Effects of nitrogen level on growth of Tetrastigma hemsleyanum and phytochemical content and antioxidant activity in stems and leaves / 中国中药杂志

As a rare endangered medical plant that newly cultivated,little experimental information is available for growth and metabolites of Tetrastigma hemsleyanum in response to nitrogen( N). The effects of different levels of N on growth of T. hemsleyanum and the content of phytochemicals( polysaccharide,total flavonoids and phenolics) and antioxidant activity( ABTS and FRAP) in stems and leaves were investigated in this study. A certain amount of N had positive effects on most of biological traits,and excessive dose of N went against growth of T. hemsleyanum. With N levels decreased,the polysaccharide content in stems and leaves had no significant change,while the total flavonoid and phenolic content,and antioxidant activities increased steadily. Antioxidant activities and total flavonoid and phenolic content had significant positive correlation. Excessive N fertilizer should be avoided by cultivation.

Low-grade slightly elevated and polypoid colorectal adenomas display differential ß-catenin-TCF/LEF activity, c-Myc, and cyclin D1 expression.

AIM: To comparatively investigate the cellular and molecular characteristics of low-grade slightly elevated adenomas and polypoid adenomas. METHODS: Colorectal tumors were collected from 24 patients with slightly elevated adenomas and 23 patients with polypoid adenomas. Five commonly mutated genes (APC, BRAF, KRAS, NRAS, and PIK3CA) were selected for mutational analysis. Paraffin-embedded tumor sections were used to calculate the apoptotic index (AI) and Ki-67 labeling index (KLI). Two pure colorectal epithelial cell lines were created by pooling the slightly elevated and polypoid tumors. Western blots, luciferase assays for ß-catenin-T-cell factor protein/ß-catenin-lymphoid enhancer factor (ß-catenin-TCF/LEF)-driven transcriptional activity, and caspase activity assays were conducted on the two cell lines. RESULTS: Slightly elevated lesions showed a significantly lower APC mutational frequency and a significantly higher KRAS mutational frequency (both P < 0.05). Slightly elevated lesions showed a significantly lower AI (P < 0.05). ß-catenin and ß-catenin-TCF/LEF-driven transcriptional activity was significantly upregulated in slightly elevated lesions (both P < 0.05). In slightly elevated lesions, c-Myc was significantly downregulated, while cyclin D1 was significantly upregulated (both P < 0.05). ß-catenin-TCF/LEF-driven transcriptional activity was negatively correlated with c-Myc (ρ = -0.78). Slightly elevated lesions displayed significant Bcl-2 and Bcl-xL upregulation (both P < 0.05) along with significant decreases in caspase-9 and caspase-3 activity (both P < 0.05). c-Myc was negatively correlated with Bcl-2 and Bcl-xL (ρ = -0.74 and -0.78, respectively). CONCLUSION: The lower apoptotic activity of low-grade slightly elevated adenomas can be partly attributed to upregulated ß-catenin pathway activity and downregulated c-Myc expression.