Transformed root ("hairy root") cultures have been shown to be a good model for the study of many secondary metabolites. However, economically important compounds such as asiaticoside and madecassoside are produced in insignificant amounts in the root of Centella asiatica (L.) Urban. To overcome this problem, C. asiatica was transformed using Agrobacterium rhizogenes strain R1000 that harbors pCAMBIA1302 encoding the hygromycin phosphotransferase (hpt) and green fluorescence protein (mgfp5) genes and the hairy culture was coupled with elicitation technique. Hairy roots were obtained at a frequency of up to 14.1% from a tissue junction between the leaf and petiole. Abundant hairy roots were observed when co-cultivation of the plant with A. rhizogenes was done for 7 days (36.1%). Transformation was confirmed by PCR and Southern blot analyses. Five weeks after inoculation, no asiaticoside was detected in the hairy root samples. However, when 0.1 mM methyl jasmonate (MJ) was applied as an elicitor to the culture medium for 3 weeks, a large quantity of asiaticoside was generated (7.12 mg/g, dry wt). In the case of gene expression, 12 h after MJ treatment the expression of the CabAS (C. asiatica putative beta-amyrin synthase) gene in the hairy roots is significantly different from that of the control and this level of transcripts was maintained for 14 days. Our results showed that production of C. asiatica hairy roots could be optimized and the resulting cultures could be elicited with MJ treatment for enhanced production of asiaticoside.

Ginsenosides, which are active compounds found in ginseng (Panax ginseng), are used as antidiabetic treatments. The aim of this study was to determine whether Rb2, a type of ginsenoside, regulates hepatic gluconeogenesis through AMP-activated protein kinase (AMPK) and the orphan nuclear receptor small heterodimer partner (SHP) in hyperlipidemic conditions used as an in vitro model of type 2 diabetes. Considering these results, we concluded that Rb2 may inhibit palmitate-induced gluconeogenesis via AMPK-induced SHP by relieving ER stress, a cause of gluconeogenesis.

Abstract. Fresh ginseng has a limited storage life due to the quality change caused by microbial spoilage as well as physiological deterioration. The present study investigated the effects of 1-methylcyclopropene (1-MCP) treatment, an inhibitor of ethylene action, on the microbial growth and quality maintenance of fresh ginseng during storage. Harvested fresh ginsengs were treated with 1 μL･L -1 1-MCP for 20 hours at 4°C and then stored at room temperature (RT) for 18 days or low temperature (4°C) for 160 days. After 18 days of storage at RT, the percentage weight loss in 1-MCP treated fresh ginseng (8.3%) is lower than that of control (10.1%). During long-term storage at 4°C, weight losses were increased slightly until 120 days without difference between non-treated and 1-MCP ginsengs. In contrast, after 120 days of storage at 4°C, higher increase in weight loss was observed in non-treated ginsengs than in 1-MCP treated ginsengs. Respiration rate and ethylene production of fresh ginseng were reduced by 1-MCP treatments at RT. The 1-MCP treatment also resulted in lower microbial population compared to those of non-treated ginsengs at RT. However, in ginsengs stored at 4°C for short-term (45 days), no differences were noted in weight loss and microbial population between 1-MCP treated and non-treated ginsengs. Major ginsenosides was not changed by 1-MCP treatment during the 7 days of storage at RT. Results suggest that 1-MCP treatment can be used to maintain the freshness of ginseng at room temperature for short term storage and at low temperature for long term storage. 1-MCP treatment could be applied on fresh ginseng to avoid deleterious effect of exogenous ethylene during storage and shipping. Kim et al., 2005;Yun and Lee, 1999). 또한