Dihydrocelastrol induces antitumor activity and enhances the sensitivity of bortezomib in resistant multiple myeloma by inhibiting STAT3-dependent PSMB5 regulation.

Multiple myeloma (MM) is characterized by excessive aggregation of B-cell-derived malignant plasma cells in the hematopoietic system of bone marrow. Previously, we synthesized an innovative molecule named dihydrocelastrol (DHCE) from celastrol, a triterpene purified from medicinal plant Tripterygium wilfordii. Herein, we explore the therapeutic properties and latent signal transduction mechanism of DHCE action in bortezomib (BTZ)-resistant (BTZ-R) MM cells. In this study, we first report that DHCE shows antitumor activities in vitro and in vivo and exerts stronger inhibitory effects than celastrol on BTZ-R cells. We find that DHCE inhibits BTZ-R cell viability by promoting apoptosis via extrinsic and intrinsic pathways and suppresses BTZ-R MM cell proliferation by inducing G0/G1 phase cell cycle arrest. In addition, inactivation of JAK2/STAT3 and PI3K/Akt pathways are involved in the DHCE-mediated antitumor effect. Simultaneously, DHCE acts synergistically with BTZ on BTZ-R cells. PSMB5, a molecular target of BTZ, is overexpressed in BTZ-R MM cells compared with BTZ-S MM cells and is demonstrated to be a target of STAT3. Moreover, DHCE downregulates PSMB5 overexpression in BTZ-R MM cells, which illustrates that DHCE overcomes BTZ resistance through increasing the sensitivity of BTZ in resistant MM via inhibiting STAT3-dependent PSMB5 regulation. Overall, our findings imply that DHCE may become a potential therapeutic option that warrants clinical evaluation for BTZ-R MM.

ETCM v2.0: An update with comprehensive resource and rich annotations for traditional Chinese medicine.

Existing traditional Chinese medicine (TCM)-related databases are still insufficient in data standardization, integrity and precision, and need to be updated urgently. Herein, an Encyclopedia of Traditional Chinese Medicine version 2.0 (ETCM v2.0, http://www.tcmip.cn/ETCM2/front/#/) was constructed as the latest curated database hosting 48,442 TCM formulas recorded by ancient Chinese medical books, 9872 Chinese patent drugs, 2079 Chinese medicinal materials and 38,298 ingredients. To facilitate the mechanistic research and new drug discovery, we improved the target identification method based on a two-dimensional ligand similarity search module, which provides the confirmed and/or potential targets of each ingredient, as well as their binding activities. Importantly, five TCM formulas/Chinese patent drugs/herbs/ingredients with the highest Jaccard similarity scores to the submitted drugs are offered in ETCM v2.0, which may be of significance to identify prescriptions/herbs/ingredients with similar clinical efficacy, to summarize the rules of prescription use, and to find alternative drugs for endangered Chinese medicinal materials. Moreover, ETCM v2.0 provides an enhanced JavaScript-based network visualization tool for creating, modifying and exploring multi-scale biological networks. ETCM v2.0 may be a major data warehouse for the quality marker identification of TCMs, the TCM-derived drug discovery and repurposing, and the pharmacological mechanism investigation of TCMs against various human diseases.

Bioactive compounds from Huashi Baidu decoction possess both antiviral and anti-inflammatory effects against COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic is an ongoing global health concern, and effective antiviral reagents are urgently needed. Traditional Chinese medicine theory-driven natural drug research and development (TCMT-NDRD) is a feasible method to address this issue as the traditional Chinese medicine formulae have been shown effective in the treatment of COVID-19. Huashi Baidu decoction (Q-14) is a clinically approved formula for COVID-19 therapy with antiviral and anti-inflammatory effects. Here, an integrative pharmacological strategy was applied to identify the antiviral and anti-inflammatory bioactive compounds from Q-14. Overall, a total of 343 chemical compounds were initially characterized, and 60 prototype compounds in Q-14 were subsequently traced in plasma using ultrahigh-performance liquid chromatography with quadrupole time-of-flight mass spectrometry. Among the 60 compounds, six compounds (magnolol, glycyrrhisoflavone, licoisoflavone A, emodin, echinatin, and quercetin) were identified showing a dose-dependent inhibition effect on the SARS-CoV-2 infection, including two inhibitors (echinatin and quercetin) of the main protease (Mpro), as well as two inhibitors (glycyrrhisoflavone and licoisoflavone A) of the RNA-dependent RNA polymerase (RdRp). Meanwhile, three anti-inflammatory components, including licochalcone B, echinatin, and glycyrrhisoflavone, were identified in a SARS-CoV-2-infected inflammatory cell model. In addition, glycyrrhisoflavone and licoisoflavone A also displayed strong inhibitory activities against cAMP-specific 3',5'-cyclic phosphodiesterase 4 (PDE4). Crystal structures of PDE4 in complex with glycyrrhisoflavone or licoisoflavone A were determined at resolutions of 1.54 Å and 1.65 Å, respectively, and both compounds bind in the active site of PDE4 with similar interactions. These findings will greatly stimulate the study of TCMT-NDRD against COVID-19.

Pharmacological characterization of the small molecule 03A10 as an inhibitor of α-synuclein aggregation for Parkinson's disease treatment.

Aggregation of α-synuclein, a component of Lewy bodies (LBs) or Lewy neurites in Parkinson's disease (PD), is strongly linked with disease development, making it an attractive therapeutic target. Inhibiting aggregation can slow or prevent the neurodegenerative process. However, the bottleneck towards achieving this goal is the lack of such inhibitors. In the current study, we established a high-throughput screening platform to identify candidate compounds for preventing the aggregation of α-synuclein among the natural products in our in-house compound library. We found that a small molecule, 03A10, i.e., (+)-desdimethylpinoresinol, which is present in the fruits of Vernicia fordii (Euphorbiaceae), modulated aggregated α-synuclein, but not monomeric α-synuclein, to prevent further elongation of α-synuclein fibrils. In α-synuclein-overexpressing cell lines, 03A10 (10 µM) efficiently prevented α-synuclein aggregation and markedly ameliorated the cellular toxicity of α-synuclein fibril seeds. In the MPTP/probenecid (MPTP/p) mouse model, oral administration of 03A10 (0.3 mg· kg-1 ·d-1, 1 mg ·kg-1 ·d-1, for 35 days) significantly alleviated behavioral deficits, tyrosine hydroxylase (TH) neuron degeneration and p-α-synuclein aggregation in the substantia nigra (SN). As the Braak hypothesis postulates that the prevailing site of early PD pathology is the gastrointestinal tract, we inoculated α-synuclein preformed fibrils (PFFs) into the mouse colon. We demonstrated that α-synuclein PFF inoculation promoted α-synuclein pathology and neuroinflammation in the gut and brain; oral administration of 03A10 (5 mg· kg-1 ·d-1, for 4 months) significantly attenuated olfactory deficits, α-synuclein accumulation and neuroinflammation in the olfactory bulb and SN. We conclude that 03A10 might be a promising drug candidate for the treatment of PD. 03A10 might be a novel drug candidate for PD treatment, as it inhibits α-synuclein aggregation by modulating aggregated α-synuclein rather than monomeric α-synuclein to prevent further elongation of α-synuclein fibrils and prevent α-synuclein toxicity in vitro, in an MPTP/p mouse model, and PFF-inoculated mice.

Gui Shao Tea Extracts Inhibit Gastric Cancer Growth in Vitro and in Vivo and Prolong Survival in Nude Mice.

BACKGROUND: Gui Shao Tea (GST), a long-aged tea with a Chinese herbal aroma, can treat many stubborn and malignant diseases, according to traditional Chinese medicine. This research aimed to discover and define GST, study the anti-gastric cancer effects of GST extracts and preliminarily elucidate the mechanism of action in the PI3K/Akt signaling pathway and the gut microbiota. METHODS: GST was analyzed by GC/MS and HPLC. Cell proliferation, the cell cycle and apoptosis were evaluated by a CCK8 assay and flow cytometry. The effects of GST extracts on tumor inhibition and survival time were explored by a gastric cancer xenograft model in nude mice. The PI3K/Akt signaling pathway was assessed by western blotting and immunohistochemistry. Gut microbiota detection and fecal microbiota transplantation were performed to examine whether the tumor inhibition observed in mice was related to gut microbiota changes. RESULTS: The ingredients in GST, mostly terpenes and their derivatives, were novel and more concentrated than those in tea made from the branches and leaves of the same plant species, Camellia sinensis, picked and produced the same year, while the levels of polyphenols and alkaloids were significantly reduced. In BGC-823, MGC-803, and SGC-7901 gastric cancer cells, GST extracts significantly inhibited proliferation (p = 0.037), induced G0/G1 arrest (p < 0.001) and promoted early apoptosis (p = 0.041). In mice, gastric tumor growth was significantly inhibited in both the high-dose (HTF) and middle-dose (MTF) GST-fed groups. The inhibition rate in the HTF group was 33.77% on Day 14 (p = 0.042), and that in the MTF group was 55.21% on Day 14 (p = 0.002) and 61.6% on Day 28 (p = 0.008). The survival time of MTF group mice was significantly prolonged by 22.2% (p = 0.013). GST extracts inhibited the PI3K/AKT signaling pathway in gastric cancer cells (p = 0.016) and tissues (p = 0.029), downregulated the protein p-Rb and further downregulated E2F1, thereby affecting the cell cycle and proliferation. GST extracts altered the gut microbiota in mice, but these alterations alone were insufficient to inhibit gastric cancer growth. CONCLUSIONS: We confirmed the anti-gastric cancer effects of GST extracts, which might provide new approaches and methods for research and development of gastric cancer drugs.

Glycosides from Buddleja officinalis with their protective effects on photoreceptor cells in light-damaged mouse retinas.

A new phenylethanoid, hebitol IV (1), along with fifteen known glycosides (2-16), were isolated from water extract of the flower buds of Buddleja officinalis. Their structures were elucidated on the basis of 1 D-NMR, 2 D-NMR and MS data. Molecular docking showed the potential activities of the natural products against VEGFR-2. Bioassay results revealed that the compounds 10 and 14 exhibited strong inhibitory activity against VEGFR-2 with IC50 values of 0.51 and 0.32 µM, respectively. Moreover, the potential retinal protective effects of 10 and 14 were then investigated in the mouse model featuring bright light-induced retinal degeneration. The results demonstrated remarkable photoreceptor protective activities of 10 and 14 in vivo.

DCZ0014, a novel compound in the therapy of diffuse large B-cell lymphoma via the B cell receptor signaling pathway.

Diffuse large B cell lymphoma (DLBCL) is a clinical and genetically heterogeneous lymphoid malignancy. Although R-CHOP (rituximab plus cyclophosphamide, vincristine, doxorubicin, and prednisone) treatment can improve the survival rate of patients with DLBCL, more than 30% of patients exhibit treatment failure, relapse, or refractory disease. Therefore, novel drugs or targeted therapies are needed to improve the survival of patients with DLBCL. The compound DCZ0014 is a novel chemical similar to berberine. In this study, we found that DCZ0014 significantly inhibited the proliferation and activity of DLBCL cells, and induced cell apoptosis. Following treatment with DCZ0014, DLBCL cells accumulated in G0/G1-phase of the cell cycle and showed decreased mitochondrial membrane potential. Additionally, DCZ0014 inhibited DNA synthesis, enhanced DNA damage in DLBCL cells, as well as inhibited Lyn/Syk in B cell receptor signaling pathway. Further experiments demonstrated that DCZ0014 did not significantly affect peripheral blood mononuclear cells. Tumor xenograft model showed that DCZ0014 not only inhibited tumor growth but also extended the survival time of mice. Thus, DCZ0014 showed potential for clinical application in the treatment of patients with DLBCL.

Pharmacophore-Based Virtual Screening Toward the Discovery of Novel Anti-echinococcal Compounds.

Echinococcosis is a serious helminthic zoonosis with a great impact on human health and livestock husbandry. However, the clinically used drugs (benzimidazoles) have a low cure rate, so alternative drugs are urgently needed. Currently, drug screenings for echinococcosis are mainly phenotype-based, and the efficiency of identifying active compounds is very low. With a pharmacophore model generated from the structures of active amino alcohols, we performed a virtual screening to discover novel compounds with anti-echinococcal activity. Sixty-two compounds from the virtual screening were tested on Echinococcus multilocularis protoscoleces, and 10 of these compounds were found to be active. After further evaluation of their cytotoxicity, S6 was selected along with two active amino alcohols for in vivo pharmacodynamic and pharmacokinetic studies. At the two tested doses (50 and 25 mg/kg), S6 inhibited the growth of E. multilocularis in mice (14.43 and 9.53%), but no significant difference between the treatment groups and control group was observed. Treatment with BTB4 and HT3 was shown to be ineffective. During the 28 days of treatment, the death of mice in the mebendazole, HT3, and BTB4 groups indicated their toxicity. The plasma concentration of S6 administered by both methods was very low, with the Cmax being only 1 ng/ml after oral administration and below the detection limit after intramuscular administration. In addition, the plasma concentrations of BTB4 and HT3 in vitro did not reach high enough levels to kill the parasites. The toxicities of these two amino alcohols indicated that they are not suitable for further development as anti-echinococcal drugs. However, further attempts should be made to increase the bioavailability of S6 and modify its structure. In this study, we demonstrate that pharmacophore-based virtual screenings with high drug identification efficiency could be used to find novel drugs for treating echinococcosis.

Dihydrocelastrol exerts potent antitumor activity in mantle cell lymphoma cells via dual inhibition of mTORC1 and mTORC2.

Mantle cell lymphoma (MCL) is a distinct and highly aggressive subtype of B-cell non-Hodgkin lymphoma. Dihydrocelastrol (DHCE) is a dihydro-analog of celastrol, which is isolated from the traditional Chinese medicinal plant Tripterygium wilfordii. The present study aimed to investigate the effects of DHCE treatment on MCL cells, and to determine the mechanism underlying its potent antitumor activity in vitro and in vivo using the Cell Counting kit-8 assay, clonogenic assay, apoptosis assay, cell cycle analysis, immunofluorescence staining, western blotting and tumor xenograft models. The results demonstrated that DHCE treatment exerted minimal cytotoxic effects on normal cells, but markedly suppressed MCL cell proliferation by inducing G0/G1 phase cell cycle arrest, and inhibited MCL cell viability by stimulating apoptosis via extrinsic and intrinsic pathways. In addition, the results revealed that DHCE suppressed cell growth and proliferation by inhibiting mammalian target of rapamycin complex (mTORC)1-mediated phosphorylation of ribosomal protein S6 kinase and eukaryotic initiation factor 4E binding protein. Simultaneously, DHCE induced apoptosis and inhibited cell survival by suppressing mTORC2-mediated phosphorylation of protein kinase B and nuclear factor-κB activity. In addition to in vitro findings, DHCE treatment reduced the MCL tumor burden in a xenograft mouse model, without indications of toxicity. Furthermore, combined treatment with DHCE and bortezomib, a proteasome inhibitor, induced a synergistic cytotoxic effect on MCL cells. These findings indicated that DHCE may have the potential to serve as a novel therapeutic agent for the treatment of MCL through dually inhibiting mTORC1 and mTORC2.

Combined Virtual Screening and Substructure Search for Discovery of Novel FABP4 Inhibitors.

Fatty acid-binding protein 4 (FABP4, AFABP) is a potential drug target for diabetes and atherosclerosis. In this study, a series of novel FABP4 inhibitors were discovered through combining virtual screening and substructure search. Seventeen compounds exhibited FABP4 inhibitory activities with IC50 < 10 µM, among which 11 compounds showed high selectivity against FABP3. The best compound 36b displayed an IC50 value of 1.5 µM. Molecular docking and point mutation studies revealed that Gln95, Arg126, and Tyr128 play key roles for these compounds binding with FABP4. Interestingly, Gln95 seems to be essential for conformation stability of FABP4. The new scaffolds of these compounds and their interaction mechanisms binding with FABP4 should provide an important clue for the further development of novel FABP4 inhibitors.

Dihydrocelastrol inhibits multiple myeloma cell proliferation and promotes apoptosis through ERK1/2 and IL-6/STAT3 pathways in vitro and in vivo.

Multiple myeloma (MM) is the second most frequent malignant hematological disease. Dihydrocelastrol (DHCE) is synthesized by hydrogenated celastrol, a treterpene isolated from Chinese medicinal plant Tripterygium regelii. In this study, we first reported the anti-tumor activity of DHCE on MM cells. We found that DHCE could inhibit cell proliferation and promote apoptosis through caspase-dependent way in vitro. In addition, DHCE could inactivate the expression of interleukin (IL)-6 and downregulate the phosphorylation of extracellular regulated protein kinases (ERK1/2) and the signal transducer and activator of transcription 3 (STAT3) in MM. It also retained its activity against MM cell lines in the presence of IL-6. Furthermore, treatment of MM cells with DHCE resulted in an accumulation of cells in G0/G1 phase of the cell cycle. Notably, DHCE reduced the expression of cyclin D1 and cyclin-dependent kinases 4 and 6 in MM cell lines. Additionally, its efficacy toward the MM cell lines could be enhanced in combination with the histone deacetylase inhibitor panobinostat (LBH589), which implied the possibility of the combination treatment of DHCE and LBH589 as a potential therapeutic strategy in MM. In addition, treatment of NCI-H929 tumor-bearing nude mice with DHCE (10 mg/kg/d, i.p., 1-14 days) resulted in 73% inhibition of the tumor growth in vivo. Taken together, the results of our present study indicated that DHCE could inhibit cellular proliferation and induce cell apoptosis in myeloma cells mediated through different mechanisms, possibly through inhibiting the IL-6/STAT3 and ERK1/2 pathways. And it may provide a new therapeutic option for MM patients.

Repositioning organohalogen drugs: a case study for identification of potent B-Raf V600E inhibitors via docking and bioassay.

Drug repositioning has been attracting increasingly attention for its advantages of reducing costs and risks. Statistics showed that around one quarter of the marketed drugs are organohalogens. However, no study has been reported, to the best of our knowledge, to aim at efficiently repositioning organohalogen drugs, which may be attributed to the lack of accurate halogen bonding scoring function. Here, we present a study to show that two organohalogen drugs were successfully repositioned as potent B-Raf V600E inhibitors via molecular docking with halogen bonding scoring function, namely D(3)DOCKxb developed in our lab, and bioassay. After virtual screening by D(3)DOCKxb against the database CMC (Comprehensive Medicinal Chemistry), 3 organohalogen drugs that were predicted to form strong halogen bonding with B-Raf V600E were purchased and tested with ELISA-based assay. In the end, 2 of them, rafoxanide and closantel, were identified as potent inhibitors with IC50 values of 0.07 µM and 1.90 µM, respectively, which are comparable to that of vemurafenib (IC50: 0.17 µM), a marketed drug targeting B-Raf V600E. Single point mutagenesis experiments confirmed the conformations predicted by D(3)DOCKxb. And comparison experiment revealed that halogen bonding scoring function is essential for repositioning those drugs with heavy halogen atoms in their molecular structures.

Inhibitory Effects of (2'R)-2',3'-dihydro-2'-(1-hydroxy-1-methylethyl)-2,6'-bibenzofuran-6,4'-diol on Mushroom Tyrosinase and Melanogenesis in B16-F10 Melanoma Cells.

(2'R)-2',3'-Dihydro-2'-(1-hydroxy-1-methylethyl)-2,6'-bibenzofuran-6,4'-diol (DHMB) is a natural compound extracted from Morus notabilis. It was found that DHMB acts as a competitive inhibitor against mushroom tyrosinase with a Ki value of 14.77 µM. Docking results further indicated that it could form strong interactions with one copper ion with a distance of 2.7 Å, suggesting the mechanism of inhibition might be due to chelating copper ions in the active site. Furthermore, melanin production in B16-F10 murine melanoma cells was significantly inhibited by DHMB in a concentration-dependent manner without cytotoxicity. The results of western blotting also showed that DHMB decreased 3-isobuty-1-methxlzanthine-induced mature tyrosinase expression. Taken together, these findings indicated that DHMB may be a new promising pigmentation-altering agent for agriculture, cosmetic, and therapeutic applications.

[Study on Rapid Micropropagation in Vitro Technique of Guangfeng Medicinal Yam (Dioscorea opposita) Plantlets].

OBJECTIVE: In order to provide methodology reference for virus-free and germplasm conservation of Guangfeng medicinal yam (Dioscorea opposita) plantlets, rapid micropropagation in vitro technique of Guangfeng medicinal yam plantlets was studied. METHODS: Using the method of plant tissue culture, single factor test and flow-cytometry, the basic procedure of Guangfeng medicinal yam tissue culture was established and the DNA content of Guangfeng medicinal yam plantlets and its potted seedlings was detected. RESULTS: The best disinfection procedure of stems with a bud of Guangfeng medicinal yam was washed with sterile water for three times after sterilized with 70% alcohol for 20 - 30 s and then washed with sterile water for three times again after sterilized with 0.1% mercuric chloride for 10 - 12 min; The best explants of stems with a bud of Guangfeng medicinal yam was slightly woody and more mature stems witha bud; The best proliferation culture medium of stems with a bud of Guangfeng medicinal yam was MS + 6-BA 2.0 mg/L + NAA 0.1 mg/L; The best rooting culture medium of stems with a bud of Guangfeng medicinal yam was MS + NAA 0.5 mg/L; The best culture method of Guangfeng medicinal yam plantlets was liquid culture; The best transplanting matrix of Guangfeng medicinal yam plantlets was the mixture of paddy clay and fine sand (1: 2) or the mixture of perlite and vermiculite (1: 2); The DNA content between Guangfeng medicinal yam plantlets and its potted seedlings had no significant difference. CONCLUSION: A fast and efficient micropropagation in vitro technological system of stems with a bud of Guangfeng medicinal yam is established, and the flow cytometry detect results also show the genetic stability of Guangfeng medicinal yam plantlets, whose results provide the technical and theoretical basis for the large-scale production of Guangfeng medicinal yam plantlets.

[Results of low-dose computed tomography (LDCT) screening for early lung cancer: prevalence in 4 690 asymptomatic participants].

OBJECTIVE: To report the results of low-dose computed tomography (LDCT) screening for early lung cancer in 4 690 asymptomatic participants at the Cancer Hospital, Chinese Academy of Medical Sciences between July 2007 and June 2012. METHODS: After informed consent and questionnaire forms were obtained, 4 690 asymptomatic participants ≥ 40 years underwent chest low dose spiral CT scanning. According to the National Comprehensive Cancer Network (NCCN) guideline for lung cancer screening (version 1.1, 2012), all participants were assigned to three groups, namely high-risk, moderate-risk and low-risk groups. In terms of gender, smoking history and second-hand tobacco smoking exposure history, two other groups named male and female never-smoker groups who were exposed to second-hand tobacco smoking were designated. The positive results were identified as at least one solid or part-solid nodule measuring ≥ 5 mm, or non-solid nodule ≥ 8 mm in diameter. LDCT scanning protocol, criteria of management according to the size and consistency of pulmonary nodules were compliant with the International Early Lung Cancer Active Program (I-ELCAP). TNM staging of all lung cancers were based on the clinical evidence and pathological findings. RESULTS: In various risk status group of the participants, the percentage of positive results of baseline CT were 27.0% (86/319), 19.3% (199/1 029) and 11.3% (377/3 342), respectively. A total of 26 participants (27 lesions) were diagnosed as lung cancer (11 in men, 15 in women). The detection rate of lung cancer was 0.6% (26/4 690). Besides a SCLC (limited-disease, LD), 25 cases (76.0%) were stage I including 24 NSCLC and one cacinoid on baseline LDCT and the surgical resection rate was 88.5% (23/26). The diameter of resected cancers was 6.9-29.5 mm (median, 16.3 mm). For female never smokers aged 40 years or older who were exposed to second-hand smoking, the detection rate of lung cancer was higher than that of the high-risk and male never smokers who were exposed to second-hand smoking (1.4% vs. 0.9%, 0.4%). CONCLUSIONS: The results indicate that LDCT can detect small lung cancers and most of the cancers are detected at an early stage. Emphasis should be placed on the non-smoking female individuals who are exposed to second-hand smoking in China.

Dodoviscin a inhibits melanogenesis in mouse b16-f10 melanoma cells.

Nowadays, abnormal hyperpigmentation in human skin such as melasma, freckles, and chloasma has become a serious esthetic problem. Cutaneous depigmenting agents could be used to treat these hyperpigmentation-associated dieseases. Dodoviscin A is a natural product isolated from the aerial parts of Dodonaea viscosa. In the present study, we evaluated the effect of dodoviscin A on melanin production in B16-F10 melanoma cells for the first time. We found that dodoviscin A inhibited melanin biosynthesis induced by 3-isobutyl-1-methylxanthine and PD98059 significantly, and there was no obvious effect on the viability of dodoviscin A-treated B16-F10 cells. Meanwhile, dodoviscin A could suppress the activity of mushroom tyrosinase in the cell-free assay system and also decrease 3-isobutyl-1-methylxanthine-induced tyrosinase activity and expression of mature tyrosinase protein in B16-F10 cells. Western blotting analysis showed that dodoviscin A inhibited 3-isobutyl-1-methylxanthine and forskolin-induced phosphorylation of the cAMP response element binding protein in B16-F10 cells. These results indicate that dodoviscin A may be a new promising pigmentation-altering agent for cosmetic and therapeutic applications.