Antitumor and antiviral activity of Colombian medicinal plant extracts.

Extracts of nine species of plants traditionally used in Colombia for the treatment of a variety of diseases were tested in vitro for their potential antitumor (cytotoxicity) and antiherpetic activity. MTT (Tetrazolium blue) and Neutral Red colorimetric assays were used to evaluate the reduction of viability of cell cultures in presence and absence of the extracts. MTT was also used to evaluate the effects of the extracts on the lytic activity of herpes simplex virus type 2 (HSV-2). The 50% cytotoxic concentration (CC50) and the 50% inhibitory concentration of the viral effect (EC50) for each extract were calculated by linear regression analysis. Extracts from Annona muricata, A. cherimolia and Rollinia membranacea, known for their cytotoxicity were used as positive controls. Likewise, acyclovir and heparin were used as positive controls of antiherpetic activity. Methanolic extract from Annona sp. on HEp-2 cells presented a CC50 value at 72 hr of 49.6x10(3)mg/ml. Neither of the other extracts examined showed a significant cytotoxicity. The aqueous extract from Beta vulgaris, the ethanol extract from Callisia grasilis and the methanol extract Annona sp. showed some antiherpetic activity with acceptable therapeutic indexes (the ratio of CC50 to EC50). These species are good candidates for further activity-monitored fractionation to identify active principles.     

Phytomedicinal potential of tropical cloudforest plants from Monteverde, Costa Rica

A pharmacological survey of plants from Monteverde, Costa Rica, including 165 species representing 61 families has been carried out. Crude plant extracts have been tested for in-vitro bactericidal and fungicidal activity as well as cytotoxic and anti-herpes activity. Of these, 123 extracts exhibited notable cytotoxicity, 62 showed antibacterial activity, 4 showed antifungal activity, and 8 showed promising antiviral activity. Thus, 101 of the plant species examined in this work, or 62%, showed marked bioactivity in one or more bioassays. These results underscore the phytomedicinal potential of Neotropical cloud forests.     

Antioxidant, radical-scavenging, anti-inflammatory, cytotoxic and antibacterial activities of methanolic extracts of some Hedyotis species

The antioxidant, radical-scavenging, anti-inflammatory, cytotoxic and antibacterial activities of methanolic extracts of seven Hedyotisspecies were investigated. The antioxidant activity was evaluated by the ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods while the radical scavenging activity was measured by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. The anti-inflammatory activity related to NO inhibition of the plant extracts was measured by the Griess assay while cytotoxicity were measured by the MTT assay against CEM-SS cell line. The antibacterial bioassay (against 4 bacteria, i.e. Bacillus subtilis B28 (mutant), Bacillus subtilis B29 (wild-type), Pseudomonas aeruginosa UI 60690 and methicillin resistant Staphylococcus aureus, (MRSA) was also carried out using the disc-diffusion method. All tested extracts exhibited very strong antioxidant properties when compared to Vitamin E (alpha-tocopherol) with percent inhibition of 89-98% in the FTC and 60-95% in the TBA assays. In the DPPH method, H. herbacea exhibited the strongest radical scavenging activity with an IC50 value of 32 microg/ml. The results from the Griess assay showed that the tested extracts are weak inhibitors of NO synthase. However, all tested extracts exhibited moderate cytotoxic properties against CEM-SS cell line giving CD50 values in the range of 21-41 microg/ml. In the antibacterial bioassay, the stems and the roots of H. capitellata showed moderate activity against the 4 tested bacteria while the leaves showed moderate activity towards B. subtilis B28, MRSA and P. aeruginosa only. The roots of H. dichotoma showed strong antibacterial activity against all 4 bacteria. All other extracts did not exhibit any antibacterial activity.     

Xanthatin and xanthinosin from the burs of Xanthium strumarium L. as potential anticancer agents

Xanthatin and xanthinosin, 2 sesquiterpene lactones isolated from the burs of Xanthiun strumarium L. (cocklebur), showed moderate to high in vitro cytotoxic activity in the human cancer cell lines WiDr ATCC (colon), MDA-MB-231 ATCC (breast), and NCI-417 (lung). Xanthatin and xanthinosin were purified as the result of a multi-screening bioassay-guided study of wild plant species of the family Asteraceae, collected from various sites in Saskatchewan, Canada. Seventy-five extracts at a single concentration of 100 microg/mL were evaluated for in vitro cytotoxicity to the human cancer cell lines used. The chloroform extract of Carduus nutans L. (nodding thistle) aerial parts (IC50, 9.3 microg/mL) and the hexane extract of Echinacea angustifolia DC. (narrow-leaved purple coneflower) root (IC50, 4.0 microg/mL) were moderately to highly cytotoxic to the lung cancer cell line. The chloroform extracts of X. strumarium L. burs and Tanacetum vulgare L. (tansy) aerial parts exhibited the highest cytotoxicity for all cell lines tested; their IC50 values, obtained from multidose testing, ranged from 0.1 to 6.2 microg/mL (X. strumarium) and from 2.4 to 9.1 microg/mL (T. vulgare). Further purification of the chloroform fraction of X. strumarium yielded xanthatin and xanthinosin in high yields. This is the first time that these compounds have been reported in the burs of X. strumarium. Their IC50 values are also reported herein.     

Phytochemical Screening,Antioxidant Assay and Cytotoxic Profile for Different Extracts of Chrysopogon zizanioides Roots

The Chrysopogon zizanioides plant possesses multiple traditional uses, especially in therapeutics, but only a few articles have reported its biological activity. Hence, the present study was planned to explore the phytochemical constituents, cytotoxic potential, radical scavenging activity, and GC/MS (Gas chromatography & Mass spectrometry) analysis of the vetiver root extracts. The roots extracted with different solvents exhibited more significant phytochemical constituents in polar solvents in comparison to non-polar ones, favoring the extraction of a greater number of components in highly polar solvents. All the extracts were tested for their cytotoxicity using SRB (Sulforhodamine B) assay. They confirmed ethanolic extract as a potent extract with GI₅₀ 56±0.5 μg/ml in oral cancer (SCC-29B) along with no cytotoxicity in healthy cells (Vero cells), making it a safer therapeutic option in comparison to standard Adriamycin. This extract was also analyzed for its antioxidant potential by DPPH (1,1-Diphenyl-2-picrylhydrazyl) assay with IC₅₀ value 10.73 μg/ml, which was quite comparable to Ascorbic acid having IC₅₀ value 4.61 μg/ml. The quantitative analysis of ethanolic extract exhibited 107 compounds amongst which Khusenic acid, Ascorbic acid, Junipen, gamma-Himachalene, alpha-Guaiene were the majorly occurring compounds that can be explored further for their cytotoxic activity.     

Spectroscopic identification of new ellagitannins and a trigalloyl-glucosylkaempferol from an extract of Euphorbia cotinifolia L. with antitumour and antioxidant activity

From an extract of leaves and small branches of Euphorbia cotinifolia L., 17 polyphenols were isolated including two new ellagitannins and a trigalloyl-glucosylkaempferol. Based on extensive spectral data (UV, ESI-MS, 1H NMR, DEPT and 1D/2D NMR) and chemical studies, their structures were characterized as 1-O-galloyl-3,6-hexahydroxydiphenoyl-D-B1,4-glucopyranose (5), 1-O-galloyl-3,6-valoneoyl-D-B1,4-glucopyranose (6), and kaempferol 3-O-(2",3",6"-tri-O-galloyl)-beta-D-glucopyranoside (13). Biological evaluation indicated that the 80% aqueous methanol extract (AME), chloroform extract (CE), and some pure compounds have potent scavenging activity in the DPPH assay with SC50 values lower than that of ascorbic acid, especially 5, 7-9, and a mixture of hyperin 6"-gallate (11) and isoquercitrin 6"-gallate (12). Moreover, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) cell viability assay, 6 and 8 exhibited the highest inhibition of human hepatocellular carcinoma cells (Hep-G2), while AME, CE, 5, 7, 9, and the mixture of 11 and 12 were found to be moderate growth inhibitors according to their IC50 values. In addition, AME, 5, and 8 exhibited significant antiproliferative activity against colon carcinoma cells (HCT-116); however, CE and the other examined compounds displayed moderate to low antitumour activity against HCT-116 cells.     

Biological screening of traditional preparations from some medicinal plants used as antidiarrhoeal in Kinshasa, Congo.

Forty six aqueous extracts from 38 medicinal plant species belonging to different families were selected on the basis of their traditional medicinal use as antidiarrhoeic agents. They were submitted in a broad biological screening including antibacterial, antiamoebic and antispasmodic activities. The results of the testing have indicated that 37 extracts (80.43%), 33 (71.74%) and 32 (69.54%) exhibited some level of antibacterial, antiamoebic and antispasmodic activity respectively. Only 8 plant extracts (17.39%) would act as antidiarrhoeic agents by a triple pronounced antibacterial, antiamoebic and antispasmodic action. They include aqueous extracts from Euphorbia hirta whole plant, leaves of Psidium guajava and Tithonia diversifolia, root bark of Alchornea cordifolia, Heinsia pulchella, Paropsia brazzeana, Rauwolfia obscura and Voacanga africana.     

Anti-herpes simplex virus activity of sulfated galactans from the red seaweeds Gymnogongrus griffithsiae and Cryptonemia crenulata

This study presents the chemical composition and antiviral activity against herpes simplex virus type 1 (HSV-1) and 2 (HSV-2) of sulfated galactan crude extracts and main fractions obtained from two red seaweeds collected in Brazil, Gymnogongrus griffithsiae and Cryptonemia crenulata. Most of the eighteen tested products, including homogeneous kappa/iota/nu carrageenan and DL-galactan hybrid, exhibited antiherpetic activity with inhibitory concentration 50% (IC50) values in the range 0.5-5.6 microg/ml, as determined in a virus plaque reduction assay in Vero cells. The galactans lacked cytotoxic effects and showed a broad spectrum of antiviral activity against HSV-1 and HSV-2. No direct virus inactivation was observed after virion treatment with the galactans. The mode of action of these compounds could be mainly ascribed to an inhibitory effect on virus adsorption. Most importantly, a significant protection against a murine vaginal infection with HSV-2 was afforded by topical treatment with the sulfated galactans.     

Cytotoxic effects of a decoction of Nigella sativa, Hemidesmus indicus and Smilax glabra on human hepatoma HepG2 cells

A decoction of Nigella sativa seeds, Hemidesmus indicus root and Smilax glabra rhizome is used by traditional medical practitioners in Sri Lanka to treat cancer and has been shown to prevent chemically induced carcinogenesis in rats. The cytotoxicity of the decoction and the individual plant extracts were tested on the human hepatoma HepG2 cell line. The effects of 24 h incubation with different concentrations (0--50 mg/ml) of the extracts on HepG2 cells were determined. Results from MTT and SRB assays, and [(14)C]-leucine and [(3)H]-thymidine uptake demonstrated that the decoction had a strong dose-dependent cytotoxic activity. The greatest inhibitory effects were observed on DNA synthesis with both the decoction (91+/-S.E. 3.7% inhibition) and N. sativa plant extract (88+/-3.8%) even at low concentrations (5 mg/ml). The three individual plant extracts were cytotoxic in the order of potency N. sativa>H. indicus>S. glabra. Flow cytometric analysis using Annexin V and propidium iodide staining showed that after 24 h exposure to the decoction, cells were in the late stage of apoptosis and/or necrosis. Further experiments are worthwhile to determine the anticancer potential of this plant decoction and its components.     

Antiviral activity of Rwandan medicinal plants against human immunodeficiency virus type-1 (HIV-1)

Selected plants used in Rwandan traditional medicine for the treatment of infections and/or rheumatoid diseases were investigated for antiviral activity in vitro against human immunodeficiency virus type-1 (HIV-1). Of the 38 tested 80% ethanolic extracts, belonging to plants of 21 different families only the extracts from the leaves of Aspilia pluriseta (Asteraceae) and Rumex bequaertii (Polygonaceae) had interesting selectivity indices (SI = ratio of the 50% cytotoxic concentration to the 50% effective antiviral concentration) higher than 1. Further fractionation of the initially antivirally inactive ethanolic extract of Tithonia diversifolia, however, led to an aqueous fraction with a high anti-HIV-1 activity (SI > 461), indicating that the cytotoxicity of some plant components may mask the antiviral properties of the active plant substances in total plant extracts.     

Synthesis of 1-(2-deoxy-beta-D-ribofuranosyl)-2,4-difluoro-5-substituted-benzenes: "thymine replacement" analogs of thymidine for evaluation as anticancer and antiviral agents

A group of unnatural 1-(2-deoxy-beta-D-ribofuranosyl)-2,4-difluorobenzenes having a variety of C-5 two-carbon substituents [-C...C-X, X = I, Br; -C...CH; (E)-CH=CH-X, X = I, Br; -CH=CH2; -CH2CH3; -CH(N3) CH2Br], designed as nucleoside mimics, were synthesized for evaluation as anticancer and antiviral agents. The 5-substituted (E)-CH=CH-I and -CH2CH3 compounds exhibited negligible cytotoxicity in a MTT assay (CC50 = 10(-3) to 10(-4)M range), relative to thymidine (CC50 = 10(-3) to 10(-5)M range), against a variety of cancer cell lines. In contrast, the C-5 substituted -C...C-I and -CH(N3)CH2Br compounds were more cytotoxic (CC50 = 10(-5) to 10(-6)M range). The -C...C-I and -CH2CH3 compounds exhibited similar cytotoxicity against non-transfected (KBALB, 143B) and HSV-1 TK+ gene transfected (KBALB-STK, 143B-LTK) cancer cell lines expressing the herpes simplex virus type 1 (HSV-1) thymidine kinase gene (TK+). This observation indicates that expression of the viral TK enzyme did not provide a gene therapeutic effect. The parent group of 5-substituted compounds, that were evaluated using a wide variety of antiviral assay systems [HSV-1, HSV-2, varicella-zoster virus (VZV), vaccinia virus, vesicular stomatitis, cytomegalovirus (CMV), and human immunodeficiency (HIV-1, HIV-2) viruses], showed that this class of unnatural C-aryl nucleoside mimics are inactive and/or weakly active antiviral agents.     

Effects of two plant extracts on larval leafminer Liriomyza trifolii (Diptera: Agromyzidae) in tomatoes

Aqueous extracts from two plants, Urginea maritima L. (Liliaceae) and Euphorbia myrsinites L. (Euphorbiaceae), were tested for their insecticidal activity against the leafminer Liriomyza trifolii (Burgess) on infested tomato, Lycopersicon esculentum Mill., plants in the laboratory and field. Two grams of plant material was extracted with 100 ml of water and then diluted 1:100, 1:50, and 1:25 with distilled water. Diluted plant extract was either applied to the infested tomato leaves or by soil drench and was compared with foliar application of cyromazine. All dilutions of both plant extracts caused significant control of the leafminer larvae and maintained populations below those of the nontreated control plants in all trials. Only at the most concentrated dilutions (1:25) were the plant extracts statistically similar to the cyromazine treatment. Furthermore, greenhouse yields from all of the foliar treatments were statistically similar to the cyromazine treatment and significantly better than the nontreated control. Four species of leafminer parasitoids were found in the greenhouse; however, the percentage of parasitism was significantly less in all treated replicates than in the nontreated control replicates. Aqueous extracts from these two plant extracts exhibited both translaminar and systemic activity and are potential candidates as new organic insecticides.     

Anti-plasmodial activity of Dicoma tomentosa (Asteraceae) and identification of urospermal A-15- O-acetate as the main active compound

ABSTRACT: BACKGROUND: Natural products could play an important role in the challenge to discover new anti-malarial drugs. In a previous study, Dicoma tomentosa (Asteraceae) was selected for its promising anti-plasmodial activity after a preliminary screening of several plants traditionally used in Burkina Faso to treat malaria. The aim of the present study was to further investigate the antiplasmodial properties of this plant and to isolate the active anti-plasmodial compounds. METHODS: Eight crude extracts obtained from D. tomentosa whole plant were tested in vitro against two Plasmodium falciparum strains (3D7 and W2) using the p-LDH assay (colorimetric method). The Peters' four-days suppressive test model (Plasmodium berghei-infected mice) was used to evaluate the in vivo anti-plasmodial activity. An in vitro bioguided fractionation was undertaken on a dichloromethane extract, using preparative HPLC and TLC techniques. The identity of the pure compound was assessed using UV, MS and NMR spectroscopic analysis. In vitro cytotoxicity against WI38 human fibroblasts (WST-1 assay) and haemolytic activity were also evaluated for extracts and pure compounds in order to check selectivity. RESULTS: The best in vitro anti-plasmodial results were obtained with the dichloromethane, diethylether, ethylacetate and methanol extracts, which exhibited a high activity (IC50 [less than or equal to] 5 mug/ml). Hot water and hydroethanolic extracts also showed a good activity (IC50 [less than or equal to] 15 mug/ml), which confirmed the traditional use and the promising anti-malarial potential of the plant. The activity was also confirmed in vivo for all tested extracts. However, most of the active extracts also exhibited cytotoxic activity, but no extract was found to display any haemolytic activity. The bioguided fractionation process allowed to isolate and identify a sesquiterpene lactone (urospermal A-15-O-acetate) as the major anti-plasmodial compound of the plant (IC50 < 1 mug/ml against both 3D7 and W2 strains). This was also found to be the main cytotoxic compound (SI =3.3). While this melampolide has already been described in the plant, this paper is the first report on the biological properties of this compound. CONCLUSIONS: The present study highlighted the very promising anti-plasmodial activity of D. tomentosa and enabled to identify its main active compound, urospermal A-15-O-acetate. The high antiplasmodial activity of this compound merits further study about its anti-plasmodial mechanism of action. The active extracts of D. tomentosa, as well as urospermal A 15-Oacetate, displayed only a moderate selectivity, and further studies are needed to assess the safety of the use of the plant by the local population.     

Jatrophane diterpenes from Euphorbia spp. as modulators of multidrug resistance in cancer therapy

A phytochemical investigation of the aerial parts of Euphorbia spp., considered one of the most common elements of Mediterranean landascape, led to the isolation of a large number of bioactive plant metabolites, belonging to the diterpenes family. Above all, over seventy jatrophane, modified jatrophane, segetane, pepluane, and paraliane diterpenoids, fifty of them reported for the first time, were extracted, purified and characterized from Euphorbia dendroides, Euphorbia characias, Euphorbia peplus, Euphorbia paralias and Euphorbia helioscopia. These compounds showed interesting pharmacological activities. In particular, jatrophanes, modified jatrophanes and lathyranes exhibited a potent inhibitory activity against P-glycoprotein (Pgp), a membrane protein that confers cellular ability to resist lethal doses of certain cytotoxic drugs by pumping them to the outside, thus resulting in a reduced cytotoxicity. Among the others, our chemical survey led to isolation of the most powerful inhibitors of daunomycin-efflux activity isolated to date for this class of inhibitors, named euphodendroidin D and pepluanin A. Their efficiency was found to be at least two-fold higher than the conventional modulator cyclosporin A, taken as a reference. In addition, the isolation of a high number of natural structurally-related analogues allowed us to perform Structure Activity Relationship (SAR) studies, without any chemical modification, which gave information on the key pharmacophoric elements of these new class of promising drugs. A further set of diterpene analogues, very recently isolated from sun spurge, E. helioscopia, individually investigated for their Pgp- and BCRP-inhibiting properties, appeared to be specific inhibitors of Pgp since they showed no significant activity against BCRP, thus resembling to the third-generation class of specific MDR inhibitors.     

Synthesis of unnatural 7-substituted-1-(2-deoxy-beta-D-ribofuranosyl)isocarbostyrils: "thymine replacement" analogs of deoxythymidine for evaluation as antiviral and anticancer agents

A group of unnatural 1-(2-deoxy-beta-D-ribofuranosyl)isocarbostyrils having a variety of C-7 substituents [H, 4,7-(NO2)2, I, CF3, CN, (E)-CH=CH-I, -C triple bond CH, -C triple bond C-I, -C triple bond C-Br, -C=C-Me], designed as nucleoside mimics, were synthesized for evaluation as anticancer and antiviral agents. This class of compounds exhibited weak cytotoxicity in a MTT assay (CC50 = 10(-3) to 10(-5) M range) with the 4,7-dinitro derivative being the most cytotoxic, relative to thymidine (CC50 = 10(-3) to 10(-5) M range), against a variety of cancer cell lines. The 4,7-dinitro, 7-I and 7-C triple bond CH compounds exhibited similar cytotoxicity against non-transfected (KBALB, 143B), and HSV-1 TK+ gene transfected (KBALB-STK, 143B-LTK) cancer cell lines possessing the herpes simplex virus type 1 (HSV-1) thymidine kinase gene (TK+). This observation indicates that these compounds are not substrates for HSV type-1 TK, and are therefore unlikely to be useful in gene therapy based on the HSV gene therapy paradigm.     

New Bioactive Macrocyclic Diterpenoids from Euphorbia helioscopia

Three new macrocyclic diterpenoids, euphoscopoids A – C ( 1 – 3 ), including two new jatrophanes and a new lathyrane, were isolated from the whole plant of Euphorbia helioscopia. Their structures were elucidated by spectroscopic methods. Antifeedant and cytotoxic activities of these isolates were evaluated. All compounds showed significant antifeedant activity against a generalist plant‐feeding insect, Helicoverpa armigera, with EC₅₀ values ranging from 2.05 to 4.34 μg/cm². In addition, compound 2 showed moderate cytotoxicity against tumor cell lines NCI‐H1975, HepG2, and MCF‐2, while compounds 1 and 3 were not active at 80 μm . The results suggested not only the defensive function of macrocyclic diterpenoids in E. helioscopia against insect herbivores, but also their potential applications as new natural insect antifeedants.     

Trypanocidal and cytotoxic effects of 30 Ethiopian medicinal plants

Trypanocidal and cytotoxic effects of traditionally used medicinal plants of Ethiopia were evaluated. A total of 60 crude plant extracts were prepared from 30 plant species using CH2Cl2 and MeOH. Effect upon cell proliferation by the extracts, for both bloodstream forms of Trypanosoma brucei brucei and human leukaemia HL-60 cells, was assessed using resazurin as vital stain. Of all CH2Cl2 and MeOH extracts evaluated against the trypanosomes, the CH2Cl2 extracts from five plants showed trypanocidal activity with an IC50 value below 20 microg/mL: Dovyalis abyssinica (Flacourtiaceae), IC50 = 1.4 microg/mL; Albizia schimperiana (Fabaceae), IC50 = 7.2 microg/mL; Ocimum urticifolium (Lamiaceae), IC50 = 14.0 microg/mL; Acokanthera schimperi (Apocynaceae), IC50 = 16.6 microg/mL; and Chenopodium ambrosioides (Chenopodiaceae), IC50 = 17.1 microg/mL. A pronounced and selective killing of trypanosomes with minimal toxic effect on human cells was exhibited by Dovyalis abyssinica (CH2Cl2 extract, SI = 125.0; MeOH extract, SI = 57.7) followed by Albizia schimperiana (CH2Cl2 extract, SI = 31.3) and Ocimum urticifolium (MeOH extract, SI = 16.0). In conclusion, the screening of 30 Ethiopian medicinal plants identified three species with good antitrypanosomal activities and low toxicity towards human cells. Dovyalis abyssinica might be a promising candidate for phytotherapy of trypanosomiasis.     

Antioxidant activity and cytotoxicity of methanol extracts from aerial parts of Korean salad plants

The aim of this investigation was to determine the content of total phenolics, antioxidant activity and cytotoxicity of methanol extracts from the aerial parts of 11 Korean medicinal salad plants. The highest total phenolic content of the methanol extracts was found in Aster scaber (17.1 mg 100 g(-1)), followed by Ixeris dentate (16.4 mg 100 g(-1)), Aster yomena (12.0 mg 100 g(-1)) and Sedum sarmentosum (9.1 mg 100 g(-1)) of FW. Methanol extracts of Ixeris dentate and Aster scaber at 50 microg mL(-1) exhibited the highest DPPH radical scavenging activity by 86.4 and 83.3%, respectively. It was registered a dose-dependent increase of DPPH free radical scavenging activity. Total phenolic content of the studied plant extracts was correlated with the DPPH radical scavenging activity. It was found by means of MTT assay, that cytotoxicity of the methanol extracts was the highest against HCT-116. Methanol extracts from Petasites japonicus (IC(50)<25.0 microg mL(-1)) showed the highest activity against HCT-116, following by Angelica gigas (34.75 microg mL(-1)), Erythronium japonicum (44.06 microg mL(-1)), and Aster scaber (54.87 microg mL(-1)). In conclusion, the studied salad plants have high total phenolics content and high antioxidant activity. These plants dose-dependently increased DPPH free radical scavenging activity. The total phenolics level was highly correlated with the free radical scavenging activity. Most of the studied salad plants have potent cytotoxicity activity. The results of this investigation suggest that the extracts of studied salad plants could be an addition to basic medicine for some diseases.     

Acaricidal and cytotoxic activities of extracts from selected genera of Australian Lamiaceae

Crude foliar extracts of 67 species from six subfamilies of Australian Lamiaceae were screened by whole organism contact toxicity on the polyphagous mite Tetranychus urticae Koch (Acari: Tetranychidae) by using a Potter precision spray tower. Cytotoxicity assessments against insect cell lines from Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) and Drosophila melanogaster (Meigen) (Diptera: Drosophilidae) also were made. The Spodoptera cell line was more susceptible to extracts than the Drosophila cellline. No direct correlation was observed between the two screening methods, but several interesting relationships were identified. Extracts from subfamilies Ajugoideae, Scutellarioideae, Chloanthoideae, Viticoideae and Nepetoideae showed acaricidal activity, whereas only those from Ajugoideae and Nepetoideae displayed potent cytotoxic effects. A range of activities was observed for the 25 species of Plectranthus, 14 of which showed moderate-to-high contact toxicity against T. urticae. Overall, the lowest toxicity was observed for extracts from the plant subfamily Prostantheroideae, which showed little contact toxicity or cytotoxicity for the 18 extracts studied.     

Mycotoxins produced from fungi isolated from foodstuffs and soil: comparison of toxicity in fibroblasts and rat feeding tests

Thirty-nine isolates of fungi obtained from foodstuffs and soil samples from various parts of the world have been identified. The isolates were grown on a solid rice medium, and extracts were prepared with 50% aqueous methanol. The extracts were examined for toxicity in the following systems: (i) cytotoxicity to cultured normal human diploid skin fibroblasts (proliferating and nonproliferating) and mouse fibroblasts; (ii) skin toxicity after topical application on rats; and (iii) rat feeding tests in which rats were examined for death, overt pathological effects including congestion and hemorrhage of tissues, weight loss, food refusal, and uterine growth. Sixteen culture extracts were highly toxic as indicated by death, congestion and hemorrhage of tissues, and net weight loss. One half of the isolates were highly cytotoxic (50% lethal concentration, 0.01 to 5 micrograms/ml) as indicated by the ability to cause death and disintegration of 3T3 Swiss mouse fibroblasts and human diploid skin fibroblasts during 3 to 4 days in culture. The remainder were moderately cytotoxic (50% lethal concentration, 5 to 250 micrograms/ml). Four culture extracts were highly toxic by some clinical criteria but did not cause congestion and hemorrhage of tissues and were weakly cytotoxic (50% lethal concentration, 250 to 5,000 micrograms/ml). Six culture extracts exhibited moderate toxicity (weight loss only) and low cytotoxicity (50% lethal concentration, 3,000 to 50,000 micrograms/ml). Four culture extracts caused uterine enlargement as the major clinical sign, suggesting the presence of zearalenone. Eleven culture extracts were weakly cytotoxic and caused no major clinical signs, except skin toxicity in two extracts.(ABSTRACT TRUNCATED AT 250 WORDS)