Background Carissa bispinosa, Ficus sycomorus, and Grewia bicolar are edible fruit plants that grow in the wild. The plants produce yellow-, red-, and purple-colored fruits and thus can be good sources of flavonoids for fighting oxidative reactions in humans, food, and the pharmaceutical industry. The present study aimed at isolating flavonoids from C. bispinosa, F. sycomorus, and G. bicolar fruits and determining their antioxidant activity using the 2, 2-diphenyl-1- picrylhydrazyl (DPPH) and 2, 2-azino-bis 3-ethylbenz-thiaz-oline-6-sulfonic acid (ABTS) model radical assays. Methods Analytical and preparative thin-layer chromatography was used to isolate flavonoids from the fruits using methanol/chloroform/hexane (7:2:1, v/v/v) as a mobile phase system. The ABTS and DPPH radical scavenging methods were used to test for the antioxidant activity of the samples, using quercetin and catechin as reference standards. Results Thin-layer chromatographic profiling revealed two different types of flavonoids from each plant. C. bispinosa yielded two flavonoid bands, Rf values 0.11 and 0.38; G. bicolar yielded two flavonoid bands, Rf values 0.63 and 0.81; and F. sycomorus also yielded two types of flavonoids, Rf values 0.094 and 0.81. All the extracted flavonoids exhibited significant antioxidant activity of over 80% at a concentration of 200 mg/L. The order of radical scavenging activity for the 200-mg/L samples is G. bicolar Rf (0.81) > C. bispinosa Rf (0.113) > F. sycomorus Rf (0.094) > F. sycomorus Rf (0.047) > C. bispinosa Rf (0.38) > G. bicolar Rf (0.63). G. bicolar (Rf = 0.81) exhibited antioxidant activity that was superior to that of catechin. Conclusion The present study results show that C. bispinosa, F. sycomorus, and G. bicolar contain different flavonoid types with significant antioxidant activity of over 80% at a concentration of 200 mg/L. Therefore, the fruits can be used as a source of natural antioxidants which can be used as nutraceuticals to promote health, as preservatives to delay peroxidation of foods, and as flavoring for packed foods.

Environmental context. Pollution of the aquatic environment by oxytetracycline can lead to microbial resistance thereby compromising the efficacy of current medication regimes. Adsorption by colloidal and sediment particles reduces the rate at which oxytetracycline degrades, whereas the longer the antimicrobial remains in the aquatic environment, the greater the danger of microbial resistance. There is need therefore for a fuller understanding of the kinetics of degradation of oxytetracycline in aquatic ecosystems before measures for mitigating pollution by the antimicrobial can be designed.Abstract. The persistence of oxytetracycline in an aquatic microcosm and distilled water control experiments, was studied over a period of 90 days. An immediate 35 % loss as a result of adsorption by the sediment was observed in the microcosm experiment soon after charging. Subsequently triphasic linear rates of oxytetracycline degradation were observed for both the water phase (3.1 Â 10 À2 , 5.8 Â 10 À3 and 1 Â 10 À3 mg g À1 day À1 ) and sediment phase (4.8 Â 10 À2 , 6.5 Â 10 À3 and 2 Â 10 À4 mg g À1 day À1 ). Degradation is attributed to photolysis and microbial degradation of the free oxytetracycline in solution, and microbial degradation of the colloidal and sediment particle adsorbed speciation forms. The distilled water control exhibited biphasic zero order kinetics attributed to hydrolysis (2 Â 10 À6 mg g À1 day À1 ) and microbial degradation (2.7 Â 10 À3 mg g À1 day À1 ) under dark conditions, and monophasic zero order kinetics attributed to photolysis (6.9 Â 10 À3 mg g À1 day À1 ) under sunlight exposure. A kinetic model that takes into account hydrolysis, photolysis, microbial degradation and adsorption of the antibiotic by colloidal and sediment particles, is presented to account for the monophasic, biphasic and triphasic zero order kinetics observed in the control and microcosm experiments. Possible remediation strategies for mitigating aquatic environments polluted by the antimicrobial are discussed.

Phytochemicals from Dicerocaryum senecioides were studied for hair rejuvenation activity using BalB/c mice. Solvent extractions and thin layer chromatography (TLC) were used to extract and isolate the phytochemicals respectively. Phytochemicals were identi ed by spraying with target-speci c revealing reagents. In vivo hair growth stimulating activity for each extract was tested on denuded dorsal skin of 5-week old BalB/c mice against the controls and the standard drug minoxidil. e parameters used to evaluate hair growth were hair growth completion time, hair length, hair weight, hair follicle length, and relative hair follicle area. e identi ed phytochemicals from the active ethanol extract were steroidal glycosides, triterpenoid glycosides, and avonoid glycosides. Flavonoid glycosides treatment had the uppermost hair rejuvenation capacity as measured by the shortest hair growth completion time (19 days) versus control (29 days) and longest hair length (11.04 mm and 11.86 mm for male and female mice respectively while the control group had 5.15 mm for male mice and 5.33 mm for female mice). Hair growth stimulation by avonoid glycosides was also dependent on dose concentration. It can be concluded from this study that avonoid glycosides extracted from the leaves of Dicerocaryum senecioides have remarkable hair rejuvenation capacity in BalB/c mice. e present results provides insights on the use of Dicerocaryum senecioides for hair rejuvenation in traditional practices and on the potential of the plant as a source of novel compounds that can be used as hair growth promoters.

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The aim of the present work was to establish the kinetics for the degradation of doxycycline in the aquatic environment with a view to arriving at a kinetic model that can be used to predict the persistence of antibiotic with confidence. The degradation of doxycycline in both water and sediment phases of aquatic microcosm experiments, as well as in distilled water control experiments, was studied over a period of 90 days. An initial 21% loss due to adsorption by the sediment was observed in the microcosm experiment soon after charging. Biphasic zero-order linear rates of degradation, attributed to microbial degradation of the free and sediment or colloidal particle-adsorbed antibiotic, were observed for both water phase (2.3 × 10(-2) and 4.5 × 10(-3) μgg(-1) day(-1)) and sediment phase (7.9 × 10(-3) and 1.5 × 10(-3) μgg(-1) day(-1)) of the microcosm experiment. The covered distilled water control experiment exhibited a monophasic zero-order linear rate (1.9 × 10(-3) μgg(-1) day(-1)) attributed to hydrolysis, while the distilled water experiment exposed to natural light exhibited biphasic liner rates attributed to a combination of hydrolysis and photolysis (2.9 × 10(-3) μgg(-1) day(-1)) and to microbial degradation (9.8 × 10(-3) μgg(-1) day(-1)). A kinetic model that takes into account hydrolysis, photolysis, microbial degradation as well as sorption/desorption by colloidal and sediment particles is presented to account for the observed zero-order kinetics. The implications of the observed kinetics on the persistence of doxycycline in the aquatic environment are discussed.

Mining activities are a leading cause of heavy metal contamination of soils and food plants leading to health risk fears. The concentration of heavy metals in soils, Bidens pilosa and Fadogia ancylantha in the vicinity of Bindura town were investigated. Results show that heavy metal concentration of soils and plants found around Bindura town was higher than that of the control area where there were no mining activities suggesting heavy metal contamination. The higher values of heavy metals may place consumers of these plants at health risk with time via bioaccumulation. It is suggested therefore that measures should be taken to lower plant and soil heavy metal accumulation.

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Leaves from Combretum imberbe traditionally used to treat symptoms of malaria in most parts of Southern Africa were studied for interaction of its crude methanolic, ethyl acetate and hexane extracts with hemin a product of hemoglobin degradation in 40% water-dimethylsulphoxide at pH 9, 7.4 and 5 using a spectrophotometric method. It has been established that hemin is the target of antimalaria quinolines thus, interaction of extracts with hemin may represent a crucial initial screening test to define efficacy. Observations were compared to results of interaction of hemin with quinine and artemisia as standards. The present results indicate that hemin complexed more strongly with methanolic extracts than with ethyl acetate and hexane extracts. The binding constants were pHdependent. The present results are interesting because the crude extracts share a similar mode of action with quinine and artemisia with an isosbetic point at 352 nm. Methanolic extract showed better affinity for hemin than artemisia with complexation constants (K) of 1.011 × 10 4 and 0.612 × 10 4 M, respectively. However, quinine showed better affinity than methanolic extract with K of 1.101 × 10 4 M.