SARS-CoV-2 main protease inhibition by compounds isolated from Luffa cylindrica using molecular docking.

In this study, chemical investigation of methanol extract of the air-dried fruits of Luffa cylindrica led to the identification of a new δ-valerolactone (1), along with sixteen known compounds (2-17). Their chemical structures including the absolute configuration were elucidated by extensive spectroscopic analysis and electronic circular dichroism analysis, as well as by comparison with those reported in the literature. For the first time in literature, we have examined the binding potential of the isolated compounds to highly conserved protein, Mpro of SARS-CoV-2 using the molecular docking technique. We found that the isolated saponins (14-17) bind to the substrate-binding pocket of SARS-CoV-2 Mpro with docking energy scores of -7.13, -7.29, -7.47, and -7.54 kcal.mol-1, respectively, along with binding abilities equivalent to an already claimed N3 protease inhibitor (-7.51 kcal.mol-1).

PTP1B Inhibitory and Anti-inflammatory Properties of Constituents from Eclipta prostrata L.

The white-flowered leaves of Eclipta prostrata L. together with leaves of Scoparia dulcis and Cynodon dactylon are mixedly boiled in water and given to diabetic patients resulting in the significant improvement in the management of diabetes. However, the active constituents from this plant for antidiabetic and anti-obesity properties are remaining unclear. Thus, this study was to discover anti-diabetes and anti-obesity activities through protein tyrosine phosphatases (PTP)1B inhibitory effects. We found that the fatty acids (23, 24) showed potent PTP1B inhibition with IC50 values of 2.14 and 3.21 µM, respectively. Triterpenoid-glycosides (12-15) also exhibited strong to moderate PTP1B inhibitory effects, with IC50 values ranging from 10.88 to 53.35 µM. Additionally, active compounds were investigated for their PTP1B inhibitory mechanism and docking analysis. On the other hand, the anti-inflammatory activity from our study revealed that compounds (1-4, 7, 8, 10) displayed the significant inhibition nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Especially, compound 9 showed the potent inhibitory effects in LPS-induced NO production on RAW264.7 cell. Therefore, further Western blot analysis was performed to identify the inhibitory expression including heme oxygenase-1 (HO-1) and inhibitor of kappaB (IκB) phosphorylation.

Tetra-aryl cyclobutane and stilbenes from the rhizomes of Rheum undulatum and their α-glucosidase inhibitory activity: Biological evaluation, kinetic analysis, and molecular docking simulation.

One achiral tetra-aryl cyclobutane [rheundulin A (1)] and three stilbene glycosides [rheundulins B-D (2-4)] were isolated from the methanol extract of Rheum undulatum L., along with eight known compounds (5-12). Structural determination of the new compounds (1-4) was accomplished using comprehensive spectroscopic methods. Compound 1 represents the first example of a dimeric stilbene linked via a cyclobutane ring from the Rheum genus. All isolates were screened for their inhibition against α-glucosidase. Among them, stilbene derivatives (5 and 6) showed strong inhibitory effects on α-glucosidase with IC50 values of 0.5 and 15.4 µM, respectively, which were significantly higher than that of the positive control, acarbose (IC50 = 126.8 µM). Rheundulin A (1) showed moderate α-glucosidase inhibition with an IC50 value of 80.1 µM. In addition, kinetic analysis and molecular docking simulation of the most active compound (5) with α-glucosidase were performed for the first time. Kinetic studies revealed that compound 5 competitively inhibited the active site of α-glucosidase (Ki = 0.40 µM), while 6 had a mixed-type inhibitory effect against α-glucosidase (Ki = 15.34 µM). Molecular docking simulations of 5 and 6 demonstrated negative-binding energies, indicating high proximity to the active site and tight binding to α-glucosidase enzyme.

Trichosanhemiketal A and B: Two 13,14-seco-13,14-epoxyporiferastanes from the root of Trichosanthes kirilowii Maxim.

Of the 32 Trichosanthes species in China, T. kirilowii Maxim. is the most renowned species used in traditional Chinese medicine and has diverse pharmacological properties. However, most of the phytochemical studies of T. kirilowii have focused on the fruits and seeds. In our investigation of the chemical constituents of T. kirilowii roots, two previously undescribed sterols [trichosanhemiketal A and B (1 and 2)], together with 13 known compounds, were isolated and their structures were elucidated. To the best of our knowledge, this represents the first isolation of compounds with a 13,14-seco-13,14-epoxyporiferastane (1-2) skeleton from the Cucurbitaceae family. The anti-inflammatory activity of the isolated compounds was determined through an analysis of their inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in macrophage RAW264.7 cells. Of the compounds, 4, 5, 6, and 8 showed significant inhibitory activities, with IC50 values of 8.5, 15.1, 25.4, and 28.5 µM, respectively. In addition, compound 4 inhibited inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 expression in a concentration-dependent manner.

Experimental and Computational Study to Reveal the Potential of Non-Polar Constituents from Hizikia fusiformis as Dual Protein Tyrosine Phosphatase 1B and α-Glucosidase Inhibitors.

Hizikia fusiformis (Harvey) Okamura is an edible marine alga that has been widely used in Korea, China, and Japan as a rich source of dietary fiber and essential minerals. In our previous study, we observed that the methanol extract of H. fusiformis and its non-polar fractions showed potent protein tyrosine phosphatase 1B (PTP1B) and α-glucosidase inhibition. Therefore, the aim of the present study was to identify the active ingredient in the methanol extract of H. fusiformis. We isolated a new glycerol fatty acid (13) and 20 known compounds including 9 fatty acids (1-3, 7-12), mixture of 24R and 24S-saringosterol (4), fucosterol (5), mixture of 24R,28R and 24S,28R-epoxy-24-ethylcholesterol (6), cedrusin (14), 1-(4-hydroxy-3-methoxyphenyl)-2-[2-hydroxy -4-(3-hydroxypropyl)phenoxy]-1,3-propanediol (15), benzyl alcohol alloside (16), madhusic acid A (17), glycyrrhizin (18), glycyrrhizin-6'-methyl ester (19), apo-9'-fucoxanthinone (20) and tyramine (21) from the non-polar fraction of H. fusiformis. New glycerol fatty acid 13 was identified as 2-(7'- (2″-hydroxy-3″-((5Z,8Z,11Z)-icosatrienoyloxy)propoxy)-7'-oxoheptanoyl)oxymethylpropenoic acid by spectroscopic analysis using NMR, IR, and HR-ESI-MS. We investigated the effect of the 21 isolated compounds and metabolites (22 and 23) of 18 against the inhibition of PTP1B and α-glucosidase enzymes. All fatty acids showed potent PTP1B inhibition at low concentrations. In particular, new compound 13 and fucosterol epoxide (6) showed noncompetitive inhibitory activity against PTP1B. Metabolites of glycyrrhizin, 22 and 23, exhibited competitive inhibition against PTP1B. These findings suggest that H. fusiformis, a widely consumed seafood, may be effective as a dietary supplement for the management of diabetes through the inhibition of PTP1B.

Lactones from the pericarps of Litsea japonica and their anti-inflammatory activities.

Five new lactones, litsenolide F1 (1), lisealactone H1 (10), lisealactone H2 (11), akolactone D (13), and akolactone E (14), along with thirteen known compounds were isolated from the pericarps of Litsea japonica (Thunb.) Jussieu. Their chemical structures were elucidated by extensive spectroscopic analyses, including 1D and 2D NMR, HRMS, and chemical methods. The isolated compounds were evaluated for their inhibitory effects on NO production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Among them, 2-alkylidene-3-hydroxy-4-methylbutanolide derivatives (compounds 1-9) exhibited the most potent activity, with IC50 values in the range of 2.9-12.8 µM. In additon, compounds 1, 3, 4, and 6 showed inhibition of iNOS and COX-2 expression in concentration-dependent manner. Compound 3 suppresses mRNA expression of iNOS, COX-2, IL-6, and TNF-α in LPS-stimulated RAW264.7 cells. Based on these evidence, the isolated lactones from L. japonica could be promissing candidates for the development of new anti-inflammatory agents.

Cholinesterase inhibitory alkaloids from the rhizomes of Coptis chinensis.

Coptis chinensis has been used as a medicinal herb in traditional oriental medicine. In this study, chemical investigation of a water extract of C. chinensis identified two new quaternary protoberberines (1, 2), a new tricyclic amide (3), together with five known compounds. Their chemical structures were elucidated by analysis with 1D and 2D NMR and high-resolution mass spectroscopy, as well as by comparison with those reported in the literature. Compounds 4, 5, and 7 showed potent inhibition against acetylcholinesterase (AChE) with IC50 values of 1.1, 5.6, and 12.9 µM, respectively. Compounds 2 and 4 showed inhibition of butyrylcholinesterase (BChE) with IC50 values of 11.5 and 27.8 µM, respectively. The kinetic activities were investigated to find out the type of enzyme inhibition involved. The types of AChE inhibition shown by compounds 5 and 7 were noncompetitive; BChE inhibition by compound 2 was also noncompetitive.

Lignan derivatives from Selaginella tamariscina and their nitric oxide inhibitory effects in LPS-stimulated RAW 264.7 cells.

The chemical characterization of Selaginella tamariscina leaves resulted in the isolation of five lignanoside derivatives (1-4 and 6) and one neolignan (5). These compounds include three new lignanosides, tamariscinosides D-F (1-3), and one liriodendrin (4) that were isolated for the first time from this plant, together with two known compounds, (2R,3S)-dihydro-2-(3,5-dimethoxy-4-hydroxyphenyl)-7-methoxy-5-acetyl-benzofuran (5) and moellenoside B (6). The chemical structures of these isolated compounds were determined using 1D and 2D NMR, MS, and CD spectroscopic data, and the results were compared to data previously reported in the literatures. These compounds were also evaluated in terms of their inhibition of NO production in lipopolysaccharide (LPS)-stimulated activity in the macrophage cell line RAW 264.7. Among them, compounds 1, 2, 5, and 6 exhibited a significant inhibition with IC50 values ranging from 32.3 to 55.8µM.

Cytotoxic and apoptosis-inducing activities against human lung cancer cell lines of cassaine diterpenoids from the bark of Erythrophleum fordii.

A phytochemical investigation into the bark of Erythrophleum fordii yielded four new compounds, two new cassaine diterpenoids (erythrofordin T and U, 1 and 2) and two new cassaine diterpenoid amines (erythroformine A and B, 6 and 7), as well as nine known compounds. We report for the first time the isolation of erythrofordin V (3) from a natural source and that of the remaining eight known diterpenoids (4-5, 8-13) from E. fordii. All structures were elucidated using spectroscopic analysis. Cytotoxic activity of the isolated compounds (1-13) was examined in vitro against three non-small cell lung cancer cell lines (A549, NCI-H1975, and NCI-H1229) using the MTT assay. Cassaine diterpene amines (6-10, 12, 13) exhibited potent cytotoxic activity against all three cell lines with IC50 values between 0.4µM and 5.9µM. Erythroformine B (7) significantly induced apoptosis in all three cancer cells in a concentration-dependent manner.

A new lignan and a new alkaloid, and α-glucosidase inhibitory compounds from the grains of Echinochloa utilis Ohwi & Yabuno.

A new lignan, utilisin (1), and a new alkaloid, echinoutilin (2), together with eleven known compounds 3-13 were isolated from the grains of Echinochloa utilis Ohwi & Yabuno. Their structures were identified through the analysis of spectroscopic data. The absolute configuration of 2 was determined by Mosher's method. These compounds were evaluated for α-glucosidase inhibitory activity. Among them, compounds 2, 3 and 6 exhibited considerable α-glucosidase inhibitory activity with IC50 values of 42.1±1.3, 58.9±3.7, and 40.9±1.1µM, respectively. The results indicate that the grains of E. utilis will be useful in the treatment of diabetes control agents.

PTP1B inhibitors from Selaginella tamariscina (Beauv.) Spring and their kinetic properties and molecular docking simulation.

Diabetes is one of the most popular worldwide diseases, regulated by the defects in insulin secretion, insulin action, or both. The overexpression of protein tyrosine phosphatase 1B (PTP1B) was found to down-regulate the insulin-receptor activation. PTP1B has been known as a strategy for the treatment of diabetes via the regulation of insulin signal transduction pathway. Herein, we investigated the PTP1B inhibitors isolated from natural sources. The chemical investigation of Selaginella tamariscina (Beauv.) Spring revealed seven unsaturated alkynyl phenols 1-7, four new selaginellins T-W 1-4 together with three known compounds 5-7 isolated from the aerial parts. The structures of the isolates were determined by spectroscopic techniques (1D/2D-NMR, MS, and CD). The inhibitory effects of these isolates on the PTP1B enzyme activity were investigated. Among them, compounds 2-7 significantly exhibited the inhibitory effects with the IC50 values ranging from 4.8 to 15.9µM. Compound 1 moderately displayed the inhibitory activity with an IC50 of 57.9µM. Furthermore, active compounds were discovered from their kinetic and molecular docking analysis. The results revealed that compounds 2 and 4-7 were mixed-competitive inhibitors, whereas compound 3 was a non-competitive inhibitor. This data confirm that these compounds exhibited potential inhibitory effect on the PTP1B enzyme activity.

Ellagitannin and flavonoid constituents from Agrimonia pilosa Ledeb. with their protein tyrosine phosphatase and acetylcholinesterase inhibitory activities.

A new ellagitannin, agritannin (1), a new flavone glycoside, agriflavone (2), and another flavone glycoside with spectroscopic data reported for the first time, kaempferol-3-O-[(S)-3-hydroxy-3-methylglutaryl (1→6)]-ß-d-glucoside (3), along with 16 known compounds were isolated from the aerial parts of Agrimonia pilosa Ledeb. These compounds were evaluated for PTP1B inhibitory activity. Among them, compounds 9 and 18 displayed potential inhibitory activity against PTP1B with IC50 values of 7.14±1.75 and 7.73±0.24µM, respectively. In addition, compound 1 showed significant inhibitory effect with an IC50 value of 17.03±0.09µM. Furthermore, these compounds were tested in AChE inhibitory assays. Most of them were found to have moderate inhibitory effects, with IC50 values ranging from 60.20±1.09 to 92.85±1.12µM. Except compounds 3, 8, and 18 were inactive.

Alkaloids from Piper nigrum Exhibit Antiinflammatory Activity via Activating the Nrf2/HO-1 Pathway.

In the present study, ten alkaloids, namely chabamide (1), pellitorine (2), retrofractamide A (3), pyrroperine (4), isopiperolein B (5), piperamide C9:1 (8E) (6), 6,7-dehydrobrachyamide B (7), 4,5-dihydropiperine (8), dehydropipernonaline (9), and piperine (10), were isolated from the fruits of Piper nigrum. Among these, chabamide (1), pellitorine (2), retrofractamide A (3), isopiperolein B (5), and 6,7-dehydrobrachyamide B (7) exhibited significant inhibitory activity on lipopolysaccharide-induced nitric oxide (NO) production in RAW264.7 cells, with IC50 values of 6.8, 14.5, 30.2, 23.7, and 38.5 µM, respectively. Furthermore, compound 1 inhibited lipopolysaccharide-induced NO production in bone marrow-derived macrophages with IC50 value of 9.5 µM. Consistent with NO inhibition, treatment of RAW264.7 cells with chabamide (1), pellitorine (2), and 6,7-dehydrobrachyamide B (7) suppressed expression of inducible NO synthase and cyclooxygenase-2. Chabamide (1), pellitorine (2), and 6,7-dehydrobrachyamide B (7) induced heme-oxygenase-1 expression at the transcriptional level. In addition, compound 1 induced the nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) and upregulated the expression of Nrf2 target genes, NAD(P)H:quinone oxidoreductase 1 and γ-glutamyl cysteine synthetase catalytic subunit, in a concentration-dependent manner in RAW264.7 cells. These findings suggest that chabamide (1) from P. nigrum exert antiinflammatory effects via the activation of the Nrf2/heme-oxygenase-1 pathway; hence, it might be a promising candidate for the treatment of inflammatory diseases. Copyright © 2017 John Wiley & Sons, Ltd.

Formulation Optimization and in Vitro Characterization of Orally Disintegrating Films Using a Factorial Design and Mathematical Modeling for Drug Release.

Even though experimental designs are becoming popular especially for conventional dosage forms, limited studies have been performed to optimize formulations of orally disintegrating films (ODFs). This study aimed to evaluate sildenafil citrate-loaded ODFs for a controlled release with hydroxypropyl methylcellulose as a film-forming polymer. A factorial design was utilized for optimization with three control factors: ethanol ratio, plasticizer ratio, and the type of plasticizer. Tensile strength, disintegration time, water contact angle, and thickness were chosen as responses. For optimization, water contact angle, disintegration time, and thickness were minimized, while the tensile strength was maximized. Based on the conditions, optimal formulations were achieved for each type of plasticizer. Evaluation of desirability indicated that the response values were close to the target. When these optimal formulations were validated, the optimal solutions and target values were similar with small biases. The formulations were characterized using scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, surface pH, in vitro dissolution, and drug release simulation with a mathematical modeling. After the drug was homogenously dispersed throughout the film, the crystalline form of the drug provided strong hydrogen bonds between the drug and the film components. Moreover, it showed a controlled drug release profiles that were well matched with simulated results. This study suggests that the optimized films may present a better alternative to conventional tablets for the treatment of male erectile dysfunction.

DNA Topoisomerase Inhibitory Activity of Constituents from the Fruits of Illicium verum.

Three new compounds, a sesquilignan (1) and two glucosylated phenylpropanoids (2, 3), and seven known compounds (4-10), were isolated from the fruits of Illicium verum HOOK. FIL. (Illiciaceae). The structures of 1-3 were determined based on one and two dimensional (1D- and 2D-) NMR data and electronic circular dichroism (ECD) spectra analyses. Compounds 3, 5, 6, and 8-10 exhibited potent inhibitory activities against topoisomerase II with IC50 values of 54.6, 25.5, 17.9, 12.1, 0.3 and 1.0 µM, respectively, compared to etoposide, the positive control, with an IC50 of 43.8 µM.

Effect of Sipjeondaebo-Tang on the Pharmacokinetics of S-1, an Anticancer Agent, in Rats Evaluated by Population Pharmacokinetic Modeling.

S-1 (TS-1®) is an oral fluoropyrimidine anticancer agent containing tegafur, oteracil, and gimeracil. Sipjeondaebo-tang (SDT) is a traditional oriental herbal medicine that has potential to alleviate chemotherapy-related adverse effects. The aim of the present study was to evaluate the effect of SDT on the pharmacokinetics of S-1. Sprague-Dawley rats were pretreated with a single dose or repeated doses of SDT for seven consecutive days (1200 mg/kg/day). After the completion of pretreatment with SDT, S-1 was orally administered and plasma concentrations of tegafur, its active metabolite 5-FU, and gimeracil were determined by liquid chromatography-tandem mass spectrometry (LC/MS/MS). A population pharmacokinetic model was developed to evaluate the effect of SDT on pharmacokinetics of tegafur and 5-FU. Although a single dose of SDT did not have any significant effect, the absorption rate of tegafur decreased, and the plasma levels of 5-FU reduced significantly in rats pretreated with SDT for seven days in parallel to the decreased gimeracil concentrations. Population pharmacokinetic modeling also showed the enhanced elimination of 5-FU in the SDT-pretreated group. Repeated doses of SDT may inhibit the absorption of gimeracil, an inhibitor of 5-FU metabolism, resulting in enhanced elimination of 5-FU and decrease its plasma level.

Identification of six new lupane-type triterpenoids from Acanthopanax koreanum leaves and their tyrosinase inhibitory activities.

Chemical investigation of Acanthopanax koreanum leaves resulted in the isolation of 13 compounds (1-13), including six new (20,29)-dehydrolupane-type triterpenoids: 3α,11α,30-trihydroxylup-20(29)-en-23,28-dioic acid (1), 3α,11α,30-trihydroxylup-20(29)-en-28-oic acid (2), 3α,11α,30-trihydroxylup-23-al-20(29)-en-28-oic acid (3), 3α, 11α-dihydroxy-20-oxo-30-norlupane-23,28-dioic acid (5), (20S)-3α-hydroxy-30 oxolupane-23,28-dioic acid (8), (20S)-3ß,7ß,29-trihydroxy-lupane-23-al-28-oic acid (10), and one novel compound isolated for the first time, named 3α,20α,29-trihydroxylupane-23,28-dioic acid (9), together with six known compounds (4, 6, 7, and 11-13). Chemical structures of the isolated compounds were evaluated by analyzing and comparing spectroscopic data with those reported in the literature. These compounds were also evaluated for their tyrosinase inhibitory effects. Among them, compounds 3, 7, 9, and 12 showed significant inhibitory effects, with inhibitory concentrations of 50% (IC50) values ranging from 8.61 to 63.5 µM.

Potential pancreatic lipase inhibitory activity of phenolic constituents from the root bark of Morus alba L.

Detailed phytochemical investigation from the root bark of Morus alba resulted in the isolation of eleven new compounds, including seven 2-arylbenzofuran derivatives (morusalfurans A-G), three flavonoids (morusalnols A-C), and one geranylated stilbene (morusibene A), as well as 22 known compounds. The structures of the identified compounds were elucidated based on a comprehensive analysis of spectroscopic data and Mosher's method. Compounds 2, 3, 6-8, 11, 23, 24, and 29 showed potent inhibition of PL in comparison with the positive control treatment (orlistat, IC50=0.012µM), with IC50 values ranging from 0.09 to 0.92µM.

Effects of Constituent Compounds of Smilax china on Nicotine-Induced Endothelial Dysfunction in Human Umbilical Vein Endothelial Cells.

This study investigated the effects of compounds isolated from 70% ethanol (EtOH) extraction of Smilax china L. (SCE), a plant belonging to the family Smilacaceae on nicotine-induced endothelial dysfunction (ED) in human umbilical vein endothelial cells. We isolated 10 compounds from ethyl acetate (EtOAc) fraction of 70% EtOH extract of SCE and investigated their inhibitory effect on nicotine-induced ED in endothelial cells. Kaempferol, kaempferol 7-O-α-L-rhamnopyranoside, puerarin and ferulic acid showed strong inhibition of nicotine-induced vascular cell adhesion molecule (VCAM-1) expression while kaempferol, kaempferin, and caffeic acid attenuated intercellular adhesion molecule (ICAM-1) expression. Lepidoside, caffeic acid and methylsuccinic acid caused the highest up-regulated expression of endothelial nitric oxide synthase at the protein level with caffeic acid and ferulic acid showing strong inhibitory effects on inducible nitric oxide synthase (iNOS) expression. In addition, ferulic acid and kaempferol showed inhibition against interleukin-8 (IL-8) and interleukin-1ß (IL-1ß) expression while ferulic acid and caffeic acid showed comparatively higher inhibition of ED associated tumor necrosis factor-α (TNF-α) expression. These results show the potential of the aforementioned compounds to reverse the toxic effects of nicotine on the endothelium.

DNA Topoisomerase Inhibitory Activity of Constituents from the Flowers of Inula japonica.

Fourteen compounds were isolated from the flowers of Inula japonica THUNB. (Asteraceae), including two new compounds, (1S,2S,4S,5S,8S,10R)-2-acetoxy-4,3-dihydroxy-pseudoguai-7(11)-en-12,8-olide (1) and (1S,2S,4S,5S,8S,10R)-2,4,13-trihydroxy-pseudoguai-7(11)-en-12,8-olide (2), and twelve known compounds, budlein B (3), 6ß-hydroxytomentosin (4), 6-deacetoxybritanin (5), 4-epipulchellin (6), britanin (7), tomentosin (8), (+)-dihydroquercetin (9), (-)-syringaresinol (10), quercetagetin 3,4'-dimethyl ether (11), luteolin (12), britanin G (13) and inuchinenolide C (14). Structures of 1 and 2 were determined based on one and two dimensional (1D)- and (2D)-NMR data and Mosher's esterification method. Compounds 9 and 12 showed inhibitory activities toward DNA topoisomerase I with IC50 values of 55.7 and 37.0 µM, respectively, compared to camptothecin (CPT) with an IC50 of 24.5 µM. Compounds 7-9 and 11-14 exhibited more potent inhibitory activity against topoisomerases II with IC50 values of 6.9, 3.8, 3.0, 6.9, 10.0, 14.7 and 13.8 µM, respectively, than that of etoposide (VP-16) with an IC50 of 26.9 µM. Compounds 4-7 and 10-14 exhibited weak cytotoxicities to the selected cancer cell lines.