Growth inhibitory and apoptosis-inducing effects of allergen-free Rhus verniciflua Stokes extract on A549 human lung cancer cells

A comprehensive review of medicinal Toxicodendron (Anacardiaceae): Botany, traditional uses, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Comprising of about 30 species, the genus Toxicodendron (Anacardiaceae) are mainly distributed in East Asia and North America. Among them, 13 species have been traditionally used as folk medicines in Asia and other parts of the world to treat blood diseases, abnormal bleeding, skin diseases, gastrointestinal diseases, liver diseases, bone injury, lung diseases, neurological diseases, cardiovascular diseases, tonic, cancer, eye diseases, menstrual irregularities, inflammation, rheumatism, diabetes mellitus, rattlesnake bite, internal parasites, contraceptive, vomiting and diarrhea.

AIM OF THE STUDY

To date, no comprehensive review on Toxicodendron has been published and the scientific basis of the traditional medicinal benefits of Toxicodendron have been less reported. Therefore, this review aims to provide a reference for further research and development on medicinal purpose of Toxicodendron by summarizing the works (from 1980 to 2023), and focusing on its botany, traditional uses, phytochemistry and pharmacology.

MATERIALS AND METHODS

The names of the species were from The Plant List Database (http://www.theplantlist.org), World Flora Online (http://www.worldfloraonline.org), Catalogue of Life Database (https://www.catalogueoflife.org/) and Plants for A Future Database (https://pfaf.org/user/Default.aspx). And the search terms "Toxicodendron" and "the names of 31 species and their synonyms" were used to search for information from electronic databases such as Web of Science, Scopus, Google Scholar, Science Direct, PubMed, Baidu Scholar, Springer, and Wiley Online Library. Moreover, PhD and MSc dissertations were also used to support this work.

RESULTS

These species on Toxicodendron are widely used in folkloric medicine and modern pharmacological activities. So far, approximately 238 compounds, mainly phenolic acids and their derivatives, urushiols, flavonoids and terpenoids, are extracted and isolated from Toxicodendron plants, commonly, T. trichocarpum, T. vernicifluum, T. succedaneum, and T. radicans. Among them, phenolic acids and flavonoids are the main compound classes that show pharmacological activities in Toxicodendron plants both in vitro and in vivo. Furthermore, the extracts and single compounds of these species show a wide range of activities, such as antioxidant, antibacterial, anti-inflammatory, anti-tumor, liver protection, fat reduction, nerve protection, and treatment of blood diseases.

CONCLUSIONS

Selected species of Toxicodendron have been used as herbal medicines in the Southeast Asian for a long time. Furthermore, some bioactive constituents have been identified from them, so plants in this genus may be potential new drugs. The existing research on Toxicodendron has been reviewed, and the phytochemistry and pharmacology provide theoretical basis for some of the traditional medicinal uses. Therefore, in this review, the traditional medicinal, phytochemical and modern pharmacology of Toxicodendron plants are summarized to help future researchers to find new drug leads or to get a better understanding of structure-activity relationships.

Evaluation of the Antifungal Effect of Rhus verniciflua Stokes Extract for Oral Application Potential

Background and Objectives: This study confirms the possibility of using Rhus verniciflua Stokes (RVS) extract as a natural treatment for oral candidiasis. Materials and Methods: RVS was extracted with 70% ethanol to examine the antioxidant activity through polyphenol, flavonoid content, and DPPH (1,1-diphenyl-2-picrylhydrazyl). To evaluate the antifungal effect against Candida albicans (C. albicans; KCTC 7965/ATCC 10231) and evaluate the stability of RVS, a water-soluble tetrazolium salt (WST-1) assay was performed in human keratinocytes (HaCaT). Results: The findings revealed that RVS extract has fairly high antioxidant activity. The clear zones of the RVS extract against C. albicans increased in diameter due to the inhibition of fungal growth at higher concentrations. Treatment with the 1.25 mg/mL RVS extract had a more than 99% antifungal effect against C. albicans, and the 20 mg/mL RVS extract had a 100% antifungal effect. The WST-1 assay showed that the RVS extract induced low cell viability in the HaCaT cells, which inhibited their proliferation, and the RVS extract is also toxic to normal cells. Conclusions: Although the RVS extract with high antioxidant activity showed clear antifungal activity against C. albicans, it exhibited a low survival rate. Therefore, the development of a safe natural antibiotic is necessary.

Safety assessment of oil extracted from lacquer (Toxicodendron vernicifluum (Stokes) F.A. Barkley) seed: acute and subchronic toxicity studies in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Toxicodendron vernicifluum (Stokes) F.A. Barkley (RVS) is an economic tree species and widely distributed in East Asia. Wood parts and raw lacquers of RVS have been used in coatings, herbal medicines or food supplements, and the leaves, flowers, roots, and fruits of RVS are also widely used in medicine traditionally. Lacquer seed oil (LSO) has potential health benefits and has not previously been evaluated for safety.

AIM OF THE STUDY

The aim of the present study was to investigate the toxicological potential of LSO by acute and subchronic toxicity tests.

MATERIALS AND METHODS

The characterization of fatty acids of the LSO was carried out by gas chromatography. In the acute toxicity study, LSO was administered at single doses of 5000 or 10000 mg/kg by oral gavage. The subchronic toxicity study was conducted by daily oral administration of LSO at doses of 1250, 2500 and 5000 mg/kg/day for 30 consecutive days. The animals were evaluated for clinical observations, body weight, organ weight, feed consumption, biochemical and hematological parameters, and liver, lung, and kidney histology.

RESULTS

There were no mortality and toxic changes were observed in acute toxicity study. The results of subchronic toxicity showed no toxicologically significant changes in clinical observations, body weight, organ weight, biochemical or hematological parameters. Histopathologic results indicated slight hepatic steatosis and inflammatory infiltration in the rats of 5000 mg/kg/day LSO treated group. However, the histopathologic observation was not confirmed by hepatic biochemical analysis.

CONCLUSIONS

These results suggested that the LD₅₀ of LSO is over 10000 mg/kg and LSO is non-toxic for SD rats in acute toxicity study. The no observed adverse effect level (NOAEL) of LSO in rats is considered to be 5000 mg/kg/day, and liver is the potential target organ of LSO for 30-day subchronic toxicity study.

Potential anticancer activities of Rhus coriaria (sumac) extract against human cancer cell lines

Therapeutic strategies of plant origin are a better choice as both dietary plant products or its isolated active constituents against the development and progression of cancer. The present study aims to evaluate the anticancer activity of sumac (Rhus coriaria) against different human cancer MCF-7, PC-3, and SKOV3 cell lines. In addition, the study tries to explore a prospective mechanism of action, assessment of in vitro enzyme-inhibitory capacity of sumac extract against hCA I, II, IX, and XII. In the present study, the potential antitumor effects of sumac (Rhus coriaria) were explored in the human cancer cell lines; MCF-7, PC-3, and SKOV3 using in vitro assays. Apoptotic, cell survival, ELISA immunoassays were also conducted to reveal the inhibitory effects of sumac extract against hCA I, II, IX, and XII. In addition, both Clioquinol and Acetazolamide (AZM) were used as standards to explore the in vitro enzyme-inhibitory capacity of sumac extract against hCA I, II, IX, and XII. The hydro-alcoholic extract of R. coriaria (Sumac) was subjected to phytochemical analysis using GC/MS assays. Sumac at non-cytotoxic doses of 50 and 100 µM significantly modulates the growth of the MCF-7, PC-3, and SKOV3 cancer cells with a higher inhibitory effect and selectivity to carbonic anhydrase (CA) isoforms; hCA I, II, hCA IX, and XII. The data showed that sumac at doses of 50 and 100 µM significantly inhibited the growth, proliferation, and viability of cancer cells by activating the apoptotic process via caspase-3 overexpression and the regulation of Bcl-2 anti-apoptotic protein.

Traditional uses, phytochemistry, and pharmacology of Toxicodendron vernicifluum (Stokes) F.A. Barkley - A review

ETHNOPHARMACOLOGICAL RELEVANCE

Toxicodendron vernicifluum (Stokes) F.A. Barkley (syn. Rhus verniciflua or vernicifera Stokes, Anacardiaceae) (RVS), the lacquer tree, also known as sumac, has been used in China, Japan and South Korea for thousands of years as a highly durable coating material and a traditional herbal medicine, which contains medicinal ingredients with anti-tumor, anti-inflammatory, antiviral, and anti-rheumatic activities.

AIM OF THIS REVIEW

This review intends to provide a comprehensive and critical appraisal of RVS, including its phytochemical data, botanical and pharmacological literature that support its therapeutic potential in treatment on human diseases, with emphasis on the isolation of natural occurring compounds and detailed pharmacological investigations.

MATERIALS AND METHODS

Specific information of RVS was collected by using the key words "Toxicodendron vernicifluum", "Rhus verniciflua Stokes", "Rhus vernicifera Stokes" and "Lacquer tree" through published scientific materials (including PubMed, ScienceDirect, Wiley, ACS, CNKI, Scifinder, Springer, Web of Science, Google Scholar, and Baidu Scholar) and other literature sources.

RESULTS

The major phytoconstituents, 175 of which are presented in this review, including flavonoids, urushiols, terpenes, phenolic acids and other types of compounds, of which flavonoids and urushiols are main components. The extracts and isolates purified from RVS showed a wide range of in vitro and in vivo pharmacological effects, such as anti-cancer, anti-oxidation, anti-inflammatory, antimicrobial, tyrosinase inhibition and so on.

CONCLUSION

The modern pharmacological research of RVS mainly focus on the pharmacological effects of crude extract or active constituents, of which the flavonoids are widely studied. However, there are few reports on the relationship between pharmacological effects and their structures. And at present, there is still a lack of researches that are of both effective and in-depth. Meanwhile, there is little research on quality control. Apart from the wood and lacquer, other botanical parts also need to be explored further. In addition to phenolic compounds, the study on other types of components in T. vernicifluum would start more sparks for the discovery of new bioactive principles.

Fermented-Rhus verniciflua extract ameliorate Helicobacter pylori eradication rate and gastritis

An antibacterial effect of fermented-Rhus verniciflua extract (FRVE), an urushiol-free extract fermented by Fomitella fraxinea, on Helicobacter pylori was evaluated in mice. Minimal inhibitory concentration of FRVE against H. pylori eradication was checked with serial dilution method in vitro. H. pylori infection-induced mice were utilized to determine the effect of oral administration of FRVE with/without standard triple therapy (STT: metronidazole, omeprazole, and clarithromycin) on H. pylori colonization and gastric inflammation. H. pylori was clearly eradicated by FRVE at a concentration of ≥2 mg/ml in vitro. In animal study, FRVE at a concentration of ≥6 mg/ml significantly reduced colonized H. pylori grading (0.2 vs. 2.2, p < .01) and improved gastric inflammation (0.4 vs. 1.6, p < .01) compared to control. STT with FRVE (3 mg/ml) exerted synergistic effect on both H. pylori colonization grade (STT, 0.6 ± 0.9; FRVE, 1.4 ± 0.5; STT + FRVE, 0.8 ± 0.4) and gastric inflammation (STT, 0.4 ± 0.5; FRVE, 1.4 ± 0.5; STT + FRVE,1.0 ± 0.1) compared with single therapy (p < .01). H. pylori eradication rate of FRVE (6 mg/ml) was higher than that of STT (60% vs. 20%). FRVE has potential antibacterial activity against H. pylori infection and can be used as an additional therapy on STT.

Toxicodendron vernicifluum Stokes extract inhibits solid tumor growth and lung metastasis of 4T1 murine mammary carcinoma cells in BALB/c mice

Toxicodendron vernicifluum Stokes has long been used as a food supplement and traditional herbal medicine in East Asia. We applied a new extraction method to produce Toxicodendron vernicifluum Stokes extract (TVSE), that doesn't contain urushiol (an allergenic toxin) but dose have higher levels of some flavonoids such as fustin and fisetin. This study was conducted to investigate the anticancer effects of TVSE in an in vivo system. Fifty BALB/c mice were acclimated for one week and then injected with 4T1 murine mammary carcinoma cells in mammary fat pads. After 7 days, the mice were randomly divided into 5 groups, and orally administered with 0, 50, 100, 200 or 400 mg of TVSE/kg body weight (BW)/day for 20 days. TVSE reduced tumor volume and weight dose-dependently. The expression of Ki67 was significantly reduced and the number of TUNEL-positive apoptotic cells was significantly increased in the TVSE-treated group over 100 mg/kg BW/day. While tumor nodules were not found in the liver, but only in lungs, the number of tumor nodules was reduced in a dose-dependent manner in the TVSE treated groups compared to the control group. In breast tumors, expression of platelet endothelial cell adhesion molecule (PECAM-1) and vascular endothelial growth factor (VEGF) was reduced by TVSE treatment. TVSE treatment significantly suppressed mRNA expression in tumors of matrix metalloproteinase (MMP)-2, tissue inhibitor of metalloproteinase (TIMP)-1, urokinase-type plasminogen activator (uPA), intercellular adhesion molecule (ICAM)-1, and vascular cell adhesion molecule (VCAM)-1 while increasing plasminogen activator inhibitor (PAI)-1. These results suggest that TVSE is potentially beneficial for the suppression of breast cancer growth and its-associated lung metastasis.

Rhus verniciflua Stokes extract suppresses migration and invasion in human gastric adenocarcinoma AGS cells

BACKGROUND/OBJECTIVES

Many studies have suggested that Rhus verniciflua Stokes (RVS) and its extract are anticancer agents. However, RVS had limited use because it contains urushiol, an allergenic toxin. By improving an existing allergen-removal extraction method, we developed a new allergen-free Rhus verniciflua Stokes extract (RVSE) with higher flavonoid content. In this study, we examined whether RVSE inhibits the ability of AGS gastric cancer cells to migrate and invade.

MATERIALS/METHODS

The flavonoids content of RVSE was analyzed by HPLC. The effects of RVSE on migration and invasion in AGS cells were analyzed by each assay kit. Matrix metalloproteinase (MMP)-9, plasminogen activator inhibitor-1 (PAI-1) and urokinase-type plasminogen activator (uPA) protein expression was analyzed by protein antibody array. The Phosphorylation of signal transducer and activator of transcription (STAT) 3 were assayed by Western blot analysis.

RESULTS

RVSE treatment with 0-100 μg/mL dose-dependently reduced the ability of AGS cells to migrate and invade. Notably, treatment with RVSE strongly inhibited the expression of MMP-9 and uPA and the phosphorylation of STAT3. In contrast, RVSE treatment dramatically increased the expression of PAI-1. These results indicate that the inhibition of MMP-9 and uPA expression and STAT3 phosphorylation and the stimulation of PAI-1 expression contributed to the decreased migration and invasion of AGS cells treated with RVSE.

CONCLUSIONS

These results suggest that RVSE may be used as a natural herbal agent to reduce gastric cancer metastasis.

Immune Checkpoint PD-1/PD-L1 CTLA-4/CD80 are Blocked by Rhus verniciflua Stokes and its Active Compounds

The bark of Rhus verniciflua Stokes (RVS) has been used to treat cancer in Korean herbal medicine. When we screened for PD-1 and CTLA-4 immune checkpoint inhibitors (PD-1/PD-L1 CTLA-4/CD80) from around 800 herbal extracts using competitive Enzyme-Linked Immunosorbent Assay (ELISA), we found that RVS blocked both the PD-1/PD-L1 and the CTLA-4/CD80 interactions. To identify the active compounds from RVS, we performed bioactivity-guided fractionation, and the ethyl acetate (EtOAc) fraction of RVS proved to be the most effective at blocking the PD-1/PD-L1 and CTLA-4/CD80 interactions. In addition, we isolated and identified 20 major compounds in the EtOAc fraction of RVS and then examined the blocking effects of these 20 compounds on PD-1/PD-L1 and CTLA-4/CD80. Among them, four compounds [eriodictyol (7) > fisetin (9) > quercetin (18) > liquiritigenin (13)] blocked the interaction of PD-1/PD-L1 on competitive ELISA. In addition, four different compounds [protocatechuic acid (2) > caffeic acid (19) > taxifolin (5) > butin (6)] blocked the interaction of CTLA-4/CD80. Our findings suggest that RVS and its components could be used as a potential immune checkpoint inhibitor blockade and could be developed for immuno-oncological therapeutics.

Extract of Rhus verniciflua Stokes Induces p53-Mediated Apoptosis in MCF-7 Breast Cancer Cells

Rhus verniciflua Stokes has long been used as a food supplement and traditional herbal medicine for various ailments in East Asia. We evaluated the anticancer effects of Rhus verniciflua Stokes extract (RVSE) on MCF-7 cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, annexin V/7-AAD staining, and western blotting. In addition, the gallic acid content of RVSE was assayed using high-performance liquid chromatography. RVSE inhibited the growth of MCF-7 cells in a dose-dependent manner by inducing apoptosis in the sub-G1 phase. RVSE also significantly increased the number of apoptotic cells and increased the expression of p53 and p21 in a dose-dependent manner. Furthermore, RVSE treatment increased the Bax:Bcl-2 ratio and the levels of apoptosis-related factors, such as cleaved caspase-3 and -9 and PARP, in MCF-7 cells. Our findings suggest that the proapoptotic effect of RVSE on MCF-7 cells is mediated by p53, p21, and the intrinsic mitochondrial cascade. Thus, RVSE shows promise for the prevention and treatment of breast cancer.

Synthesis and Evaluation of C15 Triene Urushiol Derivatives as Potential Anticancer Agents and HDAC2 Inhibitor

A series of C15 triene urushiol derivatives were synthesized and evaluated for their anti-HepG2 aggregation in vitro. The results indicated that all compounds had an effective anti-HepG2 vitality. Compound 1 was a potent inhibitor of HepG2 with IC₅₀ of 7.886 μM and 150 μM against LO2. Moreover, compound 1 increased the apoptosis of HepG2. Compound 1’s thiol sulfur formed hydrogen bonding interactions with Gly154 and Tyr308, respectively, and made it bound more closely to HDAC2. In addition, it also formed hydrophobic interactions with the residues His33, Pro106, Val107, Gly154, Phe155, and His183, and was provided with a strong van der Waals force by the hydrophobic action.