Diversity of Pharmacological Properties in Chinese and European Medicinal Plants: Cytotoxicity, Antiviral and Antitrypanosomal Screening of 82 Herbal Drugs

: In an extensive screening, the antiviral, antitrypanosomal and anticancer properties of extracts from 82 plants used in traditional Chinese medicine and European phytomedicine were determined. Several promising plants that were highly effective against hepatitis B virus (HBV), bovine viral diarrhoea virus (BVDV)—a flavivirus used here as a surrogate in vitro model of hepatitis C virus, trypanosomes ( Trypanosoma brucei brucei ) and several cancer cell lines were identified. Six aqueous extracts from Celosia cristata, Ophioglossum vulgatum, Houttuynia cordata, Selaginella tamariscina, Alpinia galanga and Alpinia oxyphylla showed significant antiviral effects against BVDV without toxic effects on host embryonic bovine trachea (EBTr) cells, while Evodia lepta , Hedyotis diffusa and Glycyrrhiza spp. demonstrated promising activities against the HBV without toxic effects on host human hepatoblastoma cells transfected with HBV-DNA (HepG2 2.2.15) cells. Seven organic extracts from Alpinia oxyphylla, Coptis chinensis, Kadsura longipedunculata, Arctium lappa, Panax ginseng, Panax notoginseng and Saposhnikovia divaricata inhibited T. b. brucei. Moreover, among fifteen water extracts that combined high antiproliferative activity (IC 50 0.5–20 µg/mL) and low acute in vitro toxicity (0–10% reduction in cell viability at IC 50 ), Coptis chinensis presented the best beneficial characteristics. In conclusion, traditional herbal medicine from Europe and China still has a potential for new therapeutic targets and therapeutic applications.


Introduction
Traditional Chinese medicine (TCM) has a long history starting with the Shang Dynasty around 1500 BC and officially uses approximately 4773 herbs, while the number of locally used plants is probably much higher [1].Clinical efficacy was shown in various examples, one of the best known is that of artemisinin from Artemisia annua, commonly used against malaria, but also effective against T. b. brucei, viral infections and cancer [2][3][4][5][6][7][8].
European medicine also has a long tradition of at least 2500 years with the two important early scholars Hippocrates and Dioscorides who described more than 400 medicinal plants 2000 years ago, many of which are still in use today [9].Many pure therapeutic agents used in modern medicine were originally based on herbal medicine; in fact, the process of developing new drugs from European herbal medicine is still alive and important discoveries are regularly made [10,11].Even though the theoretical concept of traditional medicine differs between Europe and China, often the same plants were and are still used in both cultures to treat the same or similar health disorders.Modern European phytotherapy also includes important herbal medicines from Africa and America.
Even though the diversity of plants and possible natural products is vast, the number of targets is usually limited (Table 1).Most natural products target proteins, biomembranes or DNA unselectively.Selective interaction is often the case when especially alkaloids mimic signal molecules and interact with receptors or enzymes.It is often possible to conclude from the type of the natural products to their most likely mode of action.Saponins and monoterpenes are active on the biomembrane, while polyphenols usually interact with proteins.Alkaloids also interact with proteins or the DNA.
The formations of covalent and of non-covalent bonds are the two modes of action that form the basis of all interactions between proteins and natural products.
The two main targets for the formation of covalent bonds are free amino and free SH groups.Aldehydes, isothiocyanates and epoxids can form covalent bonds with free amino groups while sesquiterpene lactones, disulfides (e.g., allicin), polyacetylenes and epoxides can form covalent bonds with free SH groups.
Table 1.Targets in animal cells, bacteria cells and viruses [12].The second mechanism of maybe even greater importance due to its universality is the formation of non-covalent bonds between phenolic OH-groups and amino groups.The proton of the phenolic OH-group can partly dissociate under physiological conditions so that unspecific interactions by forming strong, ionic bonds occur with proteins.Tannins are especially effective due to their large number of hydroxyl groups.
All of these interactions will change the three dimensional structure of the protein and thus inactivate it.The omnipresence of these unspecific natural products in plants explains the efficacy of many plant extracts.They are responsible for the great number of "hits" usually occurring in extended screenings of medicinal plant extracts (Table 2).
Table 2. Main Compounds of Plants used in this study [9,13].

Family Species Main Compounds Acanthaceae
Andrographis paniculata Diterpenelactones

Equisetum hiemale
Flavonoids, silicic acids  Hepatitis B and hepatitis C are responsible for 75% of all cases of liver diseases worldwide, often causing cirrhosis and hepatocellular carcinoma [14,15].Hepatitis B and hepatitis C account for the most problematic viral infections, since the standard treatment with pegylated IFN-γ and the purine nucleoside analogues lamivudine and ribavirin have severe side effects while being at the same time ineffective for 50% of the patients [14,16].Thus, new drugs are urgently needed [17].Together with the bovine viral diarrhoea virus (BVDV), and the Japanese Encephalitis virus, hepatitis C virus (HCV) belongs to the Flaviviridae family.As BVDV, whose cytopathic strains induce a lytic infection in some cell lines, such as embryonic bovine trachea (EBTr) cells, is easier to manipulate and lacks human infectivity, this is commonly used as in vitro model for infections of this viral family [18].
Our knowledge of the natural products of many plants used in European and Chinese phytomedicine is broad (Table 2), however, many new discoveries are still possible.Previously, several studies demonstrated the promising potential of traditional phytomedicine for the discovery of new antiviral drugs.Artemisinin and related compounds proved effective in screening assays against viral hepatitis [6,7,19].In water extracts of Terminalia chebula, Sanguisorba officinalis, Rubus coreanus and Rheum palmatum, Kim et al. [20] discovered prominent anti-hepatitis B virus (HBV) activities.The ethanolic extract of Hypericum perforatum, a well-established drug for treatment of depression [9] was also shown to be active against the HBV [21].Laxative anthraquinones isolated from Rheum palmatum demonstrated significant effects against HBV [22] and saikosaponins from Bupleurum species were previously shown to lower significantly the HBV level in the HepG2 2.2.15 assay [23].HepG2 2.2.15 is a stable cell line infected with the HBV.The assay measures the production of secreted HBV from the cell by using real time quantitative PCR.
Parasites such as protozoa and helminths cause a major health threat in many tropical countries [24], while suitable drugs are still rare [25].Blood parasites of the genus Trypanosoma (Trypanosoma brucei rhodesiense and T. b. gambiense) are responsible for African trypanosomiasis (sleeping sickness) with serious consequences for human health and economy.Due to the high infectivity of African human trypanosomes, T. b. brucei is commonly used as model organism with similar morphology and biochemical processes, while being only infective for cattle [24,26,27].This subspecies causes the cattle epidemic nagana, it is responsible for severe financial loss of 1340 billion USD per year [28].
Currently, only four drugs are approved internationally for the treatment of humans against sleeping sickness: suramin, pentamidine, melarsoprol and eflornithine.Diminazene, another effective antitrypanosomal drug, is only approved for the use on animals because of severe side effects [24].Even the drugs approved for human use are responsible for serious side effects, and furthermore, the parasites develop increasing resistance to them [29][30][31][32].This situation makes the discovery of new, effective drugs an urgent task of the 21st century [33][34][35].
When considered together, enterohepatic tumors, i.e., those affecting the liver, the biliary duct, gallbladder and the intestine, constitute the first cause of death due to cancer.Although in many cases surgery and radiotherapy are efficacious, these therapeutic strategies cannot always be applied.Moreover, even when the removal of tumors is possible, pre-and post-operative pharmacological adjuvant regimens are often needed.However, one important limitation to the use of cytostatic drugs to treat enterohepatic tumors is that they generally exhibit marked resistance to currently available pharmacological approaches and the development of resistance during treatment [36].
Many natural products and derivatives thereof belong to the standard repertoire of cancer chemotherapy.Examples are Vinca alkaloids, such as vincristine, vinblastine and vinorelbine, obtained from Madagascar periwinkle (Catharanthus rosea).Also taxanes such as paclitaxel and docetaxel, which are produced from the bark of Pacific yew (Taxus), podophyllotoxins, such as etoposide and teniposide, derivatives of the genus Podophyllum, and camptothecin, derived from the Asian "Tree of Happiness" (Camptotheca acuminata) and its derivatives, irinotecan and topotecan, are natural products from TCM plants [4].
In this study, extracts from 82 traditional medicinal plants were screened against HBV and flaviviruses, T. b. brucei and several cancer cell lines.Our aim was to detect new sources of active compounds for the possible treatment of these important causes of diseases.

Authentication of Plant Material
The TCM plants were genetically identified by DNA barcoding to confirm the identity and to exclude adulterations.DNA was isolated from plant drugs; their chloroplast rbcL gene was amplified and sequenced.The obtained sequences were authenticated with sequences obtained from sample species of the Botanical Garden of Heidelberg and databases.Voucher specimens of the plant material were deposited at the Department of Biology, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Germany.Additionally, the plants were authenticated by visual and microscopic techniques.

Extract Preparation
Five hundred grams of dry plant material was powdered and extracted with dichloromethane, methanol and water under moderate heat using a reflux condenser for 4 hours.The extracts obtained were concentrated using the rotation evaporator, stored at −40 °C under exclusion of light and dried under vacuum prior to the experiments.Dried extracts were dissolved in DMSO for the experiments.

Test Organisms
T. b. brucei TC 221 were originally obtained from Prof. Peter Overath (Max-Plank Institut für Biologie, Tübingen) by Dr. D. Steverding before being cultured at the IPMB, Heidelberg since 1999.HeLa cancer cells and Cos7 fibroblast cells (African green monkey kidney cells immortalized with the monkey virus SV40) were cultured at the IPMB, Heidelberg for several years; Hep G2, SK-Hep1 and LS 174T, HepG2 2.2.15 and EBTr cells were cultured at the Laboratory of Experimental Hepatology and Drug Targeting (HEVEFARM), University of Salamanca, CIBERehd, Spain.
The MTT cell viability assay was used to determine cytotoxicity in Cos7 and HeLa cells [39,40].Cells during the logarithmic growth period were seeded in 96 well plates (Greiner Labortechnik) at concentrations of 2 × 10 4 cells/well and grown for 24 h.Dried and powdered extracts were dissolved in DMSO before being serially diluted to 10 concentrations in 96 well plates.Cells were incubated with the extract for 24 h before the medium was removed and replaces with fresh medium containing 0.5 mg/mL 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT).The formazan crystals were dissolved in DMSO 4 h later; the absorbance was measured at 570 nm with a Tecan Safire II Reader.
T. b. brucei TC221 cell viability was additionally to the MTT assay confirmed and evaluated using microscopic techniques.
Toxicity of the extracts for T. b. brucei was compared to HeLa and Cos7 cells and the Selectivity index (SI) was calculated.SI: ratio of the IC 50 value of mammalian cells divided by the IC 50 value of trypanosomes.
To test the antiproliferative effect, 5 × 10 3 or 15 × 10 3 cells per well (depending on the cell line) were seeded in 96 well plates and incubated with 5, 10, 25, 50, 100, and 200 µg/mL water extract for 72 h.The cell viability was also determined using the MTT assay with minor modifications.Acute toxicity was similarly measured using MTT assay but after short-term (6 h) incubation with the extracts at the concentrations of IC 50 calculated for each cell line.
To determine the antiviral effect of the extracts, BVDV was used here as a substitute in vitro model for HCV infection.Bovine epithelial cells obtained from embryonic trachea (EBTr) were cultured in MEM with GLUTAMAX medium as described previously [6].They were seeded in 96 well plates (15 × 10 3 cells/well; 50 µL/well) and left to attach for 2 h.Afterwards, the cells were infected with 50 µL/well of the desired dilution in culture medium of an initial suspension of BVDV (cytopathic strain Oregon C24V, genotype I, subgenotype b) to reach 40% cytopathic effect.After 48 h of incubation the medium was replaced with dilutions in culture medium of the extracts (1, 5, 10, 50, 100 μg/mL).The viability of the EBTr cells was measured using the MTT assay after 72 h incubation.
An HBV antiviral assay based on the HepG2 2.2.15 model was used to determine the antiviral activity of the extracts [41].HepG2 2.2.15 cells were seeded in six-wells plates (35 × 10 4 per well) before being incubated for 21 days with 50 µg/mL, 25 µg/mL and 12.5 µg/mL extract.The culture medium was replaced every 3 days with fresh medium, containing the extract dilutions.Quantitative real-time PCR (QPCR) was used to measure the HBV-DNA levels in the culture medium (representing HBV virion production) as described previously [7].Cytotoxicity was determined using the uptake of NR dye at the end of treatment [42].
At least three cultures for each experimental condition were carried out.Data points were obtained in triplicate form (T. b. brucei, cancer cell lines, Cos7, HepG2 2.2.15 cells) and in 8 different wells (EBTr).The IC 50 value was calculated using SigmaPlot ® 11.0 (4 parameter logistic curve).Statistical significance determined via paired t-test or the Bonferroni method of multiple-range testing.

Results and Discussion
The great diversity of natural products occurring plants is of the utmost importance for the discovery of new pharmaceutical lead compounds.Through millions of years of evolution the defence mechanisms of plants were perfected.The great variety of natural products clearly demonstrates the efficacy of this defence strategy against herbivores, but also fungi, bacteria and viruses (Table 2).In many cases the plants do not rely on specific interactions but also rely on unspecific molecules that interact with a great number of targets (Table 1).Of highest importance are the interactions with free amino and free SH groups.While aldehydes, isothiocyanates and epoxids are able to form covalent bonds with free amino groups, sesquiterpene lactones, disulfides, polyacetylenes and epoxides interact with free SH groups.Phenolic OH-groups interact on a non-covalent basis with free amino groups by forming strong hydrogen and ionic bonds.
The cytotoxicity of water and organic solvent extracts from 82 medicinal plants was determined in the fibroblast cells Cos7 and in four cancer cell lines: HeLa, HepG2, SK-Hep1 and LS 174T (Tables 3  and 4).The aqueous extracts were also screened against BVDV and HBV (Table 3), whereas organic solvent extracts were assayed on T. b. brucei (Table 4).Our results revealed promising results in order to use several of these plants as sources for therapeutic agents.
The viral particles offer three main targets to the natural products (Table 1).They can interact with the surface proteins, the biomembrane and the DNA or RNA.While most plants interact unselectively with the virus, selective interactions do also occur.
Among all of them, norcepharadione B has been identified as anti-herpes virus type 1 compound [55], quercetin may reduce virions production of HCV [56], but not against HBV [7] and quercetin 3-rhamnoside may be effective against influenza A virus [57].
The insecticidal properties of diarylheptanoid [71] as well as protective effects on anaphylactic reactions of the aqueous extracts from the fruit of Alpinia oxyphylla [72] have been described in the past.Recently anti-angiogenic properties of the fruit have been also discovered [73].
The water extracts were also screened against HBV in HepG2 2.2.15 cells (Table 3).Evodia lepta, Hedyotis diffusa and several Glycyrrhiza species lowered the HBV-DNA significantly and were not toxic to the HepG2 2.2.15 cell line (Figure 1).Hardly anything is known about the other natural products of Evodia lepta, while the highly bioactive chromenes seem to be among the major constituents [74].Glycyrrhiza species, on the other hand, are well known for their anti-inflammatory effects due to glycyrrhizic acid [9].This genus is also known for its antiviral, especially antihepatitis properties [15,75].Its ability to reduce the HBV-DNA in the culture medium of HepG2 2.2.15 at high doses has been previously reported [7].
Heydiotis diffusa again is a plant rich in iridoid glycosides with anti-inflammatory and hepatoprotective activities [76][77][78].These compounds are most likely to be responsible for the effects against HBV.
Three enterohepatic cancer cell lines, HepG2 and SK-Hep1 (from human hepatoblastoma and hepatocarcinoma) and LS 174T (from human colon adenocarcinoma), were used to determine the antitumor ability of water extracts (Table 3).Twenty extracts were found to induce a significant antiproliferative effect with IC 50 values between 0.5 and 20 µg/mL on these cell lines.These were further investigated to elucidate whether this was due to cytotoxicity.
In HepG2, none of the 4 extracts with ability to inhibit cell growth (Coptis chinensis, Epimedium brevicornum, Equisetum hiemale and Senecio scandens), were found to induce acute cell toxicity when they were incubated with the IC 50 of the extracts for 6 h (Figure 2).In SK-Hep1, among the 10 extracts with antitumor effect 7 did not induce acute toxicity (Arctium lappa, Cassia tora, Centipeda minima, Chrysanthemum indicum, Coptis chinensis, Phellodendron chinense and Rheum palmatum), whereas Dysosma versipellis was especially active by lowering the cell viability in comparison to the control to 40% (Figure 3).This is consistent with the inhibitory effects known for the lignans of D. versipellis against prostate cancer cell lines [79].Evodia lepta and Kadsura longipedunculata lowered also the cell viability of SK-Hep1 in comparison to the control to 50-60%.Recently, it has been reported that the essential oil of Kadsura longipedunculata and its major components (delta-cadinene, camphene, borneol, cubenol, and delta-cadinol) have some degree of cytotoxic activity against some human cell lines [80].In LS 174T cells, water extracts from Coptis chinensis, Dysosma versipellis, Epimedium brevicornum, Hedyotis diffusa and Houttuynia cordata have antiproliferative effects without affecting cell viability (Figure 4), whereas Paeonia lactiflora, Platycladus orientalis, and Polygonum aviculare, in addition to inhibition of cell growth were able to acutely lower cell viability in comparison to the control to 60-70%.Paeonia lactiflora, which belongs to the Paeoniaceae family, is known as one of the richest sources of various resveratrol derivatives [81].These phytoestrogens are known to exert strong antioxidant activity [81] and to inhibit growth of several cancer cell lines [82,83], including a colon human cell line [84].Recently, the antiproliferative effects of essential oils obtained from Platycladus orientalis on human renal adenocarcinoma and amelanotic melanoma cells have been reported [85].
Coptis chinensis, which has been found active against the three enterohepatic cell lines, belongs to TCM formulations commonly used to treat liver diseases associated to infections by gastrointestinal parasite such as Blastocystis hominis [86].Coptisine, which is used as gastric mucosa protector, and berberine, which has very interesting properties as antiinflamatory, antidiabetes, antidiarrhea, and hypocholesterolemic drug, have been obtained from this plant.Both of them have also shown antitumoral activities in in vitro models [87][88][89][90][91][92].
Animal cells offer several targets to natural products (Table 1).Of great importance are the biomembrane, the proteins and the DNA.Since human cells and trypanosomes share many similarities in the structure of the cells, it is extremely important to select those plant extracts where a great selectivity index (SI) occurred.The different cytotoxicity strongly hints to selective interactions between natural products and trypanosomes that do not occur in human cells.A great SI also hints to the relative absence or relative insignificance of general cytotoxic mechanisms like the unspecific interaction of phenolic OH-groups compared to more specific interactions with certain structures in trypanosomes.
The CH 2 Cl 2 and MeOH extracts of 82 medicinal plants were screened against the cell lines HeLa, Cos7 and trypanosomes (T.b. brucei) (Table 4).The SI of the IC 50 of mammalian cell/trypanosomes was regarded as significant if it was over 80.According to this criterium, seven extracts were highly selective towards trypanosomes.
The CH 2 Cl 2 extract of Alpinia oxyphylla showed IC 50 values of 119.6 µg/mL, 30.4 µg/mL and 0.7 µg/mL against HeLa, Cos7 and T. b. brucei respectively with SI of 170 and 43 between HeLa and T. b. brucei and Cos7 and T. b. brucei respectively.The MeOH extract of A. oxyphylla also was effective with IC 50 values of 213.8 µg/mL, 110.2 µg/mL and 2.0 µg/mL against HeLa, Cos7 and T. b. brucei respectively.The SI was 107 and 55 between HeLa and T. b. brucei and Cos7 and T. b. brucei respectively.A. oxyphylla is basically an essential oil plant, so that we suspect the active principle to be based on the sesquiterpenes already known for their cytotoxic properties [93].
For Kadsura longipedunculata only the CH 2 Cl 2 extract exhibited a significant selectivity.Here, the IC 50 values of HeLa, Cos7 and T. b. brucei were 9.9 µg/mL, 1.8 µg/mL and 0.1 µg/mL respectively, resulting in SI of 99 and 18 between HeLa and T. b. brucei and Cos7 and T. b. brucei respectively.Essential oil and lignans form the major natural compounds of K. longipedunculata [80,94].The specific trypanocidal effect rather seems to be based on the lignans than on the more unspecific essential oil.Further studies would be necessary to confirm this assumption.
For Arctium lappa only the CH 2 Cl 2 extract showed a significant selectivity with IC 50 values of 345.0 µg/mL, 344.2 µg/mL and 3.6 µg/mL against HeLa, Cos7 and T. b. brucei respectively and SI of 96 between HeLa and T. b. brucei and Cos7 and T. b. brucei.
In Panax ginseng and P. notoginseng the selectivity was again limited to the CH 2 Cl 2 extract.The trypanocidal effects of A. lappa, P. ginseng, P. notoginseng and S. divaricata are based on the presence of highly reactive polyacetylenes, especially panaxynol.
Only the methanolic extract of Coptis chinensis showed a significant selectivity, but not the dichloromethane extract.The IC 50 values of 81.8 µg/mL, 3.7 µg/mL and 0.4 µg/mL against HeLa, Cos7 and T. b. brucei respectively gave SI of 205 and 9 between HeLa and T. b. brucei and Cos7 and T. b. brucei respectively.Our analytical data confirmed berberine as the main alkaloid of C. chinensis.The toxicity of C. chinensis is probably an effect of the DNA intercalation of its alkaloids into the DNA double helix of T. b. brucei [95,96].
The trypanocidal effect of berberine against different trypanosoma species has been demonstrated previously.Merschjohann et al. [97] showed that T. congolense are sensitive to berberine at concentrations of 83 µM, while Rosenkranz and Wink [98] demonstrated a sensitivity of T. brucei to berberine at concentrations of only 0.5 µM.Recently, the effect of berberine against T. rhodesiense was also established by Freiburghaus et al. [99].T. rhodesiense was sensitive to 4.2 µg/mL.The significant differences in sensitivity of different trypanosoma species to berberine could be of high interest regarding resistance mechanisms against mutagenic compounds.Berberine might due to its mutagenic activity never become a lead structure for the development of trypanocidal drugs, but the differences in sensitivity of these three trypanosoma species might help to understand defence mechanisms against DNA intercalating substances.

Conclusions
Traditional Chinese and European Medicine comprise promising plants that might be used for antiviral, antitrypanosomal and anticancer therapy.The promising discoveries of highly effective plants against viral hepatitis, trypanosomiasis and liver and intestinal cancer cells, however, require further research to establish new lead structures or their combinations for the treatment of these important traditional diseases.

Financial Support
This study was supported in part by the Ministerio de Ciencia y Tecnología, Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica (Grant SAF2010-15517), Spain.

Figure 1 .
Figure 1.Effect of water extracts on hepatitis B virus (HBV) release as determined by HBV-DNA content in the culture medium and cell viability as determined by Neutral Red uptake by human hepatoblastoma cells HepG2 2.2.15 infected with Values are means ± SD of three experiments carried out in triplicate by incubation with the extracts for 21 days.*, p < 0.05 as compared with untreated cells by paired t-test.

Figure 3 .
Figure 3. Acute cell toxicity as determined by MTT assay in human hepatoma SK-Hep1 cells.Values are means ± SD of four experiments carried out in triplicate.*, p < 0.05 as compared with Control by the Bonferroni method of multiple range testing.

Figure 4 .
Figure 4. Acute cell toxicity as determined by MTT assay in human colon adenocarcinoma LS 174T cells.Values are means ± SD of four experiments carried out in triplicate.*, p < 0.05 as compared with Control by the Bonferroni method of multiple range testing.

P
. ginseng gave IC 50 values of 152.4 µg/mL, 47.7 µg/mL and 0.9 µg/mL against HeLa, Cos7 and T. b. brucei respectively with SI of 169 and 53 between HeLa and T. b. brucei and Cos7 and T. b. brucei respectively.P. notoginseng demonstrated IC 50 values of 263.0 µg/mL, 6.4 µg/mL and 0.9 µg/mL with SI of 292 and 7 between HeLa and T. b. brucei and Cos7 and T. b. brucei respectively.Also an extremely active plant was Saposhnikovia divaricata.Here as well, lipophilic CH 2 Cl 2 extract was selective with IC 50 values of 410.1 µg/mL, 45.9 µg/mL and 5.1 µg/mL against HeLa, Cos7 and T. b. brucei respectively and SI of 80 and 9 between HeLa and T. b. brucei and Cos7 and T. b. brucei respectively.

Table 3 .
Cytotoxicity against cancer cells, Cos7 fibroblasts, and antiviral activity against HBV and flaviviruses of water extracts obtained from 82 medicinal plants.

Table 4 .
Cytotoxicity against HeLa cancer cells, Cos7 fibroblasts and Trypanosoma brucei brucei of organic extracts obtained from 82 medicinal plants.