Novel functions of herbal medicines in dendritic cells: role of Amomi Semen in tumor immunity

Chemistry and bioactivity of plants from the genus Amomum

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Amomum belonging to the family Zingiberaceae, is mainly distributed in tropical regions of Asia and Oceania. Their fruits and seeds are valuable traditional medicine and used extensively, particularly in South China, India, Malaysia, and Vietnam. The genus Amomum has long been used for treating gastric diseases, digestive disorder, cancer, hepatopathy, malaria, etc. AIMS OF THE REVIEW: The main purpose of this review is to provide the available information on the traditional medicinal uses, phytochemistry, and pharmacology aspects of the genus Amomum in order to explore the trends and perspectives for further studies on its non-volatile constituents.

MATERIALS AND METHODS

The present review collected the literatures published prior to 2020 on the traditional medicinal uses, phytochemistry, and pharmacology of the genus Amomum. The available literatures were extracted from scientific databases, such as Sci-finder, PubMed, Web of Science, Google Scholar, Baidu Scholar, and CNKI, books, and others.

RESULTS

Herein, we summarize all 166 naturally occurring non-volatile compounds from 16 plants of the genus Amomum reported in 171 references, including flavonoids, terpenoids, diarylheptanoids, coumarins, etc. Triterpenes and flavonoids are the main constituents among these compounds and maybe play an important role in the activities directly or indirectly. As traditional medicine, the plants from the genus Amomum have been usually used in some traditional herbal prescriptions, and pharmacological researches in vitro and in vivo revealed that the extracts possessed significant antioxidant, anti-inflammatory, anti-allergic activities, etc. CONCLUSION: The review systematically summarizes current studies on traditional medicinal uses, phytochemistry, pharmacological activity on the plants from the genus Amomum. To date, the majority of publications still focused on the research of volatile constituents. However, the promising preliminary data of non-volatile constituents indicated the research potential of this genus in phytochemical and pharmacological aspects. Furthermore, the further in-depth investigations on the safety, efficacy, as well as the stereo-chemistry and structure-activity relationships of pure compounds from this genus are essential in the future.

Spiky titanium dioxide nanoparticles-loaded Plantaginis Semen polysaccharide as an adjuvant to enhance immune responses

The purpose of this study was to prepare spiky titanium dioxide nanoparticles-loaded Plantaginis Semen polysaccharide (SN-TiO₂-PSP), and the structural characterization and immune response of infectious laryngotracheitis (ILT) vaccine in Hetian chickens were investigated. The structural characterization of SN-TiO₂-PSP was analyzed by FT-IR, TEM, and TGA analysis. And the immune organs indexes, lymphocytes proliferation, specific antibody levels, and ratios of CD4⁺ and CD8⁺ T lymphocytes were studied. Structural characterization results showed that SN-TiO₂-PSP has a typical polysaccharide absorption peak and good stability. The SN-TiO₂-PSP's shape was similar to sea urchin, and its zeta potential and particle size were 27.56 mV and 976.11 nm, respectively. In vivo results showed that SN-TiO₂-PSP could enhance the proliferation of peripheral lymphocytes, specific antibody levels, CD4⁺ and CD8⁺ T lymphocytes ratios, IL-4 and INF-γ levels in Hetian chickens vaccinated with ILT vaccine on D₇, D₁₄, D₂₁, and D₂₈. In addition, SN-TiO₂-PSP not only enhanced the indexes of immune organs but also promoted the development of immune organs. Therefore, SN-TiO₂-PSP has immune adjuvant activity and may become a new potential immune adjuvant.

A review of the ethnopharmacology, phytochemistry and pharmacology of Notopterygium incisum

ETHNOPHARMACOLOGICAL RELEVANCE

Notopterygium incisum Ting ex H.T. Chang, known in Chinese as 'Qianghuo' is a traditional Chinese medicinal herb with the rhizome and roots associated with meridians of the kidney and urinary bladder. It is pungent, bitter and warm in nature. It has been used over the years to disperse cold, prevent painful obstructions from wind, damp and warm pain. It has also been used with other herbs to treat wind-cold exterior syndrome and wind-cold-damp bi-syndromes and has been known to grow well in regions of high altitude such as Gansu, Tibet etc.

THE AIM OF THE REVIEW

This systematic review focuses on the ethnopharmacological uses of this herb, including recent advances on the phytochemical and pharmacological study of N. incisum. Recent analytical methods developed for the quantitative and qualitative determination of constituents in this herb have also been reviewed. Additionally, future trends and prospects in the study of this herb have been proposed.

MATERIALS AND METHOD

Various literature and electronic databases such as Pubmed, Science Direct, Springer, Wiley etc were searched and data obtained. Other online academic libraries such as Google Scholar and ethnopharmacological literature were searched systematically for more information on the herb.

RESULTS

This review focuses on the ethnopharmacological uses of N. incisum and also the various chemical constituents present in the herb and their various therapeutic effects such as analgesic, anti-inflammatory, anti-cancer and antioxidants effects. Analytical methods developed for the quantitative and qualitative determination of various compounds in this herb were further reviewed.

CONCLUSION

In this paper, we have reviewed various researches conducted on N. incisum especially in areas of its ethnopharmacological use, phytochemicals, pharmacology and developed analytical methods. This herb has been used over the years in treating headache, rheumatoid arthritis, cold, diaphoretic etc, prompting many types of research into identifying which compounds are responsible for these activities and their mechanism of action. More research is needed in the area of pharmacokinetics and toxicology to give further information on the clinical use and control the quality of the herb.

Modulation of dendritic cell immune functions by plant components

Dendritic cells (DCs) are the key linkage between innate and adoptive immune response. DCs are classified as specialized antigen-presenting cells that initiate T-cell immune responses during infection and hypersensitivity, and maintain immune tolerance to self-antigens. Initiating T-cell immune responses may be beneficial in infectious diseases or cancer management, while, immunosuppressant or tolerogenic responses could be useful in controlling autoimmunity, allergy or inflammatory diseases. Several types of plant-derived components show promising properties in influencing DC functions. Various types of these components have been proven useful in clinical application and immune-based therapy. Therefore, focusing on the benefits of plant-based medicine regulating DC functions may be useful, low-cost, and accessible strategies for human health. This review illustrates recent studies, investigating the role of plant components in manipulating DC phenotype and function towards immunostimulating or immunosuppressing effects either in vitro or in vivo.

The immunoregulatory effects of Chinese herbal medicine on the maturation and function of dendritic cells

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese herbal medicine (CHM) has a long-history for treatment of various human diseases including tumors, infection, autoimmune diseases in Asian countries, especially in China, Japan, Korea and India. CHM was traditionally used as water extracts and many Chinese herbs were considered to be good for health, which can regulate immune system to protect host from diseases. With the progress of technology, the components of CHM were identified and purified, which included polysaccharides, saponins, phenolic compounds, flavonoids and so on. Recently, accumulating evidence indicates that CHM and its components can regulate immune system through targeting dendritic cells (DCs). We hereby reviewed the immunoregulatory effects of CHM on the maturation, cytokine production and function of DCs. This should help to shed light on the potential mechanism of CHM to improve the usage and clinical efficacy of CHM.

MATERIALS AND METHODS

Literatures about the effects of CHM on DCs were searched in electronic databases such as Pubmed, Google Scholar and Scopus from 2000 to 2014. 'CHM', 'DC' or 'immune' were used as keywords for the searches. We only reviewed literatures published in English.

RESULTS

Over 600 publications were found about 'CHM&immune' and around 120 literatures about 'CHM&DC' were selected and reviewed in this paper. All publications are backed by preclinical or clinical evidences both in vitro and in vivo. Some CHM and its components promote the maturation, pro-inflammatory cytokine production and function of DCs and as the adjuvant enhance immune responses against tumor and infection. In contrast, other CHM and its components suppress the activation status of DCs to induce regulatory T cells, inhibit allergic and inflammatory responses, ameliorate autoimmune diseases, and prolong the allograft survival. A large body of evidence shows that CHM and its components regulate the activation status of DCs through TLRs, NF-κB, MAPK signaling pathways.

CONCLUSION

This review provides useful information for understanding the mechanism of CHM on the treatment of diseases, which facilitates to improve the efficacy of CHM. Based on the immunoregulatory effects of CHM on DCs, it indicated that some CHM and its components could be use to develop adjuvant to enhance antigen-specific immune responses or tolerogenic adjuvant to generate antigen-specific immune tolerance.

A novel polysaccharide from the seeds of Plantago asiatica L. induces dendritic cells maturation through toll-like receptor 4

In this study, we investigated the effect of a polysaccharide purified from the seeds of Plantago asiatica L. (PLP-2) on the phenotypic and functional maturation of murine bone marrow-derived dendritic cells (DCs) and relevant mechanisms. The results showed that PLP-2 increased the expression of maturation markers major histocompatibility complex II, CD86, CD80, and CD40 on DCs. Consistent with the changes in the phenotypic markers, functional assay for DCs maturation showed that PLP-2 decreased DCs endocytosis and increased intracellular interleukin (IL)-12 levels and allostimulatory activity. Furthermore, using a syngeneic T cell activation model, we found that PLP-2 treated DCs presented ovalbumin antigen to T cells more efficiently as demonstrated by increased T cell proliferation. In addition, the effects of PLP-2 on DCs were significantly impaired by treating the cells with anti-TLR4 antibody prior to PLP-2 treatment, implying direct interaction between PLP-2 and TLR4 on cell surface. These results suggested that PLP-2 may induce DCs maturation through TLR4. Our results may have important implications for our understanding on the molecular mechanisms of immunopotentiating action of the polysaccharides from plants.

Extraction of polysaccharides and the antioxidant activity from the seeds of Plantago asiatica L

The extraction conditions of polysaccharides from Plantago asiatica L. seeds were investigated. Four parameters affecting the polysaccharides extraction, extraction times, water to sample, extraction temperature and single extraction time, were determined by orthogonal experiments. Under the optimized conditions, the polysaccharides yield of P. asiatica L. seeds was 2.467%. The antioxidant activities of the polysaccharides were investigated. The reducing power of the polysaccharides was dose dependent, and the reducing capacity of the polysaccharides was inferior to butylated hydroxytoluene, which is known to be a strong reducing agent. The scavenging rates of the polysaccharides on superoxide and 1,1-diphenyl-2-picrylhydrazyl radicals were 79.7% and 81.4%, at polysaccharides concentration of 0.75 mg/mL, respectively, a scavenging rates approximately similar to that of 0.75 mg/mL ascorbic acid (83.5% and 85.1%, respectively). Furthermore, it exhibited a moderate concentration-dependent ABTS radical scavenging activity, ferrous ion chelating potency and H(2)O(2) scavenging activity. The data obtained in the in vitro models clearly establish the antioxidant potency of the polysaccharides extracted from Semen Plantaginis.

The herbal medicine compound falcarindiol from Notopterygii Rhizoma suppresses dendritic cell maturation

Dendritic cells (DCs) are important for regulating the immune response. We report an herbal medicine compound called falcarindiol that affects DC function. Ethanol extracts of 99 crude drugs that are the main components of 210 traditional Japanese medicines (Kampo medicine) approved by the Ministry of Health, Labor and Welfare in Japan were prepared and screened using the murine epidermal-derived Langerhans cell line XS106. Notopterygii Rhizoma strongly suppressed major histocompatibility complex (MHC) class II expression in XS106 cells. Activity-guided fractionation led to the isolation and identification of falcarindiol as a principal active compound in Notopterygii Rhizoma. Falcarindiol (1-5 microM) dose-dependently suppressed MHC II expression in XS106 cells. Fresh-isolated bone marrow-derived DCs were examined for the production of MHC II, CD80, CD86, interleukin (IL)-12p70, and IL-10. Treatment of bone marrow-derived DCs with 5 muM falcarindiol significantly inhibited lipopolysaccharide-induced phenotype activation and cytokine secretion and inhibited MHC II expression by CD40 ligation, but not phorbol 12-myristate 13-acetate + ionomycin or IL-12. Falcarindiol inhibited DC maturation by blocking the canonical pathway of nuclear factor-kappaB and phosphorylated p38. Topical application of 0.002 and 0.01% falcarindiol before sensitization dose-dependently suppressed delayed-type hypersensitivity to ovalbumin (p < 0.01). Falcarindiol induces immunosuppressive effects in vitro and in vivo and might be a novel therapy for autoimmune or allergic diseases.