeOH extracts of two green, three brown and six red algae collected from Marmara, Black, Aegean and Mediterranean Seas were screened. Four parasitic protozoa, i.e. Plasmodium falciparum, Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani and the tubercle bacillus Mycobacterium tuberculosis were used as test organisms for the in vitro assays. The selective toxicity of the extracts was also determined against mammalian L6 cells. All seaweed extracts were active against T. brucei rhodesiense; the Dasya pedicellata extract was the most potent (IC₅₀ value 0.37 µg/mL). The same extract also weakly inhibited the growth of T. cruzi (IC₅₀ 62.02 µg/mL). All seaweed extracts also showed leishmanicidal activity (IC₅₀ values 16.76–69.98 µg/mL). The majority of the extracts also exhibited antiplasmodial potential and the most potent extracts were those from D. pedicellata (IC₅₀ 0.38 µg/mL), Codium bursa (IC₅₀ 1.38 µg/mL) and Caulerpa rasemosa (IC₅₀ 3.12 µg/mL). One brown and two red algal extracts showed some weak activity against Mycobacterium tuberculosis (MIC values 125–256 µg/mL). Except for the extract of Dasya pedicellata, none of the extracts displayed any cytotoxicity. This is the second study investigating the antiprotozoal activities of Turkish marine algae and identifies Dasya pedicellata, an understudied algal species, as a candidate for further studies. Copyright © 2010 John Wiley & Sons, Ltd.     

Antiviral activity of daphnoretin isolated from Wikstroemia indica

The ethanol extract of Wikstroemia indica was fractionated with organic solvents of different polarities, and various fractions were screened for their antiviral activity against respiratory syncytial virus (RSV) using a cytopathic effect (CPE) reduction assay. The ethyl acetate fraction was most active against RSV with 50% inhibition concentration (IC₅₀) value < 3.9 μg/mL and a selectivity index (SI) > 64.1. Further isolation and purification of the fraction led to a purified compound, daphnoretin. Daphnoretin was tested for its anti‐RSV activity using a plaque reduction assay and found active against RSV, with an IC₅₀ value of 5.87 μg/mL and SI value of 28.17. The mode of antiviral action study revealed that daphnoretin could slightly inhibit the early events of the viral infection but its effect was mainly on the later phase of the replication cycle. Copyright © 2009 John Wiley & Sons, Ltd.     

The Traditional Medicine Spilanthes acmella,and the Alkylamides Spilanthol and Undeca‐2E‐ene‐8,10‐diynoic Acid Isobutylamide,Demonstrate In Vitro and In Vivo Antimalarial Activity

Spilanthes spp. are used as traditional herbal medicines in Africa and India to treat malaria. Yet, to date, there are no data on the active constituents or the most effective extraction methods for this indication. The isolated alkylamides, spilanthol and undeca‐2E‐ene‐8,10‐diynoic acid isobutylamide, found in S. acmella Murr., were shown to have IC₅₀s of 16.5 μg/mL and 41.4 μg/mL on Plasmodium falciparum strain PFB and IC₅₀s of 5.8 μg/mL and 16.3 μg/mL for the chloroquine resistant P. falciparum K1 strain, respectively. Further investigations revealed that at relatively low concentrations, spilanthol and the water extract of S. acmella reduced the parasitemia 59% and 53% in mice infected with P. yoelii yoelii 17XNL at 5 mg/kg and 50 mg/kg, respectively. Unexpectedly, the 95% ethanol extract of S. acmella was less effective (36% reduction in parasitemia) at 50 mg/kg. These results provide the first evidence supporting S. acmella against malaria and demonstrating active constituents in S. acmella against P. falciparum. Copyright © 2011 John Wiley & Sons, Ltd.     

Evaluation of pharmacological activity of a crude hydroalcoholic extract from Jatropha elliptica

The pharmacological effect of the hydroalcoholic extract of Jatropha elliptica was analysed in in vivo and in vitro models. When given orally in mice, the extract showed a low acute toxicity (LD₅₀ 5 g/kg). In a dose of 0.5 or 1 g/kg p.o. the extract did not interfere with diuresis in the rat, but was found to be effective in blocking rat paw oedema induced by carrageenan and partially, serotonin-induced oedema. In the same dose, the extract failed to inhibit rat paw oedema induced by dextran and the increase of rat cutaneous vascular permeability caused by Bothrops Jararaca venom, dextran, histamine, PAF-acether and serotonin. Pre-incubation of the isolated rat uterus and guinea-pig ileum with the extract (0.2–0.8 mg/mL), produced a concentration-related and non-competitive inhibition of contractions induced by acetylcholine and bradykinin. However, the extract was about 2-fold more potent in inhibiting the contraction of both agonists in guinea-pig ileum than in rat uterine muscle. In rat aorta, the extract (50–100 μg/mL) caused a concentration-dependent inhibition of noradrenaline-evoked contractions, being about 5-fold more potent when compared to the IC₅₀ values obtained in rat uterus.     

The Immunosuppressive Effects of Globularia alypum Extracts

Responder lymphocytes were cultured with an equal number of irradiated stimulator lymphocytes from another donor for 6 days in RPMI 1640 (a modified Mc Coh's 5 A Medium). After 48 h incubation with PMA (phorbol 12-myristate), PHA (phytohaematogglutin) and 120 h with MLR (mixed lymphocytes reaction), the cells were labelled with ³H-thymidine. Cells were harvested in a scintillation counter Globularia alypum L. extracts were dissolved in HPLC quality ethanol or water and diluted in RPMI to concentrations ranging from 0.156–10 μg/mL. Extract solutions were added immediately after cell stimulation in the cell walls. Cyclosporin A was used as a control. Both the water and ethanol extracts of Globularia alypum L. demonstrated a dose response effect in all three systems of MLR, PHA and PMA with no statistical difference in water or ethanol extracts. The IC₅₀ were: PHA 1.14 μg/mL, PMA 1.05 μg/mL and MLR 2.06 μg/mL. The PHA and MLR IC₅₀ are approximately double the IC₅₀ for cyclosporin A (0.5 μg/mL). The effects of Glubularia alypum L. in PMA stimulated lymphocytes suggests it may suppress T cell function through a pathway that cyclosporin A does not effect.     

Screening of some Tanzanian medicinal plants for their trypanocidal and cytotoxic activities

The objective of the present study was to evaluate in vitro antitrypanosomal and cytotoxic activities of crude extracts of 20 traditionally used medicinal plants of Tanzania. A total of 40 extracts (dichloromethane and methanol) were screened for antiproliferative activity of bloodstream form of T. b. brucei and human leukaemia HL‐60 cell. Inhibition of cell proliferation was assessed using resazurin as vital stain. Of the 40 extracts tested, the dichloromethane extract from bark of Warburgia salutaris (Canellaceae) exhibited the most potent antitrypanosomal activity with an IC₅₀ value of 10.68 μg/ml. A dichloromethane extract from Lannea stuhlmannii (Anacardiaceae) was found to be the most cytotoxic extract against HL‐60 (IC₅₀ = 27.15 μg/ml). Out of the 20 plants tested, 5 plants exhibited trypanocidal activity with IC₅₀ values below 20 μg/ml. These 5 plants: Entandrophragma bussei (Meliaceae), Securidaca longepedunculata (Polygalaceae), Warburgia salutaris (Canellaceae), Zanha africana (Sapindaceae) and Zanthoxylum chalybeum (Rutaceae) could therefore serve as sources of lead compounds for treatment of trypanosomiasis. Copyright © 2009 John Wiley & Sons, Ltd.     

Preliminary studies on the hydroalcoholic extract of the root of Cissampelos sympodialis Eichl in guinea-pig tracheal strips and bronchoalveolar leucocytes

The aqueous fraction of the ethanol extract of the root of Cissampelos sympodialis, reduced the spontaneous tone, and inhibited the contractions induced by submaximal concentrations of carbachol, histamine, prostaglandin F_2α and substance P, in guinea-pig tracheal preparations. The fraction was approximately equipotent to aminophyl-line and the IC₅₀ values of the above agents varied from 13.9 to 95.5 μg/mL, depending on the agonist used. In concentrations ranging from 1–100 μg/mL, the fraction also increased the intracellular levels of cyclic adenosine monophosphate in guinea-pig bronchoalveolar leucocytes. It is proposed that the combined effects on smooth muscles and on leucocytes indicate a pharmacological basis for the use of the plant in asthma.     

Inhibition of keratinocyte growth by different Nepalese Zanthoxylum species

A total of 11 methanol extracts obtained from four different Nepalese Zanthoxylum species were screened for their antiproliferative activity against the growth of human keratinocytes (HaCaT cells). The extract obtained from Z. armatum barks was highly active with an IC₅₀ value of 11 µg/mL. Also, the extracts ­obtained from Z. oxyphyllum barks and roots with IC₅₀ values of 53 and 57 µg/mL, respectively, showed potent activity. Their antiproliferative activity was not due to cytotoxic effects on cell membranes, as documented by the activity of lactate dehydrogenase released from the cytoplasm of keratinocytes, which did not exceed that of the control value. Rather, they also protected against radical‐induced ­damage to model membranes stimulated with 2,2′‐azo‐bis(2‐amidinopropane) dihydrochloride. Copyright © 1999 John Wiley & Sons, Ltd.     

Antihyperlipidemic Components of Cassia auriculata Aerial Parts: Identification Through In Vitro Studies

Cassia auriculata (Caesalpiniaceae) is a common Asian beverage and medicinal plant widely used in tradition medicine for diabetes, hyperlipidemia and various other disease conditions. Previous studies on crude extracts of C. auriculata have documented the scientific basis for some of its traditional medicinal uses. The present study investigates the antilipase activity of the ethanol extract of the aerial parts along with the previously isolated compounds (kaempferol‐3‐O‐rutinoside, rutin, kaempferol, quercetin and luteolin). The crude extract displayed inhibitory activity against pancreatic lipase with IC₅₀ of 6.0 ± 1.0 µg/mL. The most active antilipase compound was kaempferol‐3‐O‐rutinoside with IC₅₀ value (2.9 ± 0.50 μM) only about twice weaker than the standard antilipase drug, orlistat (IC₅₀ = 1.45 ± 0.26 μM). Luteolin, quercetin and rutin were found to be weak pancreatic lipase inhibitors (IC₅₀ over 100 μM), whereas kaempferol showed no activity up to 250 μM. The antihyperlipidemic effect of C. auriculata could be attributed to direct lipase inhibitory effect of the plant constituents. Copyright © 2012 John Wiley & Sons, Ltd.     

Antiviral activity in vitro of Cupressus sempervirens on two human retroviruses HIV and HTLV

A proanthocyanidin polymer fraction (MW 1500–2000 daltons) from Cupressus sempervirens L. (Cupressaceae) exhibited true antiviral activity in vitro against two retroviruses, HIV and HTLV III B. In comparison with AZT no toxicity was observed with PPC at concentrations of 50 μg/mL which exceeded the IC₅₀ values (1.5 to 15 μg/mL for HIV and 5 to 25 μg/mL for HTLV). © 1998 John Wiley & Sons, Ltd.     

Screening of medicinal plants from Iranian traditional medicine for acetylcholinesterase inhibition

To find new herbal compounds with an acetylcholinesterase (AChE) inhibitory effect, this study focused on herbal drugs and resins which have been used in Iranian traditional medicine for the treatment of cognitive disorders. Forty drugs were selected from authoritative written documents of Iranian traditional medicine. Each drug was extracted by accelerated solvent extraction using dichloromethane followed by methanol. The 80 extracts were screened for AChE inhibitory activity by a TLC bioautography method. The inhibiting effect of the 32 most active extracts was measured by a microplate colorimetric assay. Due to the best activity, the seeds of Peganum harmala L. were investigated in detail. From the TLC bioautography assay the alkaloids harmaline and harmine were identified as active compounds. This result was confirmed by means of HPLC‐DAD. The IC₅₀ values were 41.2 μg/mL for the methanol extract, 95.5 μg/mL for the dichloromethane extract, 8.4 μg/mL for harmaline and 10.9 μg/mL for harmine. The concentrations of active compounds in the extracts were determined by a fast and precise HPLC method. As the amounts of harmaline and harmine in the extracts were correlated with the IC₅₀ values of the extracts, it can be concluded that these two alkaloids are responsible for the AChE inhibitory activity of P. harmala. Copyright © 2011 John Wiley & Sons, Ltd.     

Antiprotozoal,antimycobacterial and cytotoxic potential of twenty‐three British and Irish red algae

As part of our continuing research on seaweeds, we have screened the crude extracts of 23 red marine algae collected from England and Ireland. The clinically important blood‐stage life forms of Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani and Mycobacterium tuberculosis were used as test organisms in the in vitro assays. The selectivity of the extracts was determined by using mammalian skeletal myoblast (L6) cells. All algal extracts showed activity against T. brucei rhodesiense, with Corallina officinalis and Ceramium virgatum being the most potent (IC₅₀ values 4.8 and 5.4 μg/ml), whilst none of the algal extracts inhibited the growth of T. cruzi. Except for Porphyra leucosticta, extracts from all seaweeds also showed leishmanicidal activity with IC₅₀ values ranging from 16.5 to 85.6 μg/ml. Only the crude extract of Calliblepharis jubata showed some weak activity against Mycobacterium tuberculosis (MIC value 256 μg/ml), while the others were inactive at this concentration. Corallina officinalis was the only seaweed that displayed some marginal cytotoxicity (IC₅₀ value 88.6 μg/ml), and all remaining extracts were non‐toxic towards L6 cells at 90 μg/ml concentration. To our knowledge, this is the first study reporting antiprotozoal and antimycobacterial activity of British and Irish red algae. Copyright © 2010 John Wiley & Sons, Ltd.     

Antiparasitic activity of C-geranyl flavonoids from Mimulus bigelovii

Bioactivity‐directed fractionation of the MeOH fraction of the extract of Mimulus bigelovii by means of an axenic Leishmania amastigote assay and chromatographic techniques resulted in the isolation of four C‐geranyl flavanones, diplacone (1), 3′‐O‐methyldiplacone (2), 4′‐O‐methyldiplacone (3), 3′‐O‐methyldiplacol (4), together with a geranylated flavone, cannflavin A (5). These compounds were separated from M. bigelovii for the first time. All compounds showed moderate antileishmanial activity against axenic Leishmania donovani amastigotes with IC₅₀ values ranging from 4.8 to 14.6 μg/mL. The compounds were also tested against the related kinetoplastid parasite Trypanosoma brucei brucei and they showed activity with IC₅₀ values ranging from 1.4 to 7.2 μg/mL. Copyright © 2011 John Wiley & Sons, Ltd.