Loureirin A is a narrow-spectrum antimicrobial agent against Helicobacter pylori.

Currently, Helicobacter pylori eradication by antibiotic therapy faces various challenges, including antibiotic resistance, side effects on intestinal commensal bacteria, and patient compliance. In this study, loureirin A (LrA), a traditional Chinese medicine monomer extracted from Sanguis Draconis flavones, was found to possess specific antibacterial activity against H. pylori without the bacteria displaying a tendency to develop resistance in vitro. LrA demonstrated a synergistic or additive effect when combined with omeprazole (a proton pump inhibitor) against H. pylori. The combination of LrA and omeprazole showed promising anti-H. pylori potential, exhibiting notable in vivo efficacy comparable to standard triple therapy in mouse models infected with both drug-sensitive and drug-resistant H. pylori strains. Moreover, the narrow-spectrum antibacterial profile of LrA is reflected in its minimal effect on the diversity and composition of the mouse gut microbiota. The underlying mechanism of action of LrA against H. pylori involves the generation of bactericidal levels of reactive oxygen species, resulting in apoptosis-like cell death. These findings indicate that LrA is a promising lead compound targeting H. pylori without harming the commensal bacteria.

Loureirin A Promotes Cell Differentiation and Suppresses Migration and Invasion of Melanoma Cells via WNT and AKT/mTOR Signaling Pathways.

Resina Draconis is a traditional Chinese medicine, with the in-depth research, its medicinal value in anti-tumor has been revealed. Loureirin A is extracted from Resina Draconis, however, research on the anti-tumor efficacy of Loureirin A is rare. Herein, we investigated the function of Loureirin A in melanoma. Our research demonstrated that Loureirin A inhibited the proliferation of and caused G0/G1 cell cycle arrest in melanoma cells in a concentration-dependent manner. Further study showed that the melanin content and tyrosinase activity was enhanced after Loureirin A treatment, demonstrated that Loureirin A promoted melanoma cell differentiation, which was accompanied with the reduce of WNT signaling pathway. Meanwhile, we found that Loureirin A suppressed the migration and invasion of melanoma cells through the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway. Taken together, this study demonstrated for the first time the anti-tumor effects of Loureirin A in melanoma cells, which provided a novel therapeutic strategy against melanoma.

[Research on in vivo metabolites of Longxue Tongluo Capsules by liquid chromatography coupled with hybrid ion trap/time-of-flight mass spectrometry].

Longxue Tongluo Capsules(LTC) has good efficacy against blood stasis syndrome during the recovery period of ischemic stroke. Its main active ingredient is the phenolic extract of Chinese dragon's blood. In our previous study, the primary mass fragmentation pathways of phenolic derivatives from LTC were clarified. Herein, the metabolites in rat plasma were characterized following the oral administration of loureirin A and loureirin C using liquid chromatography coupled with hybrid ion trap/time-of-flight mass spectro-metry(LC-IT-TOF-MS), with 18 and 55 metabolites identified, respectively. On this basis, with the help of the obtained accurate molecular weight, characteristic fragment ions, reference comparison, combined with LTC database and natural products database self-created in our group, 18 prototypes and 106 metabolites were tentatively identified in rat plasma after oral gavage of LTC at a dose of 500 mg·kg~(-1). Glucuronidation, sulfonation, and methylation were major biotransformation pathways of LTC. This study preliminarily clarified the LTC constituents absorbed into blood and laid the foundation for clarifying the effective substances of LTC.

Rapid identification of dragon blood samples from Daemonorops draco, Dracaena cinnabari and Dracaena cochinchinensis by MALDI-TOF mass spectrometry.

INTRODUCTION: Dragon blood is a deep-red plant resin which has been used as folk medicine for more than a thousand years. It can be produced from at least four entirely different plant families: Asparagaceae, Arecaceae, Chamaesyce, and Fabaceae. Current pharmacopeia states that the only "authentic" source of dragon blood is the palm tree, Daemonorops draco. OBJECTIVE: The present study aims to find a high-throughput method to screen and identify the plant sources of commercial dragon blood products. METHODOLOGY: A matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) based method for rapid screening of dracorhodin in commercial dragon blood samples was established in this study. RESULTS: Well-resolved peaks of dracorhodin in spectra were observed in the crude extracts of samples. Dragon blood samples from two other plant species, Dracaena cinnabari and Dracaena cochinchinensis, were also examined. Their indicator compounds, loureirin A and B, were detected in these plants. CONCLUSION: A MALDI-TOF based method for preliminarily examination of commercial dragon blood samples is reported here. In contrast to MALDI-TOF, liquid chromatography mass spectrometry (LC-MS) is a time-consuming and costly method, not ideal for routine and large-scale screening of commercial samples.

miR-203a-3p promotes loureirin A-induced hair follicle stem cells differentiation by targeting Smad1.

MicroRNAs (miRNAs) participate in the repair of skin trauma. Our previous study indicated that loureirin A promoted hair follicle stem cells (HFSCs) to repair skin epidermis. However, the mechanism of miRNA-mediated regulation of loureirin A-induced HFSC differentiation remained to be explored. In the present study, HFSCs from rat vibrissa were identified by immunofluorescence in vitro. Microarray and quantitative real time polymerase chain reaction analyses demonstrated that miR-203a-3p was upregulated in differentiated HFSCs induced by loureirin A. The expression of cytoskeletal keratin (CK) 5 and involucrin was promoted by miR-203a-3p mimics while repressed by a miR-203a-3p inhibitor. Smad1 was identified as a key target of miR-203a-3p using target prediction tools. Luciferase reporter gene test confirmed a special target association between miR-203a-3p and Smad1. Short interfering Smad1 was transfected into HFSCs, and the expression levels of CK5 and involucrin were upregulated. Thus, it can be inferred that miR-203a-3p negatively regulated the expression of Smad1 and promoted the differentiation of loureirin A-induced HFSCs. Bone morphogenetic protein (BMP) signal inhibition and Wnt activation coregulate skin injury repair. BMP/Smad1 signaling is involved in maintaining the characteristics of HFSCs and inhibiting their differentiation. Our results showed that miR-203a-3p reduces Smad1 to release BMP inhibition. Taken together, miR-203a-3p/Smad1 is a potential therapeutic molecular target in skin wound healing, and may play an active role in wound repair and regenerative medicine.

Downregulating Akt/NF-κB signaling and its antioxidant activity with Loureirin A for alleviating the progression of osteoarthritis: In vitro and vivo studies.

Osteoarthritis(OA) is one of the most common diseases in orthopedics. It is characterized by degeneration of articular cartilage and chronic inflammation. In this study, we aim to elucidate the mechanism of Loureirin A's therapeutic effect in OA progression. In vitro, Loureirin A pretreatment can significantly inhibit production of NO, PGE2, COX-2, TNF-α, iNOS andIL-6 induced by IL-1ß in mouse articular chondrocytes. Moreover, Loureirin A suppressed the expression of matrix metalloproteinase-9(MMP-9), which leads to degradation of the extracellular matrix. The degradation of aggrecan and type II collagen protein in the extracellular matrix (ECM) stimulated by IL-1ß was reversed. For signal pathway research, Loureirin A dramatically inhibited the phosphorylation of AKT and subsequent NF-κB entering into the nucleus caused by IL-1ß in chondrocytes. Besides, a number of related indicators suggested that Loureirin A has a strong antioxidant activity in the treatment of osteoarthritis via increasing content of SOD2 and suppressing MDA and ROS. In addition, in vivo study demonstrated that Loureirin A could ameliorated the progression of OA in mice DMM model In conclusion, all results showed that Loureirin A may be a potential therapeutic candidate for the OA.

Effect of loureirin A against Candida albicans biofilms.

Loureirin A is a major active component of Draconis sanguis, a traditional Chinese medicine. This work aimed to investigate the activity of loureirin A against Candida albicans biofilms. 2, 3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT)reduction assay and scanning electron microscopy were used to investigate the anti-biofilm effect. Minimal inhibitory concentration testing and time-kill curve assay were used to evaluate fungicidal activity. Cell surface hydrophobicity (CSH) assay and hyphal formation experiment were respectively carried out to investigate adhesion and morphological transition, two virulence traits of C. albicans. Real-time RT-PCR was used to investigate gene expression. Galleria mellonella-C. albicans and Caenorhabditis elegans-C. albicans infection models were used to evaluate the in-vivo antifungal effect. Human umbilical vein endothelial cells and C. elegans nematodes were used to evaluate the toxicity ofloureirin A. Our data indicated that loureirin A had a significant effect on inhibiting C. albicans biofilms, decreasing CSH, and suppressing hyphal formation. Consistently, loureirin A down-regulated the expression of some adhesion-related genes and hypha/biofilm-related genes. Moreover, loureirin A prolonged the survival of Galleria mellonella and Caenorhabditis elegans in C. albicans infection models and exhibited low toxicity. Collectively, loureirin A inhibits fungal biofilms, and this effect may be associated with the suppression of pathogenic traits, adhesion and hyphal formation.

Antiplatelet activity of loureirin A by attenuating Akt phosphorylation: In vitro studies.

Loureirin A is a flavonoid extracted from Dragon׳s Blood that has been used to promote blood circulation and remove stasis in Chinese traditional medicine. However, the mechanisms of these effects are not fully understood. We explored the anti-platelet activity and underlying mechanism of loureirin A in vitro. Our results indicated that loureirin A negatively affected agonist-induced platelet aggregation such as collagen, collagen-related peptide (CRP), ADP and thrombin. Loureirin A inhibited collagen-induced platelet ATP secretion and thrombin-stimulated P-selectin expression in a dose-dependent manner. Platelet spreading on immobilized fibrinogen was significantly impaired in the presence of loureirin A. Immunoblotting analysis indicated that 100µM of loureirin A almost completely eliminated collagen-induced Akt phosphorylation at Ser473. Interestingly, a submaximal dose (50µM) of loureirin A had an additive inhibitory effect with the phosphoinositide 3-kinase (PI3K) inhibitor Ly294002 on collage-induced Akt phosphorylation in platelets. Taken together, loureirin A had an inhibitory effect on platelet activation, perhaps through an impairment of PI3K/Akt signaling.

Comparison between loureirin A and cochinchinenin C on the interaction with human serum albumin.

The interactions of loureirin A (LA) and cochinchinenin C (CC) with human serum albumin (HSA) under simulated physiological conditions (pH = 7.4) have been studied with fluorescence, UV-vis absorption spectroscopic method and molecular docking technique. The results indicated that there was a synergistic interaction between LA and CC, and the fluorescence quenching of HSA by LA (or CC) was a combined quenching procedure (dynamic and static quenching). At low compound concentrations, the quenching constants KSV of CC was larger than that of LA, which meant the CC efficacy may be better than that of LA. The negative △H and △S values suggested hydrogen bonds and van der Waals forces played the major role in the binding of LA (or CC) to HSA. The efficiency of energy transfer and distance between the compounds and HSA was calculated. Moreover, the results of synchronous and three-dimensional fluorescence demonstrated that the HSA microenvironment was changed in the presence of LA (or CC). Finally, the binding of LA (or CC) to HSA was modeled by molecular docking, which is in good accordance with the experimental studies.

Dihydrochalcones and homoisoflavanes from the red resin of Dracaena cochinchinensis (Chinese dragon's blood).

Two new dihydrochalcones, 4-hydroxy-2,4'-dimethoxydihydrochalcone (1) and 3,4'-dihydroxy-2,4,6-trimethoxydihydrochalcone (2), and a new homoisoflavane, 7,3'-dihydroxy-8,4'-dimethoxyhomoisoflavane (3), along with 12 known compounds (4-15), were isolated from the red resin of Dracaena cochinchinensis (Chinese dragon's blood). Their structures were assigned by a variety of spectroscopic techniques. Diversity of cleavage pathways were proposed for dihydrochalcones and homoisoflavanes based on the mass spectroscopic behaviors of those identified compounds using hybrid ion trap-time of flight mass spectrometry. All the compounds were evaluated for their inhibitory effects on nitric oxide production in lipopolysaccharide-induced RAW 264.7 macrophages, and compound 9 exhibited mild inhibition of NO production in this assay with IC50 value of 50.3 µM.

Beneficial effects of the Chinese herbal medicine Sanjie Zhentong Capsule on experimental endometriosis in rats.

AIM: To analyze the composition of the Chinese herbal medicine Sanjie Zhentong Capsule (SJZTC) and test the therapeutic efficacy of each component in a rat model of endometriosis. METHODS: A rapid resolution liquid chromatography (RRLC) method coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS) has been developed for the analysis of SJZTC. Two main ingredients, Drac(h)onis sanguis and saponin, were tested in the endometriosis model. Sixty Lewis female rats were in the estrous cycle stage when endometriosis was experimentally initiated by peritoneal implantation of endometrial tissue. Four weeks later, a second laparotomy was performed and implant volumes were measured. After that, the implanted rats were randomized into five study groups: control group (treatment with saline), anastrozole group (treatment with anastrole, 18 µg per day), loureirin A group (treated with loureirin A, 97.2 mg), ginsenoside Re group (treated with ginsenoside Re, 64.8 mg), and SJZTC groups (treated with SJZTC, 86.4 mg) administered once a day for 4 weeks via gastric gavage. After four weeks of treatment, a third laparotomy was performed, implant volumes were re-measured, and the levels of vascular endothelial growth factor (VEGF) and tumor necrosis factor-alpha (TNF-α) were tested. RESULTS: A total of 38 compounds including, both the target and unknown compounds, were rapidly predicted in the capsule extract by the developed method. Compared with the control group, the anastrozole group, loureirin A group, ginsenoside Re group, and SJZTC treated group showed smaller implant volumes, as well as lower levels of VEGF and TNF-α in the peritoneal focus (P < 0.01 for all comparisons). Furthermore, parameters in the groups treated with SJZTC, loureirin A and ginsenoside Re were significantly better than the control group and the anastrozole group. These results indicate that SJZTC and its two main components are effective in reducing the development of endometriosis.