A comparative study of the antimicrobial and phytochemical properties between outdoor grown and micropropagated Tulbaghia violacea Harv. plants

Aim of the study

The study aimed to compare the antimicrobial and phytochemical properties of in vitro cultured and outdoor grown Tulbaghia violacea plants in the quest to validate the use of micropropagated plants as alternatives to outdoor grown plants in traditional medicine. Tulbaghia violacea is used extensively in South African traditional medicine for HIV/AIDS patients and in the treatment of gastrointestinal ailments, asthma, fever and tuberculosis.

Materials and methods

Extracts of micropropagated and outdoor grown Tulbaghia violacea plants were evaluated for their antibacterial and antifungal activities against Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and a fungus Candida albicans using microdilution methods. Saponins and phenolic compounds including condensed tannins, gallotannins and flavonoids were quantitatively determined using spectrophotometric methods. A qualitative test for saponins was also carried out.

Results

The petroleum ether (PE) extracts of micropropagated plants and dichloromethane (DCM) extracts of outdoor grown plants showed good antibacterial activity, each against two bacterial test strains. PE extracts of micropropagated plants showed the best antibacterial activity with a minimum inhibitory concentration (MIC) of 0.39 mg/ml against Bacillus subtilis. Good MIC (<1 mg/ml) and minimum fungicidal concentration (MFC) values of 0.78 mg/ml were only obtained in DCM extracts of outdoor grown plants. MIC and MFC values for water and ethanol extracts of both micropropagated and outdoor grown plants were similar and in the range 3.125-12.5 mg/ml. Total phenolics, gallotannins, flavonoids and saponins were significantly higher in micropropagated plants than in outdoor grown ones. In all cases, the amounts of phytochemical compounds in micropropagated plants were more than twice that of outdoor grown plants except for condensed tannins.

Conclusion

The results form a good basis for the use of Tulbaghia violacea micropropagated plants as a complement to the outdoor grown plants in traditional medicine.     

Pharmacological, genotoxic and phytochemical properties of selected South African medicinal plants used in treating stomach-related ailments

Ethnopharmacological relevance

The evaluated medicinal plants are used in South African traditional medicine in treating stomach-related ailments.

Aims of the study

The study aimed at evaluating the pharmacological, genotoxic and phytochemical properties of the seven selected medicinal plants used for treating stomach-related ailments.

Materials and methods

: Ethyl acetate (EtOAc), ethanol (EtOH) 70% and water extracts of the selected plant parts were evaluated for their antimicrobial and anthelmintic activities using microdilution assays. Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus), Gram-negative bacterium (Escherichia coli) and Candida albicans were used for antimicrobial assays. Caenorhabditis elegans was used for the anthelmintic assay. Plant extracts were also assayed for their cyclooxygenase-inhibitory activity against cyclooxygenase-1 and -2 enzymes. The Ames test was used to evaluate the genotoxicity of the plant extracts. A spectrophotometric method was used to determine the total phenolics, gallotannins, flavonoids and saponins.

Results

Twelve extracts exhibited minimum inhibitory concentration (MIC) <1 mg/mL against the bacterial test strains, and five extracts exhibited MIC <1 mg/mL against Candida albicans. The EtOAc extract of Tetradenia riparia had the best minimum lethal concentration (MLC) value (0.004 mg/mL) against Caenorhabditis elegans. All the EtOAc extracts exhibited percentage inhibition in the range of 50.7-94.7% against COX-1 and -2 enzymes at 250 μg/mL. All the plant extracts were non-mutagenic towards Salmonella typhimurium tester strains TA98, TA100 and TA1537 without metabolic activation. Phytochemical analysis revealed relatively high amounts of total phenolics, gallotannins and flavonoids in the evaluated plant extracts.

Conclusions

The general pharmacological activities exhibited by some of the plant extracts in this study support the traditional uses of the selected plants in treating stomach-related ailments. The Ames test showed that all the plant extracts were non-mutagenic but cytotoxicity tests are needed to ascertain the safety for long-term consumption.     

Ethnopharmacological survey and in vitro evaluation of wound-healing plants used in South-western Nigeria

Ethnopharmacological relevance

Traditional healers in Nigeria employ a range of plant preparations as wound healing agents. Despite the use of local plants in wound healing, there is only scant literature on the wound healing properties of these plants to support the continued therapeutic application of these herbal remedies.

Aim of the study

To document plants commonly used to treat wounds in South-western Nigeria and to test the scientific basis of such claims using relevant in vitro tests.

Materials and methods

Structured questionnaires were used to determine which plant preparations are in common use, via interviews with Yoruba traditional healers. Aqueous and ethanolic extracts of the nine most common plants cited by the healers were collected, identified and tested using relevant in vitro wound healing assays. Minimum inhibitory concentrations (MIC) were determined against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis. Antioxidant activity was measured by DPPH assay and fibroblast proliferation determined by neutral red assay.

Results

A total of 20 traditional healers from South-western Nigeria were involved in the study. Thirty-six plant species were recorded with their local names and parts used in the traditional wound healing preparations. Ethanolic extracts of nine species most frequently cited by the healers exhibited strong antioxidant activities (3.8-31.3 μg/ml) comparable to ascorbic acid (7.3 μg/ml). Crude extracts of the selected plants also inhibited the growth of bacteria with MIC values 0.3-7.6 mg/ml. Ethanol extracts of Bridelia ferruginea Benth. (1-30 μg/ml) and Parkia biglobosa Jacq. (15-30 μg/ml) influenced the proliferation of dermal fibroblasts significantly (p < 0.05). Extracts from the remaining seven plants either had no effect on fibroblast proliferation or were cytotoxic.

Conclusion

Traditional use of many wound-healing plants from Nigeria can be rationalised by activity determined in relevant in vitro investigations of ethanol and aqueous extracts. These results support the traditional selection of these plants in South-western Nigeria for wound healing.     

Minimum inhibitory concentrations of medicinal plants used in Northern Peru as antibacterial remedies

Aim

The plant species reported here are traditionally used in Northern Peru to treat bacterial infections, often addressed by the local healers as “inflammation”. The aim of this study was to evaluate the minimum inhibitory concentration (MIC) of their antibacterial properties against Gram-positive and Gram-negative bacteria.

Materials and methods

The antimicrobial activity of ethanolic and water extracts of 141 plant species was determined using a deep-well broth microdilution method on commercially available bacterial strains.

Results

The ethanolic extracts of 51 species inhibited Escherichia coli, and 114 ethanolic extracts inhibited Staphylococcus aureus. In contrast, only 30 aqueous extracts showed activity against Escherichia coli and 38 extracts against Staphylococcus aureus. The MIC concentrations were mostly very high and ranged from 0.008 to 256 mg/ml, with only 36 species showing inhibitory concentrations of <4 mg/ml. The ethanolic extracts exhibited stronger activity and a much broader spectrum of action than the aqueous extracts. Hypericum laricifolium, Hura crepitans, Caesalpinia paipai, Cassia fistula, Hyptis sidifolia, Salvia sp., Banisteriopsis caapi, Miconia salicifolia and Polygonum hydropiperoides showed the lowest MIC values and would be interesting candidates for future research.

Conclusions

The presence of antibacterial activity could be confirmed in most species used in traditional medicine in Peru which were assayed in this study. However, the MIC for the species employed showed a very large range, and were mostly very high. Nevertheless, traditional knowledge might provide some leads to elucidate potential candidates for future development of new antibiotic agents.     

Antimycobacterial evaluation and preliminary phytochemical investigation of selected medicinal plants traditionally used in Mozambique

Ethnopharmacological relevance

Several medicinal plants are traditionally used in Mozambique to treat tuberculosis and related symptoms.

Aims of the study

It was aimed to assess the in vitro antimycobacterial activity of crude extracts from fifteen medicinal plants and to reveal main classes of compounds which may account for the activity of extracts.

Methods and materials

The plant materials were sequentially extracted by n-hexane, dichloromethane, ethyl acetate, and 70% ethanol. Decoction of each plant material was also prepared according to traditional use. Broth microdilution method was employed to screen extracts against two mycobacterial species: Mycobacterium smegmatis ATCC 607 and Mycobacterium tuberculosis H37Rv. The extracts with minimum inhibitory concentration(s) (MIC) below 125 μg/mL were considered active and further tested against different mycobacterial species and strains, namely Mycobacterium tuberculosis H37Ra, Mycobacterium bovis BCG ATCC 35734, Mycobacterium smegmatis mc² 155, Mycobacterium avium DSM 44156 and DSM 44157. Cytotoxic effect was evaluated against human macrophages from the monocytic THP-1 cells. Main classes of compounds in these active extracts were proposed from their ¹H NMR spectroscopic characterizations.

Results

n-Hexane extracts of Maerua edulis and Securidaca longepedunculata, ethyl acetate extract of Tabernaemontana elegans and dichloromethane extract of Zanthoxylum capense were found to possess considerable activity against Mycobacterium bovis BCG and Mycobacterium tuberculosis H37Ra with MIC 15.6-62.5 μg/mL. Tabernaemontana elegans ethyl acetate extract displayed strong activity against Mycobacterium tuberculosis H37Rv (MIC 15.6 μg/mL). Except for Tabernaemontana elegans ethyl acetate extract which presented potent cytotoxic effects in THP-1 cells (IC₅₀ < 4 μg/mL), the other three plant extracts showed moderate to none toxicity. Based on ¹H NMR spectroscopic analysis, major components in both Maerua edulis and Securidaca longepedunculata n-hexane extracts were linear chain unsaturated fatty acids. Zanthoxylum capense dichloromethane extract contained more complex constituents (mostly phenolic compounds). In the most potent extract, Tabernaemontana elegans ethyl acetate extract, the prominent compounds were identified as indole alkaloids.

Conclusions

The pronounced antimycobacterial activity of the medicinal plants Maerua edulis, Securidaca longepedunculata, Zanthoxylum capense, and Tabernaemontana elegans suggested that they might provide compounds which could be potential anti-TB drug leads.     

Pharmacological properties of Anagallis arvensis L. ("scarlet pimpernel") and Anagallis foemina Mill. ("blue pimpernel") traditionally used as wound healing remedies in Navarra (Spain)

Ethnopharmacological relevance

: Anagallis arvensis and Anagallis foemina are traditionally used in Navarra (Spain) for dermatological purposes regarding wound healing properties. In some cases they are also used to threat internal infections although they are known to be toxic at high doses.

Aim of study

: Due to lack of studies, we decided to evaluate the potential of the plants as wound healing remedies measuring antimicrobial and anti-inflammatory properties using in vitro procedures.

Materials and methods

Antimicrobial effects were studied against four bacteria and one fungus. Anti-inflammatory properties were measured in terms of COX-1 and -2 inhibition as well as superoxide radical scavenging capacity.

Results

Both species exerted antimicrobial and anti-inflammatory effects. The methanolic extract obtained from Anagallis arvensis seemed to produce the highest inhibition in Candida albicans (MIC = 0.31 mg/ml). Inhibition of COX-1 and -2 was also stronger for methanolic extracts whereas aqueous were revealed as better free radical scavengers.

Conclusions

The study reveals that both species posses antimicrobial and anti-inflammatory activities related to their ethnomedicinal uses.     

Proliferative effects of five traditional Nigerian medicinal plant extracts on human breast and bone cancer cell lines

Ethnopharmacological relevance

The medicinal plants Hunteria umbellata (HUL), Cola lepidota (CCL), Persea americana leaf (PAL), Root bark of Persea americana (RPA) and Plukenetia conophora (PCL) are used in Nigerian traditional medicine for the treatment of cancer and cancer related diseases.

Aim of the study

To scientifically evaluate the cell proliferative and apoptotic effects of the plants extracts using breast and osteocarcinoma cell lines, and also to identify the possible components via LC-MS to have a kind of chemical fingerprint.

Materials and methods

The antiproliferative and apoptotic effects of methanolic extracts (10 μg/ml) of the five medicinal plants were subjected to in vitro evaluation using four cancer cell lines (breast-MCF-7 and BT-20; Osteocarcinoma-MG-63 and Saos-2) measured by flow cytometry. Non-tumorigenic controls MCF-12A and primary isolated osteoblasts (POB) were chosen to eliminate negative influence on healthy tissue.

Results

Of the five extracts RPA demonstrated a significant (P < 0.05) anti-proliferative activity against estrogen receptor positive breast cancer cell lines (MCF-7). The proliferative phase was decreased by 18%, whereas, a significant increase in cell proliferation (about 27%) was observed for RPA at a concentration of 10 μg/ml. PCL, CCL, HUL and PAL did not show marked inhibition of the proliferation of cell line MCF-7.

Conclusion

These results give suggestive evidence that the plant extracts exhibit some correlation between the claimed ethnomedicinal uses and the cell proliferative activity. RPA extract includes chemical compounds with estrogen-like activity and validates its potential use as anticancer agent, particularly against breast carcinoma; provided important information potentially helpful in drug designing and discovery. Further studies will involve the isolation of anti tumour compounds in RPA by LC-MS and detailed mechanism of anticancer activities.     

Kaempferia parviflora, a plant used in traditional medicine to enhance sexual performance contains large amounts of low affinity PDE5 inhibitors

Aim of the study

A number of medicinal plants are used in traditional medicine to treat erectile dysfunction. Since cyclic nucleotide PDEs inhibitors underlie several current treatments for this condition, we sought to show whether these plants might contain substantial amounts of PDE5 inhibitors.

Materials and methods

Forty one plant extracts and eight 7-methoxyflavones from Kaempferia parviflora Wall. ex Baker were screened for PDE5 and PDE6 inhibitory activities using the two-step radioactive assay. The PDE5 and PDE6 were prepared from mice lung and chicken retinas, respectively. All plant extracts were tested at 50 μg/ml whereas the pure compounds were tested at 10 μM.

Results

From forty one plant extracts tested, four showed the PDE5 inhibitory effect. The chemical constituents isolated from rhizomes of Kaempferia parviflora were further investigated on inhibitory activity against PDE5 and PDE6. The results showed that 7-methoxyflavones from this plant showed inhibition toward both enzymes. The most potent PDE5 inhibitor was 5,7-dimethoxyflavone (IC₅₀ = 10.64 ± 2.09 μM, selectivity on PDE5 over PDE6 = 3.71). Structure activity relationship showed that the methoxyl group at C-5 position of 7-methoxyflavones was necessary for PDE5 inhibition.

Conclusions

Kaempferia parviflora rhizome extract and its 7-methoxyflavone constituents had moderate inhibitory activity against PDE5. This finding provides an explanation for enhancing sexual performance in the traditional use of Kaempferia parviflora. Moreover, 5,7-dimethoxyflavones should make a useful lead compound to further develop clinically efficacious PDE5 inhibitors.     

Potential of medicinal plants from the Brazilian semi-arid region (Caatinga) against Staphylococcus epidermidis planktonic and biofilm lifestyles

Ethnopharmacological relevance

Medicinal plants from the Caatinga, a Brazilian xeric shrubland, are used in folk medicine to treat infections. These ethnopharmacological data can contribute to obtaining new antimicrobial/antibiofilm extracts and natural product prototypes for the development of new drugs. The aim of this study was to investigate the antibiofilm and antibacterial activities of 45 aqueous extracts from 24 Caatinga plant species.

Materials and methods

The effect of aqueous extracts on planktonic cells and on biofilm formation by Staphylococcus epidermidis was studied by the OD₆₀₀ absorbance and by the crystal violet assay, respectively. Scanning electron microscopy (SEM) was used to generate comparative images of extract-treated and untreated biofilms. Chromatographic analyses were performed to characterize the active extracts.

Results

The in vitro screening, at 0.4 mg/mL and 4.0 mg/mL, showed 20 plants effective in preventing biofilm formation and 13 plants able to inhibit planktonic bacterial growth. SEM images demonstrated distinct profiles of bacterial adhesion, matrix production and cell morphology according to different treatments and surfaces. The phytochemical analysis of the selected active extracts indicates the polyphenols, coumarins, steroids and terpenes as possible active compounds.

Conclusion

This study describes the first antibiofilm and antibacterial screening of Caatinga plants against S. epidermidis. The evaluation presented in this study confirms several ethnopharmacological reports and can be utilized to identify new antibiofilm and antibacterial products against S. epidermidis from traditional Brazilian medicine.     

Antimicrobial properties of stem bark extracts from Phyllanthus muellerianus (Kuntze) Excell

Ethnopharmacological relevance

The plants of the genus Phyllanthus (Euphorbiaceae) are widely distributed in most tropical and subtropical countries, and have long been used in folk medicine to treat several diseases. Particularly, Phyllanthus muellerianus (Kuntze) Excell, commonly called “mbolongo” in Cameroon, is used by pygmies baka as a remedy for tetanus and wound infections.

Aim of the study

To investigate the antimicrobial properties of Phyllanthus muellerianus (Kuntze) Excell (family Euphorbiaceae) stem bark used in Cameroon by baka pygmies as a remedy for wound healing and tetanus.

Materials and methods

Aqueous and methanol extracts with and without defatting treatment, were prepared and their activity against Clostridium sporogenes ATCC 3584, Staphylococcus aureus ATCC 6538, Streptococcus mutans ATCC 25175, Streptococcus pyogenes ATCC 19615, Escherichia coli ATCC 10536, Candida albicans ATCC 10231, was evaluated on the basis of the minimum inhibitory concentration (MIC) and the minimum bactericidal-fungicidal concentration (MBC-MFC) by the macrodilution method.

Results

Water extract showed a weak activity against Clostridium sporogenes (MIC 900 μg/mL) and resulted inactive at the tested concentrations against all the other microorganisms. The defatted methanol extract, inactive against Staphylococcus aureus, Escherichia coli, Candida albicans, exhibited a very interesting activity against Clostridium sporogenes and Streptococcus pyogenes (MIC 100 μg/mL and 300 μg/mL, respectively), which seems to validate the use of this plant in pygmies traditional medicine for the treatment of tetanus and wound infections. The activity found against Streptococcus mutans (300 μg/mL), aetiological agent of caries, may suggest a possible use of this plant as natural remedy to prevent dental diseases.

Conclusions

The activity against streptococci and Clostridium sporogenes ATCC 3584, showed by stem bark extracts of Phyllanthus muellerianus, traditionally used by baka pygmies to treat wound infections and tetanus, is reported for the first time.     

Assessment of the antimicrobial effect of three plants used for therapy of community-acquired urinary tract infection in Rio Grande do Sul (Brazil)

Ethnopharmacological relevance

The urinary tract infections (UTI) are among the infectious diseases of bacterial origin most commonly diagnosed, and may result in a significant mortality. The microorganisms most frequently involved in community-acquired infections are Escherichia coli and Klebsiella pneumoniae, both Gram-negative bacillus of the Enterobacteriaceae family. In southern Brazil, it is common the treatment of UTI using herbs and teas, a tradition inherited from the ancient indigenous people. Nevertheless, there is still poor scientific information about the action of these plants.

Materials and methods

Tests included the determination of minimum inhibitory concentration (MIC) by microdilution method at concentrations of 5000-156.25 μg/μL, and evaluation of antimicrobial activity by agar disc diffusion method at concentrations 500-12.5 μg/μL, against the microorganisms Escherichia coli and Klebsiella pneumoniae.

Results

In the tests for MIC and antimicrobial activity by disc diffusion method in agar, the growth of Escherichia coli and Klebsiella pneumoniae isolates were not inhibited by extracts from Piptochaetium montevidense, Bulbostylis capillaris and Juncus capillaceus employed in the study.

Conclusions

Despite the popular use of the plants used in this study, there is no relation between the use and the expected antimicrobial activity. Prolonged use of these plants may worsen the disease and lead to kidney involvement, and in severe cases, lead to death.     

Hypoglycemic activity of Thai medicinal plants selected from the Thai/Lanna Medicinal Recipe Database MANOSROI II

Ethnopharmacological relevance

Five medicinal plants including Anogeissus acuminata (Roxb. ex DC.) Gills. & Perr. (Combretaceae), Catunaregam tormentosa (Bl. ex DC.) Tirveng (Rubiaceae), Dioecrescis erythroclada (Kurz) Tirveng. (Rubiaceae), Mimosa pudica Linn. var. hispida Bren. (Fabaceae), and Rauwolfia serpentina (L). Benth. ex Kurz. (Apocyanaceae), which have been traditionally used for the treatment of diabetes mellitus and other diseases for several generations by the Thai-Lanna people in the Northern part of Thailand were investigated for their hypoglycemic activity in normoglycemic and alloxan, induced diabetic mice.

Materials and methods

The aqueous extracts of the selected five medicinal plants were tested for their phytochemicals, free radical scavenging activity and hypoglycemic activity on 18 h fasted normoglycemic and alloxan induced diabetic mice over a period of 4 h comparing with the standard anti-diabetic drugs (insulin and glibenclamide) using two way analysis of variance (ANOVA) as analytical tool. Phytochemical analysis was performed using the standard methods while 2,2-diphenyl-1-picrylhydrazine (DPPH) was used to test for free radical scavenging activities of the medicinal plant extracts.

Results

Phytochemicals detected in the extracts were glycosides, xanthones, tannins, alkaloids and saponins. Anogeissus acuminata showed the highest free radical scavenging activity with the IC₅₀ value of 11.00 μg/mL which was 4 folds of the standard ascorbic acid. Significant reduction in fasting blood glucose (FBG) levels of the normoglycemic mice was observed at 4 and 3 h with the extracts of Mimosa pudica (200 mg/kg bw) and Rauwolfia serpentina (100 mg/kg bw), and percentage decreases of 46.15 and 27.94% which were 0.76 and 1.47; 0.53 and 0.91 folds of insulin and glibenclamide, respectively. In alloxan induced diabetic mice, all extracts showed significant (p < 0.05) hypoglycemic activity, with the maximum FBG reduction of 78.96 at 100 mg/kg bw shown by Anogeissus acuminata at the 4 h. The hypoglycemic activity of Anogeissus acuminata was comparable to insulin (1.1 fold), but more potent than glibenclamide (1.76 folds).

Conclusions

Medicinal plants selected from the Thai/Lanna Medicinal Plant Recipe Database MANOSROI II showed hypoglycemic activity in normoglycemic and alloxan induced diabetic mice. This study confirmed the traditional use of these medicinal plants for the treatment of diabetes mellitus and the thiazolidiendiones mimic hypoglycemic effects of the medicinal plants was suggested.     

Antiplasmodial, anti-inflammatory and cytotoxic activities of various plant extracts from the Mascarene Archipelago

Aim of the study

Antiplasmodial activity, inhibition of nitric oxide (NO) overproduction, and anti-proliferative activity were investigated in vitro to evaluate the bioactive potential of the traditional pharmacopoeia of the Mascarene Archipelago, which is known for its biodiversity and for the richness of its endemic flora.

Materials and methods

A total of 45 methanol (MeOH) and dichloromethane (DCM) extracts were prepared from 19 plant species collected on Réunion and Mauritius Islands. Ninety-six-well microplate assays were performed on chloroquine sensitive Plasmodium falciparum 3D7 strain, on LPS-stimulated Raw 264.7 murine macrophages and on A-549, DLD-1 and WS1 human cells. Activity was evaluated through spectrophotometric methods.

Results

Activity was attributed to plant extracts expressing IC₅₀ < 50 μg/ml for antiplasmodial response, IC₅₀ < 100 μg/ml for cytotoxicity, and IC₅₀ < 130 μg/ml for anti-inflammatory reaction. The majority of the extracts tested (69%) exhibited potency in at least one of these three types of activity. This is the first report describing promising antiplasmodial activity (IC₅₀ < 15 μg/ml) for Psiadia dentata DCM extract and Terminalia bentzoe MeOH bark extract. NO inhibition assay revealed seven interesting plants, described for the first time as anti-inflammatory: Aphloia theiformis, Buddleja salviifolia, Eupatorium riparium, Hiptage benghalensis, Psiadia arguta, Psiadia dentata, and Scutia commersonii. Finally, anti-proliferative activity was observed for two endemic species, Geniostoma borbonicum and Nuxia verticillata.

Conclusion

Using the criterion of endemism as part of the criteria for traditional medicinal use raises the chances of finding original active principles. In our case, 86% of the endemic plants tested displayed pharmacological interest.     

Comparative ethnobotany and in-the-field antibacterial testing of medicinal plants used by the Bulu and inland Kaulong of Papua New Guinea

Ethnopharmacological relevance

The island of New Britain in Papua New Guinea is an area of great floristic and cultural diversity that has received little attention from ethnobotanists. Here we present the results of a comparative medicinal ethnobotanical survey of the Bulu and inland Kaulong; two distinct people groups inhabiting lowland rainforest on different sides of the island. A high proportion of species are used in the treatment of bacterial infections and plants with antibacterial activity were identified in the field using a specially developed antibacterial assay kit. Follow up testing with human pathogens was used to evaluate active plant material in more detail.

Materials and methods

Rapid appraisal techniques were used to survey both people groups with all data corroborated by three or more separate sources. Plants from both groups were tested in-the-field with a portable antibacterial test kit based on the agar diffusion assay, using a pressure cooker to sterilise glassware and media. Follow up laboratory based tests were carried out using standardised agar dilution protocols for drug resistant and drug sensitive strains of Staphylococcus aureus and Streptococcus pneumoniae.

Results

We find surprisingly little overlap in the plant species used by the two people groups with only 1 out of 70 species used for the same purpose. There is also a difference in emphasis in the conditions treated with 53% of Kaulong medicinal plants dedicated to treating tropical ulcers compared with only 8% of in the Bulu group. In-the-field testing identified Garcinia dulcis bark (a Kaulong tropical ulcer treatment) to have antibacterial activity and follow up tests against a drug resistant strain of Staphylococcus aureus (a pathogen implicated in tropical ulcer pathogenesis) revealed the crude bark extract to be potently active with an MIC of just 1 mg/ml.

Conclusions

The results demonstrate extreme differences in medicinal plant use between two people groups living a mere 100 km apart and suggests the two medicinal plant systems have developed in isolation from one another. In-the-field antibacterial testing of plant extracts was found to be a valuable technique that enabled early identification of active plant material.     

Consequences of subchronic exposure to ethanolic extract from fruits and leaves of Schinus molle var. areira L. in mice

Aim of the study

Several extracts of Schinus molle var. areira L. plant proved to be useful for the treatment of different pathologies and for the control of insect pest. Due to these potential uses, it is necessary to study their safety. In this work, we evaluated the effects of subchronic exposure to ethanolic extracts from leaves and fruits of Schinus molle var. areira in mice.

Materials and methods

The plant extract was added to the diet at 1 g/kg body weight/day for 90 days. At the end of the exposure, behavioral and functional parameters in a functional observational battery and motor activity in an open field were assessed. Finally, several biochemical and histopathological studies were realized.

Results

The exposure to extract from leaves produced an increase in the number of rearings in the open field and of urine pools in the functional observational battery. On the other hand, the exposure to extract from fruits produced an increase in the neutrophil count and a decrease in the lymphocyte count and in the total cholesterol levels. None of the exposures affected the different organs evaluated.

Conclusions

Our results suggest that subchronic exposure to ethanolic extracts from leaves and fruits of Schinus molle var. areira should be potentially useful in the treatment of lipid pathologies and safe to use.     

In vitro antitrypanosomal and antileishmanial activity of plants used in Benin in traditional medicine and bio-guided fractionation of the most active extract

Ethnopharmacological relevance

The aim of the study was to evaluate the in vitro antitrypanosomal and antileishmanial activity of crude extracts of 10 plant species traditionally used in Benin to treat parasitic infections.

Materials and methods

For each species, dichloromethane, methanol and aqueous extracts were tested. Their antitrypanosomal and antileishmanial activities were evaluated in vitro on Trypanosoma brucei brucei (strain 427) (Tbb) and on promastigotes of Leishmania mexicana mexicana (MHOM/BZ/84/BEL46) (Lmm).

Results

The best growth inhibition was observed with the dichloromethane extracts of aerial parts of Acanthospermum hispidum DC. (Asteraceae) (IC₅₀ = 14.5 μg/ml on Tbb and 11.1 μg/ml on Lmm), twigs of Keetia leucantha (K. Krause) Bridson (syn. Plectronia leucantha Krause) (IC₅₀ = 5.8 μg/ml on Tbb), aerial parts of Byrsocarpus coccineus Schumach. & Thonn (syn. Rourea coccinea (Schumach. & Thonn.) Hook.f.) (IC₅₀ = 14.7 μg/ml on Tbb) and aerial parts of Carpolobia lutea G.Don. (IC₅₀ = 18.3 μg/ml on Tbb). All these extracts had a low cytotoxicity. It is not the case for the methanolic and water extracts of roots of Anchomanes difformis (Blume) Engl. (IC₅₀ = 14.7 and 13.8 μg/ml on Tbb) which were toxic at the same concentration range on WI38, human cells. A bio-guided fractionation of the most active extract of Keetia leucantha allowed to identify oleanolic acid and ursolic acid as responsible for the observed activities.

Conclusion

Our study gives some justification for antiparasitic activity of some investigated plants.     

Mexican medicinal plants used for cancer treatment: pharmacological, phytochemical and ethnobotanical studies

Aim of the study

This review provides a summary of Mexican medicinal flora in terms of ethnobotanical, pharmacology, and chemistry of natural products related to anticancer activity.

Materials and methods

Bibliographic investigation was carried out by analyzing recognized books and peer-reviewed papers, consulting worldwide accepted scientific databases from the last five decades. Mexican plants with attributed anti-cancer properties were classified into six groups: (a) plant extracts that have been evaluated for cytotoxic effects, (b) plant extracts that have documented anti-tumoral effects, (c) plants with active compounds tested on cancer cell lines, (d) plants with novel active compounds found only in Mexican species, (e) plants with active compounds that have been assayed on animal models and (f) plants with anti-cancer ethnopharmacological references but without scientific studies.

Results

Three hundred plant species belonging to 90 botanical families used for cancer treatment have been recorded, of which only 181 have been experimentally analyzed. The remaining 119 plant species are in use in empirical treatment of diseases consistent with cancer symptomatology. Only 88 of the plant extracts experimentally studied in in vitro cellular models have demonstrated active cytotoxic effects in at least one cancer cell line, and 14 out of the 88 have also been tested in vivo with the results that one of them demonstrated anti-neoplasic effects. A total of 187 compounds, belonging to 19 types of plant secondary metabolites, have been isolated from 51 plant extracts with active cytotoxic effects, but only 77 of these compounds (41%) have demonstrated cytoxicity. Seventeen of these active principles have not been reported in other plant species. However, only 5 compounds have been evaluated in vivo, and 3 of them could be considered as active.

Conclusion

Clearly, this review indicates that it is time to increase the number of experimental studies and to begin to conduct clinical trials with those Mexican plants and its active compounds selected by in vitro and in vivo activities. Also, the mechanisms of action by which plant extracts and their active compounds exert anti-cancer effects remain to be studied.     

In vitro antimicrobial synergism within plant extract combinations from three South African medicinal bulbs

Ethnopharmacological relevance

Tulbaghia violacea, Hypoxis hemerocallidea and Merwilla plumbea are used in South African traditional medicine for the treatment of some infectious diseases and other ailments.

Aim of the study

The study aimed at investigating the antimicrobial efficacies of independent and various within-plant extract combinations of three medicinal bulbs to understand the possible pharmacological interactions.

Materials and methods

Bulb and leaf extracts of the three medicinal plants, independently and in combinations, were comparatively assessed for antimicrobial activity against two Gram-positive and two Gram-negative bacteria and Candida albicans using the microdilution method. The fractional inhibitory concentration indices (FIC) for two extract combinations were determined.

Results

At least one extract combination in each plant sample demonstrated good antimicrobial activity against all the test organisms. The efficacies of the various extract combinations in each plant sample varied, with the strongest synergistic effect exhibited by the proportional extract yield combination of PE and DCM extracts in Merwilla plumbea bulb sample against Staphylococcus aureus (FIC index of 0.1). Most extract combinations demonstrated either a synergistic, additive or indifferent interaction effect against the test bacteria with only a few exhibiting antagonistic effects.

Conclusion

The observed antimicrobial efficacy and synergistic interactions indicate the beneficial aspects of combination chemotherapy of medicinal plant extracts in the treatment of infectious diseases.