Allelopathic Potential of Lantana camara L. Leaf Extracts and Soils Invaded by It on the Growth Performance of Lepidium sativum L.

Lantana camara is a noxious invasive plant that invades agricultural and natural ecosystems. In the current study, phytotoxicity of hexane and ethanolic leaf extracts of L. camara in different concentrations and soils invaded by it on Lepidium sativum were investigated under laboratory conditions. Soil toxicity was evaluated by comparing the growth of L. sativum on soils sampled from Lantana-invaded and Lantana-free sites. Results showed that extract concentrations and solvent type and their interaction significantly reduced percent seed germination and seedling growth. Compared to control (distilled water), both hexane and ethanol extracts at 5% w/v concentration significantly reduced percent germination and early seedling growth and completely inhibited seed germination at 10% w/v of hexane leaf extract, suggesting that hexane extract has a greater inhibitory effect than ethanolic extract in all the parameters measured. However, growth performance and seed yield of L. sativum grown on soil invaded by Lantana did not significantly vary from those grown on soils sampled from noninvaded sites. The results of this study generally showed that though Lantana leaf extracts have a direct negative allelopathic effect on L. sativum, soils invaded by Lantana have no toxic materials in the soil to directly or indirectly inhibit the growth of L. sativum. Further field studies on allelopathic effects of Lantana on L. sativum are recommended.

Population Structure and Regeneration Status of Woody Plant Species in Tulu Korma Dry Afromontane Forest, West Shewa Zone, Oromia, Ethiopia.

A study was conducted on Tulu Korma afromontane forest to assess woody plant species' population structure and natural regeneration status. Data were collected from 52 main quadrats of 400 m2 for mature woody species and 260 subplots of 25 m2 for seedlings and saplings. All live woody plant species were recorded with their densities, heights, and DBH. Frequency, basal area, importance value, and Shannon-Wiener diversity indices were computed. A total of 101 species that belonged to 45 families were documented. Diversity and evenness indices were 3.44 and 0.7, respectively. Combined density of woody species of all developmental stages was 4971 stems ha-1 of which 39, 32, and 28% were with DBH < 3.5 cm (seedlings), between 2 and 10 cm (saplings), and >10 cm (mature wordy species), respectively. The total basal area of individuals with DBH ≥ 3.5 cm was 116.18 m2 ha-1. Olea europaea and Podocarpus falcatus were the most dominant species. About 41.58% of the species had IVI < 1. Population structure based on combined densities revealed that density of seedling > sapling > mature individuals, suggesting healthy population structure and good regeneration. On individual basis, however, species showed different patterns of population structure of which 12, 51, and 37% species showed good, fair, and poor regenerations, respectively. Species with least IVI and poor regeneration should be given conservation priority.

An ethnomedicinal study in tulo district, west hararghe zone, oromia region, Ethiopia.

Traditional medicinal plants used by local Oromo people of Tulo District in west Hararghe, Ethiopia, were investigated before people's medicinal knowledge vanishes. Data on medicinal plants and demography were obtained between November 2019 and October 2020 through semi-structured interviews, group discussion and direct guided onsite observation to elicit information from 376 non-traditional and 20 traditional medicine practitioners. Ethnobotanical indices including informant consensus factor (ICF), preference ranking (PR), fidelity level (FL), relative frequency of citation (RFG) and cultural importance (CI) were employed for the data analysis. Moreover; descriptive statistics, t-test, analysis of variance and linear regression were used to reveal the effects of socio-demographic factors on respondents' traditional medicinal knowledge. Totally 104 plants distributed among 98 genera and 55 families were enumerated for the treatment of 60 illnesses. Seventy-seven of these medicinal plants serve to treat human ailments, whereas 11 and 16 of them were used for livestock and for both, respectively. Asteraceae and Lamiaceae were species rich families. Leaves were the most frequently (41.53%) reported structures for the preparation of remedies. Crushing was the principal approach (34.50%) of remedy preparation. Oral administration was frequently (66.08%) used route of application. The highest ICF was observed for swelling and hemorrhoid (0.90) category. Metabolic and degenerative as well as other ailment categories had the least ICF values. About 66% of medicinal plants had FL value of 100%. In PR, G. abyssinica was ranked first to treat cough. RFC values varied from 0.03 to 0.18 with the highest record for Salvia nilotica (0.18) followed by Lepidium sativum, Rydingia integrifolia and Nigella sativa each with 0.16; Euphorbia abyssinica and Asplenium monanthes each with 0.15. Extensive use of land for agricultural purpose was key threat to medicinal plant of Tulo District. All the tested socio-demographic features except religion significantly (P < 0.05) affected the traditional knowledge on medicinal plants possessed by the study population. The results of this study reveals that the people of Tulo District rely on traditional medicine of plant origin, and their indigenous knowledge is instrumental to exploit the most potential plants for further validation. Therefore, the medicinal plant species wealth of the study site and the associated indigenous knowledge need to be preserved.

Effect of Extraction Solvents on Total Polyphenolic Content and Antioxidant Capacity of Syzygium Aromaticum L. Flower Bud from Ethiopia.

In this study, the antioxidative activity and polyphenolic content of Syzygium aromaticum's flower bud were compared under different extraction solvents including chloroform, ethyl acetate, methanol, and aqueous. The antioxidant activity was assessed via established in vitro assay models such as 2, 2-diphenyl-1-Picrylhydrazyl (DPPH) radical scavenging assay, NO- radical scavenging assay, H2O2 scavenging assay and Fe3+ reducing capacity. Total phenolic content was measured according to Folin-Ciocalteu's method, and total flavonoid content was estimated by using the aluminum chloride colorimetric method. The results showed that aqueous extract possessed the highest TPC (19.11 ± 2.76 mg GAE/g DW) and TFC (15.32 ± 1.53 mg CtE/g DW). Among the extracts, methanol extract exerted the strongest radical DPPH quenching activity with an IC50 value of 303.56 ± 13.14 µg/mL. The highest NO- radical scavenging activity was shown by methanol extract (IC50192.94 ± 1.9 µg/mL) which is stronger than BHT (IC50247.64 ± 12.89 µg/mL). Methanol extract showed a strong H2O2 scavenging activity (IC50233.71 ± 3.72 µg/mL). The highest Fe3+ reducing capacity was shown by methanol extract (Absorbance = 0.36 ± 0.05). Strong and positive correlations were observed between total phenolic and flavonoid contents and the antioxidant assays. The results of the present work revealed that the tested spice demonstrated high antioxidant activity, total phenolics, and flavonoids. Thus, this spice is worth considering as important source of natural antioxidant agents.

In vitro antioxidant activity and polyphenolic content of commonly used spices from Ethiopia.

INTRODUCTION: In this study, the antioxidative effectiveness, and polyphenolic content of methanol and aqueous extracts of spices such as Lippia adoensis (Koseret), Nigella sativa (Thikur azmud), Piper capense (Timiz), Thymus schimperi (Tosign) and Trachyspermum ammi (Netchazmud), consumed among people of Ethiopia were investigated. METHODS: The antioxidant activity was assessed via established in vitro assay models such as 2, 2-Diphenyl-1-Picrylhydrazyl (DPPH) radical quenching assay, reducing power assay and reactive nitrogen species (RNS) inhibitory potential. Total phenolics content was measured according to Folin-Ciocalteu's method and total flavonoid content was estimated by using Aluminium chloride colorimetric method. RESULTS: The results showed that the total phenolic content was highest in both methanol (720 ± 0.04 mg GAE/100 g extract DW) and aqueous (580 ± 0.08 mg GAE/100 g DW) extracts of L. adoensis. Among the five tested spices, the methanol and aqueous extracts of L. adoensis exerted the strongest DPPH radical quenching activity with IC50values of 49.17 ± 1.26 and 20.99 ± 8.6 µg/mL, respectively. Both methanol and aqueous extracts of L. adoensis showed notable reducing capacity. The highest RNS scavenging activity was shown by both methanol (IC50 597.21 ± 6.99 µg/mL) and aqueous (IC50 = 551.5 ± 28.9 µg/mL) extracts of L. adoensis. High to moderate positive correlations were observed between total phenolic contents and in vitro antioxidant assays. This indicates that the antioxidant activities of the tested spices are attributed to the phenolic contents. CONCLUSION: The results of the present work revealed that the tested spices demonstrated high phenolic contents and antioxidant properties. Thus, these spices are worth considering as important sources of natural antioxidant agents.

Field evaluation of a botanical formulation from the milky mangrove Excoecaria agallocha L. against Helicoverpa armigera Hübner. in Abelmoschus esculentus (lady's finger) and Cajanus cajan (pigeon pea).

OBJECTIVE: To evaluate a formulation from the milky mangrove tree Excoecaria agallocha L. (E. agallocha) against Helicoverpa armigera Hubner (H. armigera). METHODS: About 3% aqueous ethanolic spray formulation derived from the lipophilic extract of E. agallocha (dry leaf) was evaluated against H. armigera in Abelmoschus esculentus (lady's finger) and Cajanus cajan (C. cajan) (pigeon pea), under field conditions. RESULTS: On the 9th day of the 4th spray the larval count in the plot treated with 3% E. agallocha formulation drastically came down to 0.23 larva/plant, compared to 1.63 in the ethanol control plot and 1.60 in the unsprayed plot. Blocks sprayed with 3% E. agallocha formulation yielded 35.8 quintals/hectare (q/ha) of healthy pods compared to Ekalux® (pod yield: 60.7 q/ha), 3% Vijay Neem® (60.22 q/ha), yield plot (6 q/ha) and ethanol control (7 q/ha). In C. cajan, 1% E. agallocha, 3% Nimbecidine® and 0.07% indoxacarb were equally potent in reducing the larval population of H. armigera and the non-target pest Spilosoma obliqua to 0%, from the 9th day (3rd spray). Indoxacarb plot recorded the maximum yield of 16.1 q/ha with 2.4% pod damage. Plots sprayed with 1% E. agallocha yielded 14.7 q/ha with 2.32% pod damage. The effect of 3% Nimbecidine® spray (14.35 q/ha) was comparable to E. agallocha formulation. Unsprayed and ethanol control plots yielded 12.41 and 11.2 q/ha of pods with an average pod damage of 4.7%. CONCLUSIONS: E. agallocha formulation was found to be promising for the control of H. armigera, under field conditions.