Xanthones from Securidaca inappendiculata antagonized the antirheumatic effects of methotrexate in vivo by promoting its secretion into urine

Inhibition mechanism investigation of quercetagetin as a potential tyrosinase inhibitor

Tyrosinase is one important rate limiting enzyme in melanin synthesis, directly affecting the melanin synthesis. Quercetagetin is one active ingredient from marigold. Thence, the inhibition effects of quercetagetin against tyrosinase were investigated. The results showed quercetagetin could inhibit tyrosinase activity with IC50 value of 0.19 ± 0.01 mM and the inhibition type was a reversible mixed-type. Results of fluorescence quenching showed quercetagetin could quench tyrosinase fluorescence in static process. CD and 3D fluorescence results showed the interaction of quercetagetin to tyrosinase could change tyrosinase conformation to inhibit activity. Moreover, docking revealed details of quercetagetin's interactions with tyrosinase.

Securidaca inappendiculata stem extract confers robust antioxidant and antidiabetic effects against high fructose/streptozotocin induced type 2 diabetes in rats. Exploration of bioactive compounds using UHPLC-ESI-QTOF-MS

Diabetes mellitus is the most deadly and most prevalent metabolic disease of contemporary times. This study evaluated the antidiabetic, antioxidant, and pancreato-protective effects of Securidaca inappendiculata extract (SIE) in high-fructose/streptozotocin-induced type 2 diabetes. SIE (50, 100, and 200 mg/kg) was administered to diabetic rats for 8 weeks, thereafter glycaemic parameters, pancreatic β cell function, lipid profile, hepatorenal function, and antioxidant parameters were evaluated in diabetic rats treated SIE. The results indicated that treatment with SIE markedly lowered blood glucose, lipid parameters, hepatorenal function parameters, and lipid peroxidation at the end of the intervention. Additionally, serum insulin levels were significantly increased as supported by restoration of pancreatic β-cell cells in the H&E staining. Moreover, SIE also upregulated serum antioxidant enzyme activities in the treated diabetic rats. The results revealed that SIE possesses potent antihyperglycemic and antihyperlipidemic and antioxidant effects with the considerable restoration of pancreatic β-cells function.

Xanthones from securidaca inappendiculata antagonizes the anti-rheumatic effect of methotrexate by inhibiting reduced folate carrier 1

BACKGROUND

The first-line anti-rheumatic drug methotrexate (MTX) is used in the combination. Because of the unpredictable adverse reactions, optimization of relevant regimens is necessary and meaningful. This study aimed to study the possible interaction between Securidaca inappendiculate Hassk. Derived xanthones and MTX.

METHODS

We established adjuvant-induced arthritis (AIA) model, which was treated with MTX and MTX + xanthone-rich fraction (XRF). The clinical efficacy was evaluated by histopathological examination, and LC-MS was used to monitor the blood concentration of MTX. Western blotting and immunohistochemistry were used to detect protein expression. In vitro, we assessed the activity of related transporters by cellular uptake assay based on HEK-293T cells.

RESULTS

Compared with MTX-treated rats, inflammation in the immunized rats in the MTX + XRF group was obvious, indicating that XRF antagonized the anti-rheumatic effect of MTX. Meanwhile, XRF reduced liver and kidney injuries caused by MTX in addition to MTX. Results from immunohistochemical and nappendiculat assays suggested that XRF may reduce uptake of MTX by down-regulating reduced folate carrier 1 (RFC1).

CONCLUSION

This study indicated that XRF could reduce the plasma concentration of MTX by inhibiting the expression of RFC1, antagonize the therapeutic effect of MTX on AIA rats, and reduce its oral bioavailability. The combination of S. inappendiculate and MTX should be further optimized to achieve the goal of increasing efficiency and reducing toxicity.

Advances in Pharmacokinetic Mechanisms of Transporter-Mediated Herb-Drug Interactions

As the use of herbs has become more popular worldwide, there are increasing reports of herb-drug interactions (HDIs) following the combination of herbs and drugs. The active components of herbs are complex and have a variety of pharmacological activities, which inevitably affect changes in the pharmacokinetics of chemical drugs in vivo. The absorption, distribution, metabolism, and excretion of drugs in vivo are closely related to the expression of drug transporters. When the active components of herbs inhibit or induce the expression of transporters, this can cause changes in substrate pharmacokinetics, resulting in changes in the efficacy and toxicity of drugs. In this article, the tissue distribution and physiological functions of drug transporters are summarized through literature retrieval, and the effects of herbs on drug transporters and the possible mechanism of HDIs are analyzed and discussed in order to provide ideas and a reference for further guiding of safe clinical drug use.

Glycolysis aggravates methotrexate toxicity by fueling RFC1-controlled intestinal absorption in rheumatic rats

Methotrexate (MTX) is a first line anti-rheumatic drug. This study was designed to investigate the impact of rheumatoid arthritis (RA) conditions on its oral absorption, and clarify the relevance with changes of MTX absorption-related transporters in rheumatic models. MTX was orally administered to healthy, collagen-induced arthritis (CIA), and adjuvant-induced arthritis (AIA) rats. MTX plasma concentrations were determined by a validated liquid chromatography-mass spectrometry method. We found that intestinal MTX absorption was significantly increased in CIA/AIA rats versus healthy controls. This finding was supported by small intestine-based MTX uptake assay in vitro. Meanwhile, intestinal expression of both reduced folate carrier 1 (RCF1) and proton-coupled folate transporter (PCFT) remained unchanged. The everted intestinal sac assay confirms RFC1 is the key transporter accounting for intestinal MTX absorption, as its antagonist salicylazosulfapyridine showed potent capacity in reducing MTX uptake. No correlation between RA-related cytokines and RCF1 expression was observed in clinical samples. We further revealed that when cultured with AIA rat or RA patient serum, lactate and adenosine triphosphate (ATP) production as well as MTX uptake in MDCKII cells were significantly increased, and this increase was completely abrogated by ATP production-related metabolic inhibitors. Thanks to its inhibitory effects on MTX bioavailability, the glycolysis inhibitor shikonin diminished MTX-induced injuries of kidney and liver in AIA rats. These data demonstrate that glycolysis-driven high energy metabolism increases MTX absorption in rheumatic subjects, leading to the exacerbated toxicity. These findings will have important implications in optimizing MTX regimens for RA treatment with better efficacy and lower toxicity.

Caffeic acid dimethyl ether alleviates alcohol-induced hepatic steatosis via microRNA-378b-mediated CaMKK2-AMPK pathway

Alcoholic liver disease (ALD), with its increasing morbidity and mortality, has seriously and extensively affected the health of people worldwide. Caffeic Acid Dimethyl Ether (CADE) significantly inhibits alcohol-induced hepatic steatosis in vivo through AMP-activated protein kinase (AMPK) pathway, but its in-depth mechanism remains unclear. This work aimed to clarify further mechanism of CADE in improving hepatic lipid accumulation in ALD through the microRNA-378b (miR-378b)-mediated Ca2+/calmodulin-dependent protein kinase kinase 2 (CaMKK2)-AMPK signaling pathway. Here, we reported that the hepatic or serum triglyceride (TG), total cholesterol (TC), alanine aminotransferase (ALT), and aspartate transaminase (AST) levels were sharply escalated by ethanol while prominently decreased by CADE. Ethanol sharply up-regulated miR-378b expression while CADE effectively prevented the elevation of miR-378b in vivo. And treatment of CADE surely increased mRNA and protein expression of CaMKK2 as a kinase of AMPK and reduced lipid accumulation in the livers of alcohol-fed C57BL/6 mice. MiR-378b escalation exacerbated hepatic steatosis and inhibited CaMKK2-AMPK signaling, while miR-378b deficiency alleviated lipid accumulation and activated the CaMKK2 cascade. Furthermore, CADE alleviated the lipid deposition and reversed the disorder of CaMKK2-AMPK signaling pathway induced by miR-378b over-expression. However, knockdown of miR-378b eliminated the beneficial effect of CADE on lipid metabolism. In brief, our results showed that CADE ultimately improved hepatic lipid deposition by regulating the CaMKK2-AMPK signaling pathway through miR-378b.

Securidaca inappendiculata Polyphenol Rich Extract Counteracts Cognitive Deficits, Neuropathy, Neuroinflammation and Oxidative Stress in Diabetic Encephalopathic Rats via p38 MAPK/Nrf2/HO-1 Pathways

Diabetic encephalopathy is one of the serious emerging complication of diabetes. Securidaca inappendiculata is an important medicinal plant with excellent antioxidant and anti-inflammatory properties. This study investigated the neuroprotective effects of S. inappendiculata polyphenol rich extract (SiPE) against diabetic encephalopathy in rats and elucidated the potential mechanisms of action. Type 2 diabetes mellitus (T2DM) was induced using high fructose solution/intraperitoneal injection of streptozotocin and the diabetic rats were treated with SiPE (50, 100 and 200 mg/kg) for 8 weeks. Learning and memory functions were assessed using the Morris water and Y maze tests, depressive behaviour was evaluated using forced swimming and open field tests, while neuropathic pain assessment was assessed using hot plate, tail immersion and formalin tests. After the experiments, acetylcholinesterase (AChE), oxidative stress biomarkers and proinflammatory cytokines, caspase-3 and nuclear factor kappa-light-chain-enhancer of activated B (NF-κB) were determined by ELISA kits. In addition, the expression levels of p38, phospho-p38 (p-p38), nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were determined by western blot analyses. The results indicated that SiPE administration significantly lowered blood glucose level, attenuated body weight loss, thermal/chemical hyperalgesia, improved behavioural deficit in the Morris water maze, Y maze test and reduced depressive-like behaviours. Furthermore, SiPE reduced AChE, caspase-3, NF-κB, malonaldehyde malondialdehyde levels and simultaneously increased antioxidant enzymes activity in the brain tissues of diabetic rats. SiPE administration also significantly suppressed p38 MAPK pathway and upregulated the Nrf2 pathway. The findings suggested that SiPE exerted antidiabetic encephalopathy effects via modulation of oxidative stress and inflammation.

A new benzophenone, and the antiplasmodial activities of the constituents of Securidaca longipedunculata fresen (Polygalaceae)

Extracts from Securidaca longipedunculata showed antiplasmodial activities against reference clones and clinical isolates using SYBR Green I method. A new benzophenone, 2,3,4,5-tetramethoxybenzophenone (1) was isolated and characterized along with seven known compounds: 4-hydroxy-2,3-dimethoxybenzophenone (2); 3-hydroxy-5-methoxybiphenyl (3), methyl-2-hydroxy-6-methoxybenzoate (4), benzyl-2-hydroxy-6-methoxybenzoate (5), 2-hydroxy-6-methoxybenzoic acid (6), 2,4,5-trimethoxybenzophenone (7) and 2-methoxy-3,4-methylenedioxybenzophenone (8). Compounds 1 and 2 showed ex vivo antiplasmodial activities (IC₅₀ 28.8 μM and 18.6 μM, respectively); while 5 and 8 showed in vivo activities (IC₅₀ 19.7 μM and 14.5 μM, respectively) against D6 strain. In a cytotoxicity assay, all the extracts (with an exception of the MeOH extract of the leaves) and pure compounds were not toxic to the normal LO2 and BEAS cell-lines, while the methanol roots extract (IC₅₀ 66.4 µg/mL against A549, and 77.4 µg/mL against HepG2), compounds 6 (IC₅₀ 22.2 µM against A549) and 7 (IC₅₀ 45.2 µM against HepG2) were weakly active against cancerous cell-lines.

Securidaca inappendiculata-Derived Xanthones Protected Joints from Degradation in Male Rats with Collagen-Induced Arthritis by Regulating PPAR-γ Signaling

Background

The bark of Securidaca inappendiculata Hassk. is traditionally used for treating inflammatory diseases and bone fractures in China. We have previously validated the xanthone-enriched fraction (XRF) of S. inappendiculata with anti-rheumatic potentials, but mechanism underlying the joints protective effects is still largely unknown.

Materials and Methods

The male rats with collagen-induced arthritis (CIA) were treated with XRF. The therapeutic efficacy of XRF was evaluated by arthritis score changes, morphological observation of paws, histological examinations and serological analyses. Protein expression in tissues and cells was investigated by either immunohistochemical or immunoblotting methods, while levels of mRNA expression were investigated by RT-qPCR. Metabolites in serum were detected by LC-MS approach. The joints homogenates were used for analyzing possible targeted genes by genome microarray analyses.

Results

Treatment with XRF and methotrexate (MTX) led to significant decrease in arthritis scores, and alleviated deformation of paws in CIA rats. In addition, XRF and MTX reduced circulating TNF-α, IL-1β and IL-17α in the serum and down-regulated TLR4/NF-κB and JNK pathways in joints of CIA rats. Compared to MTX, XRF-loading microemulsion significantly protected joints, which was accompanied by dramatic decrease in MMP3. Differential genes-based KEGG enrichment and metabolomics analysis suggested that XRF reduced fatty acids biosynthesis by regulating PPAR-γ signaling. S inappendiculata-derived 1,7-dihydroxy-3,4-dimethoxyxanthone (XAN) up-regulated PPAR-γ expression in macrophages, but suppressed it in pre-adipocytes in vitro, which was synchronized with SIRT1 changes. Adiponectin production and SCD-1 expression in pre-adipocytes were also decreased. Aside the direct inhibition on MMP3 expression in synovioblast, the presence of XAN in macrophages-pre-adipocytes co-culture system further reinforced this effect.

Conclusion

This study revealed the joint protective  advantages of the bioactive fraction from S. inappendiculata in CIA rats over MTX, and demonstrated that S. inappendiculata-derived xanthones suppressed the erosive nature of synovioblast acquired under inflammatory circumstances by regulating PPAR-γ signaling-controlled metabolism-immunity feedback.