Quality variation and salt-alkali-tolerance mechanism of Cynomorium songaricum: Interacting from microbiome-transcriptome-metabolome

Addressing soil salinization and implementing sustainable practices for cultivating cash crops on saline-alkali land is a prominent global challenge. Cynomorium songaricum is an important salt-alkali tolerant medicinal plant capable of adapting to saline-alkali environments. In this study, two typical ecotypes of C. songaricum from the desert-steppe (DS) and saline-alkali land (SAL) habitats were selected. Through the integration of multi-omics with machine learning, the rhizosphere microbial communities, genetic maps, and metabolic profiles of two ecotypes were created and the crucial factors for the adaptation of C. songaricum to saline-alkali stress were identified, including 7 keystone OTUs (i.e. Novosphingobium sp., Sinorhizobium meliloti, and Glycomyces sp.), 5 core genes (cell wall-related genes), and 10 most important metabolites (i.e. cucurbitacin D and 3-Hydroxybutyrate) were identified. Our results indicated that under saline-alkali environments, the microbial competition might become more intense, and the microbial community network had the simple but stable structure, accompanied by the changes in the gene expression related to cell wall for adaptation. However, this regulation led to the reduction in active ingredients, such as the accumulation of flavonoids and organic acid, and enhanced the synthesis of bitter substances (cucurbitacin D), resulting in the decrease in the quality of C. songaricum. Therefore, compared to the SAL ecotype, the DS was more suitable for the subsequent development of medicinal and edible products of C. songaricum. Furthermore, to explore the reasons for this quality variation, we constructed a comprehensive microbial-genetic-metabolic regulatory network, revealing that the metabolism of C. songaricum was primarily influenced by genetic factors. These findings not only offer new insights for future research into plant salt-alkali tolerance strategies but also provide a crucial understanding for cultivating high-quality medicinal plants.

[Content analysis and quality evaluation of main active components and mineral elements of Cynomorium songaricum in different habitats]

To clarify the content characteristics of the main active components and mineral elements of Cynomorium songaricum under different habitat conditions, and further explore the relationship between the quality of C. songaricum and habitats, this study took C. songaricum from 25 different habitats in China as the research object, and measured the contents of 8 main active components and 12 mineral elements separately. Diversity analysis, correlation analysis, principal component analysis and cluster analysis were carried out. The results showed that the genetic diversity of total flavonoids, ursolic acid, ether extract, potassium(K), phosphorus(P) and zinc(Zn) in C. songaricum was high. The coefficient of variation of crude polysaccharide, ether extract, gallic acid, protocatechuic aldehyde, catechin, epicatechin, calcium(Ca), sodium(Na), magnesium(Mg), sulfur(S), iron(Fe), manganese(Mn), selenium(Se) and nickel(Ni) were all over 36%, indicating that the quality of C. songaricum was significantly affected by habitats. There were strong synergistic and weak antagonistic effects among the contents of the 8 active components, and complex antagonistic and synergistic effects among the contents of the 12 mineral elements. Principal component analysis revealed that crude polysaccharide, ursolic acid, catechin, epicatechin and total flavonoids could be used as the characteristic components to evaluate the quality of C. songaricum, and Na, copper(Cu), Mn and Ni were the characteristic elements to evaluate the quality of C. songaricum. In cluster ana-lysis, the second group with the main active components as cluster center had better quality in terms of the content of active substances, and the second group with the mineral elements as cluster center had higher utilization potential in the exploitation of mineral elements. This study could provide a basis for resource evaluation and breeding of excellent varieties of C. songaricum in different habitats, and provide a reference for cultivation and identification of C. songaricum.

Identification and bioactivity evaluation of flavan-3-ols in the milk of dairy sheep fed Cynomorium songaricum

Cynomorium songaricum is a traditional medicine and also a food material that is eaten raw or processed as tea or beverages. As a featured plant in semi-desert grasslands, C. songaricum is also eaten by the cattle and sheep in the area. This research study fed dairy sheep C. songaricum to determine the flavan-3-ols in sheep milk. Catechin (Cat), epicatechin (Epi), procyanidin A1 (A1), procyanidin A2 (A2), and procyanidin B1 (B1) were detected in sheep milk with the concentration being Epi > A2 > Cat > B1 > A1 at 24 h after the administration of C. songaricum. Neither A1 nor A2 were detected in the methanol extract of C. songaricum. Cysteine degradation of the plant revealed that in addition to Epi, A2 was the extending unit of the polymeric flavan-3-ols in C. songaricum, indicating that A2 is released digestively from the polymers and enters the milk. Procyanidin B-1 was converted to A1 on incubation in raw but not heated milk, indicating that the A1 in milk is the enzymatically transformed product of B1. Accelerated oxidation showed that the flavan-3-ols, B1, Cat, and Epi significantly protects the unsaturated triacyglycerols in the milk from oxidation. The flavan-3-ol could slow down the oxidation of glutathione and the latter may play an important role in preventing the milk triglycerides from oxidation. Flavan-3-ols are polyphenols with many health benefits. The present research revealed the antioxidant activities of flavan-3-ols that could be absorbed to sheep milk, adding new evidences for the values of these flavan-3-ols and for the milk.

Transcriptomics Reveals Host-Dependent Differences of Polysaccharides Biosynthesis in Cynomorium songaricum

Cynomorium songaricum is a root holoparasitic herb that is mainly hosted in the roots of Nitraria roborowskii and Nitraria sibirica distributed in the arid desert and saline-alkaline regions. The stem of C. songaricum is widely used as a traditional Chinese medicine and applied in anti-viral, anti-obesity and anti-diabetes, which largely rely on the bioactive components including: polysaccharides, flavonoids and triterpenes. Although the differences in growth characteristics of C. songaricum between N. roborowskii and N. sibirica have been reported, the difference of the two hosts on growth and polysaccharides biosynthesis in C. songaricum as well as regulation mechanism are not limited. Here, the physiological characteristics and transcriptome of C. songaricum host in N. roborowskii (CR) and N. sibirica (CS) were conducted. The results showed that the fresh weight, soluble sugar content and antioxidant capacity on a per stem basis exhibited a 3.3-, 3.0- and 2.1-fold increase in CR compared to CS. A total of 16,921 differentially expressed genes (DEGs) were observed in CR versus CS, with 2573 characterized genes, 1725 up-regulated and 848 down-regulated. Based on biological functions, 50 DEGs were associated with polysaccharides and starch metabolism as well as their transport. The expression levels of the selected 37 genes were validated by qRT-PCR and almost consistent with their Reads Per kb per Million values. These findings would provide useful references for improving the yield and quality of C. songaricum.

Anticancer Activity of Cynomorium coccineum

The extensive applications of Cynomorium species and their rich bioactive secondary metabolites have inspired many pharmacological investigations. Previous research has been conducted to examine the biological activities and numerous interesting pharmaceutical activities have been reported. However, the antitumor activities of these species are unclear. To understand the potential anticancer activity, we screened Cynomorium coccineum and Cynomorium songaricum using three different extracts of each species. In this study, the selected extracts were evaluated for their ability to decrease survival rates of five different cancer cell lines. We compared the cytotoxicity of the three different extracts to the anticancer drug vinblastine and one of the most well-known medicinal mushrooms Amaurederma rude. We found that the water and alcohol extracts of C. coccineum at the very low concentrations possessed very high capacity in decreasing the cancer cells viability with a potential inhibition of tumorigenesis. Based on these primitive data, we subsequently tested the ethanol and the water extracts of C. coccineum, respectively in in vitro and in vivo assays. Cell cycle progression and induction of programmed cell death were investigated at both biological and molecular levels to understand the mechanism of the antitumor inhibitory action of the C. coccineum. The in vitro experiments showed that the treated cancer cells formed fewer and smaller colonies than the untreated cells. Cell cycle progression was inhibited, and the ethanol extract of C.coccineum at a low concentration induced accumulation of cells in the G1 phase. We also found that the C. coccineum’s extracts suppressed viability of two murine cancer cell lines. In the in vivo experiments, we injected mice with murine cancer cell line B16, followed by peritoneal injection of the water extract. The treatment prolonged mouse survival significantly. The tumors grew at a slower rate than the control. Down-regulation of c-myc expression appeared to be associated with these effects. Further investigation showed that treatment with C.coccineum induced the overexpression of the tumor suppressor Foxo3 and other molecules involved in inducing autophagy. These results showed that the C. coccineum extract exerts its antiproliferative activity through the induction of cell death pathway. Thus, the Cynomorium plants appear to be a promising source of new antineoplastic compounds.

polysaccharides

The plant, Cynomorium songaricum Rupr., is used as a traditional medicine in China and Mongolia. In the present study, two new water-soluble polysaccharides isolated from C. songaricum Rupr. were purified by successive Sephadex G-75 and G-50 column chromatographies and then characterized by high resolution NMR and IR spectroscopies. The molecular weights of two polysaccharides were determined by an aqueous GPC to be [Formula: see text] = 3.7 × 10(4) and 1.0 × 10(4), respectively. In addition, it was found that the polysaccharide with the larger molecular weight was an acidic polysaccharide. It was found that the iodine-starch reaction of both isolated polysaccharides was negative and the methylation analysis gave 2, 4, 6-tri-O-methyl alditol acetate as a main product. NMR and IR measurements and sugar analysis revealed that both polysaccharides had a (1 → 3)-α-d-glucopyranosidic main chain with a small number of branches. After sulfation, the sulfated C. songaricum Rupr. polysaccharides were found to have a potent inhibitory effect on HIV infection of MT-4 cells at a 50% effective concentration of 0.3-0.4 μg/ml, a concentration that has almost the same high activity as standard dextran and curdlan sulfates, EC50 = 0.35 and 0.14 μg/ml, respectively. The 50% cytotoxic concentration was low, CC50>1000 μg/ml. In addition, the interaction between the sulfated polysaccharides and poly-l-lysine as a model protein compound was investigated by a surface plasmon resonance to reveal the anti-HIV mechanism.

The Effects of Cynomorium songaricum on the Reproductive Activity in Male Golden Hamsters

Cynomorium songaricum (CS) has been used in traditional Korean medicine in treating male impotence and sexual dysfunction. We investigated the effects of aqueous CS extract on the reproductive activity of golden hamsters whose spermatogenetic capacity is active in summer and inactive in winter. The animals were divided into 5 groups: long photoperiod (LP) control, short photoperiod (SP) control, and SP animals treated with low, middle, or high concentrations of CS. The animals were orally ingested with low (0.5 g/kg), middle (1.0 g/kg), or high (2.5 g/kg) concentrations of the aqueous extracts for 8 weeks on the daily basis. The control animals received the vehicle. As results, the LP control animals showed active testicular function but SP control animals displayed remarkably reduced testicular weights. The outcomes of the reproductive activity from low and middle concentrations of CS treatments were identical and marked as low dose. The consequences were a partial blocking of regressing activity by SP. On the other hand, the animals treated with high dose of CS extract showed remarkable significance in comparison to the SP control, indicative of a complete blocking effect of the CS on the regressing testes by SP. There were a dose-dependent effects of the CS on the sexual function. These results suggest that the CS extract promotes the male fertility by strengthening the spermatogenesis in the golden hamsters.