Recent development in nanoscience and nanotechnology has contributed to the wide applications of metal and metal oxides nanoparticles in several field of sciences, research institutes and industries. Among all metal oxides, copper oxide nanoparticles (CuONPs) has gained more attention due to its distinctive properties and applications. The high cost of reagents, equipment and environmental hazards associated with the physical and chemical methods of synthesizing CuONPs has been a major setback. In order to puffer solution to the aforementioned challenges by reducing environmental pollution and production of cheaper nanoparticles with good properties and efficiency, this review focus on collection of comprehensive information from recent developments in the synthesis, characterization and applications from previous scientific findings on biological method of synthesizing CuONPs due to the acclaimed advantages of been cheap, environmentally friendly, convenient and possibility of been scale up in into large scale production reported by numerous researchers. Our finding also support the synthesis of CuONPs from plant sources due to relative abundance of plants for the production of reducing and stabilizing agents required for CuONPs synthesis, potential efficiency of plant biomolecules in enhancing the toxicity effect of CuONPs against microbes, prevention of environmental pollution due of nontoxic chemicals and degradation effectiveness of CuONPs synthesized from plant sources. Furthermore, this study provide useful information on the rapid synthesis of CuONPs with desired properties from plant extracts.

The delinquent peril of bacterial infections affecting human kind is becoming unbearable. This study was embarked on to investigate the antimicrobial activity of biosynthesized silver nanoparticles (AgNPs) using Garcinia kola bark extract against some bacteria strains. Fresh barks of Garcinia kola were obtained from the “Gbeleju” farm land in Irele town in Ondo state region of Nigeria. Exactly 0.4 g of previously pulverized bark of Garcinia kola was immersed into 20 mL of distilled water and heated at 60–70°C for 10 minutes yielding the extract. The biosynthesized nanoparticle was characterized with UV spectroscope, Fourier infrared spectroscope (FTIR), transmission electron microscope (TEM), and energy dispersive X-Ray analyzer (EDX). Then, 0.2 g of the silver nanoparticles was dissolved in 2 ml of water to yield 100 mg/ml of the stock solution which was further diluted for the antibacterial analysis via the disc diffusion method. The result obtained from the analytical characterization of the biosynthesized silver nanoparticles revealed a spherical particle shape, particle size in the range of 12.23 to 27.90 nm with an average size of 20.07 nm via TEM analysis. The FTIR analysis confirmed the presence of -OH functional group for the stabilization of the silver nanoparticles formed due to the broad peak at wavelength 3324.52 and 3344.21 cm−1. The EDX analysis revealed carbon, nitrogen, oxygen, aluminum, potassium, copper, and silver as the elements present in the nanoparticles. Results obtained from the antibacterial screening of the biosynthesized AgNPs showed inhibitory potential that are capable of obstructing the growth of the test bacteria. This investigation ascertained the biosynthesized AgNPs as a remedy for curing bacterial infections and also a promising source for novel antibacterial agent.

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The conviction that herbal drugs have enormous health benefits has led to increase the rate of their consumption by Nigerians. The aim of this study was to assess the carcinogenic property of some popularly consumed anti-diarrheal herbal drugs via polycyclic aromatic hydrocarbons (PAHs) quantification. Three prevalent anti-diarrhea herbal drugs , Odunmo herbal drug (Hibiscus rosa-sinensis and Bacopamonnieri), Orogun herbal mixture (Hibiscus sabdariffaI and Hedera helix), and Alora herbal syrup (Aloe vera and Hibiscus sabdariffaI) were bought for the purpose of this study and they were coded as samples A, B, and C, respectively. The ultrasonic extraction of the herbal drugs was carried out using standard procedures. The crude extracts obtained were purified using a chromatographic method. The concentrations of PAHs were quantified using gas chromatography flame ionization detector (GCFID). The diagnostic indices, group distribution, toxicity equivalence and exposure dosage were estimated. The cancer risk values were theoretically speculated based on concentrations of PAHs in the tested herbal drugs, associated with the published estimates of each concentration to cause cancer and the calculated exposure doses of the anti-diarrhea herbal drug samples were within three age groups (children, Preteen and adult). The highest concentration of total PAHs was observed in sample A (58.2815mg/kg) and the lowest concentration in sample B (44.1898mg/kg), but the concentration of total PAHs in sample C was 47.4169 mg/kg. The highest percentage of carcinogenic PAHs in the anti-diarrheal herbal drugs was found in sample C (48.66%) and the lowest in sample B (38.17%). The diagnostic indices confirmed a pyrogenic source of PAHs. Group distribution of PAHs showed that the herbal drugs are weakly carcinogenic due to high concentrations of low and moderate molecular weight PAHs. The cancer risk estimated for all the age groups where below the limit established by the United State Environmental Protection Agency (USEPA) for cancer (1 x 10-6). This ascertained that the use of these herbal drugs cannot cause cancer. However, consumers of these herbal drugs should take necessary precautions as excessive intake can lead to dangerous health implications.