Phenylpropenoid content in high-altitude cultivated Rhodiola rosea L. provenances according to plant part, harvest season and age

Individual Differences in Growth and in Accumulation of Secondary Metabolites in Rhodiola rosea Cultivated in Western Siberia

In this study, growth parameters of underground parts and concentrations of phenylpropanoids, phenylethanoids, flavonoids, hydroxybenzoic acids, and catechins in aqueous-ethanol extracts of 6-year-old cultivated plants of Rhodiola rosea (propagated in vitro) of Altai Mountain origin were analyzed, and differences in chemical composition among plant specimens and between plant parts (rhizome and root) were evaluated. High-performance liquid chromatography detected 13 phenolic compounds. Roots contained 1.28 times higher phenylethanoids levels (1273.72 mg/100 g) than rhizomes did. Overall, the concentration of phenylethanoids in underground organs was not high and ranged from 21.36 to 103.00 mg/100 g. High variation among R. rosea individual plants was noted both in growth characteristics and in levels of secondary metabolites under our cultivation conditions. It was found that concentrations of phenylpropanoids, phenylethanoids, and catechins significantly depend on the plant part analyzed (p ≤ 0.05). Specimen No. 4 is characterized by the highest concentration of rosavins (1230.99 mg/plant) and the lowest concentration of cinnamyl alcohol (62.87 mg/plant). Despite the wide range of values, all 10 tested specimens (underground part) met the minimum requirements of the United States Pharmacopeia (2015) for rosavins (0.3%) and of the Russia State Pharmacopoeia (2015) for the average level of rosavins (roots): (1%).

Pharmaceutical Potential of High-Altitude Plants for Fatigue-Related Disorders: A Review

Natural plants from plateaus have been the richest source of secondary metabolites extensively used in traditional and modern health care systems. They were submitted to years of natural selection, co-evolved within that habitat, and show significant anti-fatigue-related pharmacological effects. However, currently, no review on high-altitude plants with anti-fatigue related properties has been published yet. This study summarized several Chinese traditional high-altitude plants, including Rhodiola rosea L., Crocus sativus L., Lepidium meyenii W., Hippophaerhamnoides L., which are widely used in the Qinghai–Tibet Plateau and surrounding mountains, as well as herbal markets in the plains. Based on phytopharmacology studies, deeper questions can be further revealed regarding how these plants regulate fatigue and related mental or physical disease conditions. Many active derivatives in high-altitude medical plants show therapeutic potential for the management of fatigue and related disorders. Therefore, high-altitude plants significantly relieve central or peripheral fatigue by acting as neuroprotective agents, energy supplements, metabolism regulators, antioxidant, and inflammatory response inhibitors. Their applications on the highland or flatland and prospects in natural medicine are further forecast, which may open treatments to reduce or prevent fatigue-related disorders in populations with sub-optimal health.

Current state of populations of Rhodiola rosea L. (Crassulaceae) in East Kazakhstan

BACKGROUND

Based on world experience, first, a modern assessment of the flora is needed to develop strategies for the conservation of ecosystems of rare and endangered plant species. A regional and global biodiversity strategy should focus on assessing the current state of bioresources. To preserve the biodiversity of the species and its habitat, we evaluated botanical features, ontogenetic phases, the ecological and phytocenotic structure of the rare and endangered of Rhodiola rosea L. (golden rose root) populations from the highlands of Eastern Kazakhstan.

RESULTS

R. rosea in the study region lives on damp mossy rocks, rocky slopes, overgrown moraines and along the banks of mountain rivers in the upper limit of cedar-larch forests, subalpine and alpine belts, in the altitude limit of 1700-2400 m. In the studied region, R. rosea begins to vegetate in May-June, blooms in June-July, the fruits ripen in August. The species is encountered in the high mountain ranges of the Kazakh Altai and Saur-Tarabagatai. Unfavorable habitat conditions for the species are overgrown by sedge-grass and birch-moss communities. The most common species at sites with R. rosea are: Schulzia crinita, Achillea ledebourii, Doronicum altaicum, Macropodium nivale, Hylotelephium telephium, Rhodiola algida, Carex capillaris, C. aterrima. Ontogenetic study revealed that all age-related phases were present, with the exception of the senile states. Individual life expectancy shown to be 50-55 years. The analysis of the species composition in the communities with R. rosea showed that the leading families in terms of the number of accompanying species are Poaceae, Ranunculaceae, Asteraceae, Rosaceae and Caryophyllaceae, Apiaceae, Fabaceae; while the most dominant genera are: Carex, Aconitum, Dracocephalum, Festuca, Pedicularis, Poa, Salix; the ecological groups are dominated by psychrophytes, mesophytes mesopsychrophytes; the Asian, Eurasian, and Holarctic groups are the most represented groups. Dominant life forms according to Serebyakov were rod-rooted, brush-rooted, short-rooted and long-rooted grasses, while based on Raunkiaer's groups the overwhelming majority consisted of Hemincryptophytes (74%).

CONCLUSIONS

The R. rosea populations of Kazakhstan represent an important gene stock of the species. Our study provides new insights into the species' biology thus contributes to the conservation of biodiversity on a wide spatial scale.

Rhodiola rosea Rhizome Extract-Mediated Green Synthesis of Silver Nanoparticles and Evaluation of Their Potential Antioxidant and Catalytic Reduction Activities

The silver nanoparticles (AgNPs) using the rhizome extract of Rhodiola rosea have been reported. However, their antioxidant activity and whether the biogenic AgNPs could be used to catalyze the reduction of hazardous dye or used as fluorescence enhancers are unknown. This study focused on the facile green synthesis of silver nanoparticles using the rhizome aqueous extract of R. rosea (G-AgNPs). We then studied their antioxidant activity and catalytic degradation of hazardous dye Direct Orange 26 (DO26) and Direct Blue 15 (DB15). Their effects on fluorescein's fluorescent properties were also evaluated. The chemical AgNPs (C-AgNPs) were synthesized by reducing solid sodium borohydride (NaBH₄), and its above activities were compared with those of G-AgNPs. The formation of G-AgNPs was confirmed by the appearance of brownish-gray color and the surface plasmon resonance (SPR) peak at 437 nm. The biogenic AgNPs were approximately 10 nm in size with a regular spherical shape identified from transmission electron microscopy (TEM) analysis. G-AgNPs exhibited significantly improved 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity than butylated hydroxytoluene (BHT) and C-AgNPs (p < 0.05). The biogenic G-AgNPs were also found to function as an effective green catalyst in reducing DO26 and DB15 by NaBH₄, which is superior to C-AgNPs. Furthermore, G-AgNPs showed better fluorescence enhancement activity than C-AgNPs, and the concentration required was lower. When the concentration of the G-AgNP solution was 64 nmol/L, the fluorescence intensity reached the maximum of 5460, with the fluorescence enhancement efficiency of 3.39, and the fluorescence activity was stable within 48 h. This study shows the efficacy of biogenic AgNPs in catalyzing the reduction of hazardous dye DO26 and DB15. Biogenic AgNPs could also be used as fluorescence enhancers in low concentrations.

Running out of time to smell the roseroots: Reviewing threats and trade in wild Rhodiola rosea L

ETHNOPHARMACOLOGICAL RELEVANCE

Rhodiola rosea L. has a circumpolar distribution and is used in ethnomedicines of Arctic peoples, as well as in national systems of traditional medicine. Since the late 20th century, global demand for R. rosea has increased steadily, in part due to clinical research supporting new uses in modern phytotherapy. Global supply has been largely obtained from wild populations, which face threats from poorly regulated and destructive exploitation of the rootstocks on an industrial scale.

AIM OF THE STUDY

To evaluate (i) the conservation status, harvesting and trade levels of R. rosea, in order to determine whether international trade should be monitored, (ii) the current state of experimental and commercial farming and whether cultivation may play a role to take pressure off wild stocks, and (iii) evidence of substitution of other Rhodiola species for R. rosea as an indicator of overexploitation and rarity.

MATERIALS AND METHODS

We reviewed published studies on R. rosea biology and ecology, as well as information on impacts of wild harvest, on management measures at the national and regional levels, and on the current level of cultivation from across the geographic range of this species. Production and trade data were assessed and analysed from published reports and trade databases, consultations with R. rosea farmers, processors of extracts, and trade experts, but also from government and news reports of illegal harvesting and smuggling.

RESULTS AND CONCLUSIONS

Our assessment of historical and current data from multiple disciplines shows that future monitoring and protection of R. rosea populations is of time-sensitive importance to the fields of ethnobotany, ethnopharmacology, phytochemistry and phytomedicine. We found that the global demand for R. rosea ingredients and products has been increasing in the 21st century, while wild populations in the main commercial harvesting areas continue to decrease, with conservation issues and reduced supply in some cases. The level of illegal harvesting in protected areas and cross border smuggling is increasing annually coupled with increasing incidences of adulteration and substitution of R. rosea with other wild Rhodiola species, potentially negatively impacting the conservation status of their wild populations, but also an indicator of scarcity of the genuine article. The current data suggests that the historical primary reliance on sourcing from wild populations of R. rosea should transition towards increased sourcing of R. rosea from farms that are implementing conservation oriented sustainable agricultural methods, and that sustainable wild collection standards must be implemented for sourcing from wild populations.

Authenticity and quality evaluation of different Rhodiola species and commercial products based on NMR-spectroscopy and HPLC

INTRODUCTION

The main concern regarding the authenticity and quality of Rhodiola rosea L. (Sedum rosea (L.) Scop.) products is their adulteration with other Rhodiola species.

OBJECTIVE

The aim of the study was the development of a reliable and practical analytical platform for quality and quantity assessment of the characteristic molecules in three Rhodiola species (R. rosea, R. kirilowii (Regel) Maxim and R. crenulata (Hook. f. & Thomson) H. Ohba), commercial products and their possible application as markers for the authentication of R. rosea based products.

MATERIAL AND METHODS

The major molecules were identified by one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR)-based metabolomics and quantitatively determined by high-performance liquid chromatography ultraviolet (HPLC-UV) analysis. The orthogonal projections to latent structures discriminant analysis (OPLS-DA) revealed the specific patterns in the metabolite profiles of R. rosea and R. crenulata.

RESULTS

The coumarin crenulatin was only identified in R. crenulata and can be used as a marker to detect potential adulteration of the commercial products. Crenulatin was identified in two of the four analysed products by NMR-spectroscopy. According to the HPLC data, in less than a quarter of all products, the labelled amounts of salidroside and total rosavins were confirmed.

CONCLUSIONS

The developed analytical platform was found to be useful in the investigations of the phytochemical diversity of different Rhodiola species, the recognition of the unique metabolites between them and the identification of adulterated products. Therefore, this approach could be applied from the earliest to the latest stages of the value chain in the manufacturing of R. rosea based products.

Variability of Major Phenyletanes and Phenylpropanoids in 16-Year-Old Rhodiola rosea L. Clones in Norway

Rhodiola rosea L. (roseroot) is an adaptogen plant belonging to the Crassulaceae family. The broad spectrum of biological activity of R. rosea is attributed to its major phenyletanes and phenylpropanoids: rosavin, salidroside, rosin, cinnamyl alcohol, and tyrosol. In this study, we compared the content of phenyletanes and phenylpropanoids in rhizomes of R. rosea from the Norwegian germplasm collection collected in 2004 and in 2017. In general, the content of these bioactive compounds in 2017 was significantly higher than that observed in 2004. The freeze-drying method increased the concentration of all phenyletanes and phenylpropanoids in rhizomes compared with conventional drying at 70 °C. As far as we know, the content of salidroside (51.0 mg g⁻¹) observed in this study is the highest ever detected in Rhodiola spp. Long-term vegetative propagation and high genetic diversity of R. rosea together with the freeze-drying method may have led to the high content of the bioactive compounds observed in the current study.

There "ain't no mountain high enough"?: The drivers, diversity and sustainability of China's Rhodiola trade

ETHNOPHARMACOLOGICAL RELEVANCE

Across Asia, Rhodiola species have been used in Bhutanese, Mongolian, Nepalese, Kazakh, Kyrgyz and Uzbek traditional medical systems. China is globally significant in terms of Rhodiola species diversity, with over 60% (55 species) of the world's 90 Rhodiola species, including 16 species found nowhere else in the world. Since the late 1980's there has been a shift from relatively low demand for infusions using chopped dried Rhodiola roots, to high 21st century demand for a wide variety of processed products. China's trade in Rhodiola products is now very diverse, with use in cosmetics and foods in addition to herbal products. Rhodiola crenulata (Hook.f. & Thomson) H.Ohba is the most widely traded species in China. In addition to R. crenulata and Rhodiola rosea L., 19 Rhodiola other species are used.

AIMS OF THE STUDY

These were to: (i) better understand why adulteration occurs in Rhodiola products; (ii) become more aware of what drives the growing market demand for Rhodiola products in China; (iii) find out whether increased demand is reflected in wholesale prices for Rhodiola raw materials traditional medicine markets; (iv) to examine Rhodiola supply chains and (v) given that wild populations are the primary supply source, to review the implications of growing demand for conservation and sustainable use.

MATERIALS AND METHODS

Firstly, we assessed growth in the diversity of Rhodiola products using three approaches: (i) by assessing patent applications for Rhodiola products in China (1990-2019); (ii) in 2018, through on-line searches of CFDA (China Food and Drug Administration) records for medicines and dietary supplements that had Rhodiola as an ingredient and (iii) by visiting retail stores in 2018 and 2019 to assess the diversity of commercial Rhodiola based products in trade. Secondly, we visited traditional medicine markets in Yunnan, Sichuan, and Qinghai provinces to investigate the trade in Rhodiola (folk taxonomy, trade names, prices, source areas, levels of processing and grading). Thirdly, we analysed the wholesale price data for Rhodiola raw materials in trade over a 16-year period (2002-2018). Fourthly, as most products come from wild collected Rhodiola species, we documented the extent of Rhodiola cultivation in China.

RESULTS

International exports of Rhodiola products from China, particularly extracts, is a major driver of commercial trade. One proxy indicator of Rhodiola product diversification in China has been the rapid rise in patent applications from single applications in 1990 and 1991, to a peak of 1017 patent applications in 2015. Wholesale price data from 2002 to 2018 shows a steady increase in wholesale prices. As the growing market for Rhodiola products in China is currently supplied entirely from wild collection, there are justifiable concerns about sustainability. Commercial cultivation needs to expand to meet future demand.

CONCLUSIONS

In contrast to Europe and North America, where R. rosea is the focal species in commerce, the trade in Rhodiola products in China is much more diverse. In the face of growing demand, both effective conservation of wild populations and cultivation are needed.

Rhodiosin and herbacetin in Rhodiola rosea preparations: additional markers for quality control?

Context:Rhodiola rosea L. (Crassulaceae) is well-known to contain flavonoids such as the herbacetin derivative rhodiosin. However, flavonoids are not typically used in quality control.

Objective: This study analyses two flavonoids of R. rosea rhizomes and roots for their potential as analytical markers.

Materials and methods: Two constituents were isolated from ethanolic extracts via HPLC, identified via NMR and quantified via RP-HPLC. Presence and content variation was investigated according to extraction (solvent and repetitions), drying (temperature and duration) and sample origin (homogenously cultivated plants of different provenance, commercial samples).

Results: Rhodiosin was identified as a main flavonoid, accompanied by 10-fold lower concentrated herbacetin. Both compounds were best extracted with 70–90% ethanol, but were also detectable in more aqueous extracts. Different drying conditions had no effect on the flavonoid content. These two flavonoids were consistently identified in rhizome and root extracts of over 100 R. rosea samples. Rhizomes tend to contain less flavonoids, with average ratios of rosavins to flavonoids of 1.4 (rhizomes) and 0.4 (roots). Provenance differences were detected in the range (rhodiosin plus herbacetin) of 760–6300 µg/mL extract corresponding to a maximum of approximately 0.5–4.2% (w/w) in the dry drug.

Conclusions: For the first time, two main flavonoids present in R. rosea were quantified systematically. Rhodiosin and herbacetin can be detected simultaneously to phenylpropenoids or salidroside in authentic samples, influenced by the plant part examined and the plant origin. Rhodiosin and herbacetin may serve as additional marker to guarantee a consistent content of R. rosea products.

Growth and Physiological Responses of Adenophora triphylla (Thunb.) A.DC. Plug Seedlings to Day and Night Temperature Regimes

Adenophora triphylla (Thunb.) A.DC., three-leaf lady bell, is an important medicinal plant used against cancers and obesity. It has been well-established that the temperature regime affects plant growth and development in many ways. However, there is no study available correlating the growth of A. triphylla seedlings with different day and night temperature regimes. In order to find an optimal temperature regime, growth and physiology were investigated in A. triphylla plug seedlings grown in environment-controlled chambers at different day and night temperatures: 20/20 °C (day/night) (TA), 25/15 °C (TB), and 20/15 °C (TC). The seedlings in plug trays were grown under a light intensity of 150 μmol·m−2·s−1 PPFD (photosynthetic photon flux density) provided by white LEDs, a 70% relative humidity, and a 16 h (day)/8 h (night) photoperiod for six weeks. The results showed that the stem diameter, number of roots, and biomass were significantly larger for seedlings in TB than those in TA or TC. Moreover, the contents of total flavonoid, total phenol, and soluble sugar in seedlings grown in TB were markedly higher than those in seedlings in the other two treatments. Soluble protein content was the lowest in seedlings in TC, while starch content was the lowest in seedlings grown in TA. Furthermore, seedlings grown in TB showed significantly lower activities of antioxidant enzymes such as superoxide dismutase, catalase, ascorbate peroxidase, and guaiacol peroxidase. Native PAGE (polyacrylamide gel electrophoresis) analysis further proved low activities of antioxidant isozymes in TB treatment. Meanwhile, the lowest content of hydrogen peroxide was observed in seedlings grown in TB. In conclusion, the results suggested that the 25/15 °C (day/night) temperature regime is the most suitable for the growth and physiological development of A. triphylla seedlings.