Ecology and conservation of ginseng (Panax quinquefolius) in a changing world

A systematic review of ginsenoside biosynthesis, spatiotemporal distribution, and response to biotic and abiotic factors in American ginseng

American ginseng (Panax quinquefolius) has gained recognition as a medicinal and functional food homologous product with several pharmaceutical, nutritional, and industrial applications. However, the key regulators involved in ginsenoside biosynthesis, the spatiotemporal distribution characteristics of ginsenosides, and factors influencing ginsenosides are largely unknown, which make it challenging to enhance the quality and chemical extraction processes of the cultivated American ginseng. This review presents an overview of the pharmacological effects, biosynthesis and spatiotemporal distribution of ginsenosides, with emphasis on the impacts of biotic and abiotic factors on ginsenosides in American ginseng. Modern pharmacological studies have demonstrated that American ginseng has neuroprotective, cardioprotective, antitumor, antidiabetic, and anti-obesity effects. Additionally, most genes involved in the upregulation of ginsenoside biosynthesis have been identified, while downstream regulators (OSCs, CYP450, and UGTs) require further investigation. Futhermore, limited knowledge exists regarding the molecular mechanisms of the impact of biotic and abiotic factors on ginsenosides. Notably, the nonmedicinal parts of American ginseng, particularly its flowers, fibrous roots, and leaves, exhibit higher ginsenoside content than its main roots and account for a considerable amount of weight in the whole plant, representing promising resources for ginsenosides. Herein, the prospects of molecular breeding and metabolic engineering based on multi-omics to improve the unstable quality of cultivated American ginseng and the shortage of ginsenosides are proposed. This review highlights the gaps in the current research on American ginseng and proposes solutions to address these limitations, providing a guide for future investigations into American ginseng ginsenosides.

Phenotypic and Genotypic Variation of Cultivated Panax quinquefolius

American ginseng (Panax quinquefolius) is widely used due to its medicinal properties. Ontario is a major producer of cultivated American ginseng, where seeds were originally collected from the wild without any subsequent scientific selection, and thus the crop is potentially very diverse. A collection of 162 American ginseng plants was harvested from a small area in a commercial garden and phenotyped for morphological traits, such as root grade, stem length, and fresh and dry weights of roots, leaves, stems, and seeds. All of the traits showed a range of values, and correlations were observed between root and stem weights, root dry weight and leaf dry weight, as well as root and leaf fresh weights. The plants were also genotyped using single nucleotide polymorphisms (SNPs) at the PW16 locus. SNP analysis revealed 22 groups based on sequence relatedness with some groups showing no SNPs and others being more diverse. The SNP groups correlated with significant differences in some traits, such as stem length and leaf weight. This study provides insights into the genetic and phenotypic diversity of cultivated American ginseng grown under similar environmental conditions, and the relationship between different phenotypes, as well as genotype and phenotype, will aid in future selection programs to develop American ginseng cultivars with desirable agronomic traits.

Discrimination for geographical origin of Panax quinquefolius L. using UPLC Q-Orbitrap MS-based metabolomics approach

American ginseng, Panax quinquefolius L., is an important medicinal plant with multiple pharmacological effects and high nutritional value. American ginseng from different geographical origins varies in quality and price. However, there was no approach for discriminating American ginseng from different geographical origins to date. In this study, a metabolomic method based on the UPLC-Orbitrap fusion platform was established to comprehensively determine and analyze metabolites of American ginseng from America and Canada, Heilongjiang, Jilin, Liaoning, and Shandong provinces in China. A total of 382 metabolites were detected, including 230 saponins, 30 amino acids and derivatives, 27 organic acids and derivatives, 25 lipids, 17 carbohydrates and derivatives, 10 phenols, 8 nucleotides, and derivatives, as well as 35 other metabolites. Metabolite differences between North America and Asia producing areas were more obvious than within Asia. Twenty metabolites, contributed most to the differentiation of producing areas, were identified as potential markers with prediction accuracy higher than 91%. The results provide new insights into the metabolite composition of American ginseng from different origins, which will help discriminate origins and promote quality control of American ginseng.

First Report of Leaf Spot of Panax quinquefolius Caused by Pestalotiopsis nanjingensis in Tennessee and the United States

American ginseng (Panax quinquefolius L.) is an herbaceous perennial understory plant. It was listed as endangered species by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (McGraw et al. 2013). Leaf spot symptoms were observed on 6-year-old cultivated American ginseng on a research plot (8 x 12 ft raised bed under a tree canopy) in Rutherford Co., TN in July 2021 (Fig. 1a). Symptomatic leaves were exhibiting light brown leaf spots with chlorotic haloes 0.5 to 0.8 cm in diameter, mostly confined within or bounded by veins. As the disease progressed, leaf spots expanded and coalesced into irregular shapes with necrotic centers, resulting in a tattered appearance of the leaf. Disease severity was about 50 to 80% of leaf area and incidence was 10% out of 20 plants. Plant tissues were surface sterilized with 10% NaOCl2 for 60s and washed thrice with sterile water and plated on potato dextrose agar (PDA). Colony growth of the isolates FBG880 and FBG881 on PDA were round, white, thick, and flocculent at the front of the plate and showed a yellowish-ringed shape on the back 10 days after incubation at 25°C (light/dark: 12/12h). Acervular conidiomata containing abundant conidia were observed on PDA. They were globose, 1.0 to 1.8 mm in diameter, and found as solitary or aggregated clusters. Conidia contained five cells (average 13.03±3.50 x 14.31±3.93 µm, n = 30). The middle three cells were light brown to brown. The basal and apical cells were nearly triangular, and transparent, with two to three (7:3 ratios, respectively) apical appendages (average 13.27±3.27 µm) and a basal appendage (average 4.50±0.95 µm, n = 30). To determine pathogen identity, total DNA was extracted using DNeasy PowerLyzer Microbial Kit from fungal colonies on PDA (isolates FBG880 and FBG881). The ribosomal internal transcribed spacer (ITS) region, beta-tubulin (BT), and translation elongation factors 1-α (EF1) genetic markers were amplified using ITS1/ITS4 (White et al. 1990), T1/T2 (Stefańczyk et al. 2016), and EF1/EF2 (O'Donnell et al. 1998), respectively. The sequences (GenBank accession nos. ITS: OQ102470 and OQ103415; BT: OQ107059 and OQ107061; and EF1: OQ107060 and OQ107062) are 100% similar to Pestalotiopsis nanjingensis (CSUFTCC16 and CFCC53882) (Jiang et al. 2022; Li et al. 2021) (Fig. 2). Based on morphology and molecular characteristics, the isolates were identified as P. nanjingensis. To conduct the pathogenicity trial, six healthy 1-year-old American ginseng plants, germinated from seeds and grown in the greenhouse were spray inoculated with a conidial suspension (1×106 conidia/ml) (FBG880). Six control plants were sprayed with sterile water. All plants were covered with plastic bags and incubated in a greenhouse set at 21 to 23°C, 70% relative humidity and 16-h photoperiod. After 48 h, bags were removed and plants were maintained under the same conditions. After one month, while control plants remained asymptomatic (Fig. 1b), inoculated plants started to exhibit symptoms resembling those in the research plot (Fig. 1c). Fungal isolates resembling P. nanjingensis in cultural characters were consistently recovered from inoculated plants and their identity as P. nanjingensis was confirmed by DNA sequencing. To our knowledge, this is the first report of leaf spot disease caused by P. nanjingensis on American ginseng. Identification of this pathogen and confirmation of its pathogenicity are fundamental to future disease management approaches.

Species discrimination of novel chloroplast DNA barcodes and their application for identification of Panax (Aralioideae, Araliaceae)

Certain species within the genus Panax L. (Araliaceae) contain pharmacological precious ginsenosides, also known as ginseng saponins. Species containing these compounds are of high commercial value and are thus of particular urgency for conservation. However, within this genus, identifying the particular species that contain these compounds by morphological means is challenging. DNA barcoding is one method that is considered promising for species level identification. However, in an evolutionarily complex genus such as Panax, commonly used DNA barcodes such as nrITS, matK, psbA-trnH, rbcL do not provide species-level resolution. A recent in silico study proposed a set of novel chloroplast markers, trnQ-rps16, trnS-trnG, petB, and trnE-trnT for species level identification within Panax. In the current study, the discriminatory efficiency of these molecular markers is assessed and validated using 91 reference barcoding sequences and 38 complete chloroplast genomes for seven species, one unidentified species and one sub-species of Panax, and two outgroup species of Aralia L. along with empirical data of Panax taxa present in Vietnam via both distance-based and tree-based methods. The obtained results show that trnQ-rps16 can classify with species level resolution every clade tested here, including the highly valuable Panaxvietnamensis Ha et Grushv. We thus propose that this molecular marker to be used for identification of the species within Panax to support both its conservation and commercial trade.

Global Trends in Research on Wild-Simulated Ginseng: Quo Vadis?

To the best of our knowledge, no study has systematically reviewed and analyzed the research trends of wild-simulated ginseng (WSG) used for food or medicinal purposes in many countries. WSG, a non-timber forest product, has been traditionally produced using agroforestry practices, and it has been consumed in various ways for a long time. WSG has a great demand in the market due to its medicinal effects, particularly in improving forest livelihoods and human health. Due to the significance of WSG, we conducted this research to explore the global research trends on WSG using systematic review methodology and keyword analysis. We used two international academic databases, the Web of Science and SCOPUS, to extract 115 peer-reviewed articles published from 1982 to 2020. The research subjects, target countries, and keywords were analyzed. Our results indicate four categories of WSG research subjects, namely growth conditions, components, effects on humans/animals, and the environment of WSG, and the case studies were mainly from the Republic of Korea, China, and the USA. Through topic modelling, research keywords were classified into five groups, namely medicinal effects, metabolite analysis, genetic diversity, cultivation conditions, and bioactive compounds. We observed that the research focus on WSG changed from the biological properties and cultivation conditions of WSG to the precise identification and characterization of bioactive metabolites of WSG. This change indicates an increased academic interest in the value-added utilization of WSG.

Promotion of in situ Forest Farmed American Ginseng (Panax quinquefolius L.) as a Sustainable Use Strategy: Opportunities and Challenges

The cultivation of wild-harvested plant species is one strategy to achieve species conservation while meeting continued demand. A limitation to this approach for species used in Traditional Chinese Medicine, however, is that products produced under ex situ artificial agricultural conditions are often not a perfect replacement for their wild-collected counterparts, so demand for wild-harvested materials persists. This situation applies to American ginseng, an internationally protected species by the Convention on International Trade of Endangered Species of Wild Fauna and Flora (CITES) since 1975. In this paper, we trace the trade the history and conservation need for American ginseng in North America, including a summary of the development and evolution of in and ex situ cultivation methods. We report results from a preliminary survey of product labeling of American ginseng sold online in China and adjacent regions and provide recommendations for promoting forest farmed ginseng to consumers as a sustainable use strategy. We suggest that the use of CITES’s new “human assisted” production category amongst trade partners, coupled with “green” product certification and e-commerce platforms, provides a new opportunity to encourage consumption of wild-cultivated rather than wild ginseng in east Asia, and the continued development of ginseng forest farming and supply transparency mechanisms in the eastern United States.

Prediction of the globally ecological suitability of Panax quinquefolius by the geographic information system for global medicinal plants (GMPGIS)

American ginseng (Panax quinquefolius L.) is a well-known Asian traditional herbal medicine with a large market demand. The plant is native to eastern North America, and its main producing areas worldwide are decreasing due to continuous cropping obstacles and environmental changes. Therefore, the identification of maximum similarities of new ecological distribution of P. quinquefolius, and prediction of its response to climate change in the future are necessary for plant introduction and cultivation. In this study, the areas with potential ecological suitability for P. quinquefolius were predicted using the geographic information system for global medicinal plants (GMPGIS) based on 476 occurrence points and 19 bioclimatic variables. The results indicate that the new ecologically suitable areas for P. quinquefolius are East Asia and the mid-eastern Europe, which are mainly distributed in China, Russia, Japan, Ukraine, Belarus, North Korean, South Korea, andRomania. Under global climate change scenarios, the suitable planting areas for P. quinquefolius would be increased by 9.16%-30.97%, and expandingnorth and west over the current ecologically suitable areas by 2070. The potential increased areas that are ecologically suitable include northern Canada, Eastern Europe, and the Lesser Khingan Mountains of China, and reduced regions are mainly in central China, the southern U.S., and southern Europe. Jackknife tests indicate that the precipitation of the warmest quarter was the important climatic factor controlling the distribution of P. quinquefolius. Our findings can be used as auseful guide for P. quinquefolius introduction and cultivation in ecologically suitable areas.

Sustainable Forest Management for Nontimber Products

Many of the plants and fungi that are harvested for nontimber products (e.g., foods, medicines, crafts) are critical to healthy forest ecosystems. These products also are essential to rural societies, contributing to the material and nonmaterial composition of communities and cultures. Product sales make important contributions at all economic scales, from household to national economies. Nontimber forest products (NTFPs) have been harvested for generations, sometimes centuries, yet they are seldom integrated into forest management. Few methods exist for inventory and assessment, and there is little evidence that harvests are sustainable. This article examines three elements of sustainable forest management for nontimber products: sociocultural, economic, and ecological, and elaborates with detailed examples of edible and medicinal species from United States (U.S.) forests. We synthesize the state of knowledge and emerging issues, and identify research priorities that are needed to advance sustainable management of NTFPs in the United States. Despite their social, economic, and ecological values, many of these species and resources are threatened by the overuse and lack of management and market integration. Sustainable management for nontimber products is attainable, but much research and development is needed to ensure the long-term sustainability of these resources and their cultural values, and to realize their economic potentials.

American Ginseng (Panax quinquefolium L.) as a Source of Bioactive Phytochemicals with Pro-Health Properties

Panax quinquefolium L. (American Ginseng, AG) is an herb characteristic for regions of North America and Asia. Due to its beneficial properties it has been extensively investigated for decades. Nowadays, it is one of the most commonly applied medical herbs worldwide. Active compounds of AG are ginsenosides, saponins of the glycosides group that are abundant in roots, leaves, stem, and fruits of the plant. Ginsenosides are suggested to be primarily responsible for health-beneficial effects of AG. AG acts on the nervous system; it was reported to improve the cognitive function in a mouse model of Alzheimer's disease, display anxiolytic activity, and neuroprotective effects against neuronal damage resulting from ischemic stroke in animals, demonstrate anxiolytic activity, and induce neuroprotective effects against neuronal damage in ischemic stroke in animals. Administration of AG leads to inhibition of hypertrophy in heart failure by regulation of reactive oxygen species (ROS) in mice as well as depletion of cardiac contractile function in rats. It also has an anti-diabetic and anti-obesity potential as it increases insulin sensitivity and inhibits formation of adipose tissue. AG displays anti-cancer effect by induction of apoptosis of cancer cells and reducing local inflammation. It exerts antimicrobial effects against several pathogenic strains of bacteria. Therefore, AG presents a high potential to induce beneficial health effects in humans and should be further explored to formulate precise nutritional recommendations, as well as to assess its value in prevention and therapy of some disorders, including cancer.

NMR characterization of novel pyranoanthocyanins derived from the pulp of Panax quinquefolius L. (North American ginseng)

Three major pigments (one natural and two derived) were determined to be present in the berry pulp of Panax quinquefolius L. (North American ginseng). The first was a simple anthocyanin (pelargonidin 3-O-lathyroside) along with two novel pyranoanthocyanins, structurally similar to those recently discovered in Staghorn sumac. The three anthocyanins were structurally characterized using NMR (¹ H, gCOSY, gHSQC, gHMBC, TOCSY, ROESY, and ¹³ C DEPTq135) and High Resolution MS. All three anthocyanins had the disaccharide lathyrose (2-O-(β-D-xylopyranosyl)-β-D-galactopyranoside) attached at the 3-O position. In the tradition of naming novel anthocyanin aglycones based on botanical origin, the new pyranoanthocyanin aglycones have been given the common names Panaxidin A (pelaragonidin-4-vinylcatechol) and Panaxidin B (pelargonidin-4-vinylphenol). Copyright © 2015 Her Majesty the Queen in Right of Canada Magnetic Resonance in Chemistry © 2015 John Wiley & Sons, Ltd.

A slow opportunist: physiological and growth responses of an obligate understory plant to patch cut harvesting

Understory light environments change rapidly following timber harvest, and while many understory species utilize and benefit from the additional light, this response is not ubiquitous in shade-obligate species. I examined the effects of patch cut timber harvest on the physiology and growth of an obligate forest understory species to determine if disturbances via timber harvest are physiological stressors or whether such disturbances provide physiological benefits and growth increases in understory species. Forest canopy structure, along with photosynthesis, respiration, water use efficiency, stomatal conductance, and growth rates of American ginseng were quantified one summer before and two summers after patch cut timber harvest. Survival following timber harvest was lower than that observed at undisturbed populations; however, growth of survivors increased post-harvesting, with growth increasing as a function of canopy openness. Light response curves as well as photosynthesis and respiration rates indicated that plants were not well acclimated to higher light levels in the growing season after timber harvest, but rather to two growing seasons after harvest. Relative growth rate formed a positive linear relationship with maximum photosynthesis following timber harvest. My study suggests that ginseng is a "slow opportunist", because while it benefits from sudden light increases, acclimation lags at least one growing season behind canopy changes. American ginseng is surprisingly resilient in the face of a discrete environmental shift and may benefit from forest management strategies that mimic the natural disturbance regimes common in mature forests throughout its range.

Development of interspecies hybrids to increase ginseng biomass and ginsenoside yield

Interspecific hybrids between Panax ginseng and P. quinquefolius results in hybrid vigor and higher ginsenoside contents. Ginseng is one of the most important herbs with valued pharmaceutical effects contributing mainly by the presence of bioactive ginsenosides in the roots. However, ginseng industry is impeded largely by its biological properties, because ginseng plants are slow-growing perennial herbs with lower yield. To increase the ginseng yield and amounts of ginsenosides, we developed an effective ginseng production system using the F(1) progenies obtained from the interspecific reciprocal cross between two Panax species: P. ginseng and P. quinquefolius. Although hybrid plants show reduced male fertility, F(1) hybrids with the maternal origin either from P. ginseng or P. quinquefolius displayed heterosis; they had larger roots and higher contents of ginsenosides as compared with non-hybrid parental lines. Remarkably, the F(1) hybrids with the maternal origin of P. quinquefolius had much higher ginsenoside contents, especially ginsenoside Re and Rb1, than those with the maternal origin of P. ginseng. Additionally, non-targeted metabolomic profiling revealed a clear increase of a large number of primary and secondary metabolites including fatty acids, amino acids and ginsenosides in hybrid plants. To effectively identify the F(1) hybrids for the large-scale cultivation, we successfully developed a molecular marker detection system for discriminating F(1) reciprocal hybrids. In summary, this work provided a practical system for reciprocal hybrid ginseng production, which would facilitate the ginseng production in the future.

The chemoattractant potential of ginsenosides in the ginseng - Pythium irregulare pathosystem

Ginsenosides produced by ginseng (Panax quinquefolius L.) are mildly fungitoxic saponins; however, exposure of the ginseng root pathogen Pythium irregulare Buisman to ginsenosides enhances its growth in a dose dependent manner, leading to speculation that ginsenosides may function as chemoattractants and/or growth regulators in the context of the ginseng - P. irregulare pathosystem. In the present work, it was demonstrated that the treatment of ginseng plants with a relatively high dose of ginsenosides by dipping their roots into a solution of ginsenosides prior to planting results in delayed infection by P. irregulare in pot experiments, as monitored by non-invasive chlorophyll fluorescence imaging. In an attempt to determine whether this observation results from a protective effect of the ginsenosides, or from a modification of P. irregulare growth habit in response to ginsenosides present in the soil, standard in vitro disk diffusion assays were conducted. Here, exposure of P. irregulare to crude ginsenosides or pure ginsenoside Rb1, resulted in delayed hyphal progression, while enhancing aerial hyphae build-up around ginsenoside-treated disks. By contrast, assays with pure ginsenoside F2 resulted in clear zones of inhibition around treated disks. While it remains unclear whether ginsenosides act as chemoattractants for P. irregulare in vivo, the results here suggest that these saponins serve to alter the growth habit of this organism, both in vivo and in vitro.

Resource investigation of traditional medicinal plant Panax japonicus (T.Nees) C.A. Mey and its varieties in China

ETHNOPHARMACOLOGICAL RELEVANCE

Panax japonicus, the perennial herb in the Araliaceae family, was used as the natural medicinal herb by Chinese traditional doctors for more than thousand years. Its rhizome was mainly used as a tonic, anti-inflammatory and hemostatic agent in China. Most of the therapeutic effects of P. japonicus had been reported due to the presence of tetracyclic or pentacyclic triterpene saponins. Volatile oil, polysaccharides and amino acids had also been found in P. japonicus species and reported in the pharmacological functions.

AIM OF THE STUDY

A three-year survey was conducted to determine the current resource status of P. japonicus (T.Nees) C. A. Mey and its varieties (P. japonicus var. major (Burkill) C.Y.Wu & Feng and P. japonicus var. bipinnatifidus (Seem.) C.Y.Wu & Feng) in 10 provinces of southern and southwestern China.

METHODS AND RESULTS

Whole plants were sampled at 64 sites. Resource distribution, habitat type, morphological variation and market trend of them were studied and discussed. The natural resource in China is rarely available due to extensive exploitation and continual environment deterioration in recent decades, Abundance of P. japonicus was much lower than previous records, mainly found in Hubei, Sichuan, Guizhou and Yunnan province. Wild resources of P.japonicus var. major and P.japonicus var. bipinnatifidus were even scarcer, only found in Guizhou and Yunan province. Despite their dramatic rise of market trend, the artificial cultivation of them was still not fully developed in China, but progressed rapidly in Hubei province.

CONCLUSION

In this study, we synthesized our understandings of the current resource state of P. japonicus׳s existence, variation and cultivation in China. This study will aid further investigations and increased protection of these plants, which are very valuable to traditional herbal medicine.

Synergistic effects of climate change and harvest on extinction risk of American ginseng

Over the next century, the conservation of biodiversity will depend not only on our ability to understand the effect of climate change, but also on our capacity to predict how other factors interact with climate change to influence species viability. We used American ginseng (Panax quinquefolius L.), the United States' premier wild-harvested medicinal, as a model system to ask whether the effect of harvest on extinction risk depends on changing climatic conditions. We performed stochastic projections of viability response to an increase in maximum growing-season temperature of 1°C over the next 70 years by sampling matrices from long-term demographic studies of 12 populations (representing 75 population-years of data). In simulations that included harvest and climate change, extinction risk at the median population size (N = 140) was 65%, far exceeding the additive effects of the two factors (extinction risk = 8% and 6% for harvest and climate change, respectively; quasi-extinction threshold = 20). We performed a life table response experiment (LTRE) to determine underlying causes of the effect of warming and harvest on deterministic λ (λd). Together, these factors decreased λd values primarily by reducing growth of juvenile and small adult plants to the large-adult stage, as well as decreasing stasis of the juveniles and large adults. The interaction observed in stochastic model results followed from a nonlinear increase in extinction risk as the combined impact of harvest and warming consistently reduced λ values below the demographic tipping point of λ = 1. While further research is needed to create specific recommendations, these findings indicate that ginseng harvest regulations should be revised to account for changing climate. Given the possibility of nonlinear response like that reported here, pre-emptive adaptation of management strategies may increase efficacy of biodiversity conservation by allowing behavior modification prior to precipitous population decline.