Screening of several Indonesian medicinal plants for their inhibitory effect on histamine release from RBL-2H3 cells

Twelve alcoholic extracts and 12 hexane extracts of plant materials selected on the basis of medicinal folklore for asthma treatment in Indonesia were studied for their activity in inhibiting histamine release from RBL-2H3 cells (rat basophilic leukemia cell line), a tumor analog of mast cells. The results of screening indicated that five alcoholic extracts (Plantago major leaves, Eucalyptus globulus leaves and fruit, Cinnamomum massoiae cortex, Vitex trifolia leaves) and two hexane extracts (Eucalyptus globulus leaves, Vitex trifolia leaves) inhibited IgE-dependent histamine release from RBL-2H3 cells. The inhibitory effects were found to be more than 80% for extract concentrations of 0.5 mg/ml. The results indicate that the extracts contain active compounds that inhibit mast-cell degranulation, and provide insight into the development of new drugs for treating asthma and/or allergic disease.     

Comparative evaluation of wound healing potency of Vitex trifolia L. and Vitex altissima L

The wound healing potency of ethanol leaf extracts of V. trifolia L. and V. altissima L. was evaluated in excision, incision and dead space wound models. Both plants were found to possess significant wound healing activity which was evidenced by a decrease in the period of epithelialization, an increase in the rate of wound contraction, skin breaking strength, granulation tissue dry weight, hydroxyproline content and breaking strength of granulation tissue. Histopathological study of the granulation tissue also showed an increased collagenation when compared with the control group of animals. Of the two extracts, the ethanol leaf extract of V. trifolia showed maximum wound healing activity compared with the leaf extract of V. altissima. However, on comparison with the control group, both leaf extracts were found to possess significant wound healing potency.     

Antiparasitic activity of some New Caledonian medicinal plants

Twenty-nine extracts of 18 medicinal plants used in New Caledonia by traditional healers to treat inflammation, fever and in cicatrizing remedies were evaluated in vitro against several parasites (Leishmania donovani, Trypanosoma brucei brucei, Trichomonas vaginalis and Caenorhabditis elegans). Among the selected plants, Scaevola balansae and Premna serratifolia L. were the most active against Leishmania donovani with IC(50) values between 5 and 10microg/ml. The almond and aril extracts from Myristica fatua had an IC(50) value of 0.5-5microg/ml against Trypanosoma brucei brucei. Only Scaevola balansae extract presented a weak activity against Trichomonas vaginalis. The almond extract from Myristica fatua presented significant activity against Caenorhabditis elegans (IC(50) value of 6.6+/-1.2microg/ml).     

Antileishmanial and antifungal activity of plants used in traditional medicine in Brazil

The antileishmanial and antifungal activity of 24 methanol extracts from 20 plants, all of them used in the Brazilian traditional medicine for the treatment of several infectious and inflammatory disorders, were evaluated against promastigotes forms of two species of Leishmania (L. amazonensis and L. chagasi) and two yeasts (Candida albicans and Cryptococcus neoformans). Among the 20 tested methanolic extracts, those of Vernonia polyanthes was the most active against L. amazonensis (IC(50) of 4 microg/ml), those of Ocimum gratissimum exhibited the best activity against L. chagasi (IC(50) of 71 microg/ml). Concerning antifungical activity, Schinus terebintifolius, O. gratissimum, Cajanus cajan, and Piper aduncum extracts were the most active against C. albicans (MIC of 1.25 mg/ml) whereas Bixa orellana, O. gratissimum and Syzygium cumini exhibited the best activity against C. neoformans (MIC of 0.078 mg/ml).     

Antimalarial activity of medicinal plants used in traditional medicine in S. Tomé and Príncipe islands

The present study investigates the antimalarial activity of 13 medicinal plants used in traditional medicine in S. Tomé and Príncipe (STP) islands in the Gulf of Guinea, aiming at identifying the most effective plants for further research. Fieldwork was carried out with the collaboration of 37 traditional healers from both islands, during an ethnobotanical study, which was conducted from 1993 to 1999. Our results indicate that the traditional healers in STP use several medicinal plants against fever and/or 'malaria' which reveal strong antiparasitic activity in vitro: four of the plant extracts have evident antiplasmodial activity against chloroquine resistant Plasmodium falciparum, with IC(50) values <10 microg/ml, and also revealed hepatic schizontocidal activity (<5-35 microg/ml). In vivo, the extracts caused partial reduction of Plasmodium berghei parasitaemia in mice.     

Screening for anti-infective properties of several medicinal plants of the Mauritians flora

Several plants of the Mauritian flora alleged to possess anti-infective properties were studied against different strains of pathogenic bacteria and fungi. The grounded dried plant materials were extracted with different extractants and screened for anti-microbial activity using the disk diffusion and the micro-dilution techniques. Preliminary screening revealed that the methanol extracts were most active. Salmonella enteritidis, Enterobacter cloacae and Bacillus subtilis were the three test organisms, which were found to be susceptible to all the crude methanolic extracts of the different plants investigated (100% susceptibility), followed by Escherichia coli (57.1%) and Pseudomonas aeruginosa (57.1%), and Staphylococcus aureus (28.6%). The lowest minimum inhibitory concentration recorded for the different crude methanol extracts against Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, Enterobacter cloacae, Bacillus subtilis and the mould fungus Candida albicans were 500, 1000, 125, 250, 1000 and 125 micro g/ml, respectively. Bioautography using Cladosporium cucumerinum revealed that dichloromethane (DCM) extracts had the highest activity against the phytopathogenic fungus. It was also noted that the DCM extracts of Michelia champaca and Antidesma madagascariense yielded the maximum number of growth inhibiting compounds against Cladosporium cucumerinum. Activity of the different crude extracts was also investigated against several phytopathogenic filamentous fungi, Colletotrichum glocosporoides, Rhizoctonia solani, Sclerotinia sclerotium, Guignardia sp. and Fusarium oxysporum. It was found that crude hexane extracts as well as crude DCM extracts exhibited marked activity against several strains of fungi, especially Colletotrichum glocosporoides, Sclerotinia sclerotium and Guignardia sp.     

Cytotoxic metabolites from the fungal endophyte Alternaria sp. and their subsequent detection in its host plant Polygonum senegalense

From the Egyptian medicinal plant Polygonum senegalense the fungal endophyte Alternaria sp. was isolated. Extracts of the fungus grown either in liquid culture or on solid rice media exhibited cytotoxic activity when tested in vitro against L5178Y cells. Chromatographic separation of the extracts yielded 15 natural products, out of which seven were new compounds, with both fungal extracts differing considerably with regard to their secondary metabolites. Compounds 1, 2, 3, 6, and 7 showed cytotoxic activity with EC 50 values ranging from 1.7 to 7.8 microg/mL. When analyzed in vitro for their inhibitory potential against 24 different protein kinases, compounds 1- 3, 5- 8, and 15 inhibited several of these enzymes (IC 50 values 0.22-9.8 microg/mL). Interestingly, compounds 1, 3, and 6 were also identified as constituents of an extract derived from healthy leaves of the host plant P. senegalense, thereby indicating that the production of natural products by the endophyte proceeds also under in situ conditions within the plant host.     

In vitro Activity of Extracts from Polyporaceae against Human Immunodeficiency Virus Type 1

Aqueous extracts of Fomitella supina, Phellinus rhabarbarinus, Trichaptum perrottettii, and Trametes cubensis (Polyporaceae) from the Amazonian rain forest of Venezuela exhibited differential cytotoxicity and inhibitory activity against the human immunodeficiency virus type 1 (HIV-1). These extracts inactivated extracellular virions and suppressed HIV-1 replication by blocking HIV-1-induced cell–cell fusion in an in vitro culture system. They also stimulated interferon (IFN) production, active against HIV-1 and vesicular stomatitis virus (VSV) cytopathic effects. The results suggest that these extracts contain novel anti-HIV active compounds which, individually or in combination, can exert several distinct suppressive effects. The test extracts appear to act specifically at the level of CD4-gp120 binding.     

Antipyretic studies on some indigenous Pakistani medicinal plants: II

Eight Pakistani medicinal plants were investigated for antipyretic activity in rabbits receiving subcutaneous yeast injections. Hexane- and chloroform-soluble extracts of Aconitum napellus stems, Corchorus depressus whole plant and Gmelina asiatica roots exhibited prominent oral antipyretic activity while insignificant antipyretic effects were found in the hexane- and chloroform-soluble portions of Melia azadirachta seeds, Tinospora cordifolia stems and Vitex trifolia seeds. No antipyretic actions whatsoever were produced by extracts of A. heterophyllum roots and Hedysarum alhagi aerial parts. Toxicity studies revealed no noteworthy toxic or adverse effects for any of the above plant extracts up to the highest oral doses of 1.6 g/kg except in the case of A. napellus.     

Antimicrobial activity of selected Peruvian medicinal plants

The antimicrobial activity of 36 ethanol extracts from 24 plants, all of them currently used in the Peruvian traditional medicine for the treatment of several infectious and inflammatory disorders, was tested by means of the agar-well diffusion assay against four bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) and four fungi (Candida albicans, Trichophyton mentagrophytes, Microsporum gypseum and Sporothrix schenckii). Twenty-five (69%) extracts showed some degree of antimicrobial activity against at least one microorganism. The plants with the greatest antimicrobial activity were Cestrum auriculatum L. Heritier (Solanaceae), Iryanthera lancifolia Ducke Suesseng (Myristicaceae), Lepechinia meyenii (Walp.) Epling (Lamiaceae) and Ophryosporus peruvianus (Gmelin) King & H. Rob. (Asteraceae).     

Protective effect of Sargassum polycystum (brown alga) against acetaminophen-induced lipid peroxidation in rats

Lipid peroxidation is believed to play an important role in the pathogenesis of several diseases, such as cancer, diabetic mellitus and liver injury. Aqueous and ethanol extracts of Sargassum polycystum C. Agardh (Phaeophyta) were screened for their protective effects against acetaminophen (ACP; Paracetamol)-induced lipid peroxidation in rats. A single dose of acetaminophen significantly elevated the levels of lipid peroxides (LPO) with decreased levels of free radical scavenger enzymes (SOD, CAT, GSH, GPx, GST) in liver homogenate. The oral pretreatment of rats with ethanol and aqueous extracts of Sargassum polycystum C. Agardh (100 mg, 200 mg[sol ]kg body wt[sol ]day respectively, for a period of 15 days) significantly reduced the acetaminophen-induced oxidative stress in rats. The animals treated with the ethanol and aqueous extracts alone did not show any toxicity on liver tissue. This observation shows that the seaweed crude extracts probably acted to protect against acetaminophen-induced lipid peroxidation through their free radical scavenging property.     

Anti-diarrhoeal evaluation of some medicinal plants used by Zulu traditional healers.

Aqueous and methanolic extracts of several medicinal plants, Psidium guajava (leaves), Aristea spp., Iridaceae family (stem), Bridelia micrantha (bark) and Eleutherina bulbosa (bulb), used by Zulu traditional healers were evaluated for anti-diarrhoeal activity against different experimental models of diarrhoea in rats as well as for anti-microbial activity against different pathogenic microorganisms that cause diarrhoea. The methanolic extract of P. guajava (leaves) was the only agent showing significant inhibitory activities against the growths of Salmonella spp. (two isolates), Shigella spp. (S. flexneri, S. virchow and S. dysenteriae) and enteropathogenic Escherechia coli (two isolates). The methanolic extract of B. micrantha (Bark) demonstrated weak inhibitory activities against S. flexneri and S. plesiomonas. Based on the results in experimental rat models, there were significant reductions in faecal output and frequency of droppings when plant extracts were administered compared with castor-oil treated rats. All plant extracts also significantly retarded the propulsion of charcoal meal and significantly inhibited the PGE(2)-induced enteropooling. The results have confirmed the effectiveness of all these Zulu medicinal plants as anti-diarrhoeal agents.     

In vitro inhibition of mycobacteria by Rwandese medicinal plants

A series of 15 Rwandese medicinal plants used by traditional healers to treat pulmonary diseases were screened for anti-Mycobacterium tuberculosis activity. Three plant extracts showed activity at 1000 μg/mL: Bidens pilosa (leaves), Pentas longiflora (roots) and Tetradenia riparia (leaves). These plant extracts were studied further against several mycobacterial species: M. tuberculosis, M. avium complex, M. simiae and a new simiae like Mycobacterium species (SLM). None of the plant extracts showed activity against M. avium and SLM at 1000 μg/mL. M. simiae was sensitive to T. riparia and P. longiflora extracts (1000 μg/mL) and M. tuberculosis towards T. riparia (500 μg/mL) and B. pilosa (100 μg/mL). The active principle of T. riparia, 8(14), 15-sandaracopimaradiene-7α, 18-diol, was also evaluated for its antimycobacterial activity and the concentration required for inhibiting M. tuberculosis ranged from 25 μg/mL to 100 μg/mL. The extract of the leaves of T. riparia can be used as a differentiation test (at 1000 μg/mL in the medium) for M. simiae and SLM.     

Evaluation of the antimicrobial potential of medicinal plants from the Ivory Coast

A total of 148 crude ethanol extracts from 115 plant species were tested in vitro against Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa) and the Gram-positive Staphylococcus aureus and Enterococcus faecalis. Moreover, they were submitted to antifungal assays against Candida albicans and Cladosporium cucumerinum, a human and a plant pathogenic microorganism, respectively, known to be good indicators of antifungal activity. No activity was detected against the Gram-negative bacteria, while 14.8% and 10.8% of the extracts showed Gram-positive bactericidal or bacteriostatic effects on S. aureus and E. faecalis, respectively. An antifungal activity was observed with 15 extracts (10.1%). Two species were particularly active against the fungi: Dioscorea minutiflora and Erythrina vogelii. The young tubers of D. minutiflora contain metabolites with a specific effect on fungi and were not active against the bacteria. On the other hand, E. vogelii was highly effective against the Gram-positive bacteria and the fungi.     

Some South African Rubiaceae Tree Leaf Extracts Have Antimycobacterial Activity Against Pathogenic and Non‐pathogenic Mycobacterium Species

Tuberculosis (TB) caused by Mycobacterium tuberculosis remains an ongoing threat to human health. Many plant species contain antimycobacterial compounds, which may serve as template molecules for new anti‐TB drugs. The Rubiaceae family is the largest family of trees in southern Africa, and preliminary evidence revealed antimycobacterial activity in several species of the genus, motivating further studies. Leaf extracts of 15 tree species from the Rubiaceae family were screened for antimycobacterial activity against pathogenic M. tuberculosis and non‐pathogenic Mycobacterium smegmatis, Mycobacterium aurum and Mycobacterium bovis BCG (Bacillus Calmette‐Guérin) using a twofold serial microdilution assay. Cytotoxicity was determined using a tetrazolium‐based colorimetric assay against C3A liver cells and Vero kidney cells. Minimum inhibitory concentration values as low as 0.04 mg/mL against M. smegmatis and M. tuberculosis were recorded. Activity against M. aurum was the best predictor of activity against pathogenic M. tuberculosis (correlation coefficient = 0.9). Bioautography indicated at least 40 different antimycobacterial compounds in the extracts. Cytotoxicity of the extracts varied, and Oxyanthus speciosus had the most promising selectivity index values. Copyright © 2015 John Wiley & Sons, Ltd.     

Virucidal activity in aqueous extracts obtained from Cedrela tubiflora leaves

Crude extracts obtained from leaves of Cedrela tubiflora (CT) (Meliaceae family) show antiviral and virucidal effects against several viruses. Herpes simplex, pseudorabies and vesicular stomatitis viruses were extremely susceptible and a reduction of 3–5 log in infectivity occurred after 15 min of direct incubation with the plant extract. By contrast, poliovirus and the Tacaribe arenavirus are inhibited intracellularly. The inhibitory action is dose dependent and no cytotoxic effects were detected on Vero cells after 2 days of CT treatment.     

Some pharmacological properties of extracts of Terminalia sericea roots

Terminalia sericea Burch. Ex. DC (Combretaceae) extracts are used to treat bacterial infections, diarrhea, and diabetes. Intermediate and polar extracts of the roots exhibited antibacterial activity against Staphylococcus aureus, Escherichia coli, Bacillus anthracis, and Pseudomonas aeruginosa, while the petroleum ether extract was inactive. The extracts were mildly active against Bacillus anthracis and Pseudomonas aeruginosa but exhibited the highest activity against Staphylococcus aureus. They also exhibited antifungal activity against Candida albicans and Aspergillus niger. An 80% aqueous ethanol extract of the roots did not have any effect on blood glucose levels during an oral glucose tolerance test (OGTT), in mice (P>0.05). With the exception of the dichloromethane and petroleum ether extracts, all the intermediate and polar extracts were toxic to brine shrimps giving LC(50) (95% confidence intervals) values ranging from 5.4 (3.5-8.4) to 17.4 (11.4-26.5) microg/ml, while that of cyclophosphamide, a standard anticancer drug, was 16.3 (10.6-25.2) microg/ml. Further work is in progress to isolate and identify active compounds in the extracts.     

In vitro evaluation of the amebicidal activity of Buddleia cordata (Loganiaceae, H.B.K.) on several strains of Acanthamoeba.

Infectious diseases produced by free-living amoebae from the genus Acanthamoeba have been recently recognized. The need for antiamebic compounds is urgent as the occurrence of these diseases is being registered more frequently since the late sixties. We screened the aqueous and methanolic extract of a plant used by folk medicine (Buddleia cordata) against eye and skin inflammation for antiamebic activity. We tested the extracts on 29 strains of free-living amoebae, with the result that they were amebostatic for 14 and 15 strains, respectively. We obtained linarin and vanillic acid from the extracts, but only linarin was amebostatic to all the strains and vanillic acid had no activity. However, acetyl vanillic acid had similar effects on amoebae to linarin. Threshold values of these two active compounds ranged from 31.25 microg/ml to 4 mg/ml and from 31.25 microg/ml to 8 mg/ml for linarin and acetyl vanillic acid, respectively. These differences in threshold values were observed even on several strains belonging to the same species (as in the case of A. castellanii and A. polyphaga) indicating the need of susceptibility testing for each clinical isolate of free-living amoebae.     

Antioxidant, antimicrobial and cytotoxic activities of selected medicinal plants from Yemen

Ninety crude extracts, including dichloromethane, methanol and aqueous extracts from 30 medicinal plants used in the Yemeni ethnomedicine to treat common infections, were screened in vitro for antimicrobial activities against three Gram-positive bacteria and two Gram-negative bacteria, Candida maltosa and five opportunistic human fungal pathogens (two yeasts, three hyphomycetes). Most of the plants showed antibacterial activities. Extracts from Tamarindus indica flowers and Ficus vasta fruits have been the most active. Of the 30 plants tested, 13 showed antifungal activity (40%) against one ore more human pathogenic fungi. The strongest inhibition was exhibited by Azima tetracantha (fruits), Sansevieria ehrenbergii (fruits) and Solanum incanum (fruits). Ten methanol extracts, especially those of Acacia asak barks and Solanum nigrum fruits, showed effective free radical scavenging activities in the DPPH assay. Remarkable cytotoxic activity against FL-cells was shown only for five plants, among them Plicosepalus curviflorus (stems).     

Cytotoxic activity of selected plants used as antitumorals in Mexican traditional medicine

Crude extracts from nine plants widely used in Mexican traditional medicine for the treatment of cancer have been subjected to a bioscreening study to detect cytotoxic activity against human tumor cells. Three different extracts (petroleum ether, ethylacetate, and methanol) from each plant species, were tested towards KB, HCT-15 COLADCAR and UISO-SQC-1 cell cultures. The results showed that three plants Colubrina macrocarpa (Cav.) Don (Rhamnaceae), Acacia pennatula (Schltdl. and Cham.) Benth (Leguminosae) and Hemiangium excelsum (HBK.) Smith (Hippocrateaceae), exhibited important cytotoxic activity showing a certain degree of selectivity against the tested cells in culture.