Antioxidant activity and rat C6 nerve cell cytoprotection ability of anthocyanins from mulberry juice

本研究探討桑椹汁 (Mulberry juice) 花青素對於神經細胞的保護功效。研究結果顯示，冷凍乾燥後的桑椹汁粉末 (Mulberry juice powder, MJP) 含有約19 mg/g之花青素；經過固相萃取裝置純化後凍乾之桑椹汁花青素萃取物粉末 (Anthocyanin extract from ulberry juice, AEMJ) ，其總花青素含量高達243 mg/g。HPLC 分析結果則顯示桑椹汁中花青素組成主要為cyanindin-3-glucoside 以及 cyanidin-3-rutinoside。在體外 (in vitro) 抗氧化能力方面，MJP 濃度提高至 4 mg/ml 時，1,1-diphenyl-2-picrylhydrazyl (DPPH) 自由基清除能力可達約81%；花青素萃取物自由基清除能力與兒茶素相當，當濃度達到 1 mg/ml時，清除能力高於兒茶素，約為90%。MJP 的還原力隨著濃度升高，吸光值也提高，當濃度達2 mg/ml時，吸收強度約為1.58；AEMJ的還原力則與兒茶素相似，當濃度到達0.25 mg/ml時，吸收強度已達2左右。細胞實驗方面，以大鼠神經瘤 C6 細胞缺氧模式作為神經元細胞保護之評估模式。以5 mM Na2S2O4 處理誘導缺氧之控制組細胞存活率為60.98%；缺氧誘導前，共培養之 MJP濃度提高至25 μg anthocyanin/ml，缺氧模式 C6 細胞存活率為89.74%；共培養之AEMJ濃度達50 μg anthocyanin/ml時，缺氧模式 C6細胞存活率為92.21%。在細胞內源性抗氧化能力測試方面，隨著 AEMJ 處理濃度增加，細胞 glutathione 有上升的趨勢，但 superoxide dismutase則有減少的趨勢。實驗結果顯示 MJP 及 AEMJ 確實有保護缺氧模式 C6 細胞之功效。This study investigated the cytoprotection effect of mulberry juice (MJ) anthothyanin on neuronal glial cell. The results showed that freeze dried mulberry juice powder (MJP) contained 19 mg /g anthocyanin. After purified with solid phase extraction device, anthocyanin content in freeze dried anthocyanin extract from mulberry juice (AEMJ) increased to 243 mg/g. The HPLC analysis revealed that cyanindin-3-glucoside and cyanidin-3-rutinoside are the major anthocyanin in AEMJ. The results of in vitro antioxidant test revealed that the DPPH free radical scavenging ability of MJP achieved to 81% at a concentration of 4 mg/ml. The DPPH free radical scavenging ability of 1 mg/ml AEMJ achieved to 90%, higher than that of catechin at the same concentration. The reducing power of MJP increased with the treated concentration. The absorption value was about 1.58 with the treated concentration of 2 mg/ml. The reducing power of AEMJ, similar to catechin, achieved to 2 at a concentration of 0.25 mg/ml. The rat glial tumor C6 cell was used for investigating the cytoprotection ability of MJP or AEMJ under hypoxia condition induced with Na2S2O4. The cell viability was 60.98 % for hypoxia rat glial tumor C6 cell control group at Na2S2O4 concentration of 5 mM. The cell viability of hypoxia C6 cells was 89.74% when pre-incubated with MJP contains 25 μg /ml anthocyanin. The cell viability of hypoxia C6 cells was 92.21% when pre-incubated with AEMJ contains 50 μg /ml anthocyanin. The intercellular antioxidant glutathione of hypoxia C6 cells increased, however, the superoxide dismutase activity of hypoxia C6 cells decreased, when pre-cultured with AEMJ. The results indicated that both MJP and AEMJ possess cytoprotection ability on hypoxia rat C6 glial cells