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.     

Xanthine oxidase inhibitory properties of Czech medicinal plants

Aim of the study

To investigate in vitro xanthine oxidase inhibitory properties of plants traditionally used in Czech Republic and Central-East Europe region for gout, arthritis or rheumatism treatment.

Materials and methods

Methylene chloride-methanolic and two ethanolic extracts of 27 plant species were screened for in vitro xanthine oxidase inhibitory activity using a spectrophotometric method.

Results

Around 50% of the species exhibited some degree of xanthine oxidase inhibitory properties at 200 μg/mL, showing a moderate correlation (r = 0.59) with total phenol content. The most active were methylene chloride-methanolic extracts of Populus nigra and Betula pendula, with IC₅₀ of 8.3 and 25.9 μg/mL, respectively, followed by 80% ethanolic extract of Caryophyllus aromaticus and Hypericum perforatum, both under 50 μg/mL.

Conclusions

Populus nigra and Betula pendula were identified as species with the highest xanthine oxidase inhibitory potential in our study. This correlates with the ethnobotanical data on their use in Central European folklore and provides the basis for further investigation on these plants.     

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.     

Mutagenicity, antimutagenicity and cytotoxicity evaluation of South African Podocarpus species

Ethnopharmacological relevance

Four species of Podocarpus are used in traditional medicine both in human and animal healthcare in South Africa. In vitro pharmacological screening of leaf and stem extracts of these species exhibited potent antimicrobial, anti-inflammatory, anti-tyrosinase, anthelmintic, acetylcholinesterase inhibitory and antioxidant activities.

Aim of the study

To investigate the mutagenicity, antimutagenicity and cytotoxicity effects of leaf and stem extract of South African Podocarpus species.

Material and methods

The mutagenicity and cytotoxic effects of extracts from four species of Podocarpus were tested using the Salmonella/microsome assay with and without metabolic activation, based on the plate-incorporation method and neutral red uptake (NRU) assay respectively. Five Salmonella typhimurium tester strains; TA98, TA100, TA102, TA1535 and TA1537 were used for mutagenicity testing. The relative cytotoxicity of the extracts was assessed by determining their NI₅₀ values (50% inhibition of NRU).

Results

The extracts did not show any mutagenic effects against all the tester strains with or without metabolic activation. All extracts demonstrated a strong antimutagenic effect on the mutations induced by 4NQO, decreasing its mutagenic effect in a dose-dependent manner. Strong cytotoxic effects were exhibited by petroleum ether extracts as compared to 80% ethanol extracts. When HepG2 cells were in contact with plant extracts in an increasing concentration, slopes of NRU decreased (highest-lowest %) following a concentration-dependent pattern. For 80% ethanol extracts, the most toxic extract in terms of percentage viability was leaves of Podocarpus falcatus whereby at 0.2 mg/ml, the viability of the cells was 38.9%. Stem extract of Podocarpus latifolius was the most toxic among PE extracts, giving a percentage viability of 46.4 at 0.1 mg/ml.

Conclusion

Absence of mutagenicity does not indicate lack of toxicity, as was observed from these extracts. These findings will help in assessing the safety measures to be considered in the use of these species and also the need to determine the cytotoxic potential of these species against various forms of human cancer cells.     

Comparative study of antioxidant and anti-inflammatory activities and genotoxicity of alcoholic and aqueous extracts of four Fabiana species that grow in mountainous area of Argentina

Ethnopharmacological relevance

Fabiana species (Solanaceae family) extracts have long been used in Argentinean traditional medicine as anti-inflammatories, antiseptic, bone fractures and others diseases, but there is no scientific evidence which supports their use.

Aim of the study

The present study was conducted to evaluate the ability of aqueous and ethanolic extracts of four Fabiana species (Fabiana bryoides Phil., Fabiana punensis A.C. Arroyo, Fabiana densa J. Rèmy and Fabiana patagonica Speg.) to inhibit key enzymes in inflammatory processes, free radical scavenging properties and genotoxic effects.

Materials and methods

HPLC-DAD of aqueous and ethanolic extracts from four Fabiana species was established. All Fabiana extracts were evaluated on their ability to inhibit hyaluronidase and lipoxygenase enzymes to assess their activity against inflammatory mediators. Antioxidant capacity was determined using the 2,2′-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assays and β-carotene-linolenic acid assay. Genotoxicity was evaluated by the Ames assay.

Results

The results indicated that the chromatographic patterns of four Fabiana species were different in quantity and absorption intensity of peaks. The alcoholic extract of Fabiana punensis was the most active scavenger of DPPH and ABTS⁺ radicals (SC₅₀ values of 3.85 ± 0.24 and 2.56 ± 0.10 μg GAE/mL, respectively). Fabiana patagonica extracts exhibited the highest peroxyl radical scavenging activity compared with the other three taxa (IC₅₀ values between 1.00 ± 0.04 and 4.46 ± 0.40 μg GAE/mL for all extracts) and anti-lipoxygenase activity with IC₅₀ values between 12.5 and 15.5 μg GAE/mL. The absence of mutagenicity indicates that the DNA does not seem to be a relevant target for these extracts. Fabiana bryoides ethanolic extract showed an interesting effect: it inhibited spontaneous mutagenesis, which could be considered as an antimutagenic effect in the TA98 (+S9) and TA100 (+S9/−S9) strains. The potency differences found between the species could be consequence of the different phytochemical pattern observed by HPLC.

Conclusions

The inhibitory effects on lipoxygenase and hyaluronidase, free radical scavenging activities and lack of genotoxicity of Fabiana extracts may support the folk use of Fabiana punensis, Fabiana patagonica, Fabiana bryoides and Fabiana densa as inhibitor of inflammatory mediators.     

In vitro antimicrobial, anthelmintic and cyclooxygenase-inhibitory activities and phytochemical analysis of Leucosidea sericea

Ethnopharmacological relevance

Leucosidea sericea is used as a vermifuge and in the treatment of ophthalmia by various tribes in southern African countries.

Aim of the study

The study aimed at screening leaves and stems of Leucosidea sericea for pharmacological activity and validating the plant's traditional use. A general phytochemical screening was also carried out.

Materials and methods

Petroleum ether (PE), dichloromethane (DCM), ethanol (EtOH) and water extracts of the plant parts were investigated for antimicrobial, anthelmintic and cyclooxygenase (COX) inhibitory activities. Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae) and Candida albicans were used for the antimicrobial evaluation. Caenorhabditis elegans was used for the anthelmintic assay using the microdilution technique. Cyclooxygenase-1 and -2 (COX-1 and -2) were used to evaluate the anti-inflammatory potential of the plant extracts. Phytochemical analysis for phenolic compounds, including gallotannins, condensed tannins and flavonoids was done using 50% methanol extracts of the leaves and stems employing spectrophotometric methods.

Results

The leaf extracts exhibited broad spectrum antibacterial activity ranging from 0.025 to 6.25 mg/ml. The most noteworthy minimum inhibitory concentration (MIC) of 0.025 mg/ml was exhibited by PE and DCM leaf extracts against Bacillus subtilis and Staphylococcus aureus, respectively. In the anthelmintic assay, the best minimum lethal concentration (MLC) value of 0.26 mg/ml was observed for the DCM and EtOH leaf extracts. Both leaf and stem organic solvent extracts exhibited high to moderate inhibition against COX-1 and -2 at a screening concentration of 250 μg/ml. At lower concentrations, the extracts displayed a dose-dependent inhibition, with the lowest IC₅₀ values of 0.06 μg/ml (COX-1) and 12.66 μg/ml (COX-2) exhibited by the PE extract of the leaves. Generally, the leaf extracts exhibited better pharmacological activities and contained higher amounts of phenolic compounds than the stem extracts. Alkaloids and saponins were only detected in the leaf and stem extracts, respectively.

Conclusion

The reported results support the local use of Leucosidea sericea against eye infections and as a vermifuge. The pharmacological activities exhibited by the leaf extracts are probably due to their higher phenolic levels.     

Evaluation of the anti-inflammatory properties of Dodonaea polyandra, a Kaanju traditional medicine

Ethnopharmacological relevance

Extracts of the medicinal plant species Dodonaea polyandra were investigated as part of a collegial research partnership between Northern Kaanju traditional owners represented by Chuulangun Aboriginal Corporation (centred on the Wenlock and Pascoe Rivers, Cape York Peninsula, Queensland, Australia) and university-based researchers. D. polyandra, known as “Uncha” in Kaanju language, is used in Northern Kaanju Traditional Medicine for relief from pain associated with toothache and related ailments. The species has a restricted distribution in Cape York Peninsula and there has been no previous Western scientific investigation of its pharmacology or chemistry.

Aim of the study

The current study investigates the anti-inflammatory effects of several extracts from D. polyandra.

Materials and methods

Phytochemical screening was conducted using TLC. Anti-inflammatory effects of leaf extracts were determined using an acute mouse ear oedema model induced by croton oil and 12-o-tetradecanoylphorbol-13-acetate (TPA) chemical irritants.

Results

Flavonoid and terpenoid secondary compounds were detected in leaf extracts of D. polyandra. Non-polar hexane and methylene chloride/methanol extracts showed potent inhibition of inflammation in TPA-induced mouse ear oedema by 72.12 and 79.81%, respectively, after 24 h at 0.4 mg/ear.

Conclusion

In a mouse model of acute inflammation, this study revealed that leaf extracts of D. polyandra possess significant anti-inflammatory potential. These results contribute to a Western scientific understanding of the ethnopharmacological use of the plant in Northern Kaanju Medicine for reducing tooth-related pain.     

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.     

Investigation of plant extracts in traditional medicine of the Brazilian Cerrado against protozoans and yeasts

Aim of the study

To investigate the activities of the 217 plant extracts in traditional medicine of the Brazilian Cerrado against protozoans and yeasts.

Materials and methods

Plant extracts were prepared by the method of maceration using solvents of different polarities. The growth inhibition of chloroquine-resistant Plasmodium falciparum strain (FcB1) was determined by measuring the radioactivity of the tritiated hypoxanthine incorporated. Activity against Leishmania (Leishmania) chagasi and Trypanosoma cruzi was measured by the MTT colorimetric assay. The antifungal tests were carried out by using the CLSI method. The active extracts were tested also by cytotoxicity assay using NIH-3T3 cells of mammalian fibroblasts.

Results

Two hundred and seventeen extracts of plants were tested against Plasmodium falciparum. The eleven active extracts, belonging to eight plant species were evaluated against L. (L.) chagasi, Trypanosoma cruzi, yeasts and in NIH-3T3 cells. The results found in these biological models are consistent with the ethnopharmacological data of these plants. The ethyl acetate extract of Diospyros hispida root showed IC₅₀ values of 1 μg/mL against Plasmodium falciparum. This extract demonstrated no toxicity against mammalian cells, resulting in a significant selectivity index (SI) of 435.8. The dichloromethane extract of Calophyllum brasiliense root wood was active against Cryptococcus gattii LMGO 01 with MIC of 1.95 μg/mL; and Candida albicans ATCC 10231 and Candida krusei LMGO 174, both with MIC of 7.81 μg/mL. The same extract was also active against Plasmodium falciparum and L. (L.) chagasi with IC₅₀ of 6.7 and 27.6 μg/mL respectively. The ethyl acetate extract of Spiranthera odoratissima leaves was active against Cryptococcus gattii LMGO 01 with MIC of 31.25 μg/mL, and against Plasmodium falciparum with IC₅₀ of 9.2 μg/mL and Trypanosoma cruzi with IC₅₀ of 56.3 μg/mL.

Conclusion

The active extracts for protozoans and human pathogenic yeasts are considered promising to continue the search for the identification and development of leading compounds.     

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,antioxidant, mutagenic and antimutagenic activities of Distephanus angulifolius and Ormocarpum trichocarpum

Ethnopharmacological relevance

The leaves of Distephanus angulifolius and Ormocarpum trichocarpum are used for treating stomach-related ailments in traditional medicine.

Aims of the study

The present study evaluated the antibacterial, antioxidant, mutagenic and antimutagenic properties of extracts obtained from the leaves of Distephanus angulifolius and Ormocarpum trichocarpum.

Materials and methods

The microtitre bioassay was used to determine the antibacterial activity against three Gram-positive and three Gram-negative bacteria. Antioxidant activity was determined using the free-radical scavenging and β-carotene-linoleic acid model assays. The safety and possible protective properties of the extracts were investigated using Ames test.

Results

Dichloromethane fractions of both plants displayed a broad-spectrum antibacterial activity with minimum inhibitory concentrations ranging from 0.16 to 0.63 mg/ml. A dose-dependent antioxidant activity was recorded in both plant species. All the evaluated samples showed no mutagenic as well as weak or no antimutagenic properties in the absence of exogenous metabolic activation.

Conclusion

The results demonstrated the antibacterial and antioxidant activities of the leaves obtained from the two plant species. Furthermore, the data provides a rationale for the use of the plant species in treating stomach-related ailments in traditional medicine.     

Antibacterial activity of the roots,stems and leaves of Alchornea floribunda

Ethnopharmacological relevance

Alchornea floribunda Müll. Arg. is used in traditional medicine across Africa for the treatment of bacterial, fungal, parasitic and inflammatory disorders.

Aim of the study

To evaluate the antibacterial activity of the crude extracts of different plant parts in order to provide a scientific rationale for the proposed broad efficacy of Alchornea floribunda in the treatment of bacterial infections.

Materials and methods

Extracts of roots, stems and leaves were prepared using solvents of various polarities in order to extract a wide range of phytochemicals. The antibacterial activity of these crude extracts was evaluated by micro-dilution assay, against Gram-positive (i.e. Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus and Staphylococcus saprophyticus) as well as Gram-negative (i.e. Escherichia coli, Klebsiella pneumoniae, Moraxella catarrhalis and Proteus mirabilis) bacteria.

Results

Generally, the ethanol (EtOH), methanol (MeOH), ethyl acetate (EtOAc) and chloroform (CHCl₃) extracts demonstrated the best activities, with the leaves exhibiting the highest average activity for six of the eight pathogens. Of these, the ethanolic leaf extract was the most active against Staphylococcus aureus with an MIC value of 50 µg/mL. Some other notable activity was observed for the ethyl acetate and chloroform root extracts against Staphylococcus aureus (50 µg/mL), and for selected stem extracts against Staphylococcus aureus (50 µg/mL), Klebsiella pneumoniae (63 µg/mL) and Staphylococcus saprophyticus (63 µg/mL).

Conclusion

This study demonstrates the promising antibacterial activity of Alchornea floribunda against both Gram-positive and Gram-negative bacteria responsible for gastrointestinal, skin, respiratory and urinary ailments, and validates its use in the ethnopharmacology of the region.     

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.     

Antituberculosis potential of some ethnobotanically selected Malaysian plants

Aim of the study

Many local plants are used in Malaysian traditional medicine to treat respiratory diseases including symptoms of tuberculosis. The aim of the study was to screen 78 plant extracts from 70 Malaysian plant species used in traditional medicine to treat respiratory diseases including symptoms of tuberculosis for activity against Mycobacterium tuberculosis H37Rv using a colorimetric microplate-based assay.

Materials and methods

Plant extracts were prepared by maceration in methanol (80%) and antituberculosis screening was carried out using Tetrazolium bromide microplate assay (TEMA) method to determine the minimum inhibitory concentration (MIC).

Results

Thirty-eight plant extracts from 36 plant species exhibited antituberculosis activity with MICs in the range of 1600-400 μg/ml. The leaf extract of Angiopteris evecta exhibited the highest activity with MIC of 400 μg/ml. Five other extracts, namely, Costus speciosus (stem and flower), Piper sarmentosum (whole plant), Pluchea indica (leaf), Pluchea indica (flower), and Tabernaemontana coronaria (leaf) exhibited antituberculosis activity, each with MIC of 800 μg/ml. To the best of our knowledge, this is the first report of in vitro high throughput screening of Malaysian medicinal plants for antituberculosis activity.

Conclusions

Antituberculosis activity of extracts of some plants justifies, to a certain extent their ethnomedicinal uses as remedies for symptoms of tuberculosis. These results also support the general view that, selecting the plants based on ethnobotanical criteria would enhance the probability of finding species with antituberculosis activity.     

Anti-inflammatory activity of Eupatorium perfoliatum L. extracts, eupafolin, and dimeric guaianolide via iNOS inhibitory activity and modulation of inflammation-related cytokines and chemokines

Ethnopharmacological relevance

Eupatorium perfoliatum L. has been used traditionally for the treatment of fever, malaria and inflammation-associated diseases. Nowadays it is mostly used as immune activating remedy. The following study was performed to evaluate extracts with different polarity and defined lead-compounds from the herbal material on potential in vitro activities concerning immune cell activation, phagocytosis, and inflammation-related processes.

Materials and methods

MeOH-, EtOH-, and DCM extracts, beside several subfractions and isolated polysaccharides, sesquiterpene lactones and flavonoids were prepared and characterized analytically from the aerial parts of E. perfoliatum. Immunological activity was tested within lymphocyte transformation test on PBMC, test on enhancement of phagocytosis and of NO-production by murine RAW 264.7 macrophages. Anti-inflammatory effects were assessed from LPS-stimulated RAW 264.7 cells by NO/iNOS quantification, gene array, real-time PCR and ELISA.

Results

No stimulatory activity was found within lymphocyte transformation test, for phagocytic activity and NO formation in macrophages. MeOH-, EtOH- and DCM extracts showed anti-inflammatory activity against LPS-stimulated macrophages by inhibition of NO release (IC₅₀ > 100, 89, 19 μg/mL resp.) with eupafolin and a dimeric guaianolide having prominent NO inhibiting activity (IC₅₀ 6 resp. 16 μM). Anti-inflammatory activity was found on gene and protein level by significant down-regulation of cytokines CSF-3, IL-1α, IL-1β, and chemokines CCL2, CCL22 and CXCL10. Also TNF was down-regulated moderately (−17%).

Conclusions

Although the postulated immunostimulating properties of E. perfoliatum have not been confirmed, the anti-inflammatory effects can be seen as a verification of the traditional use against inflammatory diseases.     

Anti-inflammatory,anticholinesterase, antioxidant and phytochemical properties of medicinal plants used for pain-related ailments in South Africa

Ethnopharmacological relevance

Extracts of seven South African medicinal plants used traditionally for the treatment of pain-related ailments were evaluated.

Aims of the study

The study was aimed at evaluating medicinal and therapeutic potentials of the investigated traditional medicinal plants. Plant extracts were evaluated for anti-inflammatory activity and other pharmacological properties such as anticholinesterase and antioxidant activities. Phytochemical analysis of total phenolic contents, condensed tannins, gallotannins and flavonoids in the aqueous methanol extracts of the medicinal plants were also carried out.

Materials and methods

The evaluation of anti-inflammatory activity of 50% methanol (50% MeOH), petroleum ether (PE), dichloromethane (DCM) and ethanol (EtOH) plant extracts was done against cyclooxygenase-1 and -2 (COX-1 and COX-2) enzymes. 50% MeOH, PE, DCM and EtOH extracts were tested for acetylcholinesterase (AChE) inhibition, while 50% MeOH extracts were tested for 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity and ferric-reducing power in the antioxidant assays. Total phenolic compounds, condensed tannins, gallotannins and flavonoids were quantitatively determined using spectrophotometric methods.

Results

At the screening assay concentration (0.25 μg/μl), 13 extracts showed good COX-1 inhibitory activity (>50%), while good activity was observed in 15 extracts against COX-2 enzyme. All the extracts of Crinum moorei (bulbs) showed good inhibition against both COX-1 and COX-2 enzymes. Though not significantly different (P = 0.05), the highest COX-1 percentage inhibition (100%) was shown by Aloe ferox leaf PE and Colocasia antiquorum tuber DCM extracts, while Colocasia antiquorum tuber PE extract exhibited the highest (92.7%) percentage inhibition against COX-2. Crinum moorei bulb DCM extract showed the lowest EC₅₀ value (2.9 μg/ml) in the AChE assay. In addition, good to moderate bioactivities were observed in some extracts of Aloe ferox (leaves), Crinum moorei (bulbs) and Pycnostachys reticulata (leaves) in all the assays. The presence and/or amounts of phenolic compounds varied with plant species.

Conclusion

The results obtained in this study validate the use of the investigated medicinal plants in South African traditional medicine for pain-related ailments.     

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.     

Genotoxic and clastogenic activity of saponins extracted from Nauclea bark as assessed by the micronucleus and the comet assays in Chinese Hamster Ovary cells

Ethnopharmacological relevance

Bark extracts of Nauclea latifolia, Nauclea diderrichii, Nauclea pobeguinii and Nauclea vandergutchii are used in traditional medicine in West and South Africa for the treatment of fevers, diarrhea and malaria.

Aim of the study

To estimate the possible long-term toxicity and genotoxicity of plant extracts (dichloromethane, methanol, water/methanol, water) and saponins.

Materials and methods

The clastogenicity of plant extracts and saponins was assessed by the micronucleus assay performed on Chinese Hamster Ovary cells. The DNA-damaging activity of saponin mixture was assessed by the comet assay on Chinese Hamster ovary cells.

Results

Hydromethanolic extracts from Nauclea latifolia, Nauclea diderrichii and Nauclea pobeguinii exhibited a significant clastogenic/aneugenic activity without S9 mix. The hydromethanolic extract from Nauclea diderrichii was the most clastogenic/aneugenic fraction with a Minimal Active Concentration (MAC) of 23.1 μg mL⁻¹. It was submitted to a separation step leading to six main saponins identified as quinovic acid glycosides (saponins A, D, E, G, J, K). None of the isolated saponins exerted a significant clastogenic/aneugenic activity by the micronucleus assay, however a mixture made with equal quantities of each of the six saponins exhibited a direct genotoxic/clastogenic activity as assessed by both the micronucleus assay and the comet assay on Chinese Hamster Ovary cells.

Conclusion

Saponins present in the hydromethanolic extracts of Nauclea induced synergistic in vitro DNA-damage and chromosome mutations in mammalian cells. This genotoxic activity was probably due to the capacity of Nauclea saponins to reduce cell defense against oxidative stress through the inhibition of glutathione-S-transferase activity.     

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.