The antioxidative activity of traditional Japanese herbs

Acteoside from Conandron ramondioides Reduces Microcystin-LR Cytotoxicity by Inhibiting Intracellular Uptake Mediated by OATP1B3

The hepatotoxin microcystin-LR is a strong inhibitor of serine/threonine protein phosphatase (PP) 1 and PP2A. The onset of its cytotoxicity depends on its selective uptake via the hepatocyte uptake transporters, organic anion transporting polypeptide (OATP) 1B1 and OATP1B3. Understanding and preventing the cytotoxicity of microcystin-LR is crucial to maintain human health. This chemoprevention study demonstrates that the herbal plant extract of iwajisha (20 µg/mL) reduced microcystin-LR cytotoxicity in OATP1B3-expressing cells by approximately six times. In addition, 20 µM acteoside, which is one of the major compounds in iwajisha, reduced microcystin-LR cytotoxicity by approximately 7.4 times. Acteoside could also reduce the cytotoxicity of other compounds, such as okadaic acid and nodularin, which are both substrates of OATP1B3 and inhibitors of PP1/PP2A. To investigate the mechanism by which the cytotoxicity of microcystin-LR is attenuated by acteosides, microcystin-LR and microcystin-LR-binding proteins in cells were examined after microcystin-LR and acteosides were co-exposed. Thus, acteoside noncompetitively inhibited microcystin-LR uptake by OATP1B3-expressing cells. Furthermore, acteoside inhibited the intracellular interaction of microcystin-LR with its binding protein(s), including the 22 kDa protein. Furthermore, using immunoblot analysis, acteoside induced the phosphorylation of extracellular signal-regulated kinase (ERK), which is one of the survival signaling molecules. These results suggest that acteoside reduces microcystin-LR cytotoxicity through several mechanisms, including the inhibition of microcystin-LR uptake via OATP1B3, and decreased interaction between microcystin-LR and its binding protein(s), and that ERK signaling activation contributes to the attenuation effect of acteoside against microcystin-LR cytotoxicity.

Activated Carbon-Based Immunochromatographic Strip Test for the Rapid Qualitative Analysis of Swertiamarin and Sweroside

Background

Swertia japonica (S. japonica) is a medicinal plant that belongs to the Gentianaceae family. Several reports confirm the biological effects of the S. japonica extract. This plant is used mainly as a digestive stimulant, appetite stimulant, and gastrointestinal disease remedy in Japan. Secoiridoid glycosides are a group of compounds related to the beneficial effects of this plant.

Objective

We developed an immunochromatographic strip test for major secoiridoid glycosides, such as swertiamarin (SM) and sweroside (SS) detection.

Methods

We fabricated an immunoprobe using activated carbon as a reporter molecule and a monoclonal antibody against SM and SS (MAb D2) as a detection molecule. The test and control zones of the strip test contained SM-cBSA and Goat pAb anti-mouse IgM HRP conjugate, respectively. The immunoprobe reacted competitively with free SM and/or SS and immobilized SM-cBSA. The results were read and interpreted by the black spot intensity in the test zone.

Results

We succeeded in developing a strip test system with a detection limit (LOD) of 12.5 µg/mL. The selectivity and reliability evaluation revealed that the strip test is suitable for detecting SM and SS in S. japonica. The result was ready to be read in 30 min.

Conclusions

This method can be a useful tool for the screening of biologically active S. japonica samples for further preparation of traditional medicine.

Highlights

To the best of our knowledge, this is the first immunochromatographic strip test developed for the detection of SM and SS in S. japonica samples.

A monoclonal antibody-based indirect competitive enzyme-linked immunosorbent assay to quantify swertiamarin and related compounds in Swertia japonica Makino

INTRODUCTION

Swertia japonica Makino (S. japonica) has a long history of use as a folk medicine, and it is one of the three essential Japanese folk medicines. S.japonica has been reported to have various biological activities. The biologically active secoiridoid glycoside swertiamarin (SM) has been isolated from S. japonica. The efficacy of this plant is attributed to SM and related secoiridoid glycosides. To control the quality of S. japonica for medicinal use, a method for the determination of SM and other secoiridoid glycosides in the plant is needed.

OBJECTIVE

To produce an anti-SM monoclonal antibody (MAb) and develop an indirect competitive enzyme-linked immunosorbent assay (icELISA) for S. japonica standardisation and quality control.

METHODOLOGY

SM was conjugated to cationised bovine serum albumin (cBSA), and the SM-cBSA conjugate was used to immunise BALB/c mice. Splenocytes from the immunised mice were then fused with SP2/0 myeloma cells to produce hybridoma cells that expressed anti-SM MAb.

RESULTS

The developed icELISA was sufficiently sensitive and had a quantitative range of 0.78 to 12.5 μg/mL. Coefficients of variation below 10% indicated good repeatability. Recoveries in a spike and recovery assay ranged from 91.84% to 115.50%, which confirmed that the icELISA was accurate. The SM content measured using the icELISA was in agreement with the results of a high-performance liquid chromatography-ultraviolet (HPLC-UV) assay.

CONCLUSION

The icELISA is suitable for the high-throughput analysis of SM and other secoiridoid glycosides in S. japonica. The method is fast, economical, and reliable for S. japonica quality control.

Kaempferol and Its Glycoside, Kaempferol 7-O-Rhamnoside, Inhibit PD-1/PD-L1 Interaction In Vitro

Kaempferol (KO) and kaempferol 7-O-rhamnoside (KR) are natural products from various oriental herbs such as Geranii Herba. Previous studies have reported some biological activities of KO and KR; however, their effects on PD-1/PD-L1 interaction have not been reported yet. To elucidate their inhibitory activities on PD-1/PD-L1 protein–protein interaction (PPI), biochemical assays including competitive ELISA and biolayer interferometry (BLI) systems were performed. Cellular PD-1/PD-L1 blocking activity was measured in a co-culture system with PD-1 Jurkat and PD-L1/aAPC CHO-K1 cells by T-cell receptor (TCR) activation-induced nuclear factor of activated T cells (NFAT)-luciferase reporter assay. The detailed binding mode of action was simulated by an in silico docking study and pharmacophore analysis. Competitive ELISA revealed that KO and its glycoside KR significantly inhibited PD-1/PD-L1 interaction. Cellular PD-1/PD-L1 blocking activity was monitored by KO and KR at non-cytotoxic concentration. Surface plasmon resonance (SPR) and biolayer interferometry (BLI) analysis suggested the binding affinity and direct inhibition of KR against PD-1/PD-L1. An in silico docking simulation determined the detailed mode of binding of KR to PD-1/PD-L1. Collectively, these results suggest that KR could be developed as a potent small molecule inhibitor for PD-1/PD-L1 blockade.

Bioactivity of the Geranium Genus: A Comprehensive Review

BACKGROUND

Plants from the Geranium genus, which comprises about 400 species, have been used since ancient times in the practice of traditional medicines throughout the world. Therefore, herbal preparations based on Geranium species have found wide usage for the treatment of a variety of ailments. The aim of this work is to present a review, as comprehensive as possible, of the studies concerning different biological activities of Geranium species.

METHODS

Relevant data were obtained through systematic computer searches from major reputed scientific databases, particularly Web of Science and Scopus. Occasionally, information issued in primary sources not covered by these databases was also included provided published as peer-reviewed literature. This review covers the literature disclosed till the end of 2018.

RESULTS

Accompanying the increasing interest in herbal medicines in general, the evaluation of the biological properties of medicinal plants from the Geranium genus has been addressed thoroughly, mostly over the last two decades. Geranium species are endowed with a number of different biological activities. Herein, we present a survey of the results of the studies concerning these different biological activities.

CONCLUSION

Most studies found in the literature effectively contribute to scientifically validate the beneficial properties of Geranium plants claimed by traditional medicines and medical herbalism and demonstrate that many of them possess evident therapeutic properties.

Antioxidant and Hepatoprotective Effects of Polyphenols in Leaves of Artemisia Princeps Pamp

The leaves of Artemisia princeps Pamp have been used for tea and food in Japan. The polyphenols of the leaves have inhibitory effects against lipid peroxidation and protein fragmentation by free radicals in vitro and an inhibitory effect on galactosamine -lipopolysaccharide induced hepatotoxicity in vivo. The levels of serum glutamic oxaloacetic transaminase and glutamic pyruvic transaminase, lipid peroxidation in serum and liver by hepatotoxity were depressed by polyphenols in A. princeps Pamp. The depression of gluthathione and superoxide dismutase in plasma and liver by hepatotoxity were elevated by polyphenols in A. princeps Pamp. These results demonstrated that polyphenols in A. princeps Pamp have antioxidant and hepatoprotective effects.

Inhibition of HYBID (KIAA1199)-mediated hyaluronan degradation and anti-wrinkle effect of Geranium thunbergii extract

BACKGROUND

Hyaluronan (HA) is an essential constituent of extracellular matrix in the skin. HA reduction in the dermis and overexpression of HYBID (KIAA1199), a key molecule for HA degradation in skin fibroblasts, are implicated in facial skin wrinkling.

AIMS

We aimed to obtain anti-wrinkle agent(s) by screening for inhibition of HYBID-mediated HA degradation.

METHODS

Various plant extracts were screened for inhibition of HA degradation in HYBID-stable transfectants in HEK293 (HYBID/HEK293). Inhibition of HA-degrading activity and HYBID mRNA and protein expression by Geranium thunbergii extract was studied in skin fibroblasts and HYBID/HEK293 cells. Size distribution of newly produced HA was evaluated by preparing metabolically radiolabeled HA in skin fibroblasts. A double-blind, randomized, and placebo-controlled study was performed in healthy Japanese women (n = 21) by topically treating each side of the face with a lotion formulated with G. thunbergii extract or placebo for 8 weeks.

RESULTS

Among the plant extracts tested, only G. thunbergii extract abolished HA depolymerization in skin fibroblasts and HYBID/HEK293 cells by down-regulating HYBID mRNA and protein expression and by inhibiting HYBID-mediated HA-degrading activity. Although untreated skin fibroblasts produced polydispersed HA, G. thunbergii extract-treated cells produced high-molecular-weight HA. Treatment with G. thunbergii extract-formulated lotion significantly improved skin elasticity and reduced skin wrinkling scores at the outer eye corner compared with the placebo formulation.

CONCLUSIONS

Geranium thunbergii extract inhibited HYBID-mediated HA degradation in vitro and showed anti-wrinkle activity in vivo accompanying the improvement in skin elasticity. Our study provides a possible strategy for anti-wrinkle care through inhibition of HYBID-mediated HA degradation.

The inhibitory effects of Geranium thunbergii on interferon-γ- and LPS-induced inflammatory responses are mediated by Nrf2 activation

Geranium thunbergii Sieb. et Zucc. (GT; which belongs to the Geraniaceae family) has been used as a traditional medicine in East Asia for the treatment of inflammatory diseases, including arthritis and diarrhea. However, the underlying mechanisms of the anti-inflammatory effects of GT remain poorly understood. In the present study, we examined the mechanisms responsible for the anti-inflammatory activity of GT in macrophages. The results revealed that GT significantly inhibited the lipopolysaccharide (LPS)- and interferon-γ (IFN-γ)-induced expression of pro-inflammatory genes, such as inducible nitric oxide synthase, tumor necrosis factor-α and interleukin-1β, as shown by RT-PCR. However, the inhibitory effects of GT on LPS- and IFN-γ-induced inflammation were associated with an enhanced nuclear factor erythroid 2-related factor 2 (Nrf2) activity, but not with the suppression of nuclear factor (NF)-κB activity, as shown by western blot analysis. In addition, in bone marrow-derived macrophages (BMDM) isolated from Nrf2 knockout mice, GT did not exert any inhibitory effect on the LPS- and IFN-γ-induced inflammation. Taken together, our findings indicate that the anti-inflammatory effects of GT may be associated with the activation of Nrf2, an anti-inflammatory transcription factor.

In vitro studies of polyphenol compounds, total antioxidant capacity and other dietary indices in a mixture of plants (Prolipid)

The best health and nutrition results can be achieved not only from the consumption of fruits and vegetables with high antioxidant capacities, but also from medicinal plants and herbs. Therefore, in the present investigation, the bioactive compounds (polyphenols and flavonoids) and the radical scavenging capacities of Prolipid, a mixture of herbs, were studied. Water extracts showed relatively high capacity of about 61.5% inhibition with the beta-carotene linoleic acid assay. In order to support the data obtained with beta-carotene-linoleic acid assay, three different antioxidant assays were used: ferric-reducing/antioxidant power, trolox equivalent antioxidant capacity, and 1,1-diphenyl-2-picrylhydrazyl radical with prolonged time of their reactions. It was found that the amounts of polyphenols in water and methanol extracts were 22.849+/-2.267 and 3.241+/-0.325 mg gallic acid equivalent/g dry weight, and the antioxidant capacities in same extracts as determined by the 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) test after 120 min were 275.81+/-27.58 and 62.25+/-6.11 micromole Trolox equivalents (microMTE) g dry weight, respectively. The correlation coefficients between polyphenols and antioxidant capacities of Prolipid with 1,1-diphenyl-2-picrylhydrazyl radical and beta-carotene linoleic acid assay were about 0.97 and 0.98. In conclusion, the bioactivity of Prolipid was high and the total polyphenols were the main contributors to the overall antioxidant capacity. The results of our investigation in vitro are comparable with other medicinal plants and fruits widely used in the treatment of humans without known side effects. Prolipid, a mixture of herbs, can therefore be used as a supplement for nutritional and healthy purposes.

4-Hydroxykobusin Inhibits the Induction of Nitric Oxide Synthase by Inhibiting NF-.KAPPA.B and AP-1 Activation

We recently isolated a novel lignan, 4-hydroxykobusin from Geranium thunbergii (Liu et al., Arch. Pharm. Res., 29, 1109-1113, 2006). Here, we studied its effect on the expression of inducible nitric oxide synthase (iNOS) gene in RAW264.7 cells. 4-Hydroxykobusin inhibited nitric oxide (NO) production in a concentration-dependent manner and blocked the lipopolysaccharide (LPS)-induced expression of inducible nitric oxide synthase (iNOS). To identify the mechanistic basis for its inhibition of iNOS induction, we examined the effect of 4-hydroxykobusin on the transactivation of iNOS gene by luciferase reporter activity using -1.59 kb flanking region. The lignan suppressed the reporter gene activity and the LPS-induced reporter activations of nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) were also significantly blocked by 4-hydroxykobusin. These findings suggest that the inhibition of LPS-induced NO formation by 4-hydroxykobusin is due to its inhibition of NF-kappaB and AP-1 activation.

7,7'-Dihydroxy bursehernin inhibits the expression of inducible nitric oxide synthase through NF-kappaB DNA binding suppression

This study isolated a lignan, 7,7'-dihydroxy bursehernin, from Geranium thunbergii and investigated whether or not the lignan affects the induction of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in RAW264.7 macrophages stimulated with lipopolysaccharide (LPS). The gel shift analysis and luciferase reporter gene assays using the iNOS promoter and nuclear factor-kappaB (NF-kappaB) minimal promoter showed that a treatment with 7,7'-dihydroxy bursehernin reduced the reporter activities and binding of NF-kappaB to the NF-kappaB consensus sequence, while it had no effect on the nuclear translocation of p65 and the phosphorylation/degradation of I-kappaBalpha. It was reported that a few natural compounds directly suppressed the binding activity of the NF-kappaB components to DNA. The NF-kappaB binding activity was not reversed by the in vitro exposure of the nuclear extracts to 7,7'-dihydroxy bursehernin, which suggest that a metabolite(s) of 7,7'-dihydroxy bursehernin might target the binding of the NF-kappaB complex to the DNA binding domain region in the promoter region of the iNOS gene. After incubation of RAW264.7 cells with 7,7-dihydroxy bursehernin for 18h, the levels of parent compound were negligible; while a main metabolite, 4-[4-(n-hydroxy-phenyl)-2,3-dimethyl-buta-1,3-dienyl]-benzene-1,2-diol was detected in cell lysates and culture medium.