Several species of the genus Euphorbia (Euphorbiaceae) have been tested for their efficiency as antiviral and antitumour agents, partly based on information concerning plants that have traditionally been used as medication to treat various human diseases (Bernal & Correa 1990, Unander et al. 1995. In fact, pronounced antiviral activity has been reported in several species of the genus Euphorbia, against polio, coxsackie, and rhinoviruses (Vlietinck et al. 1986, 1995, Ninomiya et al. 1990, Unander et al. 1995. Additionally, antitumour activity against sarcoma 180 ascites, leukemia in mice, and cytotoxic activity against certain cancer cell lines has also been observed (Itokawa et al. 1989, Wu et al. 1991, Fatope et al. 1996.There seems to be increasing possibility of finding biological activity among plants with recorded medicinal uses rather than from plants randomly selected (Unander et al. 1995, Cordell 1995. Furthermore, selection of plants gives better criteria for screening programs especially in its initial phases, compared to the screening of compounds isolated and/or purified from natural products (Kusumoto et al. 1995, Cordell 1995, Baker et al. 1995.Finally, the strategy for research and in vitro evaluation of biological activity of natural products, has changed in the past few years. One of the recent developments is the highly automated bioassay screening method based on colorimetric assays, that quantify the proliferation of cell cultures (Mosmann 1983, Denizot & Lang 1986). These techniques, considered rapid and inexpensive for the evaluation of antitumour (Carmichael et al. 1987, Rubinstein et al. 1990) and antiviral activity (Weislow et al. 1989) of a large number of natural products, have also permitted the isolation and purification of biologically active principles (Cordell 1995, Baker et al. 1995.The objective of our work was to evaluate, using colorimetric assays, the in vitro antiherpetic and cytotoxic activity of some Euphorbia species that are known in Colombia, to have traditional medical uses against skin infections such as ulcers, warts, cancers, tumors, and possibly diseases of viral origin (Garcia-Barriga 1974, Perez 1975, Vasquez 1982, Bernal & Correa 1990, Piñeros et al. 1992. MATERIALS AND METHODSPlant collection -The species were collected in different municipalities of the Department of Antioquia and deposited in the herbarium of the University of Antioquia, Medellín, Colombia. E. cotinifolia, was collected in Girardota, at a mean altitude of 350 m; a voucher specimen was deposited under the number HUA 115472. E. cestrifolia was collected in Guarne, at a mean altitude of 2,000 m; a voucher specimen was deposited under the number HUA 95065. E. tirucalli, E. arenaria, and E. pulcherrima were collected in Medellín, at a mean altitude of 450 m; voucher specimens were deposited under the numbers RC11383, HUA 55275, RC11384, respectively. The species E. heterophyla, E. cyatophora, E. graminea, E. cf. cotinifolia and Euphorbia sp. were collected in San Jerónimo, at a mean altitude of...

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Two essential oils of Lippia alba (Mill.) N.E. Brown (Verbenacea)

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.

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A series of synthetic spongiane-type diterpenes have been tested in vitro for their potential antitumor and antiherpetic activity. Although the antiviral activity of these compounds against herpes simplex virus type 2 (HSV-2) was very weak, some compounds exhibited relevant cytotoxicity in the human tumor cell lines HeLa and HEp-2. The biological activity of formyl spongianes is reported for the first time. With the present study, some structure−activity trends are suggested for the cytotoxic activity of these sponge-derived natural products.

The abietane-type diterpenoid (+)-ferruginol (1), a bioactive compound isolated from several plants, has attracted much attention as consequence of its pharmacological properties, which includes antibacterial, antifungal, antimicrobial, cardioprotective, anti-oxidative, anti-plasmodial, leishmanicidal, anti-ulcerogenic, anti-inflammatory and antitumor actions. In this study, we report on the antiviral evaluation of ferruginol (1) and several analogues synthesized from commercial (+)-dehydroabietylamine. Thus, the activity against Human Herpesvirus type 1, Human Herpesvirus type 2 and Dengue Virus type 2, was studied. Two ferruginol analogues showed high antiviral selectivity index and reduced viral plaque-size in post-infection stages against both Herpes and Dengue viruses. A promising lead, compound 8, was ten-fold more potent (EC50 = 1.4 μM) than the control ribavirin against Dengue Virus type 2. Our findings suggest that the 12-hydroxyabieta-8,11,13-triene skeleton, which is characteristic of the diterpenoid ferruginol (1), is an interesting molecular scaffold for development of novel antivirals. In addition, the cytotoxic and antifungal activities of the synthesized ferruginol analogues have also been investigated. (©)20155 Elsevier Science. All rights reserved.

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