Three diterpenes from Leonurus japonicus houtt protect primary cultured rat cortical cells from glutamate-induced toxicity

Leonurus japonicus Houtt. modulates neuronal apoptosis in intracerebral hemorrhage: Insights from network pharmacology and molecular docking

ETHNOPHARMACOLOGICAL RELEVANCE

Leonurus japonicus Houtt. (Labiatae), commonly known as Chinese motherwort, is a herbaceous flowering plant that is native to Asia. It is widely acknowledged in traditional medicine for its diuretic, hypoglycemic, antiepileptic properties and neuroprotection. Currently, Leonurus japonicus (Leo) is included in the Pharmacopoeia of the People's Republic of China. Traditional Chinese Medicine (TCM) recognizes Leo for its myriad pharmacological attributes, but its efficacy against ICH-induced neuronal apoptosis is unclear.

AIMS OF THE STUDY

This study aimed to identify the potential targets and regulatory mechanisms of Leo in alleviating neuronal apoptosis after ICH.

MATERIALS AND METHODS

The study employed network pharmacology, UPLC-Q-TOF-MS technique, molecular docking, pharmacodynamic studies, western blotting, and immunofluorescence techniques to explore its potential mechanisms.

RESULTS

Leo was found to assist hematoma absorption, thus improving the neurological outlook in an ICH mouse model. Importantly, molecular docking highlighted JAK as Leo's potential therapeutic target in ICH scenarios. Further experimental evidence demonstrated that Leo adjusts JAK1 and STAT1 phosphorylation, curbing Bax while augmenting Bcl-2 expression.

CONCLUSION

Leo showcases potential in mitigating neuronal apoptosis post-ICH, predominantly via the JAK/STAT mechanism.

Diterpene synthases from Leonurus japonicus elucidate epoxy-bridge formation of spiro-labdane diterpenoids

Spiro-9,13-epoxy-labdane diterpenoids are commonly found in Leonurus species, particularly in Leonurus japonicus Houtt., which is a medicinal herb of long-standing use in Asia and in which such spiro-heterocycles are present in at least 38 diterpenoids. Here, through generation of a transcriptome and functional characterization of six diterpene synthases (diTPSs) from L. japonicus, including three class II diTPSs (LjTPS1, LjTPS3, and LjTPS4) and three class I diTPSs (LjTPS5, LjTPS6, and LjTPS7), formation of the spiro-9,13-epoxy-labdane backbone was elucidated, along with identification of the relevant diTPSs for production of other labdane-related diterpenes. Similar to what has been found with diTPSs from other plant species, while LjTPS3 specifically produces the carbon-9 (C9) hydroxylated bicycle peregrinol diphosphate (PPP), the subsequently acting LjTPS6 yields a mixture of four products, largely labda-13(16),14-dien-9-ol, but with substantial amounts of viteagnusin D and the C13-S/R epimers of 9,13-epoxy-labda-14-ene. Notably, structure-function analysis identified a critical residue in LjTPS6 (I420) in which single site mutations enable specific production of the 13S epimer. Indeed, extensive mutagenesis demonstrated that LjTPS6:I420G reacts with PPP to both specifically and efficiently produce 9,13S-epoxy-labda-14-ene, providing a specialized synthase for further investigation of derived diterpenoid biosynthesis. The results reported here provide a strong foundation for future studies of the intriguing spiro-9,13-epoxy-labdane diterpenoid metabolism found in L. japonicus.

Leojaponin inhibits NLRP3 inflammasome activation through restoration of autophagy via upregulating RAPTOR phosphorylation

ETHNOPHARMACOLOGICAL RELEVANCE

Duan Teng Yimu decoction is a Chinese herbal medicine compound with proven therapeutic effects on inflammasome-related diseases, such as rheumatoid arthritis. This decoction consists of three Chinese herbal medicines, including Leonurus japonicus (L. japonicus), which promotes the blood circulation and exhibits detumescence activity, traditionally curing gynecologic and inflammasome diseases.

AIM OF THE STUDY

To explore the anti-inflammasome activity and the underlying mechanisms of action of the compounds from L. japonicus.

MATERIALS AND METHODS

A series of compounds were isolated from L. japonicus. Their anti-inflammasome activities were evaluated in macrophages that were co-stimulated by lipopolysaccharide (LPS) and NLRP3 inflammasome inducers. NLRP3 inflammasome formation and apoptosis speck like containing a CARD (ASC) oligomerization were evaluated by immunofluorescent microscopy and Western blot analysis. The regulation of autophagy after treatment of this compound was also evaluated. Lastly, in vivo activity of Leojaponin was analyzed in a mouse acute gouty arthritis model.

RESULTS

Here we show that Leojaponin, a diterpenoid compound from L. japonicus, suppressed lactate dehydrogenase and IL-1β release in Nigericin-stimulated macrophages in a pyroptosis model. Leojaponin inhibits NLRP3 inflammasome activation in both J774A.1 cells and bone marrow-derived macrophages in a dose dependent manner. Moreover, Leojaponin suppressed NLRP3-mediated ASC specks formation and ASC oligomerization. These activities of Leojaponin depend on restoration of autophagy via promoting RAPTOR phosphorylation. Furthermore, Leojaponin ameliorated monosodium urate (MSU)-induced acute gouty arthritis in vivo.

CONCLUSION

Our findings suggest that Leojaponin inhibits NLRP3 inflammasome activation through enhancing autophagy via RAPTOR phosphorylation, thereby highlighting Leojaponin as a potent drug for inflammasome-related diseases.

Structurally Diverse Labdane Diterpenoids from Leonurus japonicus and Their Anti-inflammatory Properties in LPS-Induced RAW264.7 Cells

A phytochemical study on the aerial parts of Leonurus japonicus led to the isolation and identification of 38 labdane diterpenoids, including 18 new (1, 2, 11, 12, 16-21, 24, 30-34, 37, 38) and 20 known (3-10, 13-15, 22, 23, 25-29, 35, 36) analogues. Their structures were elucidated based on physical data analysis, including 1D and 2D NMR, HRMS, UV, IR, and X-ray diffraction. The structure of the known compound 4 was confirmed by single-crystal X-ray diffraction data. These compounds can be divided into furanolabdane (1-10), tetrahydrofuranolabdane (11-15), lactonelabdane (16-23), labdane (24-29), and seco-labdane (30-38) type diterpenoids. All compounds were screened by lipopolysaccharide (LPS)-induced nitric acid (NO) production in RAW264.7 cells to evaluate anti-inflammatory effects. Compounds 1, 5, 10-13, 16-19, 31-33, and 38 inhibited NO production with IC₅₀ values lower than 50 μM, with compound 30 being the most active, with an IC₅₀ value of 3.9 ± 1.7 μM. Further studies show that compound 30 inhibits pro-inflammatory cytokine production and IKK α/β phosphorylation and restores the IκB expression levels in the NF-κB signaling pathway.

Immunomodulatory and antitumour bioactive labdane diterpenoids from Leonurus japonicus

OBJECTIVES

Two labdane diterpenoids, leojapone B and heteronone B, were isolated from Leonurus japonicus Houtt., and their biological activity were evaluated in this study.

METHODS

Human and mouse cancer cells, human peripheral blood mononuclear cells (PBMCs) and mouse macrophages (RAW264.7 cells) were used to evaluate the activity of leojapone B and heteronone B, while the in vivo effects of leojapone B were further examined in Lewis Lung Cancer tumour-bearing mice.

KEY FINDINGS

In vitro studies showed that leojapone B selectively inhibited the proliferation of lung cancer cells, and both leojapone B and heteronone B inhibited the production of pro-inflammatory cytokines in activated PBMCs. In tumour-bearing mice model, lung tumours were reduced in size in mice treated with intraperitoneal injections of leojapone B at 20 and 30 mg/kg for 14 days. The population ratio of CD4⁺ /CD8⁺ T cells in mouse spleens was found to be increased, while regulatory T cells were decreased after leojapone B treatment.

CONCLUSIONS

The inhibitory effects of leojapone B in mouse lung tumours were demonstrated for the first time in this study. The immunomodulatory activity of heteronone B were also demonstrated. Our findings indicated that both leojapone B and heteronone B may act as active components in L. japonicus.

Labdane-Type Diterpenoids from Leonurus japonicus and Their Plant-Growth Regulatory Activity

Thirteen new labdane-type diterpenoids 1-6, 9-11, 13, 14, 18, and 19 and seven known ones were isolated from the aerial parts of Leonurus japonicus. Compounds 1-5 represent rare examples of labdane-type diterpenoids, of which compounds 1-4 carry an N-chain linked at C-7 in their B-ring and compound 5 featured an α,β-unsaturated-γ-lactam moiety. The structures and absolute configurations of these new diterpenoids were characterized by a combination of spectroscopic techniques, X-ray crystallography, electronic circular dichroism, and calculated specific rotations. The plant-growth regulatory activity of these compounds on the growth of the roots and shoots of Lactuca sativa and Lolium perenne seedlings were evaluated. Compound 3 showed a broad-spectrum inhibitory activity with the inhibition rates ranging from 60 to 83.5% at a concentration of 200 μg/mL, which were as active as those of glyphosate. Compound 8 had a selective inhibitory activity against the growth of the roots of L. perenne seedlings with an inhibition rate of 81.7%. However, compounds 11 and 16 exhibited significant stimulation effects on the roots of L. sativa with stimulation rates of 59.8 and 65.3%, respectively. In addition, compounds 3 and 8 exhibited inhibitory effects on the germination of L. perenne seeds.

New diterpenoids isolated from Leonurus japonicus and their acetylcholinesterase inhibitory activity

Three new labdane diterpenoids, leojaponicone A (1), isoleojaponicone A (2) and methylisoleojaponicone A (3), were isolated from the herb of Leonurus japonicus. The chemical structures of these secondary metabolites were elucidated on the basis of 1D and 2D NMR, including HMQC, and HMBC spectroscopic techniques. All the new compounds were tested in vitro for their acetylcholinesterase and α-glucosidase inhibitory activity. Compounds 1-3 exhibited low inhibitory effects on α-glucosidase with respect to acarbose and exhibited high inhibitory effects on acetylcholinesterase with respect to huperzine A.

Leojaponic acids A and B, two new homologous terpenoids, isolated from Leonurus japonicus

The present study aimed at isolation and purification of the bioactive terpenoids from the herb of Leonurus japonicus by chromatographic separations such as silica gel, sephadex LH-20 and C18 reversed phase silica gel, as well as preparative HPLC. As a result, leojaponic acids A (1, C17H24O4) and B (2, C18H26O4), two homologous terpenoids, together with (-)-loliolide (3), 1-(3-ethylphenyl) ethane-1, 2-diol (4) and dibutyl phthalate (5), were isolated from the EtOH extract of L. japonicus. All the chemical structures of the isolates were elucidated on the basis of 1D and 2D NMR analyses. Compounds 1 and 2 were new terpenoids, and Compounds 3 and 4 were isolated and identified for the first time from this plant. In addition, the α-glucosidase and tyrosinase inhibitory activity of the new compounds were evaluated.

Isoleojaponin, a new Halimane diterpene isolated from Leonurus japonicus

Leojaponin (2), a labdane diterpene, was isolated from the EtOH extract of the herb of Leonurus japonicus together with a new halimane diterpene named isoleojaponin (1). Isoleojaponin has a new diterpene skeleton with a unique cross-conjugated α,β-unsaturated ketone system, Their structures were elucidated by physical and spectroscopic analysis, and the relative configuration of the chiral C-9 carbon was determined by a computational method, and analysis of its possible biogenesis pathways.

Leonurus japonicus Houtt.: ethnopharmacology, phytochemistry and pharmacology of an important traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Leonurus japonicus Houtt. (Labiatae), commonly called Chinese motherwort ([Symbol: see text]), is an herbaceous flowering plant native to Asia. For thousands of years in China, the aerial part of Leonurus japonicus has been used to treat menoxenia, dysmenorrhea, amenorrhea, lochia, edema of the body, oliguresis, sores, ulcerations and other diseases in women. Now, Leonurus japonicus is listed in the Pharmacopoeia of the People's Republic of China. The present paper reviewed the ethnopharmacology, phytochemistry, biological actions and toxicology of Leonurus japonicus.

MATERIALS AND METHODS

Information on Leonurus japonicus was gathered via the Internet (using Elsevier, ACS, Medline Plus, CNKI, VIP, Web of Science, Google Scholar and Baidu Scholar) and libraries.

RESULTS

Approximately 140 chemical compounds have been isolated from Leonurus japonicus, and the major components have been determined to be alkaloids, diterpenes and flavones. Among these active compounds, the effects of leonurine and stachydrine have been widely investigated. The primary active components in Leonurus japonicus possess wide pharmacological actions, such as effects on the uterus as well as cardioprotective, anti-oxidative, neuroprotective and anti-cancer activities.

CONCLUSIONS

Modern pharmacological studies have demonstrated that Leonurus japonicus has marked bioactivities, especially on the uterus and as a cardioprotective agent. These activities are related to its traditional use and provide prospects for the development of novel drugs, therapeutics and health care products for women. However, the toxicity of Leonurus japonicus will require further study, and the nomenclature for Leonurus japonicus will require additional clarification.

A bicyclic diterpenoid with a new 15,16-dinorlabdane carbon skeleton from Leonurus japonicus and its coagulant bioactivity

A new 15,16-dinorlabdane diterpenoid 1 and a known labdane diterpenoid 2, together with three known ergosterols 3–5, were isolated from the EtOAc-soluble portion of the EtOH extract of Leonurus japonicus. Their structures were elucidated by physical and spectroscopic analysis. Compound 1 showed in vitro coagulant activity in the APTT, PT, TT, and FIB assays.