Effect of Different Processing Methods on Phytochemical Contents and Neuroprotective Activity of Camellia euphlebia Leaves Extract

Camellia euphlebia is a new food source and traditional folk medicine in China. Previous studies have demonstrated the antidepressant activity of Camellia euphlebia extract by both in vivo and in vitro experiments. The effects of different pretreatments on phytochemical contents and neuroprotective activity of Camellia euphlebia extract were further investigated in order to develop an optimal processing method that makes the extraction more efficient. Six different powders of Camellia euphlebia leaves were prepared by different pretreatments. The particle size and morphology were examined by using a Malvern particle size analyzer and scanning electron microscopy, respectively. The results showed that the percentage of powder particle size within a range of 0.2∼40 μm was up to 79.18% after press-shear assisted interaction technology pretreatment by 2% addition of shellfish shell powder, and the cells were broken completely. Additionally, the contents of flavonoids, polysaccharides, polyphenols, saponins, and catechin in the extract were 11.78 ± 0.62%, 34.60 ± 3.37%, 6.15 ± 0.29%, 9.43 ± 1.19%, and 1.99 ± 0.11%, respectively, which were higher than those of the other five extracts. Moreover, the extract had the strongest neuroprotective activity by comparing the neuroprotective effect of different extracts on corticosterone-induced neurotoxicity in differentiated PC12 cells. It is concluded that press-shear assisted interaction technology with 2% addition of shellfish shell powder pretreatment, to a great extent, improved the dissolution of bioactive ingredients in Camellia euphlebia.