Study on the dynamic variation of the secondary metabolites in Viscum coloratum using targeted metabolomics

Viscum coloratum (Kom.) Nakai is a well-known medicinal plant. However, the optimal harvest time for V. coloratum is unknown. Few studies were performed to analyze compound variation during storage and to improve post-harvest quality control. Our study aimed to comprehensively evaluate the quality of V. coloratum in different growth stages, and determine the dynamic variation of metabolites. Ultra-performance liquid chromatography tandem mass spectrometry was used to quantify 29 compounds in V. coloratum harvested in six growth periods, and the associated biosynthetic pathways were explored. The accumulation of different types of compounds were analyzed based on their synthesis pathways. Grey relational analysis was used to evaluate the quality of V. coloratum across different months. The compound variation during storage was analyzed by a high-temperature high-humidity accelerated test. The results showed that the quality of V. coloratum was the hightest in March, followed by November, and became the lowest in July. During storage, compounds in downstream steps of the biosynthesis pathway were first degraded to produce the upstream compounds and some low-molecular-weight organic acids, leading to an increase followed by a decrease in the content of some compounds, and resulted in a large gap during the degradation time course among different compounds. Due to the rapid rate and large degree of degradation, five compounds were tentatively designated as "early warning components" for quality control. This report provides reference for better understanding the biosynthesis and degradation of metabolites in V. coloratum and lays a theoretical foundation for rational application of V. coloratum and better quality control of V. coloratum during storage.

Exploring the resources of the genus Viscum for potential therapeutic applications

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Viscum comprises approximately 100 species that are mainly distributed across Africa, Asia and Europe. The extracts and preparations of Viscum species are widely used as common complementary and alternative medicines in the treatment of rheumatism and cancer.

AIM OF THE REVIEW

This review aims to explore the medicinal properties of twelve species belonging to the genus Viscum for potential therapeutic applications.

MATERIALS AND METHODS

We collected online information (including PubMed, CNKI, Google Scholar, and Web of Science) from January 1915 to April 2021 and knowledge from classical books on Chinese herbal medicines available for 12 species of the genus Viscum, including Viscum coloratum (Kom.) Nakai, Viscum album L., Viscum articulatum Burm. f., Viscum liquidambaricola Hayata, Viscum ovalifolium DC., Viscum capitellatum Sm., Viscum cruciatum Sieber ex Boiss., Viscum nudum Danser, Viscum angulatum B.Heyne ex DC., Viscum tuberculatum A.Rich., Viscum multinerve Hayata, and Viscum diospyrosicola Hayata.

RESULTS

At least 250 different compounds have been reported across twelve Viscum species, including amino acid and peptides, alkaloids, phenolic acids, flavonoids, terpenoids, carbohydrates, fatty acids, lipids, and other types of compounds. In particular, for Viscum coloratum (Kom.) Nakai and Viscum album L., the plants, preparations, and bioactive components have been thoroughly reviewed. This has allowed to elucidate the role of active components, including lectins, viscotoxins, flavonoids, terpenoids, phenolic acids, and polysaccharides, in multiple bioactivities, such as anti-cancer, anti-rheumatism arthralgia, anti-inflammation, anti-cardiovascular diseases, enhancing immunity, and anti-chemotherapy side effects. We also evaluated quality control methods based on active compounds, in vivo exposure compounds, and discriminated chemical markers.

CONCLUSIONS

This is the first report to systematically review the pharmaceutical development history, chemical composition, clinical evidence, pharmacological activity, discriminated chemical markers, in vivo exposure, and quality control on twelve distinct species of Viscum plants with medicinal properties. The significant safety and efficacy, along with the minor side effects are constantly confirmed in clinics. The genus Viscum is thus an important medicinal resource that is worth exploring and developing in future pharmacological and chemical studies.

Chemical constituents of Viscum coloratum (Kom.) Nakai and their cytotoxic activities

A new diarylheptanoid, (1 R,2S,3S,5S)-2,3-dihydroxy-3',3''-dimethoxy-4'-de-O-methylcentrolobine (1) and a new bisabolane-type sesquiterpenoid, (1 R,7S)-1,12,13-trihydroxybisabola-3,10-diene (2), together with nineteen known compounds (3-21) were isolated from the EtOH extract of the stems and branches of Viscum coloratum (Kom.) Nakai. Their structures were elucidated by extensive analysis of 1 D and 2 D NMR spectra and from the HRESIMS. All the compounds were evaluated for their cytotoxic activity against eight human tumor cell lines.

Establishment of conventional PCR and real-time PCR assays for accurate, rapid and quantitative authentication of four mistletoe species

Adulterants in processed food and herbal medicines reduce their safety, quality control, or pharmacological efficacy. Four mistletoe species, including Viscum coloratum, inhabit Korea. Leaves and branches of V. coloratum, defined as edible or medicinal mistletoe species in Korean, are used to prepare Korean herbal medicines as well as leached tea. However, other mistletoe species including Taxillus sutchuenensis var. duclouxii, Korthalsella japonica, and Loranthus tanakae are frequently distributed as authentic V. coloratum in Korean markets because of similarities in the branches morphology and Korean names of these species with V. coloratum. Although herbal medicines and food products prepared from the other mistletoe species are inauthentic, they are sold at high prices because of the rarity of these species. Thus, it is important to distinguish between authentic and inauthentic adulterant mistletoe species. In this study, we developed species-specific primer, based on matK sequences, suitable for both conventional PCR and real time PCR (qPCR) assay. These assays allowed rapid discrimination among all four mistletoe species. Moreover, qPCR assay enabled the detection of trace amounts of adulterant mistletoe species in V. coloratum samples. Furthermore, we used these assays to monitor commercial mistletoe products distributed in Korean markets. Our data suggest that these methods would serve as a reliable genetic tool to prevent adulteration and standardize the quality of commercial V. coloratum products.

The complete chloroplast genome sequence of Viscum coloratum (Viscaceae), a semiparasitic medicinal plant

Viscum coloratum (Viscaceae) is a kind of semiparasitic shrub used as medicinal plant. The complete chloroplast (cp) genome of V. coloratum was sequenced and characterized in this study. Length of total cp genome is 128,744 bp, which is constructed by four typical regions including a large single-copy region (LSC, 73,684 bp), a small single-copy region (SSC, 8630 bp) and a pair of inverted-repeat regions (IRs, 23,215 bp). 100 unique genes are predicted including 68 protein-coding genes, 28 tRNA genes and four rRNA genes. Phylogenetic analysis were performed based on 30 shared genes of 12 species in Santalales using maximum likelihood method. The results showed a close relationship between V. coloratum and V. album. The complete cp genome of V. coloratum would provide valuable genetic resources for further study on phylogeny, population genetics and identification in Viscum.

Development of microsatellite markers for Viscum coloratum (Santalaceae) and their application to wild populations

PREMISE OF THE STUDY

Microsatellite primers were developed for Viscum coloratum (Santalaceae), a semiparasitic medicinal plant that is known for its anticancer properties. Due to excessive human harvesting and loss of suitable habitat of its populations, it has become a potentially threatened species requiring immediate conservation efforts.

METHODS AND RESULTS

Based on transcriptome data for V. coloratum, 124 primer pairs were randomly selected for initial validation, of which 19 yielded polymorphic microsatellite loci, with two to six alleles per locus. The usefulness of these markers was assessed for 60 individuals representing three populations of V. coloratum. Observed and expected heterozygosity values ranged from 0.033 to 0.833 and 0.032 to 0.672, respectively. Cross-species amplification for 19 loci in the related species V. album was conducted.

CONCLUSIONS

The 19 newly developed loci are expected to be useful for studying the population genetics and ecological conservation of V. coloratum.

A study of pharmacokinetic interactions among co-existing ingredients in Viscum coloratum after intravenous administration of three different preparations to rats

Background:

Viscum coloratum (Komar) Nakai, known as Hujisheng in china, has been widely used as a herb medicine to treat a variety of diseases, including cardiovascular diseases, cancer, hypertension, hepatitis and hemorrhage.

Objective:

The aim was to investigate pharmacokinetic interactions among co-existing ingredients in V. coloratum after intravenous administration of three different preparations (four monomer solutions, the mixture of them and Viscum coloratum extracts) to rats.

Materials and Methods:

After protein precipitation pretreatment with plasma samples, high performance liquid chromatographic methods were developed and applied to quantitatively determinate the four components [syringin (Syri), homoeriodictyol-7-O-β-D-glycoside (Hedt-III), homoeriodictyol-7-O-β-D-apiose (1 → 2)-β-D-glycoside (Hedt-II) and homoeriodictyol-7-O-β-D-apiosiyl-(1 → 5)-β-D-apiosyl-(1 → 2)-β-D-glycoside (Hedt-I)]. The pharmacokinetic parameters (Area under the curve [AUC_(0-t)], AUC_(0-∞), t_1/2) were calculated using DAS 2.1 software (Chinese Pharmacological Society, Shanghai, China) and compared statistically by One-way analysis of variance using SPSS software (18.0, Chicago, IL, USA) with P < 0.05 considered statistically significant.

Results:

Good linearities were achieved in the measured concentration range with R² it0.9920. Precision, accuracy and extraction recovery were all within the acceptable range. For Syri, there was a significant difference only on t_1/2 among three treatment groups. For Hedt-I, Hedt II and Hedt-III, three flavonoid glycosides, the change of AUC_(0-t), AUC_(0-∞) and t_1/2 were markedly distinctive and even converse.

Conclusion:

Complex, extensive pharmacokinetic interactions were observed among these components in V. coloratum. They were mutually influenced by the in vivo absorption, distribution, metabolism and elimination. The result suggested traditional Chinese medicine was a complicated system, and we should take a scientific and dialectic view in the research and development processes.

Development of the fingerprints for the quality evaluation of Viscum coloratum by high Performance liquid chromatography

A high-Performance liquid chromatography coupled ultraviolet (HPLC-UV) method was developed for a chemical fingerprint analysis of Viscum coloratum. Eighteen peaks were selected as the common peaks and Homoeriodictyol-7-0-β-D-apiosiyl-(1→2)-β-D-glucoside was used as a reference. The relative areas of common peaks were used for hierarchical clustering analysis and similarity calculation. Thirty-seven samples collected from different sources were classified into five groups. The similarities of 21 batches Viscum coloratum samples were beyond 0.90. The results obtained suggest that the Chromatographie fingerprint can efficiently identify Viscum coloratum. Additionally, the fingerprints can then be used to evaluate the correlation between Viscum coloratum and hosts.