Journal of the Chilean Chemical Society

EXPLORING ALIEN PLANTS AS A SOURCE OF BIOACTIVE MOLECULES

Mon, 21 Sep 2026 00:00:00 +0000

This study investigates the biological activity of leaf extracts obtained from two allochthonous plant species, Ailanthus altissima and Albizia julibrissin, selected for their invasiveness, for their use in traditional medicine and their distinctive biological interaction with the surroundings.

Experimental methodology included preparation of extracts by Soxhlet extraction, followed by biological analysis to assess antibacterial, cytotoxic and antiproliferative activities on cancer cell line and evaluation of antioxidant properties. Specifically, the potential antibacterial activity was evaluated determining the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). Cytotoxic and antiproliferative effects were examined using the MTT assay on the human breast cancer cell line MDA-MB-231 and the non-tumorigenic epithelial cell line MCF-10A. DPPH and ABTS assays were used to evaluate antioxidant activity in vitro, while intracellular ROS were quantified in SH-SY5Y cells to determine antioxidant capacity at the cellular level. Finally, total polyphenols were determined by the Folin-Ciocalteu assay and CG-MS analysis was performed to chemically characterize the extracts found to be the most active.

The results indicate that acetone extract of A. altissima exhibits bacteriotoxic activity on Bacillus cereus and antiproliferative as well as significant cytotoxic and antiproliferative effects on MDA-MB-231. In addition, acetone extract of A. altissima and A. julibrissin showed marked antioxidant activity in vitro and a cellular protection against oxidative stress in SH-SY5Y cells.

Overall, these findings highlight the potential of these plant extracts as sources of bioactive compounds for the development of therapeutic strategies targeting oxidative stress-related disorders.

NANOEMULSION OF DYSPHANIA AMBROSIOIDES ESSENTIAL OIL FOR THE CONTROL OF HOUSEFLY (MUSCA DOMESTICA L.)

Tue, 22 Sep 2026 00:00:00 +0000

The essential oil of paico (Dysphania ambrosioides Mosyakin and Clemonts, 2002) is renowned worldwide for its medicinal properties and its effectiveness in controlling pests and diseases. One of the most widely used methods of controlling Musca domestica L. (Diptera: Muscidae), a pest of medical, agricultural, and urban importance, is the use of synthetic insecticides. However, their extensive use has negative consequences, including pollution, harm to human health, and the development of resistance. The latter is a particularly prevalent problem in M. domestica, with over 80 cases of insecticide resistance worldwide to organophosphates, pyrethroids, and neonicotinoids. Given the need for alternative methods to control M. domestica, this study aimed to evaluate the fumigant activity of pure and formulated D. ambrosioides essential oil against adult M. domestica, as well as the stability of these formulations over time. Both pure and formulated essential oils exhibited high fumigant activity at concentrations below 5 µL L^-1 of air. Formulation A exhibited the most significant toxicity after 24 hours (LC₅₀ = 2.89 µL L^-1 air), had an average droplet size of less than 20 nm, and remained stable for over 14 days. These results suggest that D. ambrosioides essential oil can be used at low concentrations to control M. domestica, and that formulating it as a nanoemulsion increases its insecticidal activity.

ELECTROCHEMICAL QUANTIFICATION OF IBUPROFEN IN COATED TABLETS USING BUCKYPAPER-BASED MULTI-WALLED CARBON NANOTUBE-MODIFIED ELECTRODES

MOSCOSO RAUL, ALEJANDRO CHARMELL, JUAN A. SQUELLA — Tue, 22 Sep 2026 00:00:00 +0000

Illicit and unregulated pharmaceutical trade poses a growing public-health risk, particularly for widely self-medicated non-steroidal anti-inflammatory drugs such as ibuprofen (IBU). Here, we report a portable electroanalytical approach for the quantification of IBU in marketed coated tablets using buckypaper (BP)-based multi-walled carbon nanotube (MWCNT) electrodes. A BP-MWCNT sheet was transferred by a simple stamping procedure onto two transducers: a glassy carbon electrode (GC/BP) for differential pulse voltammetry (DPV) and a screen-printed electrode (SPE/BP) coupled to batch injection analysis (BIA) for amperometric, high-throughput screening. IBU exhibited an irreversible anodic response on BP-modified electrodes, with a pH-dependent peak potential enabling estimation of an operational interfacial pKa (~5.0) from Ep–pH trends. Quantification was linear from 0.3 to 1.0 mM. GC/BP–DPV delivered LOD/LOQ of 0.041/0.123 mM, while SPE/BP–BIA improved sensitivity (LOD/LOQ 0.022/0.066 mM) under hydrodynamic conditions using 10 µL injections. Accuracy was verified in commercial tablets, yielding recoveries near 100% (e.g., 103.2% for GC/BP and 100.2% for SPE/BP by external calibration) with low coefficients of variation. Application to unregulated street-market samples distinguished compliant tablets (~99%) from a substandard batch (~79%), below pharmacopeial limits (90–110%). Overall, the proposed BP-MWCNT workflow is positioned as a practical point-of-sale tool for shelf-level post-market monitoring in regulated retail, while also enabling rapid screening of tablets obtained from informal outlets.

EXPLORING THE USE FORESTRY BY-PRODUCTS IN RUBBER TECHNOLOGY: EFFECT ON THE MECHANICAL AND BIOLOGICAL PROPERTIES OF PINUS RADIATA SAWDUST ON NATURAL RUBBER-BASED COMPOSITES

Tue, 22 Sep 2026 11:52:32 +0000

Natural rubber (NR) is an essential material due to its diverse properties and applications. Although combining it with synthetic fillers improves the mechanical and physical properties of the compounds, the use of these synthetic reinforcements causes environmental problems due to their toxicity, high carbon footprint (CF), and low microbial susceptibility. This study aims to produce bio-based NR compounds using wood flour (WF, 150-300 μm), a byproduct of the forest industry, as a renewable filler. The effect of different WF contents (in phr) on the physical and mechanical properties of the compounds was investigated. A life cycle assessment (LCA) revealed that incorporating WF significantly reduces environmental impact. The carbon footprint decreases monotonically with increasing WF content, showing a clear dose-response relationship. Without considering biogenic carbon, the reduction is up to 25%. When biogenic carbon storage is included, the relative CF reduction reaches 132.4% for the 80 phr compound compared to the baseline (0 phr). Additionally, polyethylene glycol (PEG) into compounds with high WF content (80 phr) improved their resilience, water absorption, and max. elongation. Biodegradation tests with white rot fungi on compounds with 80 phr showed a maximum mass loss of only 2.29% after 50 days in vitro. Chemical and SEM characterization confirmed changes in chemical groups of wood, by degradation of lignin. NR and NR/WF composites showed signs of damage on surface microstructure. For instance, these biocomposites achieve certain resistance to fungal degradation even at high filler contents being promising for medium and long-term applications as a replacement for elastomers or synthetic foams. The results confirm that NR-WF compounds are promising and sustainable alternatives, combining improved hardness and elongation with a drastic reduction in carbon footprint and biodegradation potential.

CYCLOOXYGENASE-2 INHIBITORS AND ANTIOXIDANT COMPOUNDS IN BEE POLLEN IDENTIFIED USING HIGH-PERFORMANCE THIN-LAYER CHROMATOGRAPHY–EFFECT-DIRECTED ANALYSIS–MASS SPECTROMETRY

Tue, 22 Sep 2026 19:34:03 +0000

Bee pollen has recognized nutritional and functional properties. This study analyzed Brazilian bee pollens for antioxidant compounds and cyclooxygenase-2 (COX-2) inhibitors using high-performance thin-layer chromatography–effect-directed analysis (HPTLC–EDA) and tentative identification via mass spectrometry (MS). Distinct HPTLC profiles were observed for each sample, reflecting compositional differences. Antioxidant activity was demonstrated by DPPH radical scavenging in multiple zones, and two COX-2 inhibitory zones were detected in one sample by HPTLC–EDA. These bioactivities were linked to phenolic compounds and MS/MS analysis allowed the tentative identification of seven flavonoids (isorhamnetin-3-O-rutinoside, pinobanksin-5-methyl-ether-3-O-acetate, quercetin-3-methyl-ether, quercetin-3-O-glucoside, kaempferol-3-O-rutinoside, isorhamnetin-O-acetyl-rutinoside, and quercetin-dimethyl-ether). Notably, quercetin-3-methyl-ether exhibited both antioxidant and COX-2 inhibitory activity, which is particularly relevant due to the constant search for COX inhibitors with no harmful cardiovascular effects. Therefore, bee pollen is a relevant matrix containing compounds with antioxidant and anti-inflammatory potential. This is the first report of isorhamnetin-O-acetyl-rutinoside and quercetin-dimethyl-ether in bee pollen.

COMPUTATIONAL STUDY OF OXAZOLIDINOINDOLE-BASED CHROMOGENIC PROBES FOR Β-GALACTOSIDASE DETECTION

Juan Carlos Santos, Germán Barriga-González, Carlos Escobar — Tue, 22 Sep 2026 19:45:09 +0000

This study investigates phenoxystyrenyl-oxazolidino-indole (POI)-based chromogenic probes for β-galactosidase detection from a computational perspective. The POI probe undergoes a pronounced UV–vis color change (from colorless to red) upon interaction with β-galactosidase, leading to the formation of a hydroxyethylindolium zwitterion. To elucidate the electronic processes behind this color change, we introduced -H, -CN, and -OCH₃ substituents in the phenoxy moiety and analyzed their electronic properties using TD-DFT, NBO, ELF, and LOL methods. Our findings highlight the critical role of electron-withdrawing substituents in sensor response. The -CN group reduces electron delocalization, hindering the formation of the colored product, as confirmed by natural resonance theory (NRT), second-order perturbation, and topological analyses. Conversely, the -OCH₃ substituent enhances delocalization, preserving the chromogenic response. NBO second-order perturbation analysis reveals an electronic delocalization pattern extending from the phenoxy to the indole through the styrenyl moiety. Electron-donating groups stabilize resonance forms, while electron-withdrawing groups, like the cyano group, decrease the number of resonance forms. Absorption transitions in the 400-550 nm region explain the characteristic red color of the hydroxyethylindolium zwitterion, involving HOMO–LUMO transitions in delocalized π-orbitals.

DETECTION OF ANTIBACTERIAL COMPOUND HIMANIMIDE B IN LIQUID CULTURES OF STEREUM HIRSUTUM BY HIGH-PERFORMANCE THIN-LAYER CHROMATOGRAPHY-BIOASSAY AND MASS SPECTROMETRY-BASED METHODS

Tue, 22 Sep 2026 19:53:18 +0000

Higher fungi (Basidiomycetes) are known for releasing several bioactive compounds in liquid culture media. Some studies have reported a relevant antibacterial activity in extracts from the fungus Stereum hirsutum, however, the molecules responsible have still not been described. In the present work, an effect-directed analysis (EDA) using high-performance thin-layer chromatography (HPTLC) coupled to mass spectrometry (MS) was established to detect and identify antibacterial compounds in liquid culture of the Stereum hirsutum fungus. Bioactive molecules were separated on HPTLC silica gel 60 F₂₅₄ plates using a mobile phase composed of toluene and ethyl acetate (6.3 + 3.7 v/v), and the antibacterial compound was detected in situ on the plate by applying the Bacillus subtilis bioassay. By HPTLC/MS and liquid chromatography (LC)/MS, the antibacterial compound was identified as himanimide B, an N-hydroxylated maleimide derivative with potent antibacterial activity. To the best of our knowledge, himanimide B is reported for the first time as a secondary metabolite produced by liquid cultures of Stereum hirsutum.