Phytochemical screening of Tanzanian medicinal plants. I

Targeted and untargeted screening of a plant extract library established from raw materials originating from Upper Austria

Plant extracts rich in phytochemicals are known for their health benefits. Plant extract library from edible plants obtained from the region of Upper Austria was prepared. Food grade extraction procedures were applied, and relevant physico-chemical parameters measured. A focus on polyphenolic compounds revealed a significant correlation between the total phenolic content (measured by a colorimetric assay) and the cumulated concentration of main individual polyphenols (measured by HPLC-DAD), demonstrating the comparability of these parameters. Targeted screening was performed by HPLC-FLD and -MS for the presence of phytomelatonin. 20 extracts were identified with concentrations of up to 1.4 µg/mL of this phytochemical, which attracts much attention from the food industry. Finally, chemometric methods were employed to cluster extracts based on their phenolic compound profile. This approach allows for an informed preselection of extracts without the need for comprehensive chemical analysis.

Phytochemical Analysis and In Vitro and In Vivo Pharmacological Evaluation of Parthenium hysterophorus Linn

The main aim of this research was to explore Parthenium hysterophorus Linn phytochemically and pharmacologically. Phytochemical screening is important for the isolation of active compounds before bulk extraction. The crude extracts and their fractions were screened for enzyme (urease, α-glycosidase, and phosphodiesterase) inhibition assays, in vivo analgesic, anti-inflammatory, and sedative effects. Results indicated the presence of steroids, flavonoids, etc. The crude extracts such as methanol, hexane, aqueous, ethyl acetate, chloroform, and butanol exhibited excellent urease inhibitory activities with IC₅₀ = 43.1 ± 1.24, 31.9 ± 2.21, 31.9 ± 2.21, 57.3 ± 1.27, 49.2 ± 2.16, and 35.3 ± 1.12, respectively, as compared to standard acetohydroxamic acid (20.3 ± 0.43). The extracts (methanol, hexane, aqueous, ethyl acetate, chloroform, and butanol) also showed promising α-glycosidase potency with IC₅₀ = 13.1 ± 0.34, 21.2 ± 1.16, 23.1 ± 0.12, 84.2 ± 2.17, 118.6 ± 3.07, and 840 ± 1.73, respectively against acarbose (840 ± 1.73). The phosphodiesterase activity of the mentioned extracts was also excellent with IC₅₀ = 131.1 ± 2.41, 197.2 ± 3.16, 24.2 ± 0.11, 62.4 ± 2.21, 152.4 ± 1.81, and 55.3 ± 2.15, respectively, against the standard (265.5 ± 2.25). Furthermore, butanol (14.96 ± 1.78), ethyl acetate (18.98 ± 1.71), and methanol (16.87 ± 1.00) showed dose-dependent analgesic effects with a maximum inhibition of acetic acid-induced writhes. Whereas, methanolic and butanol extracts exhibited maximum inhibition of inflammation in the carrageenan paw edema test. The aqueous (p < 0.01) and butanol (p < 0.01) extracts exhibited maximum a sedative effect followed by chloroform (p < 0.05), ethyl acetate (p < 0.05), and methanolic (p < 0.05) fractions as compared to the standard drug. The current research concluded that Parthenium hysterophorus Linn has important phytochemical constituents having inhibitory effects on urease, α-glycosidase, and phosphodiesterase enzymes. Furthermore, the plant has analgesic, anti-inflammatory, and sedative effects. The P. hysterophorus needs to further be explored for the candidate molecules responsible for the abovementioned activities.

Ethnopharmacological Study of Medicinal Plants Used for the Treatment of Cardiovascular Diseases and Their Associated Risk Factors in sub-Saharan Africa

Cardiovascular diseases (CVDs) are the leading cause of global mortality, including deaths arising from non-communicable diseases in sub-Saharan Africa (SSA). Consequently, this study aimed to provide details of medicinal plants (MPs) employed in SSA for the treatment of CVDs and their related risk factors to open new avenues for the discovery of novel drugs. The extensive ethnopharmacological literature survey of these MPs in 41 SSA countries was based on studies from 1982 to 2021. It revealed 1,085 MPs belonging to 218 botanical families, with Fabaceae (9.61%), Asteraceae (6.77%), Apocynaceae (3.93%), Lamiaceae (3.75%), and Rubiaceae (3.66%) being the most represented. Meanwhile, Allium sativum L., Persea americana Mill., Moringa oleifera Lam., Mangifera indica L., and Allium cepa L. are the five most utilised plant species. The preferred plant parts include the leaves (36%), roots (21%), barks (14%), fruits (7%), and seeds (5%), which are mostly prepared by decoction. Benin, Mauritius, Nigeria, South Africa, and Togo had the highest reported use while most of the investigations were on diabetes and hypertension. Despite the nutraceutical advantages of some of these MPs, their general toxicity potential calls for caution in their human long-term use. Overall, the study established the need for governments of SSA countries to validate the efficacy/safety of these MPs as well as provide affordable, accessible, and improved modern healthcare services.

Plant species of the genus Uvaria: ethnobotanical uses, biological activities and phytochemistry

The genus Uvaria (Annonaceae) comprises of climbing or trailing shrubs and rarely trees. Its plant species are widely distributed across tropical Africa, Asia and Australia. The genus Uvaria is known for various ethnobotanical uses including the treatment of tumours and the control of fever. Some of plant species in this genus have been studied for their ethnobotanical uses, biological activities and phytochemistry. The aim of the present study is to give a comprehensive review of plant species from the genus Uvaria in terms of their ethnobotanical uses, biological activities and phytochemistry. This review is expected to lay a foundation for further studies of this genus in terms of ethnobotanical applicability, biological activities and phytochemistry. Since many compounds currently known from the genus Uvaria have not yet been investigated for their biological activities, this review will be useful for future studies in the phytochemical investigations of lead compounds from this genus.

Medicinal Plants with Prospective Benefits in the Management of Peptic Ulcer Diseases in Ghana

Background

The growth or multiplication of harmful microorganisms in addition to harmful human activities has led to many disorders in humans. Consequently, there is a search for medications to treat these disorders. Interestingly, medicines of plant origin are known to be among the most attractive sources of new drugs and have shown promising results in the treatment of various diseases including peptic ulcers. This review, therefore, is aimed at obtaining knowledge on some Ghanaian ethnomedicinal plants used to treat peptic ulcers, their folkloric uses, their phytochemicals, and their antiulcer and related pharmacological activities as well as finding areas for prospective studies.

Methods

Published peer-reviewed articles on ethnomedicinal plants used for the management of peptic ulcers in Ghana from 1967 to 2020 were sourced and used for the study.

Results

In this review, 13 plants were identified which belong to 10 different families including Sapindaceae, Apocynaceae, and Bignoniaceae. The parts most often used for most preparations were the leaves (53%), followed by stem bark and roots (both having the same percentage of use of 17.6%), the whole plant (5.9%), and the rhizomes (5.9%). Azadirachta indica was the only plant that had undergone some patient studies in addition to animal studies. Conclusion. A discussion of various antiulcer activity studies using ulcer models carried out on selected medicinal plants used for the management of peptic ulcer disease in addition to brief information on their folkloric uses and their phytochemical and other pharmacological properties is presented. These medicinal plants may be used in developing herbal products for the management of peptic ulcer disease.

Traditional Medicinal Uses, Phytoconstituents, Bioactivities, and Toxicities of Erythrina abyssinica Lam. ex DC. (Fabaceae): A Systematic Review

Background

Many studies have been undertaken on the medicinal values of Erythrina abyssinica Lam. ex DC. (Fabaceae). The details, however, are highly fragmented in different journals, libraries, and other publication media. This study was therefore conducted to provide a comprehensive report on its ethnobotany, ethnomedicinal uses, phytochemicals, and the available pharmacological evidence supporting its efficacy and safety in traditional medicine.

Method

We collected data using a PROSPERO registered systematic review protocol on the ethnobotany, phytochemistry, and ethnopharmacology of Erythrina abyssinica from 132 reports that were retrieved from electronic databases. Documented local names, morphology, growth habit and habitat, ethnomedicinal and nonmedicinal uses, diseases treated, parts used, method of preparation and administration, extraction and chemical identity of isolated compounds, and efficacy and toxicity of extracts and isolated compounds were captured. Numerical data were summarized into means, percentages, and frequencies and presented as graphs and tables.

Results

Erythrina abyssinica is harvested by traditional herbal medicine practitioners in East, Central, and South African communities to prepare herbal remedies for various human and livestock ailments. These include bacterial and fungal infections, tuberculosis, malaria, HIV/AIDS, diarrhea, cancer, meningitis, inflammatory diseases, urinary tract infections, wounds, diabetes mellitus, and skin and soft tissue injuries. Different extracts and phytochemicals from parts of E. abyssinica have been scientifically proven to possess anti-inflammatory, antibacterial, antioxidant, antiplasmodial, antiproliferative, antifungal, antimycobacterial, antidiarrheal, anti-HIV 1, antidiabetic, and antiobesity activities. This versatile pharmacological activity is due to the abundant flavonoids, alkaloids, and terpenoids present in its different parts.

Conclusion

Erythrina abyssinica is an important ethnomedicinal plant in Africa harboring useful pharmacologically active phytochemicals against various diseases with significant efficacies and minimal toxicity to mammalian cells. Therefore, this plant should be conserved and its potential to provide novel molecules against diseases be explored further. Clinical trials that evaluate the efficacy and safety of extracts and isolated compounds from E. abyssinica are recommended.

The ethnopharmacological literature: An analysis of the scientific landscape

ETHNOPHARMACOLOGICAL RELEVANCE

The research into bioactive natural products originating from medicinal plants, fungi and other organisms has a long history, accumulating abundant and diverse publications. However no quantitative literature analysis has been conducted so far.

AIM OF THE STUDY

Here we analyze the bibliometric data of ethnopharmacology literature and relate the semantic content to the publication and citation data so that the major research themes, contributors, and journals of different time periods could be identified and evaluated.

MATERIALS AND METHODS

Web of Science (WoS) was searched to identify relevant publications. The Analyze function of WoS and bibliometric software (VOSviewer) were utilized to perform the analyses.

RESULTS

Until the end of November 2018, 59,576 publications -linked to 'ethnopharmacology' indexed by WoS, published since 1958 in more than 5600 journals, and contributed by over 20,600 institutions located in more than 200 countries/regions, were identified. The papers were published under four dominating WoS categories, namely pharmacology/pharmacy (34.4%), plant sciences (28.6%), medicinal chemistry (25.3%), and integrative complementary medicine (20.6%). India (14.6%) and China (13.2%) were dominating the publication space. The United States and Brazil also had more than 8.0% contribution each. The rest of the top ten countries/regions were mainly from Asia. There were around ten-fold more original articles (84.6%) than reviews (8.4%).

CONCLUSIONS

Ethnopharmacological research has a consistent focus on food and plant sciences, (bio)chemistry, complementary medicine and pharmacology, with a more limited scientific acceptance in the socio-cultural sciences. Dynamic global contributions have been shifting from developed countries to economically and scientifically emerging countries in Asia, South America and the Middle East. Research on recording medicinal plant species used by traditional medicine continues, but the evaluation of specific properties or treatment effects of extracts and compounds has increased enormously. Moreover increasing attention is paid to some widely distributed natural products, such as curcumin, quercetin, and rutin.

Review of Ethnomedicinal, Phytochemical and Pharmacological Properties of Lannea schweinfurthii (Engl.) Engl

Lannea schweinfurthii is a valuable medicinal plant species among different ethnic groups in tropical Africa. The aim of the current study was to review existing literature on the ethnomedicinal uses, phytochemistry and pharmacological properties of L. schweinfurthii in an effort to evaluate the therapeutic potential of the species. The relevant information on the ethnomedicinal uses, phytochemistry and pharmacological properties of L. schweinfurthii was generated from several sources including books, book chapters, theses, scientific reports and journal articles obtained from the library and internet sources such as SciFinder, Wiley, Web of Science, American Chemical Society publications, PubMed, BMC, Elsevier, Science Direct, Scielo and Scopus. Traditionally, L. schweinfurthii is used against reproductive system disorders, respiratory disorders, injuries, headache, blood system disorders, infections or infestations and gastro-intestinal disorders. The phytochemical compounds that have been isolated from L. schweinfurthii include alkaloids, anthocyanins, flavonoids, glycosides, phenols, saponins, steroids, tannins and terpenoids. The in vitro and animal studies carried out so far from the crude extracts and compounds isolated from the species exhibited acetylcholinesterase inhibitory, anti-apoptotic, antibacterial, antiviral, anti-giardial, anti-inflammatory, antioxidant, antiplasmodial, antitrypanosomal, hepatoprotective, larvicidal and cytotoxicity activities. Detailed ethnopharmacological studies emphasizing clinical and toxicological evaluations are needed to assess efficacy and safety of the species as herbal medicine.

Vangueria madagascariensis Fruit Tree: Nutritional, Phytochemical, Pharmacological, and Primary Health Care Applications as Herbal Medicine

Vangueria madagascariensis J. F. Gmel. is a plant species regarded as an important fruit tree and medicinal plant in sub-Saharan Africa. This study critically reviewed the nutritional value, phytochemistry, medicinal uses, and pharmacological properties of V. madagascariensis. Relevant information on food and medicinal uses of the species was collected from electronic databases such as ISI Web of Knowledge, ProQuest, ScienceDirect, OATD, Scopus, OpenThesis, PubMed, and Google Scholar, and preelectronic literatures were obtained from the university library covering the period 1966 to 2018. Literature studies revealed that V. madagascariensis has been integrated into farming systems as a fruit tree to support income and nutritional security of households in the region. Vangueria madagascariensis is used as a herbal medicine against diabetes, gastrointestinal problems, malaria, pain, parasitic worms, and skin diseases. Phytochemical compounds identified from the species include alcohols, aldehydes, esters, furanoids, ketones, and terpenoids. Pharmacological studies revealed that V. madagascariensis extracts have antibacterial, anticonvulsant, antidiabetic, antifungal, anti-inflammatory, antioxidant, cytotoxicity, antimalarial, and antiplasmodial properties. Vangueria madagascariensis should be subjected to detailed nutritional, pharmacological, and toxicological evaluations aimed at correlating the traditional uses of the species and the scientific evidence as well as establishing the efficacy, clinical relevance, safety, and mechanisms of action of the plant extracts and compounds.

Tannin-rich extracts from Lannea stuhlmannii and Lannea humilis (Anacardiaceae) exhibit hepatoprotective activities in vivo via enhancement of the anti-apoptotic protein Bcl-2

The potential hepatoprotective activities of two Lannea species were explored in vivo. Furthermore, the binding activities of their main polyphenols to the antiapoptotic protein Bcl-2 were investigated. Based on HPLC-MS/MS results, 22 secondary metabolites were characterized in L. stuhlmannii (mainly tannins), while 20 secondary metabolites (mainly sulphated tannins) were identified in L. humilis. Both extracts exhibited substantial antioxidant activities in vitro and counteracted D-galactosamine induced intoxication in rats in vivo and increased the total antioxidant capacity (TAC) of liver tissues. In addition to reducing the elevated levels of AST and total bilirubin, both extracts significantly attenuated the deleterious histopathologic changes in liver after D-galactosamine-intoxication. Also, both extracts protected hepatocytes from apoptotic cell death and increased the expression of the anti-apoptotic protein Bcl-2. The identified compounds from both extracts can bind to the Bcl-2: Bim (BH3) interface with an appreciable binding free energy. Hydrogen and ionic bonds and hydrophobic interactions with amino acid residues in the hydrophobic face of Bim (BH3) domain were discovered. To sum up, L. humilis and L. stuhlmanni exhibited promising hepatoprotective activities in vivo against D-GalN-induced liver injury and their hepatoprotection is due to the antioxidant and anti-apoptotic effects of tannins and proanthocyanidins.

Ethnobotanical survey and toxicity evaluation of medicinal plants used for fungal remedy in the Southern Highlands of Tanzania

Background/Aim:

Some of the antifungal drugs used in the current treatments regime are responding to antimicrobial resistance. In rural areas of Southern Tanzania, indigenous people use antifungal drugs alone or together with medicinal plants to curb the effects of antibiotic resistance. This study documented ethnobotanical information of medicinal plants used for managing fungal infections in the Southern Highlands of Tanzania and further assess their safety.

Materials and Methods:

Ethnobotanical survey was conducted in Makete and Mufindi districts between July 2014 and December 2015 using semi-structured questionnaires followed by two focus group discussions to verify respondents’ information. Cytotoxicity study was conducted on extracts of collected plants using brine shrimp lethality test and analyzed by MS Excel 2013 program.

Results:

During this survey about 46 plant species belonging to 28 families of angiosperms were reported to be traditionally useful in managing fungal and other health conditions. Among these, Terminalia sericea, Aloe nutii, Aloe lateritia, Zanthoxylum chalybeum, Zanthoxylum deremense, and Kigelia africana were frequently mentioned to be used for managing fungal infections. The preparation of these herbals was mostly by boiling plant parts especially the leaves and roots. Cytotoxicity study revealed that most of the plants tested were nontoxic with LC₅₀ > 100 which implies that most compounds from these plants are safe for therapeutic use. The dichloromethane extract of Croton macrostachyus recorded the highest with LC₅₀ value 12.94 µg/ml. The ethnobotanical survey correlated well with documented literature from elsewhere about the bioactivity of most plants.

Conclusions:

The ethnobotanical survey has revealed that traditional healers are rich of knowledge to build on for therapeutic studies. Most of the plants are safe for use; and thus can be considered for further studies on drug discovery.

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.

Solvent effects on phytochemical constituent profiles and antioxidant activities, using four different extraction formulations for analysis of Bucida buceras L. and Phoradendron californicum

BACKGROUND

The present investigation evaluated 4 different solvent compositions for their relative capacity to extract total phenolic and total flavonoid (TF) components of the leaves, trunks, and stems of Bucida buceras L. (Combretaceae), and the stems of Phoradendron californicum (Viscaceae), plus mesquite and oak species endemic to the Southwestern United States, northern Mexico, and tropical regions of Central and South America, as well as to profile the composition of these plant materials and to measure their antioxidant capacity.

METHODS

The total phenolic content of plant material used in the present investigation was measured using the Folin-Ciocalteau assay. Total flavonoids were assayed by AlCl3 and 2,4-dinitrophenylhydrazin colorimetry. Nitroblue tetrazolium was utilized for scavenging of superoxide anion, and in vitro antioxidant activity was evaluated using the 2, 2-diphenyl-1-picrylhydrazyl and Ferric Reducing/Antioxidant Power assays.

RESULTS

Phytochemical screening of each plant extract evaluated revealed the following major results: (1) No evidence of alkaloids for each of the extraction phases tested was detected in the hexanic, ethanolic, or aqueous phases of Bucida buceras and Phoradendron californicum (oak and mesquite); (2) Analysis of the hexane phase of B. buceras and P. californicum (mesquite) extracts revealed the presence of carotenes, triterpenes/steroids, and lactonic groups; (3) Analysis of the ethanol and aqueous extraction phases for both plants revealed the presence of a diverse range of compounds, including tripterpenes/steroids, lactonics groups, saponins, phenols/tannins, amines and/or amino acids, and flavonoids/anthocyanins; and (4) The highest total phenolic and flavonoid content were observed in P. californicum (oak): 523.886 ± 51.457 µg GAE/mg extract and 409.651 ± 23.091 µg/mg of extract for methanol and aqueous fractions, respectively. The highest flavonoid content was 237.273 ± 21.250 µg PNE/mg extract in the acetone extract of Bucida buceras stems; while the flavonol content (260.685 ± 23.031 µg CE/mg extract) was higher in the ethanol extract of P. californicum (oak). The acetone extract of B. buceras trunk extract showed the highest levels of DPPH radical-scavenging activity (IC50 = 4.136 ± 0.446 µg/mL) and reducing power (4928.392 ± 281.427 µM AAE/mg extract). The highest superoxide radical scavenging activity (IC50) was 55.249 ± 9.829 µg/mL, observed in acetone extracts of B. buceras leaves.

CONCLUSIONS

The results of the present investigation demonstrated the effects of extraction solvent on phenolic and flavonoid content yield-and antioxidant activities by Bucida buceras and Phoradendron californicum. The present investigation further revealed that Bucida buceras exhibited optimal antioxidant capacity when acetone was used as extraction solvent; and the highest yield of phenols and flavonoids were obtained from the P. californicum oak, using methanol and aqueous solvents, respectively.

Investigation of cream and ointment on antimicrobial activity of Mangifera indica extract

Medicinal plants have curative properties due to the presence of various complex chemical substance of different composition, which are found as secondary plant metabolites in one or more parts of these plants. Mangifera indica Linn (MI L.) is a species of mango in the Anacardiaceae family. Phytoconstituents in the seed extracts may be responsible for the antimicrobial activity of the plant. The purpose of the study was to formulate and evaluate the antimicrobial herbal ointment and cream from extracts of the seeds of mango (MI L.) The formulated ointments containing oleaginous-based showed the best formulation compared to the emulsion water in oil type, the ointment and cream bases in different concentration 1%, 5% and 10%. The formulated ointment and cream of MI L. were subjected to evaluation of Uniformity of Weight, measurement of pH, viscosity, Spreadability, Acute skin irritation study, stability study and antimicrobial activity. Our study shows that MI has high potential as an antimicrobial agent when formulated as ointment and creams for topical use. Thus, the present study concludes that the formulated formulations of the MI are safe and efficient carriers, with potent antimicrobial activity.

The chemistry and bioactivity of Southern African flora II: flavonoids, quinones and minor compound classes

This review is intended to highlight the relevance of natural products in drug discovery paying particular attention to those derived from Southern African medicinal plants with diverse biological activities.

Impact of traditional African medicine on drug metabolism and transport

INTRODUCTION

Africa is a continent of rich plant biodiversity with many indigenous plants having a long history of being used for medicinal purposes. A considerable number of patients consult traditional healers in African countries for their primary health-care needs. As Western medicines become more available through governmental programmes to treat diseases such as infections with HIV/AIDS, patients are faced with an increased potential of herb-drug interactions.

AREAS COVERED

Several medicinal herbs indigenous to Africa are discussed in terms of their effects on pharmacokinetics of allopathic drugs through modulation of enzymes and active transporters. Clinically relevant herb-drug interactions obtained from in vivo studies are discussed, with data from in vitro studies also included to ensure a complete review.

EXPERT OPINION

Traditional herbal medicines are often used under a false sense of security because of the perception that it is safe due to its natural origin. The potential for interactions between herbal and allopathic drugs is often neglected. Data on clinically relevant herb-drug interactions from clinical trials can be used to educate health-care workers and patients, contributing to improved therapeutic outcomes.

Evaluation of an ethnomedicinal combination containing Semecarpus kurzii and Hernandia peltata used for the management of inflammation

CONTEXT

Scientific validation of an ethnomedicinal combination consisting of Semecarpus kurzii Engler (Anacardeaceae) leaves (SKL) and Hernandia peltata Meisn (Hernandeaceae) stem-bark (HPB), traditionally used in ailments related to inflammation, pain and fever.

OBJECTIVE

To validate in vivo and in vitro analgesic and antiinflammatory activities of methanol extract of SKL, HPB and their combination.

MATERIALS AND METHODS

Analgesic activity was tested by acetic acid induced writhing reflex and tail flick in Swiss albino mice, while the anti-inflammatory activity was studied in acute, subacute and chronic model on Wistar rats. The vascular permeability, membrane stabilization and protein denaturation were examined to know the possible mode of action.

RESULTS

Significant (p < 0.01) analgesic (78.04% inhibition of writhing) and antiinflammatory (72.54% inhibition of paw edema) activity was observed in combination of SKL and HPB extracts at 250 mg/kg each. The SKL extract alone inhibits acetic acid-induced vascular permeability (64.4%) at 500 mg/kg, while in combination at 250 mg/kg each, the inhibition was 69.49% (p < 0.01). Furthermore, SKL in combination with HPB (0.25 mg/mL each) prevent RBC hemolysis (61.91%) and inhibition of protein denaturation (76.52%)-like indomethacin.

DISCUSSION AND CONCLUSION

The SKL and HPB extract, alone (500 mg/kg) and in combination, (250 mg/kg each) had significant analgesic and antiinflammatory activity, probably by inhibiting the release of certain inflammatory mediators and membrane stabilization, due to the presence of triterpenes, tannins and related phytochemicals in the extracts. Thus, our results demonstrated that this combination provide the scientific rationale of its folk use.

Phytochemical Analysis and Antioxidant Capacity of BM-21, a Bioactive Extract Rich in Polyphenolic Metabolites from the Sea Grass Thalassia testudinum

The aqueous ethanol extract of Thalassia testudinum leaves (BM-21) is now being developed in Cuba as an herbal medicine due to its promising pharmacological properties. Although some interesting biological activities of BM-21 have already been reported, its chemical composition remains mostly unknown. Thus, we now describe the qualitative and quantitative analyzes of BM-21 using standard phytochemical screening techniques, including colorimetric quantification, TLC and HPLC analyses. Phytochemical investigation of BM-21 resulted in the isolation and identification of a new phenolic sulfate ester (1), along with ten previously described phenolic derivatives (2-11), seven of which have never been previously reported from the genus Thalassia. The structures of these compounds were established by analysis of their spectroscopic (1D and 2D NMR) and spectrometric (HRMS) data, as well as by comparison of these with those reported in the literature. Furthermore, BM-21 was found to exhibit strong antioxidant activity in four different free radical scavenging assays (HO•, RO2•, O2-• and DPPH•). Consequently, this is the first study which highlights the phytochemical composition of BM-21 and demonstrates that this product is a rich source of natural antioxidants with potential applications in pharmaceutical, cosmetic and food industries.

Microencapsulation enhances the anti-ulcerogenic properties of Entada africana leaf extract

ETHNOPHARMACOLOGICAL RELEVANCE

The antiulcer potentials of most plants still remain largely unexplored, despite their prospects evidenced by their use as ethnomedicine. Entada africana (Mimosaceae) has been widely used in Africa for the treatment of skin infections, wounds, tonic for stomach troubles and against diphtheria-like throat complaints. The aim of the present study was to evaluate the anti-ulcer properties of Entada africana (EA) ethanol leaf extract and to obtain a novel multiparticulate pharmaceutical formulation (ACE) with it.

MATERIALS AND METHODS

Ethanol or Indomethacin was administered to rats after oral administration of EA (200, 400 and 800 mg extract/kg b.w), ACE (400 and 800 mg/kg bw), cimetidine (100mg/kg bw), misoprostol (40 μg/kg bw) or distilled water/saline (vehicle). Anti ulcer property was evaluated by examining and scoring stomach lesions.

RESULTS

The extract exhibited significant (P<0.01) cytoprotective effect against ethanol and indomethacin induced gastro ulceration. The microcapsules showed enhanced cytoprotective effect against ethanol and indomethacin induced gastro ulceration. Histopathologically, the effects of EA and ACE on mucus epithelia were mild with reduced neutrophil, eosinophil and lymphocytic infiltration in stomach tissues of rats ulcerated with ethanol.

CONCLUSIONS

Our current findings show that EA and its multiparticulate formulation may be a useful preparation in peptic ulcer disease.

Screening of some Tanzanian medicinal plants for their trypanocidal and cytotoxic activities

The objective of the present study was to evaluate in vitro antitrypanosomal and cytotoxic activities of crude extracts of 20 traditionally used medicinal plants of Tanzania. A total of 40 extracts (dichloromethane and methanol) were screened for antiproliferative activity of bloodstream form of T. b. brucei and human leukaemia HL-60 cell. Inhibition of cell proliferation was assessed using resazurin as vital stain. Of the 40 extracts tested, the dichloromethane extract from bark of Warburgia salutaris (Canellaceae) exhibited the most potent antitrypanosomal activity with an IC(50) value of 10.68 microg/ml. A dichloromethane extract from Lannea stuhlmannii (Anacardiaceae) was found to be the most cytotoxic extract against HL-60 (IC(50) = 27.15 microg/ml). Out of the 20 plants tested, 5 plants exhibited trypanocidal activity with IC(50) values below 20 microg/ml. These 5 plants: Entandrophragma bussei (Meliaceae), Securidaca longepedunculata (Polygalaceae), Warburgia salutaris (Canellaceae), Zanha africana (Sapindaceae) and Zanthoxylum chalybeum (Rutaceae) could therefore serve as sources of lead compounds for treatment of trypanosomiasis.

Geraniinic acid derivative from the leaves of Phyllanthus reticulatus

Chemical constituents as well as cytotoxic and insecticidal activity of the crude methanol extract from the leaves of Phyllanthus reticulatus Poir. (Euphorbiaceae) were investigated. (5R*,6R*)-4,6-Dimethoxycarbonyl-5-[2',3',4'-trihydroxy-6'-(methoxycarbonyl) phenyl]-5,6-dihydro-2H-pyran-2-one (1) along with 3,4,3'-tri-O-methylellagic acid, and methyl gallate were isolated from the dichloromethane extract. Determination of their structures was based on spectroscopic analysis. Compound 1 possessed a very weak insecticidal activity against Spodoptera frugiperda (Sf9) with an IC(50) value of 27.27 microg/mL.

Antimicrobial and antimalarial activity of Cussonia species (Araliaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Cussonia species are used in African traditional medicine mainly against pain, inflammation, gastro-intestinal problems, malaria and sexually transmitted diseases.

AIM OF THE STUDY

To summarise ethnomedicinal uses of Cussonia and to find scientific evidence in support of selected main uses.

MATERIALS AND METHODS

Using the minimum inhibitory concentration (MIC) method, leaves of 13 Cussonia species, Schefflera umbellifera and Seemannaralia gerrardii were tested against pathogens associated with diarrhoea (Enterococcus faecalis and Escherichia coli), sexually transmitted infections (Neisseria gonorrhoeae and Trichomonas vaginalis) and general infectious diseases (Staphylococcus aureus and Pseudomonas aeruginosa). Antimalarial sensitivity was studied using Plasmodium falciparum and the [(3)H]-hypoxanthine incorporation assay. Cytotoxic effects on a T-cell leukaemia (Jurkat) cell line were determined using the tetrazolium-based cellular toxicity assay.

RESULTS

Methanolic extracts were active against Pseudomonas aeruginosa (MIC of 1.0-1.5 mg/mL), Trichomonas vaginalis (MIC of 0.8-1.3 mg/mL) and Staphylococcus aureus (Cussonia arborea, 1.8 mg/mL). All samples were active against Neisseria gonorrhoeae (MIC of 0.02-0.7 mg/mL). The methanol extract of Cussonia arborea was the most active against Plasmodium falciparum (13.68 microg/mL) and showed anticancer properties (5.60 microg/mL).

CONCLUSIONS

The traditional use of Cussonia species to treat sexually transmitted diseases and Plasmodium infections appears to have a scientific basis.

Evaluation of anti-inflammatory potential of Chloranthus erectus (Buch.-Ham.) Verd. leaf extract in rats

AIM OF THE STUDY

Chloranthus erectus (Buch.-Ham.) Verdcourt (Chloranthaceae) is a shrub native to tropical and temperate zone of Eastern Himalaya of India and South-East Asia and have traditionally been used as a folklore medicine to treat localised swelling, joint pain, skin inflammation, fever and bodyache. In this study, an attempt has been made to demonstrate the anti-inflammatory activity of methanol extract obtained from Chloranthus erectus leaves (MECEL) in acute, sub-acute and chronic mouse models.

MATERIALS AND METHODS

Inflammation in the hind paw of Wistar albino rat was induced by carrageenan, histamine and serotonin, and tissue granuloma pouch was induced by cotton pellet method. Anti-inflammatory drug-phenylbutazone was used as standard drug for comparison.

RESULTS

In acute carrageenan-induced rat hind paw edema, oral administration of MECEL at 200 mg/kg produced significant inhibition of edema by 38.34% (p < 0.01) while the histamine- and serotonin-induced sub-acute model, the inhibition of paw edema reached 52.54% (p < 0.001) and 25.5% (p < 0.01), respectively. In a 7-day study, MECEL at 20 and 50 mg/kg produced significant suppression of cotton pellet-induced tissue granuloma formation in rats.

CONCLUSIONS

This preliminary study revealed that the methanol extract of Chloranthus erectus exhibited significant anti-inflammatory activity in the tested models, and may provide the scientific rationale for its popular folk medicine as anti-inflammatory agent.

The ethnomedicine of the Haya people of Bugabo ward, Kagera Region, north western Tanzania

BACKGROUND

The Kagera region, in north western Tanzania, is endowed with a strong culture of traditional medicine that is well supported by a rich diversity of medicinal plants. However, most of the plants in this region have not been documented nor evaluated for safety and efficacy. As an initiative in that direction, this study documented the knowledge on medicinal plant use by traditional healers of Bugabo Ward in Bukoba District.

METHODS

Key informants were selected with the help of local government officials and information on their knowledge and use of plants for therapeutic purposes was gathered using a semi-structured interview format.

RESULTS

In this study 94 plant species representing 84 genera and 43 families were found to be commonly used in the treatment of a variety of human ailments. The family Asteraceae had the highest number of species being used as traditional medicines. The study revealed that Malaria is treated using the highest number of different medicinal species (30), followed by skin conditions (19), maternal illnesses and sexually transmitted diseases (14), respiratory diseases (11) and yellow fever, Herpes simplex and peptic ulcers (10). Majority of the species are used to treat less than five different diseases/conditions each and leaves were the most commonly used part, comprising 40% of all the reports on use of plant parts. Trees comprised the most dominant growth form among all plants used for medicinal purposes in the study area.

CONCLUSION

Bugabo Ward has a rich repository of medicinal plants and this reinforces the need for an extensive and comprehensive documentation of medicinal plants in the area and a concomitant evaluation of their biological activity as a basis for developing future medicines.

Recognition and development of traditional medicine in Tanzania

The aim of this paper is to trace developments in Traditional Medicine (TM) and legislation concerning conservation and use of biodiversity in Africa, with Tanzania as a case study. Based on field trips, interviews with different actors, site visits, and literature we explored the history, current status, re-establishment, and development of TM. A summary of laws and regulations concerning forests, access and benefit sharing is presented. During the last decade the Government of Tanzania put forth legislation to address national health needs, traditional knowledge, and the resource base for TM (e.g., practitioners, biodiversity). Our findings indicate that TM is the most common form of health care, and that the HIV pandemic has highlighted the need to work across health sectors. New legislation has facilitated this need. In Tanzania TM is experiencing a renaissance in being formally recognized, integrated into mainstream health care, formal establishment of practitioners, and gaining the interests of different sectors. More studies on bioactivity, safety, domestication, and sustainability of use of medicinal plants are needed. Development of TM can also, other than making a significant contribution to health care and livelihoods, provide income possibilities. It is however yet to be seen if the recent regulations can be made fully operational and implemented.

Medicinal plants used by Tanzanian traditional healers in the management of Candida infections

An ethnomedical survey in Coast, Dar es Salaam, Morogoro and Tanga regions of Tanzania has resulted in the identification of 36 plant species belonging to 21 plant families that are used traditionally for the treatment of Candida infections. Twenty-one plants constituting 58.3% of all collected plants are used to treat of oral candidiasis (Utando) one of the important signs of HIV/AIDS. The knowledge of traditional healers for the treatment of Candida infections has been highly supported by the literature in that 13 (36.1%) out of the 36 plants identified have been proven to be active against Candida albicans and/or other species of Candida. Also, some of the plants were reported to be active against other species of fungi including Cryptococcus neoformans, one of the important pathogenic fungi in HIV/AIDS. It can be seen that ethnomedical information from traditional healers provides a solid lead towards development of new drugs than random screening. The task that remains is to screen extracts prepared from these plants and perform a bioassay-guided fractionation of the active extracts so as to isolate the active compounds from these plants.

Evaluation of plants used for antimalarial treatment by the Maasai of Kenya

Semi-structured interviews with three Maasai herbalists led to the identification and collection of 21 species of plants used to treat malaria. Extracts were evaluated using in vitro antimalarial and cytotoxicity assays. Of the species tested, over half were antiplasmodial (IC50<10 microg/ml), and all but one (Gutenbergia cordifolia Benth.) displayed selectivity for the malaria parasite Plasmodium falciparum as indicated by a lack of cytotoxicity (ED50>20 microg/ml) against cultured KB cells. The results of this preliminary investigation support the traditional knowledge of Maasai herbalists and justify ethnomedical inquiry as a promising method, specifically, in antimalarial therapy, to yield leads for drug discovery.

Phytochemical and pharmacological screening of Sterculiaceae species and isolation of antibacterial compounds

Little previous phytochemical investigation has been conducted on South African Sterculiaceae species used in traditional medicine. In this study, five species, varying in growth type (small herbs, shrubs and large trees) and traditional usage were investigated. The species screened were Cola greenwayi Brenan, Cola natalensis Oliv., Dombeya burgessiae Gerr. ex Harv., Dombeya cymosa Harv. and Hermannia depressa N.E.Br. Extracts were screened for alkaloids, cardiac glycosides, cyanogenic glycosides, saponins and tannins. The probable presence of bufadienolides in the leaf material of Dombeya burgessiae and Dombeya cymosa was determined. Alkaloids, cyanogenic glycosides and saponins were absent in all the plant material investigated. Tannins were detected in the leaf extract of Cola greenwayi and in the leaves, stems and roots of Hermannia depressa. Extracts were screened for anti-inflammatory and antibacterial activity using the cyclooxygenase-1 (COX-1) inhibition assay and the microdilution antibacterial assay. The ethanol and dichloromethane extracts of Cola greenwayi, Dombeya burgessiae and Dombeya cymosa, and the dichloromethane extracts of Hermannia depressa showed the highest levels of COX-1 inhibition. It is possible that the high levels observed may be due to the presence of tannins in some of the extracts. Generally, all the aqueous extracts exhibited low activity. Similarly, no antibacterial activity was observed with the aqueous extracts, although some mild activity was exhibited with some of the ethanol and ethyl acetate extracts. Following the general phytochemical and pharmacological screening, extracts showing antibacterial activity were further purified using bioassay-guided fractionation. Dombeya rotundifolia (Hochst.) Planch., which was screened in a previous study, was also included in the isolation of active compounds. A bioautographic assay, using Staphylococcus aureus, was used to detect the presence of the antibacterial compounds. These were isolated and identified as fatty acids.

Plants used to treat epilepsy by Tanzanian traditional healers

A cross-sectional study performed in Temeke District (Dar es Salaam, Tanzania) showed that 5.5% of the traditional healers have knowledge for the treatment of epilepsy. Of the 100 healers interviewed, 30 (30%) believed that epilepsy was caused by witchcraft, while 19 (19%) thought epilepsy has a genetic origin which can be inherited. Other healers thought epilepsy can be caused by head injury or malaria (24%), and the remaining 27% did not know the cause. Most of the healers (92%) could present an accurate account on the symptoms of the disease, including dizziness, loss of consciousness, abrupt falling down, frothing from the mouth, loss of memory, biting of the tongue, confusion, and restlessness. They showed competence in the treatment of the disease, whereby 60 plants that are commonly used were mentioned. Abrus precatorius L. (Leguminosae), Clausena anisata (Willd.) Oliv. (Rutaceae) and Hoslundia opposita Vahl (Lamiaceae), which are among the plants mentioned, have proven anticonvulsant activity, while a few other species on their list have been reported to be useful in the treatment of epilepsy. Biological testing of these plants, using different models of convulsions is, suggested.

Antioxidant and antimicrobial activities of Onosma argentatum and Rubia peregrina

The n-hexane-dichloromethane (1:1) extract of the roots of Onosma argentatum and the methanol extract (partitioned between water and chloroform, ethyl acetate and n-butanol, respectively), of the underground parts (roots and rhizomes) of Rubia peregrina were tested in vitro for their antioxidant and antimicrobial activities. The highest antioxidant activity (98%) was observed at 0.1% concentration for the roots of O. argentatum. It was 96% at 0.25% concentration on the ethyl acetate fraction of R. peregrina. O. argentatum extract was effective on Staphylococcus aureus, Bacillus subtilis and Escherichia coli. The ethyl acetate and chloroform fractions of R. peregrina were effective on S. aureus and E. coli, respectively. These two species did not have any antifungal activity.

Antinociceptive effects of Zataria multiflora Boiss fractions in mice

Activity-guided fractionation of methanol:chloroform (1:1) extract of Zataria multiflora Boiss was performed in order to investigate the active component(s) responsible for antinociceptive activity. Antinociceptive activity was evaluated using hot-plate and writhing tests. Morphine (10 mg/kg, i.p.) and diclofenac (10 mg/kg, i.p.) were used as positive controls. The methanol-chloroform (1:1) extract of the aerial parts of the plants was prepared and partitioned between methanol-water (9:1) and n-hexane. The more active hydroalcoholic fraction was concentrated and further partitioned between methanol-water (3:2) and chloroform. The hydroalcoholic layer showed a dose-dependent and significant activity compared to morphine and diclofenac. Further fractionation of the hydroalcoholic fraction on silica gel gave six fractions. Three fractions at 100 mg/kg showed activity comparable to those of morphine.

Antifungal activity of some Cuban Zanthoxylum species

Ethanolic extracts of the trunk bark of Zanthoxylum fagara, Z. elephantiasis and Z. martinicense showed activity against different species of fungi. No antibacterial activity was detected.

Antidiabetic activity of Terminalia pallida fruit in alloxan induced diabetic rats

Different doses of ethanolic fraction of fruits of Terminalia pallida were evaluated for hypoglycemic and antihyperglycemic activity in normal and alloxan diabetic rats. The oral administration of ethanolic extract at a dosage of 0.5 g/kg body weight exhibited a significant antihyperglycemic activity in alloxan diabetic rats, whereas in normal rats no hypoglycemic activity was observed.

Antimicrobial activity of Securinega leucopyrus

Extracts of the leaves of Securinega leucopyrus exhibited a broad spectrum of antimicrobial activity.

Effects of Ferula gummosa Boiss. fractions on morphine dependence in mice

Activity-guided fractionation of methanol-chloroform (1:1) extract of Ferula gummosa was carried out to investigate the isolation of the active component(s) responsible for the alleviation of morphine withdrawal syndrome induced by naloxone. Dependence was induced using subcutaneous (s.c.) injections of morphine daily for three days. On day 4, morphine was injected 0.5 h before the interaperitoneal (i.p.) injections of fractions or diazepam (5 mg/kg, i.p.) as positive control. Naloxone was injected (5 mg/kg, s.c.) 2 h after the final dose of morphine. The number of episodes of jumping during 30 min after the injection of naloxone was considered as the intensity of the withdrawal syndrome. The methanol-chloroform (1:1) extract of the aerial parts of plant was prepared and partitioned between water and chloroform. The active chloroform layer was concentrated and partitioned between methanol-water (9:1) and n-hexane. Activity was observed in the hydroalcoholic layer. This layer was concentrated and partitioned further between methanol-water (3:2) and chloroform. The chloroform layer showed a dose-dependent and significant activity. For all fractions the activity was observed at 470 mg/kg. Further purification on silica gel column chromatography gave a pure compound, which was 10 times as effective as the crude extract. The results of this study indicated that the plant extract contained component(s) that could be useful for the alleviation of morphine withdrawal syndrome.

In vitro antiplasmodial activity and cytotoxicity of ethnobotanically selected South African plants

The resistance of Plasmodium spp. to currently used drugs has become a serious problem and efforts are being directed in obtaining new drugs with different structural features. One option favoured is the search for new plant derived antimalarial drugs. Bark and leaves of 20 extracts from 14 South African plant species were tested for in vitro antiplasmodial activity by means of the flow cytometric test. The most active extract of each species giving more than 70% inhibition at 50 microg/ml was selected for determination of IC(50) values. Two extracts had IC(50) values below 2 microg/ml, another seven had IC(50) values between 2 and 5 microg/ml while one had an IC(50) of 10.1 microg/ml. Chloroquine had an IC(50) of 0.043 microg/ml. Cytotoxicities of the five most active extracts at 50 microg/ml were determined with the monkey kidney cell toxicity test and the ID(50) values ranged between 35 and 100 microg/ml.

Antimicrobial activity of Newtonia hildebrandtii

Successive petroleum ether, dichloromethane and methanol extracts of Newtonia hildebrandtii stem bark were tested in vitro for their antifungal and antibacterial activity. The methanol extract was found to be the most effective against the tested pathogens.

Antinociceptive effect of Elaeagnus angustifolia fruit seeds in mice

The antinociceptive effect of different Elaeagnus angustifolia fruit seed extractives was studied in mice using hot-plate and writhing tests. Following intraperitoneal injection, the decoction (EaDE), the ethanol extract (EaEE), the aqueous and n-butanol fractions (EaAF, and EaBF, respectively) of a polyphenolic fraction, and two flavonoid-enriched fractions of EaBF (EaBCF1 and EaBCF2) showed significant antinociceptive activity in both tests, markedly and dose-dependently increasing the pain threshold.

Plants used against cancer - an extension of the work of Jonathan Hartwell

A survey of plants used ethnomedically against cancer was undertaken, using the NAPRALERT database currently maintained by the Program for Collaborative Research in the Pharmaceutical Sciences, College of Pharmacy, University of Illinois-Chicago. We report over 350 species which are reported to be used against cancer and not cited in the work of Jonathan Hartwell, "Plants used against cancer: a survey", including previously unrepresented genera and families.