Investigation of ziziphus jujube seeds as a new source of taxifolin and silibinin with three different extraction methods

Many food wastes are potentially worth examining due to the beneficial phenolic substances they contain. Jujube seeds are richer than jujube fruit pulp in terms of bioactive substances, especially phenolics. In this study, the amounts of taxifolin, silibinin, kaempferol, quercetin, rutin, and apigenin in jujube seed extracts obtained by conventional Soxhlet (CSE), ultrasonic assisted (UAE), and supercritical fluid extraction (SFE) methods were investigated. The method yields were examined by comparing the amounts of obtained bioactive substances. Total amounts of these bioactive compounds were 837.91 µg/g, 242.24 µg/g, and 51.44 µg/g by UAE, CSE, and SFC methods, respectively. These substances were found to be 470.82 ± 8.21 µg/g taxifolin, 134.4 ± 3.15 µg/g silibinin, 112.52 ± 3.36 µg/g kaempferol, 60.04 ± 0.25 µg/g quercetin and 54.63 ± 0.69 µg/g rutin in UAE extraction, which was the most efficient method. Taxifolin and silibinin were predominant phenolics. The high levels of taxifolin and silibinin in jujube seeds are known to prevent, treat and reduce the risk of cancer and chronic diseases. As a promising assessment, the examined jujube seed oil appears to be a usable source for food supplementation or pharmaceutical purposes with its high taxifolin and silibinin potential.