Coffee is one of the most consumed beverages worldwide. Its production generates a large amount of waste, and its use is of vital importance to prevent it from becoming a source of environmental pollution. Cuba is a country with a well-known coffee-growing tradition. Although coffee production has decreased, it is vitally important to use the waste generated in these productions to reduce environmental pollution. To know the possible use or application of coffee waste, it is necessary to know its composition. In this article, three Cuban Arabica coffee wastes (husk, parchment and spent coffee grounds) were characterized using chemical, physical and physicochemical methods. In the characterization of these wastes, SEM and EDX were used to determine their microscopic form and chemical composition. The Chesson–Datta method, ATR and TGA were used to determine whether these materials were lignocellulosic. Ash, pH and density of the waste were determined as characterization methods. The extractive content was determined and a phytochemical screening was performed to determine the groups of the secondary metabolites present.

Recent studies have demonstrated the antiproliferative and cytotoxic effects of aza-steroids and steroidal sapogenins on human cancer cell lines. The scientific community has shown a growing interest in these compounds as drug candidates for cancer treatment. In the current work, we report the synthesis of new diosgenin oxime derivatives as potential antiproliferative agents. From (25 R)-5α-spirost-3,5,6-triol (1), a diosgenin derivative, ketones 2, 3, 4, and 9 were obtained and used as precursors of the new oximes. A condensation reaction was carried out between the steroidal ketones (2, 3, 4, and 9) with hydroxylamine hydrochloride in 2,4,6-trimethylpyridine to produce five spirostanic oximes (four of them are not reported before) with a 42–96% yield. Also, a new spirostanic α, β-unsaturated cyanoketone was synthesized via Beckmann fragmentation using thionyl chloride with a 62% yield. Furthermore, we proposed a reaction mechanism with the aim of explaining such transformation.

Intensive agricultural production generates large volumes of lignocellulosic residues and contributes to heavy metal pollution, particularly copper (Cu). The valorization of these by-products as low-cost adsorbents offers a promising strategy for circular economy implementation and environmental remediation. In this study, lignin–silica nanocomposites were synthesized via a sol–gel process from two abundantly available agricultural wastes in Cuba: rice husk and coffee parchment. The nanocomposites were characterized by FT-IR, TEM and TGA methods. The nanocomposites showed a spherical shape and a diameter between 50 and 60 nm and their silica composition depended on the composition of the starting material. The nanocomposite obtained from rice husk had a silica ratio of 52 % while in the one prepared from coffee parchment it was 11 %. Adsorption capacities and adsorption behaviors with Cu(II) in water of the nanocomposites were studied. The adsorbents reached equilibrium within 10 minutes and the estimated maximum sorption capacities were 15 mg/g using rice husk as the starting material and 12 mg/g for the one prepared from coffee parchment. Nanocomposite synthesis is a promising route for lignocellulosic biomass revalorization as heavy metal adsorbents for environmental sanitation.