Larvicidal, Ovicidal, and Repellent Activities of Leucas stachydiformis (Hochst. ex Benth.) Briq Essential Oil against Anopheles arabiensis.

Larvicidal, ovicidal, and repellent activities of the essential oil extracted by hydrodistillation from the leaves of the endemic Ethiopian plant Leucas stachydiformis (Hochst. ex Benth.) Briq were investigated against Anopheles arabiensis, the dominant malaria vector species in Ethiopia with the objective of searching for a plant-based malaria vector control strategy from medicinal plants. The larvicidal effect was tested against the fourth instar An. arabiensis wild larvae whilst freshly laid ova of An. arabiensis were used to determine the ovicidal activity of the essential oil at concentrations ranging from 6.25 to 400 ppm. Concentrations of 41.6-366.7 µg/cm2 were used to evaluate the repellent activity of the essential oil on 3-5 days old adult female An. arabiensis. The oil composition of L. stachydiformis was also analyzed using GC-MS. The study revealed that the oil possesses the highest larvicidal activity at 400 ppm and 200 ppm after 24 h and 48 h of treatment. LC50 values for the fourth larval instar after 24 h and 48 h of treatment were 43.4 ppm and 34.2 ppm, respectively. After 72 h of exposure, the oil displayed 100% ovicidal activity at 400 ppm with an IH50 value of 32.2 ppm. In the repellency test, at concentrations of 366.7, 133.3, and 41.6 µg/cm2, the oil gave a total percentage protection of 67.9 ± 4.2%, 37.2 ± 2.8%, and 32 ± 2.2%, respectively, for 4 h. The highest concentration (366.7 µg/cm2) gave 100% protection up to 90 min. GC-MS analysis of the oil revealed the presence of 24 compounds representing 90.34% of the total oil with caryophyllene oxide, germacrene D, and trans-caryophyllene constituting more than 50% of its components. Results of the present study suggest that the essential oil of L. stachydiformis has the potential to be used for the control of An. arabiensis mosquitoes.

In vitro and in vivo antitrypanosomal activity of the fresh leaves of Ranunculus Multifidus Forsk and its major compound anemonin against Trypanosoma congolense field isolate.

BACKGROUND: Animal trypanosomiasis is a major livestock problem due to its socioeconomic impacts in tropical countries. Currently used trypanocides are toxic, expensive, and the parasites have developed resistance to the existing drugs, which calls for an urgent need of new effective and safe chemotherapeutic agents from alternative sources such as medicinal plants. In Ethiopian traditional medicine fresh leaves of Ranunculus multifidus Forsk, are used for the treatment of animal trypanosomiasis. The present study aimed to evaluate the antitrypanosomal activity of the fresh leaves of R. multifidus and its major compound anemonin against Trypanosoma congolense field isolate. METHODS: Fresh leaves of R. multifidus were extracted by maceration with 80% methanol and hydro-distillation to obtain the corresponding extracts. Anemonin was isolated from the hydro-distilled extract by preparative TLC. For the in vitro assay, 0.1, 0.4, 2 and 4 mg/ml of the test substances were incubated with parasites and cessation or drop in motility of the parasites was monitored for a total duration of 1 h. In the in vivo assay, the test substances were administered intraperitoneally daily for 7 days to mice infected with Trypanosoma congolense. Diminazene aceturate and 1% dimethylsulfoxide (DMSO) were used as positive and negative controls, respectively. RESULTS: Both extracts showed antitrypanosomal activity although the hydro-distilled extract demonstrated superior activity compared to the hydroalcoholic extract. At a concentration of 4 mg/ml, the hydro-distilled extract drastically reduced motility of trypanosomes within 20 min. Similarly, anemonin at the same concentration completely immobilized trypanosomes within 5 min of incubation, while diminazene aceturate (28.00 mg/kg/day) immobilized the parasites within 10 min. In the in vivo antitrypanosomal assay, anemonin eliminates parasites at all the tested doses (8.75, 17.00 and 35.00 mg/kg/day) and prevented relapse, while in diminazene aceturate-treated mice the parasites reappeared on days 12 to 14. CONCLUSIONS: The current study demonstrated that the fresh leaves of R. multifidus possess genuine antitrypanosomal activity supporting the use of the plant for the treatment of animal trypanosomiasis in traditional medicine. Furthermore, anemonin appears to be responsible for the activity suggesting its potential as a scaffold for the development of safe and cost effective antitrypanosomal agent.

The potential of Ethiopian medicinal plants to treat emergent viral diseases.

Ethiopians have deep-rooted traditions of using plants to treat ailments affecting humans and domesticated animals. Approximately 80% of the population continues to rely on traditional medicine, including for the prevention and treatment of viral diseases. Many antiviral plants are available to and widely used by communities in areas where access to conventional healthcare systems is limited. In some cases, pharmacological studies also confirm the potent antiviral properties of Ethiopian plants. Building on traditional knowledge of medicinal plants and testing their antiviral properties may help to expand options to address the global pandemic of COVID-19 including its recently isolated virulent variants and prepare for similar outbreaks in the future. Here, we provide an ethnobotanical and pharmacological inventory of Ethiopian medicinal plants that might contribute to the prevention and treatment of viral diseases. We identified 387 species, about 6% of Ethiopia's known flora, for which records of use by local communities and traditional herbalists have been documented for the treatment of viral diseases. We provide a framework for further investigation and development of this vital resource much anticipated to help combat emergent viral diseases along with existing ones in Ethiopia and elsewhere.

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.

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.

Prevalence, Perception and Predictors of Concomitant Herbal Medicine Use among HIV/AIDS and Tuberculosis Patients in Metekel Zone, Northwest Ethiopia: A Cross-Sectional Study.

Background: The use of herbal medicine is common in Ethiopia. However, evidence on the extent and predictors of concomitant use of herbal medicine with conventional treatment among HIV/AIDS and tuberculosis patients is limited. Objective: To assess the extent of concomitant use of herbal medicine with conventional therapy and associated factors among HIV/AIDS and tuberculosis patients in Metekel Zone, Northwest Ethiopia. Method: A cross-sectional study was conducted from January to March 2020. HIV/AIDS and tuberculosis patients who visited the health facilities during the study were interviewed face-to-face using a structured and pretested questionnaire. The descriptive statistics and univariate and multivariate logistic regression analyses were conducted using SPSS version 25. A P-value of <0.05 was considered significant. Results: 412 patients on conventional treatment were included in this study; 355 (86.2%) were HIV patients, and 57 (13.8%) were TB patients. More than half, 217 (52.7%) participants reported using herbal medicine while on conventional therapy. Among those who claimed to have used herbal medicines, 32 (14.7%) received herbal medicine from traditional healers. About four of five herbal users did not disclose their use to their healthcare providers. The type of health facility on follow-up (P=0.03), disease status (P=0.01), occupation (P=0.02), discontinuing ART (P=0.03), and encountering side (P=0.04) were the determinant factors for the use of herbal medicine among our study participants. Conclusion: In the Metekel Zone, concomitant consumption of herbal medication is common among HIV/AIDS and tuberculosis patients. Furthermore, most patients did not disclose the healthcare practitioners about their herbal use. Therefore, healthcare practitioners must assess and counsel patients regarding the potential adverse effects and herb-drug interaction to optimize therapy.

Teratogenic Evaluation of 80% Ethanol Extract of Embelia schimperi Vatke Fruits on Rat Embryo and Fetuses.

Introduction: Embelia schimperi Vatke (family Myrsinaceae) is a commonly consumed anthelminthic plant in Ethiopia. The plant has significant efficacy in treating intestinal worms. However, there are limited data about the safety/toxicity of the plant. Moreover, the teratogenic effect of the plant is not yet well studied despite significant number of Ethiopian mothers consuming herbal medication during their pregnancy. Purpose: This study aimed to evaluate the teratogenic effect of the hydroalcoholic extract of E. schimperi fruit on rat embryos and fetuses. Methods: Pregnant albino Wistar rats were treated with 80% hydroalcoholic fruit extract of E. schimperi at 250 mg/kg, 500 mg/kg, and 1000 mg/kg dosage, whilst the controls were pair-fed and ad libitum groups. Maternal food intake, maternal weight gain, number of implantations, number of prior resorptions, fetal viability, fetal weight, fetal and embryonic crown-ramp length, placental weight, placental gross morphology and histopathology of placental tissue, number of somites, embryonic system, gross/visceral morphological malformations, and ossification centers were evaluated as teratogenicity indices. Results: The crude extract of E. schimperi did not exhibit a significant difference in most developmental indices including the development of a circulatory system, nervous system, and musculoskeletal systems among treated animals and the controls. However, histopathological evaluation of placentas from the treatment groups showed that inflammatory reactions and calcifications compared to the pair-fed and ad libitum controls. Conclusion: Administration of the 80% hydroalcoholic extract of E. schimperi fruit during the period of organogenesis in rats did not show a significant toxic effect on embryonic and fetal developmental indices. However, it might affect the structural integrity of the placenta as it is evidenced by inflammatory reactions and calcifications of decidua basalis of rat placenta.

Prenatal Developmental Toxicity and Histopathological Changes of the Placenta Induced by Syzygium guineense Leaf Extract in Rats.

Many of the traditional herbal products are served to the consumer without proper efficacy and safety investigations. A laboratory-based experimental study was employed to investigate the toxic effects of Syzygium guineense leaf extract on the fetal development and histopathology of the placenta in rats. Fifty pregnant Wistar albino rats were randomly allocated into five groups, each consisting of 10 rats. S. guineense leaf extract, at doses of 250, 500, and 1000 mg/kg of body weight, was respectively administered to groups I-III rats. Groups four and five were control and ad libitum control, respectively. The number of resorptions, implantation sites, and live or dead fetuses was counted. The weight and crown-rump length of the fetuses were measured. The histopathological investigation of the placenta was conducted. Administration of 70% ethanol extract of S. guineense leaves reduced weight gain and food intake of pregnant rats at p value <0.05. The crown-rump length of the near-term rat fetus was significantly reduced in rats treated with 1000 mg/kg body weight of S. guineense extract (p value <0.05). The plant extract did not affect the number of implantations, fetal resorptions, live births, and stillbirths. The weight of the fetuses and the placentae also decreased dose-dependently. Decidual cystic degeneration was the most prevalent histopathological change observed in a rat's placenta treated with 1000 mg/kg body weight of S. guineense extract. Consumption of S. guineense leaves, especially at a high dose, may affect fetal development. Therefore, liberal use of S. guineense leaves during pregnancy should be avoided.

In Vivo Antimalarial Activity of the Leaf Extract of Osyris quadripartita Salzm. ex Decne and Its Major Compound (-) Catechin.

Background: The leaves of Osyris quadripartita Salzm. ex Decne, endemic to Ethiopia, are traditionally used for the treatment of malaria. Previous phytochemical investigations of Osyris species showed the presence of flavonoids, anthracene derivatives, and sesquiterpene lactones as the main constituents. The aim of the present study was to investigate the antimalarial activity of the leaf extract of O. quadripartita and its isolated constituent against mice infected with Plasmodium berghei. Methods: Isolation of a compound was carried out on silica gel column chromatography of the extract eluting with gradient mixtures of CHCl3/MeOH. Structural elucidation of the isolated compound was achieved by ESI-MS and 1D-and 2D-NMR spectral data. Peter's 4-day suppressive test method was used to determine the antimalarial activity of the test substances. Level of parasitemia, survival time, and body weight change were used to determine the antimalarial activity of the test substances. Results: (-) Catechin was isolated and characterized from the hydroalcoholic extract of O. quadripartita. At a concentration of 400 mg/kg, both the extract and (-) catechin exhibited antimalarial activity with the highest chemosuppression values of 70.61% and 64.26%, respectively. Conclusion: These findings indicate that O. quadripartita is endowed with genuine antimalarial activity attributed in part, to its (-) catechin content. Hence, the present study may validate the traditional use of the plant for the treatment of malaria.

Anti-malarial effect of a combination of risedronate and azithromycin against Plasmodium yoelii nigeriensis infection in Swiss mice.

Combination therapy is used to retard the selection of malaria parasite strains resistant to individual components of a combination of drugs. This approach has proved to be a success in the combination of sulphadoxine and pyrimethamine, which targets two different steps in the folate pathway of malaria parasites. However, after the success of this therapeutic combination, the efficacy of other combinations of drugs that target different enzymes in a particular metabolic pathway has, apparently, not been reported. In the current study, the antimalarial effect of a combination of risedronate (RIS), which is known for its anti-osteoporosis activity, and azithromycin (AZT) was investigated. Peter's suppression test was carried out on mice infected with 1 × 107P. yoelii infected erythrocytes. Drug efficacy was analyzed by comparing the percent reduction in parasitaemia on day 4 post-infection. RIS was observed to be a blood schizonticidal agent against P. yoelii infection which showed ED50 7.0 (4.04-12.13) mg/kg/day x 4. Normalized isobologram showed additive action between RIS 1 mg/kg/day x 4 and AZT 10 mg/kg/day x 4, and antagonistic action for the rest of the combinations (RIS 1 + AZT 20, RIS 1 + AZT 40, RIS 5 + AZT 10, RIS 5 + AZT 20, RIS 5 + AZT 40, RIS 10 + AZT 10, RIS 10 + AZT 20 and RIS 10 + AZT 40 mg/kg/day x 4). Furthermore, a combination of RIS with AZT showed inferior efficacy as compared to AZT treatment alone. This antagonistic interaction may be due to the high accumulation of AZT in WBCs, which will reduce its serum bio-availability, whereas RIS has anti-parasitic activity by increasing WBCs.

The Developmental Toxicity of Thymus schimperi Essential Oil in Rat Embryos and Fetuses.

Background: In Ethiopian traditional medicine, the aerial parts of Thymus schimperi are widely used to treat diseases such as gonorrhea, cough, liver disease, kidney disease, hypertension, stomach pain, and fungal skin infections. In addition, they have been used as vegetables to flavor a broad variety of food products. However, there is an insufficient investigation of the toxic effect of Thymus schimperi essential oil. The aim of this study was, therefore, to evaluate the developmental toxicity of the essential oil of Thymus schimperi leaves on developing rat embryos and fetuses. Methods: Essential oil of the aerial parts of Thymus schimperi was extracted by hydrodistillation. Pregnant Wistar albino rats were randomly divided into five groups. The doses 65 mg/kg, 130 mg/kg, and 260 mg/kg of the essential of Thymus schimperi were administered by force feeding to the III-V groups, respectively. Groups I and II were negative and ad libitum control groups. The embryos and fetuses were revealed on days 12 and 20 of gestations, respectively. The embryos were examined for developmental delays or growth retardation. Gross external, skeletal, and visceral anomalies in the fetuses were examined. Results: In this study, the developmental scores of the number of implantation sites, crown-rump length, the number of somites, and morphological scores were significantly lower while the score of fetal resorptions was increased in a 12-day-old rat embryos treated with 260 mg/kg of the Thymus schimperi essential oil. There was also a significant delay in the development of the otic system, olfactory system, and a reduction in the number of branchial bars in 12-day-old embryos treated with 130 mg/kg and 260 mg/kg of the essential oil. However, external morphological examinations of rat fetuses revealed no detectable structural abnormalities. The fetal skull, vertebrae, hyoid, forelimb, and hindlimb ossification centers did not differ significantly across all the groups. Furthermore, there were no skeletal or soft-tissue malformations as a result of the essential oil treatment. Although the difference was not statistically significant, fetuses of the high-dose treatment group had a reduced number of ossification centers in the caudal vertebrae and hind limp phalanges. Conclusion: The essential oil of Thymus schimperi at high doses has a detrimental effect on the development of rat embryos and fetuses. Its developmental toxicity is evidenced by significant delays in fetal and embryonic development, a decrease in the number of implantation sites, and an increase in fetal resorption. Furthermore, administration of the essential oil in higher doses resulted in a significant decrease in placenta weight and litter weight. In addition, the present study provided evidence that using the Thymus schimperi essential oil in a high dose could affect the developing embryo and fetus. Thus, it is recommended to discourage the use of Thymus schimperi essential oil in high doses.

In Vitro Antileishmanial and Antitrypanosomal Activities of Plicataloside Isolated from the Leaf Latex of Aloe rugosifolia Gilbert & Sebsebe (Asphodelaceae).

Trypanosomiasis and leishmaniasis are among the major neglected diseases that affect poor people, mainly in developing countries. In Ethiopia, the latex of Aloe rugosifolia Gilbert & Sebsebe is traditionally used for the treatment of protozoal diseases, among others. In this study, the in vitro antitrypanosomal activity of the leaf latex of A. rugosifolia was evaluated against Trypanosoma congolense field isolate using in vitro motility and in vivo infectivity tests. The latex was also tested against the promastigotes of Leishmania aethiopica and L. donovani clinical isolates using alamar blue assay. Preparative thin-layer chromatography of the latex afforded a naphthalene derivative identified as plicataloside (2,8-O,O-di-(ß-D-glucopyranosyl)-1,2,8-trihydroxy-3-methyl-naphthalene) by means of spectroscopic techniques (HRESI-MS, 1H, 13C-NMR). Results of the study demonstrated that at 4.0 mg/mL concentration plicataloside arrested mobility of trypanosomes within 30 min of incubation period. Furthermore, plicataloside completely eliminated subsequent infectivity in mice for 30 days at concentrations of 4.0 and 2.0 mg/mL. Plicataloside also displayed antileishmanial activity against the promastigotes of L. aethopica and L. donovani with IC50 values 14.22 ± 0.41 µg/mL (27.66 ± 0.80 µM) and 18.86 ± 0.03 µg/mL (36.69 ± 0.06 µM), respectively. Thus, plicataloside may be used as a scaffold for the development of novel drugs effective against trypanosomiasis and leishmaniasis.

In Vitro Antileishmanial and Antischistosomal Activities of Anemonin Isolated from the Fresh Leaves of Ranunculus multifidus Forsk.

Leishmaniasis and schistosomiasis are neglected tropical diseases (NTDs) infecting the world's poorest populations. Effectiveness of the current antileishmanial and antischistosomal therapies are significantly declining, which calls for an urgent need of new effective and safe drugs. In Ethiopia fresh leaves of Ranunculus multifidus Forsk. are traditionally used for the treatment of various ailments including leishmaniasis and eradication of intestinal worms. In the current study, anemonin isolated from the fresh leaves of R. multifidus was assessed for its in vitro antileishmanial and antischistosomal activities. Anemonin was isolated from the hydro-distilled extract of the leaves of R. multifidus. Antileishmanial activity was assessed on clinical isolates of the promastigote and amastigote forms of Leishmania aethiopica and L. donovani clinical isolates. Resazurin reduction assay was used to determine antipromastigote activity, while macrophages were employed for antiamastigote and cytotoxicity assays. Antischistosomal assays were performed against adult Schistosoma mansoni and newly transformed schistosomules (NTS). Anemonin displayed significant antileishmanial activity with IC50 values of 1.33 nM and 1.58 nM against promastigotes and 1.24 nM and 1.91 nM against amastigotes of L. aethiopica and L. donovani, respectively. It also showed moderate activity against adult S. mansoni and NTS (49% activity against adult S. mansoni at 10 µM and 41% activity against NTS at 1 µM). The results obtained in this investigation indicate that anemonin has the potential to be used as a template for designing novel antileishmanial and antischistosomal pharmacophores.

In Vivo Antimalarial Activity of Leaf Extracts and a Major Compound Isolated from Ranunculus multifidus Forsk.

The leaves of Ranunculus multifidus Forsk. are traditionally used for the treatment of malaria in several African countries. In the present study, 80% methanol (RM-M) and hydrodistilled (RM-H) extracts of fresh leaves from R. multifidus and its major constituent anemonin were tested for their in vivo antimalarial activity against Plasmodium berghei in mice. Anemonin was also tested for its in vitro antimycobacterial activity against Mycobacterium smegmatis and M. abscessus in a microbroth dilution assay, and bacterial growth was analyzed by OD measurement. The isolation of anemonin from RM-H was carried out using preparative thin layer chromatography (PTLC). The chemical structures of anemonin and its hydrolysis product were elucidated using spectroscopic methods (HR-MS; 1D and 2D-NMR). Results of the study revealed that both RM-M and RM-H were active against P. berghei in mice, although the latter demonstrated superior activity (p < 0.001), as compared to the former. At a dose of 35.00 mg/kg/day, RM-H demonstrated a chemosuppression value of 70% in a 4-day suppressive test. In a 4-day suppressive, Rane's and prophylactic antimalarial tests, anemonin showed median effective doses (ED50s) of 2.17, 2.78 and 2.70 µM, respectively. However, anemonin did not inhibit the growth of M. smegmatis and M. abscessus.

Toxic Effect of Khat in Rat Embryos and Fetuses.

Khat (Catha edulis Forsk) is a plant consumed by many people in Eastern Africa, including Ethiopia, and Southern Arabia to be stimulated. There are several human and animal studies on khat that provide information about its toxic effects. However, the potential toxic effects of khat on embryos and fetuses have not been elucidated. The aim of the present study was to investigate the embryotoxic and fetotoxic effects of khat exposure during the earliest period of gestation in rats. Pregnant Wistar albino rats were treated with khat extract at 250, 500, and 750 mg/kg doses from day 6 through day 12 of gestation. The treatment was delivered by gavage. Embryos and fetuses were recovered on gestational day 12 or day 20, respectively, and were quantitatively and qualitatively assessed for developmental anomalies. Placentae from the treatment and control groups were investigated for histopathological effects. Results of the present study showed that khat exposure during pregnancy had dose-dependent toxic effects in rat embryos and fetuses. Prenatal growth retardation such as reduced fetal weight and crown-rump length was observed in near-term fetuses, especially, in animals treated with the highest dose of khat (p < 0.05). Growth retardation and developmental anomalies were also observed in day 12 embryos of khat-treated rats. Maternal weight gain of the khat-treated group was also significantly lower than the control group. Cytolysis, decidual hypoplasia, and atrophy were observed in the placenta of the khat-treated rats. Findings of the present study revealed, for the first time, that exposure of pregnant rat to crude extract of khat causes embryotoxic and fetotoxic effects.

Composition of the Essential Oil Thymus schimperi and Evaluation of Its Acute and Subacute Toxicity in Wistar Albino Rats: In Silico Toxicity Studies.

BACKGROUND: In Ethiopian traditional medicine, the aerial part of Thymus schimperi is widely used to treat diseases such as gonorrhea, cough, liver disease, kidney disease, hypertension, stomach pain, and fungal skin infections. However, there is insufficient investigation on the toxic effect of the essential oil of T. schimperi. The aim of this study was, therefore, to evaluate the acute, subacute, and in silico toxicity of Thymus schimperi essential oil in the Wistar albino rats. METHOD: Essential oil of the aerial part of T. schimperi extracted by hydrodistillation was analyzed by GC-MS. The oil was subjected to toxicity studies. In the acute toxicity study, rats were randomly divided into seven groups (n = 5). The control group received only distilled water with 2% of tween 80, whereas the experimental groups received single doses of 300, 600, 900, 1200, 1500, and 2 000 mg/kg of the oil. In the subacute toxicity study, rats were randomly divided into four groups (n = 10). The control group received distilled water with 2% of tween 80, whereas the experimental groups received 65 mg/kg, 130 mg/kg, and 260 mg/kg of the oil orally for 28 days. At the end of the experiment, blood samples were collected for hematology and clinical chemistry evaluation. Gross pathology and histopathology of the liver and the kidneys were also evaluated. For the in silico toxicity study, PubChem CID numbers of GC-MS identified bioactive compounds in the essential oil of T. schimperi obtained from PubChem. Chemdraw (8.0) was used to construct two-dimensional structures of the compounds. The Swiss ADMET web tool was used to convert the two-dimensional structures into a simplified molecular-input line input system (SMILES). In addition, the toxicity parameters were predicted via vNN and ADMET servers. RESULTS: In this study, the LD50 of the essential oil of T. schimperi was found to be 1284.2 mg/kg. According to the World Health Organization, the oil is classified as moderately hazardous in its oral administration. In the subacute toxicity study, rats showed no significant changes in behavioral indices, gross pathology, body weight, biochemical, and most hematological parameters. However, hematological profiles showed a significant decrement in WBC counts and a significant increment of MCV in high dose (260 mg/kg) groups as compared to the control group. Furthermore, no significant differences were observed between the control and essential oil-treated groups, observed in the gross histopathology of the liver and the kidneys. In the in silico toxicity study, all compounds derived from the essential oil showed no cardiac toxicity (h-ERG Blocker), AMES (Ames Mutagenicity), and cytotoxicity via ADMET and vNN-ADMET toxicity predictors. However, by using these servers, about 8.6% of the compounds showed hepatotoxicity, only 3.45% caused drug-induced liver injury, and only 1.75% were potentially toxic to the mitochondrial membrane. CONCLUSION: From the results of this study, oral administration of the essential oil T. schimperi up to a dose of 130 mg/kg is not harmful. However, in the high-dose (260 mg/kg) group, the WBC count was significantly decreased and the MCV was significantly increased. In the in silico toxicity study, most of the components of the oil were found to be nontoxic, although a few of the compounds showed hepatotoxicity and mitochondrial membrane potential toxicity. It is, therefore, essential to conduct chronic toxicity of the essential oil as well as its components, which showed toxicity in the in silico study before using preparations containing the essential oil of T. schimperi.

Ethiopian Medicinal Plants Traditionally Used for the Treatment of Cancer; Part 3: Selective Cytotoxic Activity of 22 Plants against Human Cancer Cell Lines.

Medicinal plants have been traditionally used to treat cancer in Ethiopia. However, very few studies have reported the in vitro anticancer activities of medicinal plants that are collected from different agro-ecological zones of Ethiopia. Hence, the main aim of this study was to screen the cytotoxic activities of 80% methanol extracts of 22 plants against human peripheral blood mononuclear cells (PBMCs), as well as human breast (MCF-7), lung (A427), bladder (RT-4), and cervical (SiSo) cancer cell lines. Active extracts were further screened against human large cell lung carcinoma (LCLC-103H), pancreatic cancer (DAN-G), ovarian cancer (A2780), and squamous cell carcinoma of the esophagus (KYSE-70) by using the crystal violet cell proliferation assay, while the vitality of the acute myeloid leukemia (HL-60) and histiocytic lymphoma (U-937) cell lines was monitored in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) microtiter assay. Euphorbia schimperiana, Acokanthera schimperi, Kniphofia foliosa, and Kalanchoe petitiana exhibited potent antiproliferative activity against A427, RT-4, MCF-7, and SiSo cell lines, with IC50 values ranging from 1.85 ± 0.44 to 17.8 ± 2.31 µg/mL. Furthermore, these four extracts also showed potent antiproliferative activities against LCLC-103H, DAN-G, A2780, KYSE-70, HL-60, and U-937 cell lines, with IC50 values ranging from 0.086 to 27.06 ± 10.8 µg/mL. Hence, further studies focusing on bio-assay-guided isolation and structural elucidation of active cytotoxic compounds from these plants are warranted.

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

Teratogenic Effect of High Dose of Syzygium guineense (Myrtaceae) Leaves on Wistar Albino Rat Embryos and Fetuses.

Syzygium guineense is an important medicinal plant effective against hypertension, diabetes mellitus, and cancer but with no evidence of its teratogenicity. This study was planned to investigate the teratogenic potential of S. guineense leaves on rat embryos and fetuses. Five groups of Wistar albino rats, each consisting of ten pregnant rats, were used as experimental animals. Groups I-III rats were treated with 250, 500, and 1000 mg/kg of hydroethanolic extract of S. guineense leaves, and groups IV and V were control and ad libitum control, respectively. Rats were treated during day 6-12 of gestation. Embryos and fetuses were retrieved at day 12 and day 20 of gestation, respectively. The embryos were assessed for developmental delays and growth retardation. The fetuses were examined for gross external, skeletal, and visceral anomalies. In 12-day old rat embryos, crown-rump length, number of somites, and morphological scores were significantly reduced by the treatment of 1000 mg/kg of the extract. The external morphological and visceral examinations of rat fetuses did not reveal any detectable structural malformations in the cranial, nasal, oral cavities, and visceral organs. The ossification centers of fetal skull, vertebrae, hyoid, forelimb, and hindlimb bones were not significantly varied across all groups. However, even if not statistically significant, high-dose treated rat fetuses had a reduced number of ossification centers in the sternum, caudal vertebrae, metatarsal, metacarpal, and phalanges. Treatment with the hydroethanolic extract of S. guineense leaves produced no significant skeletal and soft tissue malformations. The plant extract did not produce significant teratogenic effects on rat embryos/fetuses up to 500 mg/kg doses but retarded the growth of embryos at high dose (1000 mg/kg) as evidenced by decreased crown-rump length, number of somites, and morphological scores. Therefore, it is not advisable to take large doses of the plant during pregnancy.

In vivo anti-malarial activity of the hydroalcoholic extract of rhizomes of Kniphofia foliosa and its constituents.

BACKGROUND: Kniphofia foliosa is a flamboyant robust perennial herb which has dense clumps and tick upright rhizomes with leaves at the base. In Ethiopia, it has several vernacular names including Abelbila, Ashenda, Amelmela, Yeznjero Ageda, Shemetmetie and Yezinjero Ageda. The plant is endemic to Ethiopian highlands, where its rhizomes are traditionally used for the treatment of malaria, abdominal cramps and wound healing. In the present study, the 80% methanol extract of K. foliosa rhizomes and its constituents are tested against Plasmodium berghei in mice. METHODS: Isolation was carried out using column and preparative thin layer chromatography (PTLC). The chemical structures of the compounds were elucidated by spectroscopic methods (ESI-MS, 1D and 2D-NMR). Peters' 4-day suppressive test against P. berghei in mice was utilized for in vivo anti-malarial evaluation of the test substances. RESULTS: Two compounds, namely knipholone and dianellin were isolated from the 80% methanolic extract of K. foliosa rhizomes, and characterized. The hydroalcoholic extract (400 mg/kg) and knipholone (200 mg/kg) showed the highest activity with chemosuppression values of 61.52 and 60.16%, respectively. From the dose-response plot, the median effective (ED50) doses of knipholone and dianellin were determined to be 81.25 and 92.31 mg/kg, respectively. Molecular docking study revealed that knipholone had a strong binding affinity to Plasmodium falciparum l-lactate dehydrogenase (pfLDH) target. CONCLUSION: Results of the current study support the traditional use of the plant for the treatment of malaria.