Development, Characterization, and Evaluation of Novel Broad-Spectrum Antimicrobial Topical Formulations from Cymbopogon martini (Roxb.) W. Watson Essential Oil.

BACKGROUND: Skin infections were the most frequently encountered of all infections and the 4th leading cause of nonfatal disease burden. Topical drugs have been used for the management of skin infections. The growing concern of drug resistance to the topical agents has warned the need for continuous development of novel drug. Essential oils are the best candidate for new drug with different mode of action and target as they are rich in chemical constituents. OBJECTIVE: To evaluate and develop safe and effective topical antimicrobial formulations from essential oil of Cymbopogon martini. Method. Essential oil was extracted using hydrodistillation aerial part C. martini and topical formulations were prepared in five different semisolid bases. In vitro antimicrobial investigations were performed on essential oil and topical formulations. Skin sensitizations of the formulations were evaluated using guinea pig maximization. RESULTS: The essential oil of C. martini has shown broad-spectrum antimicrobial potency against all tested organisms with MIC value ranging from 0.65 to 10 µg/ml. Absolute inhibitions of growth of fungi were observed against Trichophyton mentagrophytes and Trichophyton rubrum at concentrations above 1% of oil and against Microsporum canis and Trichophyton verrucosum at a concentration of 4% oil. Among topical formulations, the highest antimicrobial activity was recorded in hydrophilic ointment followed by macrogol blend ointment. The antimicrobial activity of oil was higher in fungal pathogen compared to bacteria. Gram positive bacteria were more sensitive than gram negative bacteria. Hydrophilic and macrogol blend ointment containing 5% oil did not produce any skin sensitization on guinea pigs. CONCLUSION: In conclusion, topical formulations of C. martini essential oil can be alternative topical agents with safe broad-spectrum activity for the treatment of skin disorder. Further studies should focus on shelf life study and clinical study of the product.

Insecticidal Activity of Some Traditionally Used Ethiopian Medicinal Plants against Sheep Ked Melophagus ovinus.

Twelve medicinal plants and a commercially used drug Ivermectin were examined for insecticidal activity against Melophagus ovinus sheep ked at different time intervals using in vitro adult immersion test. The findings show that at 3.13 µL/mL, 6.25 µL/mL and 12.5 µL/mL concentration of Cymbopogon citratus, Foeniculum vulgare and Eucalyptus globulus essential oils respectively, recorded 100% mortalities against M. ovinus within 3 hour of exposure. Significantly higher insecticidal activity of essential oils was recorded (P = 0.00) when compared to 10 µ g/mL Ivermectin after 3-hour exposure of M. ovinus at a concentration of ≥1.57 µ L/mL, ≥3 µ L/mL, and ≥12.7 µ L/mL essential oils of C. citratus, F. vulgare, and E. globulus, respectively. Among essential oils, C. citratus has showed superior potency at a three-hour exposure of the parasite (P = 0.00) at a concentration of ≥0.78 µ L/mL. Strong antiparasitic activity was recorded by aqueous extract of Calpurnia aurea (80% mortality) at a concentration of 200 mg/mL within 24 h among aqueous extracts of 9 medicinal plants. The results indicated all the four medicinal plants, particularly those tested essential oils, can be considered as potential candidates for biocontrol of M. ovinus sheep ked.

Laboratory investigation of epidemic dropsy in Addis Ababa, Ethiopia.

BACKGROUND: Food adulteration including adulteration of edible oils may cause serious health problems. One of the most common edible adulterants is argemone oil. An outbreak of epidemic dropsy occurred in Addis Ababa during May-June, 2008. One hundred and eighty two cases were recorded with twelve confirmed deaths. Dietary history of the cases revealed that vegetable oils were the usual cooking medium. OBJECTIVE: The aim of the study was hence to investigate the causes of this outbreak. METHODS: Contaminant identification was done using standard chemical tests, complemented with TLC. Toxicity study was done using Swiss albino mice feed with contaminated and non contaminated standard diet for 30 days. RESULTS: Laboratory investigation of the edible oils has indicated that 47 of the 280 edible oils analyzed were adulterated with argemone oil. About 81% of the edible oil samples collected from Lideta sub-city were adulterated with argemone oil. Toxicological investigation of the adulterated oils also indicated typical features of argemone alkaloid poisoning in mice. CONCLUSION: Results of both laboratory analysis and toxicological studies confirmed consumption of edible oils adulterated with argemone oil as the cause of epidemic dropsy in Addis Ababa.

In-vivo antipyretic studies of the aqueous and ethanol extracts of the leaves of Ajuga remota and Lippia adoensis.

BACKGROUND: There are quite large number of traditionally used plants that are used to treat ailments associated with fever in the ethnomedical system of Ethiopia. Most of them, however, have not been subjected to scientific investigation for their efficacy and safety. OBJECTIVES: To evaluate the antipyretic effects of the aqueous and ethanol extracts of the leaves of Ajuga remota and Lippia adoenesis. DESIGN: An experimental design in which five group of in-house bred albino mice weighing 30-35 g representing positive and negative control, and three dose levels extract treated groups, respectively was employed. The extracts, standard drugs and distilled water were administered into GIT by gavage to evaluate the antipyretic effect after inducing pyrexia in mice. RESULTS: All extracts of both plants that were administered orally at doses of 50, 100 and 200 mg per kg showed antipyretic property. The antipyretic effects were observed to be dose dependent. In both plants, the aqueous extract was found to have more potent antipyretic effect than the ethanol extract. No mouse manifested toxic effects at any dose levels of all the extracts for the observed period of two weeks. CONCLUSION: The present study show that both extracts of the investigated plants have got antipyretic effects and the extracts are effective and safe at the doses tested. This supports the traditional claim or use of these plants.

Screening of some medicinal plants of Ethiopia for their anti-microbial properties and chemical profiles.

In the indigenous health care delivery system of Ethiopia, numerous plant species are used to treat diseases of infectious origin. Regardless of the number of species, if any of such claims could be verified scientifically, the potential significance for the improvement of the health care services would be substantial. The objective of this study was, therefore, to determine the presence of anti-microbial activity in the crude extracts of some of the commonly used medicinal plants as well as to identify the class of compounds in the plants that were subjected to such screening. Thus, the crude methanol, petroleum ether and aqueous extracts of 67 plant species were subjected to preliminary screening against 10 strains of bacterial species and 6 fungal strains using the agar dilution method. A sample concentration of 250-2000 microg/ml and 500-4000 microg/ml were used for the bacterial and fungal pathogens, respectively. The results indicated that 44 different plant species exhibited activity against one or more of the bacteria while one species, viz., Albizzia gummifera showed activity against all the 10 bacteria at different gradient of dilution. Twenty three species inhibited or retarded growth of one or more organisms at dilution as low as 250 microg/ml. Extracts of same plants species were also tested against six different fungal pathogenic agents of which eight species showed growth inhibition against one or more of the organisms. Trichila emetica and Dovyalis abyssinica, which inhibited growth of four and five fungal strains at 100 microg/ml concentration, respectively, were the most promising plants. Chemical screening conducted on the extracts of all the plants showed the presence of several secondary metabolites, mainly, polyphenols, alkaloids, tannins sterols/terpenes, saponins and glycosides. The plants containing more of these metabolites demonstrated stronger anti-microbial properties stressing the need for further investigations using fractionated extracts and purified chemical components.

Analgesic properties of some ethiopian medicinal plants in different models of nociception in mice.

Many people use analgesic plants to relieve pain and inflammation though most of them have not yet been proved to possess such properties. The objective of the present study was to screen the aqueous and ethanol extracts of four Ethiopian traditionally used medicinal plants for analgesic properties. Aqueous and ethanol extracts of the plant materials were screened for their analgesic properties in mice using tail-flick, hot-plate and tail-pinch tests at three dose levels. Normal saline and standard analgesics were employed as negative and positive controls, respectively. The plants subject for the present screening were Ocimum suave, Ocimum lamiifolium, Lippia adoensis, and Ajuga remota. All extracts were observed to possess analgesic properties with varying potencies in tail-flick and hot-plate tests. Analgesic activity, however was not observed with tail-pinch test. The analgesic potencies also varied with concentrations and time after administration. From the present findings, it can be concluded that the extracts of all the plant materials have got analgesic properties with fast onset of action whose mechanisms need to be investigated further.

Antipyretic properties of the aqueous and ethanol extracts of the leaves of Ocimum suave and Ocimum lamiifolium in mice.

Numerous plant species are used to treat ailments associated with pyrexia in the indigenous health care delivery system of Ethiopia. Notable among these are Ocimum suave and Ocimum lamiifolium. The objective of the present study was thus to evaluate the antipyretic effects of the aqueous and ethanol extracts of the leaves of Ocimum suave and Ocimum lamiifolium in mice. Rectal temperatures were recorded before and after inducing pyrexia as well as after administration of the respective extracts every half an hour for 3h. Parallel experiments were run with a standard antipyretic (acetylsalicylic acid) and the vehicle (distilled water). All the plant extracts showed antipyretic property with reasonable onset and duration of action. Both ethanol and aqueous extracts of Ocimum suave were observed to be more potent than those of Ocimum lamiifolium. Aqueous extract of Ocimum suave and ethanol extract of Ocimum lamiifolium were more potent than their other counterpart extracts. Time dependent antipyretic effect was also observed with some extracts; reduced with time with aqueous extract of Ocimum suave and increased with time with both extracts of Ocimum lamiifolium.