No abstract

A new phenolic sesquiterpene, dysoxyphenol (1), and the known sesquiterpene, 7R,10S-2-hydroxycalamenene (2), were isolated from the acetone extract of Dysoxylum densiflorum seeds. The structures of these compounds were determined based on physical, Nuclear Magnetic Resonance, and mass spectral data. Both compounds were evaluated for their antibacterial and antifungal properties against seven pathogenic bacteria and two wood-rotting fungi, respectively. The results showed that both compounds have significant antibacterial properties only against Bacillus subtilis (Minimum Inhibitory Concentration 28 μM), while in the antifungal evaluation compound 1 was found to be more active than compound 2. Therefore, compound 1 has promising antifungal properties that can be developed further for finding new antifungal agents.

Quantitative structure–activity relationship (QSAR) and molecular docking approach were carried out to design novel anti-tuberculosis agents based on xanthone derivatives. QSAR designed new compounds were calculated by Austin Model 1 (AM1) methods and analysis of multi-linear regression (MLR). The result showed that the best model as follows: Log IC50 = 3.113 + 11.627 qC1 + 15.955 qC4 + 11.702 qC9, this result has appropriate some statistical parameters (PRESS = 2.11, r2 = 0.730, SEE = 0. 3545, R = 0.6827, FCal/FTab = 4.68), and being used to design a potential anti-tuberculosis drugs with substituted amide, sulfoxide, and carboxylate group xanthone scaffold by a number of their inhibitory concentration (IC50). The mechanism action of sulfonamide substituted on the xanthone scaffold as anti-tuberculosis was carried out using molecular docking. Docking inhibition studies were carried out on MTB C171Q receptor (4C6X.pdb) as KasA inhibitors using by the discovery studio. Based on the binding interaction showed, the sulfonamide substituted xanthone has potential being the anti-tuberculosis drugs by KasA inhibitor for target drug activity.

Covid-19 has caused more than 14 million confirmed cases and more than 6 hundred deaths as of 21 July 2020 globally. However, there is no approved drug to treat the disease. Xanthone is a potential therapeutic option for the virus that have been tested using molecular docking. There were 12 of xanthone compounds and its derivatives which have been docked against two protein crystals, 2GX4.pdb and 6FV1.pdb, which obtained two potential compounds of hydroxyxanthone derivatives with sulfonate and chloro substitution. These compounds are potentially developed into one of the agents for the treatment of infection COVID-19 disease. Based on energy data and interactions with amino acid residues when compared with its own native ligands, namely NOL and E8E, respectively. Energy docking and energy docking interactions are equal to - 43.3057and - 45.5805 Kcal/mol respectively, during interactions with amino acid residues in the form of Gly 142, His 163, Cys144, Glu166, Gln164 and His 41. Based on these two data, it can be concluded that trihydroxyxanthone compounds 4 and 8 with chloro and sulfonate substitution are very potential to be developed as drug agents for Covid-19 disease therapy through protease inhibition.

Alginate-chitosan based biopolymer for possible application as edible film coating has been studied. Alginate hydrosol and chitosan hydrosol with mass ratio of 1:1 were mixed to form a thin membrane and then dried. The obtained alginate-chitosan membrane was confirmed using FTIR spectrophotometers. Characterization of the membrane, which includes thickness, tensile strength, water vapor sorption, resistance to pH change and antimicrobials properties, were conducted. It was showed that the interaction of alginate and chitosan in the membrane occurred through the electrostatic interaction of the carboxylic group of alginate and ammonium groups of chitosan. At the same thickness, the alginate-chitosan membrane tensile strength was higher and more resistant to pH changes than both native alginate and chitosan membranes. Furthermore, the alginate-chitosan membrane has good antibacterial potential against gram-positive bacteria (Staphylococcus aureus) and gram-negative bacteria (Escherichia coli). It is expected that the alginate-chitosan membrane has the potential application for safe and efficient fruit coating.