Valorisation of hop leaves for their bioactive compounds: Identification and quantification of phenolics across different varieties, crop years and stages of development

Extraction of bioactive compounds from papaya leaves (Carica papaya L.) by multistage countercurrent extraction as function of solvent polarity and temperature

This study investigated the effect of solvent polarity (EtOH:water, 100:0, 60:40, 40:60, 0:100 (w/w)) and temperature (35 °C, 50 °C) on bioactive compound extraction from Carica papaya L. leaves. Extraction kinetics were performed until equilibrium was reached at sample:solvent ratios of 1:10 to 1:100 (w/w), quantifying total phenols, flavonoids, alkaloids, and antiradical activity (ABTS, DPPH). The best extraction conditions were: 60 % EtOH:water at 35 °C. The thermodynamic properties (Keq = 0.07 kg of extractables in the extract/kg of extractables in the solid and M= 7.82 kg of extract/kg of inerts) enabled multistage countercurrent extraction (MCE) simulation, achieving 90 % yield in three stages, superior to single-stage methods, in both yield and solvent efficiency. These findings provide a scalable and efficient method for producing standardized papaya leaf extracts rich in antioxidants and alkaloids, directly applicable in nutraceutical formulations, functional foods, and as a natural source of compounds of interest to the pharmaceutical industry.