Hepatoprotective properties in the rat of Mitracarpus scaber (Rubiaceae)

Kaempferol: Antimicrobial Properties, Sources, Clinical, and Traditional Applications

Flavonoids are a category of plant-derived compounds which exhibit a large number of health-related effects. One of the most well-known and studied flavonoids is kaempferol, which can be found in a wide variety of herbs and plant families. Apart from their anticarcinogenic and anti-inflammatory effects, kaempferol and its associated compounds also exhibit antibacterial, antifungal, and antiprotozoal activities. The development of drugs and treatment schemes based on these compounds is becoming increasingly important in the face of emerging resistance of numerous pathogens as well as complex molecular interactions between various drug therapies. In addition, many of the kaempferol-containing plants are used in traditional systems all over the world for centuries to treat numerous conditions. Due to its variety of sources and associated compounds, some molecular mechanisms of kaempferol antimicrobial activity are well known while others are still under analysis. This paper thoroughly documents the vegetal and food sources of kaempferol as well as the most recent and significant studies regarding its antimicrobial applications.

Ethnobotanical Research at the Kutukú Scientific Station, Morona-Santiago, Ecuador

This work features the results of an ethnobotanical study on the uses of medicinal plants by the inhabitants of the region near to the Kutukú Scientific Station of Universidad Politécnica Salesiana, located in the Morona-Santiago province, southeast of Ecuador. In the surroundings of the station, one ethnic group, the Shuar, has been identified. The survey hereafter reports a total of 131 plant species, with 73 different therapeutic uses.

In-vivo laxative and toxicological evaluation and in-vitro antitumour effects of Mitracarpus frigidus aerial parts

Objectives

To evaluate the in-vitro antitumour properties, and the in-vivo laxative and toxicological effects of the methanolic extract of the aerial parts of Mitracarpus frigidus (MFM).

Methods

The in-vitro antitumour activity of MFM was evaluated against three human tumour cell lines: Jurkat, HL60 and MCF-7. The laxative activity and the effect of MFM on intestinal motility were evaluated in rats at the doses of 100, 300 and 1000 mg/kg. Acute oral toxicity was performed at 10, 100, 1000 and 2000 mg/kg and subchronic toxicity was evaluated at 100, 300 and 1000 mg/kg of MFM during a 42-day period. After subchronic administration of MFM the biochemical, haematological and histopathological parameters were analysed. Also, the total content of anthraquinones was determined.

Key findings

MFM was cytotoxic only against HL60 and Jurkat cells with 89 and 83% growth inhibition, respectively. The laxative activity of MFM was similar to bisacodyl. Regarding the effect on intestinal motility, MFM showed a significant increase in the pathway of charcoal compared with the group treated with saline. Furthermore, MFM showed no in-vivo toxicity at the doses tested. Free and anthraquinone C- and O-glycosides were detected in MFM.

Conclusions

MFM showed significant antitumour activity for leukaemic cells. Moreover, it presented laxative potential and no in-vivo toxicity.

Mitracarpus frigidus aerial parts exhibited potent antimicrobial, antileishmanial, and antioxidant effects

The crude extract and the hexane, CH(2)Cl(2), EtOAc, n-BuOH, and hydromethanolic fractions of the aerial parts of Mitracarpus frigidus were evaluated against promastigote forms of two species of Leishmania (L. chagasi and L. amazonensis), 11 strains of bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica sorovar Tythimurium, Shigella sonnei, Klebsiella pneumoniae, Escherichia coli, Micrococcus luteus, Enterococcus faecalis, Enterobacter cloacae, Streptococcus pyogenes and Bacillus cereus) and two yeasts (Candida albicans and Cryptococcus neoformans). The antioxidant activity (DPPH radical scavenging activity and reducing power), cytotoxicity against mammalian cells, and the contents of phenolics and flavonoids were determined. Phytochemical analysis of the major groups of phytoconstituents is also reported. All samples showed antioxidant activity which was positively correlated to the content of phenolic compounds. S. sonnei, B. cereus and C. neoformans were susceptible to all extracts tested, except for the n-BuOH and hydromethanolic fractions, which demonstrated no antimicrobial activity. The lowest MIC was recorded for the CH(2)Cl(2) fraction against C. neoformans (MIC of 10 microg/ml), followed by B. cereus, S. sonnei, and E. cloacae (MIC of 20, 39 and 39 microg/ml, respectively). The CH(2)Cl(2) fraction was the most effective against L. chagasi (IC(50) of 6.7 microg/ml), and the hydromethanolic fraction exhibited the best activity against L. amazonensis (IC(50) of 9 microg/ml). A cytotoxic effect on mammalian cells was observed only for the crude extract and CH(2)Cl(2) fraction at the concentrations of 130 and 31 microg/ml, respectively. These results suggest that M. frigidus has interesting antimicrobial, antileishmanial and antioxidant activities.

Evaluation of Senegalese plants used in malaria treatment: focus on Chrozophora senegalensis

An ethnobotanical study was conducted in the Dakar area of Senegal to investigate the species used in the treatment of malaria. Seven plants are principally used: Cissampelos mucronata, Maytenus senegalensis, Terminalia macroptera, Bidens engleri, Ceratotheca sesamoides, Chrozophora senegalensis and Mitracarpus scaber. From a bibliographic study, it had been shown that the Cissampelos mucronata, Maytenus senegalensis and Terminalia macroptera have already been studied by several authors, and so only Bidens engleri, Ceratotheca sesamoides, Chrozophora senegalensis and Mitracarpus scaber were evaluated in the present study. For each plant, extracts were prepared with different solvents and tested in vitro on two chloroquine-resistant Plasmodium falciparum strains. Crude extracts from the leaves and the stems of Chrozophora senegalensis showed the best in vitro results. The IC(50) value of an aqueous extract of Chrozophora senegalensis was 1.6 microg/ml without cytotoxicity. The in vivo antiplasmodial activity of Chrozophora extracts was determined by both the oral and the intraperitoneal ways. The stages of Plasmodium cycle targeted by Chrozophora were then studied in vitro. These results could justify the traditional use of this plant in malaria treatment.

Hepatoprotective and antibacterial effects of extracts from Trichilia emetica Vahl. (Meliaceae)

Trichilia emetica Vahl. (Meliaceae) is a tree widely distributed in Tropical Africa. It has been used in Mali folk medicine for the treatment of various illnesses. The aim of this work was to study the hepatoprotective and antibacterial effects of a crude aqueous extract from Trichilia emetica root. An ethyl ether fraction from the aqueous extract was also prepared and studied. We have examined the hepatoprotective activity of the extracts on CCl4-induced damage in rat hepatocytes, their toxicity using the brine shrimp bioassay and their antibacterial activity against clinical isolated bacterial strains, which are commonly responsible for respiratory infections. A preliminary phytochemical analysis showed a high polyphenolic content in the aqueous extract and the presence of limonoids in the ethyl ether fraction. These latter compounds may be considered responsible for the good activity against the bacterial strains tested. Trichilia emetica extracts exerted also a significant (P<0.05) hepatoprotective effect at a dose of 1000 microg/ml both on plasma membrane and mitochondrial function as compared to silymarin used as a positive control. These activities may be a result of the presence of either polyphenols or limonoids. Finally, both the aqueous extract and its ethyl ether fraction did not show toxicity (LC50>1000 microg/ml) in the brine shrimp bioassay.

Cytotoxicity evaluation after coexposure to perchloroethylene and selected peroxidant drugs in rat hepatocytes

There is evidence of hepatotoxic effects caused by Perchloroethylene (PCE), presumably due to reactive metabolic intermediates; lipid peroxidation is under study as a potential mechanism of toxicity. We aimed to verify if PCE levels comparable to those reached in the blood of exposed subjects can cause cell damage and lipid peroxidation. The association of PCE with lipid peroxidation inducing drugs (cyclosporine A, valproic acid and amiodarone) was also tested on rat isolated hepatocytes. AST and LDH release, MTT test and lipid peroxidation assay showed that PCE determines dose-dependent effects on rat isolated hepatocytes. The toxic potential resulting from our data would be valproic acid < cyclosporine A < amiodarone. While valproic acid and cyclosporine caused a mild toxicity, the effects of amiodarone were more severe; in particular, the association of PCE with amiodarone showed a clear additive effect. The role of lipid peroxidation in the liver toxicity exerted by the tested compounds was confirmed by our data, and resulted relevant after treatment of cells with amiodarone and PCE. Extrapolating these results to human, we can suggest that a subject professionally exposed to PCE, who chronically assumes a lipid peroxidation inducing drug like amiodarone, may be potentially exposed to a higher risk of liver toxicity.

Azaanthraquinone inhibits respiration and in vitro growth of long slender bloodstream forms of Trypanosoma congolense

An ethanolic extract of Mitracarpus scaber was found to possess in vitro and in vivo trypanocidal activity against Trypanosoma congolense. At a dosage of 50 mg kg(-1) day(-1) in normal saline for 5 days, the extract cured Balbc mice infected with T. congolense without any relapse. The isolated active component benz(g)isoquinoline 5,10 dione (Azaanthraquinone) (AQ) purified from the extract was found to inhibit glucose-dependent cellular respiration and glycerol-3-phosphate-dependent mitochondrial O(2) assimilation of the long bloodstream forms of Trypanosoma congolense. On account of the pattern of inhibition, the target could be the mitochondrial electron transport system composed of glyceraldehyde 3-phosphate dehydrogenase (G3PDH). The azaanthraquinone specifically inhibited the reduced coenzyme Q(1)-dependent O(2) uptake of the mitochondria with respect to ubiquinone. The susceptible site could be due to ubiquinone redox system which links the two enzyme activities.

Antimicrobial activity of Mitracarpus scaber extract and isolated constituents

The antimicrobial activity of a methanol extract and isolated constituents of Mitracarpus scaber, a species used in folk medicine by West African native people, was evaluated against Staphylococcus aureus and Candida albicans strains. The mitracarpus methanol extract possesses both antibacterial and antimycotic activities (minimum inhibitory concentration-MIC 31.25 and 62.50 microg ml-, respectively). This extract was subsequently fractioned and monitored by bioassays leading to the isolation of seven compounds screened for antibacterial and antimycotic activities. Among these compounds, gallic acid and 3,4,5-trimethoxybenzoic acid inhibited the growth of Staph. aureus (MIC 3.90 and 0.97 microg ml-). 4-Methoxyacetophenone and 3,4,5-trimethoxyacetophenone effectively inhibited C. albicans (MIC 1.95 microg ml-). The other compounds (kaempferol-3-O-rutinoside, rutin and psoralen) which were also isolated showed low antibacterial and antimycotic activities (125-500 microg ml-).