Ethnopharmacology, Phytochemistry, and Pharmacology of the Genus Glehnia: A Systematic Review

Glehnia littoralis Fr. Schmidt ex Miq, the sole species in the genus Glehnia (Apiaceae), has long been used in traditional Chinese medicine to treat fatigue, weakness, stomach-yin deficiency, lung heat, cough, dry throat, and thirst. Recently, G. littoralis has also been incorporated into a wide range of Chinese vegetarian cuisines. Based on the comprehensive information, advances in botany, known uses, phytochemistry, pharmacology, and toxicity of G. littoralis, we aim to highlight research gaps and challenges in studying G. littoralis as well as to explore its potential use in plant biotechnology. This may provide more efficient therapeutic agents and health products from G. littoralis. A literature search of SciFinder, ScienceDirect, Scopus, TPL, Google Scholar, Baidu Scholar, and Web of Science, books, PhD and MSc dissertations, and peer-reviewed papers on G. littoralis research was conducted and comprehensively analyzed. We confirmed that the ethnomedical uses of G. littoralis have been recorded in China, Japan, and Korea for thousands of years. A phytochemical investigation revealed that the primary active compounds were phenylpropanoids, coumarins, lignanoids, and flavonoids, organic acids and derivatives, terpenoids, polyacetylenes, steroids, nitrogen compounds, and others. Our analysis also confirmed that the extracts of G. littoralis possess immunoregulatory, antitumor, anti-inflammatory, hepatoprotective, antioxidant, neuroprotective, antibacterial, antifungal, and analgesic properties. Although further studies are required, there is strong evidence of the antitumor and immunoregulatory potential of G. littoralis. Also, more studies are needed to elucidate the mechanisms of action of its active compounds (e.g., falcarinol and panaxydiol) before any clinical studies can be carried out.


Introduction
e genus Glehnia belongs to the Apiaceae family and contains only one species, Glehnia littoralis Fr. Schmidt ex Miq. G. littoralis is a perennial herb with the property of salt tolerance, which allows it to grow on the seashores of Northern Pacific countries, particularly China, Japan, Korea, the USSR, Canada, and the USA [1].
G. littoralis has been used in traditional medicine as tonic, antipyretic, and analgesic for thousands of years [2].

Phytochemistry
According to the literature, the chemical composition isolated from G. littoralis consists primarily of phenylpropanoids, coumarins, lignans, flavonoids, organic acids, terpenoids, polyacetylenes, and steroids. In addition, G. littoralis also contains volatile oils, polysaccharides, and polyols. National scholars generally used high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), 13 C-magnetic resonance, hydrogenmagnetic resonance, and column chromatography to separate and identify these complex chemical constituents. Table 2 shows the chemical constituents found in G. littoralis, including chemical composition names and its classes, material distribution, and appropriate citations for this species.

Phenylpropanoids.
Phenylpropanoids widely exist in nature, including most of the natural aromatic compounds. As a major secondary metabolite in G. littoralis, phenylpropanoids possess various pharmacological effects including immune regulation, antibacterial, antiinflammatory, and antioxidative properties. So far, ten phenylpropanoids, including six phenylpropionic acid (1)(2)(3)(4)(5)10), three phenylpropanal (6)(7)(8), and one phenylpropanol (9) were isolated from G. littoralis. Furthermore, Zhang et al. isolated and identified two simple phenyllactic acid compounds (S)-phenyllactic acid (1) and (S)-phenyllactic acid methyl ester (2) via spectral analysis of ethanol extract from the root of G. littoralis [19]. It is worth noting that these compounds were isolated from the plant for the second time when studying their taxonomic significance, suggesting that these compounds may be useful chemical taxonomic markers for G. littoralis. In addition, Yuan et al. analyzed the ethyl acetate fraction of G. littoralis and obtained a phenylpropanoid compound with a unique biphenyl ferulate structure, which was identified through spectroscopy as glehnilate (10) [45]. e chemical structures of phenylpropanoids isolated from G. littoralis are presented in Figure 2.
Kitajima et al. separated the methanol extracts from the roots and rhizomes of G. littoralis using various column chromatography techniques (Sephadex LH-20, silica gel, and Lobar RP-8) and identified them via FAB-MS, 1 H-NMR, 13 C-NMR, and HMBC spectrum, allowing for the identification of five monoterpenoids, namely, (-)-angelicoidenol 2-  ese compounds can be used as important markers to evaluate the quality of G. littoralis [19,67].

Steroids.
Steroids are nearly ubiquitous in plants and have attracted increasing attention due to their diverse activities. Phytosterols are also important raw materials for the production of steroids and vitamin D3, which are used for the prevention and treatment of coronary atherosclerotic heart disease, and have obvious curative effects on ulcers, skin squamous cell carcinoma, and cervical cancer [59].
Two steroids were isolated from the petroleum ether fraction of methanol extract of the dried root of G. littoralis by Zhang et al.: β-sitosterol (133) and daucosterol (134). And they found that compound 134 was obtained from G. littoralis for the first time [59]. Dong et al. also isolated two steroids, stigmasterol (135) and cerevisterol (136) from dried roots of three-year-old G. littoralis, and identified their structure by 1 H-NMR and 13 C-NMR [65]. Further, through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, they determined that compound 135 is capable of inhibiting SGC-7901 and HEP-G2 in vivo, and compound 136 was firstly isolated from G. littoralis. e chemical structures of steroids isolated from G. littoralis are presented in Figure 11.

Nitrogen
Compounds. Nitrogen compounds are indispensable to living organisms. In recent years, researchers have studied nine nitrogen compounds in G. littoralis. eir structures are shown in Figure 12.
e EtOAc fraction of the extraction from G. littoralis was chromatographed on a silica gel column to give two nitrogen compounds including uridine (140) and adenosine (141), which were identified by means of comparison with published data or with authentic samples [39]. Furthermore, Zhao and Yuan isolated 5′-methylthioadenosine (144) and L-tryptophan (145) from G. littoralis by the method of Sephadex LH-20, and the compound 144 was firstly obtained from G. littoralis [72].    that the contents of potassium, sodium, and phosphorus in peeled root samples of G. littoralis were significantly lower than those in nonpeeled root samples, which verified the enrichment of specific elements by root and root bark. e chemical structures of other chemical constituents isolated from G. littoralis are presented in Figure 13. Yang et al. (2012) studied the effect of supercritical fluid extraction of carbon dioxide (SFE-CO 2 ) extract from G. littoralis on T lymphocyte subpopulation induced by cytoxan (CTX) in immunosuppressed C57BL/6J mice. A globulimeter was used to detect WBC, RBC, and PLT, and the absolute number of T lymphocyte subpopulations was calculated by flow cytometry. e results showed that SFE-CO 2 extract from G. littoralis increased the number of total CD3 + T cells as well as CD3 + , CD4 + T cells, and CD3 + , CD8 + T cells in the peripheral blood of immunosuppressed C57BL/6J mice (P < 0.05). However, no significant differences were observed in the ratio of CD3 + CD4 + /CD3 + CD8 + T cells between the group treated with low doses of SFE-CO 2 extract and the control group (P > 0.05), indicating that the low-dose SFE-CO 2 extract restored the CD3 + CD4 + /CD3 + CD8 + T-cell ratio in immunosuppressed mice to the normal level. e SFE-CO 2 extract of G. littoralis Schmidt had a significant recovery effect on the peripheral immune system of immunosuppressed C57BL/6J mice [78].

Immunoregulatory Activities.
Rong et al. prepared a mouse model of hyperthyroidism yin deficiency by administration of thyroxine and reserpine to mice, and the immunoregulation effect of the polysaccharide of Glehniae Radix (GLP) was applied to study weight fluctuation. e cytotoxic activity of NK cells, the T lymphocyte transformation function in the spleen, and the content of serum anti-sheep red blood cell antibodies IgM and IgG in yin deficiency mice were separately determined by MTT assays and indirect enzyme-linked immunosorbent assays.
e results showed that GLP increased weight (P < 0.01, P < 0.05), significantly enhanced the killing activity of NK cells (P < 0.05) and T lymphocyte transformation function (P < 0.05), and increased the level of serum IgM and IgG antibodies (P < 0.05). It was suggested that GLP has the effect of nourishing yin and tonifying deficiency and could enhance the function of specific and nonspecific immunity [79].   Evidence-Based Complementary and Alternative Medicine for 8 days. e blank control group, model control group, and American ginseng capsule 1.56 g·kg − 1 group were intragastrically administered at the same time. e effects of cyclophosphamide on the phagocytic index of peripheral blood leukocytes, thymus gland, and spleen indices of mice were compared after the last administration. e results showed that the thymic index and spleen index of mice in the high-dose alcohol extract group were significantly increased, which suggests that the stem and leaf of Panax quinquefolium may inhibit the decrease in leukocyte count and thymic index in peripheral blood of mice induced by cyclophosphamide and enhance the phagocytic function of reticular endothelial system in immunocompromised mice [80]. e three extractions, E1 (dissolved matter only in water), E2 (dissolved matter only in alcohol), and E3 (dissolved matter in water and alcohol, which was obtained by water from roots of G. littoralis and treated with alcohol), had in vitro pharmacological effect on lung cancer cell line (A549), stomach cancer cell line (SGC), and liver cancer cell line (HEP). e results showed that the different concentrations of the three extractions had certain inhibitory effect on liver cancer cell line (HEP) in vitro. ere was no significant difference between the concentrations of E1 and E3. e inhibition rate of E2 was significantly higher than other two extractions when the concentrations at 300 μg·mL − 1 . Most concentrations of the three extractions had anticancer activities against lung cancer cell line (A549). When the concentration of E3 was 37.5 μg·mL − 1 , its inhibitory rate was significantly higher than that of the other two extractions. ere was no significant difference among different concentrations of E1. When the two concentrations of E2 were 75 and 18.750 μg·mL − 1 , their inhibitory rates were significantly higher than those of the other two extractions. e only concentration that had anticancer activities on stomach cancer cell line (SGC) was E2 at 300 μg·mL − 1 , and its inhibitory rate was only 6.34% [82].

Antitumor
Um et al. found that the crude extract and the solventpartitioned fractions (n-hexane, 85% MeOH, n-butanol, and water) of G. littoralis had significant synergistic inhibitory effect on the proliferation of HT-29 human colon cancer cells. e inhibitory rates of 50 μg·mL − 1 extract of G. littoralis on human colon cancer cells were 12%, 76%, 41%, 77%, and 86%, respectively, and the inhibitory effects were dose-dependent [69]. Dong et al. studied the anticancer activity of bergapten from G. littoralis extract. at study showed that 100 mg·L − 1 bergapten had inhibitory effect on SGC-7901 and HEP-G2 gastric cancer cell lines [65].

Anti-Inflammatory Activities.
e anti-inflammatory activities of methylene chloride fraction from G. littoralis extract (MCF-GLE) were studied by . MCF-GLE strongly inhibited the release of nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) and significantly inhibited the mRNA and protein expression of inducible nitric oxide synthase and cyclooxygenase-2 (COX-2) in the RAW 264.7 macrophage cells by lipopolysaccharide stimulation in a dose-dependent manner. In addition, MCF-GLE inhibited nuclear factor kappa-B (NF-κB) activation. e MCF-GLE also reduced the activation of extracellular signalregulated kinase (ERK) and Jun kinase (JNK) in a dosedependent manner. e anti-inflammatory properties of MCF-GLE were carried out by inhibiting the mRNA and protein expression of inducible nitric oxide synthase (iNOS) and COX-2, the expression of NO, PGE2, TNF-α and IL-1β in LPS-induced 264.7 macrophages cells.
is study also found that the anti-inflammatory activity of MCF-GLE was mediated by inhibition of IXB-A phosphorylation, nuclear translocation of NF-κB P65 subunit, and activation of MAPK (ERK and JNK) [2]. e effect of 70% ethanolic extract from G. littoralis (GLE) on inflammatory skin in mice was also studied by . Ear edema was induced by administering 12-O-tetradecanoyl-phorbol-13-acetate (TPA). e activities of IL-1, TNF-α, and myeloperoxidase (MPO), and histology in acute and chronic skin tissues were detected. At the same time, the vascular permeability test induced by acetic acid was carried out. 200 mg·kg − 1 GLE significantly inhibited the topical edema of mouse ear, which led to a significant decrease in skin thickness, tissue weight, Evidence-Based Complementary and Alternative Medicine production of inflammatory cytokines, and activity of MPO mediated by neutrophils and polymorphonuclear leukocytes. In addition, GLE decreased significantly within the inflammatory site induced by chronic TPA and significantly inhibited vascular permeability induced by acetic acid in mice [83].
Other studies investigated the anti-inflammatory effect of imperatorin isolated from the root of G. littoralis. A mouse paw edema model was induced by lipopolysaccharide-(LPS-) stimulated mouse RAW264.7 macrophage cells and a carrageenan-(Carr-) induced mouse paw edema model. When RAW264.7 macrophages were treated with imperatorin together with LPS, the production of NO was significantly inhibited in a concentration-dependent manner. Western blotting showed that, in the LPS-induced RAW 264. 7

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Evidence-Based Complementary and Alternative Medicine blocked by imperatorin. At 4 h and 5 h after CARR administration, procyanidin decreased paw edema and the level of MDA and increased the activities of CAT, SOD, and GPX in paw edema. e Carr-induced iNOS and COX-2 expressions were also decreased, as well as the infiltration of neutrophils into the inflammatory site. Moreover, it could decrease the NO and tumor necrosis factor and prostaglandin E2 levels in serum [84].

Hepatoprotective Activities.
Jin et al. observed the effect of the ethanol extract of G. littoralis (EEAR) on acute liver injury induced by CCl 4 in rats. SD rats were divided into control group, CCl 4 group, 150 mg·kg − 1 EEAR + CCl 4 group, 300 mg·kg − 1 EEAR + CCl 4 group, and 50 mg·kg − 1 silibinin + CCl 4 group, and the treatment was daily carried out with 0.5 mL extract by gastric administration for 7 days. e control group was injected intraperitoneally with saline, while the other groups were injected intraperitoneally with CCl 4 (1 mL·kg − 1 ) in the last day. And the levels of alanine aminotransferase (ALT), aminotransferase (AST), and alkaline phosphatase (ALP) in the serum were detected. e activities of superoxide dismutase (SOD) and catalase (CAT) and the level of malondialdehyde (MDA) of the liver homogenate were, respectively, detected by the yellow-terin oxidase method and the thiobarbituric acid method. Compared with the control group, the levels of ALT, AST, and ALP in the serum of CCl 4 group were significantly increased (P < 0.05). Compared with CCl 4 group, the content of AIT, AST, and ALP in the serum of the EEAR + CCl 4 group decreased significantly (P < 0.05), the degree of HE staining was light, the activity of SOD and CAT in the cytoplasm was increased, and the level of MDA was decreased (P < 0.05). EEAR may significantly reduce inflammatory hepatocytes, improve steatosis of hepatocytes, and increase the number of normal hepatocytes [85].
Ultrastructural changes and apoptosis of tissue cells are the main manifestations of liver aging. e combined use of the root of G. littoralis, Radix Polygoni Multiflori, and Radix Salviae Miltiorrhizae in rats with liver diseases showed that these three Chinese medicines can not only significantly increase the level of IL-2 in serum, but also restore the volume of liver cells to the normal range, with homogenous nuclear chromatin. e number and morphology of mitochondria and rough endoplasmic reticulum returned to the normal range. e results indicated that the root of G. littoralis, Radix Polygoni Multiflori, and Radix Salviae Miltiorrhizae can be used to enhance the body's immunity, improve the ultrastructure of hepatocytes, inhibit the apoptosis of hepatocytes, and thus achieve antiaging purposes [86].

Antioxidant Activities.
Oxidative stress is defined as the imbalance between the increase in reactive oxygen species concentration and the low activity of antioxidant mechanism. An increase in oxidative stress can result in damage to cellular structures, possibly damaging the tissues [87]. In a study examining the antioxidant ability of Shashen Maidong Decoction in a chronic bronchitis rat model, pharmacodynamic experiments were conducted by examining the activity of SOD, CAT, glutathione peroxidase (GSH-PX), and MDA as indices. e results showed that Shashen Maidong Decoction (with G. littoralis as the main component) increased the activity of SOD, CAT, and GSH-PX and decreased the MDA content in the serum of rats with chronic bronchitis [88]. An additional study showed that both the aqueous and organic extracts (500 μg·mL − 1 ) of G. littoralis have antioxidant properties. e aqueous extract of G. littoralis exhibited a strong inhibitory effect on hemolysis of rat erythrocytes. And the organic extract of the herb showed strong inhibition of lipid peroxidation in brain homogenates [89]. In the evaluation of microwave-assisted extraction of polysaccharides from G. littoralis, the herb exhibited high scavenging activity against 2,2-diphenyl-1picryl-hydrazyl-hydrate (DPPH), hydroxyl, and superoxide anion radicals [90].

Neuroprotective Activities. Park et al. subjected gerbils
to transient global cerebral ischemia for 5 min. e extract of G. littoralis (GLE; 100 and 200 mg·kg − 1 ) was taken once a day before conducting ischemic operations for 7 days. e neuroprotective effect was detected by immunohistochemistry and fluorescence staining, and the neuroprotective mechanism was detected by immunohistochemistry of superoxide dismutase (SOD)-1 and brain-derived neurotrophic factor (BDNF). e results showed that the ischemic injury area pretreated with 200 mg·kg − 1 GLE protected pyramidal neurons (P < 0.05), and the activation of astrocytes (P < 0.05) and microglia (P < 0.05) in ischemic cornu ammonis 1 (CA1) area was significantly inhibited. In addition, GLE pretreatment significantly increased the expression of SOD-1 (P < 0.05) and BDNF (P < 0.05) in CA1 pyramidal cells of pseudo-and ischemic groups. It is suggested that GLE pretreatment can protect neurons from ischemic injury, and its neuroprotective mechanism may be closely related to the increase of SOD-1 and BDNF expression and the decrease of glial cell activation [91]. e effects of G. littoralis extract on the proliferation of hippocampal cells, the differentiation of neuroblasts, and the maturation of new neurons in adult mice were studied by Park et al. 5-Bromine 2-deoxyuridine (BrdU) was stained with double immunofluorescence staining for BrdU and neuron nuclear antigen. In addition, the expression of BDNF and its main receptor tropomyosin-related kinase B (TrkB) was detected by western blotting analysis. e extract of G. littoralis (200 mg·kg − 1 ) significantly increased the protein levels of dentate gyrus (DG) and BrdUt/neuronal nuclear antigen (NeuN) cells in the subgranule area of DG (17.0 ± 1.5 cells/section) and doublecortin cells (72.0 ± 3.8 cells/sections) and significantly increased the protein levels of BDNF and TrkB (23.2% and 24.4% of the vehicle treatment group, respectively) [91].

Antimicrobial Activities.
e root of G. littoralis was extracted using methanol and was separated for the first time by methanol: chloroform silica gel column chromatography Evidence-Based Complementary and Alternative Medicine with different concentration ratios; 1,9-heptadecadiene-4,6diyne-3,8,11-triol and 1,10-heptadecadiene-4,6-diyne-3,8,9triol exhibited antibacterial and antifungal activities [67]. e leaves of G. littoralis were extracted with steam distillation and ether to obtain volatile oil components, which could then be separated to obtain β-pinene and α-pinene. α-Pinene, an essential oil from G. littoralis, exhibits better activity against Trichophyton than that exhibited by β-pinene and the total essential oil from G. littoralis [92]. Nineteen strains of endophytic fungi were obtained from G. littoralis by the plant tissue separation method using Escherichia coli, Staphylococcus aureus, and Candida albicans as indicator strains. Four strains of endophytic fungi had inhibitory effect against Escherichia coli, the ratio of the diameter of bacteriostatic circle of endophytic fungal fermentation concentrate to the diameter of 4 U·mL − 1 gentamicin sulfate bacteriostatic circle (d/D) was 1.07, and 15 strains of endophytic fungi had inhibitory effect on Staphylococcus aureus, and the maximum d/ D value was 0.65. ree strains of endophytic fungi had inhibitory effect on Pseudomonas Albicans. e maximum d/ D value of endophytic fungal fermentation concentrate and 0.2 mg·mL − 1 fluconazole was 1.27 [93].
In addition, Zhao study found that the water-soluble part had a certain antigastric ulcer effect and a certain scavenging effect of free radicals. It was previously reported that watersoluble part of G. littoralis has a good antilipid peroxide effect.
e mechanism of this effect may be due to the promotion the free radical scavenging of gastric mucosa and reduced lipid peroxide [56]. e pharmacological activities of various bioactive ingredients in G. littoralis were presented in Table 3.

Toxicity
G. littoralis is considered a safe Chinese herbal medicine with beneficial effects in traditional use and modern pharmacology research. Modern toxicology research of G. littoralis is relatively rare, and research work is mainly concentrated in China.
Considering relevant historical books and records in China, the codecoction of Glehniae Radix and Radix et Rhizoma Veratri Nigri might produce toxicity or side effects [104]. Zhu et al. conducted a series of acute toxicity tests in vivo using uniform design method (two factors and seven levels) to investigate how the toxicity changed with different concentrations of these two drugs and whether decoction factors were correlated with toxicity. At the maximum Glehniae Radix dosage of 0.04 mL·g − 1 , no mice died. Another study found that the maximum dosage of the decoction of Glehniae Radix was 32 g·kg − 1 , which is 13.3-fold higher than that used in clinical practice, indicating that Glehniae Radix is almost nontoxic when it is used alone. However, in the toxicity study of different ratios of Glehniae Radix and Radix et Rhizoma Veratri Nigri decoction, the aqueous decoction of Radix et Rhizoma Veratri Nigri with the concentration of 2.566 g·kg − 1 (the LD 50 value in the 95% confidence interval is 2.566 g·kg − 1 ), the codecoction, and mixed decoction of Glehniae Radix and Radix et Rhizoma Veratri Nigri with the proportion of 1 : 1 were administrated to the Kunming mice, respectively. e results showed the mortality rate of the mice administrated with mixed decoction of Glehniae Radix and Radix et Rhizoma Veratri Nigri was 25%, while the mortality rate of the codecoction of them was 65%. e toxicity of codecoction was higher than that of mixed decoction in the same dosage of Glehniae Radix and Radix et Rhizoma Veratri Nigri. In addition, when the ratio of Glehniae Radix and Radix et Rhizoma Veratri Nigri decoction increased from 1 : 1 to 1 : 4.19, the toxicity of their codecoction also increased, and the mortality of mice is reached to 90%. It is speculated that the promotion of the dissolution of the toxic component of Radix et Rhizoma Veratri Nigri in co-decoction may be the cause of the higher toxicity seen. erefore, a prescription contained these drugs should be avoided in clinic practice [37].
Further study investigated the compatible effects of Glehniae Radix and Radix et Rhizoma Veratri Nigri decoction on cytochrome P450 isoenzyme activities in rat livers. e Wistar rats in the blank group were administered saline as a control, and the decoction of Radix et Rhizoma Veratri Nigri, the decoction of Glehniae Radix, and their codecoction were daily administrated at the dose of 0.081 g·mL − 1 , 1.08 g·mL − 1 , and 1.161 g·mL − 1 , respectively, for a week. e results showed that compared with the blank control group, the decoction of both Glehniae Radix and Radix et Rhizoma Veratri Nigri can induce CYP2C9 activities in rats, and their codecoction can significantly induce CYP1A2 and CYP2C9 activities. It is speculated that the induction effect of enzyme activity on the compatibility of the two drugs may accelerate the metabolic activation of the toxic components in the Radix et Rhizoma Veratri Nigri and enhance toxicity. Furthermore, compared with the decoction of Glehniae Radix, the CYP3A4 activity was significantly inhibited and the CYP1A2 activity was significantly induced, and there were no effects on the activities of CYP2C9 and CYP2C19 after administration of the codecoction of Glehniae Radix and Radix et Rhizoma Veratri Nigri in rats. It is suggested that when the codecoction of Glehniae Radix and Radix et Rhizoma Veratri Nigri was taken for a long time, the inhibition of CYP3A in rats changes the metabolism and physiological functions of endogenous substances and thus affects the metabolism of some of these components, resulting in toxicity. All these observations provide an experimental basis for the use of G. littoralis with V. nigrum [105].
To date, most of the toxicology research studies have focused on the roots of G. littoralis, and the toxicological investigations are in the basic stage. e aerial parts of this plant are sometimes used as aromatic vegetables, but the toxicity study has not been carried out, and further studies are needed on this herb.

Conservation Status and Proposals for
Glehnia Species e dried root of G. littoralis has been of great value in medicine (traditional medicine use, modern drug research, and development), as food ingredients (soup, porridge), and medicinal material health food (medicinal wine and   24 Evidence-Based Complementary and Alternative Medicine e model of yin deficiency in mice was constructed with thyroxine and reserpine. Highdose group of GLP (800 mg·(kg·d) − 1 ), mediumdose group of GLP (600 mg·(kg·d) − 1 ), and low-dose group of GLP (400 mg·(kg·d) − 1 ) are given by gavage for 6 consecutive days.
GLP obviously increased the weight of yin deficiency mice and also significantly raised the levels of antibody-forming cells in interperitoneal cavity (P < 0.01 or P < 0.05), and enhanced delayed-type hypersensitivity (DTH) reaction in mice (P < 0.01), but it had no effect on peritoneal macrophage coefficient and index. [94] e SFE-CO 2 extraction from Radix G. littoralis Using cyclophosphamide to establish immunosuppressed mice model and the effects of the SFE extraction on it were studied. For 6 consecutive days, the intraperitoneal injection dose was 4 or 2g·kg − 1 ·d − 1 dissolved by DMSO with Glehniae SFE-CO 2 extract.
e SFE extraction restored part of the immunological function in immunosuppressed mice. CD3 + T, CD3 + CD4 + T, and CD3 + CD8 + T in the low-dose group and the high-dose group were all higher than the immunity inhibition group, but lower than the normal control group (P < 0.05). [95] e root of G. littoralis Using cyclophosphamide to establish immunosuppressed mice model. For 10 consecutive days, the intraperitoneal injection dose was 4, 2, or 1 g·kg − 1 with the root of G. littoralis.
G. littoralis can increase the weight of thymus gland and spleen, enhance the ability of mouse peritoneal macrophages to engulf neutral red, and improve the tumor killing rate of mouse lymphocytes and the killing ability of natural killer cells. In vitro immunological activity results showed that the three polysaccharide components exhibited good immune activity. [97] Extracts from leaves and stems of G. littoralis e drug extracts from leaves and stems of G. littoralis were administered to the mice continuously for 15 days, and the intraperitoneal injection dose was 2.34 g·kg − 1 or 0.59 g·kg − 1 . After 15 days, hemolytic value of mice was discussed.
Mice were given different doses of extracts from leaves and stems of G. littoralis. After 15 days compared with the control group, hemolytic value of mice in the water extract 2.34 g·kg − 1 dose group, the alcohol extract 2.34 g·kg − 1 dose group, and the American ginseng capsule group were significantly increased (P < 0.05). Extracts from leaves and stems of G. littoralis can regulate humoral immunity. [68] Evidence-Based Complementary and Alternative Medicine 25  Evidence-Based Complementary and Alternative Medicine 27 drinkable medicinal tea), which has great commercial benefits. G. littoralis is one of the constructive species of the psammophyte community. It is suitable for growing on sandy beach or cultivating in fertile and loose sandy soil. According to peer-reviewed journals and field investigation, G. littoralis is distributed across the sandy seacoast, including China, Korea, Japan, and Russia and it plays an important role in coastal sand fixation and improvement saline-alkali soil [106,107]. However, due to overdevelopment, industrialization, and the urbanization of beaches, as well as the overexploitation of G. littoralis, the wild resources of G. littoralis have been reduced gradually and the species has become increasingly endangered. Moreover, in the process of cultivation, as reported, the seeds of G. littoralis have the characteristics of being in deep dormancy with a high abortion rate. e production of wild G. littoralis has been on the verge of extinction and therefore could not fulfill the increasing market demand [108]. In this case, the cultivated varieties have become the main source of medicinal materials in the market. To ensure the quality of medicine, great attention is needed to protect germplasm resources, improve planting technology, and create suitable growing habitats for the species. Li et al. confirmed that the use of hormones combined with low temperature could significantly advance germination time and germination rate. is method was proven to be able to provide conditions for postmaturation of seed embryos or promote degradation of inhibiting germination substances to break dormancy and increase germination rate. It is beneficial to the artificial cultivation of G. littoralis [109].
Artificial breeding technology of G. littoralis is not only beneficial to the conservation and regeneration of endangered species, but also conducive to alleviation of sharp conflict between the production and demand of medicinal materials. Miao et al. used leaves and stalks as explant on G. littoralis and studied its callus-inducing medium. e experiments show that the best culture media for G. littoralis is 1/2MS + 0.4 mg·L − 1 6-BA + 1.5 mg·L − 1 NAA. is condition can induce callus formation of G. littoralis with high efficiency and provide some theoretical data for the breeding of high-quality seedlings of G. littoralis [110]. Li et al. successfully established the clone of G. littoralis by using the tender stem, which proved the totipotency of the nonmeristematic tissue and cells of G. littoralis.
is technology not only meets the needs of preservation of germplasm of G. littoralis but also ensures many seedlings in cultivation [111]. Song et al. used the method of sequence-related amplified polymorphism to analyze the genetic diversity of 80 individual materials of 8 populations from the genus Glehnia in China, thereby revealing why the germplasm of the herb can be adapted to the local living environment. is technology can be used to G. littoralis germplasm preservation to provide the scientific basis. As discussed before, these methods have broad application prospects in the protection and development of medicinal plant resources [112].
Nowadays, there are many methods to protect the endangered medicinal plants of G. littoralis, such as establishment of natural reserves, off-site protection and germplasm resources, improved breeding, and other ways to prevent the degradation, mixing, quality decline, and curative effect of the varieties of G. littoralis. To sustainably utilize G. littoralis, more focus needs to be on G. littoralis recovery, take acquisition and protection of inherit resources and intellectual property protection as important issues for wild G. littoralis habitat reservation. Transformation from using wild resources to utilizing artificial cultivating resources is a key to drive moderate exploitation of wild G. littoralis habitats and promote the standardization of its production process.

Conclusions and Perspectives
Available literature demonstrates that G. littoralis plays a vital role in TCM and nourishes yin, moistens the lung, expels phlegm, and arrests cough. In the past few decades, different classes of active components that possess multiple pharmacological properties have been reported to exist in G. littoralis. Further, modern clinical studies have evaluated the pharmacological activities of G. littoralis, which are related to its traditional uses. However, shortcomings remain in the utilization of G. littoralis.
Firstly, although it is a common medicine for treatment of lung and stomach diseases, the description of morphology of G. littoralis was not available in early ancient times. e results showed that the ulcer inhibition rate of the watersoluble part groups and the positive control group was 6.4%, 38.5%, and 60.8%, showing a certain antiulcer effect. [56] 28 Evidence-Based Complementary and Alternative Medicine erefore, it is unreasonable for some researchers to assume that the medicinal herbs referred to as Shashen are Adenophora plants, thus warranting further confirmation [20].
Secondly, in clinical application, the root of G. littoralis can be used in combination with a variety of medicinal materials to enhance its efficacy. For example, it combined with Aconiti Lateralis Radix Praeparata, Cinnamomi Ramulus, and Angelicae Sinensis Radix presents significant effect in the treatment of chronic arrhythmia. In addition, its combination with Astragali Radix, Hirudo, and Notoginseng Radix et Rhizoma is used to invigorate qi (the treatment for weakness) and activate blood circulation; it can also be used to treat apoplexy. However, the pharmacological action mechanisms underlying the synergistic effects of G. littoralis with these traditional Chinese medicinal materials are yet to be fully explained, and the other potential therapeutic effects remain unknown.
irdly, although G. littoralis is almost nontoxic, the dose should still be cautiously determined to avoid adverse reactions such as sensitization and irritation. In addition, its combined use with V. nigrum should be avoided. Furthermore, most studies on G. littoralis were mainly focused on its dried roots; thus, future investigations should be performed to evaluate the biological activities of its stems, leaves, and seeds.
Finally, specific studies exist on the cultivation, management, processing, and quality of G. littoralis; however, these are not systematic or comprehensive. Zhang studied the quality of G. littoralis using falcarindiol and panaxynol as the quality standards. e traditional technology of skin removal had significant negative effects on the content of the two active components in G. littoralis [113]. G. littoralis is often confused with A. stricta and other rhizomatous herbs. e identification method recorded in the Chinese Pharmacopoeia only contains characteristics of appearance and microscopic identification; therefore, it is necessary to establish an efficient and scientific method to ensure the safety of this medication [21]. Moreover, herb quality is affected by the geographical region; thus, it is necessary to standardize the management, processing, and quality of G. littoralis to adopt planting practices. Such efforts will lay a solid foundation for the development and utilization of Chinese medicinal resources and the modernization of Chinese medical material and increase the use of Chinese medical practices globally.
To summarize, this review provides an overview of past and current studies on the traditional uses, phytochemistry, pharmacological activities, and toxicity of G. littoralis. However, further studies exploring its efficacy, identifying its active components, and understanding its potential toxicity as a medicinal plant are warranted to ensure its safety for clinical applications. Moreover, it is necessary to conduct an in-depth study on the application of the other parts of this effective Chinese medicinal material.