In vivo and in vitro anti-inflammatory effects of ethanol fraction from Periploca forrestii Schltr

Investigation of the Mechanism of Action of Periploca forrestii Schltr. Extract on Adjuvant Collagen Rats Based on UPLC-Q-Orbitrap-HRMS Non-Targeted Lipidomics

Periploca forrestii Schltr. (P. forrestii) is a classical medicinal plant and is commonly used in traditional medicine for the treatment of rheumatoid arthritis, soft tissue injuries, and traumatic injuries. The aim of this study was to evaluate the anti-arthritic effects of three fractions of P. forrestii alcoholic extracts (PAE), P. forrestii water extracts (PWE), and total flavonoids from P. forrestii (PTF) on Freund's complete adjuvant (FCA)-induced arthritis in rats, and to use a non-targeted lipidomic method to investigate the mechanism of action of the three fractions of P. forrestii in the treatment of rheumatoid arthritis. To assess the effectiveness of anti-rheumatoid arthritis, various indicators were measured, including joint swelling, histopathological changes in the joints, serum cytokines (tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6)), and the joint inflammatory substance prostaglandin E2 (PGE2). Finally, ultra-performance liquid chromatography-quadrupole-orbitrap-high-resolution mass spectrometry (UPLC-Q-Orbitrap-HRMS) was used to determine the non-targeted lipid histology of the collected rat serum and urine samples to investigate the possible mechanism of action. PWE, PAE, and PTF were all effective in treating FCA-induced rheumatoid arthritis. The administered groups all reduced joint swelling and lowered serum inflammatory factor levels in rats. In the screening of lipid metabolite differences between serum and urine of the rat model group and the normal group, a total of 52 different metabolites were screened, and the levels of lipid metabolites in PWE, PAE, and PTF were significantly higher than those in the normal group after administration. In addition, PWE, PAE, and PTF may have significant therapeutic effects on FCA-induced arthritis by modulating nicotinic acid, nicotinamide, and histidine metabolic pathways.

A review on traditional usages, chemical constituents and pharmacological activities of periploca forrestii schltr

ETHNOPHARMACOLOGICAL RELEVANCE

Periploca forrestii Schltr. was listed as a classical medicinal plant in "Miao medicine", which is a branch of traditional Chinese medicine (TCM). According to the theory of TCM, P. forrestii has the efficacy of relaxing tendons and activating collaterals, and dispelling wind and eliminating dampness. Hence, it was often used for the therapy of rheumatoid arthritis and traumatic injury in clinical practice.

AIMS OF THE REVIEW

This review aims to present comprehensive information for the research progress of P. forrestii. The researches on botany, traditional uses, phytochemistry, pharmacology and toxicology of the plant are summarized. We mainly focus on the phytochemical and pharmacological investigations. As a representative class of phytochemicals in P. forrestii, more attention is paid to cardiac glycosides. The insights into potential action of mechanisms and possible future studies on P. forrestii are also discussed.

MATERIALS AND METHODS

Relevant literature was acquired from scientific databases including Google Scholar, Web of Science, Scifinder, Baidu Scholar, PubMed and Chinese national knowledge infrastructure. Monographs and Chinese pharmacopoeia were also utilized as references.

RESULTS

To date, all kinds of phytochemical constituents have been isolated and identified from this plant including cardiac glycosides, steroids, terpenoids, flavonoids, phenylpropanoids, quinones, organic phenolic acids and others. Among these, cardiac glycosides were considered as the major ingredients and bioactive materials. Modern pharmacological studies demonstrated that the plant possessed extensive bioactivity, such as anti-inflammatory and analgesic effects, immunosuppressive action, wound healing activity, antioxidant, anti-tumor and, cardiotonic properties.

CONCLUSIONS

As an important medicinal plant, lots of studies have proved that P. forrestii has significant therapeutical effects, especially on rheumatoid arthritis and traumatic injury. These results provide modern scientific evidence for traditional use and contribute to the development of novel remedies for chronic diseases. However, the exact mechanism of action remains to be elucidated. Furthermore, the long-term in vivo toxicity and clinical efficacy also require in-depth exploration in the future.

Saponin from Periploca forrestii Schltr Mitigates Oxazolone-Induced Atopic Dermatitis via Modulating Macrophage Activation

Atopic dermatitis (AD) is a relapsing, acute, and chronic skin disease featured by intractable itching, eczematous skin. Conventional therapies based on immunosuppression such as corticosteroids are associated with multiple adverse reactions. Periploca forrestii Schltr saponin (PFS) was shown to potently inhibit murine arthritis by protecting bone and cartilage injury and suppressing NF-κB activation. However, its therapeutic effect on oxazolone-induced atopic dermatitis (AD) and the underlying mechanisms on macrophage are still unclear. The AD-like dermatitis was induced by repeated oxazolone challenge to the skin of BALB/c mice in vivo. Blood and ears were biochemically or histologically processed. RT-PCR, western blotting, and ELISA were conducted to evaluate the expression of macrophage factors. Mouse bone marrow-derived macrophages (BMDMs) stimulated with lipopolysaccharide (LPS) were used as a model in vitro. PFS treatment inhibited AD-like dermatitis development. PFS downregulated epidermis thickness and cell infiltration, with histological analysis of the skin lesion. PFS alleviated plasma immunoglobulin (Ig) E, IgG2a, and IgG1 levels. PFS downregulated the expression of M1 macrophage factors, tumor necrosis factor- (TNF-) α, interleukin- (IL-) 6, monocyte chemotactic protein-1 (MCP-1), and nitric oxide synthase2 (NOS2), and M2 macrophage factors, IL-4, arginase1 (Arg1) and CD163 in AD-like skin, which were confirmed by western blot and ELISA analysis. In addition, PFS inhibited LPS-induced macrophage polarization via the inhibition of the phosphorylation of signal transducer and activator of transcription 3 (STAT3) and nuclear translocation of NF-κB p65. These results suggest that PFS exerted an antidermatitis effect against oxazolone by modulating macrophage activation. PFS administration might be useful in the treatment of AD and inflammatory skin diseases.

Anti-Inflammatory Effect of Cherry Extract Loaded in Polymeric Nanoparticles: Relevance of Particle Internalization in Endothelial Cells

This study aimed at evaluating the anti-inflammatory effect of natural cherry extract (CE), either free or encapsulated in nanoparticles (NPs) based on chitosan derivatives (Ch-der) or poly(lactic-co-glycolic acid) (PLGA), on human umbilical vein endothelial cells (HUVEC). CE from Prunus avium L. was characterized for total polyphenols, flavonoids, and anthocyanins content. CE and CE-loaded NP cytotoxicity and protective effect on lipopolysaccharide (LPS)-stressed HUVEC were tested by water-soluble tetrazolium salt (WST-1) assay. Pro- and anti-inflammatory cytokines (TNF-α, IL-6, IL-10, and PGE2) released by HUVEC were quantified by enzyme-linked immunosorbent assay (ELISA). All NP types were internalized into HUVEC after 2 h incubation and promoted the anti-inflammatory effect of free CE at the concentration of 2 µg gallic acid equivalents (GAE)/mL. CE-loaded Ch-der NPs showed the highest in vitro uptake and anti-inflammatory activity, blunting the secretion of IL-6, TNF-α, and PGE2 cytokines. Moreover, all NPs reduced the production of nitric oxide and NLRP3 inflammasome, and had a stronger anti-inflammatory effect than the major corticosteroid dexamethasone. In particular, the results demonstrate that natural CE protects endothelial cells from inflammatory stress when encapsulated in NPs based on quaternary ammonium chitosan. The CE beneficial effects were directly related with in vitro internalization of CE-loaded NPs.

Genus Periploca (Apocynaceae): A Review of Its Classification, Phytochemistry, Biological Activities and Toxicology

The genus Periploca belongs to the family Apocynaceae, which is composed of approximately ten species of plants according to incomplete statistics. Most of these plants serve as folk medicines with a long history, especially Periploca sepium and Periploca forrestii. The botanical classifications, chemical constituents, biological activities and toxicities of the genus Periploca were summarized in the literature from 1897 to early 2019. Though the botanical classification of this genus is controversial, these species are well-known to be rich sources of diverse and complex natural products-above all, cardiac steroids and C₂₁ pregnane steroids with special structures and obvious pharmacological activities. The various crude extracts and 314 isolated metabolites from this genus have attracted much attention in intensive biological studies, indicating that they are equipped with cardiotonic, anti-inflammatory, immunosuppressive, antitumor, antimicrobial, antioxidant, insecticidal and other properties. It is noteworthy that some cardiac glycosides showed hepatotoxicity and cardiotoxicity at certain doses. Therefore, in view of the medical and agricultural value of the genus Periploca, in-depth investigations of the pharmacology in vivo, the mechanisms of biological actions, and the pharmacokinetics of the active ingredients should be carried out in the future. Moreover, in order to ensure the safety of clinical medication, the potential toxicities of cardiac glycosides or other compounds should also be paid attention. This systematic review provides an important reference base for applied research on pharmaceuticals and pesticides from this genus.

Chemical profiling and the potential active constituents responsible for wound healing in Periploca forrestii Schltr

ETHNOPHARMACOLOGICAL RELEVANCE

Periploca forrestii Schltr. is a popular folk medicine in china, commonly prescribed for the treatment of rheumatoid arthritis and wounds. The present research aimed to evaluate the effects of HLG on wound healing and reveal the potential active constituents.

MATERIALS AND METHODS

The wound healing activity was assessed by proliferation of fibroblast, migration and collagen production using L929 cells. A reliable HPLC-Q-TOF-MS/MS method was constructed for the systematic identification and characterization of main components in HLG. For further clarifying the potential active ingredients responsible for wound healing, total extract was separated by D101 macroporous resin. The fraction with strongest potency on wound healing was screened out by comparing with total extract. Finally, a new quantitative method was developed for determination of four typical cardiac glycosides in HLG by LC-MS.

RESULTS

The results showed that the total extract significantly promoted proliferation of fibroblast L929 up to 168% at 50 μg/ml. It also notably enhanced L929 migration on day 2 up to 56% and stimulated collagen release (96.1 μg/ml) at 50 μg/ml. A total of 38 compounds were identified or tentatively characterized by HPLC-Q-TOF-MS/MS based on reference substances or literatures. The separation by D101 macroporous adsorption resin led to the identification of 65 ethanol eluate as the most effective fraction. The data suggested that it could markedly promote L929 growth (174% of control), accelerate wound contraction (63% on day 2) and stimulate collagen generation (103.7 μg/ml) at 50 μg/ml, all of which were comparable to those of total extract. Interestingly, the HPLC-Q-TOF-MS/MS analysis revealed that the 65 ethanol fraction was mainly composed of cardiac glycosides. Finally, the new quantitative method was successfully utilized for detection of four typical cardiac glycosides in HLG, showing good performance in terms of analytical methodology.

CONCLUSION

The present study identified the cardiac glycosides as potential active constituents associated with wound healing and might afford a chemical foundation for preparation development of crude drug and quality evaluation of relevant products.

In Vivo and In Vitro Anti-Arthritic Effects of Cardenolide-Rich and Caffeoylquinic Acid-Rich Fractions of Periploca forrestii

Periploca forrestii Schltr. (P. forrestii) is a species used in Traditional Chinese Medicine (TCM) known as “Miao medicine”, and has a long history of use in the treatment of rheumatism, rheumatoid arthritis (RA), and joint pain. The present study aimed to evaluate the anti-arthritis effects of the cardenolide-rich and caffeoylquinic acid-rich fractions (CDLFs and CQAFs) of P. forrestii in collagen-induced arthritic (CIA) rats, and defined the mechanisms of therapeutic action in MH7A cells treated with TNF-α. Serum rheumatoid factor (RF), TNF-α, IL-6, IL-1β, PGE₂, NO, SOD, and MDA were determined by ELISA or other commercially assay kits. Histopathological changes in ankle joint tissues were examined. The mRNA expressions of IL-1β, IL-6, COX-2, and iNOS in MH7A cells were measured by qRT-PCR assays. In addition, the expressions of iNOS, COX-2, and p65 proteins, and the phosphorylation of IκBα, p38, ERK_1/2, and JNK proteins in MH7A cells were analyzed by Western blot. The results showed that CDLF and CQAF could suppress the paw swelling in CIA rats at different doses (125 mg/kg, 250 mg/kg, and 500 mg/kg). Histopathological examination suggests that the CDLF and CQAF significantly relieved the damage of the structure of the ankle joint in CIA rats. In addition, serum RF, TNF-α, IL-6, IL-1β, PGE₂, NO, and MDA were decreased, along with increased activity of serum SOD. Furthermore, CDLF and CQAF downregulated the expressions of IL-1β, IL-6, COX-2, iNOS, and p65, and inhibited the phosphorylation of IκBα, p38, ERK_1/2, and JNK in MH7A cells treated with TNF-α. These findings demonstrated that both CDLF and CQAF exhibited anti-arthritic activity, which might be associated with their inhibitory effects on the NF-κB and MAPK signaling pathways.

Kobophenol A Isolated from Roots of Caragana sinica (Buc'hoz) Rehder Exhibits Anti-inflammatory Activity by Regulating NF-κB Nuclear Translocation in J774A.1 Cells

Kobophenol A (KPA) is a biologically active natural compound isolated from the roots of Caragana sinica (Buc'hoz) Rehder (C. sinica). However, the anti-inflammatory effects of KPA have not been reported. This study aims to find out whether KPA isolated from roots of C. sinica can act as a potential substance on inflammation and analyze the molecular mechanism using the lipopolysaccharide (LPS)-stimulated J774 A.1 macrophage cell line. We showed that KPA treatment significantly suppressed the production of nitric oxide (NO) by inhibiting inducible nitric oxide synthase (iNOS) expression in a dose-dependent manner without cytotoxicity. In the KPA also inhibited pro-inflammatory cytokine gene expression and production, such as interleukin-1β (IL-1β) and interleukin-6 (IL-6) in LPS-stimulated J774 A.1 cells. As continuing study on the mechanisms involved, we confirmed that these effects of KPA were related to the inhibition of nuclear factor-κB (NF-κB) pathway including the suppression of IκB kinase α/β (IKKα/β) phosphorylation and translocation of NF-κB into the nucleus. Taken together, the present study is the first to demonstrate that KPA isolated from C. sinica suppresses the expression of inflammatory mediators and cytokines by inhibiting NF-κB nuclear translocation in LPS-stimulated J774 A.1 macrophages. KPA may be a potential candidate for the treatment of inflammatory diseases in the future.