Band 9, Heft 6

The emerging phase of bioeconomy demands that human beings be concerned more with ecofriendly practices in every aspect of life. Thus, the demand for biopolymer/biopolymer-based composite materials has witnessed a surge in recent decades. Biopolymeric composites at macro, micro, and nano scales have various applications in environmental cleanup. Biopolymers from natural resources have established an important position owing to their easy availability, abundance, and biodegradability. This review reveals the advantages of biopolymer usage in the field of environmental remediation over conventional practices and also the advantages of biopolymer composites over general biopolymeric material. Further, it focuses on the recent rapid development of nanotechnology, which has led to significant advances in the design and synthesis of biopolymer-based nanocomposites, with higher specific surface areas that can be functionalized to strongly adsorb contaminants in comparison with conventional adsorbents. It also presents the biopolymer-based composite materials separated on the basis of scale commonly used for environmental applications such as the removal of dyes, oil–water separation, and air filtration. This review also summarizes the benefits and drawbacks on biopolymer composite usage along with future perspectives to give an idea on the areas for researchers to focus on in the future.

Green vegetables are examples of staple plants eating in Nigeria, and are assumed to be a well-off basis of phytochemicals and amino acids that are useful for the management and prevention of infections. However, in the farming of these vegetables, glyphosate-based herbicides (GBH (round up™)) are used as control against pests invasions which has cause reasons to be concern about their effects on the phyto-constituents present in these vegetables. In this study, we evaluated the phytochemicals constituents and amino acid profile of the leaves of Telfairia occidentalis Hook F, Amaranthus viridis Linn, Celosia argentea Linn and Cnidoscolus aconitifolius (Mill.) I. M. Johnst popular edible vegetables in Southwestern Nigeria. The vegetables seeds of these plants mentioned above were acquired from Institute of Agricultural Research and Training (IAR&T) Ibadan. And on a land designed and previously treated with a GBH (round up™) the seeds were planted and allowed to grow. A destructive method of leaves after maturation was achieved by out rightly plucking them out and air-drying under shade. Phytochemical assessments were done on milled plant samples to determine the presence of ten phyto-constituents. Centrifugation of powdered samples (2 g each) with acetonitrile at 1000 rotations per minute’s (rpm) was used to extract amino acids. Thereafter the extracts were individually spotted on a thin layer chromatography (TLC) plate and developed using the mobile phase consisting of methanol: acetic acid: water in ratio 7:2:1 v/v. The visualization for the presence of amino acids was completed by spraying the developed chromatographic plates with 0.5% ninhydrin in 2-propanol solution and observed in both day light and under the ultraviolet lamp and the retention factor ( R f ).calculated for the different spots developed to determine the type of amino acids present. The assessment of phytochemicals from the four vegetables reveals the presence of alkaloids, tannins and steroids in all samples while anthraquinone glycosides, terpenoids and cardiac glycosides were absent and other phytochemicals varying in them. Ssaponins was found absent in Telfairia occidentalis and flavonoids in Cnidoscolus aconitifolius respectively. The observation of the TLC plates in daylight shows that the vegetables likely contained primary, secondary and proline amino acids while the calculation of the R f values of the TLC spots observed under an ultraviolet (UV) light indicated that amino acids found in the vegetables were methionine, tyrosine, leucine, isoleucine. However, phenylalanine was found only in Celosia argentea . The study evaluated phytochemicals and amino acids parameters in four leafy vegetables grown on contaminated glyphosate based herbicide soil and assessments shows that their medicinal properties were not altered with the minimal exposure to contaminant.

This paper presents successful resynthesizing of several dibutyl-, diphenyl-, and triphenyltin(IV) carboxylate compounds, and their activity against leukemia cancer cell, L-1210. The compounds were synthesized by reacting the dibutyltin(IV) oxide (DBTO) ( 1 ), diphenyltin(IV) oxide (DPTO) ( 3 ), and triphenyltin(IV) hydroxide (TPTOH) ( 5 ) with 3-hydroxybenzoic acid (3-HHBz). Prior to cancer activity tests, the compounds were characterized by UV–Vis, FT-IR, NMR (both 1 H NMR and 13 C NMR), and microanalysis to determine elemental composition of the samples. The anticancer tests revealed that triphenyltin(IV) 3-hydroxybenzoate (TPTHBz) ( 6 ) displayed significantly higher activity than those exhibited by dibutyltin(IV) di(3-hydroxybenzoate) (DBTHBz) ( 2 ) and diphenyltin(IV) di(3-hydroxybenzoate) (DPTHBz) ( 4 ).

Analogies are frequently used in chemistry education (and science education in general), above all when introducing a new concept or when a concept is perceived as too abstract by the teacher or by the learners. On the one hand, analogies can offer functioning opportunities for clarifications; on the other hand, they may risk engendering misinterpretations or misconceptions, because the terms of a given analogy may be perceived differently by the teacher and by the student, or may be too farfetched to have a clarifying role. In order to maximize the benefits and minimize the risks, the design of analogies needs to entail careful attention both to the nature of the analogy and to its ‘matching’ to the nature of the concept to which it refers. This involves vigilant analysis of all the details and of their implications, and the parallel design of a viable way to guide the student through the terms of the analogy; such guidance is actually meant to become an explanation component. The paper considers concrete examples from the author’s direct experience with general chemistry and physical chemistry courses, and analyses both the design of the details of the selected analogies and the corresponding guidance pathways. It also discusses related issues like the importance of limiting the resort to analogies to the cases where they can actually have a significant impact on students’ understanding, and the opportunity of replacing them with molecular models whenever feasible, as a model’s nature is closer to the mental images that it is desirable to promote through students’ perceptions. Comparisons of the types of guidance needed for analogies, for general-type visualization, and for visualization through models are also included. The take-home message reiterates the considerations on the nature of analogies as something to be designed, on the teacher’s active role in the design, and on the possibility of including students in the design process, when the concepts and corresponding analogies are suitable for such inclusion.

The introduction of computation chemistry has increased in the undergraduate chemistry curriculum. Our method of instruction is centred on an online, self-paced approach where students interact with the material through an instructional handbook, videos, and assignments. In our inorganic undergraduate curriculum students explore computational chemistry though optimization of organometallic complexes, modelling the infrared (IR) and nuclear magnetic resonance (NMR) spectra and investigation of the shape and energy of molecular orbitals. These results are compared to experimentally determined data. The effectiveness of introducing students to computational chemistry to characterize organometallic compounds will be highlighted.

Phytochemical constituents are important in the determination of plant activities. Their presence in medicinal plants gives their therapeutic values. These phytoconstituents possesses pharmacological activities that include antimicrobial, antioxidant, anti-inflammatory, analgesics, anti-diabetic, anti-hypertensive, antidiarrheal and several other activities. These activities can be determined by the identification of the phytochemicals present in medicinal plants. Petivera alliaceae L. is one of the medicinal plants in the family of phtytolaccaceae used traditionally as an antirheumatic, analgesics, antimicrobial, anticancer and immunomodulators. It is believed to possess rich phytoconstituents especially sulphur containing a broad-spectrum antimicrobial activity. Although the root extracts is been explored but there are limited publication to its root fractions. Therefore, the study is aimed at screening phytochemicals present in the fractions and volatile oil of the root parts of P. alliaceae using qualitative tests and Gas Chromatography–Mass Spectrometry (GC–MS) analysis. Fresh root parts of Petivera allliaceae plant were collected and air-dried. The dried root parts was macerated in absolute methanol for 72 h. The solution was extracted and dried. The dried root methanol extract was partitioned into n -hexane (PAH) and methanol fractions (PAM), while volatile oil (PAO) was extracted using Clevenger-type hydrodistillation method. The result shows that alkaloids, saponins and flavonoids were present while cardiac glycosides, phenol, terpenoids and anthraqunione glycosides were absent in both fractions. The GC–MS analysis identified 18 compounds in PAH, 19 compounds in PAM and 28 compounds in PAO. The fractions and volatile oils of P. alliaceae roots are rich in phytochemical constituents and compounds should be isolated from the fractions and explored for their potentials.

The growing consciousness about global environmental concerns, particularly landfills, in conjunction with the rapid use of petroleum-based plastics, is a key factor behind the use of natural and biodegradable polymers in short-life applications like food packaging, container, and tray. Sugar palm stem is a biomass that has proven the potential to produce biodegradable polymers such as sugar palm starch. Nevertheless, their applications were limited due to their low tensile strength and excessive hydrophilicity. Plasticization using polyols, reinforcement with sugar palm fiber, cellulose, microcrystalline cellulose, or nanocellulose, blending with thermoplastic polymer, and addition of essential oils has been used to maximize the functional qualities of the starch biopolymer. As the content of plasticizers grew, the glass transition temperature and water absorption ability decreased. Furthermore, the addition of sugar palm nanocellulose to sugar palm starch improves the performances of sugar palm starch-based films as a packaging material. Addition of essential oil contributes to antibacterial properties and slightly improved tensile strength of the film. A comprehensive understanding on the interaction of starch-based biodegradable polymer and nanocellulose constituents for enhancing the physico-chemical properties of starch-based films is prerequisite for researchers in the design of industrial products with enhanced functional attributes. To address the knowledge gap, more studies including the reinforcement of new types of biodegradable polymer and nanocellulose derived from natural sources should be conducted in order to continually populate the database for research purposes.

The most harmful to biological compounds is ultraviolet radiation (UVR) from the sun. UVC rays (100–280 nm) are extremely harmful to the skin. Fortunately, it is primarily absorbed in the earth’s troposphere by molecular oxygen and ozone. Although UVB (290–320 nm) accounts for only about 5 % of terrestrial UVR, its effects are typically much stronger than those of UVA (320–400 nm). UVR’s clinical effects on normal-appearing human skin can include erythema, pigmentation, suppression of acquired immunity and enhancement of innate immunity, all caused by UVB, and blood pressure reduction caused by UVA. Long-term effects include photocarcinogenesis and photoaging. All of these effects are supported by molecular or cellular effects such as DNA damage, ROS generation, melanogenesis, and the expression of numerous genes and related proteins. The use of sunscreen and avoiding prolonged sun exposure are the first lines of defense in photoprotection. Sunscreens with the appropriate SPF and protection spectrum are now the mainstay of many studies on UV damage. A variety of novel strategies for developing better sunscreens have been proposed. It has been proposed that incorporating antioxidant phenolic extracts into sunscreens can provide additional photoprotective qualities and provide greater protection by replenishing the skin’s natural reservoirs. Thus, the goal of this study was to look into the use of antioxidant extracts from medicinal plants in sunscreens and cosmetic formulations to boost photoprotection, with a particular emphasis on green extraction of these antioxidants from their complex matrices.

Enzyme catalysis and photocatalysis are two research areas that have become of major interest in organic synthesis. This is mainly because both represent attractive strategies for making chemical synthesis more efficient and sustainable. Because enzyme catalysis offers several inherent advantages, such as high substrate specificity, regio-, and stereoselectivity, and activity under environmentally benign reaction conditions, biocatalysts are increasingly being adopted by the pharmaceutical and chemical industries. In addition, photocatalysis has proven to be a powerful approach for accessing unique reactivities upon light irradiation and performing reactions with an extended substrate range under milder conditions compared to light-independent alternatives. It is therefore not surprising that bio- and photocatalytic approaches are now often combined to exploit the exquisite selectivity of enzymes and the unique chemical transformations accessible to photocatalysis. In this chapter, we provide an overview of the wide variety of light-driven bioprocesses, ranging from photochemical delivery of reducing equivalents to redox enzymes, photochemical cofactor regeneration, to direct photoactivation of enzymes. We also highlight the possibility of catalyzing non-natural reactions via photoinduced enzyme promiscuity and the combination of photo- and biocatalytic reactions used to create new synthetic methodologies.

The research on metallic clusters in relevance to its far-reaching involvement in the high technology sector, solid-state physics and catalysis is an interesting and significant field of study. In this report, the investigation of arsenic doped iron cluster, AsFe n ( n  = 1–4) aided by conceptual density functional theory (CDFT) method has been performed. CDFT based global descriptors-mainly HOMO–LUMO energy gap and other parameters of these clusters are worked out. Obtained data shows that band energy gap varies in the magnitude of 1.451–3.138 eV. Uppermost magnitude of HOMO–LUMO energy gap i.e. 3.138 eV is observed for AsFe while AsFe 4 show the smallest energy gap. It is noted that band gap of these systems decreases with increase in the cluster size, ‘ n ’. Direct association concerning both parameters HOMO–LUMO energy gap and molecular hardness of AsFe n clusters have been found. It indicates that among the studied compound AsFe is the most stable system whereas AsFe 4 is the least stable. Dipole moment of the clusters is observed in the variation of 2.303 Debye to 3.853 Debye, signifying that the bond within the clusters is ionic in nature. The computed bond length between Fe–Fe in AsFe n is in agreement with the experimental data.