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Many ginsenoside biosynthesis-related genes have been identified in Panax ginseng. However, there is no report of the analysis of changes in gene expression induced methyl jasmonic acid (MeJA) using DNA microarray analysis. To identify the genes related to ginsenoside biosynthesis, we harvested P. ginseng adventitious roots at 0, 24, 72 and 120 h after MeJA treatment. At 120 h after MeJA elicitation, the contents of all ginsenosides increased compared to the control. We analyzed gene expression patterns in ginseng adventitious roots treated with MeJA using DNA microarray analysis and selected candidate genes related to ginsenoside biosynthesis, including genes encoding squalene synthase (SQS), squalene epoxidase (SE), dammarenediol-II synthase (DS), cytochrome P450 oxidase (CYP) and glycosyltransferase (GT). The expression patterns of these genes in MeJA-treated ginseng adventitious roots obtained by quantitative RT-PCR were consistent with those obtained by microarray analysis. Therefore, DNA microarray analysis is an efficient tool for selecting candidate genes associated with secondary metabolite biosynthesis in plants.

One objective of this study was to compare the antioxidant activity from various organs of Artemisia species and identify new organs of Artemisia species with antioxidant activity. The various organs of the Artemisia species were analyzed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, which are widely used for evaluating antioxidant activity. A. annua, A. montana, A. stolonifera and A. gmelinii found to have strong antioxidant activity. These findings reinforce the potential of plants as valuable antioxidant sources. A second objective of this study was to compare the artemisinin content from various organs of Artemisia species and identify that a new organ of Artemisia species with high artemisinin content. Artemisinin is one of the most important phytochemicals found in the Artemisia species, and has been used for the treatment of malaria all over the world. Using high-performance liquid chromatography, we analyzed the artemisinin content from various organs of the Artemisia species. The roots of A. absinthium and A. rubripes howed high contents of artemisinin. This, roots of A. absinthium and A. rubripes are suggested as alternatives to A. annua as medicinal sources of artemisinin.

Powdery mildew symptoms were observed on the upper surface of leaves of Cynanchum auriculatum in Eumseong, Korea in October 2015. Microscopic observations and molecular characteristics determined this fungus as Podosphaera sp., which is reported for the first time on Cynanchum auriculatum.

In order to produce centellosides from whole plant cultures of Centella asiatica (L.) Urban, we evaluated the synergistic effects of thidiazuron (TDZ) and methyl jasmonate (MJ) on whole plant growth and centelloside production. After 4 weeks of treatment with 0.025 mg/L of TDZ coupled with 0.1 mM MJ, the production of madecassoside and asiaticoside from whole plant cultures was estimated to be 2.40- and 2.44-fold, respectively, above that of MJ elicitation alone. When whole plants were treated with a growth regulator and an elicitor, the growth of whole plants, as compared to the controls, did not differ. Additionally, total phytosyterol content in the leaves of whole plants co-treated with MJ and TDZ was 1.08-fold greater than those of MJ alone. These results demonstrate that combined treatments not only stimulate the accumulation of centellosides in the leaves but also inhibit the reduction of phytosterol levels caused by MJ elicitation.

This study describes the identification of Panax species using a peptide nucleic acid (PNA) microarray. P. ginseng, P. quienquefolius, and P. japonicus were distinguished from each other using 5 PNA probes designed based on three single nucleotide polymorphisms (SNPs) detected in internal transcribed spacer (ITS) and 5.8S rDNA regions. Signal intensity comparison between PNA and DNA microarrays revealed that the PNA microarray provides a significantly more stable and specific fluorescent signal intensity than the DNA microarray. Three Panax species identified by the PNA microarray were denoted as barcode numbers depending on their fluorescent signal patterns of each species using 5 PNA probes (PG-ITS-116, PG-ITS-414-1, PG-ITS-414-2, PG-ITS-425-1, and PG-ITS-425-2). P. ginseng, P. quinquefolius, and P. japonicus were denoted as ‘11010’, ‘00202’ and ‘00000’, respectively. The PNA microarray developed in this study will be useful for legitimizing the distribution of ginseng in domestic and foreign ginseng markets.

In the process of screening for anti-human acyl-CoA:cholesterol acyltransferase (hACAT) agents from plant resources, we found that the 80% methanolic extract of Rhus chinensis (R. chinensis) exhibited significant antioxidative and hACAT activities in rats. Two compounds were isolated as active principles from the ethyl acetate soluble fraction of the branches of R. chinensis. The structures of compounds 1 and 2 were determined as hydroxydammarenone and semialactone, respectively, by means of MS and NMR spectroscopic analysis. Compound 1 has been isolated from this plant for the first time. Compounds 1 and 2 showed inhibitory activities on both human ACAT1 with IC50 values of 12.4, and 79.1 μM and on human ACAT2 with IC50 values of 30.5 and 76.9 μM, respectively. These results suggested that R. chinensis containing dammarane triterpenes 1 and 2 might be effective in the prevention and treatment of hypercholesterolemia or atherosclerosis via inhibitory effect on hACAT.

In this study, methyl jasmonate (MJ)-induced changes of triterpene saponins in ginseng (Panax ginseng C.A. Meyer) hairy roots and expression profiling of relevant responsive genes were analyzed. The transcription of PgSS (squalene synthase), PgSE (squalene epoxidase), and PNA (dammarenediol synthase-II) genes in hairy root cultures elicited by MJ treatment increased as compared with the controls, whereas that of PNX (cycloartenol synthase) decreased slightly. In order to select candidate genes encoding for cytochrome P450-dependent hydroxylase or glucosyltransferase associated with triterpene biosynthesis, RT-PCR analysis was conducted following MJ elicitation. No differences were observed in any expression among the five genes associated with the cytochrome P450 family, when compared to that of control. For candidates of the glucosyltransferase gene,expression of EST IDs PG07020C06, PG07025D04, and PG07029G02 was upregulated. In an effort to assess the effects of MJ elicitation on the biosynthesis of triterpene saponin, protopanaxadiol saponin (Rb group) and protopanaxatriol saponin (Rg group) contents in hairy roots were evaluated by HPLC analysis. With 7 days of MJ elicitation, levels of all ginseonsides of the two-groups increased much higher than that observed in the control. In particular, protopanaxadiol-type saponin contents increased by 5.5–9.7 times that of the control, whereas protopanaxatriol-type saponin contents were increased by 1.85–3.82-fold. In the case of Rg1 ginsenoside after MJ elicitation, the content was affected negatively in ginseng hairy root cultures.

Molecular authentication among three Panax species and within cultivars and accessions of P. ginseng was investigated using the DNA sequence in the ribosomal ITS1–5.8S–ITS2 region. Four single-nucleotide polymorphisms were identified between P. ginseng and other Panax species. In the electrophoresis profile, obtained after digestion with the enzyme TaqI, three fingerprinting patterns were obtained from cultivars and accessions of Panax species. Consequently, this authentication procedure based upon the restriction fragment length polymorphism in the ribosomal ITS1–5.8S–ITS2 region can now be utilized to differentiate these Panax species as well as major Korean cultivars such as Gopoong and Kumpoong from other cultivars and accessions in Panax species at the DNA level.

Culture conditions were optimized for somatic embryogenesis ofPanax ginseng. The highest frequency of embryo formation was obtained when tissues were excised from the middle region of the cotyledon segments of zygotic embryos. Only treatment with light could stimulate the formation of single-type somatic embryos, whereas multiple-type somatic embryos and calli were observed under dark conditions. The highest production of somatic embryos was found with an NH4 +:NO3 ratio of 21:39. Among the tested media (MS, B5, and SH), maximum formation of somatic embryos was obtained when cotyledon expiants were cultured on an 1% agar MS medium supplemented with 5% sucrose. Regenerated ginseng plantlets were transferred to an autoclaved soil mixture in the greenhouse. These transformants showed no detectable variations in their morphology or growth characteristics compared with the donor plant.