Mosquitoes represent the deadliest animal species in tropical regions because they can affect human health. Personal protection which is mosquito repellent has been used since 20th century. Mosquito repellent which contains plant-based ingredients has high demand from consumers since its efficacy is as good as synthetic ones. Citronella genus plants are originally extracted to be used in perfumery, then they were used for ingredients of plant-based mosquito repellents as they have repellent properties. Citronellalbased repellent has an effective dose such as N,N-diethyl-meta-toluamide dose. However, the oil content has high volatility causing it to reduce its efficacy because the oil evaporates. Recently, the structure of citronellal compound has been modified into hydroxycitronellal by adding some functional groups to reduce the release rate, prolong the protection time and improve the stability of the compound. The release rate properties are affected by functional groups and the molar mass of the compounds. This paper presents a summary of recent catalyst and solvent usage during synthesis, characterization and comparison of mosquito repellents.

Exposed to the pollution has led to generation of reactive oxygen species (ROS) in human skin. ROS generated cause many skin diseases such as skin-aging, inflammation, melanogenesis and skin cancer. ROS is a family of oxygen-based free radicals that contains or capable of producing an unpaired electron. Antioxidant is a molecule that can inhibit the reaction of free radical from ROS by donating its electron. Averrhoa bilimbi Linn. (AVBL) is one of the potent natural antioxidant belongs to the group of Oxalidaceae which can be widely found in Asia including Malaysia. Traditionally, this plant has been used to treat many diseases such as cough, itchiness, pimple, fever and inflammation. As a result, much attention has been directed towards the studies regarding the potential of this plant in treating disease. The present study was undertaken to assess the antioxidant activity of AVBL leaves extract. The AVBL leaves were extracted using sonicator with ethanol and distilled water as two different types of solvent. The total phenolic content (TPC) and flavonoid content (TFC) of this study were determined by using Folin-Ciocalteu reagent and aluminium chloride colometric assay. Antioxidant activity of the plant extract was tested using 2,2- diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing power (FRAP). From the analyses, water extract of AVBL possessed greater extraction yield (11.231%) as compared to ethanolic extract (5.358 %). However, ethanolic extract of AVBL leaves revealed higher result of TPC (126.4±0.35 mg/g gallic acid equivalent), TFC (32.80±0.37 mg/g quercetin equivalent), DPPH (0.0019±0.0003) and FRAP (41.81±0.45 mg/g gallic acid equivalent). The results of TPC and TFC have strongly positive correlation with antioxidant capacity (r = 1). Thus, it can be concluded that this plant is a potent source of natural antioxidant.

Exposed to the pollution has led to generation of reactive oxygen species (ROS) in human skin. ROS generated cause many skin diseases such as skin-aging, melanogenesis and skin cancer. ROS is a family of free radicals based on oxygen that contains or may generate an unpaired electron. Antioxidant is a molecule that can inhibit the reaction of free radical from ROS by donating its electron. Averrhoa bilimbi Linn. (AVBL) is one of the potent natural antioxidant belongs to the group of Oxalidiaceae which can be widely found in Asia including Malaysia. Traditionally, this plant has been used to treat many diseases such as cough, pimple, fever and inflammation. As a result, much attention has been directed towards the studies regarding the potential of this plant in treating disease. The present study was undertaken to assess the antioxidant activity of AVBL leaves extract. The AVBL leaves were extracted using sonicator with ethanol and distilled water as a solvent. The total phenolic (TPC) and flavonoid content (TFC) of this study were determined by using Folin-Ciocalteu reagent and aluminium chloride colometric assay. Antioxidant activity of the plant extract was tested using 2,2- diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing power (FRAP). From the analyses, water extract of AVBL possessed greater extraction yield (11.231%) as compared to ethanolic extract (5.358%). However, ethanolic extract of AVBL leaves revealed higher result of TPC (126.4±0.35 mg/g gallic acid equivalent), TFC (32.80±0.37 mg/g quercetin equivalent), DPPH (0.0019±0.0003 g/mL) and FRAP (41.81±0.45 mg/g gallic acid equivalent). The results of TPC and TFC have strongly positive correlation with antioxidant capacity (r = 1). Thus, it can be concluded that this plant is a potent source of natural antioxidant.

Cymbopogon nardus (C. nardus) or fragrance lemongrass is a member of Gramineae family which is well known for its citronella oil content that is commonly used as a natural fragrant oil, in insect repellents, as well as in beauty, household and perfumery products. C. nardus is one of the unique herbs that has been widely discussed in Malay Medical Manuscript and has been consumed by Malay practitioner as it possesses various anti biological activities such as anti fungal, anti bacteria and anti-inflammatory. In traditional system of medicine among Malay traditional people, C. nardus has been used for the treatment of fever, muscle pain, and many kinds of illness. Various uses shown by this herb and the tendency of high application of the herb among Malay society has led us to study C. nardus according to the scientific perspective. Therefore, the objectives of this study are to identify the morphology of C. nardus and its application from Malay traditional’s perspectives, as well as to determine the active compounds present in the herb through scientific findings. Two different parts of leaves and stems of C. nardus were extracted using steam distillation method for 2 hours. The chemical composition of citronella oil was determined by Gas Chromatography-Mass Spectrometry (GC-MS). An amount of 0.55 % and 0.024 % of citronella oil were extracted from leaves and stems parts, respectively. The main compositions of oil extracted from the leaves part are citronellol (41.4 %), methyleugenol (80.2 %), citronellal (39.7 %), D- limonene (40 %) and geraniol (36.5 %). Meanwhile, the extraction from the stems composed of α-Himachalene (45.34%), Citronellol acetate (48.2 %), cis-Geraniol (57.8 %) and endo- Borneol (26.2 %). Thus, it can be concluded that C. nardus leaves extraction yield higher citronella oil content as compared to stems and consist of different main chemical compositions between the two parts.

Coumarin consists of a natural compounds group, which is found in different plants. Those Coumadin's, which are secluded from the plant, displayed that their compounds had a pasmolytic and hypotensive state, which has a vital role in plant biochemistry and physiology, by acting not only as antioxidants and enzyme inhibitors but as a precursor of toxic elements as well. Furthermore, these compounds have an essential role to play as plant growth hormones, growth regulators, respiratory control, and photosynthesis and as a defence mechanism against any kind of disease. They also play a role at various levels of cancer development since some of them have cytostatic characteristics, while others have cytotoxic effects on the organism. Thus shown, that the ancient correlation of plant coumarins with different animal and other species during evolution is the reason for the extensive spectrum in biochemical and pharmacological effects of these chemicals in biological arrangements. Metalo proteins, which are the hub of enzymatic process, which display an important role in biological arrangements. They discover the structure of active locations and play their part as biological redox assisters. Various cases proved that metal complexes of coumarin exhibited increased biological activities as compared to their ligands. As a result of their half-filled orbitals, transition metal display different oxidation states, and a diversity of coordination structures and ligand spheres.

Considerable interest has been aroused for copper complexes of coumarins due to their wide variety of biological activity. Three copper complexes of coumarin; A1, A2 and A3 were synthesized and evaluated for antitumor activity by using MTT assay. These complexes show antitumor activity against breast cancer MCF7 with IC values of 1.87, 1.87 and 30?g/ml respectively and exhibit 50 antitumor activity against lung cancer A549 with IC50 values of 7.5, 15 and 1.87?g/ml respectively.

Kemasukan pelajar ke institusi pengajian tinggi seluruh negara kini direkodkan mengalami kemerosotan. Di Pusat Tamhidi USIM, pendaftaran pelajar berkurang sebanyak 21.3% berbanding bilangan pelajar tahun lalu. Melalui soal selidik (kuantitatif) yang dijalankan ke atas 583 orang pelajar ambilan baharu sesi 2022/2023, jumlah pelajar yang memasuki Tamhidi adalah 50.3% berasal daripada aliran sains, namun dalam Rajah 1 hanya 46.7% (23.2+23.5) daripada responden yang berada di Tamhidi Perubatan, Pergigian dan Sains (TPPS) dan Tamhidi Sains Fizikal dan Teknologi (TSFT). Segelintir (3.6%) pelajar daripada aliran sains memilih untuk bertukar aliran ke Tamhidi Syariah dan Undang-Undang (TSU). Pelajar lepasan SPM yang berumur 18 tahun terdorong untuk memilih program di Pusat Tamhidi atas faktor dorongan keluarga dan cadangan daripada guru dan kaunselor sekolah. Kedudukan kewangan keluarga juga merupakan faktor yang agak memainkan peranan daripada segi pendaftaran pelajar, memandangkan terdapat beberapa orang pelajar yang tidak mendaftar sejurus menerima tawaran yang berkemungkinan disebabkan faktor kewangan. Adalah diharapkan bilangan kemasukan pelajar ke Pusat Tamhidi akan meningkat pada tahun-tahun akan datang dan seterusnya USIM dapat melahirkan pelajar-pelajar yang berdaya saing dan holistik pada masa hadapan.

The use of mobile technology such as smartphones, allows the teaching and learning process to use synchronous communication methods, integrated with face-to-face collaborative learning methods. This study aims to improve communication between students-lecturers and students-students in and outside of the classroom besides improving student-centered learning in the tutorial sessions for Hydrocarbon Chemistry courses. The three main objectives of the study are to increase student’s engagement during the tutorial sessions, helping students to improve motivation and self-confidence to answer all the tutorial questions correctly as well as improving student’s achievement. A total of two cycles of action research have been carried out involving 65 First Year students of Industrial Chemistry Technology Program (TKI), Faculty of Science and Technology, USIM.. Three instruments were used to analyze the findings of the study which are pre and post-test, structured observation and questionnaire. The results showed that, there was a slight increase in the average percentage of student achievement after intervention. The result of the observation was that the students became more confident in answering questions and the involvement of students in the classroom increased. Key Words: Synchronous communication; collaborative learning; student’s engagement; higher education; Telegram

This research aims to evaluate the level of scientific research output concerning Siwak or Miswak using Scopus during the period 2014 to 2024 by employing bibliometrics indicators such as articles, types of documents in this field of research, contributions among different countries, institutions wise contribution, preference of journals for communication this research area. A thorough examination was undertaken on 245 English records sourced from Scopus databases to yield insights. The results highlight a notable escalation in the annual publication of scientific research across the globe. Saudi Arabia (179), and Egypt (107) emerged as the leading contributors on the list India (85) occupies the third rank in global countries’ production over time. The most relevant sources by research for siwak or miswak title were the Molecules with a count of 6 (3.31%). In addition to this, the graphical mapping of data is represented by VOS Viewer and Biblioshinybibliometric mapping software for a better understanding.

Series of heterogeneous catalyst were synthesized by the direct immobilization of various concentrations of MoO2(acac)2 and VO(acac)2 on montmorillonite (MMT) K10 clay. The immobilized catalysts were characterized by x-ray powder diffraction (XRD), atomic absorption spectroscopy (AAS), thermal gravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) with KBr pellet method. The basal spacing for Mo-MMT K10 and V-MMT K10 obtained from XRD analysis suggests that the clay structure were retained. AAS analysis revealed that as the concentration of the metal increased, the elemental compositions of Mo and V complexes on MMT-K10 samples were also increased. The bands that appear in the region of 1300-400 cm-1 from FTIR are attributed to the stretching vibration from SiO2 tetrahedra, indicating the structure of the clay. Besides from the thermal analysis, the higher concentration of metal complexes (Mo and V) immobilized on MMT-K10 structure make them being better hydrophobic nature thus lower the loss of physisorbed water molecules weakly bound to the material.

6-hydroxy-4metheyl-5-phenyl azo coumarin have been prepared and characterized by elemental analysis, infrared (IR), proton nuclear magnetic resonance (1H NMR) and Mass spectra. The important infrared (IR) spectral bands corresponding to the active groups in the ligand and the solid complexes under investigation were studied. Also the important fragments in the ligand and the complexes were done using mass spectra and the main peaks were corresponding to the molecular weights of the ligand and complexes. The solid complexes have been synthesized and studied by elemental and as well as by IR, 1H NMR, mass spectra, molar conductance,. All of the prepared solid complexes behave as non-electrolytes in chloroform.

Perfumes and fragrances are seen as an essential part of life in many countries, and many men and women use perfumes regularly. Originally, the perfume ingredients were derived from natural sources such as essential oils. However, these natural ingredientsencountered challenges, such as poor crop quality, a limited supply of supplies, or difficulties using plant or animal extracts. Hence, with the development of synthetic organic chemistry in the 19th century, many ingredients were produced synthetically, resulting from the creativity of laboratory chemists, and used in today’s perfumes. Acetal is one of the synthetic aromatic chemicals used as ingredients in perfume nowadays. This paper reviewfocuses on synthesis and characterization techniques for analyzing acetal derivatives of 2-methyl-3-(4-R-phenyl)propanal and their perfumery application, such as odor characteristics.