Prostaglandin Synthesis Inhibitory Activity in Zulu,Xhosa and Sotho Medicinal Plants

Twenty-six plants used by Zulu healers for the treatment of pain and inflammation were assayed for cyclooxygenase inhibitory activity. The plant parts used by the traditional healers were dried and milled. Ethanol and aqueous extracts of the plants were prepared and assayed. Several plant extracts exhibited high inhibitory activity in the assay. Among these were Acacia rehmanniana, Cryptocarya latifolia, Dichrostachys cinerea, Erythrophleum lasianthum, Euclea natalensis, Felicia muricata, Mohria caffrorum, Phygelius capensis, Siphonochilus aethiopicus, Trichilia emetica and Turraea floribunda . The ethanol extracts generally showed higher activity than the aqueous extracts. © 1997 by John Wiley & Sons, Ltd.     

Screening of Yemeni medicinal plants for antibacterial and cytotoxic activities

Ethanolic extracts of 20 selected plant species used by Yemeni traditional healers to treat infectious diseases were screened for their antibacterial activity against both Gram-positive and Gram-negative bacteria, as well as for cytotoxic activity. Fourteen of the ethanolic extracts showed variable degrees of antibacterial activity. The active ethanolic extracts were partitioned between ethyl acetate and water for a first separation. The ethyl acetate extract of Lawsonia inermis was found to be the most active one against all bacteria in the test system. Other promising results could be obtained from extracts of Aloe perryi, Indigofera oblongifolia, Meriandra benghalensis and Ziziphus spina christi. Additionally, the ethanolic extracts of the 20 plants under investigation were tested for their cytotoxic effects on FL-cells using the neutral red assay. Extracts of Calotropis procera, Chenopodium murale, Pulicaria orientalis, Tribulus terrestris and Withania somniferum displayed a remarkable activity.     

Screening of Zulu medicinal plants for prostaglandin-synthesis inhibitors

Aqueous and ethanolic extracts of 39 plants used in traditional Zulu medicine to treat headache or inflammatory diseases were screened for prostaglandin-synthesis inhibitors. Extracts were tested in an in vitro assay for cyclooxygenase inhibitors. In general, ethanolic extracts caused higher inhibition than aqueous extracts. Two-thirds of the plants screened had high inhibitory activity. The highest inhibition was obtained with ethanolic extracts of Bidens pilosa, Eucomis autumnalis, Harpephyllum caffrum, Helichrysum nudifolium, Leonotis intermedia, L. leonorus, Ocotea bullata, Rumex saggitatus, Solanum mauritianum, Synadenium cupulare and Trichilia dregeana.     

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.     

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.     

Anti-inflammatory and phytochemical properties of twelve medicinal plants used for treating gastro-intestinal ailments in South Africa

Ethnopharmacological relevance

The investigated medicinal plants are commonly used for the treatment of pains and cramps related to gastro-intestinal tract infections in South African traditional medicine.

Aims of the study

This study aimed to evaluate the ability of the plant extracts to inhibit cyclooxygenase enzymes. Phytochemical analysis was also carried out in the quest to determine some plant metabolites that may be responsible for the observed anti-inflammatory activity.

Materials and methods

The cyclooxygenase assay was used to test for the anti-inflammatory activity of the plant extracts using cyclooxygenase-1 and -2 (COX-1 and COX-2) enzymes. Total phenolic compounds including condensed tannins, gallotannins and flavonoids were quantitatively determined using spectrophotometric methods. Qualitative tests for alkaloids and saponins were also carried out.

Results

Most of the plant extracts evaluated showed dose dependent activity against COX-1 and/or COX-2 enzymes. Agapanthus campanulatus root dichloromethane extract showed the highest COX-2 inhibitory activity (83.7%) at 62.5 μg/ml. The presence and/or amounts of phenolics, condensed tannins, gallotannins, flavonoids, alkaloids and saponins varied with plant parts and species.

Conclusion

The results support the use of the investigated plant in treating pain and cramp related to gastro-intestinal tract infections. To some extent, the observed anti-inflammatory activity could be attributed to the various plant secondary metabolites detected in the plant materials.     

Effects of the extracts of Desmodium adscendens on anaphylaxis

Desmodium adscendens, used by herbalists in Ghana for the treatment of asthma, is anti-anaphylactic in vitro. As the plant material is administered orally, in vivo studies of its anti-anaphylactic property were undertaken using the guinea-pig.The results show that both aqueous and ethanolic extracts of D. adscendens, when taken orally, reduce anaphylactic contractions, interfere with histamine-induced contractions, and reduce the amount of smooth muscle stimulating substances released from lung tissue of guinea pigs.     

Screening of indigenous plants from South Africa for affinity to the serotonin reuptake transport protein

Seventy five extracts from 34 indigenous plant species used in South African traditional medicine or taxonomically related to these were investigated for their affinity to the serotonin reuptake transport protein, making use of an in vitro serotonin reuptake transport protein binding assay. Aqueous and 70% ethanolic extracts of various plant parts were screened and 45 extracts derived from 15 plant species showed affinity. The affinity of 12 extracts from four plants was characterized as high (more than 50% inhibition at 5, 1, and 0.5 mg/ml). Plant species with high affinity to the serotonin reuptake transport protein included Agapanthus campanulatus, Boophane disticha, Datura ferox and Xysmalobium undulatum. Agapanthus campanulatus yielded high activity in aqueous extracts from leaves and flowers. Boophane disticha showed high activity both in aqueous and ethanolic extracts of leaves and bulbs. Datura ferox showed high activity in aqueous extracts from the seeds and Xysmalobium undulatum showed high activity in the ethanolic extract of the whole plant.     

In vitro antiplasmodial activity of stem and root extracts of Nauclea latifolia S.M. (Rubiaceae)

Aqueous extracts from Nauclea latifolia S.M. (Rubiaceae), a plant commonly used in Ivory Coast by traditional healers for the treatment of malaria, were tested on two strains of Plasmodium falciparum: FcB1-Colombia (chloroquine-resistant) and a Nigerian strain (chloroquine-sensitive). The extracts were obtained from stems and roots of the plant in two forms, infusion and decoction, both methods used by most traditional healers. The in vitro activity of N. latifolia extracts on P. falciparum was assessed both visually and by a radioactive method. The visual analysis allowed determination of the time of extract action on the erythrocytic cycle, as well as the parasitic stage of most inhibitory effect. Similar results were obtained applying fresh, frozen or lyophilized extracts. The IC₅₀ values determined were within the range already reported for other antimalarial plants such as Azadirachta indica A. Juss (Meliaceae) or Artemisia annua L. (Asteraceae). Aqueous extracts of N. latifolia inhibited P. falciparum (FcB1 strain) mainly at the end of the erythrocytic cycle (32nd to 48th hour).     

Pharmacological effects of Agapanthus africanus on the isolated rat uterus.

The Agapanthus africanus plant is used by South African traditional healers as a phytomedicine in herbal remedies to treat pregnancy-related ailments and to augment labour. It has already been shown that an aqueous extract of A. africanus causes smooth muscle contractions in the isolated uterus and ileum preparations. In the present study, the effects of an aqueous extract of A. africanus leaves was examined on receptor systems involved in contraction of the uterine smooth muscle in order to determine the mechanism of its pharmacological effect relevant to its ethnic use to augment labour. The extract was tested on the isolated rat uterus preparation. The aqueous extract of A. africanus leaves was found to exhibit agonist activity on uterine muscarinic receptors and to promote the synthesis of prostaglandins in the oestrogenized rat uterus. Some pharmacological justification for the ethnic use of A. africanus as a herbal oxytocic in prolonged labour has been provided.     

Antibacterial effect of plant extracts against Helicobacter pylori

The aim of this work was to evaluate the antibacterial effect of plant extracts as alternative and[sol ]or as active agents supporting antibiotics for treating Helicobacter pylori infection. The effect of either, ethanolic or aqueous extracts from 17 plant materials were studied against one H. pylori standard strain and 11 clinical isolates using a disc diffusion test and by evaluating the minimum inhibitory concentration (MIC) on solid media. An inhibitory activity against H. pylori strains was recorded in a large percentage of tested plants. MIC values of ethanolic extracts were from two to four concentration steps lower than the aqueous ones. In particular, ethanolic extracts of Cuminum cyminum L. and Propolis expressed MIC90 values of 0.075 mg/mL. The results show a significant in vitro effect of plant extracts against H. pylori that could be considered a valuable support in the treatment of the infection and may contribute to the development of new and safe agents for inclusion in anti-H. pylori regimens.     

The pharmacological screening of Pentanisia prunelloides and the isolation of the antibacterial compound palmitic acid.

The uses of Pentanisia prunelloides in Zulu traditional medicine indicate that the plant is believed to be effective in relieving inflammation, bacterial and viral infections and also stimulating uterine contraction. Aqueous, ethanolic and ethyl acetate extracts of leaves and roots were screened for prostaglandin-synthesis inhibitors and antibacterial and antiviral activity. In the results of the anti-inflammatory assay all the extracts showed cyclooxygenase-1 inhibition. The ethanolic and ethyl acetate extracts showed greater antibacterial activity than the aqueous extracts against Gram-positive (Bacillus subtilis, Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae). Both root and leaf extracts were found to inhibit viral replication of the Influenza A virus. The ethyl acetate extract was fractionated by silica vacuum liquid chromatography and anti-inflammatory activity was found to be most pronounced in the more polar fractions. The presence of antibacterial activity was confirmed by running the fractions on a thin layer chromatography (TLC) plate and performing a bioautographic assay. The active fraction was further purified by TLC and the major antibacterial compound in the ethyl acetate root extract was identified by GC/MS as palmitic acid.     

Screening of Zulu medicinal plants for angiotensin converting enzyme (ACE) inhibitors

Twenty plants used by traditional healers in South Africa for the treatment of high blood pressure were investigated for their anti-hypertensive properties, utilizing the angiotensin converting enzyme assay. A hit rate of 65% was achieved, with the highest inhibition (97%) obtained by Adenopodia spicata leaves. A further seven plants exhibited an inhibition greater than 70% and five more over 50%. The leaves of the plants showed the greatest levels of inhibition. There was little difference in the overall hit rate between ethanolic and aqueous extracts, although in most cases there was a marked difference in activity between aqueous and ethanolic extracts from the same species. Plants exhibiting inhibition levels greater than 50% were further tested for the presence of tannins in order to eliminate possible false positives. Active plants that did not contain tannins were Agapanthus africanus, Agave americana, Clausena anisata, Dietes iridioides, Mesembruanthemum spp., Stangeria eriopus and Tulbaghia violacea.     

Anti-inflammatory and antinociceptive activity assessment of plants used as remedy in Turkish folk medicine

Ethanolic and aqueous extracts from seven plant species used in Turkish traditional medicine were evaluated for in vivo anti-inflammatory and antinociceptive activities; Helleborus orientalis Lam. roots and herbs, Juglans regia L. leaves, Laurocerasus officinalis Roemer leaves, Nerium oleander L. dried and fresh flowers and leaves, Rhododendron ponticum L. leaves, Rubus hirtus Walds. et Kit aerial parts and Rubus sanctus Schreber aerial parts and roots. All the plant extracts, except the aqueous extract of Rubus hirtus, were shown to possess significant antinociceptive activity in varying degrees against p-benzoquinone-induced abdominal contractions in mice. However, only the ethanolic extracts of Helleborus orientalis roots, Juglans regia leaves, Laurocerasus officinalis leaves, Nerium oleander dried and fresh flowers, and Rhododendron ponticum leaves exhibited potent anti-inflammatory activity against carrageenan-induced hind paw edema model in mice without inducing any gastric damage. Results of the present study confirmed the folkloric claim that all the selected materials to possess potent antinociceptive and anti-inflammatory activity.     

Studies on antibacterial, anti-inflammatory and antioxidant activity of herbal remedies used in the treatment of benign prostatic hyperplasia and prostatitis

Crude water and ethanolic extracts of five herbal remedies reported in the literature for traditional treatment of benign prostatic hyperplasia (BPH) and/or prostatitis were investigated for their effect on hydroxyl scavenging activity, antibacterial activity and their ability to inhibit cyclooxygenase-1 and -2 (COX-1 and COX-2) catalysed prostaglandin biosynthesis. Both the water and ethanol extracts of Hypoxis hemerocallidea and Epilobium parviflorum inhibited the growth of Escherichia coli. All 10 extracts scavenged the hydroxyl radical but with various potencies (32-93%). Ethanolic extracts were the most active in inhibiting COX-1 catalysed prostaglandin biosynthesis. The ethanolic extract of Epilobium parviflorum showed inhibitory effects on both the COX-1 and -2 catalysed prostaglandin biosynthesis, inhibited growth of Escherichia coli and exerted antioxidant activity. Although these results support the traditional use of Epilobium parviflorum for treatment of prostatitis and BPH, further investigation is required, for this promising plant.     

An ethnopharmacological survey and in vitro confirmation of ethnopharmacological use of medicinal plants used for wound healing in Bosomtwi-Atwima-Kwanwoma area,Ghana

Aims of the study

Wounds represent a major health burden and drain on healthcare resources in the world including Ghana and Africa. The majority of the people of Ghana and Africa still patronize traditional medicine for their health needs including various forms of wounds. The aim of this study is the identification of medicinal plants, type of wounds, dosage forms and collection methods used traditionally in treating wounds in the Bosomtwi-Atwima-Kwanwoma district, Ghana. In vitro screening of selected extracts from these plants on cell physiology of human dermal fibroblasts and keratinocytes was to be performed.

Materials and methods

Validated questionnaires were administered to 78 traditional healers in 54 communities of the district. Interviews and structured conversations were used to administer the questionnaires. Selected herbal material dominantly used by the healers was collected, identified and aqueous and ethanolic extracts were investigated in vitro on influence on cell physiology of keratinocytes and dermal fibroblasts (MTT-, BrdU-, LDH-assay). Antioxidant activities of ethanolic extracts were determined by free radical scavenging activity. Antiadhesive activity against Helicobacter pylori on human stomach cells was investigated for extracts reported to be used for stomach ulcer treatment.

Results

The ethnopharmacological survey revealed 104 plants species belonging to 47 families. The detailed use of these plants is documented. Aqueous extracts of Phyllanthus muellerianus, Pycnanthus angolensis and Combretum smeathmanni influenced the mitochondrial activity and proliferation of dermal fibroblasts and keratinocytes significantly. Ethanolic extracts of selected plants exhibited strong antioxidant activities comparable to α-tocopherol. For Spathodea campanulata, Hoslundia opposita and Pycnanthus angolensis, which were reported by the healers to be used also for wound healing in case of stomach ulcers, strong antiadhesive activity against Helicobacter pylori was demonstrated, while the extracts did not exhibit any direct cytotoxicity against the bacterium.

Conclusions

Traditional use of many wound-healing plants from Ghana can be well rationalized by the in vitro investigation of aqueous extracts. E.g. extracts of Phyllanthus muellerianus, Pycnanthus angolensis and Combretum smeathmanni exhibited significant influence on the cell viability and proliferation of keratinocytes and dermal fibroblasts.     

Antioxidant activity relates to plant part, life form and growing condition in some diabetes remedies

Selection, collection and preparation of 35 plant species used by traditional healers in the boreal regions of Canada for treatment of the symptoms of diabetes were supported empirically by antioxidant activity of the plants. Because antioxidants fluctuate with growth parameters and environmental factors, these remedies were evaluated in relation to the affect of plant part, life form and growing condition on the level of activity. The parts used here more frequently as medicines were roots and bark. Activity (IC(50)) of the bark extracts used medicinally averaged to 21.38+/-3.84 ppm while root extracts used medicinally had an IC(50) of 185.11+/-32.18 ppm in a free radical DPPH assay. In contrast the analysis of extracts of overall parts (medicinal or not) in these species found leaves and bark to have the least activity (112.22+/-30.63 ppm and 123.02+/-21.13 ppm, respectively). The highest activity was found in tree extracts (24.88+/-3.32 ppm) as compared to herbs and shrubs, and increased activity was found in plant extracts from growing conditions of decreased water/fertility. The antioxidant activity of these traditional plant remedies have the potential to be partially deduced through environment signals interpreted by the traditional herbalist.     

Antibacterial, anthelmintic and anti-amoebic activity in South African medicinal plants

Hexane, ethanol and water extracts of plants used by South African traditional healers for treating stomach ailments were screened for antibacterial, anthelmintic and anti-amoebic activities. To evaluate antibacterial activity, the disc-diffusion assay was used against several Gram-positive and Gram-negative species. Minimal inhibitory concentration values were determined with a microdilution assay. Ethanolic extracts showed the greatest activity, and Gram-positive bacteria were the most susceptible microorganisms. The free-living nematode Caenorhabditis elegans was used in two different assays to evaluate anthelmintic activity. A microdilution technique was employed to investigate anti-amoebic activity against the enteropathogenic Entamoeba histolytica. These assays were suitable for the screening of a large number of extracts at one time. Several plants exhibited significant activity against these test organisms.     

Antifungal activity of Brazilian medicinal plants involved in popular treatment of mycoses

A survey of medicinal plants used to treat common mycoses was done in the Curituba district, Sergipe State, Brazil. One hundred inhabitants were interviewed by health agents and traditional healers. Four different plants were the most cited (more than 50% of the citations): Ziziphus joazeiro, Caesalpinia pyramidalis, Bumelia sartorum and Hymenea courbaril. The aqueous extracts obtained following traditional methods and using different parts of these plants, were submitted to drop agar diffusion tests for primary antimicrobial screening. Only the water infusion extract of Ziziphus joazeiro and Caesalpinea pyramidalis presented a significant antifungal activity against Trichophyton rubrum, Candida guilliermondii, Candida albicans, Cryptococcus neoformans and Fonsecaea pedrosoi, when compared to the antifungal agent amphotericin B. The minimal inhibitory concentration (MIC) of the bioactive extracts was evaluated by the microdilution method. Best activity with a MIC of 6.5 microg/ml for both extracts was observed against Trichophyton rubrum and Candida guilliermondii. Ziziphus joazeiro and Caesalpinea pyramidalis extracts presented also low acute toxicity in murine models. The present study validates the folk use of these plant extracts and indicates that they can be effective potential candidates for the development of new strategies to treat fungal infections.