Flavonoids are polyphenols with broad known pharmacological properties. A series of 2,3-dihydroflavanone derivatives were thus synthesized and investigated for their anti-inflammatory activities. The target flavanones were prepared through cyclization of 2′-hydroxychalcone derivatives, the later obtained by Claisen–Schmidt condensation. Since nitric oxide (NO) represents an important inflammatory mediator, the effects of various flavanones on the NO production in the LPS-induced RAW 264.7 macrophage were assessed in vitro using the Griess test. The most active compounds were flavanone (4G), 2′-carboxy-5,7-dimethoxy-flavanone (4F), 4′-bromo-5,7-dimethoxy-flavanone (4D), and 2′-carboxyflavanone (4J), with IC50 values of 0.603, 0.906, 1.030, and 1.830 µg/mL, respectively. In comparison, pinocembrin achieved an IC₅₀ value of 203.60 µg/mL. Thus, the derivatives synthesized in this work had a higher NO inhibition capacity compared to pinocembrin, demonstrating the importance of pharmacomodulation to improve the biological potential of natural molecules. SARs suggested that the use of a carboxyl-group in the meta-position of the B-ring increases biological activity, whereas compounds carrying halogen substituents in the para-position were less active. The addition of methoxy-groups in the meta-position of the A-ring somewhat decreased the activity. This study successfully identified new bioactive flavanones as promising candidates for the development of new anti-inflammatory agents.

The potential of Pinus caribaea Morelet sawdust for the removal of nickel ions (Ni²⁺) and other metallic trace ions (Co²⁺, Cr³⁺, Mn²⁺) from aqueous solutions was investigated under batch conditions. Several parameters such as size of particles, contact time, pH, initial metal and biomass concentrations, desorption conditions and reusability were evaluated on natural biomass. Biosorption was fast, effective (73%) and biomaterial can be reused after five cycles. To enhance the removal capacity of nickel, pine sawdust was modified by acidic and oxidative treatments. Cellulosic residues from sawdust sequential extraction showed great biosorption capacity (96%). In the presence of a metal mixture, oxidized sawdust had better selectivity for Cr³⁺ ions than for Ni²⁺. Pinus caribaea biomass could be an environmental, inexpensive and renewable material for the depollution of water laden with metallic trace elements.

Context and objective: In the context of valorization of wood waste from the timber industry, this work aims to study the chemical composition and to evaluate the biological capacities of coproducts from Pinus caribaea Morelet. Methods: With this mind, sawdust, bark, and knot-wood from P caribaea were analyzed by high-performance liquid chromatography-mass spectrometry. The antioxidant activities of extracts and reference compounds were assessed in vitro using 2 methods: 2.2-diphenyl-1-picrylhydrazyl and 2.2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid). For antimicrobial evaluation, coproduct extracts were assayed against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Candida albicans. Results: Despite the variable composition of sawdust, bark, and knot-wood, the composition of P caribaea is typical of the Pinus genus, with the presence of flavonoids, stilbenes, and lignans. Seven compounds were elucidated: 2 lignans (nortrachelogenin and matairesinol), 3 flavonoids (pinocembrin, pinobanksin, pinobanksin 3-acetate), 2 stilbenes (pinosylvin, pinosylvin monomethyl ether), and 1 phenolic acid (caffeic acid). Conclusion: The ethanolic extracts of bark and knots showed significant antioxidant activity. The knots showed significant antibacterial properties against S epidermidis.

Synthetic analogues of natural flavonoids have attracted attention by enhancing the bioactivity of flavonoids for the prevention and treatment of several human pathologies. In this study, carboxyflavanone derivatives were synthesized and ADMET predictions were used to assess the pharmacological profile and toxicity risks of these derivatives. The in silico evaluations are described as favourable for all compounds, in terms of biological efficacy. Carboxyflavanones have thus been evaluated for their anti-inflammatory activities on NO production in LPS-induced RAW 264.7 macrophages, and their antitumor activities against K562 chronic myeloid leukemia and HCT116 colon carcinoma cell lines. The structure-activity relationship of these derivatives was investigated by the presence of carboxyl groups at the 2, 3, and 4 positions of the flavanone B ring and by the introduction of different substituents (methyl, methoxy, bromine and aromatic cycle) in different positions on the A ring. The strongest anti-inflammatory activities were observed for compounds 4F (2′-carboxy-6-methylflavanone), 4G (2′-carboxy-7-methylflavanone), and 4H (2′-carboxy-7-methoxyflavanone), respectively. Interestingly, compounds 4F and 4G also showed the highest cytotoxicity against K562 and HCT116 cancer cell lines, along with compounds 4A (flavanone) and 4B (2’-carboxyflavanone). Since relocating the carboxyl group to positions 3’ and 4’ abrogated the bioactivity, these results indicate that the presence of the carboxyl group specifically at the ortho position of the B ring, alone or in combination with a methyl group at positions 6 or 7 of the A ring, significantly enhance bioactivity. This new SAR study thus identified favorable improvement for the development of novel anti-inflammatory and antitumor agents.