Advanced Journal of Chemistry, Section B: Natural Products and Medical Chemistry
Volume:6 Issue: 4, Autumn 2024

In this study, the chemical composition of each agrowaste sample was analysed for cellulose, lignin, ash, and moisture content. Three agrowaste samples—corn husk, pineapple crown, and plantain stalk—were sun-dried and chipped for easier digestion. The effect of the catalyst, H₂SO₄, was assessed by pulping 10g of each sample with 0%, 0.5%, 1%, and 1.5% H₂SO₄. At the end of the experiment, three types of paper were produced from the different agrowaste samples; each of them demonstrates good brightness. The mechanical properties of the pulp were measured, yielding the following results for corn husks (grammage: 356.25 g/m², thickness: 0.35 mm, tensile strength: 25.675 kN/m², tear index: 2.88 Nm²/g, modulus of elasticity: 151.03 kN/m², and elongation at break: 3.4mm), for pineapple crown (grammage: 231.25 g/m², thickness: 0.13 mm, tensile strength: 21.05 kN/m², tear index: 3.64 Nm²/g, modulus of elasticity: 155.93 kN/m², elongation at break: 2.2 mm), and for plantain stalk (grammage: 325.25 g/m², thickness: 0.07 mm, tensile strength: 23.625 kN/m², tear index: 2.91 Nm²/g, modulus of elasticity: 393.75 kN/m², and elongation at break: 1.20 mm). In summary, agrowastes present a feasible alternative to wood for papermaking. The Acetosolv pulping method yields a higher amount of pulp while minimizing environmental impact.

The antioxidant capacity and total phenolic content of extracts from ripe Dovyalis abyssinica fruits were examined in this work. The fruits’ chemistry was further detailed after isolation and purification studies. Methanol and ethyl acetate extracts yielded 921.79 ± 1.63×10-³ mg GAE/100g and 517.95 ± 1.4×10-³ mg GAE/100g phenolic content. In contrast, the methylene chloride and hexane extracts gave 261.54 ± 1.0×10-3 mg GAE/100g and 24.36 ± 8.2×10-3 mg GAE/100g, respectively. From these extracts, data on the IC50 of the four extracts showed significantly higher antioxidant capacity in the methanol extract (4.4 μg/mL) than that of the ethyl acetate, methylene chloride, and hexane extracts (8.4 μg/mL, 28.8 μg/mL, and 55.8 μg/mL, respectively). Phytochemical analysis gave three known compounds: betulinic acid (1), 3,4-bis(4-hydroxybenzoyl)-1,5-anhydro-D-glucitol l (2), and sitosterol (3) via NMR spectroscopic techniques. The nutritional potential of these fruits was validated by their chemical profile, providing a solid foundation for their future exploitation. The three compounds are new reports, specifically from the fruits of D. abyssinica. The anhydroglucitol was particularly interesting, as it is a phenol capable of antioxidant activity. To the best of our knowledge, this is the second time that this compound has been reported through this study.

For decades, the synthesis of chiral molecules has been a paramount focus in chemical research, driven by their profound impact on various industries. The quest for chiral molecule synthesis has propelled the development of asymmetric hydrogenation, a versatile technique that combines precision, efficiency, and flexibility. Chiral molecules, characterized by non-superimposable mirror images, require precise stereochemistry, making asymmetric hydrogenation a crucial tool. The synthesis of complex molecules with precise stereochemistry is essential for developing effective pharmaceuticals and biologically active compounds. Transition metal catalysts (Ru, Rh, and Ir) have demonstrated exceptional efficacy, while organocatalytic and biocatalytic approaches have expanded substrate scope and application possibilities, offering sustainable and green chemistry solutions. Recent advances in asymmetric hydrogenation have achieved high enantioselectivity, paving the way for drug discovery and development breakthroughs. Despite significant progress, challenges persist, and addressing these hurdles will require innovative solutions. This article provides a comprehensive overview of asymmetric hydrogenation, exploring its methods, catalysts, and applications while highlighting recent developments, addressing ongoing challenges, and exploring future directions in the pursuit of efficient and sustainable chiral synthesis.

This study evaluated the concentrations of various air pollutants, including Carbon Monoxide (CO), Hydrogen Sulphide (H2S), Carbon Dioxide (CO2), Volatile Organic Compounds (VOCs) and Nitrogen Dioxide (NO2), originating from vehicular emissions. In addition, the ambient air particulate matter (PM2.5 and PM10) levels were measured across seven market sites in Owerri. These markets were chosen due to their high congestion during the day, attributed to dense vehicular traffic, residential buildings, and human activities. Measurements were conducted over three-hour periods in the morning (6:00 a.m.-9:00 a.m.) and evening (4:00 p.m.-7:00 p.m.), which are peak times for human and vehicular movement. The results indicated that the highest H2S concentration (0.04-0.54 ppm) was found at Orji market, well below the AEGL-3 limit of 33 ppm. CO2 levels peaked at 1027-1088 ppm at Relief market, exceeding the ambient standard of 314 ppm, while the lowest levels (810-960 ppm) were recorded at Obinze Market. NO2 concentrations were highest (0.132-0.20 ppm) at Orji and Relief markets, surpassing the NAAQS limit of 0.100 ppm. The highest CO concentration (14-15.5 ppm) was observed at Relief market, below the NAAQS limit of 35 ppm. VOC levels were highest (0.8-1.0 mg/m³) at Obinze Market, exceeding the permissible target value of 0-0.75 ppm. PM2.5 and PM10 concentrations were highest at World Bank Market (0.40-0.50 mg/m³), exceeding the NAAQS and WHO standards of 0.15 mg/m³. The study concludes that vehicular emissions and human activities significantly contribute to air pollution in the environment. Atmospheric conditions such as temperature, dew point, humidity, wind pressure, and wind speed were also analyzed.

The global appeal of biofuels is increasing due to rising energy demands and the depletion of fossil fuel resources. Biodiesel stands out as a promising alternative to petroleum diesel, offering a cleaner energy solution. This study addresses key challenges associated with biodiesel, such as reduced calorific value, high nitrous oxide emissions, and production costs, as well as the environmental impact of petroleum diesel, including global warming.This research focuses on the development of a novel biobased catalyst derived from palm kernel shell and eggshell. The carbon-based biomass, primarily waste palm kernel shell, was pyrolyzed to produce the catalyst. Characterization of the catalyst was performed using scanning electron microscopy (SEM), X-ray fluorescence (XRF), and Fourier transform infrared spectroscopy (FTIR). The catalyst was synthesized via the incipient wetness impregnation (IWI) technique, resulting in a bifunctional catalyst suitable for the transesterification process.The catalyst demonstrated high efficiency in the transesterification process for biodiesel production. Optimal conditions yielded an 88.14% biodiesel conversion at an oil-to-methanol molar ratio of 1:14, catalyst loading of 5 wt.%, reaction temperature of 70°C, and reaction time of 99.244 minutes. The synthesized biodiesel met the ASTM D6751 standards as specified by the International Organization for Standardization (ISO).

Antibiotic resistance and worries about the use of synthetic drugs have been serious concerns in the scientific community. Researchers are working to develop alternatives to synthetic drug use, and to lessen the negative impact that these drugs have on the systems of the human body. Research indicates that Ficus elastica contains a number of bioactive substances, including flavone, which, when tested on a clinical isolation, had antibacterial activity. In this work, three solvents—ethanol, chloroform, and n-hexane—were used to extract the qualitative phytochemical components, such as alkaloids, tannins, saponins, terpenoids, and phlobatannins. On extracts of Ficus elastica in various solvents, the effects of common antibiotic discs including gentamycin, azithromycin, ciprofloxacin, nitrofurantoin, and ofloxacin were investigated. Ficus elastica crude ethanol, n-hexane, and chloroform extracts were statistically significant when compared to the control and standard antibiotic discs at P<0.001. The most effective crude extract, both in terms of antibacterial action and phytochemical analyzes, is n-hexane. Ficus elastica possesses high antibiotic activity against pathogenic bacterial isolates, according to the current study's findings, and phytochemical analysis revealed that this activity is mediated by substances present as secondary metabolites. Thus, disorders brought on by the test bacterial pathogens can be treated with Ficus elastica extract.