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1.  Antimalarial evaluation of the leaf latex of Aloe citrina and its major constituent 
Ancient Science of Life  2015;34(3):142-146.
Malaria is one of the major obstacles to the socioeconomic development of several developing countries. Adequate treatment of the disease is becoming increasingly difficult due to the worsening problems of drug resistance in many parts of the world. Therefore, increased efforts in antimalarial drug discovery are urgently needed.
This study was designed to evaluate the antimalarial activity of the leaf latex of Aloe citrina Carter and Brandham and its major constituent.
Materials and Methods:
The leaf latex of A. citrina was dissolved in methanol and subjected to preparative thin layer chromatography. Structure of the isolated compound was determined on the basis of its electrospray-ionization tandem mass spectrometry, 1H, 13C NMR and DEPT spectral data. The latex and its isolated compound were tested for their in vivo antimalarial activity using a 4-day suppressive test against chloroquine sensitive ANKA strain of Plasmodium berghei in mice.
Homonataloin A/B was isolated as a major component of the latex. Both the latex and isolated compound exhibited significant (P < 0.001) antimalarial activity at a dose of 400 mg/kg with parasite suppression of 60.59% and 67.52%, respectively. No significant adverse signs of toxicity were observed in mice treated with the leaf latex up to the highest dose (5000 mg/kg).
The results of this study indicate that the antimalarial activity of the plant is attributed in part or in full to the presence of homonataloin A/B in the latex. It also validates the traditional use of the plant as an antimalarial agent.
PMCID: PMC4458904  PMID: 26120228
4-day suppressive test; acute toxicity; Aloe citrina; antimalarial activity; homonataloin A/B
2.  Evaluation of anxiolytic activity of the essential oil of the aerial part of Foeniculum vulgare Miller in mice 
Foeniculum vulgare locally known as ensilal, is an aromatic plant widely cultivated in temperate and tropical regions. The anti-anxiety activity of the crude extract of F. vulgare has been reported. However, the fraction responsible for anxiolytic activity is not known and there is no any report on the anti-anxiety activity of the essential oil of F. vulgare. The objective of study was to evaluate the anxiolytic activity of the essential oil of Foeniculum vulgare Miller.
Adult Swiss albino male mice were randomly divided into six groups (n = 6). Groups I and II received Tween 80 (5%, v/v) and diazepam (0.5 mg/kg, ip), respectively, while groups III to V received orally 50, 100, and 200 and 400 mg/kg doses of the essential oil of F. vulgare, respectively. The mice were then individually placed in animal anxiety models: elevated plus maze (EPM), staircase test (SCT) and open field test (OFT) and evaluated for various parameters.
In EPM test, 100 and 200 mg/kg doses of the essential oil significantly increased percent number of entries and time spent in open arms compared to control. In SCT these doses also reduced rearing significantly compared to controls, while only the 200 mg/kg dose significantly increased number of squares crossed at the center in the OFT test.
The essential oil of F. vulgare was found to exhibit a promising anxiolytic activity.
PMCID: PMC4156641  PMID: 25149087
Anxiolytic activity; Foeniculum vulgare; Essential oil; Mice
3.  Antitrypanosomal activity of aloin and its derivatives against Trypanosoma congolense field isolate 
There is an urgent need for the development of new, cheap, safe and highly effective drugs against African trypanosomiasis that affects both man and livestock in sub-Saharan Africa including Ethiopia. In the present study the exudate of Aloe gilbertii, an endemic Aloe species of Ethiopia, aloin, aloe-emodin and rhein were tested for their in vitro and in vivo antitrypanosomal activities against Trypanosoma congolense field isolate. Aloin was prepared from the leaf exudate of A. gilbertii by acid catalyzed hydrolysis. Aloe-emodin was obtained by oxidative hydrolysis of aloin, while rhein was subsequently derived from aloe-emodin by oxidation. In vitro trypanocidal activity tests were conducted on parasites obtained from infected mice, while mice infected with T. congolense were used to evaluate in vivo antitrypanosomal activity of the test substances.
Results of the study showed that all the test substances arrested parasites motility at effective concentration of 4.0 mg/ml within an incubation period ranging from 15 to 40 min. Moreover, the same concentration of the test substances caused loss of infectivity of the parasites to mice during 30 days observation period. Among the tested substances, rhein showed superior activity with minimum inhibitory concentration (MIC) of 0.4 mg/ml. No adverse reactions were observed when the test substances were administered at a dose of 2000 mg/kg. Rhein at doses of 200 and 400 mg/kg, and the exudate, aloin and aloe-emodin at a dose of 400 mg/kg reduced the level of parasitaemia significantly (P < 0.05) and improved anaemia.
The results obtained in this investigation indicate that aloin and its derivatives particularly rhein have the potential to be used as a scaffold for the development of safe and cost effective antitrypanosomal drugs that can be useful in the continuing fight against African trypanosomiasis.
PMCID: PMC3984735  PMID: 24612613
African trypanosomiasis; Aloe gilbertii; Aloin; Aloe-emodin; Rhein; Antitrypanosomal activities; Trypanosoma congolense
4.  Evaluation of the effects of 80% methanolic leaf extract of Caylusea abyssinica (fresen.) fisch. & Mey. on glucose handling in normal, glucose loaded and diabetic rodents 
The leaves of Caylusea abyssinica (fresen.) Fisch. & Mey. (Resedaceae), a plant widely distributed in East African countries, have been used for management of diabetes mellitus in Ethiopian folklore medicine. However, its use has not been scientifically validated. The present study was undertaken to investigate antidiabetic effects of the hydroalcoholic leaf extract of C. abyssinica extract in rodents.
Materials and method
Male Animals were randomly divided into five groups for each diabetic, normoglycemic and oral glucose tolerance test (OGTT) studies. Group 1 served as controls and administered 2% Tween-80 in distilled water, (TW80); Group 2 received 5 mg/kg glibenclamide (GL5); Groups 3, 4 and 5 were given 100 (CA100), 200 (CA200) and 300 (CA300) mg/kg, respectively, of the hydroalcoholic extract of C. abyssinica. Blood samples were then collected at different time points to determine blood glucose levels (BGL). Data were analyzed using one way ANOVA followed by Dunnet’s post hoc test and p < 0.05was considered as statistically significant.
In normal mice, CA200 and GL5 induced hypoglycemia starting from the 2nd h but the hypoglycemic effect of CA300 was delayed and appeared at the 4th h (p < 0.05 in all cases). In diabetic mice, BGL was significantly reduced by CA100 (p < 0.05) and CA300 (p < 0.01) starting from the 3rd h, whereas CA200 (p < 0.001) and GL5 (p < 0.05) attained this effect as early as the 2nd h. In OGTT, TW80 (p < 0.01) and CA100 (p < 0.01) brought down BGL significantly at 120 min, while CA200 (p < 0.001) and GL5 (p < 0.001) achieved this effect at 60 min indicating the oral glucose load improving activity of the extract. By contrast, CA300 was observed to have no effect on OGTT. Acute toxicity study revealed the safety of the extract even at a dose of 2000 mg/kg. Preliminary phytochemical study demonstrated the presence of various secondary metabolites, including, among others, saponins, flavonoids and alkaloids.
The results indicate that C. abyssinica is endowed with antidiabetic and oral glucose tolerance improving actions, particularly at the dose of 200 mg/kg in experimental animals. These activities of the plant extract may be related to the presence of secondary metabolites implicated in antidiabetic activities of plant extracts via different hepatic and extra-hepatic mechanisms. These results thus support the traditional use of the leaf extract for the management of diabetes mellitus.
PMCID: PMC3495218  PMID: 22967092
Caylusea abyssinica; Diabetes; Hypoglycemic effect
5.  Ethnomedical survey of Berta ethnic group Assosa Zone, Benishangul-Gumuz regional state, mid-west Ethiopia 
Traditional medicine (TM) has been a major source of health care in Ethiopia as in most developing countries around the world. This survey examined the extent and factors determining the use of TM and medicinal plants by Berta community. One thousand and two hundred households (HHs) and fourteen traditional healers were interviewed using semi-structured questionnaires and six focused group discussions (FGDs) were conducted. The prevalence of the use of TM in the two weeks recall period was 4.6%. The HH economic status was found to have a significant effect while the educational level and age of the patients have no effect either on the care seeking behavior or choice of care. Taking no action about a given health problem and using TM are common in females with low-income HHs. Forty plant species belonging to 23 families were reported, each with local names, methods of preparation and parts used. This study indicates that although the proportion of the population that uses TM may be small it is still an important component of the public health care in the study community as complementary and alternative medicine.
PMCID: PMC2688485  PMID: 19409096

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