Antimicrobial Efficacy of Vitellaria paradoxa fractions and compounds on some wood Fungi and Bacteria

This study examined antifungal efficacy of Vitellaria paradoxa fractions and compounds in the control of some wood degrading fungi. Stem bark and heartwood parts of Vitellaria paradoxa were collected, dried, pulverised and macerated sequentially in n- hexane, methanol and ethyl acetate solvents. The mixtures were filtered, evaporated and the dried samples were mixed and run over silica gel in column chromatography with a mixture of n -hexane and ethyl acetate solvents to obtain fractions. The fractions collected were evaporated and those with white needles were subjected to Magnetic Resonance (NMR) spectroscopic analysis. Spinasterol was isolated and characterised from the heartwood fraction while the stem bark fractions were fatty. Vitellaria paradoxa fractions were active against Serpula lacrymans, Sclerotium rolfsii, Aspergillus fumigatus, Fomitopsis pinicoca, Phaeolus schweinitzii, Rhizopus sp., Coniophora puteana, Gloeophyllum sepiarium, and Fibroporia vaillantii at zones of inhibition (ZOI) of 18 mm - 24 mm. Although the antibiotics were active (25 – 31 mm), they were found inactive against the Fomitopsis pinicoca fungus which was sensitive to all the V. paradoxa fractions at zones of inhibition of 18 - 24 mm. The minimum inhibitory concentrations (MIC) of the V. paradoxa fractions were active at 50 μg/mL against all test fungi. At minimum fungicidal concentration (MFC) of between 50 - 200 μg/mL, all the test fungi were killed. Based on the ZOI, MIC and MFC, the V. paradoxa stem bark heartwood fractions have been proven to be very efficient in inhibiting the growth of test wood rot fungi; hence the species could be explored as a potential source of bioactive fungicides

Antibacterial activities of sawdust and stem bark of Sasswood tree (Erythrophleum suaveolens, Guill. & Perr. Brenan, 1917) extracts against selected wood bacteria

This study assessed the antibacterial properties of sawdust and stem bark of Erythrophleum suaveolens extracts on selected wood bacteria. Erythrophleum suaveolens samples were collected, dried and macerated by dissolving 1 Kg and 0.60 Kg of stem bark and sawdust respectively into 1 L of n-hexane, ethyl acetate and methanol. Sporfloxacin ciprofloxacin and cefuroxine antibiotics were used as control. The mixture was left for 24 hours then filtered and the filtrates evaporated to dryness. Qualitative phytochemical screening, zone of inhibition, minimum inhibitory and Bactericidal Concentrations (MIC/MBC) were determined according to standard methods. Tannins, steroids, saponins, glycosides, flavonoids, carbohydrates anthraquinones and alkaloids phytochemicals were present in E. suaveolens extracts. Zone of inhibition (32 – 37 mm) of antibiotics on test bacteria compared favourably with 17 – 24 mm of E. suaveolens extracts. Erythrophleum suaveolens ethyl acetate and methanol E. suaveolens extracts inhibited Staphylolococus aureus, Ralstonia solanacearum, Proteus mirabilis, Enterococcus faecium and Acidobacterium capsulatum growth at MIC of 10 mg/mL and n-hexane extracts at 20 mg/mL. At MBC of 20 mg/mL methanol stem bark extract completely killed most test bacteria. Methanol extracts were the most active extracts. The study has shown that E. suaveolens extracts can be explored in the control of plant diseases caused by test bacteria in the study. Key words: Antibacterial, E. suaveolens, extract, phytochemicals, zone of inhibitio

Antibacterial Activity of Triterpenes from the Stem Bark and Heartwood of Erythrophleum suaveolens (Guill. & Perr.) Brenan

The antibacterial activity of compounds isolated from the stem bark and sawdust of Erythrophleum suaveolens were evaluated. Extraction of the pulverized plants materials was carried out using hexane, ethyl acetate and methanol. Extracts were fractionated using column chromatography and fractions were examined using Nuclear Magnetic Resonance spectroscopy. Antibacterial activities against Acidobacterium capsulatum, Actinobacterium sp., Agrobacterium tumefaciens, Bacillus subtili, Ralstonia solanacearum, Enterococcus faecium, Escherichia coli, Pseudomonas syringae, Pseudomonas aeruginosa and Proteus mirabilis were also carried out. A novel triterpene, 21-acetoxylupenone and betulin were identified in the fractions from the stem bark of E. suaveolens while cycloeucalenol and stigmasterol were obtained from the sawdust extract fractions. Pseudomonas aeruginosa was resistant to all control antibiotics but was inhibited by 21- acetoxylupenone and cycloeucalenol with 23 mm and 24 mm diameter of Zones of Inhibition. Acidobacterium capsulatum, Actinobacterium sp., Agrobacterium tumefaciens, Ralstonia solanacearum, and Proteus mirabilis were completely inhibited at Minimum Bactericidal Concentration (MBC) of 50 µg/mL, while Bacillus subtilis, Enterococcus faecium, Escherichia coli, Pseudomonas syringae, and Pseudomonas aeruginosa were completely inhibited at MBC values of 100 µg/mL. Thus E. suaveolens stem bark and saw dust isolates can be used in the control of plants diseases where these pathogens are the causative agents.Keywords: Antibacterial, Triterpenes, 21-acetoxylupenone, Cycloeucalenol, Betulin, Nigeri

Antifungal Activity of Compounds obtained from Sawdust and Stem Bark of Sasswood Tree (Erythrophleum suaveolens) on Wood Rot Fungi

Extracts and compounds from the sawdust and stem bark of Erythrophleum suaveolens were studied for antifungal activity. The plant materials were extracted using hexane, ethyl acetate and methanol to obtain the crude extracts. Column chromatography over silica gel was used to purify the extracts and obtain pure compounds. Betulin and 21- acetoxylupenone were obtained from the stem bark and cycloeucalenol from the sawdust. The compounds were very active on most of the fungi with zones of inhibition between 18 to 23 mm. Minimum Inhibition Concentration (MIC) was highest at 50 µg/mL against Aspergillus fumigatus, Coniophora puteana, Fibroporia vaillantii, Fomitopsis pinicoca, Gloeophyllum sepiarium, Phaeolus schweinitzii and Rhizopus spp. whereas antifungal activity was least at MFC of 200 µg/mL. The study demonstrated that E. suaveolens stem bark and sawdust isolates possess antifungal activity and could be used in the control of the soft-rot, brown-rot, wet rot and white-rot of wood and diseases caused by wood fungi.Keyword: Antifungal, Betulin, Erythrophleum suaveolens, 21-acetoxylupenone

Phytochemical screening and antifungal activity of sawdust and stem bark extracts from Erythrophleum suaveolens (Guill. & Perr) Brena

This study was carried out to investigate the antifungal potentials of stem bark and sawdust of Erythrophleum suaveolens. Stem bark was collected from Federal University of Agriculture (FUAM) while sawdust sample was collected from Timber Shed Makurdi. Both samples were air dried while the stem bark was ground into powder for extraction. Extraction of samples was done sequentially by macerating 1000 g and 600 g of stem bark and sawdust, respectively using 1000 mL (w/v) of n-hexane for 24 hours and filtering off the hexane extract followed by ethyl acetate and methanol in that order for 24 hours each. Extracts were filtered and evaporated to obtain dried extracts and yields calculated. Phytochemical screening of samples was carried out according to AOAC standard methods. Diffusion method was used for antifungal screening of extracts. Sabouraud Dextrose agar was prepared as media in Petri dishes where Zones of Inhibition were observed for fungal growth. Minimum Inhibitory Concentration (MIC) of extracts was determined according to broth dilution technique at 40 g/mL, 20 g/mL, 10 g/mL, 5 g/mL and 2.5 g/mL. Minimum Fungicidal Concentration (MFC) determined by sub culturing MIC to determine the least concentration at which fungi were killed. Percentage yield of extract was highest (5.19 %) in stem bark and lowest (0.12 %) in sawdust. Methanol extracts had the highest yield (5.19 % and 3.42 %) for stem bark and sawdust followed by ethyl acetate (1.06 % and 0.36 %) and n’ hexane (0.16 % and 0.12 %), respectively. Flavonoids, glycosides, saponins, steroids, and tannins were in the stem bark while, anthraquinones, saponins and tannins were completely absent in the E. suaveolens sawdust. Zones of Inhibition (ZOIs) of antibiotics ranged between 27 mm – 35 mm while ZOIs for crude extracts ranged from 18 mm – 28 mm. At MIC of 5 mg/mL, E. Suaveolens stem bark methanol extract inhibited Coniophora puteana and Fomitopsis pinicoca growth. At MFC of 10 mg/mL the same microbes were killed. Erythrophleum suaveolens stem bark methanol can be used in the control of brown-rot decay and stem decay caused by Coniophora puteana and Fomitopsis pinicoca.Keywords: Antifungal, brown-rot decay, stem decay, Erythrophleum suaveolens, Coniophora puteana, Fomitopsis pinicoca, Antimicrobial, Aspergillus fumigatu

Evaluation of the aflatoxin contamination and proximate composition of groundnut (Arachis hypogea L.) infected by Aspergillus spp.

Aflatoxins B1 concentration and the proximate composition of groundnuts consumed in six Local Government Areas (LGAs) of Benue State in the Southern Guinea Savannah agro- ecological zone of Nigeria were evaluated. Seed health testing was conducted and associated fungi were identified. Aflatoxin B1 (AfB1) produced by Aspergillus flavus were detected and the concentrations quantified using the Enzyme Linked Immunosorbent Assay (ELISA) method. Proximate content of seeds was determined using standard methods of Official Analytical Chemists. Aspergillus flavus Link and Aspergillus niger van Tiegh were the associated fungi found in contaminated groundnut seeds with 15.67 % and 7.67 % occurrence respectively. A combination of both fungi had 4.67 % occurrence. The proximate content of groundnut seed samples ranged from 0.35 % to 40.21 % across the samples analyzed. The proximate analysis indicated that groundnut samples from Agatu LGA had significantly (P  0.05) higher protein and fat content of 29.11 % and 40.21 % respectively compared with samples from other LGAs samples. Groundnut samples from Makurdi LGA had significantly (P  0.05) higher ash content while samples from Ohimini recorded significantly (P  0.05) higher crude fibre. The highest moisture content (9.37 %) was from groundnut seeds from Otukpo LGA. The contamination of the groundnut samples by AfB1 resulted in a significant (P  0.05) reduction in the nutritional quality of the groundnut seeds.Keywords: Aflatoxin B1, groundnut, seeds, quality, contaminatio

Screening of Cowpea (Vigna unguiculata ( L.)Walp) Varieties for Resistance to Leaf Spot in Southern Guinea Savannah Agro- Ecology of Nigeria

Five cowpea varieties (Vigna unguiculata (L.) Walp) namely UAM 09 1055-6, UAM 09 1051-1, IT 99k-573-1-1, IT 90k-277-2 and IT 99k-573-2-1 were investigated for fungi associated with the seed, leaf spot disease incidence and severity in Makurdi (07o 45’- 7o 50’N and 08o 45’ - 08o 50’E ; 98 m)and Otobi (7°07’ - 7°11'N and 8° 05- 8°10'E) in Benue State, Nigeria under natural infection. The effect ofleaf spot incidence and severity on the growth and yield of cowpea varieties were also evaluated. Fungi associated with the seeds and leaf spot lesions were isolated and identified. Diseased leaf samples from the study locations were found to be infected with Fusarium verticillioides, Curvularia lunata, Aspergillus tamarii Kite, Lasiodiplodia theobromae, Aspergillus flavus Link and Aspergillus niger van Tiegh, Pythium spp, Fusarium solani, Macrophomina phaseolina and Phoma sp. Otobi field had significantly higher incidence and severity of leaf spot disease than the Makurdi field. Cowpea variety IT 99k-573-1-1, IT 99k-573-2-1 and IT 90k-277-2 were classified as moderately resistant in Makurdi with a mean incidence of 22.23%, 16.97% and 16.67% respectively while varieties UAM 09 1051-1 and UAM 09 1055-6 were classified as Moderately susceptible and Highly susceptible with mean leaf spot incidence of 41.67% and 99.17% respectively. In Otobi, all the cowpea varieties screened were classified as Susceptible to leaf spot incidence with the exception of variety IT 90k-277-2 which was classified as moderately susceptible to leaf spot disease. Key words: Cowpea, leaf spot, screening, resistant, susceptible