Enzyme immobilization is a powerful method to improve the stability, reuse, and enzymatic properties of enzymes. The immobilization of the α-amylase enzyme from Aspergillus fumigatus on a chitin-bentonite (CB) hybrid has been studied to improve its stability. Therefore, this study aims to obtain the higher stability of α-amylase enzyme to reduce industrial costs. The procedures were performed as follows: production, isolation, partial purification, immobilization, and characterization of the free and immobilized enzymes. The CB hybrid was synthesized by bentonite, chitin, and glutaraldehyde as a cross-linker. The free enzyme was immobilized onto CB hybrid using 0.1 M phosphate buffer pH 7.5. The free and immobilized enzymes were characterized by optimum temperature, Michaelis constant (K_M), maximum velocity , thermal inactivation rate constant (k_i), half-life (t_1/2), and transformation of free energy because of denaturation (ΔG_i). The free enzyme has optimum temperature of 55°C, K_M = 3.04 mg mL⁻¹ substrate, , k_i = 0.0171 min⁻¹, t_1/2 = 40.53 min, and ΔG_i = 104.47 kJ mole⁻¹. Meanwhile, the immobilized enzyme has optimum temperature of 60°C, K_M = 11.57 mg mL⁻¹ substrate, , k_i = 0.0045 min⁻¹, t_1/2 = 154.00 min, and ΔG_i = 108.17 kJ mole⁻¹. After sixth cycle of reuse, the residual activity of the immobilized enzyme was 38%. The improvement in the stability of α-amylase immobilized on the CB hybrid based on the increase in half-life was four times of the free enzyme.

Native to tropical Asia, Sesbania grandiflora (L.), Pers is a member of the Fabaceae family of flowering plants. All parts of S. grandiflora are used in traditional medicine and phytochemical investigations have been conducted on extracts of the leaves, seeds and roots of S. grandiflora to provide scientific validation of its properties. However, to date, no study has determined the phytochemical constituents of S. grandiflora stem bark. The stem bark powdered of S. grandiflora was extracted exhaustively with n-hexane, EtOAc and 90% aqueous MeOH sequentially. In this study, we successfully isolated two new 2-arylbenzofurans, sesbagrandiflorain A and B, from the EtOAc stem bark of S. grandiflora. The structure elucidation of these compounds was determined by using one- and two-dimensional nuclear magnetic resonance, ultraviolet and infrared spectroscopy and electrospray ionisation time-of-flight mass spectrometry. The finding expands the understanding of the natural constituents of the Fabaceae and, in particular, the Papilionoideae genera.

Oriental Journal of Chemistry is a peer reviewed quarterly research journal of pure and applied chemistry. It publishes standard research papers in almost all thrust areas of current chemistry of academic and commercial importance. It provides a platform for rapid publication of quality research papers, reviews and chemistry letters. Oriental Journal of Chemistry is abstracted and indexed in almost all reputed National and International agencies.

Artonin E was isolated from the root bark of A. rigida. The isolated compound was then esterified using a known procedure by the addition of acetic anhydride with pyridine catalyst. The structure of the synthesized compound was carefully determined by physical and spectroscopic techniques and compared to the data in the literature. The anticancer activity test against murine leukemia cancer cells P-388 showed that the ester compound has good activity with an IC50 of 2.79 μg/mL and much better stability during storage compared to Artonin E itself.