Asian Journal of Green Chemistry

Abstract Many antibiotics available at the clinic are natural products or derivatives of these products that originate from bacteria, fungi, plants, and animals. After the discovery of penicillin by Alexander Fleming in 1928, the discovery and extraction of antibiotics from natural sources expanded greatly. We can modify the chemical structure of natural antibiotics to improve their therapeutic efficiency or reduce their side effects. In recent decades, compounds have been extracted from bacteria that are the source of some important anticancer chemotherapy drugs for cancer management. In this article, some of these drugs are discussed.

Abstract Antibacterial textiles impregnated with chitosan copolymer (OA-g-CSO) have shown good antimicrobial performance and are resistant to different strains by inhibiting the growth of bacteria. However, the partial performance of these antibacterial textiles against Gram-positive and Gram-negative strains has not been well evaluated. In this research, two types of OA-g-CSO copolymers with different precursor ratios were prepared, in which the minimum amount of amino substitution was considered to show antibacterial properties on textiles. The performance of these two types of copolymers on textiles was evaluated by examining the time effect of textiles impregnation with OA-g-CSO, the maximum retention time of the OA-g-CSO emulsion, and the detergent effect on the antibacterial textiles.

Abstract Solvent-free synthesis of saturated and monounsaturated wax esters (WEs), 3a-j with carbon chain ranging from C₂₆ to C₃₈ was successfully demonstrated through esterification of long chain fatty acids (LCFAs), 1a-g (C_10:0, C_12:0, C_16:0, C_18:0, C_18:1, C_18:1,12-OH, C_22:0, and C_22:1 acids) with long chain fatty alcohols (LCFAlc), 2a-d (cetyl (C₁₆), stearyl (C₁₈), behenyl (C₂₂) and erucyl (C_22:1) alcohols) by SO₃H-carbon catalyst derived from glycerol. The optimized reaction conditions for the efficient synthesis of WEs with excellent conversion and selectivity recorded in solvent free system are: 20 wt.% of SO₃H-carbon catalyst, reaction time of 6-10 h, temperature of 90 °C and substrate (LCFA:LCFAlc) molar ratio of 1:1. All the synthesized WEs were purified by silica gel column chromatography and characterized by FTIR, ¹H-NMR, and GC-MS spectral studies. In addition, this methodology involves simple workup protocol, without use of dean stark or dehydrating agents compared to the reported homogeneous/heterogeneous catalysed methods. Furthermore, the resulting synthetic WEs can play a potential alternates for the commercial products extracted from natural sources of lesser availability, thus making this SO₃H-carbon catalysed route very promising for further potential industrial implementation.

Abstract The nutritional value of honey depends on its chemical composition, which is influenced by the surrounding environment such as the botanical source and geographical origin. In a study, these twenty samples of honey were collected from various regions in Libya and analyzed to illustrate this variation. During our study, we discovered that all honey samples were contaminated with trace elements, which can be attributed to various factors such as the use of steel or galvanized containers in processing, shipping, or storage, exposure to insecticides, and human activity. As a result, the interpretation of the results may not be entirely reliable due to the presence of various unknown variables. Electrothermal atomic absorption spectrometry was utilized to analyze the tree trace elements Ni, Cd, and Pb. Furthermore, a statistical analysis was conducted to determine any existing correlation between the geographical origin and the variation in the presence of these elements from one sample to another. In addition, the pollen grains analysis of all honey samples was performed to identify the botanical source of each sample and interpret the variations in the nutritional value of the elements content from one sample to another. The ranges of the elements were as follows: Ni (0.20-0.75 mg/kg), Cd (0.250-1.75 mg/kg), and Pb (0.25-51.00 mg/kg).

Abstract The purpose of this study was to measure the total phenol and flavonoid content and assess the antioxidant and anti-thrombocyte activity in ethanol extracts of Cassia fistula seeds. Aluminum chloride was used to calculate the amount of flavonoids, and Folin-Ciocalteu reagent was used to calculate the total amount of phenolic compounds using a spectrophotometric method. The in vitro antioxidant activity of the analyzed extracts was evaluated utilizing the DPPH approach. The total phenolics and flavonoid contents in the seeds extract Cassia fistula 246 ± 0.08 mg GAE/g dw and 118 ± 0.001 mg QE/g dw, respectively. The obtained results concluded that it may be considered a good amount of phenolic and flavonoid compounds. The in vitro anti-inflammatory properties showed the highest percentage inhibition of protein denaturation was 54% for 45 µg/ml and 70% for the reference drug diclofenac sodium at a similar dose. The minimum inhibition of hemolysis 58% was observed at 50 µg/mL of Cassia fistula seeds extract and 81% for the same dose of standard aspirin. The results presented that the ethanol seeds extract of Cassia fistula has potential anti-thrombocyte activity. IC₅₀ values were used to express the antioxidant activity of the investigated extracts. The IC₅₀ values was found to be 8.90 µg/ml for ethanol seeds extract which is comparable to that of ascorbic acid (IC₅₀ = 6.73 µg/ml) a well-known standard antioxidant. Among these results, the lower the IC₅₀ showed the higher the free radical scavenging activity. Among these findings, the stronger the free radical scavenging activity was seen the lower the IC₅₀ indicated. Based on all of the findings, we concluded that the anti-thrombocyte antioxidant and anti-inflammatory activities may be caused by phytochemicals identified in C. fistula extract.

Abstract Polymer and chemical industries are actively concentrating on the discovery and application of vegetable oils for polymer composites. In this work, castor oil homopolymers and their copolymers with styrene were made, as well as their assessment was done by spectroscopic methodology, thermo gravimetric analysis (TGA), and gel permeation chromatographic (GPC) strategy. The ASTM standard approach was employed to determine these polymers' efficiency in base oil. Photo-micrographic imaging was utilized to assess the efficacy of additives as pour point depressants by examining their impact on the microstructure. The biodegradability experiment for polymers was also conducted and outcomes are quite promising. Their performance comparisons have been further assessed and reported.

Abstract Ranunculus arvensis L. is a medicinal herb traditionally used for various purposes. The objective of the present research project was to find an effective and green method for obtaining bioactive natural products from it. Aqueous glycerol was employed as a green extracting medium, and the bioactive compounds were estimated as total flavonoid content (TFC) total phenolic content (TPC), antioxidant activity, and metal chelating activity (MCA). Response surface methodology (RSM) was applied to optimize the extraction process with temperature, time, and solvent (glycerol) concentration as input factors. The optimized conditions were 30 °C, 30 min, and 70% glycerol concentration at which the responses were TPC 7.15 mg gallic acid equivalents/g DW (dry weight), TFC 14.8 mg rutin equivalents/g DW, antioxidant 59.55%, and MCA 49.14%. The model was strongly supported by the validation study. The explored extraction process for bioactive natural products from R. arvensis is predictably applicable. Hence, 70% aqueous glycerol at almost room temperature and a minimum duration of 30 min can allow optimum extraction of phenolics, flavonoids, antioxidants, and metal chelators from R. arvensis.