pH-responsive Photinia glabra-zinc oxide-protoporphyrin IX nanoconjugates with enhanced cellular uptake for photodynamic therapy towards cancer cells.

Background: Photodynamic therapy (PDT) of cancer has been limited by the poor solubility of most photosensitizers, use of high drug dosages, and the pH difference between the tumor tissue microenvironment (slightly acidic) and the bloodstream. These affect cellular uptake, selectivity and singlet oxygen generation. Materials & methods: We formulated Photinia glabra-green synthesized zinc oxide-protoporphyrin IX (PG-ZnO-PP) nanoconjugates by conjugating the ZnO nanoparticles enriched with amino groups and PP. Results: PG-ZnO-PP nanoconjugates showed higher rate of reactive oxygen species generation, improved cellular uptake in the acidic pH and lower IC50 toward Eca-109 cells for PDT. Conclusion: PG-ZnO-PP nanoconjugates are a potential solution to reducing drug dosage of PP through improved drug uptake, for enhanced targetability and reduced skin photosensitivity with improved PDT efficacy.

The progress of treating cancer using light-sensitive drugs and laser light of known wavelength has been limited by the poor solubility of most light-sensitive drugs, the use of high drug dosages and the slightly acidic environment within the cancerous tissues compared with normal blood in the body. These affect the ability of drugs to accumulate in cancerous cells, and not the normal cells, and the ability to produce the oxygen species that are toxic to the cancerous cells. In this paper, we prepared nanoparticles from zinc acetate using Photinia glabra (PG) fruit extract which were then used to chemically react with a light-sensitive drug called protoporphyrin IX (PP) to formulate small particles known as PG­zinc oxide (ZnO)­PP nanoconjugates. Our results showed that PG­ZnO­PP nanoconjugates had the ability to produce the toxic oxygen particles at a high rate and in good quantity. They also had a higher capability to accumulate in the cancerous cells at a pH below 7 with lower values of the drug needed to cause 50% of cell death toward the cancerous cells which affect the tube that connects from the throat to the stomach when projected with laser light. We could consider PG­ZnO­PP nanoconjugates to serve as a potential solution for reducing the dosage of PP needed to treat cancer in the presence of laser light, and at the same time they can help to reduce the skin-related side effects for patients after treatment when exposed to light.

Antibacterial and anticancer activities of green-synthesized silver nanoparticles using Photinia glabra fruit extract.

Aims: We prepared Photinia glabra (PG) aqueous fruit extract, utilized it to synthesize silver nanoparticles (PG-Ag NPs) and evaluated the antibacterial and anticancer activities of the nanoparticles (NPs). Materials & methods: Silver nitrate aqueous solution was reduced to PG-Ag NPs using aqueous PG fruit extract. NP shape, size, composition and functionalization were determined using transmission electron microscopy, x-ray photoelectron spectroscopy, Fourier transform infrared and x-ray diffraction. Results & conclusions: PG-Ag NPs were spherical, approximately 39-77 nm-sized, functionalized surfaces with notable antibacterial activity against both Escherichia coli and Staphylococcus aureus, with an MIC <30 ug/ml and cytotoxicity toward esophageal cancer cells, with IC50 values less than 20 ug/ml. PG-Ag@rt NPs have been shown to be a potent antibacterial and anticancer agent, and their enriched particle surfaces can be conjugated with other compounds for multibiomedical applications.

The present study reports for the first time the preparation of Photinia glabra (PG) aqueous fruit extract and its use for the synthesis of smaller silver particles (PG-Ag NPs) from bulk aqueous silver nitrate solution (AgNO₃). The preparation followed the reduction ability of PG fruit extract phytochemical under different preparation conditions: at room temperature (PG-Ag@rt), at 70°C (PG-Ag@70) and in the presence of cerium oxide at 70°C (PG-Ag+CeO₂@70). The prepared smaller particles were found using transmission electron microscopy to be spherical in shape with sizes 39, 77 and 44 nm for PG-Ag@rt, PG-Ag@70 and PG-Ag+CeO₂@70, respectively. The NPs contained different functional groups on their surfaces due to the capping ability of PG fruit extract components. Among all, PG-Ag@rt NPs showed strongest antibacterial activity against Escherichia coli and Staphylococcus aureus with MIC 7.0 µg/ml and 28.0 µg/ml, respectively, and commendable anticancer activity toward Eca-109 cancer cells with IC₅₀ less than 20 ug/ml.

Organochlorine pesticide residues in Uganda's honey as a bioindicator of environmental contamination and reproductive health implications to consumers.

Honey has multifaceted nutritional and medicinal values; however, its quality is hinged on the floral origin of the nectar. Taking advantage of the large areas that they cover; honeybees are often used as bioindicators of environmental contamination. The focus of the present paper was to examine the quality of honey from within the vicinity of an abandoned pesticide store in Masindi District in western Uganda. Surficial soils (<20 cm depths) and honey samples were collected from within the vicinity of the abandoned pesticide store and analysed for organochlorine pesticide (OCP) residues using gas chromatograph coupled to an electron capture detector (GC-ECD). The mean level of ∑DDTs in all the soil samples was 503.6 µg/kg dry weight (d.w). ∑DDTs contributed 92.2% to the ∑OCPs contamination loads in the soil samples, and others (lindane, aldrin, dieldrin, and endosulfans) contributed only 7.8%. Ratio (p, p'-DDE+p, p'-DDD)/p, p'-DDT of 1.54 suggested historical DDT input in the area. In all the honey samples, the mean level of ∑DDTs was 20.9 µg/kg. ∑DDTs contributed 43.3% to ∑OCPs contamination loads in the honey samples, followed by lindane (29.8%), endosulfans (23.6%) and dieldrin (3.2%), with corresponding mean levels of 14.4, 11.4 and 1.55 µg/kg, respectively. Reproductive risk assessment was done based on the hazard quotient (HQ) and hazard index (HI) procedure. In our study, the calculated HIs for adults (102.38), and children (90.33) suggested high potential health risks to the honey consumers. Lindane, endosulfan and p, p'-DDD detected in the honey samples at levels exceeding the acute reference dose (ARfD) are known risk factors for spontaneous abortion, reduced implantation, menstrual cycle shortening, impaired semen quality, and prostate cancer in exposed individuals and experimental animal models.

Concentrations and sources apportionment of polycyclic aromatic hydrocarbons in sediments from the Uganda side of Lake Victoria.

This study presents the levels and possible sources of selected polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Napoleon Gulf and Murchison Bay of Lake Victoria. Sediment samples were extracted and cleaned up for PAHs using UNEP, 1992, and EPA method 3630C protocols. The analysis of sample extracts was carried out using a gas chromatograph coupled to a mass spectrometer. Fifteen congeners, mostly the high molecular weight PAHs (HPAHs) (4-6 rings) were detected. Total (∑) concentrations varied from 44.2 to 80.2 ng g-1 dry weight (d.w.) at the Napoleon Gulf, while those at the Murchison Bay ranged from 17.0 to 55.0 ng g-1 d.w. Statistical analysis showed no significant difference in the concentrations of PAHs among sites (p < 0.05, ANOVA). It was noted that the concentrations for most sampling sites were far below the lowest effect levels based on the Sediment Quality Guidelines, except for one station at the Napoleon Gulf. Principal component analysis and diagnostic ratios indicated that PAHs of combustion and petroleum origin were dominant and brought about mainly by atmospheric deposition.

Variation in fatty acid composition in muscle and heart tissues among species and populations of tropical fish in Lakes Victoria and Kyoga.

The composition of the fatty acids in muscle and heart tissue of seven fish species, Nile perch (Lates niloticus), Nile tilapia (Oreochromis niloticus), marbled lungfish (Protopterus aethiopicus), African catfish (Clarias gariepinus), Lake Victoria squeaker (Synodontis victoriae), Bagrus docmas, and Tilapia zilli, from two locations in Lake Kyoga and one location in Lake Victoria was chemometrically determined. The muscle tissue was very lean, with an average of 3.4 mg total fatty acids per g tissue. The lipid level in the heart tissue was approximately five times higher than in the muscle tissue, with an average of 15.5 mg total fatty acids per g tissue. The n-3/n-6 level in the muscles was 1.7 +/- 0.7 and in the heart tissue 1.0 +/- 0.4. The muscle tissue contained an average of 46 mg cholesterol per 100 g, and the heart tissue contained about five times as much. Plasmalogens were detected in 7-8% of the amounts of total fatty acids in both muscle and heart tissue. The seven species had large differences (P < 0.05) in the fatty acid composition for both muscle and heart tissue. Within the species there were differences between fish from the populations in the three locations, although the population differences were smaller than the species differences. These differences appear to be controlled more closely by genetics/transcriptomics than by the diet.