Antimicrobial activity of Terminalia macroptera root

In Vitro and Molecular Docking Evaluation of the Anticholinesterase and Antidiabetic Effects of Compounds from Terminalia macroptera Guill. & Perr. (Combretaceae)

Alzheimer's disease (AD) and diabetes are non-communicable diseases with global impacts. Inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are suitable therapies for AD, while α-amylase and α-glucosidase inhibitors are employed as antidiabetic agents. Compounds were isolated from the medicinal plant Terminalia macroptera and evaluated for their AChE, BChE, α-amylase, and α-glucosidase inhibitions. From 1H and 13C NMR data, the compounds were identified as 3,3'-di-O-methyl ellagic acid (1), 3,3',4'-tri-O-methyl ellagic acid-4-O-β-D-xylopyranoside (2), 3,3',4'-tri-O-methyl ellagic acid-4-O-β-D-glucopyranoside (3), 3,3'-di-O-methyl ellagic acid-4-O-β-D-glucopyranoside (4), myricetin-3-O-rhamnoside (5), shikimic acid (6), arjungenin (7), terminolic acid (8), 24-deoxysericoside (9), arjunglucoside I (10), and chebuloside II (11). The derivatives of ellagic acid (1-4) showed moderate to good inhibition of cholinesterases, with the most potent being 3,3'-di-O-methyl ellagic acid, with IC50 values of 46.77 ± 0.90 µg/mL and 50.48 ± 1.10 µg/mL against AChE and BChE, respectively. The compounds exhibited potential inhibition of α-amylase and α-glucosidase, especially the phenolic compounds (1-5). Myricetin-3-O-rhamnoside had the highest α-amylase inhibition with an IC50 value of 65.17 ± 0.43 µg/mL compared to acarbose with an IC50 value of 32.25 ± 0.36 µg/mL. Two compounds, 3,3'-di-O-methyl ellagic acid (IC50 = 74.18 ± 0.29 µg/mL) and myricetin-3-O-rhamnoside (IC50 = 69.02 ± 0.65 µg/mL), were more active than the standard acarbose (IC50 = 87.70 ± 0.68 µg/mL) in the α-glucosidase assay. For α-glucosidase and α-amylase, the molecular docking results for 1-11 reveal that these compounds may fit well into the binding sites of the target enzymes, establishing stable complexes with negative binding energies in the range of -4.03 to -10.20 kcalmol-1. Though not all the compounds showed binding affinities with cholinesterases, some had negative binding energies, indicating that the inhibition was thermodynamically favorable.

Phytoextracts as Antibacterials: A Review

Botanicals have been cultured to flavour food, to treat health disorders and to put a stop to diseases caused by various microorganisms. The awareness of curative features of different medicinal plants has been spread among human communities. The application of herbal products as antimicrobial agents may be a better choice for the extensive and imprudent use of synthetic antibiotics. World Health Organization recommended traditional medicines as the safest remedies for the treatment of diseases of microbial origin. The plant extracts are generally nonhazardous, available in plenty at reasonable prices, biodegradable, eco-friendly and sometimes show broad-spectrum activities against different microorganisms. The current knowledge on plant extracts, phytochemicals and their antibacterial activity, target specific mechanism of action, solvents deployed during extraction, properties of an active ingredient isolated may help in biological control of bacteria. Antimicrobial properties of different plant parts, which act in a low dose, have been organised separately for easy understanding.

Campylobacter: A Review of New Promising Remedies with Medicinal Plants and Natural Antioxidants

Campylobacter (curved bacteria) is considered one of the most important and common zoonotic bacteria and the three leading bacterial causes of gastroenteritis and diarrhea. Antibacterial resistance is growing and expanding. The aim of this review article is to report anti-Campylobacter medicinal plants. For this purpose, the search terms consisting of Campylobacter, medicinal plants, essential oil, extract, and traditional medicine were used to retrieve the relevant articles published in the journals indexed in Information Sciences Institute, Web of Science, PubMed, Scopus, Google Scholar, and Scientific Information Databases. Then, the findings of eligible articles were analyzed. According to the analysis, 71 medicinal plants were found to exert anti-Campylobacter effect. The active compounds of these plants are possibly nature-based antibiotic agents that are effective on Campylobacter. If these compounds are isolated, purified, and studied in pharmaceutical investigations, they can be used to produce nature-based, anti-Campylobacter antibiotics.

Potential Role of Plant Extracts and Phytochemicals Against Foodborne Pathogens

Foodborne diseases are one of the major causes of morbidity and mortality, especially in low-income countries with poor sanitation and inadequate healthcare facilities. The foremost bacterial pathogens responsible for global outbreaks include Salmonella species, Campylobacter jejuni, Escherichia coli, Shigella sp., Vibrio, Listeria monocytogenes and Clostridium botulinum. Among the viral and parasitic pathogens, norovirus, hepatitis A virus, Giardia lamblia, Trichinella spiralis, Toxoplasma and Entamoeba histolytica are commonly associated with foodborne diseases. The toxins produced by Staphylococcus aureus, Bacillus cereus and Clostridium perfringens also cause these infections. The currently available therapies for these infections are associated with various limited efficacy, high cost and side-effects. There is an urgent need for effective alternative therapies for the prevention and treatment of foodborne diseases. Several plant extracts and phytochemicals were found to be highly effective to control the growth of these pathogens causing foodborne infections in in vitro systems. The present review attempts to provide comprehensive scientific information on major foodborne pathogens and the potential role of phytochemicals in the prevention and treatment of these infections. Further detailed studies are necessary to evaluate the activities of these extracts and phytochemicals along with their mechanism of action using in vivo models.

A Systematic Review of In Vitro Activity of Medicinal Plants from Sub-Saharan Africa against Campylobacter spp

Introduction

Campylobacter spp. are zoonotic bacteria that cause gastroenteritis in humans and may cause extraintestinal infections such as Guillain-Barré syndrome, reactive arthritis, and bacteremia. Resistance to antibiotics is an increasing concern in the Sub-Saharan Africa; thus, search for alternatives such as plant-based active ingredients is important in order to develop new drugs.

Objectives

To present a systematic review of in vitro and in vivo studies of the antibacterial activity of medicinal plants from Sub-Saharan Africa against Campylobacter spp. Methodology. Studies published until March 2020 on medicinal plants used against Campylobacter spp. from each country of Sub-Saharan Africa were searched on PubMed, Science Direct, AJOL, and Google Scholar. Articles were selected based on the existence of information regarding in vitro and in vivo activity of medicinal plants against Campylobacter spp.

Results

A total of 47 medicinal plants belonging to 28 families were studied for in vitro activity against Campylobacter spp. No plant was studied in vivo. Plants from Fabaceae family were the most commonly studied. The plants with the strongest antimicrobial activities were Cryptolepis sanguinolenta and Terminalia macroptera. The root extracts from these plants were effective, and both had a minimal inhibitory concentration (MIC) of 25 μg/ml. Seven pure compounds were isolated and analyzed for activity against Campylobacter spp. The compound cryptolepine from C. sanguinolenta was the most effective with MIC values ranging between 6.25 and 25 μg/ml.

Conclusion

Several native plants from the Sub-Saharan Africa region were studied for in vitro activity against Campylobacter spp. Some plants seemed very effective against the bacteria. Chemical compounds from three plants have been isolated and analyzed, but further studies are needed in order to produce new and effective drugs.

Pomegranate peel as phenolic compounds source: Advanced analytical strategies and practical use in meat products

The growing demand for natural food preservatives has promoted investigations on their application for preserving perishable foods. Consequently, the meat market is demanding natural antioxidants, free of synthetic additives and able to diminish the oxidation processes in high-fat meat and meat products. In this context, the present review discuss the development of healthier and shelf stable meat products by the successful use of pomegranate peel extracts containing phenolics as natural preservative agent in meat and meat products. This paper carries out an exhaustive review of the scientific literature on the main active phenolic compounds of pomegranate peel identified and quantified by advances in the separation sciences and spectrometry, and its biological activities evaluation. Moreover, the impact of pomegranate peel use on the quality and oxidative stability of meat products is also evaluated. As natural preservative, pomegranate peel phenolics could improve stored meat products quality, namely instrumental color retaining, limitaion of microflora growth, retardation of lipid and protein oxidation.

In vivo validation of anti-malarial activity of crude extracts of Terminalia macroptera, a Malian medicinal plant

BACKGROUND

Plasmodium falciparum malaria is still one of the most deadly pathology worldwide. Efficient treatment is jeopardized by parasite resistance to artemisinin and its derivatives, and by poor access to treatment in endemic regions. Anti-malarial traditional remedies still offer new tracks for identifying promising antiplasmodial molecules, and a way to ensure that all people have access to care. The present study aims to validate the traditional use of Terminalia macroptera, a Malian plant used in traditional medicine.

METHODS

Terminalia macroptera was collected in Mali. Leaves (TML) and roots ethanolic extracts (TMR) were prepared and tested at 2000 mg/kg for in vivo acute toxicity in Albino Swiss mice. Antiplasmodial activity of the extracts was assessed against a chloroquine resistant strain P. falciparum (FcB1) in vitro. In vivo, anti-malarial efficacy was assessed by a 4-day suppressive test at 100 mg/kg in two malaria murine models of uncomplicated malaria (Plasmodium chabaudi chabaudi infection) and cerebral malaria (Plasmodium berghei strain ANKA infection). Constituents of TMR were characterized by ultra-high-performance liquid chromatography coupled to high resolution mass spectrometry. Top ranked compounds were putatively identified using plant databases and in silico fragmentation pattern.

RESULTS

Lethal dose of TML and TMR were greater than 2000 mg/kg in Albino Swiss mice. According to the OECD's Globally Harmonized System of Classification, both extracts are non-toxic orally. Antiplasmodial activity of T. macroptera extracts was confirmed in vitro against P. falciparum FcB1 strain with IC50 values of 1.2 and 1.6 µg/mL for TML and TMR, respectively. In vivo, oral administration of TML and TMR induced significant reduction of parasitaemia (37.2 and 46.4% respectively) in P. chabaudi chabaudi infected mice at the 7th day of infection compared to untreated mice. In the cerebral malaria experimental model, mice treated with TMR and TML presented respectively 50 and 66.7% survival rates at day 9 post-infection when all untreated mice died. Eleven major compounds were found in TMR. Among them, several molecules already known could be responsible for the antiplasmodial activity of the roots extract of T. macroptera.

CONCLUSIONS

This study confirms both safety and anti-malarial activity of T. macroptera, thus validating its traditional use.

Ellagitannin HeT obtained from strawberry leaves is oxidized by bacterial membranes and inhibits the respiratory chain

Plant secondary metabolism produces a variety of tannins that have a wide range of biological activities, including activation of plant defenses and antimicrobial, anti‐inflammatory and antitumoral effects. The ellagitannin HeT (1‐O‐galloyl‐2,3;4,6‐bis‐hexahydroxydiphenoyl‐β‐d‐glucopyranose) from strawberry leaves elicits a strong plant defense response, and exhibits antimicrobial activity associated to the inhibition of the oxygen consumption, but its mechanism of action is unknown. In this paper we investigate the influence of HeT on bacterial cell membrane integrity and its effect on respiration. A β‐galactosidase unmasking experiment showed that HeT does not disrupt membrane integrity. Raman spectroscopy analysis revealed that HeT strongly interacts with the cell membrane. Spectrochemical analysis indicated that HeT is oxidized in contact with bacterial cell membranes, and functional studies showed that HeT inhibits oxygen consumption, NADH and MTT reduction. These results provide evidence that HeT inhibits the respiratory chain.

LC-MS/MS Tandem Mass Spectrometry for Analysis of Phenolic Compounds and Pentacyclic Triterpenes in Antifungal Extracts of Terminalia brownii (Fresen)

Decoctions and macerations of the stem bark and wood of Terminalia brownii Fresen. are used in traditional medicine for fungal infections and as fungicides on field crops and in traditional granaries in Sudan. In addition, T. brownii water extracts are commonly used as sprays for protecting wooden houses and furniture. Therefore, using agar disc diffusion and macrodilution methods, eight extracts of various polarities from the stem wood and bark were screened for their growth-inhibitory effects against filamentous fungi commonly causing fruit, vegetable, grain and wood decay, as well as infections in the immunocompromised host. Ethyl acetate extracts of the stem wood and bark gave the best antifungal activities, with MIC values of 250 µg/mL against Nattrassia mangiferae and Fusarium verticillioides, and 500 µg/mL against Aspergillus niger and Aspergillus flavus. Aqueous extracts gave almost as potent effects as the ethyl acetate extracts against the Aspergillus and Fusarium strains, and were slightly more active than the ethyl acetate extracts against Nattrassiamangiferae. Thin layer chromatography, RP-HPLC-DAD and tandem mass spectrometry (LC-MS/MS), were employed to identify the chemical constituents in the ethyl acetate fractions of the stem bark and wood. The stem bark and wood were found to have a similar qualitative composition of polyphenols and triterpenoids, but differed quantitatively from each other. The stilbene derivatives, cis- (3) and trans- resveratrol-3-O-β-galloylglucoside (4), were identified for the first time in T. brownii. Moreover, methyl-(S)-flavogallonate (5), quercetin-7-β-O-di-glucoside (8), quercetin-7-O-galloyl-glucoside (10), naringenin-4'-methoxy-7-pyranoside (7), 5,6-dihydroxy-3',4',7-tri-methoxy flavone (12), gallagic acid dilactone (terminalin) (6), a corilagin derivative (9) and two oleanane type triterpenoids (1) and (2) were characterized. The flavonoids, a corilagin derivative and terminalin, have not been identified before in T. brownii. We reported earlier on the occurrence of methyl-S-flavogallonate and its isomer in the roots of T. brownii, but this is the first report on their occurrence in the stem wood as well. Our results justify the traditional uses of macerations and decoctions of T. brownii stem wood and bark for crop and wood protection and demonstrate that standardized extracts could have uses for the eco-friendly control of plant pathogenic fungi in African agroforestry systems. Likewise, our results justify the traditional uses of these preparations for the treatment of skin infections caused by filamentous fungi.

Ethnopharmacology, Chemistry and Biological Properties of Four Malian Medicinal Plants

The ethnopharmacology, chemistry and pharmacology of four Malian medicinal plants, Biophytum umbraculum, Burkea africana, Lannea velutina and Terminalia macroptera are reviewed. These plants are used by traditional healers against numerous ailments: malaria, gastrointestinal diseases, wounds, sexually transmitted diseases, insect bites and snake bites, etc. The scientific evidence for these uses is, however, limited. From the chemical and pharmacological evidence presented here, it seems possible that the use in traditional medicine of these plants may have a rational basis, although more clinical studies are needed.

Medicinal plants of Guinea-Bissau: Therapeutic applications, ethnic diversity and knowledge transfer

ETHNOPHARMACOLOGICAL RELEVANCE

The rich flora of Guinea-Bissau, and the widespread use of medicinal plants for the treatment of various diseases, constitutes an important local healthcare resource with significant potential for research and development of phytomedicines. The goal of this study is to prepare a comprehensive documentation of Guinea-Bissau's medicinal plants, including their distribution, local vernacular names and their therapeutic and other applications, based upon local notions of disease and illness.

MATERIALS AND METHODS

Ethnobotanical data was collected by means of field research in Guinea-Bissau, study of herbarium specimens, and a comprehensive review of published works. Relevant data were included from open interviews conducted with healers and from observations in the field during the last two decades.

RESULTS

A total of 218 medicinal plants were documented, belonging to 63 families, of which 195 are native. Over half of these species are found in all regions of the country. The medicinal plants are used to treat 18 major diseases categories; the greatest number of species are used to treat intestinal disorders (67 species). More than thirty ethnic groups were identified within the Guinea-Bissau population; 40% of the medicinal plants have been recorded in the country's principal ethnic languages (i.e. Fula and Balanta).

CONCLUSIONS

This multi-disciplinary, country-wide study identifies a great diversity of plants used by indigenous communities as medicinal, which constitute an important common reservoir of botanical species and therapeutic knowledge. The regional overlap of many indigenous species, the consensual nature of disease groups based upon local perceptions of health conditions, and the relevance of local vernacular including Guinean Creole are key factors specific to the country which enhance the potential for the circulation and transmission of ethno-botanical and therapeutic knowledge.

Formation of β-glucogallin, the precursor of ellagic acid in strawberry and raspberry

Ellagic acid/ellagitannins are plant polyphenolic antioxidants that are synthesized from gallic acid and have been associated with a reduced risk of cancer and cardiovascular diseases. Here, we report the identification and characterization of five glycosyltransferases (GTs) from two genera of the Rosaceae family (Fragaria and Rubus; F. × ananassa FaGT2*, FaGT2, FaGT5, F. vesca FvGT2, and R. idaeus RiGT2) that catalyze the formation of 1-O-galloyl-β-D-glucopyranose (β-glucogallin) the precursor of ellagitannin biosynthesis. The enzymes showed substrate promiscuity as they formed glucose esters of a variety of (hydroxyl)benzoic and (hydroxyl)cinnamic acids. Determination of kinetic values and site-directed mutagenesis revealed amino acids that affected substrate preference and catalytic activity. Green immature strawberry fruits were identified as the main source of gallic acid, β-glucogallin, and ellagic acid in accordance with the highest GT2 gene expression levels. Injection of isotopically labeled gallic acid into green fruits of stable transgenic antisense FaGT2 strawberry plants clearly confirmed the in planta function. Our results indicate that GT2 enzymes might contribute to the production of ellagic acid/ellagitannins in strawberry and raspberry, and are useful to develop strawberry fruit with additional health benefits and for the biotechnological production of bioactive polyphenols.

The malaria co-infection challenge: An investigation into the antimicrobial activity of selected Guinean medicinal plants

ETHNOPHARMACOLOGICAL RELEVANCE

In sub-Saharan Africa, concomitant occurrence of malaria and invasive infections with micro-organisms such as Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli and yeasts or fungi such as Candida albicans and Aspergillus fumigatus is common. Non-tuberculous mycobacteriosis caused by Mycobacterium chelonae has been recognized as a pulmonary pathogen with increasing frequency without effective therapy. Although less important, the high incidence of Trichophyton rubrum infections along with its ability to evade host defense mechanisms, accounts for the high prevalence of infections with this dermatophyte. Considering the treatment cost of both malaria and microbial infections, along with the level of poverty, most affected African countries are unable to cope with the burden of these diseases. In sub-Saharan Africa, many plant species are widely used in the treatment of these diseases which are traditionally diagnosed through the common symptom of fever. Therefore it is of interest to evaluate the antimicrobial activities of medicinal plants reported for their use against malaria/fever.

MATERIALS AND METHODS

Based on an ethnobotanical survey, 34 Guinean plant species widely used in the traditional treatment of fever and/or malaria have been collected and evaluated for their antimicrobial activities. Plants extracts were tested against Candida albicans, Trichophyton rubrum, Aspergillus fumigatus, Mycobacterium chelonae, Staphylococcus aureus and Escherichia coli.

RESULTS

The most interesting activities against Candida albicans were obtained for the polar extracts of Pseudospondias microcarpa and Ximenia americana with IC50 values of 6.99 and 8.12 µg/ml, respectively. The most pronounced activity against Trichophyton rubrum was obtained for the ethanol extract of Terminalia macroptera (IC50 5.59 µg/ml). Only 7 of the 51 tested extracts were active against Staphylococcus aureus. From these, the methanolic extracts of the leaves and stem bark of Alchornea cordifolia were the most active with IC50 values of 2.81 and 7.47 µg/ml, respectively. Only Terminalia albida and Lawsonia inermis showed activity against Mycobacterium chelonae. None of the tested extracts was active against Escherichia coli.

CONCLUSION

A number of traditional Guinean plant species used against malaria/fever showed, in addition to their antiplasmodial properties and antimicrobial activity. The fact that some plant species are involved in the traditional treatment of malaria/fever without any antiplasmodial evidence may be justified by their antimicrobial activities.

Enzyme inhibition, antioxidant and immunomodulatory activities, and brine shrimp toxicity of extracts from the root bark, stem bark and leaves of Terminalia macroptera

ETHNOPHARMACOLOGICAL RELEVANCE

The root bark, stem bark and leaves of Terminalia macroptera have been traditionally used against a variety of ailments such as wounds, hepatitis, malaria, fever, cough, and diarrhea as well as tuberculosis and skin diseases in African folk medicine. Boiling water extracts of Terminalia macroptera, administered orally, are the most common preparations of this plant used by the traditional healers in Mali. This study aimed to investigate the inhibition of the activities of α-glucosidase, 15-lipoxygenase and xanthine oxidase, DPPH scavenging activity, complement fixation activity and brine shrimp toxicity of different extracts obtained by boiling water extraction (BWE) and by ASE (accelerated solvent extraction) with ethanol, ethanol-water and water as extractants from different plant parts of Terminalia macroptera.

MATERIALS AND METHODS

27 different crude extracts were obtained by BWE and ASE from root bark, stem bark and leaves of Terminalia macroptera. The total phenolic and carbohydrate contents, enzyme inhibition activities (α-glucosidase, 15-lipoxygenase and xanthine oxidase), DPPH scavenging activity, complement fixation activity and brine shrimp toxicity of these extracts were evaluated. Principal component analysis (PCA) was applied for total biological activities evaluation.

RESULTS

Several of the extracts from root bark, stem bark and leaves of Terminalia macroptera obtained by BWE and ASE showed potent enzyme inhibition activities, radical-scavenging properties and complement fixation activities. None of the extracts are toxic against brine shrimp larvae in the test concentration. Based on the results from PCA, the ASE ethanol extracts of root bark and stem bark and the low molecular weight fraction of the 50% ethanol-water extract of leaves showed the highest total biological activities. The boiling water extracts were less active, but the bark extracts showed activity as α-glucosidase inhibitors and radical scavengers, the leaf extract being less active.

CONCLUSION

The observed enzyme inhibition activities, radical scavenging properties and complement fixation activities may explain some of the traditional uses of this medicinal tree, such as in wound healing and against diabetes.

Complement activity of polysaccharides from three different plant parts of Terminalia macroptera extracted as healers do

ETHNOPHARMACOLOGICAL RELEVANCE

Water decoctions of the root bark, stem bark and leaves of Terminalia macroptera are used by traditional healers in Mali to cure a wide range of illnesses, such as wounds, hepatitis, malaria, fever, cough and diarrhea as well as tuberculosis. Plant polysaccharides isolated from crude water extracts have previously shown effects related to the immune system. The aims of this study are comparing the properties of the polysaccharides among different plant parts, as well as relationship between chemical characteristics and complement fixation activities when the plant material has been extracted as the traditional healers do, with boiling water directly.

MATERIALS AND METHODS

Root bark, stem bark and leaves of Terminalia macroptera were extracted by boiling water, and five purified polysaccharide fractions were obtained by anion exchange chromatography and gel filtration. Chemical compositions were determined by GC of the TMS derivatives of the methyl-glycosides and the linkage determined after permethylation and GC-MS of the derived partly methylated alditol acetates. The bioactivity was determined by the complement fixation assay of the crude extracts and purified fractions.

RESULTS

The acidic fraction TRBD-I-I isolated from the root bark was the most active of the fractions isolated. Structural studies showed that all purified fractions are of pectic nature, containing rhamnogalacturonan type I backbone. Arabinogalactan type II side chains were present in all fractions except TRBD-I-II. The observed differences in complement fixation activities among the five purified polysaccharide fractions are probably due to differences in monosaccharide compositions, linkage types and molecular sizes.

CONCLUSION

The crude extracts from root bark and stem bark have similar total activities, both higher than those from leaves. The root bark, leaves and stem bark are all good sources for fractions containing bioactive polysaccharides. But due to sustainability, it is prefer to use leaves rather than the other two plant parts, and then the dosage by weight must be higher when using leaves.

Complement fixing polysaccharides from Terminalia macroptera root bark, stem bark and leaves

The root bark, stem bark and leaves of Terminalia macroptera were sequentially extracted with ethanol, 50% ethanol-water, and 50 °C and 100 °C water using an accelerated solvent extractor. Ten bioactive purified polysaccharide fractions were obtained from those crude extracts after anion exchange chromatography and gel filtration. The polysaccharides and their native extracts were characterized with respect to molecular weight, chemical compositions and effects in the complement assay. The chemical compositions showed that the polysaccharides are of pectic nature. The results indicated that there was no great difference of the complement fixation activities in the crude extracts from the different plant parts when extracting with the accelerated solvent extraction system. The purified polysaccharide fractions 100WTSBH-I-I and 100WTRBH-I-I isolated from the 100 °C water extracts of stem and root bark respectively, showed the highest complement fixation activities. These two fractions have rhamnogalacturonan type I backbone, but only 100WTSBH-I-I contains side chains of both arabinogalactan type I and II. Based on the yield and activities of the fractions studied those from the root bark gave highest results, followed by those from leaves and stem bark. But in total, all plant materials are good sources for fractions containing bioactive polysaccharides.

A bioactivity versus ethnobotanical survey of medicinal plants from Nigeria, west Africa

Traditional medicinal practices play a key role in health care systems in countries with developing economies. The aim of this survey was to validate the use of traditional medicine within local Nigerian communities. In this review, we examine the ethnobotanical uses of selected plant species from the Nigerian flora and attempt to correlate the activities of the isolated bioactive principles with known uses of the plant species in African traditional medicine. Thirty-three (33) plant species were identified and about 100 out of the 120 compounds identified with these plants matched with the ethnobotanical uses of the plants.

The uniqueness and therapeutic value of natural products from West African medicinal plants, part III: least abundant compound classes

In this review, a continuation of our in-depth coverage of natural products derived from West African medicinal plants with diverse biological activities has been given.

The uniqueness and therapeutic value of natural products from West African medicinal plants. Part I: uniqueness and chemotaxonomy

This review gives an in depth coverage of the natural products derived from West African medicinal plants with diverse biological activities.

The uniqueness and therapeutic value of natural products from West African medicinal plants, part II: terpenoids, geographical distribution and drug discovery

In this review series, an attempt has been made to give indepth coverage of natural products derived from West African medicinal plants with diverse biological activities.

Screening Togolese medicinal plants for few pharmacological properties

Background:

Terminalia macroptera Guill. et Perr. (Combretaceae), Sida alba L. (Malvaceae), Prosopis africana Guill et Perr. Taub. (Mimosaceae), Bridelia ferruginea Benth. (Euphorbiaceae), and Vetiveria nigritana Stapf. (Asteraceae) are traditionally used in Togolese folk medicine to treat several diseases including microbial infections.

Objective:

This study aimed to investigate the antimicrobial, antioxidant, and hemolytic properties of the crude extracts of the above-mentioned plants.

Materials and Methods:

The antimicrobial and the antioxidant activities were assayed using the NCCLS microdilution method and the DPPH free radical scavenging, respectively. Human A+ red blood cells were used to perform the hemolytic assay. Phenolics were further quantified in the extracts using spectrophotometric methods.

Results:

Minimal inhibitory concentrations in the range of 230-1800 μg/ml were recorded in the NCCLS broth microdilution for both bacterial and fungal strains with methanol extracts. The DPPH radical scavenging assay yielded interesting antioxidant activities of the extracts of P. africana and T. macroptera (IC₅₀ values of 0.003 ± 0.00 μg/ml and 0.05 ± 0.03 μg/ml, respectively). These activities were positively correlated with the total phenolic contents and negatively correlated with the proanthocyanidin content of the extracts. The hemolytic assay revealed that great hemolysis occurred with the methanol extracts of T. macroptera, S. longepedunculata, and B. ferruginea.

Conclusion:

These results support in part the use of the selected plants in the treatment of microbial infections. In addition, the plant showed an interesting antioxidant activity that could be useful in the management of oxidative stress.

Anti-Helicobacter pylori activity of Terminalia macroptera root

The root of Terminalia macroptera Guill. & Perr. (Combretaceae) is widely used in African traditional medicine to treat various infectious diseases, including stomach-associated diseases. This study investigates the in vitro activity of T. macroptera root extract against reference strains and clinical isolates of H. pylori and attempts to localize the extract bioactivity. T. macroptera hydroethanol (80% V/V) root extract (Tmr) activity was tested against three standard strains and sixty two clinical strains of H. pylori. Tmr liquid-liquid partition fractions were screened against twenty H. pylori strains. Qualitative analysis of Tmr and its fractions was performed by HPLC-UV/DAD. The antibiotic characterization of the H. pylori strains revealed that 20% of the tested clinical isolates were resistant to at least two of the three antibiotics belonging to the main groups of antibiotics used in multi-therapy to eradicate H. pylori infections. In contrast, Tmr showed anti-H. pylori activity against the majority (92%) of the tested strains (MIC(50) and MIC(90)=200 μg/ml). The Tmr water liquid-liquid fraction (Tmr-3) and the precipitate obtained from this fraction (Tmr-5) were the most active tested samples, showing a MIC(50) of 100 μg/ml. The present work proves the in vitro activity of T. macroptera against H. pylori, thus confirming the utility of this traditional medicinal plant to treat stomach complaints due to H. pylori infection. The main compounds of Tmr and of Tmr-3 were the ellagitannins terchebulin and punicalagin. These compounds can be considered as markers of T. macroptera root active extracts against H. pylori.

Gastroprotective effect of Senecio candicans DC on experimental ulcer models

ETHNOPHARMACOLOGICAL RELEVANCE

Senecio candicans DC (Asteraceae) is used as a remedy for gastric ulcer and stomach pain in the Nilgiris district, Tamil Nadu for which no scientific evidence exists.

AIM OF THE STUDY

The present study was performed to evaluate the gastroprotective effects and acute oral toxicity of aqueous leaf extract of Senecio candicans (AESC) in experimental models.

MATERIALS AND METHODS

The antiulcerogenic activity of AESC was performed in two different ulcer models viz., pylorus-ligated model and ethanol-induced model using Wistar albino rats. Acute toxicity study was also performed to get information on the admissible dose for treatment of ulcer. Preliminary phytochemical screening of AESC was performed to find the active principles present, which are thus responsible for the antiulcerogenic activity. DPPH assay was performed to confirm the antioxidant activity of AESC.

RESULTS

The acute toxicity study did not show any mortality up to 2500mg/kg b.w. of AESC. Both the ulcer models showed gastroprotective effect comparable to that of the standard Omeprazole. The results of antioxidant enzymes, histopathology sections, ATPase and mucus content of gastric secretion showed that several mechanisms are involved in the gastroprotective effect. The preliminary phytochemical screening revealed the presence of alkaloids, flavonoids and steroids in AESC. The DPPH assay confirmed the antioxidant activity of AESC.

CONCLUSION

The traditional consumption of AESC for the treatment of gastric ulcer is thus true, the antioxidant constituents present in the extract plays a major role in the gastroprotective activity, but since Senecio species are known for the presence of pyrrolizidine alkaloids, a detailed study in future is required to describe the safe dose for a prolonged period.

An Overview of Antimicrobial Properties of Different Classes of Phytochemicals

Plants produce a great diversity of phytochemicals, the beneficial properties of which have been used by humans for centuries since the advent of human civilization. With the discovery of effective and potent antimicrobial compounds, these synthetic antimicrobial compounds are widely used to prevent and cure microbial diseases. However, the development of antibiotic resistant strains of bacteria, reduced efficacy and safety of antimicrobials and the search of new antimicrobials against emerging incurable diseases by conventional antimicrobial agents have revived to explore phytochemicals as an alternative to synthetic antimicrobial compounds. Although numerous studies have been conducted in vitro and in vivo in the recent years on the efficacy of plant phytochemicals as antimicrobial agents, this chapter provides an overview of the antimicrobial properties of some major group of phytochemicals, namely, different phenolic compounds, alkaloids, saponins, iridoids and secoiridoids, polyacetylenes, glucosinolates, terpenoids, sulfinate, limonoids (tetranortepenoids) and anthranoids against pathogenic bacteria, fungi, viruses and commensal bacteria in the intestinal tracts of humans and animals. This chapter also discusses their antimicrobial mechanisms of action, the efficiency of different groups of phytochemicals against multiple-drug resistant bacteria, the effect of active dietary phytometabolites on the beneficial and pathogenic microbes of the gastrointestinal tracts and the outcomes of combination of phytofactors and drugs interactions.

Prophylactic effect of Andrographis paniculata extracts against Streptococcus agalactiae infection in Nile tilapia (Oreochromis niloticus)

Six herbs were assessed for their antimicrobial activity against Streptococcus agalactiae, a major fish pathogen causing streptococcosis. Each herb was extracted with 3 solvents: water, 95% ethanol, and methanol. Using swab paper disc assays, aqueous extracts of Andrographis paniculata and Allium sativum produced the largest (27.5 mm) and smallest (10.3 mm) inhibition zones, respectively. Determination of minimal inhibitory concentration (MIC) of herb extracts against S. agalactiae showed that the aqueous extract of A. paniculata had the lowest MIC value (31.25 microg/mL). Aqueous extract of A. sativum was the only herb extract with a MIC > 500 microg/mL. Based on mortalities in 2 weeks after intraperitoneal S. agalactiae injection, the median lethal dose (LD(50)) of S. agalactiae for Nile tilapia (Oreochromis niloticus) was 3.79 x 10(5) CFU/mL. In vivo experiments showed that fish feed supplemented with either A. paniculata leaf powder or dried matter of A. paniculata aqueous extract reduced mortality of S. agalactiae infected Nile tilapia. In addition, no mortality was found in fish receiving dried matter of A. paniculata aqueous extract supplemented feeds at ratios (w/w) of 4:36 and 5:35. During 2 weeks of feeding with A. paniculata supplemented feeds, no adverse effects on appearance, behavior, or feeding responses were observed.

Antifungal activities of five Combretaceae used in Togolese traditional medicine

Five species of Combretaceae growing in Togo were investigated for their antifungal activity against 20 pathogenic fungi (10 yeast and 10 filamentous fungi). The five hydroethanolic extracts of Terminalia glaucescens and Anogeissus leiocarpus appeared to be the most active, their MICs ranging from 0.25 mg/ml to 4 mg/ml. The results confirm the traditional therapeutic properties of these plants.

Studies on antibacterial, antioxidant and fibroblast growth stimulation of wound healing remedies from South Africa

Aqueous and methanol extracts of Urtica urens, Capparis tomentosa, Dicoma anomala, Leonotis leonorus, Xysmalobium undulatum, Helichrysum foetidum, Pterocarpus angolensis, Terminalia sericea and Gunnera perpensa, plants documented as being used for topical wound healing in the literature, were tested for antibacterial activity against Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli and Pseudomonas aeruginosa. Methanol and water extracts of two of these plants, Terminalia sericea and Gunnera perpensa, were more active compared to the other extracts against Streptococcus pyogenes and Staphylococcus aureus. The effects of the latter plants on fibroblast growth as well as oxidant production by N-formyl-methionyl-leucyl-phenylalanine were also studied. The water and methanol extracts of Terminalia sericea and Gunnera perpensa significantly decreased luciginin enhanced chemiluminescence at concentrations of 100 microg/ml and higher. However, the extracts had no effect on the growth of primary human fibroblasts.

Potential therapeutic applications of some antinutritional plant secondary metabolites

Plant-based formulations have been used since ancient times as remedial measures against various human and animal ailments. Over the past 20 years interest in traditional medicines has increased considerably in many parts of the world. Whereas modifications in lifestyles, including diet, have had a profound effect on the increased risks of various diseases, there is considerable scientific evidence, both epidemiological and experimental, regarding vegetables and fruits as key features of diets associated with reduced risks of diseases such as cancers and infections. This has led to the use of a number of phytometabolites as anticarcinogenic and cardioprotective agents, promoting a dramatic increase in their consumption as dietary supplements. There are changing perceptions regarding the therapeutic potential of various plant secondary metabolites (PSMs), some of which have also been known to possess certain antinutritional qualities. The knowledge gained at the cellular and molecular levels, and biological activities of PSMs including tannin-polyphenols, saponins, mimosine, flavonoids, terpenoids, and phytates, would be useful in planning for future epidemiological studies and human cancer prevention trials, especially when a large pure dosage is not the option to deliver the active compounds to many tissues. It is well observed that alteration of cell cycle regulatory gene expression is frequently found in tumor tissues or cancer cell lines, and studies have suggested that the herbal-based or plant-originated cell cycle regulators might represent a new set of potential targets for anticancer drugs. The recent upsurge of interest in this area of research and advances made therein indicate that the impact of a number of diseases affecting humans and animals may be lessened, if not prevented, by simple dietary intake of PSMs with putative therapeutic properties.

In vitro anti-Neisseria gonorrhoeae activity of Terminalia macroptera leaves

We used the agar dilution method to evaluate the antibacterial effect of Terminalia macroptera leaf (Tml) extract against nine reference and clinical Neisseria gonorrhoeae strains, including penicillin- and tetracycline-resistant and -susceptible strains. Tml possesses anti-N. gonorrhoeae activity against all of the strains and the minimum inhibitory concentrations (MIC) were between 100 and 200 microg ml(-1). We then used a liquid-liquid partition method to divide the Tml extract into five fractions and determined the anti-N. gonorrhoeae activity of each of the fractions. All of the fractions showed antibacterial activity. The most active one was identified as the diethyl ether fraction and had MIC values of between 25 and 50 microg ml(-1) against all of the strains.

In vitro anti-Neisseria gonorrhoeae activity of Terminalia macroptera leaves

We used the agar dilution method to evaluate the antibacterial effect of Terminalia macroptera leaf (Tml) extract against nine reference and clinical Neisseria gonorrhoeae strains, including penicillin- and tetracycline-resistant and -susceptible strains. Tml possesses anti-N. gonorrhoeae activity against all of the strains and the minimum inhibitory concentrations (MIC) were between 100 and 200 microg ml(-1). We then used a liquid-liquid partition method to divide the Tml extract into five fractions and determined the anti-N. gonorrhoeae activity of each of the fractions. All of the fractions showed antibacterial activity. The most active one was identified as the diethyl ether fraction and had MIC values of between 25 and 50 microg ml(-1) against all of the strains.

Antimicrobial properties of phenolic compounds from berries

AIMS

To investigate the antimicrobial properties of phenolic compounds present in Finnish berries against probiotic bacteria and other intestinal bacteria, including pathogenic species.

METHODS AND RESULTS

Antimicrobial activity of pure phenolic compounds representing flavonoids and phenolic acids, and eight extracts from common Finnish berries, was measured against selected Gram-positive and Gram-negative bacterial species, including probiotic bacteria and the intestinal pathogen Salmonella. Antimicrobial activity was screened by an agar diffusion method and bacterial growth was measured in liquid culture as a more accurate assay. Myricetin inhibited the growth of all lactic acid bacteria derived from the human gastrointestinal tract flora but it did not affect the Salmonella strain. In general, berry extracts inhibited the growth of Gram-negative but not Gram-positive bacteria. These variations may reflect differences in cell surface structures between Gram-negative and Gram-positive bacteria. Cloudberry, raspberry and strawberry extracts were strong inhibitors of Salmonella. Sea buckthorn berry and blackcurrant showed the least activity against Gram-negative bacteria.

CONCLUSION

Different bacterial species exhibit different sensitivities towards phenolics.

SIGNIFICANCE AND IMPACT OF THE STUDY

These properties can be utilized in functional food development and in food preservative purposes.

Application of high performance liquid chromatography coupled with ultraviolet spectroscopy and electrospray mass spectrometry to the characterisation of ellagitannins from Terminalia macroptera roots

PURPOSE

Terminalia macroptera roots are used in Guinea-Bissau and other West African countries to treat infectious diseases like gonorrhoea. Previous work showed an ethanol extract of T. macroptera roots (T) to have an in vitro antimicrobial profile against Neisseria gonorrhoae (including resistant strains) and enteropathogenic agents. The most active fractions of this extract were identified as the diethyl ether (T2) and water (T5) fractions. The aim of the present study was the identification of major compounds present in T and simultaneously in T2 or T5.

METHODS

The T extract and T2 and T5 fractions were analysed by high performance liquid chromatography coupled with ultraviolet photodiode array (LC-UV) spectroscopy and electrospray ionization mass spectrometry (ES-MS). These analyses indicated the presence of ellagitannin derivatives. In order to confirm the identities of the detected compounds, they were isolated from T2 and T5 by preparative chromatographic techniques and identified by spectroscopic methods including tandem mass spectrometry.

RESULTS

By using LC-UV-ES-MS, four major compounds (ellagic acid, gallic acid, punicalagin, terchebulin) could be identified in the T extract. Three other compounds (3,3'di-O-methylellagic acid, 3,4,3',4'-tetra-O-methylellagic acid, terflavin A) were also isolated and identified.

CONCLUSIONS

LC-UV-ES-MS is a useful technique for the analysis of mixtures containing ellagitannins.

Plant products as antimicrobial agents

The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Ethnopharmacologists, botanists, microbiologists, and natural-products chemists are combing the Earth for phytochemicals and "leads" which could be developed for treatment of infectious diseases. While 25 to 50% of current pharmaceuticals are derived from plants, none are used as antimicrobials. Traditional healers have long used plants to prevent or cure infectious conditions; Western medicine is trying to duplicate their successes. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. This review attempts to summarize the current status of botanical screening efforts, as well as in vivo studies of their effectiveness and toxicity. The structure and antimicrobial properties of phytochemicals are also addressed. Since many of these compounds are currently available as unregulated botanical preparations and their use by the public is increasing rapidly, clinicians need to consider the consequences of patients self-medicating with these preparations.