Spatial and genetic structure within populations of wild American ginseng (Panax quinquefolius L., Araliaceae)

Spatial structure and fine-scale genetic structure were analyzed for the medicinal plant American ginseng (Panax quinquefolius L.) to more fully understand biological processes within wild populations. P. quinquefolius has been harvested for more than 250 years and is now considered threatened or rare throughout its range. Plants within four protected and four unprotected populations were significantly clumped based on Ripley's univariate analysis. Analysis with Ripley's bivariate test determined that juvenile plants were significantly clumped with adult plants at the shortest distance classes in all populations. Although plants were highly clumped, we found that significant fine-scale genetic structure was restricted to the shortest distance classes based on estimates of coancestry (f(ij)). In most cases, estimates of f(ij) were more significant among juveniles than among adults, especially at the shortest distance classes. The spatial structure of ginseng seems to result from the establishment and persistence of plants in favorable microhabitats coupled with limited seed dispersal around maternal individuals. There were no differences in patterns of fine-scale genetic structure between protected and unprotected populations.     

Genetic diversity in harvested and protected populations of wild American ginseng, Panax quinquefolius L. (Araliaceae)

Genetic diversity was examined at 16 allozyme loci in 21 wild populations of the medicinal plant American ginseng, Panax quinquefolius L. (Araliaceae). This species has been harvested from forests in North America for more than 250 years. Average expected heterozygosity was significantly greater within protected populations (H(e) = 0.076) than within populations in which harvesting was permitted (H(e) = 0.070). More notably, genetic structure was greater among unprotected populations (G(ST) = 0.491) than among protected populations (G(ST) = 0.167). These differences in the level and distribution of genetic diversity in American ginseng populations indicate that harvesting may have significant evolutionary implications for this species. Age class structure also shifted toward smaller, nonreproductive plants in unprotected populations. Juvenile plants had lower genetic diversity (H(e) = 0.067) than reproductive plants (H(e) = 0.076) suggesting that conserving a proportion of the largest (oldest) plants in each population is important to protect reproductive fitness and the evolutionary potential of the species. Due to its high genetic structure, conservation recommendations include protecting populations throughout the range of P. quinquefolius.     

Phenological growth stages of North American ginseng (Panax quinquefolius)

The BBCH (Biologische Bundesanstalt, Bundessortenamt, Chemische Industrie) scale is used to describe the phonological growth stages of North American ginseng (Panax quinquefolius). Eight principal growth stages for germination and bud development, leaf development (crop canopy), root and perennating bud formation, peduncle elongation and inflorescence development, flowering and fruit set, development of fruit, ripening of fruit and senescence, and 42 secondary growth stages are described. A practical use of the scale is proposed with reference to the timing of application of agrochemicals for disease control.     

Ginsenoside content and variation among and within American ginseng (Panax quinquefolius L.) populations

The contents of five ginsenosides (Rg1, Re, Rb1, Rc and Rd) were measured in American ginseng roots collected from 10 populations grown in Maryland. Ginsenoside contents and compositions varied significantly among populations and protopanaxatriol (Rg1 and Re) ginsenosides were inversely correlated within root samples and among populations. The most abundant ginsenoside within a root and by population was either Rg1 or Re, followed by Rb1. Ginseng populations surveyed grouped into two chemotypes based on the relative compositions of Rg1 and Re. Four populations, including the control population in which plants were grown from TN and WI seed sources, contained roots with the recognized chemotype for American ginseng of low Rg1 composition relative to Re. The remaining 6 populations possessed roots with a distinctive chemotype of high relative Rg1 to Re compositions. Chemotype did not vary by production type (wild versus cultivated) and roots within a population rarely exhibited chemotypes different from the overall population chemotype. These results provide support for recent evidence that relative Rg1 to Re ginsenoside contents in American ginseng roots vary by region and that these differences are likely influenced more by genotype than environmental factors. Because the physiological and medicinal effects of different ginsenosides differ and can even be oppositional, our findings indicate the need for fingerprinting ginseng samples for regulation and recommended usage. Also, the High Rg1/Low Re chemotype discovered in MD could potentially be used therapeutically for coronary health based on recent evidence of the positive effects of Rg1 on vascular growth.     

Determination of major ginsenosides in Panax quinquefolius (American ginseng) using high-performance liquid chromatography

In order to determine the active ingredients in root extracts of Panax quinquefolius (American ginseng), a gradient HPLC method involving UV photodiode array detection was applied to separate and quantify simultaneously the ginsenosides Rb1, Rb2, Rc, Rd, Re, Rf and Rg1. All ginseng saponins were baseline-resolved under the selected conditions, and the detection limits were 1.0 microg/mL or less. The method has been applied to analyse ginsenosides extracted from American ginseng cultivated in both Wisconsin and Illinois. Ginsenosides Re and Rb1 were the two main ginseng saponins in the root. The amounts of Re in 5- and 7-year Illinois-cultivated samples were greater than those found in ginseng cultivated for 3 or 4 years in Wisconsin, whereas the levels of Rb1 were greater in the younger Wisconsin samples.     

Size,gender, and sex change in dwarf ginseng,Panax trifolium (Araliaceae)

Summary Flowering individuals of dwarf ginseng may be either male or hermaphroditic. I recorded the sex expression and size of individuals in three populations for three or four years in order to 1) determine whether this bimodal distribution of sex expression was due to sex changing or genetic dimorphism, and 2) test predictions about a) the relationship between size and gender, and b) the association of size change and sex change. Twenty five to 37% of the flowering individuals in each population changed gender from one year to the next. Of the plants I followed for four years, 83% changed sex and 57% changed more than once. In each of these populations as well as two others, hermaphrodites were significantly larger than males. Gender dynamics of the three populations differed, but hermaphrodites tended to become smaller and were more likely to change gender than remain hermaphroditic the following year, whereas males tended to grow larger and were more likely to remain male than to change gender. Dwarf ginseng is clearly a diphasic (sex changing) species in which sex expression is determined primarily by size. A difference between genders in the immediate resource costs of reproduction appears to be an important determinant of sex change and gender phase ratios in populations.     

Genetic diversity in North American ginseng (Panax quinquefolius L.) grown in Ontario detected by RAPD analysis

Genetic diversity within North American ginseng (Panax quinquefolius L.) grown in Ontario was investigated at the DNA level using the randomly amplified polymorphic DNA (RAPD) method via the polymerase chain reaction (PCR). A total of 420 random decamers were initially screened against DNA from four ginseng plants and 78.8% of them generated RAPD fragments. Thirty-six of the decamers that generated highly repeatable polymorphic RAPD markers were selected for further RAPD analysis of the ginseng population. With these primers, 352 discernible DNA fragments were produced from DNA of 48 ginseng plants, corresponding to an average of 9.8 fragments per primer, of which over 45% were polymorphic. The similarity coefficients among the DNA of ginseng plants analyzed were low, ranging from 0.149 to 0.605 with a mean of 0.412, indicating that a high degree of genetic diversity exists in the ginseng population. Lower levels of genetic diversity were detected among 3-year-old ginseng plants selected on the basis of greater plant height than among the plants randomly selected from the same subpopulation or over the whole population, suggesting that genetic factors at least partly contribute to morphological variation within the ginseng population and that visual selection can be effective in identifying the genetic differences. The significance of a high degree of genetic variation in the ginseng population on its potential for improvement by breeding is also discussed.     

Extractable polysaccharides of Panax quinquefolius L. (North American ginseng) root stimulate TNFalpha production by alveolar macrophages.

We have investigated the immunostimulatory activity of the medicinal plant Panax quinquefolius L. (North American ginseng). Rat alveolar macrophages were treated with different extracts from 4-year old roots, and tumour necrosis factor alpha (TNF) production was used as a measure of immunostimulatory activity. Aqueous extracts of P. quinquefolius root (1-100 microg/ml) were found to significantly stimulate alveolar macrophage TNF release. Both a P. quinquefolius methanol extract containing ginsenosides (but no polysaccharides), and pure ginsenoside-Rb1, the major ginsenoside present in P. quinquefolius, were found to be inactive as TNF-stimulating agents. Significant TNF-stimulating activity was found in the extractable polysaccharide fraction, which was hydrolyzed and found to contain glucose, galactose, arabinose, rhamnose, and mannose. This represents the first evidence that North American ginseng exerts cytokine-stimulating activity on macrophages.     

Allozyme variation in American ginseng (Panax quinquefolius L.): Variation, breeding system, and implications for current conservation practice

Sustained harvest of wild North Americanginseng (Panax quinquefolius L.) for overtwo centuries has led to heightenedconservation concern and a recent interest inthe population genetics of this species. Thisstudy examined allozyme variation from 32 wildand 12 cultivated populations of Americanginseng to: (1) document the amount anddistribution of genetic variation over a wideportion of the species' natural range, (2)examine genetic differences between wild andcultivated populations, and (3) provideindirect estimates of its breeding system. Strong genetic differences between wild andcultivated populations were found in the amountof variation within populations and thedistribution of variation among populations. Wild populations were significantly lower inall within-population diversity measures, butcontained significantly higher levels ofvariation partitioned among populations. Similarities between wild and cultivatedpopulations were also found. As a whole,cultivated and wild groups shared nearly allalleles, and populations of both groups showedstrong homozygote excess compared toexpectations under random mating. Thehomozygote excess is best explained by highlevels of selfing. In wild populations,significant correlations were found betweengenetic diversity and estimated populationsize, and between interpopulation geneticdistance and geographic distance. Overall, theresults for wild populations suggest that theyare influenced by high levels of genetic driftand low migration among populations. Conservation implications for American ginsengare discussed with particular emphases on: (1)the current debate surrounding the existence ofwild populations, (2) the ongoing practice ofintroducing cultivated seed into wildpopulations, and (3) the collection of geneticmaterial for the establishment of breedingprograms.     

Elevated temperatures increase leaf senescence and root secondary metabolite concentrations in the understory herb Panax quinquefolius (Araliaceae)

The response of understory species to elevated temperatures is not well understood but is important because these plants are highly sensitive to their growth conditions. Three-year-old plants of Panax quinquefolius, an understory herb endemic to the eastern deciduous forests of North America, were grown in a greenhouse at 25/20°C (day/night) or 30/25°C for one growing season and analyzed each month. Plants grown at high temperatures had an early onset of leaf senescence and therefore accumulated less carbon. From May to July, P. quinquefolius grown at high temperatures had decreased photosynthesis (52%), stomatal conductance (60%), and root and total biomass (33% and 28%, respectively) compared to plants grown at low temperatures. As P. quinquefolius prepared to overwinter, plants grown at high temperatures had less root biomass (53%) than plants in low temperatures. The amount of storage-root ginsenosides was unaffected by temperature, and differences in storage root size may explain why plants grown at high temperatures had greater concentrations of storage root ginsenosides (49%) than plants grown at low temperatures. Panax quinquefolius is clearly sensitive to a 5°C increase in temperature, and therefore other understory species may be negatively impacted by future increases in global temperature.     

Decreased Hill reaction rates and slow turnover of transitory starch in the obligate shade plant Panax quinquefolius L. (American ginseng)

To identify physiological processes that might limit photosynthesis in Panax quinquefolius L. (American ginseng) a comparison has been made with Panax ginseng C.A. Meyer (Korean ginseng), Pisum sativum L. (pea) and Spinacia oleracea L. (spinach). The quantum yield of oxygen evolution in intact leaves and isolated thylakoid membranes was found to be smaller in ginseng than in pea or spinach. However, the number of photosystem II (PSII) centers on a chlorophyll basis was found to be similar in all species. This suggests that ginseng thylakoid membranes possess relatively more inactive PSII centers than thylakoids of pea and spinach when grown under similar conditions. Unexpectedly, whole-chain electron transport from water to methyl viologen, and partial photosystem I reactions, demonstrated that electron transport rates to methyl viologen were anomalously low in P. quinquefolius and P. ginseng. Additionally, at elevated light intensities, intact leaves of P. quinquefolius were more susceptible to lipid peroxidation than pea leaves. In plants grown at a light intensity of 80 micro mol photons m(-2) s(-1) the levels of fructose and starch were higher in both ginseng species than in pea or spinach. Significantly, the level of starch in P. quinquefolius was relatively constant throughout the entire 12 h/12 h light/dark cycle and remained high after an extended dark time of 48 h. In addition, P. quinquefolius had lower activities of alpha-amylase and beta-amylase than P. ginseng, pea and Arabidopsis thaliana (L.) Heynh. The significance of the elevated levels of leaf starch in P. quinquefolius remains to be determined. However, the susceptibility of P. quinquefolius to photoinhibition may arise as a consequence of a reduced fraction of active PSII centers. This may result in the normal dissipative mechanisms in these plants becoming saturated at elevated, but moderate, light intensities.     

Changes in physicochemical properties,enzymatic activities,and the microbial community of soil significantly influence the continuous cropping of Panax quinquefolius L. (American ginseng)

Plant and Soil - In the production of the natural medicinal plant American ginseng, replantation typically fails due to continuous cropping obstacles. However, the cause is still not clear and...     

Three sesquiterpene hydrocarbons from the roots of Panax ginseng C.A. Meyer (Araliaceae)

The volatile constituents of the roots of Panax ginseng C.A. Meyer have been investigated after hydrodistillation and analysed by means of different analytical methods. Besides several compounds already known three sesquiterpene hydrocarbons have been isolated from the essential oil. Structure elucidation of the bicyclic panaxene as well as of the tricyclic panaginsene and ginsinsene was performed by MS and NMR. They have been identified as (1R*,2S*,5S*)-2-ethenyl-1(1-methylethenyl)-2,6,6-trimethylbicyclo[3.2.0]heptane (panaxene), (1S*,8S*,11R*)-4,7,7,11-tetramethyltricyclo[6.3.0.0(1,5)]undec-4-ene (panaginsene) und (1R*,6R*,7R*)-3,7,10,10-tetramethyltricyclo[4.3.2.0(2,6)]undec-2-ene (ginsinsene).     

Mechanistic studies on protopanaxadiol, Rh2, and ginseng (Panax quinquefolius) extract induced cytotoxicity in intestinal Caco-2 cells

Certain ginsenosides, also known as triterpene glycosides, have been recently reported to have a characteristic effect on cultured intestinal and leukemia cell growth. Ginsenoside aglycones 20(S)-protopanaxadiol (PD), 20(S)-protopanaxatriol (PT), and ginsenoside Rh2 have been identified as having a strong effect on reducing cell viability. Furthermore, ginsenoside Rh2 is thought to be a rare ginsenoside not found in all ginseng products. Rather, Rh2 has been recently reported to be a breakdown product of thermal processing of North American ginseng. In this study, pure ginsenosides PD, PT, Rh2 standards and an enriched Rh2 fraction derived from ginseng leaf were tested in cultured Caco-2 cells for relative cytotoxic potency. PD and Rh2 LC50 were similar after 24 to 72 h, whereas a drop in PT LC50 occurred later at 48 and 72 h. Furthermore, PD and Rh2 affected membrane integrity as indicated by LDH secretion earlier than PT and the enriched Rh2 fraction (P < or = 0.05). Ginsenoside Rh2 showed the greatest (P < or = 0.05) build up of necrotic cells (18.3 +/- 0.1%) at the respective LC50 after 24 h and PD (21.3 +/- 0.3%) showed the largest effect after 44 h of exposure. The effect on apoptotic cells at 44 h of treatment were significantly different (P < or = 0.05) for Rh2 (21 +/- 0.4%), PD (14.6 +/- 0.1%), enriched Rh2 leaf fraction (9.9 +/- 0.6%), and PT (2.3 +/- 0.1%) treatments. Caco-2 caspase-3 activity was different between ginsenoside exposure; Rh2 (10.6 +/- 0.3 nM pNA) had the greatest (P < or = 0.05) activity followed by the enriched Rh2 leaf fraction (8.3 +/- 0.2 nM pNA), PT (7.3 +/- 0.3 nM pNA). The PD (4.8 +/- 0.04 nM pNA) treatment was similar to untreated cells (4.3 +/- 0.05 nM pNA) in caspase-3 activity. These results show variable bioactive response in cultured intestinal cell to specific ginsenosides and an enriched Rh2 North American ginseng extract which may be explained on basis of hydrophobic/hydrophilic balance.     

Pollen ultrastructure of Panax(the ginseng genus, Araliaceae),an eastern Asian and eastern NorthAmerican disjunct genus

Pollen of ten species of Panax and six species of Aralia was examined in light microscopy and scanning and transmission electron microscopy. Grains of both genera have similar complex apertures, short columellae, and overlapping tectal sculptures, suggesting a close relationship. Most species of Panax have pollen characterized by striato-reticulate tecta, short columellae, thick foot layers, costa ectocolpi, and lalongate endoapertures. The eastern North American P. trifolius, commonly known as the dwarf ginseng, has a distinctive pollen morphology and exine structure, supporting the hypothesis of its phylogenetically isolated position. Pollen of the eastern Asian P. ginseng (ginseng) can be distinguished from the eastern North American P. quinquefolius (American ginseng) by differences in ultrastructure. The monophyly of the three medicinally important species, P. ginseng, P. notoginseng, and P. quinquefolius, suggested by triterpenoid data, is not supported by pollen data. The results of the pollen study are generally congruent with those from the sequences of nuclear ribosomal DNA.     

西洋参与人参中人参皂甙含量的比较

采用ＴＬＣ和ＨＰＬＣ方法分析比较西洋参（Ｐａｎａｘ ｑｕｉｎｑｕｅｆｏｌｉｕｍ Ｌ．）、人参（Ｐ．ｇｉｎｓｅｎｇ Ｃ．Ａ．Ｍｅｙ．）及其加工品红参（ｒｅｄ ｇｉｎｓｅｎｇ）,以及不同规格的西洋参中人参皂甙的含量。结果表明,西洋参中人参皂甙总量及人参二醇型皂甙的含量明显高于人参及红参,且含有１种人参及红参中未发现的未知人参皂甙Ｒｘ,但不含人参及红参中含有的Ｒｆ;人参中人参二醇型皂甙的含量高于人参三醇     

Somatic embryogenesis and plantlet regeneration in American ginseng (Panax quinquefolium L.)

Summary Somatic embryogenesis in American ginseng (Panax quinquefolium L.) was investigated from three explant sources (root, leaf and epicotyl) with Murashige and Skoog (MS) medium containing different growth regulators. Mature roots and leaves obtained from 3- to 5-yr-old field-grown plants, and seedling leaves and epicotyls from plantlets grownin vitro, were evaluated. From root and epicotyl explants, callus development was optimal with 3,6-dichloro-o-anisic acid (dicamba) (9.0 μM) and kinetin (KN) (5.0 μM) as the growth regulators. When these calluses were transferred after 3 mo. to dicamba alone (9.0 μM), somatic embryo formation was observed at an average frequency of 15.6% in root explants after an additional 3 mo., and 2% in epicotyl explants after an additional 6 mo. No plantlets were recovered because the embryos germinated to form shoots with no roots. From leaf explants, callus growth was optimal with α-naphthaleneacetic acid (NAA) at 10.0 μM and 2,4-dichlorophenoxyacetic acid (2,4-D) at 9.0 μM. Somatic embryos developed on this medium, with the highest frequency (40%) obtained after 3 mo. from seedling-leaf explants. Calluses on mature leaves formed somatic embryos after 7 mo. with NAA/2,4-D at an average frequency of 30%. Transfer of these somatic embryos to 6-benzyladenine/gibberellic acid (4.4/2.9 μM) promoted shoot development but no roots were observed. Up to 100% of germination was observed within 6 wk on half-strength MS salts containing activated charcoal (1%) and on NAA/2,4-D (5.0/4.5 μM) with charcoal (1%). On the latter medium, somatic embryos enlarged and frequently gave rise to new somatic embryos after a brief callusing phase. The embryos germinated through a two-stage process, involving the elongation of the root followed by the formation of a shoot. The highest recovery of ginseng plantlets from germinated embryos was 61.0%. Following transfer to potting medium and maintenance under conditions of high humidity and low light intensity, the plantlets elongated and developed new leaves. A high percentage (50%) of these plants have been acclimatized to soil.     

The influence of lead and arsenite on the inhibition of human breast cancer MCF-7 cell proliferation by American ginseng root (Panax quinquefolius L.)

American ginseng root (Panax quinquefolius) has a number of purported therapeutic effects, including inhibition of cancer cell proliferation. The ability of environmentally relevant heavy metals to alter ginseng effects on cancer cell growth was the subject of this study. A water extract of American ginseng root was applied alone or in combination with physiologically relevant doses of either lead (Pb) or arsenite to MCF-7 breast cancer cells in vitro and effects on cell proliferation were determined. Ginseng alone produced a significant dose-dependent inhibition of MCF-7 cell proliferation starting at 0.5 mg ml(-1). Treatment of MCF-7 cells with 2.5 microM arsenite significantly decreased MCF-7 cell proliferation (p < 0.01). When cells were treated with arsenite (1.25 or 2.5 microM) in combination with ginseng extract (0.5 mg ml(-1)), there was an apparent synergistic inhibition of cell proliferation. Treatment of MCF-7 breast cancer cells with 50 microM Pb significantly decreased cell proliferation relative to control (p < 0.01), and concomitant ginseng and Pb treatment did not lead to a further decrease. These results suggest that contaminant heavy metals, some of which have been detected in ginseng root extracts or commercial ginseng preparations, may alter the biological activity of ginseng.     

Rhexocercosporidium panacis sp. nov., a new anamorphic species causing rusted root of ginseng (Panax [corrected] quinquefolius)

A new species of the anamorphic genus Rhexocercosporidium is described. Isolates of a Rhex-Rhexocercosporidium sp. were obtained from ginseng (Panax quinquefolius) roots with symptoms of rusted root. These isolates were found to be genetically and morphologically distinct from the only described species in this genus, R. carotae. Sequence data from the ribosomal DNA region spanning the internal transcribed spacers 1 and 2 and from a portion of the 3-tubulin gene of the ginseng Rhexocercosporidium were compared to those of R. carotae. Parsimony analyses of sequence data showed that R. carotae and the ginseng isolates belonged to distinct but closely related clades. Conidia of a typical ginseng isolate were significantly shorter and possessed fewer septa than R. carotae but shared rhexolytic secession of conidia with R. carotae. The binomial Rhexocercosporidium panacis is proposed to accommodate isolates of this genus that are associated with the rusted root disease.