Physicochemical characterization of biochars from Eucalyptus maiden Entandrophragma cylindricum (Liboyo), Milicia excelsa (Muvula.) and Ocotea michelsonie (licheche) used in Goma city, DR Congo for water treatment potentials

In recent years, research on biochar as an eco-friendly material and cost-effective means for water treatment, soil amendment and carbon sequestration has gained more attention due to the availability of feedstock, the simplicity of the preparation methods, and their enhanced physico-chemical properties. Given that pyrolysis temperature and resident time amongst other factors have significant effect on biochar’s pollutant removal efficacy, this study focused on the evaluation of some properties of biochars produced by pyrolysis (500 - 600 °C) from Entandrophragma cylindricum (ECB), Eucalyptus maiden (EMB), Milicia excelsa (MEB) and Ocotea michelsonie (OMB) sawdusts for their water treatment potentials by using standardized methods. Biomass generated from wood mill in the city of Goma (DR Congo) is valorised for the first time as potential water purifier. The highest yield was obtained from OMB (36.6%) which was found to be significantly greater that those of ECB and EMB (p<0.05). All the biochars had neutral to weakly alkaline pH (7.10-7.90), very high porosity (92-94%, with EMB having the highest value) and ash content between 9.40 and 18.40%, with the highest value attributed to OMB). Most physical and chemical characteristics of biochars varied significantly due to different wood species. Potential toxic elements were far belowenvironmental threshold values and exchangeable cations were equally detected in the biochars. The obtained biochars are therefore seen as good media for water treatment.

Prospects of botanical pesticides in management of Iroko gall bug, Phytolyma fusca (Hemiptera, Psylloidea) under laboratory and field conditions

Background Iroko gall bug, Phytolyma fusca Walker, is a major insect pest of Milicia excelsa (Iroko) seedling hampering its propagation in West Africa. Milicia excelsa is an indigenous forest timber tree in the tropical rain forest of West Africa with a very high value in international trade due to its wood quality. Sustainable management of P. fusca infestations on Iroko seedlings have not been achieved due to their cryptic nature and multivoltine generations. This study evaluated the residual and contact effects of crude ethanol and aqueous extracts of four plants (Azadirachta indica, Jatropha curcas, Piper guineense, and Aframomum melegueta) on adult P. fusca in the laboratory and field. Results All the extracts had residual effects and contact effects on adult insects in the laboratory at 75% and 100% concentrations of applications. Azadirachta indica, P. guineense, and A. melegueta gave 80–100% adult mortality at both concentrations in the laboratory; their efficacies were comparable to cypermethrin. The ethanol extracts of P. guineense and A. indica were more effective than other extracts in protecting the seedlings against Phytolyma infestations in the field. They significantly (p < 0.01) reduced infestation compared to other extracts and control. Ethanol extracts of the tested plant materials were more effective than their aqueous extracts both in the laboratory and field. Conclusion The results proved that P. guineense and A. indica extracts were very potent and promising in protecting Milicia excelsa seedlings against Phytolyma fusca infestations and they can be used in the early management of Phytolyma infestations in the field.

In vitro antiplasmodial, cytotoxic and antioxidant effects, and phytochemical constituents of eleven plants used in the traditional treatment of malaria in Akwa Ibom State, Nigeria

Purpose: To evaluate the antiplasmodial effects of eleven plants (Bombax buonopozense, Carica papaya, Anthocleista djalonensis, Milicia excelsa, Heterotis rotundifolia, Homalim letestui, Starchystarpheta cayennnensis, Ocimum gratissimum, Cleistopholis patens, Chromolaena odorata and Hippocratea africana) reportedly used in the treatment of malaria in Akwa Ibom State of Nigeria. Methods: Phytochemical analysis was done by standard methods, while in vitro antiplasmodial evaluation was carried out using Plasmodium falciparum chloroquine-sensitive and chloroquineresistant strains using lactate dehydrogenase (pLDH) assay. Cytotoxicity test was undertaken by MTT assay on LLC-MK2 cells and the concentration killing 50 % of the cells (CC50) was calculated.Antioxidant activity of the ethanol extract was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Results: Milicia excelsa, Heterotis rotundifolia and Chromolaena odorata had moderate antiplasmodial activity. Ocimum gratissimum and Hippocratea africana were weakly active. Milicia excelsa showed a considerable level of cytotoxicity, while Bombax buonopozense exhibited moderate cytotoxicity. Bombax buonopozense (95.3 %) and Ocimum gratissimum (92.0 %) exhibited high DPPH scavengingeffect comparable to Vitamin C (98.7 %). There was a significant correlation (p < 0.05) between DPPH inhibition and the total phenolic contents of the eleven plants studied (r2 = 0.6616), between DPPH inhibition and flavonoids (r2 = 0.3553), between antiplasmodial activity and saponin content (r2= 0.3992), and between the two antiplasmodial evaluation assay methods (r2 = 0.614).Conclusion: The results of this work provide some justification for the use of Milicia excelsa, Heterotis rotundifolia, Chromolaena odorata, Ocimum gratissimum and Hippocratea africana in the treatment of malaria. Keywords: Antiplasmodial, Antioxidant, Cytotoxicity, Phytochemicals, Antimalaria

EFFECTS OF NEEM OIL ON THE PRESERVATION OF MILICIA EXCELSA: EVALUATION OF TERMITICIDAL EFFECTIVENESS

Wood usage has increased with time, thus, there is need to investigate how wood can be treated with human and environmentally friendly preservative which is effective in protecting wood from termites and other agents of wood deterioration, or improve the wood physical, chemical, mechanical and biological characteristics. The aim of this study was therefore to evaluate the effects of neem oil on Milicia excelsa wood preservation. Treated and untreated pieces of Milicia excelsa wood samples were used to carry out this experiment, a soil bed, and an internal wood exposure to termite’s test was carried out, and measurements taken using a digital weighing machine. The results obtained showed that, when Milicia excelsa is treated with neem oil, its Rate of Decay (ROD) reduces as compared to the untreated pieces. Also, neem oil treated wood when exposed to termite’s attack experiences a slower weight loss compared to untreated samples with significant weight loss. Neem oil is thus not only effective in preserving woods, but also non- toxic to human and the environment.

Population structure, harvesting rate and regeneration status of four woody species in Kimboza forest reserve, Morogoro region - Tanzania

Kimboza forest reserve is recognized as an IUCN category IV-habitat and species management area, but the information on population structure, harvesting rate and regeneration status of four commercial woody species, namely; Khaya anthotheca, Milicia excelsa, Pterocarpus angolensis and Dalbergia melanoxylon in the forest are lacking. This study, therefore, aims to fill this gap. A total of five transects were established in the forest whereby within each transect, five nested quadrats of 20 m × 20 m were placed at 200 m distance for sampling stems with diameter at breast height (DBH) ≥ 10 cm and stumps of the target species. Stems with DBH <10 cm were counted in a quadrat of 5 m × 5 m placed within the big quadrat. The findings show that density of stems & harvesting rate for Khaya anthotheca, Milicia excelsa, Pterocarpus angolensis and Dalbergia melanoxylon were 4.8 stems ha-1 & 6.6 stumps ha-1, 12.6 stems ha-1 & 3.4 stumps ha-1, 16.0 stems ha-1 & 2.8 stumps ha-1, and 5.6 stems ha-1 & 1.2 stumps ha-1, respectively. The DBH class distribution for Khaya anthotheca, Milicia excelsa and Pterocarpus angolensis displayed a good regeneration pattern, however, the last two were interrupted in high size classes. The Dalbergia melanoxylon revealed a poor regeneration pattern. The study recommends that illegal harvest of the species should be controlled, environmental education be provided to locals, and stringent measures be institutionalized against illegal loggers.

Effect of Potassium Carbonate Catalyst on Pyrolysis of Milicia excelsa in a Fixed Bed Reactor

The effect of potassium carbonate catalyst on the products distribution from pyrolysis of Milicia excelsa (Iroko) at various temperatures (400, 500 and 600 oC) was investigated. Milicia excelsa sawdust was obtained from a sawmill in Ogbomoso, South-Western Nigeria and was sundried for five days in order to reduce its moisture content. Catalytic pyrolysis of the sawdust was performed with different amounts of catalyst (10, 20, 30 and 40 wt.%). Non-catalytic pyrolysis was also performed for the same temperatures and the products distributions from both batches were compared. Char yield generally increased with increase in catalyst amount for all the temperatures considered. Tar yield did not follow any definite pattern with increasing amount of catalyst as different trends were obtained for different temperatures. Gas yield generally decreased with increase in catalyst amount in the feed. Char yields from non-catalytic experiments were higher than those obtained from catalytic runs, with the highest value of 68% at 400 oC. Tar yields from catalytic pyrolysis were higher than those from non-catalytic process at 400 oC (biomass/catalyst ratio of 90/10) and at 500 oC (biomass/catalyst ratios of 70/70 and 60/40), the highest yield being 29.47% at 500 oC and biomass/catalyst ratio of 60/40. Gas yields from catalytic pyrolysis were higher than those from non-catalytic runs except at 500 oC (biomass/catalyst ratio of 60/40), the highest being 51.3% at 600 oC (biomass/catalyst ratio of 90/10). By making use of appropriate biomass/catalyst ratio and temperature, the yield of liquid fuel from catalytic pyrolysis of Milicia excelsa can be increased.Keywords— Catalyst, potassium carbonate, pyrolysis, biomass, product distribution

Phytochemical Screening and Antioxidant Potential of Aqueous Extracts of Millettia laurenti, Lophira alata and Milicia excelsa, Commonly Used in the Cameroonian Pharmacopoeia

Aims: As the world nowadays is turning towards the research of biologically active natural compounds, this work aimed at assessing the antioxidant potential of compounds contained in the aqueous extracts of three common Cameroonian pharmacopoeia plants, namely Millettia laurenti (Wengé) seeds, Lophira alata (Azobé) leaves and Milicia excelsa (Iroko) barks and the associated bioactive compounds. Methodology: After being dried and ground, they were macerated in water and the polyphenols, tannins, flavonoids, and alkaloids quantified. The antioxidant potential of the extracts was evaluated through DPPH free radical scavenging, NO scavenging, phosphomolybdate method (TAC), and iron-reducing power (FRAP). Results: The mean concentrations obtained ranged between 527 and 1213 µg GAE/g DM for polyphenols, 0.39 and 0.65 µg GAE/g DM for tannins, 19.79 and 27.06 µg QE/g DM for flavonoids, 15.72 and 16.02 µg QuE/g DM for alkaloids. Aqueous extracts of Wengé (AE-WG) and Azobé (AE-AZ) exhibited the highest and significantly similar contents. AE-AZ presented the highest iron reducing power (0.015 µg AAE/g DM at 10 mg/mL) and NO scavenging (IC50=3.63 mg/mL) while AE-WG showed the highest DPPH scavenging activity (IC50 = 4.20 mg/mL) and total antioxidant capacity (0.39 µg AAE/g DM at 10 mg/mL). No significant correlation was observed between studied bioactive compounds and the different antioxidant responses except flavonoids and tannins with TAC (p<0.05). Conclusion: AE-AZ and AE-WG exhibited different antioxidant mechanisms and are therefore of high interest for potential use in the food industry and medicine with reserves to toxicological studies.

In-vitro Seed Germination Biology of Milicia Excelsa Population Collected from Benchi-Maji Zone, South Western Ethiopia

Background: In Ethiopia, species used for timber production are limited to few species. So, it is becoming necessary to find innovative ways of maintaining and improving the genetic quality of species such as Milicia excelsa by domesticating them into a wider scale of ecological and social environment. Hence, the main objective of this study was to investigate the seed germination biology and behavior of Milicia excelsa under in-vitro laboratory conditions so as to promote the domestication and establishment of seed production areas (SPA) in-situ. Methods: Seeds collected from Benchi district of Benchi-Maji zone of southwestern Ethiopia were subjected to germination biology in-vitro to determine the germination responses of M. excelsa seeds under laboratory conditions. So, a total of 1200 seeds were randomly selected, treated and prepared using four treatments procedures with six replications for paper method and 3 replications for sand method, and tested using paper methods in CRD design. So, 600 seeds were tested using paper and sand methods each where 25 seeds were tested for each replication in paper and 50 seeds for each replication in sand method. The germination process was lasted between 19 March 2020 and 15 May 2020. Result: The mean germination percentage of seeds of M. excelsa was noticed to be lower than 20%. This is below the expected (45%) germination rate of mature and healthy seed lot. Overall, seeds that were not treated using any pre-sowing treatments has shown relatively better germination percentage (19%) followed by seeds rubbed by hand (15%). Analysis of one-way t-test shows that the effects untreated (control –T1) and rubbing by hand treatments (T4) is significant at p < 0.05 compared to the effects of the other pre-sowing treatments (T2- seeds only washed with normal tap water, and T3- seeds washed and soaked in hot water for 15 minutes) on the germination capability of seeds of M. excelsa . However, no significance difference was observed between control (T1) and hand scarification (T2). Conclusions: The average germination of M. excelsa seeds combined for all treatments is lower than 20% which is lower germination when comparing with other similar research reported in other countries. Therefore, it required to include and test other pre-sowing treatments including tissue culture micro-propagation of seeds to maximize the germination of M. excelsa seeds helping to get enough seedlings required for the domestication project.

Population survey of Milicia excelsa, Pouteria adolfi-fridercii, Antiaris toxicaria and Prunus africana in south and south-western Ethiopia: implications for domesticating and establishing Seed Production Areas

The population dynamics and genetic qualities of stem height and dbh of the populations of Milicia excelsa, Pouteria adolfi-fridercii, Antiaris toxicaria and Prunus africana were assessed and studied in 14 forest ecosystems in south and south-western Ethiopia. A systematic random quadrat sampling technique was employed to identify potential habitat area for selected timber species in south and south-western Ethiopia. So, a total of 10 parallel transect lines were set out across each forest habitat. Milicia excelsa was assessed in four forest ecosystems; Bebeka -Duduka natural forest (45 tree stem ha-1) and Yayu coffee mixed forest (40 tree stem ha-1) appeared to have relatively denser population of M. excelsa compared to the other pilot forests. Similarly, statistically larger stem height (m) is observed in Bebeka-Duduka natural forest (x̅=29.5, SD=4.2) and larger dbh size (cm) in Bebeka 1 coffee mixed forest (x̅=48.5, SD=25.2) at p<0.05. Hence, Bebeka-Duduka natural forest and Bebeka 1 coffee mixed forests are identified for in-situ SPA establishment project of the target species. Pouteria adolfi-fridercii was assessed in eight forest ecosystems; Masha-Gora shewi forest appeared to have dense population of P. adolfi-fridercii (150 tree stem ha-1) followed by Bebeka-Kebereta (80 tree stem ha-1) as compared to the remaining pilot forests. However, statistically larger stem height (m) is scored in Bebeka 2 natural forest (x̅=30.6, SD=2.98) and Bebeka-kebereta forest (x̅=30.0, SD=4.4) and larger dbh size (cm) in Bebeka 2 natural forest (x̅=96.5, SD=19.9) at p<0.05. So, Bebeka 2 natural forest and Bebeka-kebereta forest are identified for SPA establishment project of the target species. Antiaris toxicaria was assessed in two forest ecosystems where both forest habitats appeared to have the same density of Antiaris toxicaria in hectare. Moreover, analyses of mean stem height (cm) of Bebeka 1 forest (x̅=21.4, SD=5.2) and Bebeka-kebereta forest (x̅=22.4, SD=2.7), and mean dbh size (cm) of Bebeka 1 forest (x̅=48, SD=16.4) and Bebeka-kebereta forest (x̅=48, SD=8.2) appeared to have not significantly different at p<0.05. Prunus africana was assessed in five forest ecosystems; Masha-Gora shewi forest appeared to have dense population of Prunus africana (150 tree stem ha-1) followed by Kaho-shemeta forest (130 tree stem ha-1) as compared to the remaining pilot forests. However, statistically larger stem height (m) is scored in Kaho-shemeta natural forest (x̅=31, SD=7.6) and larger dbh (cm) in Masha-Gora shewi forest (x̅=64.7, SD=28.2) at p<0.05. As the result, Kaho-shemeta natural forest and Bonga-Teja-adela forest are identified for establishment of seed production area of the target species in-situ. Hence, while implementing the project of domestication and seed production area establishment in south and south-western Ethiopia, in-situ and ex-situ areas must be selected and delineated in accordance with this preliminary information of the population dynamics and genetic qualities of stem height and diameter at breast height. The survey data generated in this study would bridge the research gap in relation to the population status of the target tree species in the designated area.