In vitro antiprotozoal activity of extract and compounds from the stem bark of Combretum molle

A comprehensive review of antimalarial medicinal plants used by Tanzanians

CONTEXT

Tanzania has rich medicinal plant (MP) resources, and most rural inhabitants rely on traditional healing practices for their primary healthcare needs. However, available research evidence on antimalarial MPs is highly fragmented in the country.

OBJECTIVE

This systematic review compiles ethnomedicinal research evidence on MPs used by Tanzanians as antimalarials.

MATERIALS AND METHODS

A systematic web search was conducted using various electronic databases and grey materials to gather relevant information on antimalarial MPs utilized by Tanzanians. The review was per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The data were collected from 25 articles, and MS Excel software was used to analyse relevant ethnobotanical information using descriptive statistics.

RESULTS

A total of 227 MPs belonging to 67 botanical families and 180 genera were identified. Fabaceae (15.9%) is the most frequently utilized family. The ethnobotanical recipes analysis indicated leaves (40%) and trees (44%) are the preferred MPs part and life form, respectively. Decoctions (67%) are the dominant preparation method of remedies. Of the recorded MPs, 25.9% have been scientifically investigated for antimalarial activities with positive results. However, 74.1% of MPs have no scientific records on antimalarial activities, but they could be potential sources of remedies.

CONCLUSIONS

The study discloses a wealth of antimalarial MPs possessed by Tanzanians and suggests a need for research to authenticate the healing potential of antimalarial compounds from the unstudied MPs. Additionally, it indicates that some of the presented MPs are potential sources for developing safe, effective and affordable antimalarial drugs.

Invitro antibacterial activity of bark, leaf and root extracts of combretum molle plant against streptococcus equi isolated from clinical cases of strangles in donkeys and horses

BACKGROUND

Effective therapy for many infections is becoming difficult due to the evolutionary development of drug resistance, and hence, the development of alternative treatment options mainly from herbs is crucial. The objective of this study was to investigate the antibacterial effects of ethanol extracts of stem bark, leaves and roots of Combretum molle against Streptococcus equi isolated from clinical cases of strangles using in vitro tests.

METHODS

Plant extraction was performed using a maceration technique with 80% ethanol. The mean zone of inhibition was determined using the agar well diffusion method. Six serial dilutions with different concentrations (10%, 5%, 2.5%, 1.25%, 0.625% and 0.3125%) of each plant extract were prepared using dimethyl sulfoxide (DMSO). A modified agar microdilution method was used to determine the minimum inhibitory concentration (MICs) of the extracts.

RESULTS

The results revealed that all plant extracts showed significant antibacterial activity. The root extract showed the best antibacterial effect compared to the others at all concentrations, with MZI values of 27.5, 23.225, 20.5, 17.9, 15.65 and 12.25 for the respective concentrations mentioned above and an MIC of 250 µg/ml. It was followed by the stem bark extract, which had MZI values of 24.67, 22.35, 18.225, 16.175, 11.125 and 8.2 millimeters and an MIC of 375 µg/ml. The leaf extract also had significant activity, with MZI values of 20.175, 18.25, 15.7, 13.125, 9.4 and 6.75 in millimeters and an MIC of 500 µg/ml. There was a direct relationship between the concentrations of the plant extracts and the level of inhibition.

CONCLUSION

The test plant extracts were compared with the conventional antibiotic penicillin G, and the results indicated that the parts of the test plant have significant antibacterial activity, which may support traditional claims and could be candidates for alternative drug discoveries.

Antioxidant and Antibacterial Activities of the Leaf and Stem Extracts of Combretum molle (R. Br. ex G. Don.) Engl. & Diels

Medicinal plants offer reasonable and accessible alternatives to synthetic drugs and are often devoid of the adverse side effects, toxicity, and pathogenic resistance associated with synthetic medicine. Combretum molle has been utilized in African traditional medicinal practices and purportedly contains bioactive compounds with medicinally beneficial effects. This study investigated the hexane, chloroform, and methanol leaf and stem extracts for their antioxidant properties using the 2,2'-diphenyl-1-picrylhydrazyl radical scavenging and ferric-reducing antioxidant power assays. The study additionally analyzed the methanol extracts for their antibacterial activity against Gram-negative Escherichia coli (ATCC 25922) and Gram-positive Staphylococcus aureus (ATCC 25923) bacteria using agar well diffusion. Relative to the scavenging activity of the ascorbic acid control (79.15 ± 0.63% at 15 µg/mL to 94.61 ± 0.12% at 240 µg/mL), the plant's radical scavenging activities were exceptionally high in the methanolic leaf and stem extracts (p < 0.05), ranging from 94.58 ± 1.10% at 15 µg/mL to 99.22 ± 0.30% at 240 µg/mL and 91.57 ± 1.71% at 15 µg/mL to 99.60 ± 0.20% at 240 µg/mL, respectively, suggesting a strong capacity to donate hydrogen ions. High scavenging activities were additionally observed in the chloroform stem (78.68 ± 1.18% at 15 µg/mL to 98.14 ± 1.22% at 240 µg/mL) and hexane leaf (72.12 ± 4.38% at 15 µg/mL to 89.87 ± 1.50% at 240 µg/mL) extracts (p < 0.05). All extracts exhibited poor ferric-reducing abilities in relation to the gallic acid control (100 ± 0.00%) at all concentrations (p < 0.05). The leaf and stem extracts exhibited broad-spectrum antibiotic capabilities against both tested strains, with significant activity at higher concentrations (p < 0.05). Overall, both the leaf and stem extracts of C. molle exhibited similar antioxidant and antibacterial activities. These findings warrant further pharmacological research on C. molle for potential drug development.

Phytochemical Composition of Combretum molle (R. Br. ex G. Don.) Engl. & Diels Leaf and Stem Extracts

The demand for medicinal plants is on a rise due to their affordability, accessibility and relatively non-toxic nature. Combretum molle (Combretaceae) is used in African traditional medicine to treat a number of diseases. This study aimed to screen the phytochemical composition of the hexane, chloroform and methanol extracts of C. molle leaves and stems using qualitative phytochemical screening. Additionally, the study aimed to identify the functional phytochemical groups, determine the elemental composition and provide a fluorescence characterization of the powdered leaves and stems by performing Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray (EDX) microanalyses and fluorescence microscopy. Phytochemical screening revealed the presence of alkaloids, flavonoids, phenolic compounds, polyphenols, terpenoids, tannins, coumarins, saponins, phytosterols, gums, mucilage, carbohydrates, amino acids and proteins within all leaf and stem extracts. Lipids and fixed oils were additionally present within the methanol extracts. FTIR demonstrated significant peaks in absorption frequency in the leaf at wavelengths of 3283.18, 2917.81, 1617.72, 1318.83, 1233.97, 1032.32 and 521.38 cm^-1, and in the stem at 3318.91, 1619.25, 1317.13, 1032.68, 780.86 and 516.39 cm^-1. These corresponded to the functional groups of chemical compounds including alcohols, phenols, primary amines, alkyl halides, alkanes and alkyl aryl ethers, corroborating the presence of the detected phytochemicals within the plant. EDX microanalyses showed the elemental composition of the powdered leaves (68.44% C, 26.72% O, 1.87% Ca, 0.96% Cl, 0.93% Mg, 0.71% K, 0.13% Na, 0.12 % Mn and 0.10% Rb) and stems (54.92% C, 42.86% O, 1.7% Ca, 0.43% Mg and 0.09% Mn). Fluorescence microscopy provided a characteristic evaluation of the plant in its powdered form and revealed distinct colour changes in the material when treated with various reagents and viewed under ultraviolet light. In conclusion, the phytochemical constituents of the leaves and stems of C. molle confirm the suitability of this species for use in traditional medicine. The findings from this study suggest the need to validate the use of C. molle in the development of modern medicines.

Development of an Analytical Workflow to Support the Establishment of Monographs in African Pharmacopoeias - Combretum mucronatum Leaves as Example

Herbal medicines are invaluable in African medicine, but quality and safety are not documented in many cases. Besides controlled farming, validated quality control methods are needed to ensure identity, purity, and content. Analytical specifications within modern monographs are needed for consistent batch quality. Combretum mucronatum leaves are widely used in West Africa, but state-of-the-art quality control methods and specifications are non-existent. The aim of the following study was the development of ICH-validated chromatographic protocols for identity, purity, content assay, and analytical specifications for consideration into pharmacopoeial monographs. UPLC-ESI-Q-TOF-MS/MS was used for untargeted phytochemical information on composition. Optimisation of extraction was based on phytochemical profiling. HPTLC was used for differentiation of C. mucronatum from other Combretum species and UPLC for simultaneous determination of 7 marker compounds. C. mucronatum batch analyses (n = 49) investigated the influence of harvest time and geographical origin. Pesticides screening from a 349-compound panel were carried out. 30 compounds, identified by LC-MS, were used for characterization of the plant material. Orietin, isoorientin, vitexin and isovitexin were used as specific marker compounds for qualitative and quantitative HPTLC purposes, while UPLC quantified additionally epicatechin, procyanidins B2 and C1. Influence of harvest time and geographic origin on the content of marker compounds was observed. Differences in the metabolite profiles of C. mucronatum compared to related Combretum species were established for quality control purposes. Contamination with high amoounts of chlorpyrifos, and folpet (sum of folpet and phtalimide, expressed as folpet) were also observed.The study provides analytical protocols, analytical specifications and a drafted monograph for consideration for African pharmacopoeias, and reveals potential challenges in the quality of C. mucronatum.

Evaluation of the Anti-Malarial Activity of the Crude Root Extract and Solvent Fraction of Sesamum indicum (Fabaceae)

Background

A major cumbersome factor in malaria control measure is the new coming antimalarial drug resistance strains. The increase of resistance to the available marketed antimalarial agents dictates the scientific community to search new alternative antimalarial agent from traditional plants. Therefore, our study assesses the antimalarial activity of the crude root extract and solvent fraction of Sesamum indicum in mice.

Methods

The roots of Sesamum indicum were extracted by 80% methanol and fractionated using three solvents with different polarities. The in vivo antimalarial activity was assessed at 200 mg/kg, 400 mg/kg, and 600 mg/kg of the root crude extract and solvent fraction using the 4-day suppressive test. Similarly, the n- butanol fraction extract, which showed better suppression potential in 4-day suppressive test from other fractions was also evaluated in the curative model to assess its curative potential. The % parasitemia suppression, mean survival time, body weight change, rectal temperature change, and packed cell volume change were also evaluated in both models.

Results

Our finding revealed that the crude extract and solvent fraction treated groups had a statistical significant parasitemia suppression and mean survival time improvement as compared to the negative control (p<0.001) in both models in a dose-dependent fashion. The higher dose n-butanol fraction treated group (600mg/kg) showed the highest suppression effect and mean survival time prolongation in both tests from the other two fractions. However, the lowest suppressive effect was observed in 200 mg/kg aqueous fraction extract-treated groups in the 4-day suppressive test.

Conclusion

The crude root extract and solvent fractions of Sesamum indicum possessed a dose dependent antimalarial activity and a significant change in other parameters in both models that strengthen the traditional claim.

Cytotoxicity, Antimicrobial, Antioxidant, Anthelmintic, and Anti-Inflammatory Activities and FTIR Analysis of Combretum nioroense Stem Bark

Combretum nioroense is widely used in the folkloric treatment of a variety of bacterial and helminthic infections. The decoction of its leaves is traditionally fed to newborn babies in some rural parts of Ghana. The study focused on identifying the prime components of petroleum ether and ethanolic extracts of the stem bark using standard phytochemical screening protocols and chromatographic and spectroscopic techniques. The activities (cytotoxicity, antimicrobial, antioxidant, anthelmintic, and anti-inflammatory) of the extracts of C. nioroense were also investigated. Preliminary phytochemical analysis of the extracts revealed the presence of glycosides, saponins, phenols, coumarins, alkaloids, flavonoids, tannins, steroids, phytosterols, flavanols, terpenoids, and cardiac glycosides. The action of the extracts of C. nioroense on Milsonia ghanensis worms was concentration-dependent, with the least concentration (0.75 mg/mL) paralyzing and killing M. ghanensis after the maximal exposure time. The IC50 values for petroleum ether and ethanol extracts in the DPPH assay were >100.0 and 27.940 ± 1.005 μg/mL and those of the H2O2 assay were 400.900 ± 3.400 and 322.500 ± 1.005 μg/mL, respectively. The total antioxidant capacities (TACs) for petroleum ether and ethanol extracts were 47.197 ± 0.533 and 57.968 ± 0.560 gAAE/100 g, respectively. The IC50 value for ethanol extract in the cytotoxicity studies was 115.4 ± 1.332 μg/mL. The MICs of the extracts against the test organisms were within the range of 0.0122–25.0 mg/mL. The extracts (petroleum ether and ethanol) showed a concentration-dependent increase in anti-inflammatory activity with IC50 values of 31.254 ± 0.359 and 24.402 ± 0.569 μg/mL, respectively. Chromatographic separations of the ethanol extract gave three fractions. FTIR analysis of the extracts and purified fractions revealed the presence of functional groups, confirming the presence of the phytochemicals identified in the screening test. The results indicate that both extracts of C. nioroense exhibit cytotoxicity, antimicrobial, antioxidant, anthelmintic, and anti-inflammatory activities, thereby proving the folkloric use to treat ailments caused by worms and microorganisms.

In Vivo Anti-Malarial Activity of the Aqueous Root Extract of Euclea divinorum Hiern (Ebenaceae) against Plasmodium berghei ANKA

Background

Drug resistance is a universal challenge to malaria control measures. As a result, the development and discovery of new chemotherapeutic agents from medicinal plants having anti-malarial traditional claims are very important. This work, therefore, attempted to evaluate the anti-malarial activity of the aqueous root extract of E. divinorum using a rodent model of malaria.

Methods

The roots of E. divinorum were extracted by hot decoction using distilled water. Anti-malarial activity of various doses (100 mg/kg, 200 mg/kg, and 600 mg/kg) of the root aqueous extract was evaluated using the 4-day suppressive test as well as curative and repository tests. Parasitemia, rectal temperature, body weight, PCV, and MST were also determined.

Results

The finding showed that there were a dose-related significant parasitemia chemo-suppression and increment in survival time as compared to the negative control (p < 0.001) in all tests. The chemo-suppression effect was higher at 400 mg/kg extract-treated groups in the 4-day suppressive test followed by the curative test. The lowest chemo-prophylaxis effect was observed in 100 mg/kg extract-treated groups in the repository test. Regarding the other parameters, the extract prevented weight loss, temperature drop, and hemolysis in all models but not in a consistent manner.

Conclusion

The current study showed that the aqueous root extract of E. divinorum possessed a varying degree of anti-malarial activity in all three tests, with greater parasitemia suppression observed in the 4-day suppressive test. The extract produced higher parasitemia chemo-suppression and longer survival time in early infections followed by established and then residual infection.

A Comparative Analysis of Punicalagin Interaction with PDIA1 and PDIA3 by Biochemical and Computational Approaches

In a previous work, it was shown that punicalagin, an active ingredient of pomegranate, is able to bind to PDIA3 and inhibit its disulfide reductase activity. Here we provide evidence that punicalagin can also bind to PDIA1, the main expressed form of protein disulfide isomerase (PDI). In this comparative study, the affinity and the effect of punicalagin binding on each protein were evaluated, and a computational approach was used to identify putative binding sites. Punicalagin binds to either PDIA1 or PDIA3 with a similar affinity, but the inhibition efficacy on protein reductase activity is higher for PDIA3. Additionally, punicalagin differently affects the thermal denaturation profile of both proteins. Molecular docking and molecular dynamics simulations led to propose a punicalagin binding mode on PDIA1 and PDIA3, identifying the binding sites at the redox domains a’ in two different pockets, suggesting different effects of punicalagin on proteins’ structure. This study provides insights to develop punicalagin-based ligands, to set up a rational design for PDIA3 selective inhibitors, and to dissect the molecular determinant to modulate the protein activity.

Hydrolyzable tannins (ellagitannins), flavonoids, pentacyclic triterpenes and their glycosides in antimycobacterial extracts of the ethnopharmacologically selected Sudanese medicinal plant Combretum hartmannianum Schweinf

In Sudanese traditional medicine, decoctions, macerations, and tonics of the stem and root of Combretum hartmannianum are used for the treatment of persistent cough, a symptom that could be related to tuberculosis (TB). To verify these traditional uses, extracts from the stem wood, stem bark, and roots of C. hartmannianum were screened for their growth inhibitory effects against Mycobacterium smegmatis ATCC 14468. Methanol Soxhlet and ethyl acetate extracts of the root gave the strongest effects (MIC 312.5 and 625 µg/ml, respectively). HPLC-UV/DAD and UHPLC/QTOF-MS analysis of the ethyl acetate extract of the root led to the detection of 54 compounds, of which most were polyphenols and many characterized for the first time in C. hartmannianum. Among the major compounds were terflavin B and its two isomers, castalagin, corilagin, tellimagrandin I and its derivative, (S)-flavogallonic acid dilactone, punicalagin, and methyl-ellagic acid xylopyranoside. In addition, di-, tri- and tetra-galloyl glucose, combregenin, terminolic acid, cordifoliside D, luteolin, and quercetin-3-O-galactoside-7-O-rhamnoside-(2→1)-O-β-D-arabinopyranoside were characterized. Luteolin gave better growth inhibition against M. smegmatis (MIC 250 µg/ml) than corilagin, ellagic acid, and gallic acid (MIC 500-1000 µg/ml). Our study justifies the use of C. hartmannianum in Sudanese folk medicine against prolonged cough that could be related to TB infection. This study demonstrates that C. hartmannianum should be explored further for new anti-TB drug scaffolds and antibiotic adjuvants.

Harnessing polyphenol power by targeting eNOS for vascular diseases

Vascular diseases arise due to vascular endothelium dysfunction in response to several pro-inflammatory stimuli and invading pathogens. Thickening of the vessel wall, formation of atherosclerotic plaques consisting of proliferating smooth muscle cells, macrophages and lymphocytes are the major consequences of impaired endothelium resulting in atherosclerosis, hypercholesterolemia, hypertension, type 2 diabetes mellitus, chronic renal failure and many others. Decreased nitric oxide (NO) bioavailability was found to be associated with anomalous endothelial function because of either its reduced production level by endothelial NO synthase (eNOS) which synthesize this potent endogenous vasodilator from L-arginine or its enhanced breakdown due to severe oxidative stress and eNOS uncoupling. Polyphenols are a group of bioactive compounds having more than 7000 chemical entities present in different cereals, fruits and vegetables. These natural compounds possess many OH groups which are largely responsible for their strong antioxidative, anti-inflammatory antithrombotic and anti-hypersensitive properties. Several flavonoid-derived polyphenols like flavones, isoflavones, flavanones, flavonols and anthocyanidins and non-flavonoid polyphenols like tannins, curcumins and resveratrol have attracted scientific interest for their beneficial effects in preventing endothelial dysfunction. This article will focus on in vitro as well as in vivo and clinical studies evidences of the polyphenols with eNOS modulating activity against vascular disease condition while their molecular mechanism will also be discussed.

In vitro Antileishmanial, Antitrypanosomal, and Anti-inflammatory-like Activity of Terminalia mollis Root Bark

This study aims at determining the in vitro antitrypanosomal, antileishmanial, antioxidant, and anti-inflammatory-like activities of Terminalia mollis root crude extracts. The antitrypanosomal and antileishmanial activities on Trypanosoma brucei brucei (strain 427) and promastigotes of Leishmania mexicana mexicana (MHOM/BZ/84/BEL46) were evaluated in vitro. The methanolic root bark extract and standards were profiled by HPLC-PDA, and the majority of compounds identified using literature data. The in vitro antioxidant and anti-inflammatory-like activities were determined by evaluating the effect of crude extracts on reactive oxygen species produced by phorbol 12-myristate 13-acetate-stimulated equine neutrophils using lucigenin-enhanced chemiluminescence and on purified equine myeloperoxidase activity measured by specific immunological extraction followed by enzymatic detection. The methanolic, aqueous crude extract, and aqueous crude extract free of tannins exhibited good growth inhibition on Trypanosoma brucei brucei (IC₅₀ 3.72, 6.05, and 4.45 µg/mL respectively) but were inactive against Leishmania mexicana mexicana (IC₅₀ > 100 µg/mL). Suramin (IC₅₀ 0.11 µg/mL) and amphotericin (IC₅₀ 0.11 µg/mL) were used as standard respectively for the antitrypanosomal and antileishmanial activity. Very interesting antioxidant and anti-inflammatory-like activities were observed with 50% hydroethanolic, aqueous crude extracts, and aqueous crude extract free of tannins as well as with pure punicalagin, gallic, and ellagic acid (IC₅₀ 0.38 - 10.51 µg/mL for 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid), chemiluminescence, and specific immunological extraction followed by enzymatic detection assays. The study results support traditional medicinal use of the plant for the treatment of parasitical disorders and revealed for the first time the antitrypanosomal potential, anti-inflammatory-like, and antioxidant activity of Terminalia mollis root.

In Vitro Studies on Antioxidant and Anti-Parasitic Activities of Compounds Isolated from Rauvolfia caffra Sond

As part of an ongoing study of natural products from local medicinal plants, the methanol extract of stem bark of Rauvolfia caffra Sond was investigated for biological activity. Column chromatography and preparative thin-layer chromatography were used to isolate lupeol (1), raucaffricine (2), N-methylsarpagine (3), and spegatrine (4). The crude extract, fractions and isolated compounds were tested for anti-oxidant, antitrypanosomal and anti-proliferation activities. Two fractions displayed high DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and reducing power with IC₅₀ (The half maximal inhibitory concentration) and IC_0.5 values of 0.022 ± 0.003 mg/mL and 0.036 ± 0.007 mg/mL, and 0.518 ± 0.044 mg/mL and 1.076 ± 0.136 mg/mL, respectively. Spegatrine (4) was identified as the main antioxidant compound in R. caffra with IC₅₀ and IC_0.5 values of 0.119 ± 0.067 mg/mL and 0.712 ± 0 mg/mL, respectively. One fraction displayed high antitrypanosomal activity with an IC₅₀ value of 18.50 μg/mL. However, the major constituent of this fraction, raucaffricine (2), was not active. The crude extract, fractions and pure compounds did not display any cytotoxic effect at a concentration of 50 μg/mL against HeLa cells. This study shows directions for further in vitro studies on the antioxidant and antitrypanosomal activities of Rauvolfia caffra Sond.

Antimalarial Plants Used across Kenyan Communities

Malaria is one of the serious health problems in Africa, Asia, and Latin America. Its treatment has been met with chronic failure due to pathogenic resistance to the currently available drugs. This review attempts to compile phytotherapeutical information on antimalarial plants in Kenya based on electronic data. A comprehensive web search was conducted in multidisciplinary databases, and a total of 286 plant species from 75 families, distributed among 192 genera, were retrieved. Globally, about 139 (48.6%) of the species have been investigated for antiplasmodial (18%) or antimalarial activities (97.1%) with promising results. However, there is no record on the antimalarial activity of about 51.4% of the species used although they could be potential sources of antimalarial remedies. Analysis of ethnomedicinal recipes indicated that mainly leaves (27.7%) and roots (19.4%) of shrubs (33.2%), trees (30.1%), and herbs (29.7%) are used for preparation of antimalarial decoctions (70.5%) and infusions (5.4%) in Kenya. The study highlighted a rich diversity of indigenous antimalarial plants with equally divergent herbal remedy preparation and use pattern. Further research is required to validate the therapeutic potential of antimalarial compounds from the unstudied claimed species. Although some species were investigated for their antimalarial efficacies, their toxicity and safety aspects need to be further investigated.

Evaluation of Antimalarial Activity of the 80% Methanolic Stem Bark Extract of Combretum molle Against Plasmodium berghei in Mice

BACKGROUND

People are dependent on the traditional use of medicinal plants for the treatment of malaria without scientific validations. Therefore, this study aimed to evaluate the antimalarial activity of methanolic stem bark extract of Combretum molle in mice.

METHODS

After being infected with Plasmodium berghei, the mice were randomly divided into 5 groups (n = 5). In all cases, group I mice were treated as negative control and received 3% Tween 80; group II mice were treated with 25 mg/kg chloroquine; and groups III, IV, and V mice were treated with 100 mg/kg, 200 mg/kg, and 400 mg/kg of crude extract, respectively. Data were analyzed using one-way analysis of variance followed by Tukey's post hoc analysis.

RESULTS

In the chemosuppressive test, the parasitic suppression effect of the crude extract was found to be significant (P < 0.05) as compared with the negative control. In the curative experiment, the average parasitic level of those mice treated by the 3 doses of the crude extract was significantly suppressed at days 5, 6, and 7 of treatment (P < 0.001). Besides, the crude extract had been found to have a chemoprophylactic role as it inhibited the parasite level significantly relative to the negative control (P < 0.001). Moreover, the crude extract had preventive effects on packed cell volume reduction in the 3 tests (P < 0.001).

CONCLUSIONS

The findings of the present study has supported the folklore use of the leaves of Combretum molle in the treatment of malaria. Therefore, further fractionation and characterization of the crude extract is necessary to identify the responsible lead compound(s) responsible for antiplasmodial activity.

Antimalarial herbal remedies of Bukavu and Uvira areas in DR Congo: An ethnobotanical survey

ETHNOPHARMACOLOGICAL RELEVANCE

The main objective of the present study was to collect and gather information on herbal remedies traditionally used for the treatment of malaria in Bukavu and Uvira, two towns of the South Kivu province in DRC.

MATERIAL AND METHODS

Direct interview with field enquiries allowed collecting ethnobotanical data; for each plant, a specimen was harvested in the presence of the interviewed traditional healers (THs). The recorded information included vernacular names, morphological parts of plants, methods of preparation and administration of remedies, dosage and treatment duration. Plants were identified with the help of botanists in the herbaria of INERA/KIPOPO (DRC) and the Botanic Garden of Meise (Belgium), where voucher specimens have been deposited. The results were analysed and discussed in the context of previous published data.

RESULTS

Interviewees cited 45 plant species belonging to 41 genera and 21 families used for the treatment of malaria. These plants are used in the preparation of 52 recipes, including 25 multi-herbal recipes and 27 mono-herbal recipes. Apart of Artemisia annua L. (Asteraceae; % Citation frequency = 34%) and Carica papaya L. (Caricaceae; % Citation frequency = 34%), the study has highlighted that the most represented families are Asteraceae with 12 species (26%), followed by Fabaceae with 7 species (16%) and Rubiaceae with 4 species (9%). For a majority of plants, herbal medicines are prepared from the leaves in the form of decoction and administered by oral route.

CONCLUSION

Literature data indicate that part of cited species are already known (38%) and/or studied (30%) for antimalarial properties, which gives credit to the experience of Bukavu and Uvira interviewees and some level of confidence on collected information. The highly cited plants should be investigated in details for the isolation and identification of active ingredients, a contribution to the discovery of new possibly effective antimalarials.

Investigation of wound healing activity of Lafoensia pacari (Lythraceae) leaves extract cultivated in Goiás state, Brazil

Abstract Lafoensia pacari has been used in traditional folk medicine in Brazilian Cerrado to treat wounds. It is important to develop studies that can clarify how the biological activity of L. pacari occurs. The aim of this study was to evaluate the healing activity of L. pacari leaves extract in an animal model. The extract was prepared from plants cultivated in Goiania-GO, Brazil. The healing activity was assayed using cutaneous wound model in rats, and macroscopic, morphometric and histological analysis of wounds were also conducted. The presence of hydrolysable tannins was detected in thin layer chromatography and in high performance liquid chromatography analysis, may be suggested the presence of ellagitannins. In the evaluation of cutaneous wounds in rats it was possible to observe that the treatment with 10% (w/v) L. pacari extract provided a reduction in the time of cutaneous wound healing, with a significant increase in variables involved in healing, such as the number of blood vessels and collagen production. Therefore, this study shows that L. pacari wound healing potential may be related to the presence of ellagitannins and corroborates to ethnopharmacological reports regarding this plant.

Anti-inflammatory and phytochemical evaluation of Combretum aculeatum Vent growing in Sudan

ETHNOPHARMACOLOGICAL RELEVANCE

Combretum aculeatum Vent was traditionally used in Sudan, Eretria and Ethiopia as anti-inflammatory in case of skin inflammation, catarrh, wounds, scorpion stings and snake bites. Nevertheless, there is no scientific information regarding this activity.

AIM OF STUDY

The present study aimed to evaluate the phytochemical constituents and the scientific basis for the traditional use of Combretum aculeatum Vent through studying its anti-inflammatory properties for the first time to illustrate the putative mechanisms behind this bioactivity.

MATERIALS AND METHODS

the ethanolic extract was partitioned by petroleum ether, methylene chloride, ethyl acetate, and n-butanol saturated with water. The petroleum ether fraction was saponified and the saponifiable and unsaponifiable fractions were analyzed on GC/MS. The different fractions were subjected to phytochemical investigation to isolate pure compounds. In-vivo anti-inflammatory activity of the ethanolic extract was evaluated using carrageenan induced rat paws edema method at doses of 200, 400 and 600 mg/kg and proved based on histopathological and biochemical parameters.

RESULTS

Five known compounds were isolated for the first time from the aerial parts of Combretum aculeatum Vent: quercetin, vitexin, isorhamnetin 3-O-β-glucoside, isovitexin and rutin, in addition to two previously isolated ones: β-sitosterol and its glucoside. The ethanolic extract evidenced in-vivo anti-inflammatory activity by oral intake of 400 mg/kg of the ethanolic extract significantly (P ≥ 0.05) decreased the paw edema (only 32±1.9% increase in paw weight after 4 h) compared to indomethacin (28.6±2.5%). Moreover, it significantly suppressed the serum malondialdehyde (MDA) and nitric oxide (NO) and increased the GSH to be 11.76±0.85, 5.13±0.62 μmol/mL and 5.66±0.28 μM/mL, respectively. It diminished the serum cytokines TNF-α, IL-6 and IL-1β levels to be 39.1±1.2, 32.6±1.1 and 37.5±1.2 pg/mL, respectively. Results are accompanied by histopathological examination.

CONCLUSION

Overall, the results herein presented significant anti-inflammatory properties traditionally ascribed to Combretum aculeatum Vent. Moreover, the biochemical mechanisms associated to this action were highlighted, introducing new prospects for the development of effective anti-inflammatory herbal medicinal products.

Exploring Antimalarial Herbal Plants across Communities in Uganda Based on Electronic Data

Malaria is one of the most rampant diseases today not only in Uganda but also throughout Africa. Hence, it needs very close attention as it can be severe, causing many deaths, especially due to the rising prevalence of pathogenic resistance to current antimalarial drugs. The majority of the Ugandan population relies on traditional herbal medicines for various health issues. Thus, herein, we review various plant resources used to treat malaria across communities in Uganda so as to provide comprehensive and valuable ethnobotanical data about these plants. Approximately 182 plant species from 63 different plant families are used for malaria treatment across several communities in Uganda, of which 112 plant species have been investigated for antimalarial activities and 96% of the plant species showing positive results. Some plants showed very strong antimalarial activities and could be investigated further for the identification and validation of potentially therapeutic antimalarial compounds. There is no record of an investigation of antimalarial activity for approximately 39% of the plant species used for malaria treatment, yet these plants could be potential sources for potent antimalarial remedies. Thus, the review provides guidance for areas of further research on potential plant resources that could be sources of compounds with therapeutic properties for the treatment of malaria. Some of the plants were investigated for antimalarial activities, and their efficacy, toxicity, and safety aspects still need to be studied.

Phytochemical Screening and In Vivo Antimalarial Activity of Two Traditionally Used Medicinal Plants of Afar Region, Ethiopia, against Plasmodium berghei in Swiss Albino Mice

The objective of the present study was to investigate phytochemical components, antiplasmodial activity (in vivo) and evaluate the toxicity of two local medicinal plants, namely, Salvadora persica L. and Balanites rotundifolia (Van Tiegh.) used in Afar ethnomedicine for the treatment of malaria. In this study, phytochemical screening has been done using standard methods and the existence of antiplasmodial compounds was detected in these plant extracts. Four-day Peter's test was used to determine parasite inhibition, PCV was determined by Wintrob's method, and effects against loss of body weight and improvements on survival time were determined. LD50s of the crude extracts have been also done. Acute toxicity studies of the extracts were carried out in Swiss albino mice prior to antimalarial activity test. All extracts revealed no obvious acute toxicities on mice up to the highest (5000mg/kg) dose given. The crude extract was estimated to have oral median lethal dose higher than 5,000 mg/kg. With the 4-day suppressive test, both plant extracts demonstrated dose-dependent significant reduction in parasitemia level at all test doses compared to the negative control: in the extract of B. rotundifolia 500 mg/kg extract (60.59±3.25%), 350 mg/kg extract (48.1±1.4), and 200 mg/kg extract (41.33±1.1%) were found. And in case of S. Persica 500 mg/kg extract (50.6±4.01%), 350 mg/kg extract (35.85±0.89), and 200 mg/kg extract (27.69±1.14%) were found. The results of this study provide support for the traditional therapeutic value and the reported antimalarial activity.

Evaluation of Antimalarial Activity of the Leaf Latex and TLC Isolates from Aloe megalacantha Baker in Plasmodium berghei Infected Mice

Malaria is a devastating parasitic disease which caused around 216 million cases and 445,000 deaths worldwide in 2016. This might be attributed to a wide spread of drug resistant parasites. The plant Aloe megalacantha is indigenous to Ethiopia where the sap of the leaves is traditionally used for the treatment of malaria. This study was aimed at evaluating the antimalarial effect of leaf latex and isolates obtained from Aloe megalacantha against chloroquine sensitive Plasmodium berghei ANKA strain in Swiss albino mice. Peters' 4-day suppressive test method was used to test the antimalarial activity of both leaves latex and isolates. Three isolates were obtained using thin layer chromatography and were coded as AM₁, AM₂, and AM₃ in ascending order of their retention factor. After treatment of Plasmodium berghei infected mice with leaf latex of Aloe megalacantha for four days at 100, 200, and 400 mg/kg, it shows 30.3%, 43.4%, and 56.4% suppression of the parasite growth, respectively. 32.3%, 51.3%, and 67.4% chemosuppression after treatment with AM₁, 39.8%, 50.6%, and 64.2% chemosuppression after treatment with AM₂, and 52.6%, 69.4%, and 79.6% chemosuppression after treatment with AM₃ were observed at doses of 100, 200, and 400 mg/kg/day, respectively. The observed parasite suppression of leaves latex and isolates was statistically significant (P<0.05) as compared to negative control. Moreover, both the leaves latex and isolates were also observed to prevent Plasmodium berghei induced body weight loss and hypothermia and increased the survival time of Plasmodium berghei infected mice as compared to the negative control. Hence, the present study supports the traditional claim of the plant for the treatment of malaria.

N-myristoyltransferases inhibitory activity of ellagitannins from Terminalia bentzoë (L.) L. f. subsp. bentzoë

N-myristoylation (Myr) is an eukaryotic N-terminal co- or post-translational protein modification in which the enzyme N-myristoyltransferase (NMT) transfers a fatty acid (C14:0) to the N-terminal glycine residues of several cellular key proteins. Depending on the cellular context, NMT may serve as a molecular target in anticancer or anti-infectious therapy, and drugs that inhibit this enzyme may be useful in the treatment of cancer or infectious diseases. As part of an on-going project to identify natural Homo sapiens N-myristoyltransferase 1 inhibitors (HsNMT1), two ellagitannins, punicalagin (1) and isoterchebulin (2), along with eschweilenol C (3) and ellagic acid (4) were isolated from the bark of Terminalia bentzoë (L.) L. f. subsp. bentzoë. Their structures were determined by means of spectroscopic analyses and comparison with literature data. Punicalagin (1) and isoterchebulin (2) showed significant inhibitory activity towards HsNMT1, and also against Plasmodium falciparum NMT (PfNMT) both in vitro and in cellulo, opening alternative paths for new NMT inhibitors development. This is the first report identifying natural products from a botanical source as inhibitors of HsNMT and PfNMT.

Treatment of malaria and related symptoms using traditional herbal medicine in Ethiopia

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal plants have always been an integral part of different cultures in Ethiopia in the treatment of different illnesses including malaria and related symptoms. However, due to lack of proper documentation, urbanization, drought, acculturation and deforestation, there is an increased risk of losing this traditional knowledge. Hence, the use of the indigenous knowledge should be well documented and validated for potential future use.

AIM OF THE STUDY

To gather and document information on medicinal plants which are used in the traditional treatment of malaria and related symptoms in Ethiopia.

MATERIALS AND METHODS

First, an ethnomedicinal survey of plants was conducted in 17 districts of Jimma zone, the Oromia national regional state of Ethiopia. Jimma zone is malarious and rich in natural flora. A total of 115 traditional healers were interviewed using a semi-structured questionnaire containing personal data of the respondents, and information on medicinal plants used to treat malaria and related symptoms. In addition, a literature search using Medline/PubMed, Google Scholar, ScienceDirect and HINARI was conducted on the indigenous use, in-vitro/in-vivo anti-malarial activity reports, and the chemical characterization of medicinal plants of Ethiopia used against malaria.

RESULTS

From ethnomedicinal survey, a total of 28 species of plants used in the traditional treatment of malaria and related symptoms in Jimma Zone were collected, identified and documented. In addition, the literature search revealed that 124 medicinal plant species were reported to be traditionally used in the treatment of malaria in Ethiopia. From both ethnomedicinal survey and the literature search, Asteraceae and Fabaceae were the most represented families and Allium sativum L., Carica papaya L., Vernonia amygdalina Del., Lepidium sativum L. and Croton macrostachyus Del. were the most frequently reported plant species for their anti-malarial use. The dominant plant parts used in the preparation of remedies were leaves. About 54% of the medicinal plants documented in the survey have been reported as an anti-malarial plant in the literature search. Furthermore, the in-vitro and in-vivo anti-plasmodial activity reports of extracts from some of plant species were found to support the traditional claim of the documented plants. Moreover, literatures indicate that several secondary metabolites isolated from certain plant species that are traditionally used for the treatment of malaria and related symptoms in Ethiopia demonstrate strong anti-plasmodial activity.

CONCLUSIONS

The result of the current study showed that traditional knowledge is still playing an important role in the management of malaria and related symptoms in Ethiopia. Allium sativum L., Carica papaya L., Vernonia amygdalina Del., and Lepidium sativum L. are the most commonly reported species as anti-malarial plants and the traditional claim of some species was supported by known anti-plasmodial activity and bioactivity reports. The finding of this study is important in the rational prioritization of plant species which are potentially used for investigating new compounds, which could be efficacious for malaria treatment.

Landolphia owariensis leaf extracts reduce parasitemia in Plasmodium berghei-infected mice

Context Landolphia owariensis P. Beauv. (Apocyanaceae) leaf is used in southeast Nigeria to treat malaria. Objective This study evaluated the antiplasmodial activity of L. owariensis leaf extract and fractions, also the phytoconstituents were standardized and analyzed. Methods The effects of daily, oral administrations of 200, 400 and 800 mg/kg of L. owariensis leaf extract (LOE), its hexane (LOHF), ethyl acetate (LOEF) and methanol (LOMF) fractions on early, established and residual infections in Plasmodium berghei-infected albino mice were evaluated in vivo. The extract and fractions were subjected to phytochemical analysis and HPLC fingerprinting, and the acute toxicity of LOE was evaluated. Results The extract and fractions elicited 29-86, 18-95 and 75-96% significant (p < 0.001) suppression of parasitemia in early, established and residual infections, respectively. The ED50 values for suppressive activity of LOE, LOHF, LOEF and LOMF were 266.56, 514.93, 392.95 and 165.70 mg/kg, respectively. The post-day 30-survival index was 16.7-50, 16.7, 16.7-66.7 and 50-83.3% for LOE, LOHF, LOEF, and LOMF, respectively. Extract-treated mice significantly (p < 0.001) gained weight and had reduced mortality compared with negative control (untreated) mice. An oral LD50 value  >5000 mg/kg in mice was established for LOE. The LOMF showed the greatest antiplasmodial activity in all the models, suggesting that the antimalarial activity of the plant may be attributed to alkaloids, flavonoids, saponins and tannins present in the fraction. Conclusion Results demonstrate the antiplasmodial activity of L. owariensis leaf, and provide a pharmacological rationale for its ethnomedicinal use as an antimalarial agent.

Cytotoxicity of 91 Kenyan indigenous medicinal plants towards human CCRF-CEM leukemia cells

ETHNOPHARMACOLOGICAL RELEVANCE

Plants from Kenyan flora are traditionally used against many ailments, including cancer and related diseases. Cancer is characterized as a condition with complex signs and symptoms. Recently there are recommendations that ethnopharmacological usages such as immune and skin disorders, inflammatory, infectious, parasitic and viral diseases should be taken into account when selecting plants that treat cancer.

AIM

The present study was aimed at investigating the cytotoxicity of a plethora of 145 plant parts from 91 medicinal plants, most of which are used in the management of cancer and related diseases by different communities in Kenya, against CCRF-CEM leukemia cell line.

MATERIALS AND METHODS

Extracts from different plant parts (leaves, stems, stem bark, roots, root barks, aerial parts and whole herb) were obtained by cold percolation using different solvent systems, such as (1:1v/v) dichloromethane (CH2Cl2) and n-hexane (1), methanol (MeOH) and CH2Cl2 (2); neat MeOH (3), 5% H2O in MeOH (4) and with ethanol (EtOH, 5); their cytotoxicities were determined using the resazurin reduction assay against CCRF-CEM cells.

RESULTS

At a single concentration of 10μg/mL, 12 out of 145 extracts exhibited more than 50% cell inhibition. These include samples from the root bark of Erythrina sacleuxii (extracted with 50% n-hexane-CH2Cl2), the leaves of Albizia gummifera, and Strychnos usambarensis, the stem bark of Zanthoxylum gilletii, Bridelia micrantha, Croton sylvaticus, and Albizia schimperiana; the root bark of Erythrina burttii and E. sacleuxii (extracted with 50% CH2Cl2-MeOH), the stem bark of B. micrantha and Z. gilletii (extracted using 5% MeOH-H2O) and from the berries of Solanum aculeastrum (extracted with neat EtOH). The EtOH extract of the berries of S. aculeastrum and A. schimperiana stem bark extract displayed the highest cytotoxicity towards leukemia CCRF-CEM cells, with IC50 values of 1.36 and 2.97µg/mL, respectively. Other extracts having good activities included the extracts of the stem barks of Z. gilletii and B. micrantha and leaves of S. usambarensis with IC50 values of 9.04, 9.43 and 11.09µg/mL, respectively.

CONCLUSIONS

The results of this study provided information related to the possible use of some Kenyam medicinal plants, and mostly S. aculeastrum, A. schimperiana, C. sylvaticus, Z. gilletii, B. micrantha and S. usambarensis in the treatment of leukemia. The reported data helped to authenticate the claimed traditional use of these plants. However, most plants are used in combination as traditional herbal concoctions. Hence, the cytotoxicity of corresponding plant combinations should be tested in vitro to authenticate the traditional medical practitioners actual practices.

Plants as antimalarial agents in Sub-Saharan Africa

Although the burden of malaria is decreasing, parasite resistance to current antimalarial drugs and resistance to insecticides by vector mosquitoes threaten the prospects of malaria elimination in endemic areas. Corollary, there is a scientific departure to discover new antimalarial agents from nature. Because the two antimalarial drugs quinine and artemisinin were discovered through improved understanding of the indigenous knowledge of plants, bioprospecting Sub-Saharan Africa's enormous plant biodiversity may be a source of new and better drugs to treat malaria. This review analyses the medicinal plants used to manage malaria in Sub-Saharan Africa. Chemical compounds with antiplasmodial activity are described. In the Sub-Saharan African countries cited in this review, hundreds of plants are used as antimalarial remedies. While the number of plant species is not exhaustive, plants used in more than one country probably indicate better antimalarial efficacy and safety. The antiplasmodial data suggest an opportunity for inventing new antimalarial drugs from Sub-Saharan-African flora.

The effect of (-)-epigallocatechin 3-O--gallate in vitro and in vivo in Leishmania braziliensis: involvement of reactive oxygen species as a mechanism of action

BACKGROUND

Leishmaniasis is a parasitic disease associated with extensive mortality and morbidity. The treatment for leishmaniasis is currently based on pentavalent antimonials and amphotericin B; however, these drugs result in numerous adverse side effects. Natural compounds have been used as novel treatments for parasitic diseases. In this paper, we evaluated the effect of (-)-epigallocatechin 3-O-gallate (EGCG) on Leishmania braziliensis in vitro and in vivo and described the mechanism of EGCG action against L. braziliensis promastigotes and intracellular amastigotes.

METHODOLOGY/PRINCIPAL FINDING

In vitro activity and reactive oxygen species (ROS) measurements were determined during the promastigote and intracellular amastigote life stages. The effect of EGCG on mitochondrial membrane potential (ΔΨm) was assayed using JC-1, and intracellular ATP concentrations were measured using a luciferin-luciferase system. The in vivo experiments were performed in infected BALB/c mice orally treated with EGCG. EGCG reduced promastigote viability and the infection index in a time- and dose-dependent manner, with IC50 values of 278.8 µM and 3.4 µM, respectively, at 72 h and a selectivity index of 149.5. In addition, EGCG induced ROS production in the promastigote and intracellular amastigote, and the effects were reversed by polyethylene glycol (PEG)-catalase. Additionally, EGCG reduced ΔΨm, thereby decreasing intracellular ATP concentrations in promastigotes. Furthermore, EGCG treatment was also effective in vivo, demonstrating oral bioavailability and reduced parasitic loads without altering serological toxicity markers.

CONCLUSIONS/SIGNIFICANCE

In conclusion, our study demonstrates the leishmanicidal effects of EGCG against the two forms of L. braziliensis, the promastigote and amastigote. In addition, EGCG promotes ROS production as a part of its mechanism of action, resulting in decreased ΔΨm and reduced intracellular ATP concentrations. These actions ultimately culminate in parasite death. Furthermore, our data suggest that EGCG is orally effective in the treatment of L. braziliensis-infected BALB/c mice without altering serological toxicity markers.

Effect of crude extracts of Moringa stenopetala and Artemisia absinthium on parasitaemia of mice infected with Trypanosoma congolense

Background

Treatment of trypanosomosis is currently facing a number of problems including toxicity of trypanocidal drugs and development of resistance by the parasites. These limitations have prompted the search for alternative active substances (such as of natural origin). The purpose of the study was to investigate the effect of extracts of Moringa stenopetala and Artemisia absinthium on Trypanosoma congolense in mice.

Methods

Swiss white male mice aged 8–12 weeks were divided into six experimental groups of six animals. Water and methanol extracts of the two plants were prepared. T. congolense was isolated from cattle at Ghibe valley (Ethiopia). All experimental mice received approximately 1 x 10⁵ trypanosomes in 0.2 ml of blood. Plant extracts were given orally to four groups (2 plant species and two extraction methods) at 400 mg/kg body weight for seven consecutive days. One group remained as distilled water treated control and the other as diminzene aceturate treated control. The effect of the extracts on levels of parasitaemia, body weight, packed cell volume (PCV) and mice survival was monitored for 25 days.

Results

All treatments have significantly reduced parasitaemia and helped improve body weight, PCV and survival of mice compared to the water-treated control (P < 0.01 in all cases). These effects were comparable to that with diminazene aceturate. No significant difference was observed in the reduction of parasitaemia between plant extract treatment groups. However, mice with extracts of A. absinthium had significantly higher body weight than those with extracts of M. stenopetala (P < 0.05).

Conclusions

The two plants have antitrypanosomal potential against T. congolense by reducing the levels of parasitaemia, maintaining good PCV and body weight, and prolonging the lives of infected animals.

Antileishmanial activity of a mixture of Tridax procumbens and Allium sativum in mice

We tested a mixture of Tridax procumbens, known for its direct action against Leishmania mexicana, and Allium sativum, known for its immunomodulatory effect, as an alternative to treat cutaneous leishmaniasis. Acute oral toxicity was tested with the Up-and-Down Procedure (UDP) using a group of healthy mice administered with either T. procumbens or A. sativum extracts and compared with a control group. Liver injury and other parameters of toxicity were determined in mice at day 14. The in vivo assay was performed with mice infected with L. mexicana promastigotes and treated with either a mixture of T. procumbens and A. sativum or each extract separately. The thickness of the mice’s footpads was measured weekly. After the 12-week period of infection, blood samples were obtained by cardiac puncture to determine the total IgG, IgG1 and IgG2a immunoglobulins by a noncommercial indirect ELISA. We showed that the mixture of T. procumbens and A. sativum extracts was better at controlling L. mexicana infection while not being toxic when tested in the acute oral toxicity assay in mice. An increase in the ratio of IgG2a/IgG1 indicated a tendency to raise a Th1-type immune response in mice treated with the mixture. The mixture of T. procumbens and A. sativum extracts is a promising natural treatment for cutaneous leishmaniasis and its healing effects make it a good candidate for a possible new phytomedicine.

The potential of anti-malarial compounds derived from African medicinal plants, part II: a pharmacological evaluation of non-alkaloids and non-terpenoids

Malaria is currently a public health concern in many countries in the world due to various factors which are not yet under check. Drug discovery projects targeting malaria often resort to natural sources in the search for lead compounds. A survey of the literature has led to a summary of the major findings regarding plant-derived compounds from African flora, which have shown anti-malarial/antiplasmodial activities, tested by in vitro and in vivo assays. Considerations have been given to compounds with activities ranging from "very active" to "weakly active", leading to >500 chemical structures, mainly alkaloids, terpenoids, flavonoids, coumarins, phenolics, polyacetylenes, xanthones, quinones, steroids and lignans. However, only the compounds that showed anti-malarial activity, from "very active" to "moderately active", are discussed in this review.

In Vitro Effect of Aqueous Extract and Fraction IV Portion of Ximenia americana Stem Bark on Trypanosoma congolense DNA

Trypanosomosis is a debilitating disease affecting mainly livestock and humans in tropical Africa. Chemically synthesized drugs and medicinal plants have been used in the treatment and control of this disease. In this study, the in vitro effect of aqueous extracts and fraction IV extract of Ximenia americana stem bark on Trypanosoma congolense DNA was investigated. The extracts were incubated with the parasites in vitro at 300 mg/mL aqueous extract and 25 mg/mL fraction IV portion for 30, 60, and 120 mins. The DNA of the trypanosomes was isolated and digested using ECOR1 enzyme and subsequently PCR was carried out. Results showed that aqueous extract and fraction IV portion immobilized 55% and 90% of the trypanosomes after 30-minute incubation. Subsequent isolation of the parasite DNA and agarose gel electrophoresis did not reveal that cell death was as a result of DNA fragmentation. This suggests that cell death was by another mechanism of action.

Anthelmintic activity of phenolic acids from the axlewood tree Anogeissus leiocarpus on the filarial nematode Onchocerca ochengi and drug-resistant strains of the free-living nematode Caenorhabditis elegans

The effect of three phenols (ellagic, gentisic and gallic acids) from the axlewood tree Anogeissus leiocarpus on Onchocerca ochengi and drug-resistant strains of Caenorhabditis elegans, a model organism for research on nematode parasites, is investigated. Worms were incubated in different concentrations of phenols and their survival was monitored after 48 h. Among the three acids, ellagic acid strongly affected the survival of O. ochengi microfilariae, O. ochengi adults, a wild-type C. elegans and anthelmintic-resistant strains of C. elegans, namely albendazole (CB3474), levamisole (CB211, ZZ16) and ivermectin (VC722, DA1316), with LC50 values ranging from 0.03 mm to 0.96 mm. These results indicate that the binding of ellagic acid in the worm differs from that of resistant strains of C. elegans. The efficacy of both gallic and gentisic acids was not significantly changed in resistant strains of C. elegans treated with levamisole (ZZ16, LC50= 9.98 mm, with gallic acid), albendazole (CB3474, LC50= 7.81 mm, with gentisic acid) and ivermectin (DA1316, LC50= 10.62 mm, with gentisic acid). The efficacy of these three pure compounds is in accordance with the use of A. leiocarpus from its locality of origin. The in vivo toxicity data reveal that the thresholds are up to 200 times higher than the determined LC50 values. Thus, ellagic acid could be a potential option for the treatment of nematode infections, even in cases of drug resistance towards established anthelmintic drugs.

In vitro antiplasmodial and cytotoxic properties of some medicinal plants from western Burkina Faso

Background

Resistance of malaria parasites to existing drugs complicates treatment, but an antimalarial vaccine that could protect against this disease is not yet available. It is therefore necessary to find new effective and affordable medicines. Medicinal plants could be a potential source of antimalarial agents. Some medicinal plants from Burkina Faso were evaluated for their antiplasmodial and cytotoxic properties in vitro.

Methods

Crude dichloromethane, methanol, water-methanol, aqueous and alkaloids extracts were prepared for 12 parts of 10 plants. Chloroquine-resistant malaria strain K1 was used for the in vitro sensibility assay. The Plasmodium lactacte dehydrogenase technique was used to determine the 50% inhibitory concentration of parasites activity (IC₅₀). The cytotoxic effects were determined with HepG2 cells, using the tetrazolium-based colorimetric technique, and the selectivity index (SI) was calculated.

Results

Sixty crude extracts were prepared. Seven extracts from Terminalia avicenoides showed IC₅₀ < 5 µg/mL. The IC₅₀ of dichloromethane, methanol, aqueous and alkaloids extracts ranged between 1.6 µg/mL and 4.5 µg/mL. Three crude extracts from Combretum collinum and three from Ficus capraefolia had an IC₅₀ ranging between 0.2 µg/mL and 2.5 µg/mL. Crude extracts from these three plants had no cytotoxic effect, with SI > 1. The other plants have mostly moderate or no antimalarial effects. Some extracts from Cordia myxa, Ficus capraefolia and Opilia celtidifolia showed cytotoxicity, with an SI ranging between 0.4 and 0.9.

Conclusion

Our study showed a good antiplasmodial in vitro activity of Terminalia avicenoides, Combretum collinum and Ficus capraefolia. These three plants may contain antiplasmodial molecules that could be isolated by bio-guided phytochemical studies.

Bioactivities of the genus Combretum (Combretaceae): a review

The Combretaceae is a large family of herbs, shrubs and trees, comprising about 20 genera and 600 species with tropical distribution around the globe and centers of diversity in Africa and Asia. Some Combretum species are extensively used in traditional medicine against inflammation, infections, diabetes, malaria, bleeding, diarrhea and digestive disorders and others as a diuretic. The present work is a literature survey of Combretum species that have been evaluated for their ability to exert biological activities. A total number of 36 Combretum species are discussed with regard to plant parts used, component tested and bioassay models. This review is of fundamental importance to promoting studies on Combretum species, thereby contributing to the development of new therapeutic alternatives that may improve the health of people suffering from various health problems.

Mitochondrial damage contribute to epigallocatechin-3-gallate induced death in Leishmania amazonensis

Epigallocatechin-3-gallate (EGCG), the most abundant flavonoid in green tea, has been reported to have antiproliferative effects on Trypanosoma cruzi however, the mechanism of protozoan action of EGCG has not been studied. In the present study, we demonstrate the mechanism for the antileishmanial activity of EGCG against Leishmania amazonensis promastigotes. Incubation with EGCG significantly inhibited L. amazonensis promastigote proliferation in a time- and dose-dependent manner. The IC(50) for EGCG at 120 h was 0.063 mM. Ultrastructural alterations of the mitochondria were observed in promastigote treated with EGCG, being the organelle injury reinforced by the decrease in rhodamine 123 fluorescence. The effects of several drugs that interfere directly with mitochondrial physiology in parasites such as Leishmania have been described. The unique mitochondrial features of Leishmania make this organelle an ideal drug target while minimizing toxicity. These data suggest mitochondrial collapse as a part of the EGCG mechanism of action and demonstrate the leishmanicidal effect of EGCG.

In vitro antimicrobial activity of Combretum molle (Combretaceae) against Staphylococcus aureus and Streptococcus agalactiae isolated from crossbred dairy cows with clinical mastitis

Following the rapidly expanding dairy enterprise, mastitis has remained the most economically damaging disease. The objective of this study was mainly to investigate the in vitro antibacterial activities of ethanol extracts of Combretum molle (R.Br.Ex.G.Don) Engl & Diels (Combretaceae) against antibiotic-resistant and susceptible Staphylococcus aureus and Streptococcus agalactiae isolated from clinical cases of bovine mastitis using agar disc diffusion method. The leaf and bark extracts showed antibacterial activity against S. aureus at concentrations of 3 mg/ml while the stem and seed extract did not show any bioactivity. Although both leaf and bark extracts were handled in the same manner, the antibacterial activity of the bark extract against the bacterial strains had declined gradually to a lower level as time advanced after extraction. The leaf extract had sustained bioactivity for longer duration. The susceptibility of the bacteria to the leaf extract is not obviously different between S. aureus and S. agalactiae. Also, there was no difference in susceptibility to the leaf extract between the antibiotic-resistant and antibiotic-sensitive bacteria. Further phytochemical and in vivo efficacy and safety studies are required to evaluate the therapeutic value of the plant against bovine mastitis.

Antiplasmodial activity of New Caledonia and Vanuatu traditional medicines

CONTEXT

With the emergence of strains multiresistant to antimalarial drugs, the search for new active molecules remains a priority. Ethnopharmacology appears to be a good method of selection in such investigations.

OBJECTIVE

The aim of this research work is to select plants used in Melanesian traditional medicine, in New Caledonia and Vanuatu, which should be a promising source for the isolation of new antimalarial drugs.

MATERIALS AND METHODS

Forty-seven plant extracts belonging to 12 families, traditionally used by the Melanesian people or belonging to an antimalarial known genus, were screened in vitro for antimalarial activity on Plasmodium falciparum chloroquine (CQ)-resistant (FcB1) and CQ-sensitive (HB3) strains. They were also tested for their inhibitory effects on a protein kinase (Pfnek) and their cytotoxicity on human breast adenocarcinoma (MCF7) cells.

RESULTS

Among all extracts, four displayed strong in vitro activities against P. falciparum: Gardenia urvillei Montrouzier, Scleria polycarpa Boeckeler, Terminalia catappa L. and Acronychia laevis J.R. & J.G. Forster, the latter being also toxic on MCF7 cells. Except for the extracts of S. polycarpa, all others that were active on P. falciparum, also possess an inhibitory effect on Pfnek.

DISCUSSION AND CONCLUSION

These results confirm that ethnopharmacology is an excellent approach for such investigations. The two countries considered clearly present advantages in the field. Indeed, local populations keep their traditional knowledge alive, and their flora is exceptionally rich. In New Caledonia, the high endemicity rate (74%) ranks the island as one of the world's biodiversity hotspots. As a consequence, chances to discover new active natural compounds are also high.

Structural features and biological properties of ellagitannins in some plant families of the order Myrtales

Plant tannins, including hydrolysable and condensed varieties, are well known antioxidants in medicinal plants, foods, and edible fruits. Their diverse biological properties and potential for disease prevention have been demonstrated by various in vitro and in vivo assays. A number of ellagitannins, the largest group of hydrolysable tannins, have been isolated from dicotyledoneous angiosperms and characterized. This diverse class of tannins is sub-grouped into simple ellagitannins, C-glycosidic ellagitannins, complex tannins (condensates of C-glycosidic tannins with flavan-3-ol), and oligomers up to pentamers. This review outlines and describes the chemotaxonomic significance of structural features in various types of ellagitannins found in plants belonging to the Myrtaceae, Onagraceae, and Melastomataceae families, which are all included in the order Myrtales. Any biological activities that have been reported, including antitumor and antibacterial effects as well as enzyme inhibition, are also reviewed.

Antiplasmodial activity and toxicity of crude extracts from alternatives parts of plants widely used for the treatment of malaria in Burkina Faso: contribution for their preservation

In order to prevent the destruction of the ecology and to sustain the flora mainly for medicinal plants, we investigated on alternative parts taken from four plants already known to display antiplasmodial activities and largely used by traditional healers in sub-Saharan Africa. The evaluated parts are bark of trunk for Zanthoxylum zanthoxyloides and leaves for Sarcocephalus latifolius instead of roots, and leaves for Combretum molle and Anogeissus leiocarpus instead of stem bark. The antiplasmodial activity of extracts of these plants was evaluated in vitro using the multi-resistant strain (W2) of Plasmodium falciparum. Antiproliferative activity was also assessed, using K562S human monocyte cell lines, along with calculation of the selectivity index (SI) of each extract. The highest in vitro antiplasmodial activity was found in the alkaloid extract of trunk bark from Z. zanthoxyloides and from the MeOH extract of A. leiocarpus leaves (IC(50) = 1.2 microg/mL and 4.9 microg/mL, respectively) with good selectivity index. Moderate activity was found in the MeOH extract (IC(50) = 5.7 microg/mL) and MeOH/H2O extract (IC(50) = 7.9 microg/mL) of C. molle leaves. Moderate activity was also found in the MeOH/H20 extract (IC(50) = 5.2 microg/mL) and the decoction (IC(50) = 8.2 microg/mL) from leaves of A. leiocarpus. No good activity was found with extracts from roots of S. latifolius. All extracts tested displayed low levels of cytotoxicity against K562S cells. The data generated clearly show that the trunk bark for Z. zanthoxyloides and the leaves for A. leiocarpus and C. molle could be used for the treatment of malaria instead of roots and stem bark.

Comparative molecular docking of antitrypanosomal natural products into multiple Trypanosoma brucei drug targets

Antitrypanosomal natural products with different structural motifs previously shown to have growth inhibitory activity against Trypanosoma brucei were docked into validated drug targets of the parasite, which include trypanothione reductase, rhodesain, farnesyl diphosphate synthase, and triosephosphate isomerase. The in-silico calculations predicted that lowest energy docked poses of a number of the compounds can interact with catalysis-dependent residues, thus making them possible catalytic inhibitors and of course physiologically active. Compounds that possess a number of hydrogen-bond-accepting and/or -donating groups like phenolics and quinones show extensive interactions with the targets. Compounds like cissampeloflavone, 3-geranylemodin and ningpogenin thus offer profound promise.

Ethnopharmacological survey of six medicinal plants from Mali, West-Africa

An ethnopharmacological survey was carried out to collect information about the use of six medicinal plants in the regions around Siby and Dioila, Mali. The plants investigated were Biopyhtum petersianum, Cola cordifolia, Combretum molle, Opilia celtidifolia, Parkia biglobosa and Ximenia americana. More than 60 medical indications were reported for the use of these plants in traditional medicine. The most frequently reported ailments were malaria (25.6%), different types of pain (14.0%) and dermatitis (7.4%). The main forms for preparation were decoction (58.1%) and powdered plant material (28.4%). The most frequent used plant parts were leaves (37.7%) and stem bark (18.6%). The healers' consensus for the main indications is fairly high for the four plants B. petersianum, C. cordifolia, C. molle and O. celtidifolia, and this supports the traditional use of these plants. However for P. biglobosa and X. americana the healers' consensus is less consistent and it is more difficult to draw conclusions about the most important traditional use of these two plants.