This study aimed to investigate the effect of linoleic acid and α-linolenic acid mixtures on acute liver injury and the intestinal microflora diversity in mice. In total 80 specific pathogen free (SPF) Kunming mice were divided into eight groups: normal, CCl₄-induced model, positive control, and linoleic acid/α-linolenic acid mixtures at ratios of 4:1, 2:1, 1:1, 1:2 and 1:4. Serum immune functions and intestinal microflora structure in each group of mice were determined. The results showed that linoleic acid and α-linolenic acid mixtures could significantly reduce the activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (P < 0.05), decreased liver and spleen indices (P > 0.05), and decreased the content of malondialdehyde (MDA) as well as the expression levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in liver cells (P < 0.05) compared with CCl₄-induced model. These changes were consistent with the results of liver histopathological observation. High throughput sequencing results showed that the diversity of intestinal microflora in the model group dropped significantly compared with normal group (P < 0.05), while the diversity and abundance of intestinal microflora significantly increased after intervention with the 2:1 mixture of linoleic acid/α-linolenic acid compared with the CCl₄ model group (P < 0.05), and its structure also changed. Moreover, the most prominent hepatoprotective effect was observed with the 2:1 mixture of linoleic acid and α-linolenic acid, which was basically consistent with that of silybin as a positive control. These results not only confirm the hepatoprotective effect of linoleic acid/α-linolenic acid mixtures, but also provide a theoretical basis for the scientific intake of linoleic acid/α-linolenic acid mixtures and serve as a guide for future development and application of hepatoprotective agents.

In order to explore the anti-tumor activity of Perilla frutescens seed polysaccharide (PFSP), the crude polysaccharide was obtained from Perilla frutescens seeds by traditional solvent extraction and purified by DEAE-52 cellulose and dextran G-100 column chromatography, and the effect of the purified polysaccharide on the immune system of H₂₂ tumor bearing mice was determined. The results showed that the yield of the crude polysaccharide was 8.38%. After separation and purification, three polysaccharide fractions, named PFSP-1, PFSP-2 and PFSP-3, were obtained. PFSP-1 was composed of mannose, galactose, xylose and arabinose (at a molar ratio of 0.01:0.06:0.11:0.81). PFSP-2 was composed of mannose, xylose and arabinose (at a molar ratio of 0.28:0.28:0.41). PFSP-3 was composed of rhamnose, glucuronic acid, glucose, galactose, xylose and arabinose (at a molar ratio of 0.013:0.024:0.040:0.080:0.120:0.700). The three polysaccharides all displayed absorption peaks characteristic of polysaccharides and were identified as pyran-type polysaccharides.The anti-tumor effect of PFSP-2 was significantly higher than that of PFSP-1 and PFSP-3 (P < 0.05). Furthermore, PFSP-2 could significantly reduce the concentrations of lactate dehydrogenase and aldolase and interleukin (IL)-10 (P < 0.05), increase the concentrations of IL-2 and tumor necrosis factor α, down-regulate the expression of antiapoptotic protein Bcl-2, and up-regulate the expression of apoptotic protein Bax compared with the model group (P < 0.05). These results indicate that PFSP-2 can inhibit the growth of tumor cells in vivo by improving the immune system of mice.