Cajachalcone: An Antimalarial Compound from Cajanus cajan Leaf Extract.

Cajanus cajan L, a member of the family Fabaceae, was identified from the Nigerian antimalarial ethnobotany as possessing antimalarial properties. The bioassay-guided fractionation of the crude methanol extract of C. cajan leaves was done in vitro using the multiresistant strain of Plasmodium falciparum (K1) in the parasite lactate dehydrogenase assay. Isolation of compound was achieved by a combination of chromatographic techniques, while the structure of the compound was elucidated by spectroscopy. This led to the identification of a cajachalcone, 2',6'-dihydroxy-4-methoxy chalcone, as the biologically active constituent from the ethyl acetate fraction. Cajachalcone had an IC50 value of 2.0 µ g/mL (7.4 µ M) and could be a lead for anti-malarial drug discovery.

Ethnobotanical survey and cytotoxicity testing of plants of South-western Nigeria used to treat cancer, with isolation of cytotoxic constituents from Cajanus cajan Millsp. leaves.

ETHNOPHARMACOLOGICAL RELEVANCE: There is only scant literature on the anticancer components of medicinal plants from Nigeria, yet traditional healers in the area under study claim to have been managing the disease in their patients with some success using the species studied. AIM OF STUDY: To document plants commonly used to treat cancer in South-western Nigeria and to test the scientific basis of the claims using in vitro cytotoxicity tests. METHODS: Structured questionnaires were used to explore the ethnobotanical practices amongst the traditional healers. Methanol extracts of the most common species cited were screened for cytotoxicity using the sulforhodamine B (SRB) assay in both exposure and recovery experiments. Three cancer cell lines (human breast adenocarcinoma cell line MCF-7, human large cell lung carcinoma cell line COR-L23 and human amelanotic melanoma C32) and one normal cell line (normal human keratinocytes SVK-14) were used for the screening of the extracts and the fractions obtained. The extract of Cajanus cajan showed considerable activity and was further partitioned and the dichloromethane fraction was subjected to preparative chomatography to yield six compounds: hexadecanoic acid methyl ester, alpha-amyrin, beta-sitosterol, pinostrobin, longistylin A and longistylin C. Pinostrobin and longistylins A and C were tested for cytotoxicity on the cancer cell lines. In addition, an adriamycin-sensitive acute T-lymphoblastic leukaemia cell line (CCRF-CEM) and its multidrug-resistant sub-line (CEM/ADR5000) were used in an XTT assay to evaluate the activity of the pure compounds obtained. RESULTS: A total of 30 healers from S W Nigeria were involved in the study. 45 species were recorded with their local names with parts used in the traditional therapeutic preparations. Cytotoxicity (IC(50) values less than 50 microg/mL) was observed in 5 species (Acanthospermum hispidum, Cajanus cajan, Morinda lucida, Nymphaea lotus and Pycnanthus angolensis). Acanthospermum hispidum and Cajanus cajan were the most active. The dichloromethane fraction of Cajanus cajan had IC(50) value 5-10 microg/mL, with the two constituent stilbenes, longistylins A and C, being primarily responsible, with IC(50) values of 0.7-14.7 microM against the range of cancer cell lines. CONCLUSIONS: Most of the species tested had some cytotoxic effect on the cancer cell lines, which to some extent supports their traditional inclusion in herbal preparations for treatment of cancer. However, little selectivity for cancer cells was observed, which raises concerns over their safety and efficacy in traditional treatment. The longistylins A and C appear to be responsible for much of the activity of Cajanus cajan extract.

Antiplasmodial compounds from Cassia siamea stem bark extract.

Cassia siamea L. (Fabaceae) was identified from the southwest Nigerian ethnobotany as a remedy for febrile illness. This led to the bioassay-guided fractionation of stem bark of the plant extract, using the parasite lactate dehydrogenase assay and multi-resistant strain of Plasmodium falciparum (K1) for assessing the in vitro antimalarial activity. Emodin and lupeol were isolated from the ethyl acetate fraction by a combination of chromatographic techniques. The structures of the compounds were determined by spectroscopy, co-spotting with authentic samples and comparison with literature data. Both compounds were found to be the active principles responsible for the antiplasmodial property with IC(50) values of 5 microg/mL, respectively.

In vitro cytotoxicity studies of 20 plants used in Nigerian antimalarial ethnomedicine.

Twenty plants identified and selected from Southwest and Middle belt Nigerian antimalarial ethnopharmacology were evaluated for in vitro cytotoxicity using the brine shrimp lethality assay. The methanol extracts of 20 plant samples from 11 plant families were subjected to the assay. Of the studied plants, Lippia multiflora and Morinda lucida bark were found to be cytotoxic, with LC(50) values of 1.1 and 2.6 microg/ml, respectively. The least toxic plant extract was Bridelia micrantha (LC(50) value >9.0 x 10(6) microg/ml). Most of the plants were found to be relatively non-toxic.

The use of powder and essential oil of Cymbopogon citratus against mould deterioration and aflatoxin contamination of "egusi" melon seeds.

Experiments were carried out to determine the potential of using the powder and essential oil from dried ground leaves of Cymbopogon citratus (lemon grass) to control storage deterioration and aflatoxin contamination of melon seeds. Four mould species: Aspergillus flavus, A. niger, A. tamarii and Penicillium citrinum were inoculated in the form of conidia suspension (approx. 10(6) conidia per ml) unto shelled melon seeds. The powdered dry leaves and essential oil from lemon grass were mixed with the inoculated seeds at levels ranging from 1-10 g/100 g seeds and 0.1 to 1.0 ml/100 g seeds respectively. The ground leaves significantly reduced the extent of deterioration in melon seeds inoculated with different fungi compared to the untreated inoculated seeds. The essential oil at 0.1 and 0.25 ml/100 g seeds and ground leaves at 10 g/100 g seeds significantly reduced deterioration and aflatoxin production in shelled melon seeds inoculated with toxigenic A. flavus. At higher dosages (0.5 and 1.0 ml/100 g seeds), the essential oil completely prevented aflatoxin production. After 6 months in farmers' stores, unshelled melon seeds treated with 0.5 ml/ 100 g seeds of essential oil and 10 g/100 g seeds of powdered leaves of C. citratus had significantly lower proportion of visibly diseased seeds and Aspergillus spp. infestation levels and significantly higher seed germination compared to the untreated seeds. The oil content, free fatty acid and peroxide values in seeds protected with essential oil after 6 months did not significantly differ from the values in seeds before storage. The efficacy of the essential oil in preserving the quality of melon seeds in stores was statistically at par with that of fungicide (iprodione) treatment.

Efficacy of herbal remedies used by herbalists in Oyo State Nigeria for treatment of Plasmodium falciparum infections--a survey and an observation.

In the course of evaluating the contribution of phytomedicine to possible drug discovery of antimalarial drugs, an ethnomedical survey of specialized children traditional clinics was done. In the observational multi center study, efficacy of eight different herbal remedies, each consisting of 3-8 ingredients and administered by herbalists were investigated in clients enrolled in the six traditional clinics in Oyo (urban center) and Otu (rural center) of Oyo State, Nigeria. The clients, aged between six months and fifteen years with clinical symptoms of malaria were enrolled in the clinics of the herbalists, as their usual practice. Oral informed consents were obtained from their parents or guardians. Microscopic diagnosis of malaria infection was used to evaluate parasitaemia and validate efficacy of herbal remedies. Results of the analysis showed that, of the 163 clients of the herbalists, only 62 (30 from Oyo, 32 from Otu) had microscopically confirmed P. falciparum infection. Only results from 54 clients (29/30 (Oyo) and 25/32 (Otu) with P. falciparum infection could be evaluated. Plasmodium falciparum infection in 88% (23/29) of clients from Oyo responded to treatment with the herbal remedies while cure rate in clients from Otu was 42% (13/25). Parasite densities ranged from 171 to 53,613 parasites/microl blood and 87 to 36,209 parasites/microl blood in patients from Oyo and Otu respectively. The herbalists administered the remedies and Gossypium arboreum, Anarcadium occidentalis, Citrus medica, Phyllanthus amarus and Lippia multiflora were the main ingredients in the efficacious remedies. The herbalists gave detailed descriptions of each of the 8 herbal remedies proffered. The results confirm the efficacy of two of the eight herbal remedies, thereby validating the role of ethnomedicine as a possible source for the discovery of new chemotherapeutic agents in the treatment of P. falciparum malaria.

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%).

Antimicrobial potential of Spondias mombin, Croton zambesicus and Zygotritonia crocea.

The antimicrobial activity of Spondias mombin, Croton zambesicus and Zygotritonia crocea sourced from herbalists through an ethnobotanical survey of Egbado-South in Ogun State in Nigeria is reported. The extracts of the leaf of Spondias mombin and the stem bark of Croton zambesicus exhibited wide spectrum antibacterial effects comparable to those of ampicillin and gentamycin. The antifungal effect of extracts of Zygotritonia crocea and Croton zambesicus were comparable to those of tioconazole. There is justification for the use of these little studied medicinal plants as antiinfective agents in traditional medicine.

Antimicrobial screening of Bridelia, micrantha, Alchormea cordifolia and Boerhavia diffusa.

This report is on the antimicrobial potential of Bridelia micrantha, Alchornea cordifolia and Boerhavia diffusa sourced from traditional healers through an ethnobotanical survey of antiinfective plants in Egbado South in Ogun State, Nigeria. Extracts of B. micrantha and A. cordifolia exhibited significant inhibitory activity against the pathogenic organisms. In some cases, the antibacterial activity was comparable to those of ampicillin and gentamycin. However, only the leaf of A. cordifolia showed reasonable antifungal activity when compared with Trosyd. The study shows that there is justification for the use of these medicinal plants in traditional medicine.