Cost-effective Isolation of Bioactive Compounds from a Discarded Bioresource - Defatted Seeds of Camellia oleifera

The Camellia oleifera oil industry is the economic mainstay in many high-poverty mountain regions of China, but the defatted seeds are currently discarded, leading to a waste of bioresources. In this work, a cost-effective technique was designed to isolate the flavonoid, saponins, and polysaccharides by ultrasonic-assisted acid-base alternative extraction. The activities of these compounds were evaluated by their DPPH and ABTS radical scavenging abilities in vitro and inflammatory inhibition in mice, and the economic efficiency was assessed. The optimal extraction conditions by response surface design were 1.6% HCl, water/seed ratio 16, extraction time 89 min, and ultrasonic power 310 W. The yields of the flavonoid, saponin, and polysaccharide were, respectively, 1.4 +/- 0.2%, 6.7 +/- 0.8%, and 22.5 +/- 1.7%. The extracts could eliminate DPPH and ABTS radicals and alleviate inflammation with concentration dependence, and showed excellent capacity in the order of flavonoid >= saponin > polysaccharides. The residue after extraction was cellulose, with a yield of 63.0 +/- 2.4%. The defatted seeds could produce a value of $11.35 per kilogram after production of the four valuable extracts, which would greatly increase the income in these high-poverty areas. This integrated extraction technique provides valuable recycling utilization of a typically discarded bioresource.