The demand for bioactive secondary metabolites of natural origin is increasing every day. Micropropagation could be a strategy to respond more quickly to market demands, regardless of seasonality. This research aims to evaluate in vitro-grown plants of two hop varieties, namely Columbus and Magnum, as a potential source of bioactive compounds. The extracts were characterized in terms of total phenolic content by a Folin–Ciocalteu assay and antioxidant capacity by DPPH^•, ABTS⁺, and FRAP assays. The bioactive compound profile of the extracts from both varieties was determined by using UPLC-ESI-QqQ-MS/MS. The results confirmed richness in (poly)phenols and other secondary metabolites of the in vitro-grown hop plantlets. Thirty-two compounds belonging to the major families of phytochemicals characteristic of the species were identified, and twenty-six were quantified, mainly flavonoids, including xanthohumol and isoxanthohumol, phenolic acids, as well as α- and β-acids. This study confirms the validity of in vitro-derived hop plantlets as source of bioactive compounds to be used in the nutraceutical, pharmaceutical, and food industries.

(1) Background: Traditionally, hop is propagated using rhizome fragments or herbaceous stem cuttings. Micropropagation, therefore, offers a viable alternative for the large-scale production of healthy, genetically uniform plants, regardless of the season and within confined spaces. A temporary immersion system (TIS) facilitates plant propagation by alternating immersions of microcuttings in liquid culture medium with dry periods, preventing gas accumulation through forced ventilation. (2) Methods: In this study, the response of hop plantlets, cv. Columbus, cultured in media with and without sucrose, in solid and liquid culture systems (Plantform^TM bioreactor), was evaluated, considering its effect on morpho-physiological parameters, on the total phenolic content, and on antioxidant capacity. Moreover, to make the TIS more efficient, the effect of immersion duration (three and six minutes every twelve hours) was evaluated. (3) Results: The presence of sucrose in the culture medium improved plant proliferation in both culture systems tested: solid and liquid (particularly for explants immersed for three minutes). In the TIS, plantlets with a higher antioxidant capacity were obtained when sucrose-free culture medium was used. (4) Conclusions: This study confirms the efficacy of the TIS as a hop propagation method but also as a valid tool to produce biomass to be used as a source of bioactive compounds.

Nowadays, tomato, a commercially important crop, is increasingly cultivated in a soilless cultivation system to counteract climate change. Normally, this system uses cocopeat as a substrate, but its high cost and environmental impact have led to growing interest in alternatives like biochar (BC). In addition, biostimulants, such as wood distillate (WD), a pyrolysis by-product, are increasingly being used to improve fruit yield and quality. BC was used to partially replace (2% and 5%) cocopeat in growth bags for soilless tomato cultivation. Moreover, WD (3 mL/L) was distributed in the substrate every two weeks. The effect of BC and WD on tomato plant growth, fruit quality, and substrate microbial community was investigated. The integration of BC and WD into a soilless growing system for tomato cultivation can improve the fruit quality and influence the microbial activity of the substrate. Replacing part of the cocopeat in the substrate with BC and using an agri-waste-derived biostimulant represent a step forward in making agriculture more sustainable.

Biochar, a by-product of agri-food waste, has shown benefits in plant growth and soil health. However, its use in vitro remains underexplored. This study investigates the impact of biochar supplementation in the culture medium, alone or in combination, with 6-benzylaminopurine (BAP), on kiwifruit (Actinidia chinensis var. deliciosa), cv. Tomuri proliferation. Kiwifruit explants were cultured on media enriched with 0, 4, or 6 g/L biochar, without or with BAP (0.2 mg/L), over two subcultures (SUB1 and SUB2). Parameters such as shoot and root number and length, fresh and dry weight, as well as plantlets’ total phenolic content and antioxidant activity, were measured and analyzed. Biochar enhanced plantlets proliferation, particularly with BAP. In SUB1, at 4 g/L, biochar promoted shoot production (2.00 vs. 1.63) and their length (1.50 cm vs. 0.98), independently of the presence of BAP. The presence of biochar in the BAP-free media, favored rhizogenesis; particularly in SUB2, where on average, 5.58 roots per plantlets were recorded. Biochar increased the plantlets’ total phenolic content and antioxidant activity, especially in BAP-free media. The addition of biochar as an additive to the culture medium during the kiwifruit in vitro proliferation phase could be a breakthrough outcome for the nursery sector.

In the original publication [...].

Sacha inchi (P. volubilis L.), an ancient oilseed crop native to the Amazon, is gaining attention for its high nutritional value particularly due to its ω-3-, -6-, -9-rich oil. However, most research has focused mainly on oil characterization, neglecting the potential of its by-products, such as the Sacha inchi oil-press cake (i.e., the solid residue after oil extraction). This study explores the chemical composition of Sacha inchi oil press-cake powder, focusing on fatty acid and amino acid profiles, antinutrient factors, total phenolic content, antioxidant activity, and the bioactivity of its extracts on cellular models. Fatty acid analysis revealed a high proportion of polyunsaturated fatty acids, especially α-linolenic acid (42.52%), making it a valuable resource for health-promoting applications. The protein content was also significant (41.86%), with a balanced amino acid composition, including essential amino acids such as leucine, valine, and isoleucine, which are vital for muscle protein synthesis and energy metabolism, in food and/or feed applications. Antinutritional factors were detected, including saponins (1050.1 ± 1.1 mg/100 g), alkaloids (2.1 ± 0.5 mg/100 g), and tannins (6.2 ± 0.9 mg/100 g). While these phytotoxins could limit their use in food applications, their potential antimicrobial activity highlights promising pharmacological opportunities. Total phenolic content (TPC) and antioxidant activity (AO) were evaluated using two extract mixtures differing in composition and polarity, with the acetone/water/acetic acid solvent (80/19/1 v/v/v) showing the highest antioxidant properties. The extract obtained showed cytotoxic effects against Panc-1 cancer cells, highlighting its potential in nutraceutical and pharmaceutical applications. This study underscores the unexploited potential of Sacha inchi by-products, such as the oil press-cake, as a sustainable resource of bioactive compounds for functional products, supporting circular bio-economy strategies by plant-based waste and local biodiversity valorization.