Simultaneous quantification of Kirenol and ent-16β,17-dihydroxy-kauran-19-oic acid from Herba Siegesbeckiae in rat plasma by liquid chromatography-tandem mass spectrometry and its application to pharmacokinetic studies

Research progress in arthritis treatment with the active components of Herba siegesbeckiae

Arthritis is a group of diseases characterized by joint pain, swelling, stiffness, and limited movement. Osteoarthritis, rheumatoid arthritis, and gouty arthritis are the most common types of arthritis. Arthritis severely affects the quality of life of patients and imposes a heavy financial and medical burden on their families and society at large. As a widely used traditional Chinese medicine, Herba siegesbeckiae has many pharmacological effects such as anti-inflammatory and analgesic, anti-ischemic injury, cardiovascular protection, and hypoglycemic. In addition, it has significant therapeutic effects on arthritis. The rich chemical compositions of H. siegesbeckiae primarily include diterpenoids, sesquiterpenoids, and flavonoids. As one of the main active components of H. siegesbeckiae, kirenol and quercetin play a vital role in reducing arthritis symptoms. In the present study, the research progress in arthritis treatment with the active components of H. siegesbeckiae is reviewed.

Kirenol: A Potential Natural Lead Molecule for a New Drug Design, Development, and Therapy for Inflammation

Kirenol, a potential natural diterpenoid molecule, is mainly found in Sigesbeckia species. Kirenol has received a lot of interest in recent years due to its wide range of pharmacological actions. In particular, it has a significant ability to interact with a wide range of molecular targets associated with inflammation. In this review, we summarise the efficacy and safety of kirenol in reducing inflammation, as well as its potential mechanisms of action and opportunities in future drug development. Based on the preclinical studies reported earlier, kirenol has a good therapeutic potential against inflammation involved in multiple sclerosis, inflammatory bowel disorders, diabetic wounds, arthritis, cardiovascular disease, bone damage, and joint disorders. We also address the physicochemical and drug-like features of kirenol, as well as the structurally modified kirenol-derived molecules. The inhibition of pro-inflammatory cytokines, reduction in the nuclear factor kappa-B (NF-κB), attenuation of antioxidant enzymes, stimulation of heme-oxygenase-1 (HO-1) expression, and nuclear factor erythroid 2-related factor 2 (Nrf2) phosphorylation are among the molecular mechanisms contributing to kirenol's anti-inflammatory actions. Furthermore, this review also highlights the challenges and opportunities to improve the drug delivery of kirenol for treating inflammation. According to the findings of this review, kirenol is an active molecule against inflammation in numerous preclinical models, indicating a path to using it for new drug discovery and development in the treatment of a wide range of inflammations.

Kirenol: A promising bioactive metabolite from siegesbeckia species: A detailed review

ETHNOPHARMACOLOGICAL RELEVANCE

Kirenol (Kr) is an ent-pimarane type diterpenoid that has been reported from Siegesbeckiaorientalis, S. pubescens, and S. glabrescens (family Asteraceae). These plants have been used traditionally for treating various ailments such as hypertension, neurasthenia, rheumatoid arthritis, asthma, snakebites, allergic disorders, paralysis, soreness, cutaneous disorders, rubella, menstrual disorders, numbness of limbs, dizziness, headache, and malaria. Importantly, in recent years, Kr has received great attention due to its diversified pharmacological activities.

AIM OF THE STUDY

The current work aims to give an overview on the reported pharmacological activities of Kr. Furthermore, the findings regarding its methods for extraction, quantitative analysis, purification, pharmacokinetics, pharmaceutical and food preparations, biosynthesis, identification, semisynthetic analogues, and toxicity are highlighted to provide a reference and perspective for its further investigation.

METHODS

Electronic databases including ScienceDirect, Web of Knowledge, SCOPUS, Wiley Online Library, Taylor & Francis, PubMed, Springer, JACS, and Google Scholar were searched up to the beginning of 2021 to identify the reported studies.

RESULTS

A total of 93 articles have been reviewed. The reported data suggested that Kr possessed various bioactivities including cytotoxic, apoptotic, anticancer, anti-inflammatory, cardio-protective, anti-photo-aging, anti-adipogenic, antimicrobial, muscle function improvement, fracture and wound healing, and anti-arthritic. In addition, studies revealed that the antioxidative and anti-inflammatory activities of Kr may mediate many of its therapeutic potentials as confirmed by several in-vitro and in-vivo studies.

CONCLUSION

This review provides an updated summary of the recent studies on Kr, including methods for extraction, quantitative analysis, purification, pharmacokinetics, pharmaceutical and food preparations, biosynthesis, and identification, as well as semisynthetic analogues, pharmacological activities, and toxicity. Thus, this work can provide useful considerations for planning and design future research on Kr.

Protective Effects of Kirenol against Lipopolysaccharide-Induced Acute Lung Injury through the Modulation of the Proinflammatory NFκB Pathway and the AMPK2-/Nrf2-Mediated HO-1/AOE Pathway

Acute lung injury (ALI) is an acute and life-threatening inflammatory disease of the lung parenchyma that is associated with high mortality worldwide. No therapeutic strategies have been developed for the mitigation of the proinflammatory response that characterizes ALI. Kirenol has anti-inflammatory, antiarthritic, and immunoregulatory effects. In the present study, we investigated the protective effects of kirenol against lipopolysaccharides (LPS)-induced ALI in mice. Kirenol reduced the LPS-induced histopathology changes involving edema and thickening of the interstitial or alveolar walls, infiltration of leukocytes, formation of hyaline membrane. Pretreatment with kirenol reduced leukocytes infiltration in bronchoalveolar lavage fluid (BALF), the alveolar-capillary barrier disruption and lipid peroxidation in lung tissues induced by LPS. Kirenol significantly inhibited the secretion of cytokines, IL-1β, IL6, and TNFα, into the BALF of the mice with LPS-induced ALI through NFκB activation. Moreover, kirenol attenuated the downregulation of the antioxidant enzymes, superoxide dismutase, glutathione peroxidase, and catalase that was induced by LPS. HO-1 expression and the phosphorylation of Nrf2 and AMPK2 were also induced by kirenol. The results indicate that kirenol can be developed as a treatment strategy for ALI, and its effects are induced through the inhibition of the NF-κB proinflammatory pathway and promotion of AMPK2/Nrf2-mediated HO-1 and antioxidant enzymes (AOE) activation.

A sensitive HPLC-FLD method for the quantification of 6-O-demethylmenisporphine isolated from Menispermi Rhizoma in rat plasma

Background

To investigate the pharmacokinetics of 6-O-demethylmenisporphine, an oxoisoaporphine alkaloid with significant anti-tumor activities and isolated from Menispermi Rhizoma, a novel and sensitive HPLC assay was established for 6-O-demethylmenisporphine quantification in rat plasma.

Methods

Peak responses were detected by a highly selective and sensitive fluorescence detector with 426-nm excitation and 514-nm emission wavelengths. Curcumin was employed as the internal standard (IS). A Capcell Pak C18 column (150 mm × 4.6 mm i.d., 5 μm) and an isocratic elution procedure with a flow rate of 1.0 mL/min were used to exclude the endogenous interfering substance. Acetonitrile-water (68:32, v/v) containing 1% formic acid was employed as mobile phase. A 7-point calibration curve that covered the concentration range of 10–2500 ng/mL was constructed.

Results

A good linearity was observed with a correlation coefficient (r) of 0.9993. The lower limit of quantification for 6-O-demethylmenisporphine was 10 ng/mL. The mean recoveries of analyte in rat plasma exceeded 80.5%. The precision at four concentration levels was within 11.3% and the accuracy ranged from − 7.6 to 6.7%.

Conclusion

Using this new HPLC-FLD method, the investigation of plasma samples from rats following oral dosing of neat compound and Menispermi Rhizoma extract was successfully conducted. The results will provide a reference for the evaluation of preclinical safety of 6-O-demethylmenisporphine.

[Kirenol relieves dextran sulfate sodium-induced ulcerative colitis in mice by inhibiting inflammatory cytokines and inducing CD4+ T lymphocyte apoptosis]

OBJECTIVE

To investigate whether kirenol, the major pharmacologically active compound of the Chinese medicinal herb Herba Siegesbeckiae, can protect mice from dextran sulfate sodium (DSS)-induced ulcerative colitis (UC).

METHODS

C57BL/6 mice with or without kirenol pretreatment were treated with DSS in drinking water for 7 days to induce UC. The symptoms of UC including weight loss, diarrhea and bloody stool were observed daily and graded using the disease activity index (DAI). Colon injury of the mice was assessed by measuring the length of the colon and HE staining of the colon tissue. The levels of inflammatory cytokines produced by the mesenteric lymph nodes (MLNs) lymphocytes were measured using enzyme-linked immunosorbent assay; the apoptosis of the lymphocytes and CD4⁺ T cells was analyzed using flow cytometry.

RESULTS

The mice receiving pretreatment with kirenol showed obviously ameliorated symptoms of UC and milder pathological changes in the colon as compared with the control mice. Kirenol treatment significantly down-regulated the secretion of IFN-γ, IL-17A, IL-6 and TNF-α by the MLNs lymphocytes and increased the apoptosis of lymphocytes, especially CD4⁺ T cells in the DSS-treated mice.

CONCLUSIONS

Kirenol can protect against T cell-mediated colon injury in DSS-treated mice possibly by suppressing the secretion of inflammatory mediators and inducing apoptosis of the inflammatory lymphocytes.

Kirenol Inhibits the Function and Inflammation of Fibroblast-like Synoviocytes in Rheumatoid Arthritis in vitro and in vivo

Kirenol is a diterpenoid extracted from the Chinese herbal medicine Siegesbeckiae. Siegesbeckiae has been used to treat Rheumatoid arthritis (RA) in China for several centuries. RA is characterized by the proliferation of synoviocytes in inflamed synovia, as well as by their expression of inflammatory cytokines. In the present study, we found that Kirenol inhibited the migration, invasion, and proinflammatory of IL-6 secretion of RA-associated synovial fibroblasts (FLS) at a concentration of 100–200 μg/ml in vitro. Proinflammatory cytokines production and synovium hyperplasia and cartilage erosion were also inhibited in a collagen-induced arthritis (CIA) mouse model upon Kirenol treatment. Together, our results thus confirm that Kirenol has potent therapeutic efficacy in RA owing to its ability to suppress negative FLS activities.

Kirenol attenuates experimental autoimmune encephalomyelitis by inhibiting differentiation of Th1 and th17 cells and inducing apoptosis of effector T cells

Experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis (MS), is characterized by CNS demyelination mediated by autoreactive T cells. Kirenol, a biologically active substance isolated from Herba Siegesbeckiae, has potent anti-inflammatory activities. Here we investigated effects of kirenol on EAE. Kirenol treatment markedly delayed onset of disease and reduced clinical scores in EAE mice. Kirenol treatment reduced expression of IFN-γ and IL-17A in the serum and proportion of Th1 and Th17 cells in draining lymph nodes. Priming of lymphocytes was reduced and apoptosis of MOG-activated CD4+ T cells was increased in kirenol treated EAE mice. Kirenol treatment of healthy animals did not affect the lymphocytes in these non-immunized mice. Further in vitro studies showed that kirenol inhibited viability of MOG-specific lymphocytes and induced apoptosis of MOG-specific CD4+ T cells in a dose- and time-dependent manner. Kirenol treatment upregulated Bax,downregulated Bcl-2,and increased activation of caspase-3 and release of cytochrome c, indicating that a mitochondrial pathway was involved in kirenol induced apoptosis. Moreover, pretreatment with either a pan-caspase inhibitor z-VAD-fmk or a more specific caspase 3 inhibitor Ac-DEVD-CHO in lymphocytes reduced kirenol induced apoptosis. Our findings implicate kirenol as a useful agent for the treatment of MS.

Kirenol inhibits adipogenesis through activation of the Wnt/β-catenin signaling pathway in 3T3-L1 adipocytes

Kirenol, a natural diterpenoid compound, has been reported to possess anti-oxidant, anti-inflammatory, anti-allergic, and anti-arthritic activities; however, its anti-adipogenic effect remains to be studied. The present study evaluated the effect of kirenol on anti-adipogenesis through the activation of the Wnt/β-catenin signaling pathway. Kirenol prevented intracellular lipid accumulation by down-regulating key adipogenesis transcription factors [peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding proteins α (C/EBPα), and sterol regulatory element binding protein-1c (SREBP-1c)] and lipid biosynthesis-related enzymes [fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC)], as well as adipocytokines (adiponectin and leptin). Kirenol effectively activated the Wnt/β-catenin signaling pathway, in which kirenol up-regulated the expression of low density lipoprotein receptor related protein 6 (LRP6), disheveled 2 (DVL2), β-catenin, and cyclin D1 (CCND1), while it inactivated glycogen synthase kinase 3β (GSK3β) by increasing its phosphorylation. Kirenol down-regulated the expression levels of PPARγ and C/EBPα, which were up-regulated by siRNA knockdown of β-catenin. Overall, kirenol is capable of inhibiting the differentiation and lipogenesis of 3T3-L1 adipocytes through the activation of the Wnt/β-catenin signaling pathway, suggesting its potential as natural anti-obesity agent.