Injectable Hydrogels Based on Hyaluronic Acid and Gelatin Combined with Salvianolic Acid B and Vascular Endothelial Growth Factor for Treatment of Traumatic Brain Injury in Mice.

Traumatic brain injury (TBI) leads to structural damage in the brain, and is one of the major causes of disability and death in the world. Herein, we developed a composite injectable hydrogel (HA/Gel) composed of hyaluronic acid (HA) and gelatin (Gel), loaded with vascular endothelial growth factor (VEGF) and salvianolic acid B (SAB) for treatment of TBI. The HA/Gel hydrogels were formed by the coupling of phenol-rich tyramine-modified HA (HA-TA) and tyramine-modified Gel (Gel-TA) catalyzed by horseradish peroxidase (HRP) in the presence of hydrogen peroxide (H2O2). SEM results showed that HA/Gel hydrogel had a porous structure. Rheological test results showed that the hydrogel possessed appropriate rheological properties, and UV spectrophotometry results showed that the hydrogel exhibited excellent SAB release performance. The results of LIVE/DEAD staining, CCK-8 and Phalloidin/DAPI fluorescence staining showed that the HA/Gel hydrogel possessed good cell biocompatibility. Moreover, the hydrogels loaded with SAB and VEGF (HA/Gel/SAB/VEGF) could effectively promote the proliferation of bone marrow mesenchymal stem cells (BMSCs). In addition, the results of H&E staining, CD31 and α-SMA immunofluorescence staining showed that the HA/Gel/SAB/VEGF hydrogel possessed good in vivo biocompatibility and pro-angiogenic ability. Furthermore, immunohistochemical results showed that the injection of HA/Gel/SAB/VEGF hydrogel to the injury site could effectively reduce the volume of defective tissues in traumatic brain injured mice. Our results suggest that the injection of HA/Gel hydrogel loaded with SAB and VEGF might provide a new approach for therapeutic brain tissue repair after traumatic brain injury.

The histamine H4 receptor antagonist 1-[(5-chloro-2,3-dihydro-1-benzofuran-2-yl)methyl]-4-methyl-piperazine(LINS01007) prevents the development of DSS-induced colitis in mice.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with growing incidence worldwide. Our group reported the compound 5-choro-1-[(2,3-dihydro-1-benzofuran-2-yl)methyl]piperazine (LINS01007) as H4R antagonist (pKi 6.2) and therefore the effects and pharmacological efficacy on a DSS-induced mice model of UC were assessed in this work. Experimental acute colitis was induced in male BALB/c mice (n = 5-10) by administering 3 % DSS in the drinking water for six days. The test compound LINS01007 was administered daily i.p. (5 mg/kg) and compared to control group without treatment. Body weight, water and food consumption, and the presence of fecal blood were monitored during 7-day treatment period. The levels of inflammatory markers (PGE2, COX-2, IL-6, NF-κB and STAT3) were also analyzed. Animals subjected to the acute colitis protocol showed a reduction in water and food intake from the fourth day (p < 0.05) and these events were prevented by LINS01007. Histological signs of edema, hyperplasia and disorganized intestinal crypts, as well as neutrophilic infiltrations, were found in control mice while these findings were significantly reduced in animals treated with LINS01007. Significant reductions in the levels of PGE2, COX-2, IL-6, NF-κB and STAT3 were observed in the serum and tissue of treated animals. The results demonstrated the significant effects of LINS01007 against DSS-induced colitis, highlighting the potential of H4R antagonism as promising treatment for this condition.

Fruquintinib as new treatment option in metastatic colorectal cancer patients: is there an optimal sequence?

INTRODUCTION: Available treatments for colorectal cancer are limited. However, in the last few years several advances and new treatment options became available and expanded the continuum of care in metastatic colorectal cancer (mCRC). AREAS COVERED: Fruquintinib, a tyrosine kinase inhibitor, has been shown to be effective in heavily pretreated mCRC progressing to trifluridine-tipiracil (FTD/TPI) or regorafenib or both. Preclinical studies have shown that fruquintinib inhibits with high selectivity VEGFR 1-2-3, leading to a blockade in angiogenesis process, but also acts, with weak inhibition, on RET, FGFR-1, and c-kit kinases. Fruquintinib demonstrated good efficacy and tolerance in chemorefractory mCRC in two phase III trial: FRESCO and FRESCO 2. These results led to FDA approval of fruquintinib for pretreated mCRC patients who received prior fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy. EXPERT OPINION: Fruquintinib is a valid therapeutic option for heavily pretreated mCRC patients. However, an optimal sequence of treatments is yet to be defined. In this review, we propose an algorithm for later lines of treatment to integrate fruquintinib as a standard of care together with the new therapeutic combinations that recently showed clinical benefit for chemorefractory mCRC, in both molecularly selected (e.g. KRASG12C or HER2 amplification) and in non-oncogenic driven patients.

Synthesis and Neuroprotective Evaluation of Substituted Indanone/Benzofuranone and Piperidine Hybrids.

Based on the neuroprotection of butylphthalide and donepezil, a series of indanone/benzofuranone and piperidine hybrids were designed and synthesized for assessment of their neuroprotective activities, aiming to enhance the bioavailability and therapeutic efficacy of natural phthalide analogues. Within this study, it was observed that most indanone derivatives bearing 1-methylpiperidine in the tail segment demonstrated superior neuroprotective effects on the oxygen glucose deprivation/reperfusion (OGD/R)-induced rat primary neuronal cell injury model in vitro compared to benzofuranone compounds. Among the synthesized compounds, 11 (4, 14, 15, 22, 26, 35, 36, 37, 48, 49, and 52) displayed robust cell viabilities in the OGD/R model, along with favorable blood-brain barrier permeability as confirmed by the parallel artificial membrane permeability assay. Notably, compound 4 showed significant neuronal cell viabilities within the concentration range of 3.125 to 100 µM, without inducing cytotoxicity. Further results from in vivo middle cerebral artery occlusion/R experiments revealed that 4 effectively ameliorated ischemia-reperfusion injury, reducing the infarct volume to 18.45% at a dose of 40 mg/kg. This outcome suggested a superior neuroprotective effect compared to edaravone at 20 mg/kg, further highlighting the potential therapeutic efficacy of compound 4 in addressing neurological disorders.

Supplementation of Silymarin Alone or in Combination with Salvianolic Acids B and Puerarin Regulates Gut Microbiota and Its Metabolism to Improve High-Fat Diet-Induced NAFLD in Mice.

Silymarin, salvianolic acids B, and puerarin were considered healthy food agents with tremendous potential to ameliorate non-alcoholic fatty liver disease (NAFLD). However, the mechanisms by which they interact with gut microbiota to exert benefits are largely unknown. After 8 weeks of NAFLD modeling, C57BL/6J mice were randomly divided into five groups and fed a normal diet, high-fat diet (HFD), or HFD supplemented with a medium or high dose of Silybum marianum extract contained silymarin or polyherbal extract contained silymarin, salvianolic acids B, and puerarin for 16 weeks, respectively. The untargeted metabolomics and 16S rRNA sequencing were used for molecular mechanisms exploration. The intervention of silymarin and polyherbal extract significantly improved liver steatosis and recovered liver function in the mice, accompanied by an increase in probiotics like Akkermansia and Blautia, and suppressed Clostridium, which related to changes in the bile acids profile in feces and serum. Fecal microbiome transplantation confirmed that this alteration of microbiota and its metabolites were responsible for the improvement in NAFLD. The present study substantiated that alterations of the gut microbiota upon silymarin and polyherbal extract intervention have beneficial effects on HFD-induced hepatic steatosis and suggested the pivotal role of gut microbiota and its metabolites in the amelioration of NAFLD.

Design, Synthesis, Antibacterial Activity, and Mechanisms of Novel Benzofuran Derivatives Containing Disulfide Moieties.

The unsatisfactory effects of conventional bactericides and antimicrobial resistance have increased the challenges in managing plant diseases caused by bacterial pests. Here, we report the successful design and synthesis of benzofuran derivatives using benzofuran as the core skeleton and splicing the disulfide moieties commonly seen in natural substances with antibacterial properties. Most of our developed benzofurans displayed remarkable antibacterial activities to frequently encountered pathogens, including Xanthomonas oryzae pv oryzae (Xoo), Xanthomonas oryzae pv oryzicola (Xoc), and Xanthomonas axonopodis pv citri (Xac). With the assistance of the three-dimensional quantitative constitutive relationship (3D-QSAR) model, the optimal compound V40 was obtained, which has better in vitro antibacterial activity with EC50 values of 0.28, 0.56, and 10.43 µg/mL against Xoo, Xoc, and Xac, respectively, than those of positive control, TC (66.41, 78.49, and 120.36 µg/mL) and allicin (8.40, 28.22, and 88.04 µg/mL). Combining the results of proteomic analysis and enzyme activity assay allows the antibacterial mechanism of V40 to be preliminarily revealed, suggesting its potential as a versatile bactericide in combating bacterial pests in the future.

α-Glucosidase Inhibitory Components from Garcinia pedunculata Fruits.

From Garcinia pedunculata Roxb. fruits, two undescribed aromatic compounds including a benzofuran and a depsidone derivative, and a new natural product, together with four known compounds were isolated. Through the analysis of spectroscopic data, high resolution mass spectrum and calculated nuclear magnetic resonance, their structures were determined. The α-glucosidase inhibitory activity of the isolates was evaluated. And compound 3 exhibited a moderate inhibitory effect on α-glucosidase. The molecular docking of compound 3 was performed to elucidate the interaction with α-glucosidase.

Metabolism, toxicity and management of fruquintinib: a novel drug for metastatic colorectal cancer.

INTRODUCTION: Colorectal cancer (CRC) is the third most diagnosed cancer globally and despite therapeutic strides, the prognosis for patients with metastatic disease (mCRC) remains poor. Fruquintinib is an oral vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor (TKI) targeting VEGFR -1, -2, and -3, and has recently received approval by the U.S. Food and Drug Administration for treatment of mCRC refractory to standard chemotherapy, anti-VEGF therapy, and anti-epidermal growth factor receptor (EGFR) therapy. AREAS COVERED: This article provides an overview of the pre-clinical data, pharmacokinetics, clinical efficacy, and safety profile of fruquintinib, as well as the management of clinical toxicities associated with fruquintinib. EXPERT OPINION: Fruquintinib is a valuable additional treatment option for patients with refractory mCRC. The pivotal role of vigilant toxicity management cannot be understated. While fruquintinib offers a convenient and overall, well-tolerated treatment option, ongoing research is essential to determine its efficacy in different patient subsets, evaluate it in combination with chemotherapy and immunotherapy, and determine its role in earlier lines of therapy.

Moracin D suppresses cell growth and induces apoptosis via targeting the XIAP/PARP1 axis in pancreatic cancer.

BACKGROUND: Pancreatic cancer, a tumor with a high metastasis rate and poor prognosis, is among the deadliest human malignancies. Investigating effective drugs for their treatment is imperative. Moracin D, a natural benzofuran compound isolated from Morus alba L., shows anti-inflammation and anti-breast cancer properties and is effective against Alzheimer's disease. However, the effect and mechanism of Moracin D action in pancreatic cancer remain obscure. PURPOSE: To investigate the function and molecular mechanism of Moracin D action in repressing the malignant progression of pancreatic cancer. METHODS: Pancreatic cancer cells were treated with Moracin D, and cell proliferation was evaluated by cell counting kit-8 (CCK-8) and immunofluorescence assays. The clonogenicity of pancreatic cancer cells was assessed based on plate colony formation and soft agar assay. Flow cytometry was used to detect cell apoptosis. The expression of proteins related to the apoptosis pathway was determined by Western blot analysis. Moracin D and XIAP were subjected to docking by auto-dock molecular docking analysis. Ubiquitination levels of XIAP and the interaction of XIAP and PARP1 were assessed by co-immunoprecipitation analysis. Moracin D's effects on tumorigenicity were assessed by a tumor xenograft assay. RESULTS: Moracin D inhibited cell proliferation, induced cell apoptosis, and regulated the protein expression of molecules involved in caspase-dependent apoptosis pathways. Moracin D suppressed clonogenicity and tumorigenesis of pancreatic cancer cells. Mechanistically, XIAP could interact with PARP1 and stabilize PARP1 by controlling its ubiquitination levels. Moracin D diminished the stability of XIAP and decreased the expression of XIAP by promoting proteasome-dependent XIAP degradation, further blocking the XIAP/PARP1 axis and repressing the progression of pancreatic cancer. Moracin D could dramatically improve the chemosensitivity of gemcitabine in pancreatic cancer cells. CONCLUSION: Moracin D repressed cell growth and tumorigenesis, induced cell apoptosis, and enhanced the chemosensitivity of gemcitabine through the XIAP/PARP1 axis in pancreatic cancer. Moracin D is a potential therapeutic agent or adjuvant for pancreatic cancer.

Molecular crosstalk between MUC1 and STAT3 influences the anti-proliferative effect of Napabucasin in epithelial cancers.

MUC1 is a transmembrane glycoprotein that is overexpressed and aberrantly glycosylated in epithelial cancers. The cytoplasmic tail of MUC1 (MUC1 CT) aids in tumorigenesis by upregulating the expression of multiple oncogenes. Signal transducer and activator of transcription 3 (STAT3) plays a crucial role in several cellular processes and is aberrantly activated in many cancers. In this study, we focus on recent evidence suggesting that STAT3 and MUC1 regulate each other's expression in cancer cells in an auto-inductive loop and found that their interaction plays a prominent role in mediating epithelial-to-mesenchymal transition (EMT) and drug resistance. The STAT3 inhibitor Napabucasin was in clinical trials but was discontinued due to futility. We found that higher expression of MUC1 increased the sensitivity of cancer cells to Napabucasin. Therefore, high-MUC1 tumors may have a better outcome to Napabucasin therapy. We report how MUC1 regulates STAT3 activity and provide a new perspective on repurposing the STAT3-inhibitor Napabucasin to improve clinical outcome of epithelial cancer treatment.

Improvement in non-24-h sleep-wake rhythm disorder in a sighted individual treated with a melatonin receptor agonist.

Non-24-hour sleep-wake rhythm disorder (N24SWD) typically presents in patients with visual impairments that disrupt the ability to entrain to the 24 hour solar cycle. We discuss a 43 year old sighted man who presented with periodic daytime hypersomnia and nighttime insomnia, occasionally leading to <3 hours of sleep per day. Previous polysomnography showed an apnea hypopnea index of 6.2 events per hour. A sleep log of 3 months showed irregular time of sleep onset, and an average of 3 hours of sleep per day. Wrist actigraphy confirmed N24SWD. A trial of tasimelteon 20 mg/day resulting in improved daytime hypersomnia (pre-Epworth Sleepiness Scale (ESS) = 21/24, post-ESS = 5/24; a score of > 10/24 is considered sleepy). Follow-up actigraphy showed marked resolution of phase delay with an average of five hours of sleep. The case demonstrates that tasimelteon is a possible treatment for N24SWD in sighted individuals.

Cytotoxic naphtho- and benzofurans from an endophytic fungus Epicoccum nigrum Ann-B-2 associated with Annona squamosa fruits.

Chemical exploration of the total extract derived from Epicoccum nigrum Ann-B-2, an endophyte associated with Annona squamosa fruits, afforded two new metabolites, epicoccofuran A (1) and flavimycin C (2), along with four known compounds namely, epicocconigrone A (3), epicoccolide B (4), epicoccone (5) and 4,5,6-trihydroxy-7-methyl-1,3-dihydroisobenzofuran (6). Structures of the isolated compounds were elucidated using extensive 1D and 2D NMR along with HR-ESI-MS. Flavimycin C (2) was isolated as an epimeric mixture of its two diastereomers 2a and 2b. The new compounds 1 and 2 displayed moderate activity against B. subtilis, whereas compounds (2, 3, 5, and 6) showed significant antiproliferative effects against a panel of seven different cancer cell lines with IC50 values ranging from 1.3 to 12 µM.

Morushalunin D, a tri-O-bridged Diels-Alder type adduct from Morus alba var. shalun root cultures and the related precursors.

Three Diels-Alder type adducts (1-3) along with their precursors, including one 2-arylbenzofuran (4) and one stilbene (5), were isolated from the MeOH extract of M. alba var. shalun root cultures. Among them, 1 is a new Diels-Alder type adduct named morushalunin D. The molecular structures of 1-5 were elucidated based on spectroscopic data and comparison with the literatures. Cytotoxic properties of compounds 1-5 were evaluated against murine leukemia P-388 cells. Morushalunin D (1), mulberrofuran T (2), sorocein A (3), moracin M (4), and oxyresveratrol (5) were active, significantly inhibiting the growth of P-388 cells with IC50 values of 0.5, 1.0, 0.6, 2.0, and 3.3 µg/ml, respectively.

Antineoplastic Activity of 9″-Lithospermic Acid Methyl Ester in Glioblastoma Cells.

To date, many potent compounds have been found which are derived from plants and herbs and possess anticancer properties due to their antioxidant effects. 9″-Lithospermic acid methyl ester is an effective natural compound derived from the Thymus thracicus Velen. It has been proven that this compound has substantial properties in different diseases, but its effects in cancer have not been thoroughly evaluated. The aim of this work was to study the effects of 9″-Lithospermic acid methyl ester (9″-methyl lithospermate) in U87 and T98 glioblastoma cell lines. Its effects on cellular viability were assessed via Trypan Blue and Crystal Violet stains, the cell cycle analysis through flow cytometry, and cell migration by employing the scratch wound healing assay. The results demonstrated that 9″-methyl lithospermate was able to inhibit cellular proliferation, induce cellular death, and inhibit cell migration. Furthermore, these results were intensified by the addition of temozolomide, the most prominent chemotherapeutic drug in glioblastoma tumors. Further studies are needed to reproduce these findings in animal models and investigate if 9″-lithospermic acid methyl ester represents a potential new therapeutic addition for gliomas.

Fourteen new 2-benzylbenzofuran glycosides with cardioprotective activity from Heterosmilax yunnanensis.

Fourteen new 2-benzylbenzofuran O-glycosides (1-13, 15) and one new key precursor, diarylacetone (14) were isolated from the roots of Heterosmilax yunnanensis Gagnep, which all have characteristic 2,3,4-O-trisubstituted benzyl. Their structures were elucidated by 1D and 2D NMR, HRESIMS, UV and IR. The isolated compounds were assessed for their cardioprotective activities and compounds 1, 3 and 6 could significantly improve cardiomyocytes viability. Moreover, the mechanistic study revealed that these three compounds could significantly decrease intracellular ROS levels and maintain mitochondrial homeostasis upon hypoxia inducement. Consequently, 1, 3 and 6 might serve as potential lead compounds to prevent myocardial ischemia.

Benzofuran Derivatives from Cortex Mori Radicis and Their Cholinesterase-Inhibitory Activity.

The phytochemical investigation of Cortex Mori Radicis led to the isolation and identification of a new prenylated benzofuranone (1) and four ring-opening derivatives (2-5) named albaphenol A-E, as well as nigranol A (6), together with ten 2-arylbenzofuran derivatives (7-16). The characterization of the structures of the new compounds and the structural revision of nigranol A (6) were conducted using the comprehensive analysis of spectroscopic data (1D/2D NMR, HRESIMS, CD, and XRD). Compounds 1-16 were tested for their inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Compounds 1 and 4 showed weak BChE-inhibitory activity (IC50 45.5 and 61.0 µM); six 2-arylbenzofuran derivatives showed more-potent BChE-inhibitory activity (IC50 2.5-32.8 µM) than the positive control galantamine (IC50 35.3 µM), while being inactive or weakly inhibitory toward AChE. Cathafuran C (14) exhibited the most potent and selective inhibitory activity against BChE in a competitive manner, with a Ki value of 1.7 µM. The structure-activity relationships of the benzofuran-type stilbenes were discussed. Furthermore, molecular docking and dynamic simulations were performed to clarify the interactions of the inhibitor-enzyme complex.

Aureusidin ameliorates 6-OHDA-induced neurotoxicity via activating Nrf2/HO-1 signaling pathway and preventing mitochondria-dependent apoptosis pathway in SH-SY5Y cells and Caenorhabditis elegans.

Movement disorder Parkinson's disease (PD) is the second most common neurodegenerative disease in the world after Alzheimer's disease, which severely affects the quality of patients' lives and imposes an increasingly heavy socioeconomic burden. Aureusidin is a kind of natural flavonoid compound with anti-inflammatory and anti-oxidant activities, while its pharmacological action and mechanism are rarely reported in PD. This study aimed to explore the neuroprotective effects and potential mechanisms of Aureusidin in PD. The present study demonstrated that Aureusidin protected SH-SY5Y cells from cell damage induced by 6-hydroxydopamine (6-OHDA) via inhibiting the mitochondria-dependent apoptosis and activating the Nrf2/HO-1 antioxidant signaling pathway. Additionally, Aureusidin diminished dopaminergic (DA) neuron degeneration induced by 6-OHDA and reduced the aggregation toxicity of α-synuclein (α-Syn) in Caenorhabditis elegans (C. elegans.) In conclusion, Aureusidin showed a neuroprotective effect in the 6-OHDA-induced PD model via activating Nrf2/HO-1 signaling pathway and prevented mitochondria-dependent apoptosis pathway, and these findings suggested that Aureusidin may be an effective drug for the treatment of PD.

Pharmacodynamic study of chitosan in combination with salvianolic acid B in the treatment of CC14 -induced liver fibrosis in mice.

Liver fibrosis is a chronic liver lesion caused by excessive deposition of the extracellular matrix after liver damage, resulting in fibrous scarring of liver tissue. The progression of liver fibrosis is partially influenced by the gut microbiota. Chitosan can play a therapeutic role in liver fibrosis by regulating the gut microbiota based on the 'gut-liver axis' theory. Salvianolic acid B can inhibit the development of liver fibrosis by inhibiting the activation of hepatic stellate cells and reducing the production of extracellular matrix. In this study, the therapeutic effect of chitosan in combination with salvianolic acid B on liver fibrosis was investigated in a mouse liver fibrosis model. The results showed that the combination of chitosan and salvianolic acid B was better than the drug alone, improving AST/ALT levels and reducing the expression of α-SAM, COL I, IL-6 and other related genes. It improved the structure of gut microbiota and increased the abundance of beneficial bacteria such as Lactobacillus. The above results could provide new ideas for the clinical treatment of liver fibrosis.

Suppression of lipopolysaccharide-induced COX-2 expression via p38MAPK, JNK, and C/EBPß phosphorylation inhibition by furomagydarin A, a benzofuran glycoside from Magydaris pastinacea.

The phytochemical investigation of the methanol extract of the seeds of Magydaris pastinacea afforded two undescribed benzofuran glycosides, furomagydarins A-B (1, 2), together with three known coumarins. The structures of the new isolates were elucidated after extensive 1D and 2D NMR experiments as well as HR MS. Compound 1 was able to inhibit the COX-2 expression in RAW264.7 macrophages exposed to lipopolysaccharide, a pro-inflammatory stimulus. RT-qPCR and luciferase reporter assays suggested that compound 1 reduces COX-2 expression at the transcriptional level. Further studies highlighted the capability of compound 1 to suppress the LPS-induced p38MAPK, JNK, and C/EBPß phosphorylation, leading to COX-2 down-regulation in RAW264.7 macrophages.

Novel Pyrazole-Based Benzofuran Derivatives as Anticancer Agents: Synthesis, Biological Evaluation, and Molecular Docking Investigations.

In this work, the design, synthesis, and mechanistic studies of novel pyrazole-based benzofuran derivatives 1-8 as anticancer agents were discussed. Cytotoxic potency of the title compounds was evaluated against the lung carcinoma A-549, human-derived colorectal adenocarcinoma HT-29, breast adenocarcinoma MCF-7 cells as well as mouse fibroblast 3T3-L1 cells using XTT assay. Anticancer mechanistic studies were carried out with flow cytometry. XTT results revealed that all compounds exhibited dose-dependent anti-proliferative activity against the tested cancer cells, and especially compound 2 showed the strongest anti-proliferative activity with an IC50 value of 7.31 µM and the highest selectivity (15.74) on MCF-7 cells. Flow cytometry results confirmed that the cytotoxic power of compound 2 on MCF-7 cells is closely related to mitochondrial membrane damage, caspase activation, and apoptosis orientation. Finally, molecular docking studies were applied to determine the interactions between compound 2 and caspase-3 via in-silico approaches. By molecular docking studies, free binding energy (ΔGBind), docking score, Glide score values as well as amino acid residues in the active binding site were determined. Consequently, these results constitute preliminary data for in vivo anticancer studies and have the potential as a chemotherapeutic agent.