Natural products as drugs

Phytochemical Profiles and Biological Activities of Frankenia Species: A Review

The relatively small Frankeniaceae family is represented by halophyte plants, growing in arid and semi-arid climates in saline, alkaline or calcareous soils. Due to their living conditions, they usually produce a large diversity of compounds, which often exhibit bioactivities. Some species of this genus have long been used as traditional herbal medicines to treat dysentery, diarrhea, gonorrhea, vaginal leucorrhea, respiratory diseases and wounds. To date, several studies on either phytochemical or pharmacological aspects, or both, have revealed that this genus is a rich source of diverse and novel bioactive chemicals, including phenolics, flavonoids, alkaloids and fatty acids. This review describes all the reported chemical profiles of Frankenia species, as well as the corresponding biological properties, when available. The aim of this review is to show the potential of these plants for various applications, especially therapeutic ones.

The African cherry: A review of the botany, traditional uses, phytochemistry, and biological activities of Prunus africana (Hook.f.) Kalkman

ETHNOPHARMACOLOGICAL RELEVANCE

Prunus africana (Hook.f.) Kalkman (Rosaceae), commonly known as "Pygeum" or "African cherry", occurs in mainland montane forests scattered across sub-Saharan Africa, Madagascar, and some surrounding islands. Traditionally, decoctions of the stem-bark are taken orally for the treatment of a wide variety of conditions, such as benign prostatic hyperplasia (BPH), stomach ache, chest pain, malaria, heart conditions, and gonorrhoea, as well as urinary and kidney diseases. The timber is used to make axe handles and for other household needs. The dense wood is also sawn for timber.

AIM

The fragmented information available on the ethnobotany, phytochemistry, and biological activities of the medicinally important P. africana was collated, organised, and analysed in this review, to highlight knowledge voids that can be addressed through future research.

MATERIALS AND METHODS

A bibliometric analysis of research output on P. africana was conducted on literature retrieved, using the Scopus® database. The trend in the publications over time was assessed and a network analysis of collaborations between countries and authors was carried out. Furthermore, a detailed review of the literature over the period 1971 to 2021, acquired through Scopus, ScienceDirect, SciFinder, Pubmed, Scirp, DOAJ and Google Scholar, was conducted. All relevant abstracts, full-text articles and various book chapters on the botanical and ethnopharmacological aspects of P. africana, written in English and German, were consulted.

RESULTS

A total of 455 documents published from 1971 to 2021, were retrieved using the Scopus search. Analysis of the data showed that the majority of these documents were original research articles, followed by reviews and lastly a miscellaneous group comprising conference papers, book chapters, short surveys, editorials and letters. Data were analysed for annual output and areas of intense research focus, and countries with high research output, productive institutions and authors, and collaborative networks were identified. Prunus africana is reported to exhibit anti-inflammatory, analgesic, antimicrobial, anti-oxidant, antiviral, antimutagenic, anti-asthmatic, anti-androgenic, antiproliferative and apoptotic activities amongst others. Phytosterols and other secondary metabolites such as phenols, triterpenes, fatty acids, and linear alcohols have been the focus of phytochemical investigations. The biological activity has largely been ascribed to the phytosterols (mainly 3-β-sitosterol, 3-β-sitostenone, and 3-β-sitosterol-glucoside), which inhibit the production of prostaglandins in the prostate, thereby suppressing the inflammatory symptoms associated with BPH and chronic prostatitis.

CONCLUSIONS

Many of the ethnobotanical assertions for the biological activity of P. africana have been confirmed through in vitro and in vivo studies. However, a disparity exists between the biological activity of the whole extract and that of single compounds isolated from the extract, which were reported to be less effective. This finding suggests that a different approach to biological activity studies should be encouraged that takes all secondary metabolites present into consideration. A robust technique, such as multivariate biochemometric data analysis, which allows for a holistic intervention to study the biological activity of a species is suggested. Furthermore, there is a need to develop rapid and efficient quality control methods for both raw materials and products to replace the time-consuming and laborious methods currently in use.

Ethanol extract of Bergenia ciliata (Haw.) Sternb. (rhizome) impedes the propagation of the malaria parasite

ETHNOPHARMACOLOGICAL RELEVANCE

The increasing resistant cases even against artemisinin-based combination therapy have necessitated the need to develop new antimalarials. Phytomedicinal therapy is a benchmark for malaria in the Himalayan region. As the dialect and traditional variations have been seen along with this, usage of medicinal plant, its portion (shoot and root system) and mode of preparation also varies. There is no scientific evidence available for illustrating the antiplasmodial activity of the rhizomes of Bergenia ciliata (Saxifragaceae), which is known to be an antipyretic (fever akin to malaria), hepato-protective, and also for spleen enlargement.

AIM OF THE STUDY

The present study evaluates the antimalarial activity of ethanol extract of B. ciliata rhizomes (EREBC).

MATERIALS AND METHODS

HPTLC was performed to identify and quantify three marker compounds in EREBC. The in vitro antimalarial activity was evaluated by schizont maturation inhibition assay. MTT assay was employed to test the cytotoxicity of EREBC. Peter's 4-day test and Peters method was employed to discern the suppressive and preventive activity of the extract respectively.

RESULTS

HPTLC analysis revealed the presence of bergenin, epicatechin and gallic acid in the extract. EREBC exhibited considerable inhibition (IC₅₀ < 5 μg/mL) of schizont maturation of both RKL-9 and MRC-2 strains of P. falciparum. EREBC was non-toxic to both HeLa cells and normal dermal fibroblasts (CC₅₀ > 1000 μg/mL). The selectivity index was > 200 for both strains. Acute toxicity of EREBC was > 4 g/kg. EREBC exhibited considerable in vivo suppressive activity with 96.48% inhibition at 500 mg/kg in comparison to chloroquine (96.08%). The ED₅₀ of the extract was < 50 mg/kg. No mortality was evident in mice administered with different doses of EREBC (50-500 mg/kg) throughout the follow up period of 28 days. EREBC exhibited safety to liver and kidney function of mice as observed from biochemical analysis.

CONCLUSION

Overall, the study illustrates the marked efficacy and potential of EREBC as an antimalarial agent with bergenin, epicatechin and gallic acid its major constituents, which played a pivotal role in the generation of the immune response.

Antiproliferative Effects of Matricine in Gemcitabine-Resistant Human Pancreatic Carcinoma Cells Are Mediated via Mitochondrial-Mediated Apoptosis, Inhibition of Cell Migration, Invasion Suppression, and Mammalian Target of Rapamycin (mTOR)-TOR/PI3K/AKT Signalling Pathway

BACKGROUND Pancreatic cancer is a major cause of mortality worldwide. Inefficient drugs, their adverse effects, and the development of drug resistance make it difficult to curb the growing incidence of pancreatic cancer. Against this backdrop, the development new drug regimens with no or negligible adverse effects is imperative. We assessed the anticancer effects of a plant-derived sesquiterpene - matricine - against capan-2 pancreatic cancer cells. MATERIAL AND METHODS Cell viability was determined by MTT assay. AO/EB, DAPI, and annexin V/PI staining were used to detect apoptosis. Transwell assays were used for monitoring of cell migration and invasion. Immunoblotting was used to examine the expression of proteins. RESULTS The results showed that matricine halted the proliferation of capan-2 cells, with minimal toxic effects on normal pancreatic cells. The anticancer effects were due to the induction of apoptotic cell death, which was allied with activation of caspases 3 and 9, upregulation of Bax, and downregulation of Bcl-2. Moreover, matricine suppressed the migration and invasive abilities of pancreatic cancer cells at IC50. We also assessed the effects of matricine on the mTOR/PI3K/AKT signalling pathway. We found that matricine efficiently blocked this pathway, suggesting the anticancer potential of matricine. CONCLUSIONS Matricine induced antiproliferative effects in capan-2 human pancreatic cancer cells through inducing apoptosis, caspase activation, inhibition of cell migration and invasion, and blocking the mTOR/PI3K/AKT signalling pathway.

Anti-Plasmodium falciparum Activity of Extracts from 10 Cameroonian Medicinal Plants

Background: In the midst of transient victories by way of insecticides against mosquitoes or drugs against malaria, the most serious form of malaria, caused by Plasmodium falciparum, continues to be a major public health problem. The emergence of drug-resistant malaria parasites facilitated by fake medications or the use of single drugs has worsened the situation, thereby emphasizing the need for a continued search for potent, safe, and affordable new antimalarial treatments. In line with this need, we have investigated the antiplasmodial activity of 66 different extracts prepared from 10 different medicinal plants that are native to Cameroon. Methods: Extracts were evaluated for their capacity to inhibit the growth of the chloroquine-sensitive (Pf3D7) and resistant (PfINDO) strains of P. falciparum using the SYBR green fluorescence method. The cytotoxicity of promising extracts against human embryonic kidney cells (HEK293T) mammalian cells was assessed by MTT assay. Results: The antiplasmodial activity (50% inhibitory concentration, IC50) of plant extracts ranged from 1.90 to >100 μg/mL against the two strains. Six extracts exhibited good activity against both Pf3D7 and PfINDO strains, including cold water, water decoction, and ethyl acetate extracts of leaves of Drypetes principum (Müll.Arg.) Hutch. (IC503D7/INDO = 4.91/6.64 μg/mL, 5.49/5.98 μg/mL, and 6.49/7.10 μg/mL respectively), water decoction extract of leaves of Terminalia catappa L. (IC503D7/INDO = 6.41/8.10 μg/mL), and water decoction extracts of leaves and bark of Terminalia mantaly H.Perrier (IC503D7/INDO = 2.49/1.90 μg/mL and 3.70/2.80 μg/mL respectively). These promising extracts showed no cytotoxicity against HEK293T up to 200 μg/mL, giving selectivity indices (SIs) in the range of >31.20⁻80.32. Conclusions: While providing credence to the use of D. principum, T. catappa, and T. mantaly in the traditional treatment of malaria, the results achieved set the stage for isolation and identification of active principles and ancillary molecules that may provide us with new drugs or drug combinations to fight against drug-resistant malaria.

Role of Vital Trace Elements in Nanocurcumin-Centered Formulation: A Novel Approach to Resuscitate the Immune System

The present paper described the immunomodulatory potential of novel nanocurcumin-based formulation enriched with trace elements and vitamins on cyclophosphamide-induced immunosuppression in rat model. Major immune-related assays were monitored such as hemagglutination assay, delayed-type hypersensitivity (DTH) reaction, cellular immune response, IgG, IgE, IgM, cerebrospinal fluid biomarkers, hematological study, antioxidant profile, and lipid biomarkers. Chemical characterization of novel formulation showed retention time (R _t ) 18.98 of curcumin, while LC-MS data revealed the presence of the curcumin mass at m/z 369.01 [M + H]⁺ (calculated for C₂₁H₂₁O₆⁺, 369.13). This novel formulation exhibited significantly (p ≤ 0.001) increased primary and secondary antibody titer by 72.41% and 33.25%, respectively, while DTH response being improved by 87.50% (p ≤ 0.01). However, CD4⁺, CD8⁺, and CD28⁺ counts were significantly (p ≤ 0.05) increased by 76.46%, 68.21%, and 19.29%, respectively, while the concentrations of IgE, IgM, and IgG were significantly (p ≤ 0.05) increased by 40%, 28.43%, and 38.75%, respectively. CSF biomarkers analysis showed a decreased level of corticosterone, dopamine, serotonin, and tau protein by 29.38%, 51.73%, 29.93%, and 4.87%, respectively. Antioxidant enzymes such as CAT, GPx, and SOD were increased by 43.74%, 49.00%, and 40.84%, respectively, and non-enzymatic component, GSH, was increased by 55.52%. Similarly, free radical LPO was significantly (p ≤ 0.05) decreased by 40.37%, and acute inflammatory marker, MPO concentration, was reduced by 31.14%, compared with the disease control group. In addition, supportive hematology and lipid profile analysis showed promising results with improved overall animal profile. Thus, trace elements in novel formulation can be used in the various pharmacological activities and as dietary supplement due to its wide properties.

Polyphyllin G exhibits antimicrobial activity and exerts anticancer effects on human oral cancer OECM-1 cells by triggering G2/M cell cycle arrest by inactivating cdc25C-cdc2

Plant natural products have long been considered to be important sources of bioactive molecules. A large number of antimicrobial and anticancer agents have been isolated form plants. In the present study we evaluated the antimicrobial and anticancer activity of a plant derived secondery metabolite, Polyphyllin G. The results of antibacterial assays showed that Polyphyllin G prevented the growth of both Gram-positive and Gram-negative bacteria with minimum inhibitory concentrations (MICs) ranging from 13.1 to 78 μg/ml. Antifungal activity measured as inhibition of mycelium growth ranged between 38.32 and 56.50%. Further Polyphyllin G was also evaluated against a panel of cancer cell lines. The IC₅₀ of Polyphyllin G ranged from 10 to 65 μM. However the IC₅₀ of Polyphyllin G was found to be comparatively high (120 μM) against the normal FR2 cancer cell line. The lowest IC₅₀ of 10 μM was found against the oral cancer cell line OECM-1. Therefore further studies were carried out on this cell line only. Our results indicated that Polyphyllin G induced cell arrest in oral cancer OECM-1 cells by inactivation of cdc25C-cdc22 via ATM-Chk 1/2 stimulation. Therefore, we propose that Polyphyllin G might prove a lead molecule in the management of oral cancers and at the same time may prevent the growth of opportunistic microbes.

Physicochemical/photophysical characterization and angiogenic properties of Curcuma longa essential oil

ABSTRACT This study analyzed the physicochemical and photophysical properties of essential oil of Curcuma longa and its angiogenic potential. The results showed that curcumin is the main fluorescent component present in the oil, although the amount is relatively small. The experimental chorioallantoic membrane model was used to evaluate angiogenic activity, showing a significant increase in the vascular network of Curcuma longa and positive control groups when compared to the neutral and inhibitor controls (P <0.05), but no significant difference was found between Curcuma longa essential oil and the positive control (P >0.05). Histological analysis showed extensive neovascularization, hyperemia and inflammation in the positive control group and Curcuma longa when compared to other controls (P <0.05), characteristic factors of the angiogenesis process. In conclusion, Curcuma longa oil showed considerable proangiogenic activity and could be a potential compound in medical applications.

Antimicrobial activity and probable mechanisms of action of medicinal plants of Kenya: Withania somnifera, Warbugia ugandensis, Prunus africana and Plectrunthus barbatus

Withania somnifera, Warbugia ugandensis, Prunus africana and Plectrunthus barbatus are used traditionally in Kenya for treatment of microbial infections and cancer. Information on their use is available, but scientific data on their bioactivity, safety and mechanisms of action is still scanty. A study was conducted on the effect of organic extracts of these plants on both bacterial and fungal strains, and their mechanisms of action. Extracts were evaluated through the disc diffusion assay. Bacteria and yeast test strains were cultured on Mueller-Hinton agar and on Sabouraud dextrose agar for the filamentous fungi. A 0.5 McFarland standard suspension was prepared. Sterile paper discs 6 mm in diameter impregnated with 10 µl of the test extract (100 mg/ml) were aseptically placed onto the surface of the inoculated media. Chloramphenicol (30 µg) and fluconazole (25 µg) were used as standards. Discs impregnated with dissolution medium were used as controls. Activity of the extracts was expressed according to zone of inhibition diameter. MIC was determined at 0.78-100 mg/ml. Safety studies were carried using Cell Counting Kit 8 cell proliferation assay protocol. To evaluate extracts mechanisms of action, IEC-6 cells and RT-PCR technique was employed in vitro to evaluate Interleukin 7 cytokine. Investigated plants extracts have both bactericidal and fungicidal activity. W. ugandensis is cytotoxic at IC50<50 µg/ml with MIC values of less than 0.78 mg/ml. Prunus africana shuts down expression of IL 7 mRNA at 50 µg/ml. W. somnifera has the best antimicrobial (1.5625 mg/ml), immunopotentiation (2 times IL 7 mRNA expression) and safety level (IC50>200 µg/ml). Fractions from W. ugandensis and W. somnifera too demonstrated antimicrobial activity. Mechanisms of action can largely be attributed to cytotoxicity, Gene silencing and immunopotentiation. Use of medicinal plants in traditional medicine has been justified and possible mechanisms of action demonstrated. Studies to isolate and characterize the bioactive constituents continue.

Medicinal plants: a source of anti-parasitic secondary metabolites

This review summarizes human infections caused by endoparasites, including protozoa, nematodes, trematodes, and cestodes, which affect more than 30% of the human population, and medicinal plants of potential use in their treatment. Because vaccinations do not work in most instances and the parasites have sometimes become resistant to the available synthetic therapeutics, it is important to search for alternative sources of anti-parasitic drugs. Plants produce a high diversity of secondary metabolites with interesting biological activities, such as cytotoxic, anti-parasitic and anti-microbial properties. These drugs often interfere with central targets in parasites, such as DNA (intercalation, alkylation), membrane integrity, microtubules and neuronal signal transduction. Plant extracts and isolated secondary metabolites which can inhibit protozoan parasites, such as Plasmodium, Trypanosoma, Leishmania, Trichomonas and intestinal worms are discussed. The identified plants and compounds offer a chance to develop new drugs against parasitic diseases. Most of them need to be tested in more detail, especially in animal models and if successful, in clinical trials.

Contribution to in vitro screening of Egyptian plants for schistosomicidal activity

CONTEXT

This study is a continuation of our previous work in which a bioassay screening of 346 methanol extracts from 281 Egyptian plant species was carried out for in vitro schistosomicidal activity.

OBJECTIVE

Another 309 methanol extracts from 278 plant species were subjected to the bioassay screening using the same technique on viable Schistosoma mansoni Sambon (Schistosomatidae) mature worms in specialized culture medium (Roswell Park Memorial Institute medium 1640) in a trial to discover a source for a schistosomiasis drug from Egyptian flora.

MATERIAL AND METHODS

The methanol plant extracts were tested in vitro against viable S. mansoni mature worms in culture medium. Viability of worms was examined after exposure to 100 μg/ml of the extract in the medium for 24 h. Negative (dimethyl sulfoxide) and positive (praziquantel) controls were simultaneously used. Extracts showing schistosomicidal activity were further subjected to determination of their (Lethal concentration) LC₅₀ and LC₉₀ values.

RESULTS

Confirmed in vitro antischistosomal activity was found in 42 extracts. Of these, 14 plant species possessed considerably high antischistosomal activity (LC₅₀ ≤ 15 µg/ml), viz. Callistemon viminalis (Soland. Ex Gaertn) Cheel, C. rigidus R.Br., C. speciosus (Sims.) DC, C. citrinus Stapf, Eucalyptus citriodora Hook, E. rostrata Dehnh., Eugenia edulis Vell, E. javanica Lam syn. Syzygium samarangense (Blume) Merril, Melaleuca leucadendron (L.) L., M. stypheloides Sm. (all belong to Myrtaceae), Cryptostegia grandiflora R.Br. (Asclepiadaceae), Zilla spinosa (L.) Prantl (Cruciferae), Ficus trijuja L. (Moraceae) and Fagonia mollis Delile (Zygophylacae).

DISCUSSION AND CONCLUSION

These species may represent additional natural sources of bioactive material that deserve further investigation for drug discovery against schistosomiasis.

Traditional antimalarial phytotherapy remedies used by the South Coast community, Kenya

AIM OF THE STUDY

This study was conducted to document herbal medicines used in the treatment of malaria as well as the existing knowledge, attitudes and practices related to malaria recognition, control and treatment in South Coast, Kenya.

METHODS

Data was collected using semistructured questionnaires and interviews. A focused group discussion held with the community members, one in each of the study villages supplemented the interview and questionnaire survey.

RESULTS

The respondents were found to have a good understanding of malaria and could distinguish it from other fever types. They were also aware that malaria was spread by mosquitoes. Malaria prevalence was high, and affected individuals an average of four times a year. Community members avoided mosquito bites by using mosquito nets, clearing bushes around their homesteads and burning plant parts to generate smoke. They prevented and treated malaria by taking decoctions or concoctions of traditional herbal remedies. Forty plant species in thirty-five genera distributed in twenty-four families were used as antimalarials in the study area. Five plant species, namely; Heeria insignis Del. (Anacardiaceae), Rottboelia exaltata L.F (Gramineae), Pentanisia ouranogyne S. Moore (Rubiaceae), Agathisanthenum globosum (A. Rich) Hiern (Rubiaceae), and Grewia trichocarpa Hochst ex A. Rich (Tiliaceae) are documented for the first time in South Coast, Kenya, for the treatment of malaria.

CONCLUSIONS

The plants documented in the current study are a potential source for new bioactive compounds of therapeutic value in malaria treatment. The results provide data for further pharmacological and toxicological studies and development of commercial antimalarial phytotherapy products.

Antimalarial compounds isolated from plants used in traditional medicine

Objectives

This review covers the compounds with antiplasmodial activity isolated from plants published from 2005 to the end of 2008, organized according to their phytochemical classes. Details are given for substances with IC50 values ≤ 11 μM.

Key findings

Malaria is a major parasitic disease in many tropical and subtropical regions and is responsible for more than 1 million deaths each year in Africa. The rapid spread of resistance encourages the search for new active compounds. Nature and particularly plants used in traditional medicine are a potential source of new antimalarial drugs as they contain molecules with a great variety of structures and pharmacological activities.

Summary

A large number of antimalarial compounds with a wide variety of structures have been isolated from plants and can play a role in the development of new antimalarial drugs. Ethnopharmacological approaches appear to be a promising way to find plant metabolites that could be used as templates for designing new derivatives with improved properties.

Traditional antimalarial phytotherapy remedies in herbal markets in southern Ghana

ETHNOPHARMACOLOGICAL RELEVANCE

Although traditional antimalarial plant remedies in herbal markets are a very important component of the health care system in Ghana this has not been previously studied to allow for the formulation of effective strategy for malaria control in Ghana.

AIM OF STUDY

The main objective of the present study was to collect and analyse data on the antimalarial plant remedies in herbal markets in southern Ghana.

MATERIALS AND METHODS

Herborists were interviewed using a validated questionnaire and species of plants were identified using a combination of field photo guides, local names and voucher specimens.

RESULTS

A total of 71 herborists (95.8% female) were interviewed. There were potential correlations between different parameters and variables such as ethnic groups, type of vendor and age-groups. The study revealed 29 species of plants belonging to 22 families being sold for the treatment of malaria. The detailed use of these plants is documented. The most frequently mentioned species of plants were Morinda lucida Benth., Indigofera sp. and Nauclea latifolia Sm. The majority (82.8%) of the plant materials were sold in the dried state and 6.9% were sold in fresh state. About 76.2% of the herbal remedies were sold throughout the year while 23.8% were scarce in the dry season. The cost of treatment of malaria using the herbal remedies ranged from 1 to 2 United States Dollars (USD).

CONCLUSION

Standardization of names and authentication of plant materials using organoleptic, phytochemical and DNA barcoding techniques as well as further research on efficacy, safety and dosage prescriptions for both fresh and dried plant materials being sold for the treatment of malaria in southern Ghana are needed.

Current status of malaria chemotherapy and the role of pharmacology in antimalarial drug research and development

Antimalarial drugs have played a mainstream role in controlling the spread of malaria through the treatment of patients infected with the plasmodial parasites and controlling its transmissibility. The inadequate armory of drugs in widespread use for the treatment of malaria, development of strains resistant to currently used antimalarials, and the lack of affordable new drugs are the limiting factors in the fight against malaria. In addition, other problems with some existing agents include unfavorable pharmacokinetic properties and adverse effects/toxicity. These factors underscore the continuing need of research for new classes of antimalarial agents, and a re-examination of the existing antimalarial drugs that may be effective against resistant strains. In recent years, major advances have been made in the pharmacology of several antimalarial drugs both in pharmacokinetics and pharmacodynamics aspects. These include the design, development, and optimization of appropriate dosage regimens of antimalarials, basic knowledge in metabolic pathways of key antimalarials, as well as the elucidation of mechanisms of action and resistance of antimalarials. Pharmacologists have been working in close collaboration with scientists in other disciplines of science/biomedical sciences for more understanding on the biology of the parasite, host, in order to exploit rational design of drugs. Multiple general approaches to the identification of new antimalarials are being pursued at this time. All should be implemented in parallel with focus on the rational development of new agents directed against newly identified parasite targets. With major advances in our understanding of malaria parasite biology coupled with the completion of the malaria genome, has presented exciting opportunities for target-based antimalarial drug discovery.

Traditional management of tuberculosis in Ogun State of Nigeria: the practice and ethnobotanical survey

An ethnobotanical survey was conducted on plants used traditionally for the management of tuberculosis in five local government areas of Ogun State, Nigeria, in a bid to document herbs used in the management of tuberculosis with the aim of identifying possible drug lead from the phytomedicine of these communities. A semi-structured questionnaire was used to obtain the required information on the use of herbal remedies for the management. A total of 50 respondents made up of herbalists (40.0%), herb sellers (52.0%) and traditional medicine practitioners (8.0%) were interviewed in the study. The dominant age of respondents was in the range of 21-40 years (72.0%). Duration of treatment of tuberculosis with herbs was between 2-12 weeks. A total of 36 plants belonging to 20 families were proffered for the management of tuberculosis. Eighty four percent (42%) of the 50 respondents interviewed said that their clients observed no side effects and that the herbs were either available in the forest or purchased from the markets. Cola acumminata (fruit), Garcinia kola (leaf), Vitallaria parodoxa (oil), Costus afer (stem), Pycnanthus angolensis (stem bark) and Aframomum melegueta (fruit) were the most frequently mentioned herbs. The ethnomedicines of the studied areas of Ogun State, Nigeria seem to have a high potential as a source of drug discovery of anti-tuberculosis. This is of utmost importance because people living with human immunodeficiency virus (HIV) are susceptible to tuberculosis.

Antimalarial activity of some plants traditionally used in treatment of malaria in Kwale district of Kenya

Methanolic and water extracts of five medicinal plant species used for treatment of malaria in traditional/cultural health systems of Kwale people in Kenya were tested for antimalarial activity against Plasmodium falciparum and Plasmodium berghei, respectively and for their cytotoxic effects. The most active extracts (IC(50)<10 microg/ml) screened against chloroquine (CQ) sensitive (D6) and resistant (W2) P. falciparum clones, were the water and methanol extracts of Maytenus undata (Thunb.) Blakelock (Celasteraceae), methanol extracts of Flueggea virosa (Willd.) Voigt (Euphorbiaceae), Maytenus putterlickioides (Loes.) Excell and Mendoca (Celastraceae), and Warburgia stuhlmannii Engl. (Canellaceae). These extracts showed various cytotoxic levels on Vero E6 cells with the water extract of M. undata exhibiting least cytotoxicity. At least one of the extracts of the plant species exhibited a high chemo suppression of parasitaemia >70% in a murine model of P. berghei infected mice. These results indicate that there is potential for isolation of a lead compound from the extracts of the five plants. W. stuhlmannii and M. putterlickioides have not been reported before for antiplasmodial activity.

Anti-malarial activity of some xanthones isolated from the roots of Andrographis paniculata

Four xanthones were isolated from the roots of Andrographis paniculata using a combination of column and thin-layer chromatographic methods. They were characterized as (i) 1,8-di-hydroxy-3,7-dimethoxy-xanthone, (ii) 4,8-dihydroxy-2,7-dimethoxy-xanthone, (iii) 1,2-dihydroxy-6,8-dimethoxy-xanthone and (iv) 3,7,8-trimethoxy-1-hydroxy xanthone by IR, MS and NMR spectroscopic methods. In vitro study revealed that compound 1,2-dihydroxy-6,8-dimethoxy-xanthone possessed substantial anti-plasmodial activity against Plasmodium falciparum with its IC(50) value of 4 microg ml(-1). Xanthones bearing hydroxyl group at 2 position demonstrated most potent activity while xanthones with hydroxyl group at 1,4 or 8 position possessed very low activity. In vivo anti-malarial sensitivity test of this compound on Swiss Albino mice with Plasmodium berghei infection using Peters' 4-day test gave substantial reduction (62%) in parasitaemia after treating the mice with 30 mg kg(-1) dose. In vitro cytotoxicity against mammalian cells revealed that 1,2-dihydroxy-6,8-dimethoxy-xanthone is non-cytotoxic with its IC(50) > 32 microg ml(-1).

Ethnobotanical survey and in vitro antiplasmodial activity of plants used in traditional medicine in Burkina Faso

In Burkina Faso, most people in particular, in rural areas, use traditional medicine and medicinal plants to treat usual diseases. In the course of new antimalarial compounds, an ethnobotanical survey has been conducted in different regions. Seven plants, often cited by traditional practitioners and not chemically investigated, have been selected for an antiplasmodial screening: Pavetta crassipes (K. Schum), Acanthospermum hispidum (DC), Terminalia macroptera (Guill. et Perr), Cassia siamea (Lam), Ficus sycomorus (L), Fadogia agrestis (Schweinf. Ex Hiern) and Crossopteryx febrifuga (AFZ. Ex G. Don) Benth. Basic, chloroform, methanol, water-methanol and aqueous crude extracts have been prepared and tested on Plasmodium falciparum chloroquine-resistant W2 strain. A significant activity has been observed with alkaloid extract of P. crassipes (IC(50)<4 microg/ml), of A. hispidum, C. febrifuga, and F. agrestis (4<IC(50)<10 microg/ml). The best result is obtained with aqueous extract of T. macroptera with an IC(50)=1 microg/ml. These results confirm the traditional use of these plants.

Cultural categorization of febrile illnesses in correlation with herbal remedies used for treatment in Southwestern Nigeria

The ethnographic study was conducted in two communities in Oyo State in Southwestern Nigeria. The study sites consisted of a rural and an urban local government area located in the tropical rain forest zone of Nigeria. The study was designed to obtain information on febrile illnesses and herbal remedies for treatment with the aim of identifying potential antimalarial drugs. The study revealed that fever is a general term for describing illnesses associated with elevated body temperature. The indigenous Yoruba ethnic population has categorized fever based on symptoms and causes. The present communication is the result of focus group discussion and semi-structured questionnaire administered to traditional healers, herb sellers, elders and mothers. This was on types of fevers, symptoms and causes of febrile illnesses. The investigation also included use of traditional herbs in the prevention and treatment of the illnesses in the two communities.A total of 514 respondents were interviewed. This was made up of 266 (51.8%) from Atiba local government area (LGA), an urban centre while 248 (48.2%) respondents were interviewed from Itesiwaju LGA, a rural community. The LGAs are located in Oyo State of Nigeria. The respondents proffered 12 types of febrile illnesses in a multiple response answering system in Yoruba language. The most common ones (direct translation into English) were: yellow fever (39.1%), typhoid (34.8%), ordinary (28.8%), rainy season (20.8%) and headache (10.5%) fevers, respectively. Perceived causes of each of the febrile illnesses included stress, mosquito bites, unclean water, rains and over exposure to the sun. Methods of fever prevention were mainly with the use of herbal decoctions, powdered herbs, orthodox medications and maintenance of proper hygiene. Of a total of 112 different herbal remedies used in the treatment of the febrile illnesses compiled from the study, 25 recipes are presented. Recipes consisted of 2-7 ingredients. Oral decoctions (84%), oral powders (63%), use as soaps and creams (40%) in a multiple response system, were the most prevalent routes of administration of prepared herbs used in the treatment of the fevers. Boiling in water or alcohol was the most common method used in the preparation of the remedies. The four most frequently mentioned (multiple response system) plants in the Southwest ethnobotany for fevers were Azadirachta indica (87.5%), Mangifera indica (75.0%), Morinda lucida (68.8%) and Citrus medica (68.8%).

Biological activities of Curcuma longa L

There are several data in the literature indicating a great variety of pharmacological activities of Curcuma longa L. (Zingiberaceae), which exhibit anti-inflammatory, anti-human immunodeficiency virus, anti-bacteria, antioxidant effects and nematocidal activities. Curcumin is a major component in Curcuma longa L., being responsible for its biological actions. Other extracts of this plant has been showing potency too. In vitro, curcumin exhibits anti-parasitic, antispasmodic, anti-inflammatory and gastrointestinal effects; and also inhibits carcinogenesis and cancer growth. In vivo, there are experiments showing the anti-parasitic, anti-inflammatory potency of curcumin and extracts of C. longa L. by parenteral and oral application in animal models. In this present work we make an overview of the pharmacological activities of C. longa L., showing its importance.

Microbiological screening of Indian medicinal plants with special reference to enteropathogens

The World Health Organisation (WHO) has recommended that all member states actively promote native medicines in their country. Ten Indian medicinal plants were screened for antibacterial activity specific to enteropathogens. Diffusion and dilution methods were used to measure the antibacterial activity. Allium sativum, Camellia sinensis, and Chamaesyce hirta showed higher activity when compared to the rest. They had a minimum bactericidal concentration (MBC) of < 100 micrograms/ml and gave inhibition zones of more than 2 cm. Among the pathogens studied, Vibrio cholerae and Shigella flexneri were found to be highly susceptible to the plant extracts.

The role of plant-derived drugs and herbal medicines in healthcare

Many of our present medicines are derived directly or indirectly from higher plants. While several classic plant drugs have lost much ground to synthetic competitors, others have gained a new investigational or therapeutical status in recent years. In addition, a number of novel plant-derived substances have entered into Western drug markets. Clinical plant-based research has made particularly rewarding progress in the important fields of anticancer (e.g. taxoids and camptothecins) and antimalarial (e.g. artemisinin compounds) therapies. In addition to purified plant-derived drugs, there is an enormous market for crude herbal medicines. Natural product research can often be guided by ethnopharmacological knowledge, and it can make substantial contributions to drug innovation by providing novel chemical structures and/or mechanisms of action. In the end, however, both plant-derived drugs and crude herbal medicines have to take the same pharmacoeconomic hurdle that has become important for new synthetic pharmaceuticals.

Effects of goyazensolide during in vitro cultivation of Schistosoma mansoni

Goyazensolide, a component extracted of Eremanthus goyazensis showed a significant inhibitory effect on egg-laying of Schistosoma mansoni during in vitro cultivation of this parasite. Motility of the worms was also reduced under treatment with goyazensolide and 90% of mortality was reached with concentrations up to 4 micrograms/ml. It has found that separated worms were more susceptible than worms pairing during drug exposition and female alone was significantly more susceptible than male worm in the same conditions of in vitro cultivation. Natural products isolated from plants represent potential sources for the identification of structures useful for the design of alternative molecules to be used as new drug substances against several infectious diseases.

Antiplasmodial activity of four Kenyan medicinal plants

A preliminary antiplasmodial and phytochemical screening of four Kenyan medicinal plants was carried out. The medicinal plants were extracted and tested for in vitro antiplasmodial activity against chloroquine-sensitive (K67) and chloroquine-resistant (ENT36) strains of Plasmodium falciparum. Out of 16 extracts, 12 were active against ENT36 strain while seven were active against K67 strain, that is, IC50 < or = 50 micrograms/ml. The most active extracts on both strains were those of leaves of Phyllanthus reticulatus Poir, and Suregada zanzibariensis Baill. (Euphorbiaceae) with IC50 < or = 10 micrograms/ml. The stembark of Terminalia spinosa Engl. (Combretaceae) and the stems of Dissotis brazzae Cogn. (Melastomataceae) had IC50 < or = 10 micrograms/ml for strains K67 and ENT36, respectively. A preliminary phytochemical analysis of these plants revealed the presence of different classes of primary and secondary metabolites.

Dreamtime, devastation and deviation: Australia's contribution to the chemotherapy of human parasitic infections

There are three areas in which Australian scientists have made outstanding contributions to the study of the chemotherapy of human parasitic infections. Naturally occurring products of plants have great potential as antiparasitic agents and although several native species have been shown to have antimalarial and anthelmintic activity, their potential as chemotherapeutic agents has not been fully realised; secondly, the demands of war ensured that the Army Malaria Unit at Cairns carried out meticulous and exceptional studies to evaluate new antimalarial compounds. Not only were they able to prove the effectiveness of atebrin, Proguanil and chloroquine as prophylactics, they also obtained much new information on the pharmacokinetics of antimalarials and about the infection itself. Full recognition of these pioneering studies involving over 1000 volunteers infected with malaria, which can never be repeated, has not been appreciated. The third significant contribution is the molecular studies on the mechanisms of drug resistance Plasmodium falciparum of both the antifolate- and quinoline-containing drugs and the identification and subsequent biochemical and molecular analysis of drug resistance in Giardia intestinalis infections.