Toxicological evaluation of chronic oral administration of Justicia schimperiana (Hochst. ex Nees) T. Anderson leaf 80% methanolic extract in Wistar albino rats

Background

Justicia schimperiana has been widely used for the treatment of various human ailments without scientific proof for chronic toxicity. Thus, this study is aimed to evaluate the chronic toxicity of 80% methanolic extracts of the leaves of Justicia schimperiana in rats.

Methods

An 80% crude methanolic extract of the plant leaves was orally administered to Wistar albino rats for 6 months. The experiment was conducted in accordance with the Organization for Economic Co-operation and Development's guideline number 452. Twenty rats per group and sex were randomly assigned to three treatment groups and a control group. Daily doses of 250 mg/kg, 500 mg/kg, and 1000 mg/kg of the extract diluted with distilled water were administered orally to the rats. Rats in the control group received distilled water orally. Weekly body weight and daily food intake were measured. At the end, rats were sacrificed for histopathological, biochemical and hematological tests. The statistical analysis was done using the Kruskal-Wallis test and one-way analysis of variance.

Results

Six months daily oral administration of the plant extract did not significantly affect the rats' food consumption, organ weight, and histopathology. Rats treated with 1000 mg/kg extract, however, significantly increased liver enzymes (aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase), and kidney function tests (creatinine and urea). Additionally, the high dose extract administered rats showed significantly lower red blood cell count, hemoglobin, and hematocrit compared to the control group.

Conclusion

Six months oral administration in Wistar albino rats in this experiment indicated that Justicia schimperiana is relatively safe at lower and medium doses. However, increased liver enzymes, increased kidney function tests and decreased red blood cell indices was observed in rats treated at higher doses. To obtain a thorough understanding of the plant's toxicity profile, it is advised that future studies be conducted on teratogenicity and reproductive toxicity.

Ethnomedicine, antibacterial activity, antioxidant potential and phytochemical screening of selected medicinal plants in Dibatie district, Metekel zone, western Ethiopia

BACKGROUND

Medicinal plants play a major role in the delivery of healthcare, particularly among the rural population of Ethiopia. Plant extracts and their bioactive compounds have been utilized for the treatment of several diseases. This study was aimed at evaluating the antibacterial activity, antioxidant capacity, and phytochemical content of selected medicinal plants used in Dibatie district, western Ethiopia.

METHODS

Study plants were collected, shade dried, pulverized, extracted by maceration in 80% ethanol, and subjected to antibacterial, antioxidant, and phytochemical tests. Minimum inhibitory concentration (MIC) was determined using 96-well microplates and nutrient broth microdilution. Antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. Phytochemical screening was conducted using standard test methods.

RESULTS

The ethanolic extract of Polystachya steudneri Rchb.f. pseudobulbs was the most active against gram-negative Proteus mirabilis, Salmonella typhimurium, Klebsiella pneumoniae, Escherichia coli, and Shigella flexneri, with MIC values of 8 ± 0, 11 ± 5, 3 ± 1, 3 ± 1, and 2 ± 0 mg/mL, respectively. The ethanolic extract of P. steudneri was also the most effective against gram-positive Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus agalactiae, and Enterococcus faecalis, with MIC values of 8 ± 0, 8 ± 0, 3 ± 1, and 16 ± 0 mg/mL, respectively. Ethanolic extracts of Gnidia involucrata Steud. ex A.Rich. stems and roots were effective antioxidants, with respective 50% DPPH free radical inhibitory concentrations (IC50) of 168.68 and 181.79 µg/mL, followed by that of P. steudneri (IC50 = 203.11 µg/mL). The study plants contained alkaloids, anthocyanins, anthraquinones, cardiac glycosides, coumarins, flavonoids, phenols, saponins, steroids, tannins, and terpenoids.

CONCLUSIONS

This study confirmed the antibiotic, antioxidant, and phytochemical constituents of the investigated plants and suggested further investigations that may lead to bioactive lead compounds.

Synthesis and antimicrobial activity of knipholone analogs

In the present study, we use knipholone as a prototype molecule to identify new anti-infective agents. Since knipholone is insoluble in water, which would have a detrimental effect on its bioavailability and efficacy, we synthesized knipholone Mannich base derivatives (2-4) that have better predicted solubility and investigated their in vitro antimicrobial activity against eight pathogenic bacterial and fungal strains. The chemical structures of compounds 1-4 were elucidated from their 1H and 13C NMR data, and their antimicrobial activity evaluation was carried out by a broth microdilution MTT assay. Compound 3 exhibited the strongest efficacy against Staphylococcus epidermidis, with MIC value of 9.7 µg/mL. While 4 exhibited the best activity against Staphylococcus aureus, with an MIC value of 19.5 µg/mL, and was the only one to significantly inhibit the fungus Trichophyton mentagrophytes (MIC = 78.2 µg/mL). The study provides evidence for the antibacterial activity of aminoalkyl derivatives of knipholone.

Antibacterial activity and phytochemical screening of traditional medicinal plants most preferred for treating infectious diseases in Habru District, North Wollo Zone, Amhara Region, Ethiopia

Ethiopia's healthcare system relies on traditional medicinal practices that use medicinal plants to treat human and livestock ailments. However, the lack of empirical validation regarding the efficacy of these treatments against specific infectious diseases necessitates rigorous scientific investigations. The objective of this study was to investigate the antibacterial activity and phytochemical screening on five selected medicinal plant species, namely Solanum somalense Franchet., Verbascum sinaiticum Benth., Rumex nervosus Vahl, Withania somnifera (L.) Dunal and Calpurnia aurea (Ait.) Benth. The plants were first identified jointly with local informants and later considering mainly their high informant consensus and fidelity level values for their efficacy in treating infectious diseases in the area. Ethanol and aqueous extracts were prepared from the plant materials, and their antibacterial activities were evaluated against standard bacterial strains, representing both gram-positive and gram-negative types. To assess the antibacterial activity of the extracts, the minimum inhibitory concentration (MIC) was determined using the broth dilution method. Additionally, phytochemical screening was performed using standard qualitative tests to identify various secondary metabolites. The results indicated antibacterial efficacy in the ethanol extracts of S. somalense, W. somnifera, and C. aurea against particular bacterial strains (S. somalense against S. agalactiae with MIC of 1.5 mg/mL; W. somnifera against S. aureus and E. coli, with MIC of 2 mg/mL; C. aurea against E. coli and K. pneumoniae, with MICs of 3 mg/mL and 3.5 mg/mL, respectively). The results of the phytochemical screening indicated the presence of steroids, alkaloids, flavonoids, saponins, and terpenoids. The selected medicinal plants demonstrated promising antibacterial activity against certain bacterial strains. The current findings support the long-standing claim of the traditional medical system of the study area for their continued use of these plants in their treatment of infectious diseases. Further investigation is required to isolate the responsible active compounds and characterize the constituents and description of their antibacterial effect for possible use in areas where these infectious diseases are major health problems.

Ethnoveterinary medicinal plants and their utilization by the people of Soro District, Hadiya Zone, southern Ethiopia

BACKGROUND

Ethnoveterinary studies are important to maintain the sustainability of livestock health and support people's livelihoods through the provision of food, maintaining livestock health, and other biological resources. This study was carried out in Soro District, southern Ethiopia, to identify, document and analyse plant species with ethnoveterinary uses along with the associated indigenous and local knowledge.

MATERIALS AND METHODS

Informants were selected using purposive (key informants) and systematic random sampling (general informants) methods. Data on ethnoveterinary plants and their uses were collected through semi-structured interviews, guided field walks, 13 focus group discussions with five to seven members in each and participant observation. Informant consensus factor and fidelity level were computed to identify the most common livestock ailment categories and the best plant species with ethnoveterinary use, respectively. Preference ranking methods were used to identify the potentially effective ethnoveterinary medicinal plants for the most frequently reported livestock ailments. The use diversity of multipurpose plants with ethnoveterinary importance was analysed using the analytical methods of ethnobotany including priority ranking, comparisons and important indices. The T-test statistic was used to compare knowledge differences among different social groups.

RESULTS

A total of 132 plant species in 120 genera and 61 families were reported by informants as having ethnoveterinary uses. The plants are said to be used by the local communities in various ways to treat 50 livestock health problems. Higher number of informants (23.77%) cited Momordica foetida for the treatment of 16 livestock ailments. The highest informant consensus value for this species is associated with its use for treating blackleg in cattle; Nicotiana tabacum was cited for the treatment of 15 livestock ailments mainly recommended for the Lumpy Skin Disease/Ailment of bovines; Croton macrostachyus for treatment of 13 livestock ailments including wooden tongue, FMD in bovines; and Gymnanthemum amygdalinum for nine ailments mainly diarrhoea of all livestock types. Achyranthes aspera is claimed to provide the most effective treatment for Aspiration pneumonia (severe coughing in bovines, sheep and goats) alone, while Croton macrostachyus, Ximenia americana, Allium sativum and Juniperus procera were indicated as potential plant species to treat Lumpy Skin Disease in bovines in the order given. The fidelity level analysis showed that Datura stramonium, Dodonaea viscosa subsp. angustifolia and Asparagus africanus were potential medicinal plant species to treat the respective ailments of rabies, Peste des petits ruminants (PPR) and evil eye/spirit. Multipurpose plant species including Prunus africanus, Combretum molle and Afrocarpus falcatus have been highly threatened as indicated by direct matrix ranking mainly due to collection of fuel wood, construction materials and making household utensils, and farm implements rather than for other uses.

CONCLUSION

Soro District has rich and diversified livestock herbal medicinal resources, and indigenous knowledge of remedy preparations and applications is transmitted through generation lines. This resource faces anthropogenic threats with deforestation being the leading factor. Consequently, ethnoveterinary medicinal plants continue to decline before adequate and proper scientific documentation and testing are made. There is a dire need for planning and implementation of appropriate in situ and ex situ conservation strategies and to strive towards ensuring the survival and sustainable utilization of such important plant resources of Soro District. This must be supported by further documentation of the associated indigenous knowledge and pharmacological testing of the key promising species including Balanites aegyptiaca (novel species/NS to treat specific ailment), Brugmansia suaveolens (novel species/NS reported first to treat Livestock ailments/LsAs), Euclea divinorum (NS to treat specific ailments), Grevillea robusta (NS), Hagenia abyssinica (NS for the reported specific ailment), Pentanema confertiflorum (NS), Juniperus procera (NS), Maesa lanceolata (NS), Millettia ferruginea (NS for reported specific ailments), Schrebera alata/NS, Securidaca longepedunculata, Spiniluma oxyacantha/NS, Vepris nobilis (novel species reported first to treat LsAs), Zanthoxylum asiaticum /NS and Ximenia americana (NS for specific ailments). This ethnoveterinary study attempted to fill part of the gaps concerning the prevalent livestock health problems and the associated indigenous and local knowledge in the area.

In vitro antimicrobial and antioxidant activities, essential oil composition, and in silico molecular modeling analysis of secondary metabolites from roots of Verbascum sinaiticum

Verbascum sinaiticum is locally used to treat wound, stomachache, viral infection, cancer, sunstroke fever, abdominal colic, diarrhea, hemorrhage, anthrax, and hepatitis. The objective of this study was to identify the compounds and to evaluate the antimicrobial and antioxidant activity of the extracts and isolated compounds from V. sinaiticum. The 1H-NMR, 13C-NMR, and DEPT-135 were used to elucidate the structures of isolated compounds. Essential oils were extracted by hydrodistillation method and their chemical analyses were performed by GC-MS. The broth microdilution method was used to evaluate the antimicrobial activity. The radical scavenging activity of the extracts and isolated compounds were evaluated using DPPH method. Silica gel column chromatographic separation of root extracts afforded seven known compounds: 3'-(4''-methoxy phenyl)-3'-oxo-propionyl hexadecanoate (1), harpagoside (2), pulverulentoside I (3), scrophuloside B4 (4), scropolioside A (5), scropolioside-D2 (6), and harpagide 6-O-β-glucoside (7), which are all reported from this species for the first time. The EO extracts from leaves and roots were the most susceptible to Streptococcus agalactiae, with a 2 mg/mL MIC. The EO from roots was effective against Candida albicans and Trichophyton mentagrophytes, with a MIC of 8 mg/mL. The MeOH and CH2Cl2/CH3OH (1:1) root extracts showed the maximum activity against S. epidermidis with MIC values of 0.25 mg/mL. The strongest antibacterial effects were demonstrated against Staphylococcus epidermidis, which exhibited a 0.0625 mg/mL MIC for compound 1. The strongest radical scavenging activity was exhibited by the methanol extract (IC50 = 3.4 μg/mL), and compounds 4, 6, 5, 3, 7, and 2 with IC50 values of 3.2, 3.38, 3.6, 3.8, 4.2, and 4.7 μg/mL, respectively, in comparison with ascorbic acid (IC50 = 1.3 μg/mL). The results of the molecular docking analysis of compounds revealed minimal binding energies range from -38.5 to -43.1 kJ/mol, -33.1 to -42.7 kJ/mol, -34.7 to -39.3.7 kJ/mol, -25.5 to -37.6 kJ/mol against human myeloperoxidase (PDB ID: 1DNU), murA enzyme (PDB ID: 1UAE), human topoisomerase IIβ (PDB ID: 4fm9), S. epidermidis FtsZ (PDB number: 4M8I) proteins, respectively. The docking results and the in vitro antibacterial activity are in good agreement. These findings show that the isolated compounds 2-7 can act as potential antioxidants and strong antibacterials against Staphylococcus aureus and S. epidermidis. As a result, V. sinaiticum root extracts have the potential to be effective in treating diseases caused by bacteria and free radicals, as long as further investigation has been suggested for the ultimate decision of this plant's potential candidate.

Evaluation of Anti-Inflammatory Activity of the Methanol Extracts of Premna schimperi Engl (Lamiaceae) Leaves in Rats

Background

Even though it is a protective reaction, inflammation continues to be one of the most challenging medical disorders. The current conventional anti-inflammatory drugs have many undesirable health effects and are in need of newer drugs. The purpose of this study was to evaluate the anti-inflammatory effects of an aqueous methanol crude extract of Premna schimperi leaves.

Methods

Premna schimperi leaf was extracted with 80% methanol and concentrated; the concentrated extract was used to evaluate the acute toxicity and anti-inflammatory effects. For the acute toxicity study, a single dose of Premna schimperi extract at a dose of 2000 mg/kg was administered and observed for 14 days. Acute, sub-acute, and chronic anti-inflammatory models were employed to evaluate the anti-inflammatory effect of the extract compared to the standard drug. Data were analyzed with SPSS V. 27, and the significance was established with a one-way ANOVA followed by a post hoc Tukey's test.

Results

Acute oral toxicity testing at a dose of 2000 mg/kg did not show any sign of toxicity. According to the phytochemical study, the plants contained flavonoids, terpenoids, tannins, cardiac glycosides, steroids, phenolics, and anthraquinones. The extract doses of 200 mg/kg, 400 mg/kg, and 800 mg/kg of extracts effectively (p<0.001) reduced paw edema in the acute and sub-acute models of inflammation. When compared to the negative control group, all tested doses in the chronic model significantly (p<0.05) decreased the production of exudates and the amount of granuloma tissue.

Conclusion

Premna schimperi displayed significant anti-inflammatory activity. The tested doses inhibit the formation of edema, granulomas, and exudates.

Antibacterial and phytochemical analysis of traditional medicinal plants: An alternative therapeutic Approach to conventional antibiotics

The purpose of this study was to carry out antibacterial and phytochemical analyses on six selected medicinal plants that have been traditionally used by the local people to treat and control different diseases. The antibacterial activities of methanolic extracts of these plants were assessed using the Agar well diffusion and Microtiter broth dilution methods. The root extract of Andrachne aspera showed significantly (p < 0.05) highest mean zone of inhibition at concentrations of 100 mg/ml (33 ± 0.17) and 200 mg/ml (33.5 ± 0.84) against S. epidermidis. The second highest mean zone of inhibition (24.8 ± 0.41) was recorded by Dichrostachys cinerea leaf extract against S. epidermidis at 200 mg/ml concentration. The minimum inhibitory concentrations 1.0 ± 0.0 was recorded by Andrachne aspera against E. faecalis and 2.0 ± 0.0 against S. aureus by Dichrostachys cinerea. The preliminary phytochemical analysis showed that Andrachne aspera and Dichrostachys cinerea contained strong concentration of Polyphenols and Flavonoids. Therefore, these two medicinal plant species have promising potential for further detailed investigations, including safety tests, characterization and isolation of bioactive secondary metabolites for the development of alternative drugs.

Antibacterial Activity of a Phenylpropanoid from the Root Extract of Carduus leptacanthus Fresen

Background

The emergence and rapid spread of antimicrobial drug-resistance microorganisms exacerbate the treatment of infectious diseases, underscoring the importance of finding new, safe, and effective drugs. In Ethiopia, the roots of Carduus leptacanthus have traditionally been employed to treat microbial infectious diseases The aim of this study was to evaluate the antibacterial activity of the root extract and its primary components against six bacterial strains (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus agalactiae, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumonia).

Methods

The extraction involved maceration of air-dried and powdered roots of C. leptacanthus with 80% methanol. The compound was isolated from the root extract using silica gel column chromatography and recrystallization in CHCl3/MeOH (9 : 1) and was characterized using ESI-MS and 1D-NMR spectroscopy. Antibacterial activity of the extract was assessed using agar well diffusion and broth microdilution methods.

Results

Syringin, a phenylpropanoid, was isolated and characterized from the extract of C. leptacanthus. The extract showed the most substantial efficacy against S. epidermidis (MIC = 5.33 mg/ml and inhibition zone diameter of 24 mm at 200 mg/m). Syringin also elicited antibacterial activity against S. aureus (MIC = 13.33 mg/ml), S. epidermidis (MIC = 16 mg/ml), and S. agalactiae (MIC = 16 mg/ml). Despite being tested up to a maximum concentration of 16 mg/ml, syringin did not exhibit antibacterial activity against the Gram-negative bacteria (P. aeruginosa, E. coli, and K. pneumonia).

Conclusions

In conclusion, the findings suggest that syringin exhibits partial involvement in the root extract's antibacterial activity, thereby potentially supporting the traditional medicinal use of the plant.

Acute and developmental toxicity of embelin isolated from Embelia schimperi Vatke fruit: In vivo and in silico studies

Background

Embelin is a hydroxybenzoquinone constituent of the Embelia species that has anti-disease properties. However, its toxicity, particularly the in silico, acute, and developmental toxicity profiles, has yet to be thoroughly investigated. Hence, this study aims to assess these toxicity profiles.

Materials and Methods

In silico and in vivo experimental studies were conducted on embelin isolated from the fruits of Embelia schimperi Vatke. In silico toxicity predictions were computed using the ProTox model. The in vivo experiment was done by administering 5000 mg/kg of embelin to a single female albino Wistar rat, followed by three female rats in the absence of death, to determine the mean lethal dose (LD50). Afterwards, three groups of pregnant rats were treated with embelin at doses of 250 mg/kg, 500 mg/kg, and 1000 mg/kg for the developmental toxicity test. Vehicle and ad libitum control groups were used to compare the acute and developmental toxicity variables.

Results

In silico toxicity predicted that embelin is free from hepatotoxic, carcinogenic, mutagenic, and cytotoxic effects. No inhibitory effect on hERG channels was observed. It has an immunotoxic property and an inhibitory effect on the CYP2D6 enzyme. Since mortality and signs of toxicities were not observed after treatment with 5000 mg/kg, the mean lethal dose (LD₅₀) is determined to be > 5000 mg/kg. There was no significant difference in the morphological scores or number of somites among experimental animals. None of the embryonic systems possessed developmental delays. Nevertheless, the crown-rump length of the high-dose group became significantly shorter. Maternal food intake and weight gain exhibited significant dose-dependent differences between embelin-treated animals and controls. The number of implantations was significantly low in the treatment group, accompanied by a higher frequency of prior resorption.

Conclusion

Embelin is predicted to have a high probability of immunotoxicity potential and affect drug metabolism by inhibiting CYP2D6. In addition, it affects food intake, weight gain, and the number of implantations in pregnant rats. Therefore, it is highly recommended not to take embelin and embelin-rich plants during pregnancy. Further in vitro and in vivo studies need to be conducted to understand the mechanism behind the toxicity of embelin.

Toxic effect of Syzygium guineense ethanolic extract on female reproduction in rats: An evidence from a 10 week repeated-dose toxicity study

Introduction

It has been reported that some herbal products affect reproduction. To date, reproductive toxicity of Syzygium guineense has not been investigated although the plant is widely used in treating fertility related problems. Thus, the objective of the current study was to investigate the toxic effects of 70% ethanol extract of S. guineense leaves on the reproductive function and histopathology of reproductive organs in female rats.

Methods

Eighty female Wistar albino rats were randomly divided into four groups where each group consisted of 20 rats. Rats in the first three groups were treated with S. guineense extract at doses of 250, 500 and 1000 mg/kg body weight, respectively. The fourth group served as a control group. The rats were treated for ten consecutive weeks. The length of estrous cycle, reproductive indices, pregnancy outcomes, and number of postnatal deaths were recorded. At necropsy, organ weight was measured, gross and histopathological examinations of ovaries, uterus, and vagina were conducted.

Results

Treatment of rats, with high dose (1000 mg/kg) of S. guineense, significantly prolonged the duration of estrous cycle and reduced weight of uterus and ovaries as well as the number of total and live birth pups. However, there were no significant changes observed in reproductive indices and gross morphology as well as histopathology of ovaries, uterus, and vagina.

Conclusion

Administration of high doses of S. guineense could be toxic to some aspects of the reproductive system of female rats and might also affect reproduction. Therefore, consuming high dose of S. guineense leaves is not recommended.

Toxic effects of 70% ethanol extract of Moringa stenopetala leaf (Baker f.) Cufod. (Moringaceae) on fetus and placenta of pregnant Wistar rats

BACKGROUND

Moringa stenopetala leaves (Baker f.) Cufod. (Moringaceae) are used as a staple food and traditional medicine for treating various diseases like malaria, hypertension, stomach pain, diabetes, elevated cholesterol, and removing the retained placenta. Its prenatal toxicity study is minimal. Thus, this study aimed to assess the toxic effects of a 70% ethanol extract of Moringa stenopetala leaf on the fetuses and placentas of pregnant Wistar rats.

METHOD

Fresh leaves of Moringa stenopetala were collected, dried at room temperature, ground to powder, and extracted using 70% ethanol. For this study, five groups of animals, each containing ten pregnant rats, were used. Groups I-III were experimental groups and treated with 250, 500, and 1000 mg/kg body weight of Moringa stenopetala leaf extract, respectively. Groups IV and V were pair-fed and ad libitum control groups. The extract was given during gestation days 6 to 12. The fetuses were recovered at day 20 of gestation and examined for the presence of developmental delays, gross external malformations, skeletal and visceral defects. Gross and histopathological changes in the placenta were also evaluated.

RESULTS

Compared to the pair-fed control group, maternal daily food intake and weight gain were reduced in the 1000 mg/kg-treated group during the treatment and post-treatment periods. A significantly higher number of fetal resorptions was also seen in the 1000 mg/kg treatment group. The crown-rump length and fetal and placental weights were all significantly reduced in pregnant rats given 1000 mg/kg. However, there were no visible malformations in the visceral organs as well as external genitalia in all the treatment and control groups. About 40.7% of the fetuses in the 1000 mg/kg treated rats had no proximal hindlimb phalanges. In addition, light microscopic investigations of the placenta in the high-dose treated rats revealed structural changes in the decidual basalis, trophoblastic zone, and labyrinthine zones.

CONCLUSION

In conclusion, consumption of M. stenopetala leaves at a higher dose may have toxic effects on the development of rat fetuses. At a higher dose, the plant extract increased the number of fetal resorptions, reduced the number of fetuses, decreased the fetal and placental weights, and alter the placental histopathology. Thus, it is recommended to limit the excess feeding of M. stenopetala leaves during gestation.

Analgesic and Anti-Inflammatory Activities of 80% Methanol Extract and Solvent Fractions of Ehretia cymosa Thonn (Boraginaceae) Leaves in Rodents

Background

Ethnobotanical studies in various districts of Ethiopia reported that Ehretia cymosa (E. cymosa) is used for the management of headache, abdominal pain, arthritis and rheumatism. However, there is no scientific investigation done so far to confirm these traditional claims. Thus, the aim of this study was to assess the analgesic and anti-inflammatory effects of the 80% methanol extract and fractions of E. cymosa leaves.

Methods

The dried and pulverized leaves of E. cymosa were soaked with 80% methanol to obtain a crude extract. Fractionation was done using chloroform, ethyl acetate and water by a soxhlet apparatus. The analgesic effects of the crude extract and solvent fractions were assessed using acetic acid-induced writhing and hot plate tests whereas anti-inflammatory activities were investigated using carrageenan-induced paw edema and cotton-pellet-induced granuloma models.

Results

In all the tested doses, the 80% methanol extract and solvent fractions revealed substantial (p < 0.001) analgesic activities in acetic acid induced writhing test. In the hot plate method, all the tested doses of E. cymosa crude extract and the solvent fractions produced significant analgesic activities (p < 0.05). In the carrageenan-induced acute inflammation model, all tested doses of the crude extract and solvent fractions resulted in a significant decline in paw edema. The 80% methanol extract and solvent fractions of E. cymosa at all the tested doses significantly reduced inflammatory exudates and granuloma mass formations (p < 0.001).

Conclusion

From the results of this investigation, it can be stated that 80% methanol extract, aqueous, ethyl acetate and chloroform fractions of E. cymosa exhibited considerable analgesic and anti-inflammatory activities, supporting the plant's traditional use as a remedy for a variety of painful and inflammatory conditions.

Predicting the long-term impact of rotavirus vaccination in 112 countries from 2006 to 2034: A transmission modeling analysis

Rotavirus vaccination has been shown to reduce rotavirus burden in many countries, but the long-term magnitude of vaccine impacts is unclear, particularly in low-income countries. We use a transmission model to estimate the long-term impact of rotavirus vaccination on deaths and disability adjusted life years (DALYs) from 2006 to 2034 for 112 low- and middle-income countries. We also explore the predicted effectiveness of a one- vs two- dose series and the relative contribution of direct vs indirect effects to overall impacts. To validate the model, we compare predicted percent reductions in severe rotavirus cases with the percent reduction in rotavirus positivity among gastroenteritis hospital admissions for 10 countries with pre- and post-vaccine introduction data. We estimate that vaccination would reduce deaths from rotavirus by 49.1 % (95 % UI: 46.6-54.3 %) by 2034 under realistic coverage scenarios, compared to a scenario without vaccination. Most of this benefit is due to direct benefit to vaccinated individuals (explaining 69-97 % of the overall impact), but indirect protection also appears to enhance impacts. We find that a one-dose schedule would only be about 57 % as effective as a two-dose schedule 12 years after vaccine introduction. Our model closely reproduced observed reductions in rotavirus positivity in the first few years after vaccine introduction in select countries. Rotavirus vaccination is likely to have a substantial impact on rotavirus gastroenteritis and its mortality burden. To sustain this benefit, the complete series of doses is needed.

Evaluation of Wound Healing and Anti-Inflammatory Activity of Hydroalcoholic Leaf Extract of Clematis simensis Fresen (Ranunculaceae)

Introduction

Clematis simensis is one of the most widely used medicinal plant for the treatment of wound traditionally. However, its claim was not scientifically tested, the current study therefore assessed the anti-inflammatory and wound healing properties of 80% methanol leaf extract of C. simensis.

Methods

The dried and powdered leaf of C. simensis was macerated with 80% methanol. The topical ointment was then made in two concentrations (5% and 10% w/w), and two models, excision and incision, were used to test the extract's capacity to treat wounds in mice. In addition, anti-inflammatory test was also conducted using carrageenan-induced hind paw edema model in three doses (100, 200, and 400 mg/kg) in rats. The DPPH test was used to determine the extract's anti-oxidant properties where ascorbic acid was used as standard agent.

Results

When wounds were treated with ointments containing 5% and 10% (w/w) extract, the rate of wound contraction, the length of time it took for the epithelium to form, and the strength of the skin to break were all significantly increased (p < 0.05). There was no discernible difference in wound healing activity between the 10% (w/w) and 5% (w/w) extracts. Moreover, they had also similar impact as that of the positive control nitrofurazone in wound healing activity. Compared to the negative control, C. simensis extract considerably (p < 0.01-p < 0.001) reduced inflammation. The extract also demonstrated antioxidant activity with IC50 values of 0.7 mg/mL for the extract and 1.04 mg/mL for ascorbic acid, respectively.

Conclusion

Overall, it is plausible to draw the conclusion that C. simensis 80% methanol extract possesses wound healing activity, perhaps as a result of its anti-inflammatory and antioxidant effects.

Evaluation of antibacterial and acute oral toxicity of Impatiens tinctoria A. Rich root extracts

The high prevalence of morbidity and mortality from bacterial infections, together with the growing threat of antibacterial resistance, necessitated the development of alternative new drugs from traditional medicine. In Ethiopia, Impatiens tinctoria A. Rich has been traditionally used for the treatment of fungal infections such as ringworms that cause tinea pedis and it have also different medical values. Scientific information on its biological activity against a broad range of bacteria and safety data is scant, compared to its folklore data. In this study, we evaluated antibacterial activities and acute oral toxicity of aqueous, ethanol and ethyl acetate root extracts of Impatiens tinctoria A. Rich. Aqueous, ethanol and ethyl acetate extracts of the plant were evaluated using agar hole diffusion and agar dilution methods. Biological activities of the plant extracts were expressed as a zone of inhibition diameter, minimum inhibitory concentration (mg/ml), and minimum bactericidal concentration (mg/ml). The safety studies were performed by oral acute toxicity study according to the organization of economic cooperation and development test Guidelines 420.Gram-positive bacteria were more susceptible to the extracts compared to gram-negative bacteria, especially against S. aureus and S. epidermidis, which are commonly found in the skin. Ethyl acetate extract was more potent than ethanol and aqueous extracts. The 50% lethal dose (LD50) of tested mice was above 9600 mg/kg. This study provides a scientific basis for the antibacterial activity of the root extracts of I. tinctoria A. Rich, where, the ethyl acetate extract showed the most promising activity. Therefore, the antibacterial potential and practical non-toxicity of the study plant extracts suggested the possibility of using it for the development of antimicrobial drugs by further studying the plant in different directions.

Intestinal parasitic infections and associated factors among pregnant women in Ethiopia: a systematic review and meta-analysis

Background

Intestinal parasitic infections (IPIs) are public health problems widely distributed in the world and cause significant morbidity and mortality; many of which occur among women of reproductive age. IPIs caused by helminthes and protozoan parasites are common among pregnant women. Data on the national pooled prevalence of intestinal parasites and associated factors during pregnancy is not documented well in Ethiopia. This review aims at summarizing evidences on the burden of IPIs and associated factors among pregnant women in Ethiopia.

Methods

Published and unpublished studies were thoroughly searched at MEDLINE/PubMed, EMBASE, Google Scholar, CINAHL, Cochrane library and Science Direct. In addition, repositories of Addis Ababa, Gondar and Jimma Universities were searched. Eligible studies were selected following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline. The pooled prevalence of intestinal parasites and summary odds ratios (ORs) were determined with 95 % confidence intervals (CI). Sub-groups analyses were done based on study region, types of parasites, methods of stool examination and study setting. The statistical analyses were performed using STATA version 14.0 software.

Results

Among 168 retrieved studies, 31 studies with a total population of 12,118 pregnant women were included. The estimated pooled prevalence of IPIs among pregnant women in Ethiopia was 27.32 % (95 % CI: 20.61, 33.87 %). In the subgroup analysis, Oromia and Amhara regions had the highest prevalence with a 29.78 % (95 % CI: 15.97, 43.60) and 29.63 % (95 % CI: 15.37, 43.89); respectively. In addition, studies conducted in the community showed higher prevalence than institution based studies (49.93 % Vs 24.84 %; respectively). The most prevalent type of intestinal parasite identified were Hookworm followed by Ascaris lumbricoides with a pooled prevalence of 11.2 and 10.34 %, respectively. In our analysis; residence, being bare footed, lack of hand washing habit and eating uncooked/raw vegetables were significantly associated with IPIs among pregnant women in Ethiopia.

Conclusions

Prevalence of IPIs during pregnancy is relatively high in Ethiopia. Poor hygienic practices were identified as risk factors. Based on our finding, targeted preventive measures shall be considered so as to prevent morbidity and mortality due to IPIs.

Sub-chronic toxicity of ethanol leaf extract of Syzygium guineense on the biochemical parameters and histopathology of liver and kidney in the rats

•

Long-term use of Syzygium guineense leaf extract reduced the food intake and weight gain in rats.

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The serum level of liver and kidney enzymes of rats was increased by the treatment of high dose of Syzygium guineense leaf.

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Use of Syzygium guineense leaf extract showed hypoglycemic effect in rats.

Background

Syzygium guineense Wall. leaf is being used as a traditional medicine against hypertension and diabetes mellitus. Unlike its efficacy, the safety profile of this plant upon long-term administration has not been investigated yet. Therefore, this study investigated the sub-chronic toxicity of S. guineense leaves in rats.

Methods

Wistar albino rats, 10/sex/group were randomly assigned into four groups. Group I-III respectively received 250, 500, and 1000 mg/kg of body weight of 70 % ethanol extract ofS. guineense leaves for 90 consecutive days. Group IV (control) received distilled water. Throughout the experiment, clinical observations were carried out, food intake and weight of the rats also were measured. Finally, different biochemical parameters, organ weight, and histopathology of liver and kidneys were evaluated.

Results

Administration of 70 % ethanol extract ofS. guineense leaves decreased food intake and body weight gain of the test animals. Rats treated with 1000 mg/kg of S. guineense extract showed significantly increased serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase levels. Serum urea levels also increased in female rats treated with 500 and 1000 mg/kg body weight of S. guineense. Moreover, the blood glucose level of rats treated with 1000 mg/kg body weight was significantly decreased compared to the control group. However, the histology of the liver and kidneys were not significantly altered by any of the doses administered.

Conclusion

Administration ofS. guineense in rats at a dose of 1000 mg/kg body weight affected the food consumption, weight gain, and serum levels of liver and kidney enzymes suggesting that S. guineense intake at high doses may be toxic. Therefore, liberal consumption of S. guineense leaves should be taken curiously and cautiously.

Methanol (80%) leaf extract of Otostegia integrifolia Benth (Lamiaceae) lowers blood pressure in rats through interference with calcium conductance

Background

Otostegia integrifolia Benth. (Lamiaceae) leaves are used to treat hypertension in Ethiopian folk medicine. However, the claim has so far not been investigated scientifically. Thus, the objective of this study was to evaluate the antihypertensive activity of 80% methanol leaf extract of O. integrifolia in animal model of hypertension and possible underlying mechanisms in isolated rat aorta.

Methods

Antihypertensive effect of various oral doses of the extract (250, 500 and 1000 mg/kg) was determined in fructose-induced hypertensive rats using the non-invasive tail-cuff method. Thoracic aortic strips of rats were isolated and suspended in organ bath, and the vasodepressor effect as well as the possible mechanism (s) of action were studied by means of isometric tension recording experiments ex vivo. Phytochemical analysis was also performed to suggest possible constituents related to the activity.

Results

Blood pressure was significantly lowered in a dose-dependent manner following extract administration, suggesting that the extract possesses antihypertensive activity. The extract also caused a dose-dependent relaxation of aortic strip precontracted with KCl at a concentration of 6.25–125 μg/L, with a maximum relaxation (100%) achieved at a cumulative concentration of 318.75 μg/ml. The relaxation mechanism was found to be independent of muscarinic receptors, prostanoids, histamine receptors, ATP dependent K⁺ channels, sarcoplasmic reticulum stored Ca²⁺ and the endothelium system. The extract shifted the Ca²⁺ concentration-response curve to the right similar to that caused by nifedipine, suggesting that vasorelaxation could possibly be mediated via calcium channel blockade. The extract was found to contain phenolic compounds (164.3 mg/g, expressed as gallic acid equivalents) and flavonoids (125.7 mg/g, expressed as quercetin equivalents).

Conclusion

The findings revealed that the plant is endowed with antihypertensive activity, providing evidence for its traditional use. The effect maybe, at least in part, due to dilation of blood vessels through blockade of Ca^+ 2 channels mediated by phenolic and flavonoid constituents.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03222-4.

Evaluation of Antihyperglycemic Effect of Extract of Moringa stenopetala (Baker f.) Aqueous Leaves on Alloxan-Induced Diabetic Rats

BACKGROUND

Diabetes is a serious metabolic disorder with complications that result in significant morbidity and mortality. Current drugs used for diabetes therapy are not free from side effects and do not restore normal glucose homeostasis. Therefore, the purpose of this study is to evaluate the antidiabetic effect of Moringa stenopetala (Baker f.) aqueous leaves extract.

METHODS

Thirty rats of weight 90-150 gram were distributed to five groups (n= 6). Then labelled as diabetic control (DC), normal control (NC), extract treated (MS 250 and 500mg/kg), and glibenclamide treated (GL 5mg/kg). The experimental rats were induced by intra-peritoneal injection of Alloxan monohydrate at a dose of 180 mg/kg after dissolving in normal saline. Clinical biochemistry such as AST, ALT, ALP, urea, creatinine, and cholesterol, blood glucose level, histopathological and preliminary phytochemical screening were evaluated.

RESULTS

Phytochemical tests revealed the presence of different secondary metabolites. Alkaloid, flavonoid, tannin, saponin, phytosteroids, phenols and terpenoids. Moringa stenopetala (Baker f.) leaves aqueous extract (250 and 500mg/kg) improved the body weight of rats, showed remarkable reduction in blood glucose concentration (P<0.05), and significantly decreased serum urea, creatinine, ALT, AST and ALP (P < 0.05). Levels of serum cholesterol remained unaltered in the experimental groups when compared with diabetic control. Histopathology of non-treated rats showed deterioration of insulin producing pancreas cells; nevertheless, β-cells restoration was observed due to administration of Moringa stenopetala (Baker f.) aqueous leaves extract.

CONCLUSION

It is possible to conclude that oral administration of Moringa stenopetala (Baker f.) aqueous leaf extracts (250mg/kg and 500mg/kg) for 28 days showed beneficial effects on antihyperglycemia, improved body weight and Alloxan damaged pancreatic β-cells, and restored biochemical changes.

Acute and sub-acute toxicity of Echinops kebericho decoction in rats

BACKGROUND

Echinops kebericho is widely used for treatment of a variety of diseases including infectious, non-infectious disease and fumigation during child birth. Antibacterial, antimalarial, anti-leshimania, anti-diarrheal and insect repellent activities have been elucidated. Its toxicity profile is not yet investigated and thus this study was to investigate acute and sub-acute toxicity of E. kebericho decoctions.

METHODS

Acute toxicity study was performed in female Wistar albino rats with single oral dose and followed up to 14 days. The sub-acute oral dose toxicity studies were conducted in rats of both sexes in accordance with the repeated dose 28-day oral toxicity study in rodent OECD guidelines. Physical observations were made regularly during the study period while body weight was measured weekly. Organ weight, histopathology, clinical chemistry and hematology data were collected on the 29th day. Results were presented as mean ± standard deviation. One-way analysis of variance (ANOVA) was performed if assumptions were met; otherwise Kruskal-Wallis analysis was performed.

RESULT

Oral administration of E. kebericho decoction showed no treatment-related mortality in female rats up to the dose of 5000 mg/kg. In sub-acute toxicity studies, no significant treatment-related abnormalities were observed compared to negative controls. Food consumption, body weight, organ weight, hematology, clinical chemistry, and histopathology did not show significant variation between controls and treatment groups. However, creatinine, relative lung weight, triglycerides, and monocytes were lower in treated compared to control groups. Significant variations between male and female groups in food consumption, relative organ weight, hematology, clinical chemistry were observed. Histolo-pathology of high-dose treated groups showed fatty liver.

CONCLUSION

Echinops kebericho showed LD₅₀ of greater than 5000 mg/kg in acute toxicity study and is well tolerated up to the dose of 600 mg/kg body weight in sub-acute toxicity study.

In vitro vasodilatory activity and possible mechanisms of the crude extracts and fractions of Moringa stenopetala (Baker f.) Cufod. leaves in isolated thoracic aorta of guinea pigs

Moringa stenopetala, a plant belonging to the family of Moringaceae, is traditionally used for the treatment of hypertension and diabetes in Ethiopia. This study evaluates the in vitro vasodilatory effect of the extract of M. stenopetala leaves and the possible mechanisms in precontracted isolated thoracic aorta of guinea pigs. A guinea pig was sacrificed by gentle cervical dislocation, and the thoracic aortic ring was removed, cut spirally, and mounted in an organ bath containing Krebs-Henseleit physiological solution maintained at 37°C, and then the solution was aerated with carbogen (95% O₂ and 5% CO₂). The vasodilatory activity of cumulative doses of M. stenopetala extracts and fractions was evaluated on intact and denuded endothelium of isolated whole, spirally cut thoracic aortic strips of guinea pigs precontracted with potassium chloride (80 mM), epinephrine (1 μM), methylene blue (10 μM), and glibenclamide (10 μM) using polygraph. All extracts showed a relaxant effect in precontracted isolated whole, spirally cut thoracic aortic strips of guinea pigs in a dose-dependent manner, whereas the greater percentage of relaxant effect was shown with the addition of crude extracts in 80 mM of potassium chloride (99.10% and 95.56% for ethanol and aqueous crude extracts, respectively), and 1 μM of epinephrine (82.85% and 90.16% for ethanol and aqueous crude extracts, respectively) in precontracted isolated whole, spirally cut thoracic aortic strips of guinea pigs. Hence, the possible mechanism of relaxation might be mediated through the blockade of receptor-operated calcium influx and L-type voltage-dependent calcium channels. The aqueous extract showed more significant in vitro vasodilatory effect than its fractions and 70% ethanol extract.

Evaluation of anthelmintic potential of the Ethiopian medicinal plant Embelia schimperi Vatke in vivo and in vitro against some intestinal parasites

Background

Embelia schimperi has been used for the treatment of intestinal parasites especially tapeworm infestations for centuries in Ethiopia. However, there is lack of scientific based evidences regarding the efficacy, safety and phytochemical analysis of this plant despite its frequent use as an anthelmintic. This study has therefore evaluated the efficacy and acute toxicity of E. schimperi thereby generating relevant preclinical information.

Methods

The anthelmintic activities of the crude hydroalcoholic extract of E. schimperi and the isolated compound, embelin, were conducted using in vivo and in vitro models against the dwarf tapeworm, Hymenolepis nana, and the hookworm, Necator americanus, respectively. LD₅₀ of the crude hydroalcoholic extract was determined using Swiss albino mice following the OECD guidelines. Chemical characterization of the isolated embelin was conducted using UV-spectroscopy, HPLC and NMR.

Results

In the acute toxicity study no prominent signs of toxicity and mortality were recorded among the experimental animals at the highest administered dose. Hence the LD₅₀ of the plant was found to be higher than 5000 mg/kg. In vivo cestocidal activity of the crude hydroalcoholic extract of E. schimperi showed 100 % parasite clearance at 1000 mg/kg, while the diammonium salt of embelin showed 85.3 % parasite clearance at 750 mg/kg. The in vitro anthelminthic activity study revealed that the LC₅₀ value of the crude extract and albendazole were 228.7 and 51.33 μg/mL, respectively.

Conclusion

The results clearly indicated that the hydroalcoholic extract of E. schimperi and the diammonium salt of the isolated compound embelin had anthelmintic activity against hookworm larva in vitro and H. nana in vivo. Hence the findings of this study showed Embelia schimperi appears to possess some anthelmintic activity that may support the usage of these plants by local traditional healers to treat helminthic infestations.

Estimation of bioavailability of DL-methionine hydroxy analogue relative to DL-methionine in layers with exponential and slope-ratio models

An experiment was conducted using molted hens to estimate the bioavailability of DL-methionine hydroxy analogue-free acid (MHA-FA) relative to DL-methionine (DLM). In this experiment, 5 supplemental levels (0.012, 0.024, 0.036, 0.048, and 0.060%) of DLM or equimolar concentrations of MHA-FA were added to a basal diet containing 14.97% protein and 0.27% methionine. The low protein diet was used to increase the sensitivity of laying hens to methionine deficiency. Feed consumption, egg production, egg mass, and egg weight increased (P < 0.05), and feed conversion decreased (P < 0.05) when DLM or MHA-FA was added to the basal diet for some supplemental methionine levels. There was no difference (P > 0.05) in feed consumption between hens fed DLM and hens fed MHA-FA. Regression analysis showed that the bioavailability of MHA-FA relative to DLM on a molar basis was 88.7% (egg production), 88.0% (egg mass), and 84.6% (egg weight) with the exponential model, and was 89.7% (egg production), 89.6% (egg mass), and 86.8% (egg weight) with the slope-ratio model. The average bioavailability of MHA-FA relative to DLM was 88% on a molar basis.

Seroepidemiology of hepatitis B virus in Addis Ababa, Ethiopia: transmission patterns and vaccine control

A community-based seroepidemiological survey of Addis Ababa, Ethiopia was conducted in 1994 to inform on the transmission dynamics and control of hepatitis B virus (HBV) infection. Venous blood from 4736 individuals under 50 years of age from 1262 households, selected using stratified cluster-sampling, was screened for HBV markers using commercial ELISAs. HBsAg prevalence was 7% (95 % CI 6-8), higher in males (9%; 7-10) than females (5%; 4-6). HBeAg prevalence in HBsAg positives was 23% (18-29), and less than 1% of women of childbearing age were HBeAg positive. Overall HBV seroprevalence (any marker), rose steadily with age to over 70% in 40-49 year olds, indicating significant childhood and adult transmission. Estimated instantaneous incidence was 3-4/100 susceptibles/year, higher in males than females in 0-4 year olds, and peaking in early childhood and young adults. The age at which 50% had evidence of infection was around 20 years, and the herd immunity threshold is approximated at 63-77%. Addis Ababa is of intermediate-high HBV endemicity, with negligible perinatal transmission. Our main findings are the identification of a significant difference between males and females in the age-acquisition of HBV infection, and marked differences between age groups in HBV incidence rates. These results should target future research studies of underlying risk factors. Furthermore, we generate a crude estimate of the level of coverage of HBV vaccine that would be required to eliminate the virus from the study population.

Seroepidemiology of measles in Addis Ababa, Ethiopia: implications for control through vaccination

We undertook a representative survey of measles antibodies in Addis Ababa, Ethiopia 1994, to characterize immunity and transmission. Specific-antibody levels (IU/l) were determined by ELISA for 4654 sera from individuals aged 0-49 years (1805 < 15 years) collected by stratified household-cluster sampling. The proportion seronegative (< 100 IU/l) was 20% (95% CI: 16-25) in children 9-59 months old, declining to 9% (7-12) in 5-9 year olds, 5% (4-7) in 10-14 year olds, and < 1% in adults. The proportion of children (< 15 years old) with low-level antibody (100-255 IU/l) was 8% (7-10). Vaccination and an absence of a history of measles illness were strongly associated with low-level antibody. History of measles vaccination in 9 months to 14-year-old children was approximately 80%. We estimate a primary vaccine failure rate of 21% (12-34) and continued high measles incidence of 22 per 100 susceptibles (19-24) per annum. Our data support the introduction of campaign vaccination in the city in 1998, although higher routine vaccine coverage is required to sustain the impact. The implications of a high prevalence of low-level antibody are discussed.

Timing of the HIV-1 subtype C epidemic in Ethiopia based on early virus strains and subsequent virus diversification

OBJECTIVE

To trace the introduction of HIV-1 subtype C into Ethiopia based on virus diversification during the epidemic.

DESIGN

A set of 474 serum samples obtained in Ethiopia in 1982-1985 was tested for HIV-1. HIV-1 env gp120 V3 and gag or pol regions were sequenced and analysed together with sequences from later stages of the epidemic.

RESULTS

None of 98 samples from 1982-1983, one of 193 samples from 1984, and one of 183 samples from 1985 were HIV-1 positive. Phylogenetic analysis of virus sequences from positive samples revealed that they belong to the Ethiopian C, and not the C', cluster. Analysis of 81 Ethiopian C V3 sequences from 1984-1997 revealed that the consensus sequence of the Ethiopian epidemic has been stable over time. Both the 1984 and 1985 V3 sequences, in contrast with three out of 27 (11%) of the 1988 and none out of 51 of the 1992-1997 sequences, had no synonymous substitutions compared to the reconstructed common ancestor of the Ethiopian C viruses. A highly significant correlation between sampling years of the V3 sequences and their synonymous distances to the common ancestor was demonstrated.

CONCLUSIONS

The increasing genetic heterogeneity together with stable consensus sequence of the Ethiopian HIV-1 C population demonstrates that evolution of the virus population is characterized by an unbiased expansion around a stationary consensus. Based on the rate of synonymous diversification of HIV-1 strains within the Ethiopian population, we were able to estimate 1983 (95% confidence interval, 1980-1984) as the year of HIV-1 C introduction into Ethiopia.

Timing of the introduction into Ethiopia of subcluster C' of HIV type 1 subtype C

Viruses circulating in Ethiopia during the 1990s cluster with main subtype C, but a significant subcluster, C', was noted in multiple analyses. This subcluster of subtype C(C') was in a fifty-fifty equilibrium with the main subtype C (Abebe et al., AIDS Res Hum Retroviruses 2000;16:1909-1914). To analyze genetic diversification within the subcluster of HIV-1 subtype C designated C' in the course of the epidemic in Ethiopia, we analyzed 165 env gp120 V3 sequences obtained between 1988 and 1999. We observed a highly significant positive correlation between sampling years of individual sequences and their synonymous distances to the reconstructed common ancestor of the HIV-1 subtype C' subcluster. The extrapolation of the regression line of synonymous distances back to the date when no synonymous heterogeneity was present among the Ethiopian HIV-1 C' population allowed us to estimate 1982 (95% CI, 1980-1983) as the year of the onset of HIV-1 C' genetic diversification and expansion in Ethiopia. These results are in agreement with retrospective epidemiological and serological data, which demonstrated the absence of an HIV-1 epidemic in the Ethiopian population before the 1980s.

Identification of a genetic subcluster of HIV type 1 subtype C (C') widespread in Ethiopia

Others and we have previously shown that subtype C is the predominant HIV-1 subtype and the major cause of AIDS in Ethiopia. The present study shows that subtype C in Ethiopia has a genetic subcluster, designated C', has not increased in frequency, or spread geographically, over the period 1988 (%C' = 23/53) to 1996-1997 (%C' = 26/50). There is no association of the HIV-1 subtype C or subcluster C' with geographic location, time of sample collection, or risk group in Ethiopia. Of 105 randomly collected samples representing 7 different towns in Ethiopia, all but 2 (1 subtype A from Addis Ababa, 1997 and 1 subtype D from Dessie, 1996) belong to subtype C.

Sero-epidemiology of rubella in the urban population of Addis Ababa, Ethiopia

We conducted a community-based cluster sample survey of rubella sero-epidemiology in Addis Ababa, Ethiopia in 1994. Among 4666 individuals for whom complete data were available, rubella antibody prevalence was 91% (95% confidence interval: 90, 92). On multivariable analysis, seroprevalence was lower among individuals who were resident in Addis Ababa for 1 year or less. Approx. 50% seroprevalence was attained by age 4 years, and the estimated average age at infection was 5.2 years. The highest age-specific force of infection was estimated to occur in 5- to 9-year-olds. The early age at infection corresponded with a low estimated incidence of congenital rubella syndrome (CRS) of 0.3 per 1000 live births, equivalent to nine cases of CRS in 1994. The predicted critical level of immunity for elimination of rubella via vaccination was 85-91%, requiring 89-96% coverage with a vaccine of 95% effectiveness. Unless very high coverage of rubella vaccine could be guaranteed, the introduction of childhood vaccination could increase the incidence of CRS in Addis Ababa.

HIV-1 subtype C in commerical sex workers in Addis Ababa, Ethiopia

In this study, we have investigated the diversity of the current HIV-1 strains circulating in Addis Ababa, Ethiopia; in addition, we have evaluated the applicability of peptide enzyme-linked immunosorbent assay (ELISA) and heteroduplex mobility assay (HMA) for HIV-1 subtyping. Previous studies have indicated that HIV-1 subtype C is the major subtype present in HIV-positive samples collected from various risk groups between 1988 and 1995 in Addis Ababa. To assess the possible influx of new HIV-1 subtypes, 150 commercial sex workers (CSW) reporting in 1997 to two Health Centers in Addis Ababa were enrolled in an unlinked anonymous cross-sectional study. Subtyping was performed according to the World Health Organization algorithm of peptide ELISA, followed by HMA and DNA sequencing. As a result, the HIV-1 prevalence among these CSWs was found to be 45% (67 of 150). Of the 67 samples, 66 contained HIV-1 of subtype C and only one was of subtype D. This confirms the persistent overall presence of HIV-1 subtype C in Addis Ababa and a low influx of other subtypes into this location.

HIV-1 subtype C syncytium- and non-syncytium-inducing phenotypes and coreceptor usage among Ethiopian patients with AIDS

OBJECTIVE

To assess syncytium-inducing (SI) and non-syncytium-inducing (NSI) frequencies, coreceptor usage and gp120 V3 sequences of HIV-1 isolates from Ethiopian AIDS patients.

PATIENTS

Cross-sectional study on 48 hospitalized AIDS patients (CD4 T cells < 200 x 10(6) cell/l) with stage III or IV of the WHO staging system for HIV-1 infection and disease.

METHODS

Peripheral blood mononuclear cells (PBMC) from all 48 patients were tested by MT-2 assay to determine SI/NSI phenotypes. Lymphocyte subsets were enumerated using Coulter counting and FACScan analysis. Viral load determination used a nucleic acid sequence-based amplification assay (NASBA). Coreceptor usage of HIV-1 biological clones was measured using U87 CD4/chemokine receptor transfectants and phytohemagglutinin-stimulated PBMC of healthy donors with wild-type CCR5 and homozygous mutation CCR5delta32 (a 32 base-pair deletion in CCR5). Reverse transcriptase polymerase chain reaction sequencing was performed on the third variable region (V3) of the HIV-1 gene gp120. Sequence alignments were done manually; phylogenetic analyses used PHYLIP software packages.

RESULTS

SI viruses were detected for 3/48 (6%) AIDS patients only. Lower mean absolute CD4 counts were determined in patients with SI virus compared with NSI (P = 0.04), but no differences in viral load were observed. All patients were found to be infected with HIV-1 subtype C, based on V3 sequencing. NSI biological clones used CCR5 as coreceptor; SI biological clones used CXCR4 and/or CCR5 and/or CCR3.

CONCLUSIONS

Ethiopian patients with HIV-1 C-subtype AIDS harbour a remarkably low frequency of SI phenotype viruses. Coreceptor usage of these viruses correlates with their biological phenotypes.

A comparison of oral fluid and serum for the detection of rubella-specific antibodies in a community study in Addis Ababa, Ethiopia

OBJECTIVE

To assess the utility of oral fluid compared with serum for the determination of age-prevalence of rubella-specific antibodies in an urban African community setting.

METHOD

Paired serum and oral fluid samples were collected from 439 individuals aged 0-49 years in Addis Ababa, Ethiopia, as part of a larger seroepidemiological survey in 1994. Oral fluid was sampled using a simple sponge device that was well accepted by subjects of all ages; venous blood was collected by Vacutainer system. We measured rubella-specific antibodies in serum by the Radial Haemolysis (RH) test, supported by two confirmatory assays, and in oral fluid by IgG antibody-capture radioimmunoassay (GACRIA).

RESULTS

Sensitivity and specificity of oral fluid results compared to serum were 89% and 76%, respectively. Sensitivity declined from 96% in age group 0-19 years to 90% in age group 20-29 and 78% in age group 30-49. Specificity was 86% in 0-9 year olds contrasting with 61% in older groups (10-49 years). The positive predictive value of an oral fluid sample was high in all age groups (range 92-100%), while the negative predictive value declined from > or =80% in those aged <10 years to <10% in those aged > or =30 years. Serum confirmatory tests suggested a proportion of false serum RH negatives, increasing with age, indicating a need to standardize serum as well as oral fluid tests.

CONCLUSION

In the community setting of a developing country, oral fluid surveys could be useful to estimate age-prevalence of rubella immunity and identify rubella-susceptible children for follow-up. Further work is required to simplify assays and sample processing, improve assay sensitivity and estimate assay specificity more precisely, and compare and standardise collection methods suitable for surveillance of a variety of childhood viral infections.

Age- and sex-specific HIV-1 prevalence in the urban community setting of Addis Ababa, Ethiopia

OBJECTIVE

To estimate the age and sex-specific prevalence of HIV infection in the population of Addis Ababa, Ethiopia.

DESIGN

Two-stage cluster sampling of the population aged 0-49 years of Addis Ababa, using kebeles (urban dwelling associations) as clusters.

METHODS

The sera used for this study were collected in an earlier study (1994) on the rate of acquisition of antibodies against measles, rubella, and hepatitis B. After separate approvals were obtained from the institutional ethics committees, sera were tested by enzyme-linked immunosorbent assay confirmed by Western blot. Age- and sex-specific HIV prevalence rates were estimated. The prevalence of HIV in men and women over 15 years of age was compared by calculating age-standardized HIV prevalence, using the age distribution of the census population as the standard. A time-dependent catalytic model was used to obtain crude estimates of HIV incidence from age-prevalence data.

RESULTS

A total of 3853 sera were available for analysis. The prevalence of HIV in adults was 6.0% [95% confidence interval (CI), 4.5-7.4%] for men and 6.9% (95% CI, 5.3-8.5%) for women, with peak prevalence in the 25-29 year age group of 16.3 and 11.8%, respectively. After standardization for age using the direct method, the HIV prevalence ratio comparing adult men with women was 0.97:1 (95% CI, 0.70:1 - 1.35:1). Three children aged less than 5 years were HIV-positive. The prevalence of HIV among adults ranged from 0-21.3% in different clusters, indicating the heterogeneity of the spread of HIV in the city. HIV prevalence estimates among the antenatal clinic patients of Addis Ababa in 1996 far exceeded the estimates obtained during the community survey, particularly in the youngest age group (15-24 years). Estimates of HIV incidence (per susceptible person per annum) for the age group 16-22 years ranged from 1.3-2.25% for men and from 2.1-2.4% for women.

CONCLUSION

By 1994, a substantial proportion of the adult population of Addis Ababa was infected with HIV. Promotion of behavioural changes and the control of sexually transmitted diseases should be strongly supported to limit the spread of the HIV epidemic in Ethiopia.