Enhancing the antimalarial activity of artesunate

The global challenge to the treatment of malaria is mainly the occurrence of resistance of malaria parasites to conventionally used antimalarials. Artesunate, a semisynthetic artemisinin compound, and other artemisinin derivatives are currently used in combination with selected active antimalarial drugs in order to prevent or delay the emergence of resistance to artemisinin derivatives. Several methods, such as preparation of hybrid compounds, combination therapy, chemical modification and the use of synthetic materials to enhance solubility and delivery of artesunate, have been employed over the years to improve the antimalarial activity of artesunate. Each of these methods has advantages it bestows on the efficacy of artesunate. This review discussed the various methods employed in enhancing the antimalarial activity of artesunate and delaying the emergence of resistance of parasite to it.

Mesoporous silica nanocarriers encapsulated antimalarials with high therapeutic performance

The use of nanocarriers in drug delivery is a breakeven research and has received a clarion call in biomedicine globally. Herein, two newly nano-biomaterials: MCM-41 encapsulated quinine (MCM-41 ⊃ QN) (1) and 3-phenylpropyl silane functionalized MCM-41 loaded QN (pMCM-41 ⊃ QN) (2) were synthesized and well characterized. 1 and 2 along with our two already reported nano-antimalarial drugs (MCM-41 ⊃ ATS) (3) and 3-aminopropyl silane functionalized MCM-41 contained ATS (aMCM-41 ⊃ ATS) (4) were screened in vitro for their activity against P. falciparium W2 strain, cytotoxicity against BGM cells and in vivo for their activity against Plasmodium bergheiNK65. 1 has the highest antimalarial activity in vivo against P. berghei NK65, (ED50: < 0.0625 mg/kg body weight) and higher mean survival time compared to the other nano biomaterials or unencapsulated drugs at doses higher than 0.0625 mg/kg body weight. This encapsulation strategy of MCM-41 ⊃ QN (1) stands very useful and effective in delivering the drug to the target cells compared to other delivery systems and therefore, this encapsulated drug may be considered for rational drug design.

In vivo antimalarial activity and toxicological effects of methanolic extract of Cocos nucifera (Dwarf red variety) husk fibre

OBJECTIVE

Phytochemical constituents as well as antimalarial and toxicity potentials of the methanolic extract of the husk fibre of Dwarf Red variety of Cocos nucifera were evaluated in this study.

METHODS

The dried powdered husk fibre was exhaustively extracted with hexane, ethyl acetate and methanol successively and the methanolic extract was screened for flavonoids, phenolics, tannins, alkaloids, steroids, triterpenes, phlobatannins, anthraquinones and glycosides. A 4-day suppressive antimalarial test was carried out using Plasmodium berghei NK65-infected mice, to which the extract was administered at doses of 31.25, 62.5, 125, 250 and 500 mg/kg body weight (BW). Toxicity of the extract was evaluated in rats using selected hematological parameters and organ function indices after orally administering doses of 25, 50 and 100 mg/kg BW for 14 d.

RESULTS

Phytochemical analysis revealed the presence of alkaloids, tannins, phenolics, saponins, glycosides, steroids and anthraquinones in the extract. Moreover, the extract reduced parasitemia by 39.2% and 45.8% at doses of 250 and 500 mg/kg BW respectively on day 8 post-inoculation. Various hematological parameters evaluated were not significantly altered (P>0.05) at all doses of the extract, except red blood cell count which was significantly elevated (P<0.05) at 100 mg/kg BW. The extract significantly increased (P<0.05) urea, creatinine, cholesterol, high-density lipoprotein-cholesterol and bilirubin concentrations in the serum as well as atherogenic index, while it reduced albumin concentration significantly (P<0.05) at higher doses compared to the controls. Alanine aminotransferase activity was reduced in the liver and heart significantly (P<0.05) but was increased in the serum significantly (P<0.05) at higher doses of the extract compared to the controls.

CONCLUSION

The results suggest that methanolic extract of the Dwarf red variety has partial antimalarial activity at higher doses, but is capable of impairing normal kidney and liver function as well as predisposing subjects to cardiovascular diseases.

Ethnobotanical survey of medicinal plants used in the treatment of malaria in Ogbomoso, Southwest Nigeria

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria infection is the second largest killer disease after HIV in Nigeria. Failure of the orthodox medications due to drug adulteration, high cost of procurement of antimalarial drugs and inconvenience experienced in the use of high dosage of the new antimalarial drug combination therapy has turned the attention of the people in the world towards the use of local herbs.

MATERIALS AND METHODS

An ethnobotanical survey of medicinal plants used by the indigenous people of Ogbomoso for the treatment of malaria infection was conducted. Investigations were carried out on the names of plants, their parts (leaf, stem or root) used, method of preparing herbal antimalarial remedies, likely side effect and how it is administered were recorded through the use of a structured questionnaire.

RESULTS

The results of the survey revealed that 40 plant species from 32 plant families were mostly used for treating malaria infection in Ogbomoso. Twenty-three different antimalarial recipes were mentioned in the survey. The Asteraceae and Anacardinceae were the most represented plant families followed by Malvaceae, Solanaceae, Annonaceae, Poaceae, Rutaceae and Meliaceae. The leaf and the stem bark have been the most frequently used plant parts while concoction and decoction were the most common method of preparation. Treatment regimens of malaria generally included drinking, bathing and steam inhalation of the aqueous herbal preparations for 5-7 days or until symptoms of malaria disappear. About 53% of the plants mentioned in the survey had side effect.

CONCLUSIONS

Hence, the need for documentation of these plants for further investigation becomes necessary.

Characterizing thermoluminescence properties of calcium halophosphate fluorescent coating powder for radiation dosimetry

The thermoluminescence (TL) and other properties of calcium halophosphate fluorescent coating powder were studied in detail with the sole aim of ascertaining its suitability for use as a dosimetric material. The shape of the glow curve (peaks at about 125 degrees C and 350 degrees C) as well as its fairly linear dose response even at very high doses are indicative of its suitability. Optical properties of the material were studied using Infrared spectroscopy (IR) and UV-Visible spectrophotometry. The IR spectrum shows a prominent peak at 3425.9 cm(-1) indicating the presence of OH and N-H bonds. The material absorbs sharply at wavelength between 196 nm and 220 nm. The material exhibits high transmittance at various peaks with corresponding wavelengths from 300 to 831 nm. This material can also find application in radiation therapy associated with very high accident dosimetry as well as in material testing.