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

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

Repellent activity of essential oil of the stem of Kleinia squarrosa against mosquitoes

Most commercially available repellents of mosquitoes and other biting arthropods are synthetic and  have a severe toxic effect to human. Moreover, these chemicals cause an irreversible damage to the ecosystem as some of them are non-degradable in nature. Therefore, there is a need to develop safe and effective alternatives to the currently available chemicals used to control vectors. In southern Ethiopia, the smoke obtained from burning the stem of Kleinia squarrosa Cufod. is used as a fumigant to ward off mosquitoes. In the present study hydrodistillation of the powdered stem of K. squarrosa gave a pale yellow oil (0.04%; w/w) with a characteristic pungent odor. A total of twenty-seven compounds have been identified by GC-MS analysis, accounting 48.71% of the total oil. The main constituents of the oil were (E)-iso-γ-bisabolene (9%), α-pinene (5.74%), caryophyllene (5.36%) and sabinene (5.55%). The powdered stem of K. squarrosa was also burned, and the smoke extracted to yield a trace amount brownish oil. Analysis of the oil by GC-MS afforded 36 compounds comprising 94.56% of the total peak area. Terpene-4-ol (18.09%), (E)-iso-γ-bisabolene (14.07%), 5-epi-7-epi-α-eudesmol (12.45%), and caryophyllene (8.35%) figured as major compounds. Mosquito repellent activity of the essential oil was tested on guinea pigs against Anopheles gambiae by a modified Kunming mice technique under laboratory testing conditions. The essential oil exhibited a dose-dependent repellent action in the dose range tested (0.03 - 5%; v/v) with ED50 and ED99.9 values of 1.49% and 4.74% (v/v), respectively. The study further revealed that that the essential oil possesses a 3 h complete protection time. The similarity in the chemical profiles of the essential oil and the oil extracted from the smoke obtained by burning K. squarrosa stem supports the traditional use of the plant as a fumigant to kill mosquitoes.Keywords: Kleinia squarrosa; fumigant; essential oil; mosquito repellent; Anopheles gambia

Antibacterial activity of extracts from Myrtus communis L. (Ades) and Dodoneae angustifolia L.F. (Kitkita) using bioautography method

The increasing prevalence of antibacterial drug resistant organisms in our globe and high prevalence of infectious diseases in developing countries has led to new efforts in the search of bioactive compounds from complex chemical composition of plant extracts. A bioautographic agar overlay assay using Staphylococcus aureous as the indicator organism for the detection of antimicrobial compounds from ten extracts of Myrtus communis L. and Dodoneae angustifolia L was analyzed. Hexane, dichloromethane, acetone, methanol and water solvents are used as extractant and ethyl acetate: methanol: water, chloroform: ethyl acetate: acetic acid and benzene: ethanol: ammonia solvent systems were used to separate the components from all the extract of Myrtus communis L. and Dodoneae angustifolia L. Our results indicated that the extracts of Myrtus communis L.f. and Dodoneae angustifolia L had bioactive constituents responsible for their antibacterial potentials. Water solvents extracted small number of antibacterial compounds from both plants, followed by hexane extractant; while dichloromethane, acetone and methanol extractant shared similarities in bioactive compounds on bioautograms, and extracted the highest number of antibacterial compounds with variety of polarities. Chloroform: ethyl acetate: acetic acid solvent system separated the largest number of biologically active components in all extractants. As a high number of antibacterially active compounds were found in M. communis and D. angustifolia extracts of dichloromethane, acetone and methanol, we recommend assay guided fractionation, isolation and dosage formulation of these antibacterial compounds from these plants for clinical applications. Keywords/phrases: Antibacterial, Bioactive-compound, Bioautography, Dodonaea angustifolia, Myrtus communisEthiop. J. Biol. Sci., 10(1): 57-72, 201

Antihyperglycemic, Vasodilator, and Diuretic Activities of Microencapsulated Bioactive Product from Moringa stenopetala Leaves Extract

Moringa stenopetala has nutritional and medicinal values, which is widely used by the local communities. The study aimed to evaluate the antihyperglycemic, vasodilator, and diuretic activities of the microencapsulated bioactive product from M. stenopetala leaves extract. Microencapsulation of the extract was done by spray drying technique using maltodextrin and pectin as coating materials with the core: coating ratio of 1 : 6. Then, the antihyperglycemic, diuretic, and vasodilator activities were evaluated after the product was administered to experimental animals at different doses and compared with the control groups. There were no observed physical, behavioral, and physiological changes on the mice during the acute toxicity test. The results also indicated no toxicity signs and death occurrence in the experimental animals up to 5000 mg/kg administered dose. Therefore, microencapsulated M. stenopetala leaves extract does not produce adverse effects in experimental mice. The study also showed that the microencapsulated bioactive product exhibited significant antihyperglycemic, vasodilator, and diuretic activities as the doses increase. Therefore, the study showed that microencapsulated bioactive product has significant medicinal values. Further detailed studies are recommended on chronic toxicity tests and to understand the possible mechanism of actions on the antihyperglycemic, vasodilator, and diuretic activities of the microencapsulated product