Circulation of Lassa virus across the endemic Edo-Ondo axis, Nigeria, with cross-species transmission between multimammate mice.

We phylogenetically compared sequences of the zoonotic Lassa virus (LASV) obtained from Mastomys rodents in seven localities across the highly endemic Edo and Ondo States within Nigeria. Sequencing 1641 nt from the S segment of the virus genome, we resolved clades within lineage II that were either limited to Ebudin and Okhuesan in Edo state (2g-beta) or along Owo-Okeluse-Ifon in Ondo state (2g-gamma). We also found clades within Ekpoma, a relatively large cosmopolitan town in Edo state, that extended into other localities within Edo (2g-alpha) and Ondo (2g-delta). LASV variants from M. natalensis within Ebudin and Ekpoma in Edo State (dated approximately 1961) were more ancient compared to those from Ondo state (approximately 1977), suggesting a broadly east-west virus migration across south-western Nigeria; a pattern not always consistent with LASV sequences derived from humans in the same localities. Additionally, in Ebudin and Ekpoma, LASV sequences between M. natalensis and M. erythroleucus were interspersed on the phylogenetic tree, but those from M. erythroleucus were estimated to emerge more recently (approximately 2005). Overall, our results show that LASV amplification in certain localities (reaching a prevalence as high as 76% in Okeluse), anthropogenically-aided spread of rodent-borne variants amidst the larger towns (involving communal accommodation such as student hostels), and virus-exchange between syntopic M. natalensis and M. erythroleucus rodents (as the latter, a savanna species, encroaches southward into the degraded forest) pose perpetual zoonotic hazard across the Edo-Ondo Lassa fever belt, threatening to accelerate the dissemination of the virus into non endemic areas.

Isoflavanquinones from Abrus precatorius roots with their antiproliferative and anti-inflammatory effects.

Phytochemical studies on the root of Abrus precatorius Linn. (Fabaceae), leads towards the identification of four undescribed (abruquinones M, N, O, and P), and seven known abruquinones, (abruquinones A, E, B, F, I, D, and G). Spectroscopic analyses (1D, and 2D NMR, HRESI-MS) were used in elucidating structures of the all compounds. Evaluation of anticancer activities of the isolated isoflavanquinones revealed that abruquinones M, and N showed cytotoxicity against oral CAL-27 (IC50 values 6.48 and 5.26 µM, respectively), and colon (Caco-2) cell lines (IC50 values 15.79 and 10.33 µM, respectively). Abruquinone M also inhibited the growth of lung cancer cells (NCI-H460) with IC50 of 31.33 µM. The isolated isoflavanquiones also showed potent anti-inflammatory potential through phagocyte oxidative burst and pro-inflammatory cytokine TNF-α inhibition in vitro. These findings suggest isoflavanquinones from A. precatorius roots as candidates for further research in cancer treatment.

Enzymatic Protein Hydrolysates, and Ultrafiltered Peptide Fractions from Two Molluscs: Tympanotonus fuscatus var. radula (L.) and Pachymelania aurita (M.), with Angiotensin-I-Converting Enzyme Inhibitory and DPPH Radical Scavenging Activities.

CONTEXT: Multifunctional food protein-derived peptides attract a great deal of research interest due to their health-promoting benefits. Particularly, peptides that have both antihypertensive and antioxidant properties are desired, since both effects can be synergistic in prevention of cardiovascular diseases. AIM: The aim of this study was to investigate the angiotensin-I-converting enzyme (ACE) inhibitory and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of two species of the Nigerian periwinkles: Pachymelania aurita and Tympanotonus fuscatus. METHODS: The ACE inhibitory and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of simulated gastrointestinal digestion (SGID) hydrolysates and ultrafiltered (UF) fractions of T. fuscatus var. radula and P. aurita were determined. Human SGID of the protein extracts of T. fuscatus and P. aurita was carried out using pepsin, trypsin, and chymotrypsin, and the hydrolysates were fractionated into two by centrifugal ultrafiltration. The ACE inhibitory and DPPH radical scavenging activities of the crude hydrolysates and UF fractions were tested. The UF permeates were observed to have relatively higher activities and was subjected to gel filtration chromatography on Sephadex G-50. The chromatographic fractions showed absorbance at 215, 225, and 280 nm and were assayed for DPPH radical scavenging activity. RESULTS: The inhibitory effect of the fractions on ACE activity was reported as the minimum concentration of extract that caused 50% of the inhibition (IC50), where the IC50 values of P. aurita UF permeate and P. aurita UF retentate were 65.2 ± 6.4 and 301.9 ± 59.1 µg/ml, respectively, and that of T. fuscatus UF permeate (TFUFP) and T. fuscatus UF retentate were 54.93 ± 2.83 and 291.7 ± 8.6 µg/ml, respectively. CONCLUSION: This study suggests the potential health benefits of consuming T. fuscatus var. radula and P. aurita in health maintenance.

Antioxidant activity of the simulated gastro-intestinal digestion hydrolysate of two edible Nigerian marine molluscs: Tympanatonus fuscatus var radula (L.) and Pachymelania aurita (M.).

The multifunctional nature of antioxidant peptides makes them more attractive candidates as dietary ingredients in health maintenance. Therefore, food protein-derived antioxidant peptides are continuously investigated. This study investigated the in vitro antioxidant properties of hydrolysate and ultrafiltered peptide fractions of Pachymelania aurita and Tympanatonus fuscatus var radula-two commonly consumed marine molluscs known as periwinkles in southern Nigeria. Simulated gastrointestinal digestion (SGID) of soluble proteins of T. fuscatus and P. aurita was carried out using pepsin, trypsin and chymotrypsin, and the SGID hydrolysates were fractionated using a 3 kDa membrane filter. The hydrolysates and their fractions were investigated for anti-lipid peroxidation, hydroxyl radical scavenging activity (HRSA), ferric reducing antioxidant property (FRAP) and metal chelation activity, and they demonstrated clear antioxidant properties in all the assay models used. Low molecular weight fractions of the hydrolysates demonstrated more potent antioxidant activity than higher molecular weight fractions. This is profound in the metal chelation assay, where low molecular weight peptide fractions, T ≤ 3 kDa and P ≤ 3 kDa (IC50 values of 8.10 ± 0.011 and 5.56 ± 0.50 µg/ml respectively) had activity that is similar to that of EDTA (11.84 ± 0.89 µg/ml). Similar activity effects were observed in other assays where there was about 3-fold higher activity in low molecular weight fractions. These results demonstrate the presence of antioxidant peptide(s) in the protein hydrolysates of the periwinkles.

Cytotoxic and Apoptotic Induction Potential of Extracts from Fermented Citrullus vulgaris Thunb. Seeds on Cervical and Liver Cancer Cells.

The anti-cancer activities of many fermented foods and beverages are now scientifically established. Ogiri-egusi is a condiment prepared from fermentation of Citrullus vulgaris (melon) seeds and consumed in many countries of West Africa. Its anti-oxidative and anti-hyperlipidaemic properties have been reported. This study investigated the anti-cancer activities of the aqueous and methanolic extracts from ogiri-egusi. Cytotoxicity was investigated using the MTT and colony-formation inhibition assays while flow-cytometer based Apopercentage assay was used to quantify apoptosis in extracts-treated cervical and liver cancer and normal human fibroblast cells. The inhibitory concentration responsible for killing 50% of cells after 24 h by the aqueous extract in KMST-6, HeLa, and Hep-G2 cells were estimated at 1.610, 1.020, and 1.507 mg/mL respectively. While these values reduced with increasing incubation time in cancer cells it increased in the non-cancer cell. Furthermore, the extract significantly induced apoptosis in HeLa (97 ± 0.18%) and Hep-G2 (73 ± 6.73%) cells. These findings were corroborated by cells morphologic presentations and inhibition of colony formation assay. These findings suggest that the aqueous extract from fermented Citrullus vulgaris seeds might be a nutraceutical with potential anti-cancer properties.

Evaluation of Analgesic Activities of Extracts of Two Marine Molluscs: Tympanotonus fuscatus var radula (Linnaeus) and Pachymelania aurita (Müller).

PURPOSE AND METHODS: In this study, the analgesic activity of the crude alcohol (acetone-methanol) and aqueous (in PBS, pH 7.2) extracts of the marine molluscs, Pachymelania aurita and Tympanotonus fuscatus, has been evaluated using the formalin test (for chronic antinociceptive) and the tail-flick (acute antinociceptive) pain models in male swiss albino mice. RESULTS: The results show that the extracts of P. aurita and T. fuscatus demonstrated high safety margins as single doses of up to 2000 mg/kg bwt proved to be well tolerated and non-lethal, although the alcohol extract of P. aurita caused necrosis in the liver and kidney when administered at a dose level of 2000 mg/kg bwt. In the formalin test, treatment with the aqueous extracts of P. aurita and T. fuscatus as well as the alcohol extract of T. fuscatus 30 min before the subcutaneous injection of 5% formalin to the paw of the mice resulted in a significant time- and dose-dependent reduction in total and phase 2a pain-related behavior and thus nociception. The extracts had no analgesic effect in tail-flick test up to the highest dose tested. CONCLUSION: Hence, the results from both models indicate that the site of their analgesic action is probably peripheral.

Modulation of Blood Coagulation and Hematological Parameters by Crassocephalum crepidioides Leaf Methanol Extract and Fractions in STZ-Induced Diabetes in the Rat.

Diabetes affects the homeostasis of the circulatory system. Crassocephalum crepidioides Benth S. Moore (Asteraceae) is an edible plant locally used in the treatment of wounds, stomach ulcer, and skin-related conditions in Africa and some other parts of the world. This study investigated the effects of C. crepidioides leaf methanol extract and fractions on blood coagulation profile of diabetic Wistar rats. The effect of 100 mg/kg body weight of the methanol extract and partitioned fractions of C. crepidioides on blood coagulation profile of STZ-induced diabetic rats were initially evaluated, while graded concentrations (50-200 mg/kg body weight) of the aqueous and hexane fractions were further tested in diabetic rats against standard drugs aspirin (anticoagulant) and metformin (antidiabetic). Rats were allocated into groups (n = 6) and administration was done orally, once daily for 2 weeks. The methanol extract and fractions of C. crepidioides at concentrations of 50, 100, and 200 mg/kg significantly prolonged the bleeding (58-200%), clotting (65-133%), prothrombin (176-441%), and activated partial thromboplastin (209-518%) times in diabetic rats compared to the control rats (LD50 ≥ 5000 mg/kg). Highest prolongation effects were recorded in the diabetic group treated with 100 mg/kg body weight of the hexane fraction. Plasma calcium concentration and platelet counts of C. crepidioides treated diabetic rats were significantly (P < 0.05) reduced compared to diabetic control rats, while the red blood cells (RBC), hemoglobin concentration, and packed cell volume (PCV) were significantly increased. This study showed that C. crepidioides possess anticoagulant and antianemic activities. The leaves can thus be a potential source of novel anticoagulant and nutraceutical for management of the thrombotic disorder in diabetes and other diseased states.

In vitro anticoagulant effect of Crassocephalum crepidioides leaf methanol extract and fractions on human blood.

BACKGROUND: Blood coagulation is a rapid and efficient process that produces clot formation which requires regulation. A derangement of blood coagulation is a feature of many disease conditions. This study investigated the in vitro effects of Crassocephalum crepidioides Benth S. Moore leaf methanol (crude) extract and its partitioned solvent fractions on blood coagulation of Healthy human volunteers. METHODS: The secondary metabolites from dried and ground C. crepidioides leaves were extracted with 70% methanol, and the concentrated crude extract was subsequently subjected to solvent partitioning with Hexane, Ethyl acetate, and Butanol. Varying concentrations (5-20 mg/mL) of the extract and fractions were tested in vitro on blood coagulation profile; clotting time (CT), prothrombin time (PT), and activated partial thromboplastin time (aPTT) of apparently healthy human volunteers, while phytochemical characterization of the Hexane fraction was done by gas chromatography-mass spectrometry (GC-MS). RESULTS: C. crepidioides leaf methanol extract and fractions significantly (P<0.05) prolonged the clotting time, prothrombin and activated partial thromboplastin times in the blood obtained from the volunteers. The highest prolongation effect was recorded with the Hexane fraction at concentration of 10mg/mL. GC-MS analysis of the Hexane fraction indicated the presence of phytochemicals such as unsaturated fatty acids and esters, phenolic compounds, flavonoids, and coumarin-related compounds known to exhibit antiaggregant, antiplatelet and antimicrobial activities. CONCLUSION: These results showed that C. crepidioides possesses bioactive components with anticoagulant properties which may be exploited in the treatment of blood coagulation disorders.

In vitro antiproliferative studies of extracts of the marine molluscs: Tympanatonus fuscatus Var radula (linnaeus) and Pachymelania aurita (muller).

This study aimed to investigate the antimitotic and antiproliferation activities of crude acetone-methanol and aqueous extracts of two marine molluscs commonly found in the Niger Delta region of Nigeria; T.fuscatus and P.aurita, against human cancerous cell lines (DU145, Hep-2, and HCC1395) cell lines in vitro. The antimitotic activity of the extracts was evaluated using Allium cepa root meristematic cells. Antiproliferative activity of the plant extracts against the cancerous cell lines was compared with normal cell line (VeroE6). Doxorubicin was used as a positive control. Gene expression studies using qPCR for the proapoptotic genes, CASP3, CASP8 and P53 were also carried out. The alcohol extract of T.fuscatus (TFAC) exhibited the most promising activity against all the cancer cell lines tested (DU145 IC50 = 96.48 ± 1.36 µg/ml, HCC 1395 IC50 = 61.44 ± 2.45 µg/ml, Hep2 IC50 = 0.52 ± 0.36 µg/ml) and also had the highest selectivity index of 4.94, 7.78 and 921.97 for DU145, HCC 1395 and Hep-2 cells respectively. Furthermore, TFAC was the only extract that significantly upregulated the expression of caspase 3, caspase 8 and P53. Thus, these findings suggest potential exploitation of TFAC as an anticancer agent.

Broadening Participation in the Sciences within and from Africa: Purpose, Challenges, and Prospects.

Many of Africa's challenges have scientific solutions, but there are fewer individuals engaged in scientific activity per capita on this continent than on any other. Only a handful of African scientists use their skills to capacity or are leaders in their disciplines. Underrepresentation of Africans in scientific practice, discourse, and decision making reduces the richness of intellectual contributions toward hard problems worldwide. This essay outlines challenges faced by teacher-scholars from sub-Saharan Africa as we build scientific expertise. Access to tertiary-level science is difficult and uneven across Africa, and the quality of training available varies from top-range to inadequate. Access to science higher education needs to increase, particularly for female students, first-generation literates, and rural populations. We make suggestions for collaborative initiatives involving stakeholders outside Africa and/or outside academia that could extend educational opportunities available to African students and increase the chance that Africa-based expertise is globally available.

Bioactive metabolites from the South African marine mollusk Trimusculus costatus.

A reinvestigation of extracts of the endemic South African intertidal limpet Trimusculus costatus yielded the known labdane diterpenes 6beta,7alpha-diacetoxylabda-8,13 E-dien-15-ol ( 1) and 2alpha,6beta,7alpha-triacetoxylabda-8,13 E-dien-15-ol ( 2) and three new metabolites, 6beta,7alpha,15-triacetoxylabda-8,13 E-diene ( 3), 3alpha,11-dihydroxy-9,11-seco-cholest-4,7-dien-6,9-dione ( 4), and cholest-7-en-3,5,7-triol ( 5). Chiral derivatization and X-ray analysis were used to confirm the labdane absolute configuration of 2. Compounds 1, 2 and 4 exhibited moderate activity (3-25 microM) against the WHCO1 human esophageal cancer cell line.

Coagulant and anticoagulant activities in Jatropha curcas latex.

Jatropha curcas Linn. (Euphorbiaceae), a medicinal plant commonly grown in the Tropics, is traditionally used as a haemostatic. Investigation of the coagulant activity of the latex of Jatropha curcas showed that whole latex significantly (P<0.01) reduced the clotting time of human blood. Diluted latex, however, prolonged the clotting time: at high dilutions, the blood did not clot at all. This indicates that Jatropha curcas latex possesses both procoagulant and anticoagulant activities. Prothrombin time (PT) and activated partial thromboplastin time (APTT) tests on plasma confirm these observations. Solvent partitioning of the latex with ethyl acetate and butanol led to a partial separation of the two opposing activities: at low concentrations, the ethyl acetate fraction exhibited a procoagulant activity, while the butanol fraction had the highest anticoagulant activity. The residual aqueous fraction had no significant effect on the clotting time of blood and the PT but slightly prolonged the APTT.