The Clinical Effects of Dendropanax Morbifera on Postmenopausal Symptoms: Review Article

Dendropanoxide Attenuates High Glucose-induced Oxidative Damage in NRK-52E Cells via AKT/mTOR Signaling Pathway

Hyperglycemia is a potent risk factor for the development and progression of diabetes-induced nephropathy. Dendropanoxide (DPx) is a natural compound isolated from Dendropanax morbifera (Araliaceae) that exerts various biological effects. However, the role of DPx in hyperglycemia-induced renal tubular cell injury remains unclear. The present study explored the protective mechanism of DPx on high glucose (HG)-induced cytotoxicity in kidney tubular epithelial NRK-52E cells. The cells were cultured with normal glucose (5.6 mM), HG (30 mM), HG + metformin (10 µM), or HG + DPx (10 µM) for 48 h, and cell cycle and apoptosis were analyzed. Malondialdehyde (MDA), advanced glycation end products (AGEs), and reactive oxygen species (ROS) were measured. Protein-based nephrotoxicity biomarkers were measured in both the culture media and cell lysates. MDA and AGEs were significantly increased in NRK-52E cells cultured with HG, and these levels were markedly reduced by pretreatment with DPx or metformin. DPx significantly reduced the levels of kidney injury molecule-1 (KIM-1), pyruvate kinase M2 (PKM2), selenium-binding protein 1 (SBP1), or neutrophil gelatinase-associated lipocalin (NGAL) in NRK-52E cells cultured under HG conditions. Furthermore, treatment with DPx significantly increased antioxidant enzyme activity. DPx protects against HG-induced renal tubular cell damage, which may be mediated by its ability to inhibit oxidative stress through the protein kinase B/mammalian target of the rapamycin (AKT/mTOR) signaling pathway. These findings suggest that DPx can be used as a new drug for the treatment of high glucose-induced diabetic nephropathy.

Dendropanoxide, a Triterpenoid from Dendropanax morbifera, Ameliorates Hepatic Fibrosis by Inhibiting Activation of Hepatic Stellate Cells through Autophagy Inhibition

Hepatic fibrosis results from chronic liver damage and is characterized by excessive accumulation of extracellular matrix (ECM). In this study, we showed that dendropanoxide (DPX), isolated from Dendropanax morbifera, had anti-fibrotic effects on hepatic fibrosis by inhibiting hepatic stellate cell (HSC) activation. DPX suppressed mRNA and protein expression of α-SMA, fibronectin, and collagen in activated HSCs. Moreover, DPX (40 mg/kg) treatment significantly lowered levels of liver injury markers (aspartate aminotransferase and alanine transaminase), expression of fibrotic markers, and deposition of ECM in a carbon tetrachloride-induced mouse model. Anti-fibrotic effects of DPX were comparable to those of silymarin in a hepatic fibrosis mouse model. As a possible mechanism of anti-fibrotic effects, we showed that DPX inhibited autophagosome formation (LC3B-II) and degradation of p62, which have important roles in HSC activation. These findings suggest that DPX inhibits HSC activation by inhibiting autophagy and can be utilized in hepatic fibrosis therapy.

Effectiveness and Safety of Hwangchil-Unripe Bokbunja Extract Mixture on Blood Pressure: A Randomized Double-Blind Placebo-Controlled Clinical Trial

From 25% to 50% of adults are affected by prehypertension. Prehypertension increases the risk of hypertension and affects the heart and systemic vascular system. Food mixed tree essence of Dendropanax morbifera called Hwangchil in Korean and immature fruit of Rubus coreanus, called Bokbunja (HDR-2), have been studied for safety and effectiveness against prehypertension studies. This study was a randomized double-blind placebo-controlled multicenter clinical trial lasting 19 months from October 2017 to May 2019. The 88 subjects who enrolled in the study were divided into two groups. The treatment group was provided HDR-2 and the other group took a placebo. Both HDR-2 and placebo were in the form of capsules, and the dose was 900 mg per day. Subjects took HDR-2 or placebo capsules once a day for 8 weeks before dinner. The primary observational indicators were systolic blood pressure (SBP) and diastolic blood pressure (DBP), and the secondary observational indicators were mean arterial pressure (MAP), mean pulse pressure, pulse rate, angiotensin-converting enzyme activity, renin activity, aldosterone, and highly sensitive-C reactive protein. The number of measurements was three times: the first visit in the screening week, the second visit in 4 weeks, and the third visit was after 8 weeks. Significant study results showed that the SBP and MAP of the HDR-2 group after 8 weeks were lower than those of the placebo group. Adverse events were not significantly different between the two groups. In conclusion, these results suggest that HDR-2 may be a useful intervention for the management of prehypertension. The protocol was registered in the Korean Clinical Trial Registration system (http://cris.nih.go.kr; registration number: KCT0004300).

Neuroprotective effects of Dendropanax morbifera leaves on glutamate-induced oxidative cell death in HT22 mouse hippocampal neuronal cells

ETHNOPHARMACOLOGICAL RELEVANCE

Dendropanax morbifera (DM) has long been used as a traditional herbal medicine for migraines. Glutamate toxicity and oxidative stress have emerged as the possible triggers implicated in migraine pathogenesis.

AIM OF THE STUDY

We aimed to examine the neuroprotective effects of DM leaves (DML) on glutamate-induced oxidative cell death in HT22 mouse hippocampal neuronal cells.

MATERIALS AND METHODS

Molecular authentication of DML was assessed using DNA barcoding analysis. Four different solvent extracts of DML were prepared and subjected to antioxidant activity and phytochemical assays. Neuroprotective effects of DML extracts were evaluated using relevant biochemical and imaging assays that measure cell viability/death, ROS generation, Ca²⁺ levels, mitochondrial dysfunction, and AIF nuclear translocation.

RESULTS

The sequences of matK, rbcL, atpF-H, and psbK-I in DML were identical with those in voucher specimens, confirming that DML was indeed D. morbifera. The ethyl acetate extract of DML (DMLE) showed the highest flavonoid and phenolic content, and prominent DPPH/superoxide radical scavenging and reducing power activities. In the HT22 cell model, glutamate was shown to be the causative agent for apoptotic cell death via elevation of intracellular ROS and Ca²⁺ levels, induction of mitochondrial depolarization and membrane permeabilization, and translocation of AIF to the nucleus. Of note, N-acetyl-L-cysteine and necrostatin-1, but not z-VAD-fmk, completely prevented glutamate-induced cell death, implying that oxidative stress and AIF translocation were pivotal in glutamate cytotoxicity. DMLE significantly recovered glutamate-induced apoptotic cell death in a concentration-dependent manner. It completely inhibited intracellular/mitochondrial ROS generation, the elevation of Ca²⁺ levels, and mitochondrial dysfunction induced by glutamate during early exposure within 8 h. It significantly reversed subsequent AIF nuclear translocation after 12 h of treatment. Antioxidant activities of DMLE may be the protective mechanism that regulates homeostatic balance of ROS and Ca²⁺ as well as maintains mitochondrial function.

CONCLUSIONS

DMLE shows significant neuroprotective effects against glutamate-induced oxidative neuronal cell death. Therefore, DM could be a potential therapeutic candidate for neurological disorders propagated by glutamate toxicity.

Dendropanax morbifera Leaf Polyphenolic Compounds: Optimal Extraction Using the Response Surface Method and Their Protective Effects against Alcohol-Induced Liver Damage

The response surface methodology was used to optimally extract the antioxidant substances from Dendropanax morbifera leaves. The central composite design was used to optimally analyze the effects of ethanol concentration, sample to solvent ratio, extraction temperature, and extraction time on the total flavonoids (TF) content, ferric reducing antioxidant power (FRAP), and Trolox equivalent antioxidant capacity (TEAC). All three parameters were largely influenced by the ethanol concentration and extraction temperature, while TEAC was also influenced by the sample to solvent ratio. The maximum values of TF content, FRAP, and TEAC were achieved under the following extraction conditions: 70% ethanol, 1:10 sample to solvent ratio, 80 °C, and 14 h. The D. morbifera leaf extracts (DMLE) produced under these optimum extraction conditions were investigated to determine their preventive effects on alcohol-induced liver injury. The DMLE was shown to prevent liver injury by scavenging the reactive oxygen species generated by alcohol. In addition, composition analysis of DMLE found high contents of chlorogenic acid and rutin that were determined to inhibit alcoholic liver injury. The findings of this study suggest that DMLE could prove useful as a functional food product supplement to prevent liver injury caused by excessive alcohol consumption.

Dendropanax morbifera Protects against Renal Fibrosis in Streptozotocin-Induced Diabetic Rats

The aquatic extract of Dendropanax morbifera (DP) is typically consumed as a beverage in Korea and China and is also used in various traditional medicines. However, the functional role of DP on diabetes-induced renal fibrosis is unclear. Here, the protective effects of DP extract against diabetes-induced renal fibrosis were evaluated. Streptozotocin (STZ, 60 mg/kg) was injected intraperitoneally in rats to induce diabetes. After 5 days, DP extract (25 mg/kg/day) and metformin (50 mg/kg/day) were administered orally to diabetic rats for 28 days. DP administration protected both body and organ weight loss in STZ-treated diabetic rats. Significant improvements in serum blood urea nitrogen (BUN), creatinine, and oxidative stress parameters were observed in diabetic rats by DP administration. DP extract markedly protected diabetic-induced histopathological damages in the kidney and pancreas. A significant reduction was observed in microalbumin, kidney injury molecule-1 (KIM-1), selenium binding protein-1 (SBP1), and pyruvate kinase muscle isozyme M2 (PKM2) levels in the urinary excretion of diabetic rats after the administration of DP extract. The expression of pro-inflammatory cytokines and fibrosis marker levels were significantly reduced in the kidney of diabetic rats. Our results strongly indicate that DP extract exhibits protective activity against diabetes-induced renal fibrosis through ameliorating oxidative stress and inflammation. Therefore, we suggest that DP extract can be used as a preventive agent on the progression of diabetic nephropathy and renal fibrosis.

Dendropanax morbifera Ameliorates Thioacetamide-Induced Hepatic Fibrosis via TGF-β1/Smads Pathways

Hepatic fibrosis, characterized by persistent deposition of extracellular matrix (ECM) proteins, occurs in most types of chronic liver disease. The prevention of liver damage using extract of Dendropanax morbifera has been widely studied, but its molecular mechanism on the therapeutic efficacy of hepatic fibrosis is unclear. The aim of this study was to assess whether aquatic extract (DM) of D. morbifera ameliorates thioacetamide (TAA)-induced hepatic fibrosis. Hepatic fibrosis was induced by an intraperitoneal (i.p.) injection (150 mg/kg, twice per week) of TAA for 6 weeks. DM (50 mg/kg/day) or silymarin (50 mg/kg/day) was administered daily for 6 weeks. DM markedly reduced serum AST, ALT, ALP, and r-GTP in TAA-treated rats. DM significantly ameliorated the total glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) activity in TAA-treated rats. In particular, DM significantly reduced expression of α-SMA, type I collagen, vimentin, TGF-β1 and p-Smad2/3 in hepatic fibrosis rats. The protective effects of DM on progression of hepatic fibrosis were clearly shown by detecting 4-hydroxyproline concentration and histopathological examination in the liver. Therefore, our data suggest that DM dramatically prevented hepatic fibrosis by inhibiting oxidative stress and the TGF-β1/Smads signaling pathways.

Optimization of the Extraction Conditions and Biological Evaluation of Dendropanax morbifera H. Lev as an Anti-Hyperuricemic Source

Dendropanax morbifera H. Levis a medicinal plant native to South Korea, East Asia, and South America. Among some 75 species, one species grows in Korea. In previous studies, D. morbifera extracts with anti-oxidant, anti-inflammatory, anti-complementary and anti-cancer activities were reported. The present study aims to investigate optimization of extraction and evaluation of anti-hyperuricemic effects of D. morbifera leaf and the phytochemicals contained therein. Ethanol and hexane extract were found to display the best xanthine oxidase inhibition among six types of solvent and water extract. The antioxidant effect of the ethanol extract was superior to that of the hexane extract. The DPPH radical scavenging effect of the ethanol and hexane extracts were 81.52 ± 1.57% and 2.69 ± 0.16. The reducing power of the ethanol and hexane extracts were 9.71 ± 0.15 and 0.89 ± 0.01 mg/g equivalent of gallic acid. Total phenols of the ethanol and hexane extracts were 6.53 ± 0.16 and 0.63 ± 0.001 mg/g equivalent of gallic acid. In addition, we compared the two marker compounds from D. morbifera, chlorogenic acid and rutin, which were determined in the ethanol extract at 0.80 ± 0.03% and 0.52 ± 0.01%, respectively. We found that the ethanol extracts showed better xanthine oxidase inhibition than hexane extracts. Especially, ethanol extracts showed higher antioxidant activity than hexane extracts. Based on these results, we selected the ethanol extract as an effective xanthine oxidase inhibitor and confirmed whether ethanol extracts showed xanthine oxidase inhibition in animal experiments. The in vivo mouse study demonstrated that ethanol extract of D. morbifera leaf at the dose of 300 mg/kg could inhibit blood/hepatic xanthine oxidase activity and this result shows that the xanthine oxidase inhibitory activity in vitro is reproduced in vivo. The present study showed that ethanol extract was optimal xanthine oxidase inhibitor which can be applied to prevent diseases related to hyperuricemia.