Prevalence and sources of polychlorinated biphenyls in the atmospheric environment of Lake Victoria, East Africa.

The large surface area of Lake Victoria (about 68,800 km) makes it vulnerable to high atmospheric deposition of chemical pollutants. We present measurements of polychlorinated biphenyls (PCBs) from the lake's atmospheric environment. High volume air (24 h) samples were collected within the northern Lake Victoria watershed in Uganda over two periods; 1999-2004 [at Kakira (KAK) and Entebbe (EBB)] and 2008-2010 (at EBB only).

Legacy and currently used pesticides in the atmospheric environment of Lake Victoria, East Africa.

The Lake Victoria watershed has extensive agricultural activity with a long history of pesticide use but there is limited information on historical use or on environmental levels. To address this data gap, high volume air samples were collected from two sites close to the northern shore of Lake Victoria; Kakira (KAK) and Entebbe (EBB). The samples, to be analyzed for pesticides, were collected over various periods between 1999 and 2004 inclusive (KAK 1999-2000, KAK 2003-2004, EBB 2003 and EBB 2004 sample sets) and from 2008 to 2010 inclusive (EBB 2008, EBB 2009 and EBB 2010 sample sets).

Historical deposition of persistent organic pollutants in Lake Victoria and two alpine equatorial lakes from East Africa: Insights into atmospheric deposition from sedimentation profiles.

Information on historical deposition of persistent organic pollutants (POPs) for African lakes is very limited. We investigated historical deposition trends and sources of POPs in sediment cores from Lakes Victoria (SC1), Bujuku (Buju2) and Mahoma (Maho2). The latter two lakes are situated in the Rwenzori mountain range in western Uganda.

Antiplasmodial compounds from the stem bark of Neoboutonia macrocalyx pax.

Ethnopharmacological Relevance: The plant Neoboutonia macrocalyx has been reported in traditional medicine to be used in the treatment of malaria.

Aim Of The Study: To study the in vitro antiplasmodial activity of compounds from the stem bark of Neoboutonia macrocalyx.

Materials And Methods: Compounds were extracted and purified from stem bark of Neoboutonia macrocalyx and their structure identified and confirmed by spectroscopic methods.

Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polybrominated diphenyl ethers in sediments and fish species from the Murchison Bay of Lake Victoria, Uganda.

Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polybrominated diphenyl ethers (PBDEs) were analyzed in sediments and fish from the Murchison Bay of Lake Victoria by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). Average concentrations of total (Σ) PCDD/Fs and ΣPBDEs in sediments ranged from 68.8 to 479 pg g(-1) dry weight (dw) and 60.

Purple anthocyanin colouration on lower (abaxial) leaf surface of Hemigraphis colorata (Acanthaceae).

The functional significance of anthocyanin colouration of lower (abaxial) leaf surfaces is not clear. Two anthocyanins, 5-O-methylcyanidin 3-O-(3″-(β-glucuronopyranosyl)-β-glucopyranoside) (1) and 5-O-methylcyanidin 3-O-β-glucopyranoside (2), were isolated from Hemigraphis colorata (Blume) (Acanthaceae) leaves with strong purple abaxial colouration (2.2 and 0.

Medicinal plants used in malaria treatment by Prometra herbalists in Uganda.

Ethnopharmacological Relevance: The aim of the survey was to document medicinal plants used in malaria treatment by Prometra (Promocion de la medicina tradicional amazonica) Traditional Medical Practitioners (TMPs) of Uganda and for search of new antiplasmodial herbal medicines (HMs) for further phytochemical analysis.

Materials And Methods: In this study, semi structured guided open and close ended questionnaires were used. Focus group discussions were conducted and key informants were chosen within the TMPs who helped in further discussions of how the herbal remedies where collected, prepared and administered.

Cycloartane triterpenes from the leaves of Neoboutonia macrocalyx L.

Neoboutonia macrocalyx is used by people in south western Uganda around Kibale National Park in the treatment of malaria. Phytochemical investigation on the leaves of this plant led to the isolation of nine cycloartane triterpenes (1-9) and one phenanthrene; 7-methoxy-2,8 dimethyl-9,10-dihydrophenantherene-3,6 diol (10) along with three known compounds which included 22-de-O-acetyl-26-deoxyneoboutomellerone (11), mellerin B (12) and 6-hydroxystigmast-4-en-3-one (13). The chemical structures of the compounds were established mainly through a combination of spectroscopic techniques.

Polychlorinated biphenyls in sediments and fish species from the Murchison Bay of Lake Victoria, Uganda.

Polychlorinated biphenyls (PCBs) were determined in sediments and two fish species collected from the Murchison Bay in Lake Victoria, using high resolution gas chromatography coupled to a high resolution mass spectrometer. Total PCB concentrations (Σ18PCBs) varied widely with mean values ranging from 777 to 4325pg g(-1) dry weight (dw) for sediments and 80 to 779pg g(-1) wet weight (ww) for fish. The PCB levels in the sediments were significantly higher at the station closest to Nakivubo channel, presumably due to effluents discharged by the channel, which may contain domestically produced commercial PCB mixtures.

Polychlorinated biphenyls and hexachlorocyclohexanes in sediments and fish species from the Napoleon Gulf of Lake Victoria, Uganda.

Polychlorinated biphenyls (PCBs) and hexachlorocyclohexanes (HCHs) were analyzed in surface sediments (<30 cm depth) and two fish species: Nile perch (Lates niloticus) and Nile tilapia (Oreochromis niloticus). The samples were collected from the Napoleon Gulf on the northern shore of Lake Victoria. The analysis was done using a gas chromatograph (GC) coupled to a high resolution mass spectrometer for PCBs and a GC equipped with an electron capture detector for HCHs.

Polybrominated diphenyl ethers and alternative flame retardants in air and precipitation samples from the northern Lake Victoria region, East Africa.

High volume air and precipitation samples were collected close to the shore of Lake Victoria at Entebbe, Uganda, between October 2008 and July 2010 inclusive. Polybrominated diphenyl ethers (PBDEs) and alternative flame retardants (AFRs) were analyzed by GC-MS. BDEs 47, 99, and 209 were the predominant PBDEs with mean concentrations (in air) of 9.

Anti-bacterial activities and phytochemical screening of extracts of different parts of Thalictrum rhynchocarpum.

Parts of the plant Thalictrum rhyncocarpum are used in herbal medicine in Kenya to treat various infections. The aim of this study was to evaluate in-vitro anti-bacteria activities and phytochemical profiles of solvent extracts of the leaves, stem bark and root of Thalictrum rhyncocarpum against Bacillus subtilis-6633, Staphylococcus aures-SG 511, Escherichia coli SG 458, Pseudomonus aeruginosa-K799/61 and Mycobacterium vaccae-10670. Anti-bacterial activity tests were carried out using disc diffusion assay and tube dilution technique, and phytochemical screening was carried out through Thin Layer Chromatography.

PCDD/Fs and dioxin-like PCBs in fish species from Lake Victoria, East Africa.

Two commercially important fish species, Nile perch (Lates niloticus) and Nile tilapia (Oreochromis niloticus) belonging to different trophic levels were collected from the Napoleon Gulf and Thurston Bay in Lake Victoria. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) were extracted from the fish muscles and livers using the (13)C isotope dilution method, followed by multiple column chromatography clean-up. Analysis was achieved by a high resolution gas chromatography coupled with a high resolution mass spectrometer.

PCDD/Fs and dioxin-like PCBs in surface sediments from Lake Victoria, East Africa.

Surface sediments (<60 cm) from the Napoleon Gulf and Thurston Bay on the northern shore of Lake Victoria were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs). Fifteen PCDD/Fs and eleven dl-PCBs were found in 75.5% of the samples.

Atmospheric concentrations of polycyclic aromatic hydrocarbons in the watershed of Lake Victoria, East Africa.

In the first study of its kind in Africa, PAHs were measured in high volume (24 h) air samples collected from two sampling stations, at Kakira and Entebbe (KAK and EBB, respectively) within the Lake Victoria watershed in Uganda, to assess source contributions and generate a baseline reference data set for future studies in the East African region. Sampling was conducted over two periods [2000-2004 (KAK and EBB1) and 2008-2010 (EBB2)]. The samples were extracted by accelerated solvent extraction and analyzed for 30 PAHs by GC-MS.

The antiplasmodial and radical scavenging activities of flavonoids of Erythrina burttii.

The acetone extract of the root bark of Erythrina burttii showed in vitro antiplasmodial activity against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC(50) values of 0.97 ± 0.2 and 1.

Toxicarioside M, a new cytotoxic 10β-hydroxy-19-nor-cardenolide from Antiaris toxicaria.

A new 10β-hydroxy-19-nor-cardenolide, named toxicarioside M (1), was isolated from the trunk bark of Antiaris toxicaria (Pers.) Lesch (Moraceae), along with six known cardenolides (convallatoxin (2), convallatoxol (3), convalloside (4), 3-O-ß-D-xylopyranosylstrophanthidin (5), glucostrophanthidin (6) and strophanthidin (7)). Their structures were elucidated on the basis of HR-MS(n) analysis, spectroscopic methods (IR, UV, 1D and 2D NMR) and by comparison with data reported in the literature.

New anthocyanidin and anthocyanin pigments from blue plumbago.

Phytochemical investigations of blue plumbago ( Plumbago auriculata Poir. syn. Plumbago capensis Thunb.

Organochlorine pesticide in fresh and pasteurized cow's milk from Kampala markets.

Fresh and pasteurized milk samples from Kampala markets were analyzed for organochlorine pesticides using a gas chromatograph equipped with an electron capture detector. Five organochlorine pesticides, namely; aldrin, dieldrin, endosulfan, lindane, DDT and its metabolites were detected in the milk samples and confirmed with a gas chromatograph equipped with a mass spectrometer [GC-MS]. The mean values are expressed in mgkg(-1) milk fat (mf) basis.

Traditional plants used for medicinal purposes by local communities around the Northern sector of Kibale National Park, Uganda.

Ethnopharmacological Relevance: The study was done to establish medicinal plants used in the treatment of various diseases by the people in the Northern sector of Kibale National Park in western Uganda. It was also aimed at establishing the plant parts used and the mode of preparation of remedies. These plants create a basis for phytochemical evaluation which can lead to the discovery of biologically active compounds that can be used as starting materials in the development of new drugs targeting selected diseases such as malaria.

Organochlorine pesticide residues in sediments from the Uganda side of Lake Victoria.

Organochlorine (OC) residues were analysed in 117 sediment samples collected from four bays of the Uganda side of Lake Victoria. The sediments were collected with a corer at a depth of 0-20 cm, and extracted for OC residues using a solid dispersion method. The extracts were cleaned using gel permeation chromatography and analysed for pesticide residues using a gas chromatograph (GC) equipped with an electron capture detector.

Anthocyanins with unusual furanose sugar (apiose) from leaves of Synadenium grantii (Euphorbiaceae).

Four anthocyanins, cyanidin 3-O-(2''-(5'''-(E-p-coumaroyl)-beta-apiofuranosyl)-beta-xylopyranoside)-5-O-beta-glucopyranoside, cyanidin 3-O-(2''-(5'''-(E-p-coumaroyl)-beta-apiofuranosyl)-beta-xylopyranoside), cyanidin 3-O-(2''-(5'''-(E-caffeoyl)-beta-apiofuranosyl)-beta-xylopyranoside) and cyanidin 3-O-(2''-(5'''-(E-feroyl)-beta-apiofuranosyl)-beta-xylopyranoside) were isolated from leaves of African milk bush, (Synadenium grantii Hook, Euphorbiaceae) together with the known cyanidin 3-O-beta-xylopyranoside-5-O-beta-glucopyranoside and cyanidin 3-O-beta-xyloside. The four former pigments are the first reported anthocyanins containing the monosaccharide apiose, and the three 5'''-cinnamoyl derivative-2''-(beta-apiosyl)-beta-xyloside subunits have previously not been reported for any compound.

Organochlorine pesticides in soils from south-western Uganda.

Organochlorine (OC) residues were analysed in soil samples collected from Kihiihi sub-county, Kanungu District, which is located in south-western Uganda. Mabira Central Forest Reserve which is located in central Uganda was used as a reference site in this study. The samples were collected at 15-20 cm depths below the soil surface and extracted with organic solvents.

Ugandenial A, a new drimane-type sesquiterpenoid from Warburgia ugandensis.

One new drimane-type sesquiterpenoid, named ugandenial A (1), was isolated from the ethyl acetate extract of the bark of Warburgia ugandensis (Canellaceae) together with eight known drimane-type sesquiterpenoids: 11alpha-hydroxycinnamosmolide (2), warburganal (3), polygodial (4), mukaadial (5), dendocarbin A (6), 9alpha-hydroxycinnamolide (7), dendocarbin L (8) and dendocarbin M (9). Their structures were established by detailed spectroscopic analysis. In addition a keto-enol equilibrium was demonstrated for compound 1 through a detailed NMR analysis run in CD(2)Cl(2) at 190 K.

DDT and metabolites in fish from Lake Edward, Uganda.

This paper presents results based on determination of residue levels of 1,1,1-trichloro-2,2-bis[p-chlorophenyl]ethane (DDT) and its metabolites in five fish species from Rwenshama landing site on Lake Edward, Uganda. The residue levels were analysed by using a GC-ECD and confirmed by GC-MS. The DDT residues detected in fish samples from Lake Edward were p,p'-DDT, o,p'-DDT, p,p'-DDE, o,p'-DDE, p,p'-DDD and o,p'-DDD.