The chloroform fraction of Solanum nigrum suppresses nitric oxide and tumor necrosis factor-α in LPS-stimulated mouse peritoneal macrophages through inhibition of p38, JNK and ERK1/2

Solanum nigrum L., commonly known as black nightshade, is used worldwide for the treatment of skin and mucosal ulcers, liver cirrhosis and edema. We aimed to determine the anti-inflammatory active fraction of S. nigrum by serial extractions. S. nigrum was first extracted with methanol, then fractionated with chloroform and water. The effects of S. nigrum fractions, diosgenin and α-solanine on LPS/interferon-gamma-induced nitric oxide (NO) and inducible NO synthase (iNOS), or LPS-induced tumor necrosis factor-α (TNF-α) and interleukin (IL)-6, in mouse peritoneal macrophages were determined. Western blotting analysis was used to detect LPS-induced phosphorylation of p38, JNK and ERK1/2. The chloroform fraction of S. nigrum was cytotoxic in a time and concentration dependent manner; however, the methanol and water fractions were not. The chloroform fraction reduced NO through inhibition of iNOS synthesis and inhibited TNF-α and IL-6 at the level of protein secretion; the methanol and water fractions showed a weak or no effect. The chloroform fraction also suppressed p38, JNK and ERK1/2. Diosgenin and α-solanine were cytotoxic at a high concentration. In particular, diosgenin was able to inhibit TNF-α and IL-6, but both compounds did not affect LPS-induced iNOS expression. These results indicate that the anti-inflammatory compounds of S. nigrum exist preferentially in the nonpolar fraction, ruling out the possibility that diosgenin and α-solanine are the likely candidates. The inhibition of iNOS, TNF-α and IL-6 by the chloroform fraction may be partly due to the suppression of p38, JNK and ERK1/2. Further study is required to identify the active compounds of S. nigrum.     

Flower extract of Panax notoginseng attenuates lipopolysaccharide-induced inflammatory response via blocking of NF-κB signaling pathway in murine macrophages

Aim of the study

The root of Panax notoginseng (PN) is commonly used to treat chronic liver disease with its therapeutic abilities to stop haemorrhage in the circulation, while the PN flower (PN-F) is largely unknown in the biological activities on inflammation and mechanisms of its actions. In this study, the pharmacologic effects of PN-F methanol extract on inflammation were investigated to address potential therapeutic or toxic effects in LPS-stimulated mouse macrophage cells, RAW264.7 cells.

Materials and methods

Production of NO, PGE₂ and pro-inflammatory cytokines (TNF-α and IL-1β) in supernatant, the expression of iNOS, COX-2 and cytokines, the phosphorylation of MAPK moleduces (ERK1/2, JNK and p38 MAPK), and the activation of NF-κB in PN-F extract were assayed in LPS-stimulated RAW264.7 cells.

Results

PN-F extract significantly inhibited the productions of NO, PGE₂, TNF-α and IL-1β on the LPS-stimulated RAW264.7 cells. In addition, PN-F extract suppressed the mRNA and protein expressions of iNOS, COX-2, TNF-α and IL-1β in LPS-stimulated RAW264.7 cells. The molecular mechanism of PN-F extract-mediated attenuation in RAW264.7 cells has close a relationship to suppressing the phosphorylation of MAPK molecules such as ERK1/2, JNK and p38 MAPK, and the translocation of NF-κB p65 subunit into nuclear.

Conclusion

These results indicate that PN-F extract inhibits LPS-induced inflammatory response via the blocking of NF-κB signaling pathway in macrophages, and demonstrated that PN-F extract possesses anti-inflammatory properties in vitro.     

Anti-inflammatory and anti-nociceptive effect of Betula platyphylla var. japonica in human interleukin-1β-stimulated fibroblast-like synoviocytes and in experimental animal models

Ethnopharmacological relevance

Traditional medicine has widely been used Betula platyphylla var. japonica to treat various inflammatory diseases including arthritis.

Aim of the study

To determine the anti-inflammatory, anti-nociceptive, and anti-arthritic effects of Betula platyphylla in interleukin-1β (IL-1β)-stimulated fibroblast-like synoviocytes from human rheumatoid arthritis and in nociceptive and inflammatory animal model.

Materials and methods

The inflammatory mediators such as IL-6, tumor necrosis factor (TNF)-α matrix metalloproteinase (MMP)-1, MMP-13, inducible nitric oxide synthesis (iNOS), nitrites, prostaglandin E₂ (PGE₂) and cyclo-oxygenase 2 (COX-2) activity of Betula platyphylla were tested in IL-1β-stimulated fibroblast-like synoviocytes. Tail withdrawal in response to thermal stimulation in tail flick test or paw flinching and shaking in response to sc hind paw formalin injection was measured 1 h after oral administration of Betula platyphylla. The former was evaluated with a paw pressure test, and the latter was measured using the squeaking score, and paw volume in inflammatory arthritis tests.

Results

Betula platyphylla significantly inhibited proliferation of IL-1β-induced synoviocytes. Betula platyphylla reduced the levels of inflammatory mediators, such as IL-6, TNF-α, MMP-1, MMP13, and PGE₂. In particular, Betula platyphylla significantly inhibited the releases of nitrites and iNOS, as well as release of NFκB, into the nucleus of IL-1β-treated synoviocytes, even at concentrations as low as 1 μg/ml. Oral administrant of Betula platyphylla at 400 mg/kg significantly decreased about 27.8% of tail flick withdrawal and inhibited about the number of paw flinches in both phases 1 and 2 of the formalin test. In the carrageenan-induced acute pain and arthritis model, Betula platyphylla dose dependently reduced the nociceptive threshold and the arthritic symptoms at day 8, respectively, and Betula platyphylla at 400 mg/kg markedly reduced the inflammatory area about 48% in the ankle joints. This capacity of Betula platyphylla at 400 mg/kg was similar to that of the celecoxib-2 inhibitor in carrageenan-induced nociceptive and inflammatory arthritis model.

Conclusions

These results suggest that Betula platyphylla has anti-nociceptive and anti-inflammatory effects in IL-1β-stimulated RA FLS and in an animal model of arthritis. Thus, the use of Betula platyphylla as a pharmaceutical candidate for the treatment of arthritis should be further studied.     

The effect of the extract of Crocus sativus on tracheal responsiveness and plasma levels of IL-4, IFN-γ, total NO and nitrite in ovalbumin sensitized Guinea-pigs

Ethnomedical relevance

Anti-inflammatory, anti oxidant and effect of Crocus sativus (C. sativus) on Th₁/Th₂ balance were described previously.

Aim of the study

The preventive effects of the extract of Crocus sativus on tracheal responsiveness and plasma levels of IL-4, IFN-γ, total NO and nitrite were examined on sensitized guinea pigs.

Materials and methods

Five groups of sensitized guinea pigs to ovalbumin (OVA), were given drinking water containing three concentrations of the extract of Crocus sativus, dexamethasone (S+D) or alone (group S). Tracheal responses (TR) of control animals (group C) and sensitized guinea pigs (n=6, for each group) to methacholine, OVA and the levels of IL-4, IFN-γ, total NO and nitrite in serum were examined.

Results

The TR to both methacholine and OVA, the levels of serum IL-4, total NO and nitrite in S guinea pigs were significantly increased but that of IFN-γ and IFN-γ/IL-4 ratio (Th₁/Th₂ balance) were decreased compared to the controls (p<0.05 to p<0.001). In the treated animals with dexamethasone and all concentrations of the extract, TR to both methacholine and OVA, IL-4, total NO and nitrite were significantly decreased but IFN-γ and IFN-γ/IL-4 ratio increased compared to S group (p<0.05 to p<0.001). The effects of the highest concentration of the extract was greater than those of other concentrations and the effect of dexamethasone (p<0.05 to p<0.01).

Conclusions

These results not only showed a preventive effect of C. sativus extract on tracheal responses and serum levels of inflammatory mediators in sensitized guinea pigs but also showed increased Th₁/Th₂ balance.     

Chrysanthemum indicum Linné extract inhibits the inflammatory response by suppressing NF-κB and MAPKs activation in lipopolysaccharide-induced RAW 264.7 macrophages

Aims of study

Although the flowers of Chrysanthemum indicum Linné (Asteraceae) have long been used in traditional Korean and Chinese medicine to treat inflammatory diseases, the underlying mechanism(s) by which these effects are induced remains to be defined. We investigated the effects of a 70% ethanolic extract of C. indicum (CIE) on the activities of cellular signaling molecules that mediate inflammatory responses.

Materials and methods

Production of NO, PGE₂, TNF-α, and IL-1β by ELISA, mRNA and protein expression of iNOS and COX-2, phosphorylation of MAPKs, and activation of NF-κB by RT-PCR and Western blotting were examined in LPS-induced RAW 264.7 macrophages.

Results

The CIE strongly inhibited NO, PGE₂, TNF-α, and IL-1β production, and also significantly inhibited mRNA and protein expression of iNOS and COX-2 in LPS-induced RAW 264.7 macrophages, in a dose-dependent manner. Furthermore, the CIE clearly suppressed nuclear translocation of NF-κB p65 subunits, which correlated with an inhibitory effect on IκBα phosphorylation. The CIE also attenuated the activation of ERK1/2 and JNK in a dose-dependent manner.

Conclusion

Our results suggest that the anti-inflammatory properties of CIE might result from the inhibition of inflammatory mediators, such as NO, PGE₂, TNF-α, and IL-1β, via suppression of MAPKs and NF-κB-dependent pathways.     

β Mangostin suppress LPS-induced inflammatory response in RAW 264.7 macrophages in vitro and carrageenan-induced peritonitis in vivo

Ethnopharmacological relevance

The fruit hull of Garcinia mangostana Linn. has been used in traditional medicine for treatment of various inflammatory diseases. Hence, this study aims to investigate the in vitro and in vivo anti-inflammatory effect of β mangostin (βM), a major compound present in Garcinia mangostana.

Materials and methods

The in silico analysis of inflammatory mediators such as cyclooxygenase (COX) and nuclear factor-kappa B (NF-kB) were performed via molecular docking. Further evaluation of anti-inflammatory effect was conducted in lipopolysaccharide (LPS) induced RAW 264.7 macrophages. Suppression of activated NF-kB was analyzed by high content screening. βM triggered inhibition of COX-1 and COX-2 in vitro were studied using biochemical kit. The in vivo model used in this study was carrageenan-induced peritonitis model, where reduction in carrageenan-induced peritonitis is measured by leukocyte migration and vascular permeability. In addition, the evaluation of βM?s effect on carrageenan induced TNF-α and IL-1β release on peritoneal fluid was also carried out.

Results

Treatment with βM could inhibit the LPS-induced NO production but not the viability of RAW 264.7. Similarly, βM inhibited PGE₂ production and the cytokines: TNF-α and IL-6. The COX catalyzed prostaglandin biosynthesis assay had showed selective COX-2 inhibition with a 53.0±6.01% inhibition at 20 µg/ml. Apart from this, βM was capable in repressing translocation of NF-kB into the nucleus. These results were concurrent with molecular docking which revealed COX-2 selectivity and NF-kB inhibition. The in vivo analysis showed that after four hours of peritonitis, βM was unable to reduce vascular permeability, yet could decrease the total leukocyte migration; particularly, neutrophils. Meanwhile, dexamethasone 0.5 mg/kg, successfully reduced vascular permeability. The levels of TNF-α and IL-1β in peritoneal fluid was reduced significantly by βM treatment.

Conclusion

The current study supports the traditional use of Garcinia mangostana fruit hull for treatment of inflammatory conditions. In addition, it is clear that the anti-inflammatory efficacy of this plant is not limited to the presence of α and γ, but β also with significant activity.     

Anti-arthritic activity of Xanthium strumarium L. extract on complete Freund׳s adjuvant induced arthritis in rats

Ethnopharmacological relevance

Xanthium strumarium L. fruit (Xanthiu fruit) has been traditionally used as a medicinal herb in China for the treatment of many ailments including rheumatoid arthritis. However, the anti-arthritic activity of Xanthium strumarium fruit has still not been demonstrated. In the present study, we confirmed that the extract of Xanthium strumarium (EXS) prevents rheumatoid arthritis induced by Complete Freund?s Adjuvant (CFA) in rats.

Materials and methods

Male Wistar rats (160±10 g) were immunized by intradermal injection of 0.1 mL of CFA into the left hind metatarsal footpad. EXS was administered orally at a dose of 300 and 75 mg/kg once a day after the induction of adjuvant arthritis. Methotrexate (3 mg/kg, twice a week) was used as a positive control. Paw swelling, arthritic score, body weight loss, spleen index, thymus index, serum cytokines, inflammatory mediators and histological change were measured. The chemical profile of EXS was analyzed by HPLC-DAD.

Results

We found that the EXS significantly suppressed paw swelling and arthritic score, increased body weight loss and decreased the thymus index. The overproduction of TNF-α and IL-1β were remarkably suppressed in the serum of all EXS-treated rats, and in contrast IL-10 was markedly increased. The level of COX-2 and 5-LOX was also decreased with EXS treatment. Ten phenolic acid derivatives were identified from 14 detected peaks by HPLC-DAD with the reference substances and verified by LC–MS.

Conclusions

These results suggest the potential effect of EXS as an anti-arthritis agent towards CFA-induced arthritis in rats. Xanthium strumarium has the potential to be regarded as a candidate for use in general therapeutics and as an immune-modulatory medicine in rheumatoid arthritis.     

Inhibitory effects of Angelica sinensis ethyl acetate extract and major compounds on NF-κB trans-activation activity and LPS-induced inflammation

Aim of the study

Previous study showed that the ethyl acetate (EtOAc) fraction from Angelica sinensis (Oliv.) Diels (Apiaceae) (AS) inhibited nitric oxide (NO) and prostaglandin E₂ secretions in vitro. This study was to evaluate anti-inflammatory activity of AS EtOAc extract and its major compounds in vivo and in vitro.

Materials and methods

NF-κB luciferase activity and pro-inflammatory cytokine secretions from lipopolysaccharide (LPS) plus interferon (IFN)-γ-stimulated RAW 264.7 cells pre-treated with EtOAc extract or compounds were analyzed. For further in vivo study, BALB/c mice were tube-fed with 1.56 (AS1 group), 6.25 (AS2 group) mg/kg body weight/day in 100 μl soybean oil, while the control and PDTC (pyrrolidine dithiocarbamate, an anti-inflammatory agent) groups were tube-fed with 100 μl soybean oil/day only. After 1 week of tube-feeding, the PDTC group was injected with 50 mg/kg BW PDTC and 1 h later, all of the mice were injected with 15 mg/kg BW LPS. The pro-inflammatory cytokine levels and lifespan of LPS-challenged mice were determined.

Results

The results showed that AS EtOAc extract significantly inhibited NF-κB luciferase activity and TNF-α, IL-6, macrophage inflammatory protein-2 (MIP-2) and NO secretions from LPS/IFN-γ-stimulated RAW 264.7 cells. The AS1 and PDTC groups, but not AS2, had significantly higher survival rate than the control group. This was characterized by the inhibition of the serum TNF-α and IL-12p40 levels after LPS injection (p < 0.05). The major compounds of AS, ferulic acid and Z-ligustilide, also significantly decreased NF-κB luciferase activity, which may contribute to the anti-inflammatory activity of AS.

Conclusions

Low dose of AS EtOAc extract that inhibits the production of inflammatory mediators alleviates acute inflammatory hazards and protect mice from endotoxic shock.     

Anti-diabetic effects of Centratherum anthelminticum seeds methanolic fraction on pancreatic cells, β-TC6 and its alleviating role in type 2 diabetic rats

Ethnopharmacological relevance

Seeds of Centratherum anthelminticum (Asteraceae) have been popularly used in Ayurvedic medicine to treat diabetes and skin disorders. Folk medicine from Rayalaseema (Andhra Pradesh, India) reported wide spread usage in diabetes.

Aim of the study

To investigate the hypoglycemic properties and mechanism of the methanolic fraction of C. anthelminticum seeds (CAMFs) on mouse β-TC6 pancreatic cell line and streptozotocin (STZ)-induced diabetic rat models.

Materials and Methods

We investigated the crude methanolic fraction of C. anthelminticum seeds (CAMFs) on β-TC6 cell line and confirmed its effects on type 1 and type 2 diabetic rats to understand its mechanism in managing diabetes mellitus. CAMFs were initially tested on β-TC6 cells for cytotoxicity, 2-NBDG glucose uptake, insulin secretion and glucose transporter (GLUT-1, 2 and 4) protein expression. Furthermore, streptozotocin (STZ)-induced type 1 diabetic and STZ-nicotinamide-induced type 2 diabetic rats were intraperitoneally (i.p) injected or administered orally with CAMFs daily for 28 days. The effect of CAMFs on blood glucose and insulin levels was subsequently evaluated.

Results

In cell line studies, CAMFs showed non-cytotoxic effect on β-TC6 cell proliferation compared to untreated control cells at 50 μg/ml. CAMFs increased glucose uptake and insulin secretion dose-dependently by up-regulating GLUT-2 and GLUT-4 expression in these cells. Further in vivo studies on streptozotocin induced diabetic rat models revealed that CAMFs significantly reduced hyperglycemia by augmenting insulin secretion in type 2 diabetic rats. However, CAMFs displayed less significant effects on type 1 diabetic rats.

Conclusions

CAMFs demonstrated anti-diabetic potential on β-TC6 cells and type 2 diabetic rat model, plausibly through enhancing glucose uptake and insulin secretion.     

The effects of lignan-riched extract of Shisandra chinensis on amyloid-β-induced cognitive impairment and neurotoxicity in the cortex and hippocampus of mouse

Ethnopharmacological relevance

The fruits of Schisandra chinensis (Trucz.) Baill. (Schisandraceae) which have been used as a tonic especially for kidney yin deficiency in Chinese traditional medicine are recently receiving attention for its preventive activity on age-related neurodegenerative diseases. A variety of studies demonstrated the cognitive-enhancing effects of Schisandra chinensis through animal tests and also in clinical trials.

Aim of study

In this study, we attempted to investigate the effects of the lignan-riched extract of Schisandra chinensis fruits (ESP-806) on neurotoxicity and memory impairment induced by Aβ_1–42 injection in mice.

Materials and methods

The fruits of Schisandra chinensis were extracted with the mixture of n-hexane:ethanol (9:1), which is riched with bioactive dibenzocyclooctadiene lignans, schizandrin, gomisin N, wuweigisu C. After oral treatment of ESP-806 (100 mg/kg body weight) followed by injection of Aβ_1–42 (2 μg/mouse, i.c.v.), novel object recognition and passive avoidance tests were evaluated. To verify the cognition enhancing effects of ESP-806, we examined the effects of ESP-806 on the activities of β-secretase and acetylcholinesterase, and the contents of Aβ and the reduced glutathione within the cortex and hippocampus of Aβ-injected mice.

Results

Oral treatment of ESP-806 (100 mg/kg body weight) significantly attenuated Aβ_1–42-induced memory impairment evaluated by behavioral tests. Furthermore, the treatment of ESP-806 attenuated the elevation of β-secretase activity accompanying the reduced level of Aβ_1–42 in the cortex and hippocampus of the brain. ESP-806 also significantly inhibited the acetylcholinesterase activity in the hippocampus and increased the content of the reduced glutathione in the cortex and hippocampus of mouse brain.

Conclusions

These data suggested that the extract of Schisandra chinensis fruits riched with dibenzocyclooctadiene lignans may be useful in the prevention and treatment of Alzheimer's disease.     

Inhibitory effect of St. John׳s Wort oil macerates on TNFα-induced NF-κB activation and their fatty acid composition

Ethnopharmacological relevance

The oil macerates of Hypericum perforatum L. (St. John?s Wort=SJW) have a long history of medicinal use and SJW has been used in traditional medicine both orally and topically for centuries worldwide mainly for wound healing, ulcer and inflammation.

Materials and methods

We analyzed the fatty acid composition of 10 traditionally (home-made) and 13 commercially (ready-made) prepared SJW oil macerates by GC–MS. The acid, peroxide, iodine, saponification values, and the unsaponifiable matters of the samples were determined according to the European Pharmacopoeia. We also explored potential mechanism of wound healing effect of the samples, i.e. TNFα-induced NF-κB activation.

Results

The most home-made oil samples contained oleic acid predominantly and complied with the requirements set for olive oil by European Pharmacopoeia. However, majority of the ready-made samples appeared to have adulteration with some other oils. Moderate NF-κB inhibitory effects have been observed with some of the oil samples.

Conclusion

This study sheds light on the fact that application of the proper traditional method to prepare olive oil macerates from Hypericum perforatum is able to get bioactive constituents in the oil. Besides, inhibition of TNFα-induced NF-κB activation appears to be a potential mechanism for topical wound healing activity of SJW oil macerates.     

The protective effect of smilax glabra extract on advanced glycation end products-induced endothelial dysfunction in HUVECs via RAGE-ERK1/2-NF-κB pathway

Ethnopharmacological relevance

Smilax glabra Roxb. (SGR) is a traditional Chinese herb that has been used in folk for the treatment of diabetic vascular complications. Advanced glycation end products (AGEs)-induced endothelial dysfunction has been thought to be a major cause of diabetic vascular complications. The present study was conducted to investigate the protective effect of SGR extract on AGEs-induced endothelial dysfunction and its underlying mechanisms.

Materials and methods

Human umbilical vein endothelial cells (HUVECs) were exposed to 200 μg/ml AGEs to induce endothelial dysfunction. Acridine orange/ethidium bromide (AO/EB) fluorescence assay and Annexin-V/PI double-staining were performed to determine endothelium apoptosis. Dihydroethidium (DHE) fluorescence probe, SOD and MDA kits were used to evaluate oxidative stress. The effect of SGR extract on AGEs-induced TGF-beta1 expression was determined by immunocytochemistry and western blotting. Attenuations of SGR extract on receptor for AGEs (RAGE) expression, extracellular regulated protein kinases (ERK1/2) activation and NF-κB phosphorylation were determined by immunofluorescence assay and western blotting. The blockade assays for RAGE and ERK1/2 were carried out using a specific RAGE-antibody (RAGE-Ab) or a selective ERK1/2 inhibitor PD98059 in immunofluorescence assay.

Results

The pretreatment of SGR extract (0.125, 0.25 and 0.5 mg crude drug/ml) significantly attenuated AGEs-induced endothelium apoptosis, and down-regulated TGF-beta1 protein expression in HUVECs. It was also well shown that SGR extract could down-regulate dose-dependently ROS over-generation, MDA content, TGF-beta1 expression, ERK1/2 and NF-κB activation whereas increase significantly SOD activity. Furthermore, the AGEs-induced ERK1/2 activation could be attenuated by the blockade of RAGE-Ab (5 μg/ml) while the NF-κB activation was ameliorated by ERK1/2 inhibitor PD98059 (10 μM).

Conclusion

These results indicated that SGR extract could attenuate AGEs-induced endothelial dysfunction via RAGE-ERK1/2-NF-κB pathways. Our findings suggest that SGR extract may be beneficial for attenuating endothelial dysfunction in diabetic vascular complications.     

Effects of curcumin/turmeric supplementation on obesity indices and adipokines in adults: A grade-assessed systematic review and dose–response meta-analysis of randomized controlled trials

In the present study, we explored the effect of curcumin/turmeric supplementation on anthropometric indices of obesity, leptin, and adiponectin. We searched PubMed, Scopus, Web of Science, Cochrane Library, and Google Scholar up to August 2022. Randomized clinical trials (RCTs) investigating the impact of curcumin/turmeric on obesity indices and adipokines were included. We applied the Cochrane quality assessment tool to evaluate the risk of bias. The registration number is CRD42022350946. Sixty eligible RCTs, with a total sample size of 3691 individuals were included for quantitative analysis. We found that supplementation with curcumin/turmeric significantly reduced body weight (WMD: −0.82 kg, 95% CI: −1.30, −0.35; p = 0.001), body mass index (WMD: −0.30 kg/m², 95% CI: −0.53, −0.06, p = 0.013), waist circumference (WMD: −1.31 cm, 95% CI: −1.94, −0.69, p < 0.001), body fat percentage (WMD: −0.88%, 95% CI: −1.51, −0.25, p = 0.007), leptin (WMD = −4.46 ng/mL; 95% CI: −6.70, −2.21, p < 0.001), and increased adiponectin (WMD = 2.48 μg/mL; 95% CI: 1.34, 3.62, p < 0.001). Overall, our study shows that supplementation with curcumin/turmeric significantly improves anthropometric indices of obesity and adiposity-related adipokines (leptin and adiponectin). However, due to high between-studies heterogeneity, we should interpret the results with caution.     

The effect of mitragynine on cAMP formation and mRNA expression of mu-opioid receptors mediated by chronic morphine treatment in SK–N–SH neuroblastoma cell

Ethopharmacological relevance

Mitragynine is an indole alkaloid compound of Mitragyna speciosa (M. speciosa) Korth. (Rubiaceae). This plant is native to the southern regions of Thailand and northern regions of Malaysia and is frequently used to manage the withdrawal symptoms in both countries.

Aim of study

To investigate the effect of mitragynine after chronic morphine treatment on cyclic AMP (cAMP) level and mRNA expression of mu-opioid receptor (MOR) in human neuroblastoma SK–N–SH cell.

Method and Materials

Mitragynine was isolated from the Mitragyna speciosa plant using the acid–base extraction method. The cAMP level upon forskolin stimulation in the cells was determined using the Calbiochem^® Direct Immunoassay Kit. The mRNA expression of the MOR was carried out using quantitative RT-PCR.

Result

Cotreatment and pretreatment of morphine and mitragynine significantly reduced the production of cAMP level at a lower concentration of mitragynine while the higher concentration of this compound could lead to the development of tolerance and dependence as shown by the increase of the cAMP level production in foskolin stimulation. In MOR mRNA expression study, cotreatment of morphine with mitragynine significantly reduced the down-regulation of MOR mRNA expression as compared to morphine treatment only.

Conclusion

These finding suggest that mitragynine could possibly avoid the tolerance and dependence on chronic morphine treatment by reducing the up-regulation of cAMP level as well as reducing the down-regulation of MOR at a lower concentration of mitragynine.     

Inhibitory effect of medicinal plant-derived carboxylic acids on the human transporters hOAT1, hOAT3, hOATP1B1, and hOATP2B1简

A significant number of organic carboxylic acids have been shown to influence the absorption and distribution of drugs mediated by organic anion transporters （OATs）. In this study, uptake experiments were performed to assess the inhibitory effects of cinnamic acid, ferulic acid, oleanolic acid, deoxycholic acid, and cynarin on bOAT1, hOAT3, hOATP 1B l, and hOATP2B 1. After a drug-drug interaction （DDI） investigation, cinnamic acid, ferulic acid, deoxycholic acid, and cynarin were found and validated to inhibit hOAT1 in a competitive manner, and deoxycholic acid was found to be an inhibitor of all four transporters. The apparent 50% inhibitory concentrations of cinnamic acid, ferulic acid, deoxycholic acid, and cynarin were estimated to be 133.87, 3.69, 90.03 and 6.03 μmol·L ^-1 for hOAT1, respectively. The apparent 50% inhibitory concentrations of deoxycholic acid were estimated to be 9.57μmol·L ^-1 for hOAT3, 70.54 μmol·L ^-1 for hOATP1B1, and 168.27μmol·L ^-1 for hOATP2B1. Because cinnamic acid, ferulic acid, and cynarin are ingredients of food or food additives, the present study suggests there are new food-drug interactions to be disclosed. In addition, deoxycholic acid may be used as a probe for studying the correlation of OATs and OATPs.