Evaluation of the hepatotoxic and hepatoprotective effect of Rwandese herbal drugs on in vivo (guinea pigs barbiturate-induced sleeping time) and in vitro (rat precision-cut liver slices, PCLS) models

A Comparative GC/MS Analysis of Citrus Essential Oils: Unveiling the Potential Benefits of Herb-Drug Interactions in Preventing Paracetamol-Induced Hepatotoxicity

Our study aimed to test the potential of Citrus oils in protecting against paracetamol (PAR)-induced hepatotoxicity. The essential oils of Pineapple sweet orange (OO), Murcott mandarin (MO), Red grapefruit (GO), and Oval kumquat (KO) were investigated using gas chromatography coupled with mass spectrometry (GC/MS). Twenty-seven compounds were identified, with monoterpene hydrocarbons being abundant class. d-Limonene had the highest percentage (92.98 %, 92.82 %, 89.75 %, and 94.46 % in OO, MO, GO, and KO, respectively). Hierarchical cluster analysis (HCA) and principal components analysis (PCA) revealed that octanal, linalool, germacrene D, and d-limonene were the principal discriminatory metabolites that segregated the samples into three distinct clusters. In vitro antioxidant capacities were ranged from 1.2-12.27, 1.79-5.91, and 235.05-585.28 μM Trolox eq/mg oil for 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic (ABTS), ferric-reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC), respectively. In vivo, citrus oils exhibited a significant reduction in alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and nitric oxide (NO). Additionally, there was an increase in glutathione reductase (GSH), and the liver architecture was nearly normal. Molecular docking revealed that d-limonene exhibited a good inhibitory interaction with cytochrome P450 (CYP450) isoforms 1A2, 3A4, and 2E1, with binding energies of -6.17, -4.51, and -5.61 kcal/mol, respectively.

Sub-chronic toxicity of the aqueous leaf extract of Ocimum lamiifolium Hochst. ex Benth on biochemical parameters and histopathology of liver and kidney in rats: in vivo and in- silico toxicity studies

BACKGROUND

The aerial part of Ocimum lamiifolium is commonly used in Ethiopian traditional medicine. Although this plant is mostly used in traditional medicine, its safety profile has not been documented yet. The aim of this study was to assess the sub-chronic toxicity of O. lamiifolium aqueous extract in rats and to determine the toxicity profile of GC-MS identified bioactive compounds obtained from essential oil of O. lamiifolium using in silico toxicity methods.

METHODS

Eighty rats (40 male and 40 female) were randomly assigned to four groups of ten rats per sex/group. For 90 days, Groups I-III received 200, 400, and 600 mg/kg bw of aqueous extract of O. lamiifolium, respectively. Distilled water was given to Group IV (control). Clinical observations, food intake, and rat weight were all recorded during the experiment. In addition, several biochemical parameters, organ weight, and histology of the liver and kidney were all evaluated. For the in-silico toxicity study, GC-MS identified bioactive compounds in O. lamiifolium essential oil were obtained from published articles. The compounds two-dimensional structures were constructed using Chemdraw. The two-dimensional structures were converted into a simplified molecular input line entry system (SMILES) using the Swiss ADMET web tool. Furthermore, the toxicity parameters were predicted using the ProTox II server.

RESULTS

The administration of an aqueous extract of O. lamiifolium leaves significantly (p < 0.05) reduced the test animals' food intake and body weight gain. In the high dose (600 mg/kg bw) treated group, the serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase levels were significantly increased (p < 0.05). In female rats given 600 mg/kg bw of O. lamiifolium, the levels of serum urea were also increased. In addition, rats given 600 mg/kg bw had significantly lower blood glucose levels than the control group (p < 0.05). Doses up to 400 mg/kg bw didn't bring a significant change to the histology of the liver. However, in the high dose (600 mg/kg bw) treated group, some female rats' livers showed mild sinusoidal and central vein dilatation, as well as parenchymal necrosis. our findings showed that all compounds derived from the essential oil of O. lamiifolium showed no mutagenicity or cytotoxicity. However, 30% of the compounds tested were hepatotoxic, 20% carcinogenic, and 20% immunotoxin.

CONCLUSION

Our findings showed that oral administration of O. lamiifoliums aqueous extract up to a dose of 400 mg/kg bw is not toxic. However, high-dose (600 mg/kg bw) significantly affected the food consumption and weight gain of the experimental rats and the serum concentration of some liver and kidney enzymes were also significantly increased. Additionally, a considerable proportion of the tested compounds were predicted to be hepatotoxic, carcinogenic and immunotoxin. Furthermore, before employing O. lamiifolium preparations as drugs, a chronic toxicity research on the essential oil as well as its components that exhibited toxicity in the in-silico toxicity study is needed. Finally, use high doses of O. lamiifolium leaves with caution.

Acetaminophen induced hepatotoxicity: An overview of the promising protective effects of natural products and herbal formulations

BACKGROUND

The liver plays an important role in regulating the metabolic processes and is the most frequently targeted organ by toxic chemicals. Acetaminophen (APAP) is a well-known anti-allergic, anti-pyretic, non-steroidal anti-inflammatory drug (NSAID), which upon overdose leads to hepatotoxicity, the major adverse event of this over-the-counter drug.

PURPOSE

APAP overdose induced acute liver injury is the second most common cause that often requires liver transplantation worldwide, for which N-acetyl cysteine is the only synthetic drug clinically approved as an antidote. So, it was felt that there is a need for the novel therapeutic approach for the treatment of liver diseases with less adverse effects. This review provides detailed analysis of the different plant extracts; phytochemicals and herbal formulations for the amelioration of APAP-induced liver injury.

METHOD

The data was collected using different online resources including PubMed, ScienceDirect, Google Scholar, Springer, and Web of Science using keywords given below.

RESULTS

Over the past decades various reports have revealed that plant-based approaches may be a better treatment choice for the APAP-induced hepatotoxicity in pre-clinical experimental conditions. Moreover, herbal compounds provide several advantages over the synthetic drugs with fewer side effects, easy availability and less cost for the treatment of life-threatening diseases.

CONCLUSION

The current review summarizes the hepatoprotective effects and therapeutic mechanisms of various plant extracts, active phytoconstituents and herbal formulations with potential application against APAP induced hepatotoxicity as the numbers of hepatoprotective natural products are more without clinical relativity. Further, pre-clinical pharmacological research will contribute to the designing of natural products as medicines with encouraging prospects for clinical application.

Antidiarrheal Effect of 80% Methanol Extract and Fractions of the Leaves of Ocimum lamiifolium in Swiss Albino Mice

Introduction

Worldwide, in children of under five years of age, diarrhea is responsible for more than 760,000 annual deaths. It is treated with both modern drugs and traditional medicinal plants, including O. lamiifolium. But the use of this plant as an antidiarrheal agent is not scientifically validated. Therefore, this study was aimed to evaluate antidiarrheal efficacy of the plant.

Method

The leaf powder was macerated by 80% methanol and then fractionated using n-hexane, n-butanol, and distilled water. Antidiarrheal activity was evaluated through different models (castor oil-induced diarrhea, enteropooling, and motility) using onset, number of wet feces, fluid content, weight and volume of intestinal content, and motility as test parameters by administering treatment doses to groups of mice. Group I received 10 mL/kg of the dissolving vehicle, Group II received either loperamide or atropine, and Groups III-V received extract doses of 100, 200, and 400 mg/kg, respectively. One-way ANOVA was used to analyze the data, followed by Tukey's post-hoc test.

Results

The crude extract exhibited a significant effect on the fluid content of feces at all tested doses. Additionally, the n-butanol and distilled water fractions revealed significant effects on onset of diarrhea at 400 mg/kg (p < 0.05), while the n-hexane fraction showed significant effects on number of wet feces, onset, and fluid content of feces at all tried doses. The crude extract and all the fractions (at 200 and 400 mg/kg) decreased the weight and volume of intestinal content significantly. Similarly, both the crude extract and distilled water fraction at 400 mg/kg as well as n-butanol and n-hexane fractions at 200 and 400 mg/kg showed meaningful differences on peristaltic index as compared to the negative control.

Conclusion

The results revealed that the leaf extract of O. lamiifolium has an antidiarrheal activity, which supports the traditional medical practice.

Recent advance of <i>in vitro</i> models in natural phytochemicals absorption and metabolism

Natural phytochemicals absorption and metabolic process are mainly in the human gut. Simulating the absorption and metabolism of natural phytochemicals in vitro to predict the rate and degree of absorption of natural phytochemicals provides convenience for many researchers. However, in this process, many physiological factors <i>in vitro</i> are affected, such as stomach and intestinal juice composition, pH, intestinal transmission rate and so on. In recent years, the research methods have gradually improved to make these models more suitable for the natural phytochemicals absorption process, <i>in vitro</i> simulation models have become an essential means to study natural phytochemicals absorption. Therefore, this paper introduces the advantages and disadvantages of commonly used <i>in vitro</i> simulation models of natural phytochemicals absorption and metabolism, as well as briefly introduces the working principle of each model. To provide a theoretical basis for simulating natural phytochemicals absorption <i>in vitro</i> and development and utilization of natural phytochemicals.

Assessing the protective effect of Crassocephalum vitellinum against Rifampicin-induced hepatotoxicity in Wistar rats

Background

Crassocephalum vitellinum is widely used by traditional medical practitioners and local people in East Africa to manage a large number of ailments including hepatitis 1. However, its hepatoprotective effects had not been evaluated prior to this study. The aim of this study was to assess the effect of an ethanolic leaf extract of Crassocephalum vitellinum against rifampicin-induced liver toxicity in Wistar rats.

Methods

Increasing doses of an ethanolic leaf extract of C. vitellinum were administered to Wistar rats daily for 35 days, together with rifampicin given orally as suspension. After the treatment period, Assessment of hepatoprotective activity was done by analysis of serum levels of biochemical and histopathological effects on the liver.

Results

The results showed that administration of C. vitellinum extract significantly prevented drug- induced increase in serum levels of liver biomarker enzymes and also decreased the hepatocellular necrosis and inflammatory cells infiltration.

Conclusion

The plant extract loweres the liver biomarker enzymes (ALT, ALP, AST) and preserves the histomorphology of the hepatocytes which is suggestive that the plant possess hepatoprotective properties.

Countrywide Survey of Plants Used for Liver Disease Management by Traditional Healers in Burkina Faso

Liver disease is highly prevalent in Africa, especially in the western African country Burkina Faso, due to the presence of multiple biological and chemical aggressors of the liver. Furthermore, diagnosis and appropriate care for liver disease are uneven and usually insufficient. This drives local communities to turn to folk medicine based on medicinal plants from healers. Small scale, ethnopharmacological studies on reputed hepatoprotective plants have been carried out in defined regions worldwide, but so far, no study has been carried out on a countrywide scale. Therefore, we have explored traditional healers’ practices in all thirteen regions of Burkina Faso. We interviewed 575 healers and we compiled a database with 2,006 plant entries. Here, we report results on liver nosology, liver pathologies, medicinal plants used for liver disease, and traditional practices through the lens of Burkinabe healers. Our goal was to give a full inventory of medicinal plants used to treat liver disease and to determine if there was consensus on the use of specific plants for specific symptoms. Analysis of the medicinal plants in use across the whole country provides local communities with a wider evidence base to determine which plants may be more effective in treating liver disease and could provide the scientific community, with a shortlist of plants suitable for chemical and pharmacological investigation to validate the plants’ therapeutic role.

Medicinal plants utilized for hepatic disorders in Ethiopian traditional medical practices: a review

Background

Ethiopia is among the top floral biodiversity rich countries in the world. More than 7000 species of plants, 15% of they are endemic, are reported in the country. Accessibility, cultural enrichment, and cheapness make 80% of the Ethiopian people used indigenous plants for various health ailments and diseases in their traditional medical practices. Therefore, the current review examined the use patterns of medicinal plants utilized for hepatic disorders in Ethiopian traditional medical practices for further scientific investigations.

Methods

Ethnobotanical and related studies on medicinal plants utilized for hepatic disorders in Ethiopia were reviewed. Ethiopian university websites, Google, Google Scholar, PubMed, Medline, and other online internet search engines were used to access literature articles. The number of plant species and families, used parts, used conditions, modes of preparation, and routes of administration were tabulated and summarized using Excel spreadsheet and descriptive statistics, respectively.

Results

The current review showed that 276 plant species belonging to 89 families were used for hepatic disorders in Ethiopian traditional medical practices. The commonly utilized plant families were Asteraceae (10.14%), Fabaceae (9.08%), Euphorbiaceae (7.61%), Laminaceae (4.35%), Solanaceae (3.99%), and Aloaceae (2.90%). Justicia schimperiana (34.34%), Croton macrostachyus, and Phytolacca dodecandra (each 20.20%), Cordia africana, Cucumis ficifolius, and Rumex abyssinica (each 10.10%) were among the most utilized plant species. They were mainly distributed in Oromo (58%), southern (36%), and Amhara (35.5%) regions. Herbs (47.10%), shrubs (26.09%) and trees (20.65%) were their primary growth forms, while leaves (34.30%) and roots (33.06%) were their commonly utilized parts. Pounding (24.59%), decoction (19.67%), powdering (9.84%), and concoction (9.13%) were their major modes of preparations. Water was the most utilized solvent (48.26%) for the remedy preparations, which were mainly administered orally (76.35%).

Conclusions

This review showed that many claimed medicinal plants were utilized for the treatment of hepatic disorders in Ethiopian traditional medical practices. Hence, further experimental investigation is recommended to standardize their quality and phytochemistry and validate their safety and efficacy. Documentation and conservation of indigenous herbal knowledge have also been strengthened.

Herbal Therapy for the Treatment of Acetaminophen-Associated Liver Injury: Recent Advances and Future Perspectives

Acetaminophen (APAP) overdose is the leading cause of drug-induced liver injury worldwide, and mitochondrial oxidative stress is considered the major event responsible for APAP-associated liver injury (ALI). Despite the identification of N-acetyl cysteine, a reactive oxygen species scavenger that is regarded as an effective clinical treatment, therapeutic effectiveness remains limited due to rapid disease progression and diagnosis at a late phase, which leads to the need to explore various therapeutic approaches. Since the early 1990s, a number of natural products and herbs have been found to have hepatoprotective effects against APAP-induced hepatotoxicity in terms of acute liver failure prevention and therapeutic amelioration of ALI. In this review, we summarize the hepatoprotective effects and mechanisms of medicinal plants, including herbs and fruit extracts, along with future perspectives that may provide guidance to improve the current status of herbal therapy against ALI.

Hepatoprotective effect of silver nanoparticles synthesized using aqueous leaf extract of Rhizophora apiculata

Background: Liver plays a vital role in the elimination of xenobiotics that can induce hepatotoxicity in living organisms.Silver nanoparticles have evolved recently as an alternative in various industries and are used for their biomedical applications.Rhizophora apiculata is a least studied mangrove-based plant that has been used in the traditional medicine of Southeast Asia for its healing properties. It is a well-known fact that the generation of free radicals has been associated with oxidative stress.  Methods: Hence, in this study we used carbon tetrachloride as a hepatotoxin to induce liver damage. The protective effects of silver nanoparticles synthesized using Rhizophora apiculata on hepatotoxin-induced liver damage in experimental mice were assessed.  Results: The results of the assessment indicate that silver nanoparticles were effective in protecting the liver from damages induced by carbon tetrachloride.  Conclusion: Among existing literature, this is the first ever approach for hepatoprotective effect of nanoparticles derived using plant extract from mangrove ecosystem.

Knowledge and demand for medicinal plants used in the treatment and management of diabetes in Nyeri County, Kenya

ETHNOPHARMACOLOGICAL RELEVANCE

Non communicable diseases are currently a major health challenge facing humanity. Nyeri County has one of the highest diabetes prevalence in Kenya (12.6%), compared to the country's prevalence of 5.6%. The purpose of the study was to document; diabetes knowledge, medicinal plants and demand for the services of traditional medicine practitioners, in the management and treatment of diabetes.

METHODS

A cross-sectional study was carried out in the six constituencies in Nyeri, using pre-tested semi-structured questionnaires. Thirty practicing traditional medicine practitioners were purposively selected for the study. Field observation and identification was carried out on all plants that were cited during the interview. Plant samples were collected and voucher specimen deposited in the University of Nairobi Herbarium in the - School of Biological Sciences.

RESULTS

The study revealed 30 plant species in 28 genera and 23 families that are used by the traditional medicine practitioners to treat and manage diabetes. Demand for traditional medicine practitioners' services in the treatment of diabetes is low and often occurs when conventional drugs fail.

CONCLUSION

Interaction with the TMPs unveiled significant diversity of potential anti diabetic medicinal plants and in-depth ethnobotanical knowledge that they possessed. Preference for traditional herbal medicine was low despite wide ethnobotanical knowledge in the face of high prevalence of diabetes in the locality. The findings form the basis of pharmacological studies for standardization of the documented ethnomedicine used in the treatment and management of diabetes in the study area.

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.

In vitro antimicrobial activity of plants used in traditional medicine in Gurage and Silti Zones, south central Ethiopia

BACKGROUND

To overcome the escalating problems associated with infectious diseases and drug resistance, discovery of new antimicrobials is crucial. The present study aimed to carry out in vitro antimicrobial analysis of 15 medicinal plant species selected according to their traditional medicinal uses in Gurage and Silti Zones, south central Ethiopia.

METHODS

Ethanol extracts of various plant parts were investigated for their antimicrobial activity against 20 bacterial and one yeast strains. The minimum inhibitory concentration (MIC) was determined by broth microdilution method.

RESULTS

Asparagus africanus, Guizotia schimperi, Lippia adoensis var. adoensis and Premna schimperi were active against Candida albicans, Enterococcus faecalis and Staphylococcus aureus at a concentration of 512 μg/ml or lower. Strong antibacterial activity (MIC≥128 μg/ml) was observed for G. schimperi extract against 17 resistant and sensitive Staphylococcus strains, at a concentration comparable to standard antibiotics. Moreover, this extract showed higher antibacterial activity for the test against S. aureus ATCC 33591, ATCC 33592, SA3 and SA5 strains (128-256 μg/ml) than oxacillin (512 μg/ml).

CONCLUSIONS

The study revealed in vitro antibacterial activity of plants used in folk medicine in south central Ethiopia. The usefulness of these plants, in particular of G. schimperi, should be confirmed through further phytochemical and toxicity analyses.

Towards comprehension of complex chemical evolution and diversification of terpene and phenylpropanoid pathways in Ocimum species

Evolution of chemical diversity and diversification of terpene and phenylpropanoid pathway inOcimumspecies.

Antioxidant and prophylactic effects of Delonix elata L., stem bark extracts, and flavonoid isolated quercetin against carbon tetrachloride-induced hepatotoxicity in rats

Delonix elata L. (Ceasalpinaceae), is widely used by the traditional medical practitioners of Karnataka, India, to cure jaundice, and bronchial and rheumatic problems. The objective of this study was to screen the in vitro antioxidant and hepatoprotective activity of the stem bark extracts against CCl4-induced liver damage in rats. Among different stem bark extracts tested, the ethanol extract (DSE) has shown significant in vitro antioxidant property in radicals scavenging, metal chelating, and lipid peroxidation inhibition assays. HPLC analysis of the DSE revealed the presence of known antioxidant molecules, namely, gallic acid, ellagic acid, coumaric acid, quercetin, and rutin. Bioassay-guided fractionation of DSE has resulted in the isolation and characterization of quercetin. DSE and quercetin have shown significant prophylactic effects by restoring the liver function markers (AST, ALT, ALP, serum bilirubin, and total protein) and antioxidant enzymes (SOD, CAT, GPx, and GST). These results were proved to be hepatoprotective at par with silymarin and well supported by the histological observations of liver sections with distinct hepatic cells, and mild degree of fatty change and necrosis. The results indicated that the DSE and quercetin were significant for prophylactic activity against CCl4-induced liver damage in rats. This activity could be attributed to the antioxidant constituents in the DSE and hence justified the ethnomedicinal claims.

Antimicrobial activity, acute toxicity and cytoprotective effect of Crassocephalum vitellinum (Benth.) S. Moore extract in a rat ethanol-HCl gastric ulcer model

BACKGROUND

A decoction of Crassocephallum vitellinum (Benth.) S. Moore (Asteraceae) is used in Kagera Region to treat peptic ulcers. This study seeks to evaluate an aqueous ethanol extract of aerial parts of the plant for safety and efficacy.

METHODS

An 80% ethanolic extract of C. vitellinum at doses of 100, 200, 400 and 800 mg/kg body wt was evaluated for ability to protect Sprague Dawley rats from acidified ethanol gastric ulceration in comparison with 40 mg/kg body wt pantoprazole. The extract and its dichloromethane, ethyl acetate, and aqueous fractions were also evaluated for acute toxicity in mice, brine shrimp toxicity, and antibacterial activity against four Gram negative bacteria; Escherichia coli (ATCC 25922), Salmonella typhi (NCTC 8385), Vibrio cholera (clinical isolate), and Streptococcus faecalis (clinical isolate). The groups of phytochemicals present in the extract were also determined.

RESULTS

The ethanolic extract of C. vitellinum dose-dependently protected rat gastric mucosa against ethanol/HCl insult to a maximum of 88.3% at 800 mg/kg body wt, affording the same level of protection as by 40 mg/kg body wt pantoprazole. The extract also exhibited weak antibacterial activity against S. typhi and E. coli, while its ethyl acetate, dichloromethane and aqueous fractions showed weak activity against K. pneumonia, S.typhi, E. coli and V. cholera. The extract was non-toxic to mice up to 5000 mg/kg body wt, and the total extract (LC50 = 37.49 μg/ml) and the aqueous (LC50 = 87.92 μg/ml), ethyl acetate (LC50 = 119.45 μg/ml) and dichloromethane fractions (88.79 μg/ml) showed low toxicity against brine shrimps. Phytochemical screening showed that the extract contains tannins, saponins, flavonoids, and terpenoids.

CONCLUSION

The results support the claims by traditional healers that a decoction of C.vitellinum has antiulcer activity. The mechanism of cytoprotection is yet to be determined but the phenolic compounds present in the extract may contribute to its protective actions. However, the dose conferring gastro-protection in the rat is too big to be translated to clinical application; thus bioassay guided fractionation to identify active compound/s or fractions is needed, and use of more peptic ulcer models to determine the mechanism for the protective action.

Models of hepatotoxicity and the underlying cellular, biochemical and immunological mechanism(s): a critical discussion

Liver is a primary organ involved in biotransformation of food and drugs. Hepatic diseases are a major worldwide problem. Hepatic disorders are mainly caused by toxic chemicals (alcohol), xenobiotics (carbon tetrachloride, chlorinated hydrocarbons and gases CO₂ and O₂) anticancer (azathioprine, doxorubicin, cisplatin), immunosuppressant (cyclosporine), analgesic anti-inflammatory (paracetamol, thioacetamide), anti-tubercular (isoniazid, rifampicin) drugs, biologicals (Bacillus-Calmette-Guerin vaccine), radiations (gamma radiations), heavy metals (cadmium, arsenic), mycotoxin (aflatoxin), galactosamine, lipopolysaccharides, etc. Various risk factors for hepatic injury include concomitant hepatic diseases, age, gender, alcoholism, nutrition and genetic polymorphisms of cytochrome P450 enzymes have also been emphasized. The present review enumerates various in vivo animal models and in vitro methods of hepatic injury using diverse toxicants, their probable metabolic pathways, and numerous biochemical changes viz. serum biomarkers enzymes, liver function, oxidative stress associated events like free radicals formation, lipid peroxidation, enzyme antioxidants and participation of cytokines (tumour necrosis factor-α, transforming growth factor-β, tumour necrosis factor-related apoptosis inducing ligand), and other biomolecules (Fas and C-jun N-terminal kinase) are also discussed. The underlying cellular, molecular, immunological, and biochemical mechanism(s) of action responsible for liver damage (toxicity) are also been discussed. This review should be immensely useful for researchers especially for phytochemists, pharmacologists and toxicologists working on hepatotoxicity, hepatotoxic chemicals and drugs, hepatoprotective agents and drug research organizations involved especially in phytopharmaceuticals and other natural products.

Tyrosinase modulation by five Rwandese herbal medicines traditionally used for skin treatment

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional herbal medicines provide an interesting, largely unexplored source for the development of potential new drugs and skin-care cosmetics. Some herbal extracts are known to be inhibitors of melanin formation, sometimes more potent than the classical inhibitors, hydroquinone/arbutin or kojic acid, and are not associated with melanocytes cytotoxicity or mutagenicity. Such plants are used in traditional medicine in many countries, particularly in Africa, for skin lightening.

AIM OF THE STUDY

To evaluate in vitro the ability of Rwandese medicinal plants, traditionally used for the treatment of skin (discoloration and attenuation of discolored spots), to modulate pigmentation and tyrosinase activity.

MATERIALS AND METHODS

Based on an ethnopharmacological survey, five herbs [Brillantaisia cicatricosa Lindau (Acanthaceae), Chenopodium ugandae (Aellen) Aellen (Chenopodiaceae), Dolichopentas longiflora Oliv. (Rubiaceae), Protea madiensis Oliv. (Proteaceae) and Sesamum angolense Welw. (Pedaliaceae)] were selected. Twenty-seven extracts, obtained by treating the herbs with increasing polarities solvents, were investigated for their effects on cell viability (MTT test) and on pigmentation: inhibition of the enzyme tyrosinase (colorimetry of reaction products, measurement of enzyme activity, TLC-autography; studies on crude cellular extracts obtained from normal melanocytes and on a mushroom tyrosinase) and measurement of melanogenesis by human melanoma cells.

RESULTS

None of the tested plant extracts were cytotoxic on tested human melanoma cell lines, except for Dolichopentas longiflora (IC50 of leaves n-hexane extract, 4μg/ml for MM028 and 4.5μg/ml for MM001; IC50 of roots ethyl acetate extract, 0.8μg/ml for MM028 and 3.9μg/ml for MM001). Almost all extracts inhibited melanogenesis in a melanoma whole cells overall pigmentation assay, a model reflecting the entire cycle of melanogenesis. All the Protea madiensis extracts quite strongly inhibited melanogenesis and, surprisingly, one of the Dolichopentas longiflora leaves extracts was found to increase melanogenesis. These results were confirmed by the modulation of pigmentation reactions by crude cellular extracts obtained from normal melanocytes; interestingly, one of the extracts (Dolichopentas longiflora ethyl acetate extract) is even more active (61% at 500μg/ml) than kojic acid (<3% at 142μg/ml and 68% at 1421μg/ml). In a mushroom tyrosinase inhibition assay, data obtained on some extracts fairly agree with pigmentation inhibition measured on melanocytes proteins as, for example, the methanol extract of Protea madiensis. While a few others extract display discording data, this probably reflects either differences between human and mushroom tyrosinase, interference with melanocytes enzymes at later steps than tyrosinase or the simultaneous presence of compounds with conflicting activities in a given extract.

CONCLUSIONS

Ethnopharmacological data represent an efficient approach to discover active herbs. Some of the selected medicinal plants clearly show potent tyrosinase inhibitions while one extract significantly increases cell pigmentation; one extract contains potent growth melanocytes inhibitors.

A review of the medicinal potentials of plants of the genus Vernonia (Asteraceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The Vernonia genus has about one thousand species and members of the genus are widely used as food and medicine. The aim of this review is to analyze published data on the ethnomedicinal, ethnoveterinary and zoopharmacognostic uses of plants of the Vernonia genus. This will help to identify the state of ethnopharmacological knowledge in regard to this genus and to propose future research priorities.

MATERIALS AND METHODS

The major scientific databases including SciFinder, Sciencedirect, Medline and Google Scholar were queried for information on Vernonia genus using various keyword combinations. The International Plant Name Index was also used to verify the names of species and authors.

RESULTS

A total of 109 Vernonia species were reported in the literature to have medicinal properties. One hundred and five (105) plants were linked to the treatment or management of 44 human diseases or health conditions. Plants of the genus also feature in ethnoveterinary and zoopharmacognostic practices. A total of 12 vernonia species were identified to be used in ethnoveterinary medicine while 2 species are used in self medication practices by chimpanzees and gorillas. In vitro and in vivo research studies reporting the validation of the medicinal properties of some species were also reviewed. One hundred and three bioactive compounds isolated from various Vernonia species were also identified. Vernonia amygdalina was identified as the most frequently used member of the Vernonia genus. The Vernolides, a class of sesquiterpene lactone were identified as the most studied compounds from the genus and show interesting bioactivity in antiplasmodial, antileishmanial, antischistosomial, cytotoxicity, antimicrobial and anti-inflammatory assays.

CONCLUSION

On the basis of results from a combination of in vitro and in vivo efficacy and toxicity studies reported, Vernonia amygdalina holds the most promise for development into a nutraceutical against diabetes and malaria while Vernonia cinerea has potential against cancer and inflammatory conditions. Vernolide A is so far the most promising single agent from a Vernonia species that has potential for development into an anticancer agent. The other Vernonia species and isolated compounds require further studies to ascertain their medicinal potentials.

Traditional herbal medicine use associated with liver fibrosis in rural Rakai, Uganda

BACKGROUND

Traditional herbal medicines are commonly used in sub-Saharan Africa and some herbs are known to be hepatotoxic. However little is known about the effect of herbal medicines on liver disease in sub-Saharan Africa.

METHODS

500 HIV-infected participants in a rural HIV care program in Rakai, Uganda, were frequency matched to 500 HIV-uninfected participants. Participants were asked about traditional herbal medicine use and assessed for other potential risk factors for liver disease. All participants underwent transient elastography (FibroScan®) to quantify liver fibrosis. The association between herb use and significant liver fibrosis was measured with adjusted prevalence risk ratios (adjPRR) and 95% confidence intervals (CI) using modified Poisson multivariable logistic regression.

RESULTS

19 unique herbs from 13 plant families were used by 42/1000 of all participants, including 9/500 HIV-infected participants. The three most-used plant families were Asteraceae, Fabaceae, and Lamiaceae. Among all participants, use of any herb (adjPRR = 2.2, 95% CI 1.3-3.5, p = 0.002), herbs from the Asteraceae family (adjPRR = 5.0, 95% CI 2.9-8.7, p<0.001), and herbs from the Lamiaceae family (adjPRR = 3.4, 95% CI 1.2-9.2, p = 0.017) were associated with significant liver fibrosis. Among HIV infected participants, use of any herb (adjPRR = 2.3, 95% CI 1.0-5.0, p = 0.044) and use of herbs from the Asteraceae family (adjPRR = 5.0, 95% CI 1.7-14.7, p = 0.004) were associated with increased liver fibrosis.

CONCLUSIONS

Traditional herbal medicine use was independently associated with a substantial increase in significant liver fibrosis in both HIV-infected and HIV-uninfected study participants. Pharmacokinetic and prospective clinical studies are needed to inform herb safety recommendations in sub-Saharan Africa. Counseling about herb use should be part of routine health counseling and counseling of HIV-infected persons in Uganda.

Traditional phytotherapy remedies used in Southern Rwanda for the treatment of liver diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Liver diseases represent a major health problem due to their complications and limited treatment possibilities. In Rwanda, given low accessibility to modern treatments, most people still rely on traditional medicinal plants. The symptomatology of many hepatic troubles (icterus) is evident for traditional healers who have a high probability of selecting efficient herbal medicines.

OBJECTIVES

To document medicines used in the treatment of "hepatitis" in Southern Rwanda with the knowledge, attitudes and practices related to liver disorder recognition, control and treatment.

MATERIALS AND METHODS

56 traditional health practitioners, each a legal representative of an official association, were interviewed and participated in plant collection for the preparation of botanically identified herbarium specimens.

RESULTS

68 multi-component and 65 single-component herbal recipes were identified for the treatment of liver diseases with a total of 86 different herbs from 34 families identified. The most represented were the Asteraceae and the Lamiaceae. Crassocephalum vitellinum, Hypoestes triflora and Erythrina abyssinica were the most widely used plants. The principle of polymedication for complex (i.e. multifactorial) diseases ("Ifumbi" in Rwanda), is a constant in every traditional practice. It is striking that the Rwandese therapy of liver diseases proposes so many single-herb preparations (49% of all herbal preparations). Some of the recorded plants or other species from the same genus have previously been documented for liver protection using various in vivo and in vitro models.

CONCLUSION

Herbal remedies for hepatitis are widely used and highly diverse in Southern Rwanda; further chemical, pharmacological and toxicological studies are clearly required to rationally develop the most important remedies.

Plants used to treat malaria in Nyakayojo sub-county, western Uganda

AIM OF STUDY

We performed an ethnobotanical study of plants used to treat malaria in Nyakayojo sub-county in south western Uganda because malaria in this region, and in Uganda at large, is still the single most important reason for ill health and mortality. Two of the most vulnerable groups affected by malaria are young children and pregnant women and plants are commonly used in their treatment.

MATERIALS AND METHODS

Twenty-eight traditional birth attendants were interviewed about how they used plants to treat malaria. Review of the literature available on all species identified was undertaken.

RESULTS

Altogether 56 plant species were used by the informants, 48 of which have been identified to species level. Thirty-two (67%) of the species used by the respondents are documented for antimalarial use in other studies, and nearly half (44%) have documented anti-plasmodial activity. Fifty-five percent of the species were used by 2 or more of the respondents. The most commonly used species were Vernonia amygdalina, the indigenous Aloe species, Justicia betonica, Vernonia adoensis and Tithonia diversifolia. It was common to use more than one plant in a recipe (43%). The respondents had good knowledge of the symptom of malaria, and fairly good understanding of the causes.

CONCLUSION

The interviews show that the group of traditional birth attendants has an extensive and diverse knowledge on plants used in the treatment of malaria. The literature survey may indicate a possible explanation for the use of several plants.

Antibacterial and dermal toxicological profiles of ethyl acetate extract from Crassocephalum bauchiense (Hutch.) Milne-Redh (Asteraceae)

Background

The emergence in recent years of numerous resistant strains of pathogenic bacteria to a range of formerly efficient antibiotics constitutes a serious threat to public health. Crassocephalum bauchiense, a medicinal herb found in the West Region of Cameroon is used to treat gastrointestinal infections as well as liver disorders. The ethyl acetate extract from the leaves of C. bauchiense was evaluated for its antibacterial activity as well as acute and sub-acute toxicities.

Methods

The plant extract was prepared by maceration in ethyl acetate. Its phytochemical screening was done by standard methods. The broth microdilution method was used to evaluate the in vitro antibacterial activity. The in vivo antibacterial activity of a gel formulation (0.05, 1 and 2% w/v) of this extract was evaluated using a Staphylococcus aureus-induced dermatitis in a murine model. Selected haematological and biochemical parameters were used to evaluate the dermal sub-acute toxicity of the extract in rats.

Results

Phytochemical screening of the C. bauchiense extract revealed the presence of alkaloids, phenols, tannins and sterols. In vitro antibacterial activities were observed against all the tested microorganisms (MIC = 0.04-6.25 mg/ml). Formulated extract-gel (2% w/v) and gentamycin (reference drug) eradicated the microbial infection after five days of treatment. A single dermal dose of this extract up to 32 g/kg body weight (bw) did not produce any visible sign of toxicity. Also, daily dermal application of the C. bauchiense extract gel formulation for 28 days did not show any negative effect, instead some biochemical parameters such as alanine aminotransferase (ALT and AST), low density lipoprotein (LDL), high density lipoprotein (HDL) and triglycerides were significantly (p < 0.05) affected positively.

Conclusion

These results indicate that the C. bauchiense ethyl acetate extract can be used safely for the treatment of some bacterial infections.

Essential oils of four Rwandese hepatoprotective herbs: Gas chromatography-mass spectrometry analysis and antioxidant activities

Following an ethnobotanical survey in Southern Rwanda for hepatoprotective remedies, four food and medicinal plants, Crassocephalum vitellinum, Guizotia scabra, Microglossa pyrifolia and Ocimum lamiifolium, were selected for pharmacological and chemical investigations aiming to validate their reported properties. The chemical compositions of essential oils obtained from leaves were investigated by GC-MS; essential oils and methanolic extracts were evaluated for antioxidant activity by 1,1-diphenyl-2-picryhydrazyl (DPPH) and linoleic acid peroxidation assays. C. vitellinum [limonene (34.8%), (E)-β-ocimene (21.8%), β-pinene (8.5%), α-pinene (6.6%), myrcene (6.3%)], G. scabra [germacrene-d (25.5%), limonene (9.7%), (E)-β-ocimene (6.6%)], M. pyrifolia [germacrene-d (58.3%)] and O. lamiifolium [sabinene (12.2%), alpha phellandrene (11.6%)] volatile oils scavenge DPPH (10%, 39%, 27%, and 11% quercetin equivalents) and inhibit linoleic acid peroxidation (13%, 23%, 20%, and 13% Trolox® equivalents). The four methanolic extracts were quite active on the lipid peroxidation model (93%, 93%, 70%, and 67% Trolox equivalents) with modest activity on DPPH (5%, 10%, 8%, and 11% quercetin equivalents). These properties most probably participate in the four plants hepatoprotective activities reported in ethnopharmacological and/or pharmacological studies.