Thymus species in Ethiopia: Distribution, medicinal value, economic benefit, current status and threatening factors

The genus Thymus is one of the genera in the family Lamiaceae. In Ethiopia, it is represented by two endemic species namely Thymus serrulatus and Thymus schimperi. The aims of this study were to identify the types of species from six geographically distant localities in Ethiopia, assess the ethnobotanical and socioeconomic information of these species in these localities and gather information about the current status and threatening factors of these species in the six localities. The plant specimens from these localities were authenticated by experts in the National Herbarium of Addis Ababa University as Thymus serrulatus and Thymus schimperi. The plants were rated by local informants as treatments for ailments like blood pressure (30.7%), general pain syndrome (10%), influenza (10%), abdominal pain (10%), ascariasis (2.9%), and intestinal parasites (2.9%). The informants rated the economic value of these plants as animal forage (71.5%), bee forage (71.5%), condiments (68%), and washing and fumigation (46%). According to the informants, the status of Thymus species is declining from time to time due to overgrazing (80.7%), agricultural expansion (64.2%), overharvesting (48.57%), uprooting during harvesting (14.2%), and lack of recognition (13.6%)Keywords: Ethiopia, Thymus schimperi, Thymus serrulatus, threatening factor

Toxicity study in mice of resins of three Commiphora species

Acute toxicity studies of crude extracts of resins of Commiphora myrrha, C. guidottii and C. erlangeriana, and pure compounds isolated from C. erlangeriana were conducted on Swiss albino mice. The extract from C. erlangeriana had a mean LD50 of 410 mg/kg body weight. However the extracts from C. myrrha and C. guidotti were not toxic at the doses tested. The pure compound isolated from C. erlangeriana, erlangerin D (1) demonstrated a mean LD50 of 140 mg/kg body weight. On the other hand erlangerin A (2) was not toxic to the mice at even four times the LD50 value of erlangerin D (1). Key words/phrases: Commiphora erlangeriana, C. guidotti, C. myrrha, myrrh, opopanax SINET: Ethiopian Journal of Science Vol.26(2) 2003: 151-15

Toxicity study and antibacterial effects of the leaves extracts of Boscia coriacea and Uvaria leptocladon

BACKGROUND: The objective of this study was to evaluate the in vivo toxicity and antibacterial activity of the leaves extracts of Boscia coriacea and Uvaria leptocladon.METHODS: Extraction was performed using 80% methanol by maceration and Soxhlet extraction method. Evaluation of the acute toxicity of the extracts was based on the Organization for Economic Cooperation and Development (OECD) guideline. Evaluation of antibacterial activity of the extracts was done by agar well diffusion assay. Determinations of minimum inhibitory concentrations (MIC) of the extracts were performed by broth macro-dilution method. The checkerboard method was used for the determination of combined effect of antibiotics and the extracts.Paired T-test and one way analysis of variance were used for statistical analysis.RESULTS: B. coriacea and U. leptocladon have no toxic effect in Swiss albino mice up to dose of 5000 mg/kg. B. coriacea and U. leptocladon showed antibacterial activity at concentration of 500 mg/ml. The chloroform-methanol fraction of B. coriacea and U. leptocladon showed the highest antibacterial activity at concentration of 25 mg/ml. The MIC and minimum bactericidal concentration (MBC) of B. coriacea were 125 mg/ml and 250mg/ml, respectively. The MIC of U. leptocladon ranged from 31.25 mg/ml to 62.5 mg/ml, while its MBC ranged from 62.5 to 125 mg/ml. The combination assay of B. coriacea and the antibiotics showed additive effect, while U. leptocladon and the antibiotics showed indifferent effect.CONCLUSION: The findings showed that U. leptocladon and B. coriacea leaves extracts have antibacterial activity and no toxicity in animal model

Anti-inflammatory and phytochemical analysis of the crude leaves extracts of Boscia Coriacea Graells and Uvaria Leptocladon Oliv

BACKGROUND: The objective of this study was to evaluate the anti-inflammatory activities and phytochemical composition of the leaves extracts of Boscia coriacea Graells and Uvaria leptocladon Oliv.METHODS: The powdered leaves of Boscia coriacea Graells and Uvaria leptocladon Oliv were extracted by maceration and soxhlet extraction methods. Anti-inflammatory activity of the leaves extracts of Boscia coriacea Graells and Uvaria leptocladon Oliv were evaluated using carrageenan-induced paw edema model. Standard methods were used for analysis of phytochemical composition of the leaves extracts of Boscia coriacea Graells and Uvaria leptocladon Oliv. Data analysis was done using one way analysis of variance.RESULTS: U. leptocladon Oliv (200 mg/kg) and B. coriacea Graells (200 mg/kg) showed percent inhibition on mice paw edema of 86% and 75% after six hours of carrageenan injection, respectively. The ethanol fraction (100 mg/kg) of U. leptocladon Oliv showed the highest anti- inflammatory effect after six hours of carrageenan injection. The phytochemical analysis of the leaves extracts of B. coriacea and U. leptocladon revealed the presence of tannins, alkaloids, cardiac glycoside, flavonoids, phenols, quinones, and saponins.CONCLUSION: The crude leaves extracts of B. coriacea Graells and U. leptocladon Oliv contain phytochemicals with antiinflammatory activities

Further studies on the phlebotomine sandflies of the kala-azar endemic lowlands of Humera-Metema (north-west Ethiopia) with observations on their natural blood meal sources

<p>Abstract</p> <p>Background</p> <p>Visceral leishmaniasis (VL) has been known to exist in northwest Ethiopia (Humera-Metema lowlands) since the early 1970s associated with large scale agricultural development activities, often resulting in outbreaks. The latest outbreak of the disease that has started around 1995 in both regions, has led to the present preliminary entomological surveys (1996-2005) the results of which are reported here. Sandflies were collected using CDC light traps and <it>Phlebotomus </it>females were dissected for <it>Leishmania </it>detection and isolation; freshly fed <it>Phlebotomus </it>females collected were subsequently tested for their blood meal sources using ELISA. All <it>Phlebotomus </it>collections were identified to species.</p> <p>Results</p> <p>During the surveys (1996-2005), a total of 1963 sandflies of six <it>Phlebotomus </it>species (<it>P. orientalis</it>, <it>P. papatasi</it>, <it>P. bergeroti, P. duboscqi</it>, <it>P. rodhaini </it>and <it>P. alexandri</it>) were recorded from the study areas: the predominant species was <it>P. orientalis </it>in both localities. None of the total 618 <it>P. orientalis </it>females dissected (506 from Metema and 112 from Humera), nor the total 114 females of four other species dissected (<it>P. papatasi</it>, <it>P. duboscqi</it>, <it>P. bergeroti </it>and <it>P. rodhaini</it>) was infected with <it>Leishmania </it>promastigotes. ELISA-based blood meal analysis of 273 fresh fed <it>P. orientalis </it>females collected from Metema revealed a remarkably high bovine blood feeds (92%) with only 2.2% of human blood feeds.</p> <p>Conclusion</p> <p>Based on abundance and other circumstantial evidences (its proven role in Sudan), <it>P. orientalis </it>is the most likely vector of VL in northwest Ethiopia, pending further clarifications. The zoophagic feeding behaviour of <it>P. orientalis </it>detected in the present study could have epidemiological significance, but more investigations are required in this and other behavioural characteristics towards appropriate management of the vector.</p

Evaluation of the GenoType MTBDRplus assay for detection of rifampicin- and isoniazid-resistant Mycobacterium tuberculosis isolates in central Ethiopia

AbstractObjective/Background: Multidrug-resistant tuberculosis (MDR-TB) is growing globally and becoming a major challenge for national TB control programs. Therefore, rapid identification of MDR strains of Mycobacterium tuberculosis and monitoring their transmission could contribute significantly to the control of TB. The GenoType MTBDRplus assay has been recommended by the World Health Organization to identify rifampicin (RIF)- and isoniazid (INH)-resistant M. tuberculosis isolates. This study was carried out to evaluate the performance of the GenoType MTBDRplus assay for the detection of RIF- and INH-resistant M. tuberculosis isolates in central Ethiopia. Methods: A total of 279 M. tuberculosis strains isolated from active TB cases in central Ethiopia were evaluated for their drug sensitivity by the conventional drug-susceptibility test (DST) and compared with data derived from the GenoType MTBDRplus assay. The DST served as the gold standard for evaluating the GenoType MTBDRplus assay. Results: The sensitivity and specificity of the GenoType MTBDRplus assay for the detection of RIF-resistant M. tuberculosis isolates were 80.0% and 99.6%, respectively. Its sensitivity and specificity for the detection of INH-resistant M. tuberculosis isolates were 82.7% and 99.6%, respectively, whereas they were 75.0% and 100%, respectively, for the detection of MDR M. tuberculosis strains. The concordances of the GenoType MTBDRplus assay and the conventional DST for the detection of RIF and INH susceptibility were 80% (8/10) and 86.2% (25/29), respectively. Furthermore, the concordance of the two tests for the detection of MDR M. tuberculosis strains was 75%. Specific mutations were detected in 55.6% (5/9) of the RIF-resistant isolates, with the highest mutation rate (33.3%) for the rpoB gene (Codon S531L). For INH-resistant isolates, the highest mutation rate (88.8%) related to a katG mutation (Codon S315T1). Conclusion: The findings of this study revealed that the GenoType MTBDRplus assay has high sensitivity and specificity for the detection of RIF and INH resistance. These preliminary data support the notion that the assay should be considered as an alternative to the DST for the characterization of MDR in M. tuberculosis isolates and the control of TB

Sodium Stibogluconate (SSG) & Paromomycin Combination Compared to SSG for Visceral Leishmaniasis in East Africa: A Randomised Controlled Trial

Visceral leishmaniasis (VL) is a parasitic disease with about 500,000 new cases each year and is fatal if untreated. The current standard therapy involves long courses, has toxicity and there is evidence of increasing resistance. New and better treatment options are urgently needed. Recently, the antibiotic paromomycin (PM) was tested and registered in India to treat this disease, but the same dose of PM monotherapy evaluated and registered in India was not efficacious in Sudan. This article reports the results of a clinical trial to test the effectiveness of injectable PM either alone (in a higher dose) or in combination with sodium stibogluconate (SSG) against the standard SSG monotherapy treatment in four East African countries—Sudan, Kenya, Ethiopia and Uganda. The study showed that the combination of SSG &PM was as efficacious and safe as the standard SSG treatment, with the advantages of being cheaper and requiring only 17 days rather than 30 days of treatment. In March 2010, a WHO Expert Committee recommended the use of the SSG & PM combination as a first line treatment for VL in East Africa

Types of anaemia due to hookworm infection among the populations of Wolisso

Abstract: A community-based cross-sectional study to investigate the association between hookworm infection and anaemia was carried out on 227 apparently healthy individuals living around Wolisso. Of these subjects, 155 were positive and 72 were negative for hookworm infections. It was found out that 32 (20.6%) of the hookworm positvie and 4 (5.6%) of the hookworm negative individuals were anaemic. Chi-square analysis showed hookworm infection was significantly associated with low haemoglobin (Hb), low transferrin saturation (TS) and low ferritin levels. Intensity of infection as expressed in eggs per gram of faeces showed a highly significant negative association with TS and serum ferritin levels (p&lt;0.001) but not with Hb levels. The degree of anaemia could be considered as mild, however, the light hookworm infection could possibly lead to iron deficiency anaemia. When multiple criteria involving elevated mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), and macrocytic blood picture were taken as suggestive of a macrocytic type of anaemia, 20 (13.0%) of the hookworm positive and 4 (5.6%) of the hookworm negative individuals fell into this category. However, the association between parameters suggestive of macrocytic anaemia and hookworm infection was not strong. [Ethiop. J. Health Dev. 1999;13(1):33-39

Toxicity and Oviposition Deterrent Activities of Thyme Essential Oils against Anopheles arabiensis

Background. Malaria is one of the deadliest mosquito-borne diseases in sub-Saharan Africa and Ethiopia. Owing to their costs and environmental issues, synthetic insecticides are poor choices to control mosquitoes. Plant-based products can be considered as safe and biodegradable alternatives. The present study aimed to test the toxicity and oviposition deterrent activities of Thymus serrulatus and Thymus schimperi essential oils (EOs) against Anopheles arabiensis. Methods. Thyme EOs were extracted by hydrodistillation using the Clevenger-type apparatus. They were named Tar, Ala, and Yil after the areas of thyme collection Tarmaber, Alamata, and Yilmana Densa, respectively. Laboratory-based tests were used to determine the larvicidal, adulticidal, oviposition deterrent, and half lethal dose (LD50) of each EO. Results. The concentrations of 100 μl/L and 50 μl/L resulted in complete mortalities of larvae and adults, respectively, for all the three Eos considered. The EOs exhibited high repellency with oviposition activity index of −1 (OAI = −1) at concentrations of 50 μl/L (Tar), 100 μl/L (Ala), and 200 μl/L (Yil). Conclusions. The EOs of T. serrulatus and T. schimperi were effective against larvae and adult mosquitoes at small doses and resulted in oviposition deterrence at doses from 50 to 200 μl/L. Thus, these EOs are promising mosquitocides and oviposition deterrents. But, further tests both in the presence of already known and effective deterrents and field trials are required

Antibacterial activity of essential oils from Ethiopian thyme (Thymus serrulatus and Thymus schimperi) against tooth decay bacteria.

In this study, we evaluated the antibacterial activities of the essential oils (EOs) of Thymus serrulatus and Thymus schimperi collected from Ofla (Ofl), Alamata (Ala), Yilmana Densa (Yil), Tarmaer (Tar), Butajira (Buta), and Bale (Bal) in Ethiopia against cariogenic bacteria (Streptococcus mutans and Lactobacillus) isolated from human teeth. Inhibition zones (IZs), minimum inhibitory concentrations (MICs), and minimum bactericidal concentrations (MBCs) were measures of the antibacterial activity. Significant bacterial inhibitions resulted in a dose-and EO-dependent manner. At 128 μl/mL, IZs against S. mutans were 37.33 mm (Tar), 36.00 mm (Bal), 33.67 mm (Yil), 33.33 mm (Ofl), 30.00 (Ala), and 29.67 mm (Buta) and IZs against Lactobacillus were 31.00 mm (Tar), 30.67 mm (Yil), 27.67 (Bal), 27.00 (Buta), 26.67 (Ofl), and 21.33 (Ala). The respective inhibition zones due to 3% DMSO (negative control) and 3% H2O2 (positive control) were 0.00 mm/30.00 mm against S. mutans and 0.00 mm/29.00 mm against Lactobacillus. At 128 μl/mL dose, all the EOs resulted in significantly higher inhibition zones than that of 3% H2O2 against S. mutans and Lactobacillus