Simultaneous determination of seven major diterpenoids in Siegesbeckia pubescens Makino by high-performance liquid chromatography coupled with evaporative light scattering detection

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.

Simultaneous separation and determination of three diterpenoids in Euphorbia lathyris L. and its formulations by hydrophobic interaction electrokinetic chromatography

In this study, a hydrophobic interaction electrokinetic chromatography method has been developed for simultaneous separation and determination of three diterpenoids in Euphorbia lathyris L.: Euphorbia factors L₁ , L₂ , and L₃ . After optimization of separation conditions, the electrolyte solution was 5.0 mM ammonium acetate buffer containing 30 mM sodium dodecyl sulfate in a 60% v/v methanol (pH 6.86), 25 kV of electric field across the capillary was applied at 25°C, and the detection wavelength was at 280 nm. Under optimum conditions, good linearity was achieved with correlation coefficients from 0.9945 to 0.9995. The limits of detection were 2.5, 7.5, and 5.6 μg/mL, and the limits of quantitation were 8.8, 23.9, and 15.3 μg/mL, respectively. Excellent accuracy and precision were obtained. Recoveries of the analytes varied from 98.5 to 103.8%. The established method was novel, simple, and rapid, and it was validated and confirmed to be applicable for the determination of the active ingredients in a quality control analysis.

An ethanolic extract of the aerial part of Siegesbeckia orientalis L. inhibits the production of inflammatory mediators regulated by AP-1, NF-κB and IRF3 in LPS-stimulated RAW 264.7 cells

Herba Siegesbeckiae (HS, the dried aerial part of Siegesbeckia orientalis L.) is a commonly used traditional Chinese medicinal herb for treating inflammatory diseases. HS has been reported to exert anti-inflammatory effects by inhibiting the MAPKs and NF-κB pathways, the downstream effectors of TLR4 signalling. This study aims to further investigate the involvement of TLR4 signalling cascades in the effects of an ethanolic extract of HS (HS for short) on inflammatory mediators in murine macrophages. HS was extracted using 50% ethanol. Lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages were used as the cell model. ELISA was used to detect cytokine/chemokine secretion. Real time-PCR and immunoblotting were used to examine mRNA and protein levels, respectively. We observed that HS dose-dependently inhibited the secretion of PGE₂, MCP-1, MIP-1α and RANTES, and down-regulated mRNA levels of iNOS, COX-2, IL-1β, IL-6, TNF-α, mPGES-1, MCP-1, MIP-1α and RANTES in LPS-stimulated RAW264.7 cells. HS did not affect the protein levels of TAK1, TBK1, PI3K, Akt, IKK, c-Jun, c-Fos and IRF3, while, dose-dependently decreased levels of their phosphorylated forms. The protein levels of IRAK1 and IRAK4 were upregulated, while those of TRAF6 and TRAF3 were downregulated by HS. Moreover, the nuclear protein levels of AP-1, NF-κB and IRF3 were dose-dependently decreased by HS. These results indicate that suppression of the IRAK4/MAPKs/AP-1, IRAK4/MAPKs/NF-κB, IRAK4/PI3K/NF-κB and TRAF3/TBK1/IRF3 pathways is associated with the inhibitory effects of HS on inflammatory mediators in LPS-stimulated RAW264.7 cells. This study provides a pharmacological basis for the clinical application of this herb in the treatment of inflammatory disorders.

Siegesbeckia pubescens Makino inhibits Pam3CSK4-induced inflammation in RAW 264.7 macrophages through suppressing TLR1/TLR2-mediated NF-κB activation

Background

Siegesbeckia pubescens Makino (SP) is one of the important plant origins for the anti-inflammatory Chinese herbal medicine of Siegesbeckiae Herba. The current investigations indicated that the anti-inflammatory effects of SP were associated with the toll-like receptors (TLRs)-mediated nuclear factor-κB (NF-κB) and the mitogen-activated protein kinase (MAPK) signaling pathways.

Methods

Raw 264.7 macrophages were pretreated with the 50% ethanol extract of SP (SPE, 50–200 µg/mL) and then co-treated with Pam₃CSK₄ (200 ng/mL) for another 12 h. The inhibitory effect of SPE on Pam₃CSK₄-stimulated NO release and post-inflammatory cytokines secretions were determined using Griess reagent and Elisa kits, respectively. The influence of SPE on NF-κB and MAPKs signaling relevant proteins was measured by Western blotting analysis, while the intracellular nitric oxide (NO) generation and NF-κB/p65 nuclear translocation were determined using Leica TCS SP8 laser scanning confocal microscope. Moreover, the effect of SPE on luciferase reporter gene in NF-κB-luc DNA transfected raw 264.7 cells was determined using the Dual-Glo luciferase assay system kit.

Results

SPE dose-dependently (50–200 µg/mL) attenuated Pam₃CSK₄-induced NO release, post-inflammatory cytokines (IL-6, TNF-α and MCP-1) secretions and intracellular NO generation in raw 264.7 cells. Biologically, SPE suppressed Pam₃CSK₄-induced expressions of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), phosphorylation of NF-κB/p65 and IκBα, but did not significantly show effect on the proteins involved in MAPKs signaling (p38, ERK and JNK). The results were further confirmed by NF-κB-luc reporter gene assay and p65 nuclear translocation assay.

Conclusions

In conclusion, SPE ameliorated Pam₃CSK₄-induced inflammation in raw 264.7 cells through suppressing TLR 1/2-mediated NF-κB activation.

Electronic supplementary material

The online version of this article (10.1186/s13020-018-0193-x) contains supplementary material, which is available to authorized users.

Neuroprotective Effects of Sigesbeckia pubescens Extract on Glutamate-Induced Oxidative Stress in HT22 Cells via Downregulation of MAPK/caspase-3 Pathways

Sigesbeckia pubescens (SP) is a traditional Chinese medicine, possessing antioxidant and anti-inflammatory activities. In this study, we evaluate the neuroprotective activities of SP extract on glutamate-induced oxidative stress in HT22 cells and the molecular mechanism underlying neuroprotection. We applied 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), crystal violet, reactive oxygen species (ROS), lactate dehydrogenase (LDH), quantitative real-time polymerase chain reaction (qPCR), and western blot analyses for assessing the neuroprotective effects of SP extract. The experimental study revealed that SP considerably increased the cell viability, and reduced the oxidative stress promoted ROS and LDH generation in HT22 cells in a dose-dependent manner. Additionally, the morphology of HT22 cells was effectively improved by SP. Upregulated gene expressions of mitogen-activated protein kinase (MAPK) were markedly attenuated by SP. Similarly, SP notably suppressed the ROS-mediated phosphorylation of MAPK (pERK1/2, pJNK, and pp38) cascades and activation of apoptotic factor caspase-3 signaling pathway that overall contributed to the neuroprotection. Taken together, SP may exert neuroprotective effects via alteration of MAPK and caspase-3 pathways under oxidative stress condition. Therefore, SP is a potential agent for preventing oxidative stress-mediated neuronal cell death.

Determination of lupenone and β-sitosterol in Rhizoma Musae by UPLC with DAD and ELSD

Rhizoma Musae has been used for centuries in Miao medicine practice in China, and it usually uses for treating diabetes and bruises. In this study, lupenone and β-sitosterol in Rhizoma Musae were separated by reversed-phase ultra-performance liquid chromatography (RP-UPLC) and simultaneously detected by a diode array detector (DAD) and an evaporative light scattering detector (ELSD) using methanol and 0.1% aqueous acetic acid (100 : 4, v/v) as a mobile phase in 20 min. The flow rate of 0.1 mL/min was set with isocratic, the temperature of column compartment maintained at 50°C and ultraviolet detection set at 206 nm wavelength. The injection volume was 1.0 µL. The parameter for the ELSD was set to a probe temperature of 45°C, and the nebulizer for nitrogen gas was adjusted to 1.5 L/min. The RP-UPLC method was validated for accuracy, precision, limit of detection and limit of quantification. It applied to the quantification of the active chemical constituents of Rhizoma Musae, and results indicated that both DAD and ELSD were suitable for the determination of lupenone and β-sitosterol, and the DAD has a better sensitivity than the ELSD.

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

A rapid and specific liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method was developed for the simultaneous determination of two active diterpenoids: Kirenol and ent-16β,17-dihydroxy-kauran-19-oic acid (DHKA) from Herba Siegesbeckiae in rat plasma using osthole as an internal standard (IS). Plasma sample pretreatment involved a one-step liquid-liquid extraction with ethyl acetate. Chromatographic separation was performed on a Waters Symmetry C18 column (2.1mm×100mm, 3.5μm) with isocratic elution using methanol-5mmol/L aqueous ammonium acetate (80:20, v/v) as the mobile phase at a flow rate of 0.2mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring (MRM) mode under positive and negative electrospray ionization. The calibration curves were linear over the range of 50.0-25,000ng/mL for Kirenol, and 25.0-12,500ng/mL for DHKA. The extraction recoveries of the two analytes and the IS were all over 85%. The intra- and inter-day precision (relative standard deviation) values were less than 16.8% and the accuracy (relative error) ranged from -10.7 to 10.6% at four quality control levels. The validated method was successfully applied to a comparative pharmacokinetic study of the two diterpenoids in rat plasma after intragastric administration of Kirenol, DHKA and Herba Siegesbeckiae extract. The results showed that there were obvious differences between the pharmacokinetic behaviors after oral administration of Herba Siegesbeckiae extract compared with each of the substances alone.