Antitumor agents 268. Design, synthesis, and mechanistic studies of new 9-substituted phenanthrene-based tylophorine analogues as potent cytotoxic agents

Substituent-dependent [4+2] or [2+2] cycloadditions of phenylallenyl phosphine oxides with arynes

A [4+2] cycloaddition strategy to assemble phenanthren-9-yldiphenylphosphine oxides is reported. This reaction relies on the strategic use of readily available phenylallenyl phosphine oxides as dienes to participate in [4+2] cycloaddition with arynes. Notably, benzo[b][1,4]oxaphosphinin-4-iums can be controllably synthesized by simply tuning the substituents in the phosphine oxide unit through a [2+2] cycloaddition cascade.

Iodide-Dependent Selective Dehydroaromatization Affording Maleimide-Fused 9,10-Phenanthrenes and Their Analogues

A novel and selective synthesis of polycyclic fused maleimides from easily available raw materials under metal-free conditions is presented. This cascade protocol involves self-condensation of cyclohexanones, followed by Diels-Alder reaction with maleimides, intramolecular dehydration, and selective dehydroaromatization in a one-pot fashion, affording maleimide-fused 9,10-phenanthrenes and their analogues in satisfactory yields. Notably, iodide reagents play a critical role in switching the selectivity toward full or partial dehydrogenation compounds.

Screening of anti-cancerous potential of classical Raudra rasa and modified Raudra rasa modified with hiraka bhasma (nanodiamond) through FTIR & LC-MS analysis

OBJECTIVES

Raudra rasa is an ayurvedic medicine explicitly prescribed for the treatment of arbuda (cancer), whereas hiraka bhasma has the potential to promote cancer healing properties. Together, these two medicines provide multifunction benefits. This paper analyses the functional groups of Raudra rasa modified with hiraka bhasma and compares it with the classically prepared raudra rasa. To identify the functional group, organic ligands, and active compounds present in samples of raudra rasa (CRR) and modified raudra rasa with hiraka bhasma (MRR) contributing to cancer alleviation by using Fourier transform infrared spectroscopy (FTIR) & LC-MS analysis.

METHODS

Classical raudra rasa (CRR), its ingredients, shadguna kajjali (SK); decoction of Piper betel Linn. (PBD); Amaranthus spinosus Linn. (ASD); Boerhaavia diffusa Linn. (BDD); Piper longum Linn. (PLD); cow urine (GM), & similarly modified raudra rasa (MRR), its ingredients, hiraka bhasma (HB); shadguna rasasindura (SHR); water-soluble extract of Piper betel Linn. (PBE); Amaranthus spinosus Linn. (ASE); Boerhaavia diffusa Linn. (BDE); cow urine ark (GA); Piper Longum Linn. (PLE) were subjected to FTIR and LC-MS analysis.

RESULTS

Among all 15 samples studied, maximum numbers of peaks (21) were seen in MRR indicating a greater number of functional groups. Further, in MRR, a maximum peak in the double bond region is suggestive of its higher stability compared to CRR. Both the compound is preliminarily a mixture of the number of functional groups like; fluoro, methyl, amino, hydroxy, nitro, methylamino, carbonyl, and iodo groups, having known anti-proliferative activities. By the FT-IR analysis, the biologically active compounds in aqueous and methanol extract of CRR & MRR were identified that have anti-cancerous compounds. In the present study, a total of 40 major compounds like alkaloids, amino acid, carboxylic acid, Flavonoids, Nucleoside, Nucleotide, phenylpropanoid, Sphingosine, stilbenoid, sugar, phosphate, terpenoids, vitamin from aqueous & methanol extract of CRR & MRR were identified by LC-MS.

CONCLUSIONS

This research paper highlights the presence of different functional groups and bioactive compounds known to have anti-cancer activities. Thus, this review suggests future recommendations for the design and development of improved anticancer drugs with higher efficacy.

Lead Optimization: Synthesis and Biological Evaluation of PBT-1 Derivatives as Novel Antitumor Agents

Phenanthrene-based tylophorine-1 (PBT-1) was identified previously as a lead compound in an anticancer drug discovery effort based on natural Tylophora alkaloids. An expanded structural optimization using a new more efficient synthetic route provided 14 PBT-derivatives. Eleven compounds displayed obvious antiproliferative activities in cellular assays (GI₅₀ 0.55-9.32 μM). The most potent compounds 9c, 9g, and 9h (GI₅₀ < 1 μM) contained a 7-hydroxy group on the phenanthrene B-ring in addition to a pendant piperidine E-ring with different 4-substituents. Compound 9h with NH₂ as the piperidine substituent was at least 4-fold more potent against triple-negative breast cancer MDA-MB-231 than estrogen-responsible breast cancer MCF-7 cell growth. In further biological evaluations, the new active compounds induced cell cycle accumulation in the late S and G2/M phase without interfering with microtubule formation or cell morphology. These results on the optimization of the B- and E-rings of PBT-1 should benefit further development of novel antitumor agents.

Alkaloids as Anticancer Agents: A Review of Chinese Patents in Recent 5 Years

BACKGROUND

In recent years, many novel alkaloids with anticancer activity have been found in China, and some of them are promising for developing as anticancer agents.

OBJECTIVE

This review aims to provide a comprehensive overview of the information about alkaloid anticancer agents disclosed in Chinese patents, and discusses their potential to be developed as anticancer drugs used clinically.

METHODS

Anticancer alkaloids disclosed in Chinese patents in recent 5 years were presented according to their mode of actions. Their study results published on PubMed, and SciDirect databases were presented.

RESULTS

More than one hundred anticancer alkaloids were disclosed in Chinese patents and their mode of action referred to arresting cell cycle, inhibiting protein kinases, affecting DNA synthesis and p53 expression, etc. Conclusion: Many newly found alkaloids displayed potent anticancer activity both in vitro and in vivo, and some of the anticancer alkaloids acted as protein kinase inhibitors or CDK inhibitors possess the potential for developing as novel anticancer agents.

Design, Synthesis and in Vitro Evaluation of Tylophorine Derivatives as Possible Antitumor Agents

Structural simplification and modification of natural products are always very important resources to antitumor drugs. By introducing various aminomethyl groups and amide groups into the phenanthrene ring of tylophorine, a novel series of tylophorine derivatives have been designed and synthesized, and their antiproliferative activities against MCF-7, A549 and HepG-2 cells have been evaluated, too. The results indicated that most of the prepared compounds exhibited good antitumor activities. Especially, one compound with an {ethyl[2-(morpholin-4-yl)ethyl]amino}methyl group at the side chain exhibited the most significant cytotoxic effects.

Pd(II)-Catalyzed One-Pot Multiple C-C Bond Formation: En Route Synthesis of Succinimide-Fused Unsymmetrical 9,10-Dihydrophenanthrenes from Aryl Iodides and Maleimides

An expeditious approach has been developed for the synthesis of succinimide-fused unsymmetrical 9,10-dihydrophenanthrenes from simple aryl iodides and maleimides. The developed transformation, overall proceeding with high regioselectivity via a cascade approach through palladium(II)-catalyzed Micheal-type addition/C-H activation/intramolecular cross-dehydrogenative coupling (ICDC)/C-H activation, allows formation of four fundamental carbon-carbon bonds in one-pot fashion. The reactions tolerate broad functional groups and satisfy the parameters of atom and step economy. Detailed mechanistic studies were carried out to support the proposed synthetic pathway.

Cu(I)-Catalyzed Ligand-Free Tandem One-Pot or Sequential Annulation via Knoevenagel Intermediates: An Entry into Multifunctional Naphthalenes, Phenanthrenes, Quinolines, and Benzo[b]carbazoles

A simple but efficient one-pot or sequential copper-catalyzed protocol using 2-bromoaldehydes and active methylene group containing substrates that affords multifunctional naphthalenes, phenanthrenes, quinolines, and benzo[b]carbazoles via Knoevenagel condensation, C-arylation, and decarboxylation, followed by aromatization, is developed. The reaction utilizes the potential of Knoevenagel intermediates and does not require any ancillary ligand. The phenanthrene products thus obtained show moderate fluorescence activity. Structural elaboration of the products to obtain dihydrobenzoquinazolines is also highlighted.

Tylophorine: Sources, Properties, Applications and Biotechnological Production

Tylophora indica, a medicinal climber, belongs to the family, Asclepiadaceae. Roots and leaves of the plant contain several alkaloids including tylophorine, tylophorinine and tylophrinidine. The major alkaloid, tylophorine found in T. indica possesses several properties, such as immunosuppressive, antitumour, antifeedant, antibacterial, antifungal, antiamoebic, diuretic and hepatoprotective activities. In addition to this, tylophorine provides positive stimulation to adrenal cortex. Biotechnological production of tylophorine was fulfilled by inducing hairy roots mediated by Agrobacterium rhizogenes (A4 strain). It was followed by its growth in liquid suspension culture that could yield maximum biomass and tylophorine production. This type of liquid suspension culture yielded 9.8 ± 0.21 mgL⁻¹ tylophorine within 4–6 weeks of incubation. Maceration technique employed for the extraction of tylophorine was the most viable and efficient protocol. Although many reports are available regarding the biotechnological production of tylophorine, its competent and economic production still continues as a problematic issue.

Transition-metal-free catalyzed [3+2] cycloadditions/oxidative aromatization reactions for the synthesis of annulated indolizines

A transition-metal-free catalyzed [3+2] cycloadditions/oxidative aromatization three-component reactions for direct construction of annulated indolizines was reported.

Further insight into the photochemical behavior of 3-aryl-N-(arylsulfonyl)propiolamides: tunable synthetic route to phenanthrenes

Reported herein is further insight into the photochemical behaviour of 3-aryl-N-(arylsulfonyl)-propiolamides, which provides a straightforward way to access meaningful phenanthrenes.

Tylophorine Analog DCB-3503 Inhibited Cyclin D1 Translation through Allosteric Regulation of Heat Shock Cognate Protein 70

Tylophorine analog DCB-3503 is a potential anticancer and immunosuppressive agent that suppresses the translation of cellular regulatory proteins, including cyclin D1, at the elongation step. However, the molecular mechanism underlying this phenomenon remains unknown. This study demonstrates that DCB-3503 preferentially binds to heat shock cognate protein 70 (HSC70), which is a determinant for cyclin D1 translation by binding to the 3′-untranslated region (3′ UTR) of its mRNA. DCB-3503 allosterically regulates the ATPase and chaperone activities of HSC70 by promoting ATP hydrolysis in the presence of specific RNA binding motifs (AUUUA) of cyclin D1 mRNA. The suppression of cyclin D1 translation by DCB-3503 is not solely caused by perturbation of the homeostasis of microRNAs, although the microRNA processing complex is dissociated with DCB-3503 treatment. This study highlights a novel regulatory mechanism of protein translation with AUUUA motifs in the 3′ UTR of mRNA by HSC70, and its activity can be allosterically modulated by DCB-3503. DCB-3503 may be used to treat malignancies, such as hepatocellular carcinoma or breast cancer with elevated expression of cyclin D1.

Intramolecular Dehydrogenative Coupling of 2,3-Diaryl Acrylic Compounds: Access to Substituted Phenanthrenes

A simple, facile, and environmentally benign intramolecular dehydrogenative coupling of various 1,2-diarylethylenes for the synthesis of phenanthrenes in excellent yield has been described. This new methodology uses ceric ammonium nitrate (CAN) as a promoter at room temperature and has been extended to intermolecular synthesis of biaryl compounds. The electron transfer from methoxyarene to cerium leads to cationic radical formation, which further proceeds to intramolecular coupling. Preliminary mechanistic investigation by EPR spectroscopy and density functional theory calculation suggested a similar view.

Design, Synthesis, and Biological Activity of Sulfonamide Analogues of Antofine and Cryptopleurine as Potent and Orally Active Antitumor Agents

Due to their profound antiproliferative activity and unique mode of action, phenanthroindolizidine and phenanthroquinolizidine alkaloids, represented by antofine and cryptopleurine, have attracted attention recently as potential therapeutic agents. We have designed, synthesized, and evaluated the methanesulfonamide analogues of these natural alkaloids with the hope of improving their druglikeness. The analogues showed enhanced growth inhibition of human cancer cells compared with the parent natural products. In particular, a methanesulfonamide analogue of cryptopleurine (5b) exhibited improved bioavailability and significant antitumor activity, which suggests that 5b is a promising new anticancer agent. Our studies suggest that the inhibition of cancer cell growth by 5b is associated with the induction of G0/G1 cell cycle arrest via nicotinamide N-methyltransferase-dependent JNK activation in Caki-1 renal cancer cells. In addition, compound 5b significantly inhibited the migration and invasion of Caki-1 cancer cells by modulating the p38 MAPK signaling pathway.

Directed Metalation-Suzuki-Miyaura Cross-Coupling Strategies: Regioselective Synthesis of Hydroxylated 1-Methyl-phenanthrenes

A general, efficient, and regioselective synthesis of a series of hydroxylated 1-methylphenanthrenes 9 by a combined directed ortho metalation (DoM)-Suzuki-Miyaura cross-coupling-directed remote metalation (DreM) sequence is reported. Diversity to this methodology was achieved by a regioselective DoM rather than DreM reaction, affording more highly substituted phenanthrols ( Table 2 ). Application of the turbo-Grignard reagent (i-PrMgCl·LiCl) in the Ni-catalyzed Corriu-Kumada reaction gave efficient decarbamoylation ( Tables 3 and 4 ). Additional features are the TMS protecting group and halo-induced ipso-desilylation tactics applied to the regioselective synthesis of phenanthrenes ( Scheme 2 ).

Reformulating Tylocrebrine in Epidermal Growth Factor Receptor Targeted Polymeric Nanoparticles Improves Its Therapeutic Index

Several promising anticancer drug candidates have been sidelined owing to their poor physicochemical properties or unfavorable pharmacokinetics, resulting in high overall cost of drug discovery and development. Use of alternative formulation strategies that alleviate these issues can help advance new molecules to the clinic at a significantly lower cost. Tylocrebrine is a natural product with potent anticancer activity. Its clinical trial was discontinued following the discovery of severe central nervous system toxicities. To improve the safety and potency of tylocrebrine, we formulated the drug in polymeric nanoparticles targeted to the epidermal growth factor receptor (EGFR) overexpressed on several types of tumors. Through in vitro studies in different cancer cell lines, we found that EGFR targeted nanoparticles were significantly more effective in killing tumor cells than the free drug. In vivo pharmacokinetic studies revealed that encapsulation in nanoparticles resulted in lower brain penetration and enhanced tumor accumulation of the drug. Further, targeted nanoparticles were characterized by significantly enhanced tumor growth inhibitory activity in a mouse xenograft model of epidermoid cancer. These results suggest that the therapeutic index of drugs that were previously considered unusable could be significantly improved by reformulation. Application of novel formulation strategies to previously abandoned drugs provides an opportunity to advance new molecules to the clinic at a lower cost. This can significantly increase the repertoire of treatment options available to cancer patients.

Methylenedioxy flavonoids: assessment of cytotoxic and anti-cancer potential in human leukemia cells

A new series of chalcones, flavanones and flavones with methylenedioxy group at the 3',4' position in chalcone, 7,8 position in flavanones and flavones with mono-, di- and trimethoxy groups in the benzaldehyde ring have been assessed for their effect on proliferation, cytotoxic potential and apoptosis in human leukemia cells. Among the tested compounds, the chalcone series showed the best activity and chalcone 3 (mono methoxy group at the ortho position in A-ring) showed a significant effect on down-regulation of cancer cell proliferation and viability in three different leukemia cell lines (K562, Jurkat, U937). The executioner caspase cleavage analyses indicated that the cytotoxic effect mediated by chalcone 3 is due to induction of apoptotic cell death. Interestingly, the cytotoxic effect was cell type-specific and targeted preferentially cancer cells as peripheral blood mononuclear cells (PBMCs) from healthy donors were less affected by the treatment compared to K562, Jurkat and U937 leukemia cells. Altogether our results indicate a potential drug candidate with interesting differential toxicity obeying Lipinski's rule of five.

The antitumor agent PBT-1 directly targets HSP90 and hnRNP A2/B1 and inhibits lung adenocarcinoma growth and metastasis

Natural products are the major sources of currently available anticancer drugs. We recently reported that phenanthrene-based tylophorine derivative-1 (PBT-1) may be a potential antitumor agent for lung adenocarcinoma. We therefore examined the direct targets of PBT-1 and their effects in inhibiting lung adenocarcinoma. We found that PBT-1 reduced the level of Slug and inhibits the migration, invasion, and filopodia formation of lung adenocarcinoma CL1-5 cells in vitro. In addition, PBT-1 displayed in vivo antitumor and antimetastasis activities against subcutaneous and orthotopic xenografts of CL1-5 cells in nude mice. Chemical proteomics showed that heat shock protein 90 (HSP90) and heterogeneous nuclear ribonucleoproteins A2/B1 (hnRNP A2/B1) bound PBT-1 in CL1-5 cells. Inhibition of HSP90 and hnRNP A2/B1 reduced the activation of AKT and Slug expression. Taken together, these findings suggest that PBT-1 binds to HSP90 and/or hnRNP A2/B1 and initiates antitumor activities by affecting Slug- and AKT-mediated metastasis and tumorigenesis.

Antofine-induced connexin43 gap junction disassembly in rat astrocytes involves protein kinase Cβ

Antofine, a phenanthroindolizidine alkaloid derived from Cryptocaryachinensis and Ficusseptica in the Asclepiadaceae milkweed family, is cytotoxic for various cancer cell lines. In this study, we demonstrated that treatment of rat primary astrocytes with antofine induced dose-dependent inhibition of gap junction intercellular communication (GJIC), as assessed by scrape-loading 6-carboxyfluorescein dye transfer. Levels of Cx43 protein were also decreased in a dose- and time-dependent manner following antofine treatment. Double-labeling immunofluorescence microscopy showed that antofine (10ng/ml) induced endocytosis of surface gap junctions into the cytoplasm, where Cx43 was co-localized with the early endosome marker EEA1. Inhibition of lysosomes or proteasomes by co-treatment with antofine and their respective specific inhibitors, NH4Cl or MG132, partially inhibited the antofine-induced decrease in Cx43 protein levels, but did not inhibit the antofine-induced inhibition of GJIC. After 30min of treatment, antofine induced a rapid increase in the intracellular Ca(2+) concentration and activation of protein kinase C (PKC)α/βII, which was maintained for at least 6h. Co-treatment of astrocytes with antofine and the intracellular Ca(2+) chelator BAPTA-AM prevented downregulation of Cx43 and inhibition of GJIC. Moreover, co-treatment with antofine and a specific PKCβ inhibitor prevented endocytosis of gap junctions, downregulation of Cx43, and inhibition of GJIC. Taken together, these findings indicate that antofine induces Cx43 gap junction disassembly by the PKCβ signaling pathway. Inhibition of GJIC by antofine may undermine the neuroprotective effect of astrocytes in CNS.

Antitumor agents 295. E-ring hydroxylated antofine and cryptopleurine analogues as antiproliferative agents: design, synthesis, and mechanistic studies

Various E-ring hydroxylated antofine and cryptopleurine analogues were designed, synthesized, and tested against five human cancer cell lines. Interesting structure-activity relationship (SAR) correlations were found among these new compounds. The most potent compound 13b was further tested against a series of nonsmall cell lung cancer (NSCLC) cell lines in which it showed impressive antiproliferative activity. Mechanistic studies revealed that 13b is able to down-regulate HSP90 and β-catenin in A549 lung adenocarcinoma cells in a dose-dependent manner, suggesting a potential use for treating hedgehog pathway-driven tumorigenesis.

Synthesis, biological evaluation and mechanism studies of deoxytylophorinine and its derivatives as potential anticancer agents

Previous studies indicated that (+)-13a-(S)-deoxytylophorinine (1) showed profound anti-cancer activities both in vitro and in vivo and could penetrate the blood brain barrier to distribute well in brain tissues. CNS toxicity, one of the main factors to hinder the development of phenanthroindolizidines, was not obviously found in 1. Based on its fascinating activities, thirty-four derivatives were designed, synthesized; their cytotoxic activities in vitro were tested to discover more excellent anticancer agents. Considering the distinctive mechanism of 1 and interesting SAR of deoxytylophorinine and its derivatives, the specific impacts of these compounds on cellular progress as cell signaling transduction pathways and cell cycle were proceeded with seven representative compounds. 1 as well as three most potent compounds, 9, 32, 33, and three less active compounds, 12, 16, 35, were selected to proform this study to have a relatively deep view of cancer cell growth-inhibitory characteristics. It was found that the expressions of phospho-Akt, Akt, phospho-ERK, and ERK in A549 cells were greater down-regulated by the potent compounds than by the less active compounds in the Western blot analysis. To the best of our knowledge, this is the first report describing phenanthroindolizidines alkaloids display influence on the crucial cell signaling proteins, ERK. Moreover, the expressions of cyclin A, cyclin D1 and CDK2 proteins depressed more dramatically when the cells were treated with 1, 9, 32, and 33. Then, these four excellent compounds were subjected to flow cytometric analysis, and an increase in S-phase was observed in A549 cells. Since the molecular level assay results of Western blot for phospho-Akt, Akt, phospho-ERK, ERK, and cyclins were relevant to the potency of compounds in cellular level, we speculated that this series of compounds exhibit anticancer activities through blocking PI3K and MAPK signaling transduction pathways and interfering with the cell cycle progression.

Analogue-based approaches in anti-cancer compound modelling: the relevance of QSAR models

BACKGROUND

QSAR is among the most extensively used computational methodology for analogue-based design. The application of various descriptor classes like quantum chemical, molecular mechanics, conceptual density functional theory (DFT)- and docking-based descriptors for predicting anti-cancer activity is well known. Although in vitro assay for anti-cancer activity is available against many different cell lines, most of the computational studies are carried out targeting insufficient number of cell lines. Hence, statistically robust and extensive QSAR studies against 29 different cancer cell lines and its comparative account, has been carried out.

RESULTS

The predictive models were built for 266 compounds with experimental data against 29 different cancer cell lines, employing independent and least number of descriptors. Robust statistical analysis shows a high correlation, cross-validation coefficient values, and provides a range of QSAR equations. Comparative performance of each class of descriptors was carried out and the effect of number of descriptors (1-10) on statistical parameters was tested. Charge-based descriptors were found in 20 out of 39 models (approx. 50%), valency-based descriptor in 14 (approx. 36%) and bond order-based descriptor in 11 (approx. 28%) in comparison to other descriptors. The use of conceptual DFT descriptors does not improve the statistical quality of the models in most cases.

CONCLUSION

Analysis is done with various models where the number of descriptors is increased from 1 to 10; it is interesting to note that in most cases 3 descriptor-based models are adequate. The study reveals that quantum chemical descriptors are the most important class of descriptors in modelling these series of compounds followed by electrostatic, constitutional, geometrical, topological and conceptual DFT descriptors. Cell lines in nasopharyngeal (2) cancer average R2 = 0.90 followed by cell lines in melanoma cancer (4) with average R2 = 0.81 gave the best statistical values.

Antitumor agents 288: design, synthesis, SAR, and biological studies of novel heteroatom-incorporated antofine and cryptopleurine analogues as potent and selective antitumor agents

Novel heteroatom-incorporated antofine and cryptopleurine analogues were designed, synthesized, and tested against a panel of five cancer cell lines. Two new S-13-oxo analogues (11 and 16) exhibited potent cell growth inhibition in vitro (GI(50): 9 nM and 20 nM). Interestingly, both compounds displayed improved selectivity among different cancer cell lines, in contrast to the natural products antofine and cryptopleurine. Mechanism of action (MOA) studies suggested that R-antofine promotes dysregulation of DNA replication during early S phase, while no similar effects were observed for 11 and 15 on corresponding replication initiation complexes. Compound 11 also showed greatly reduced cytotoxicity against normal cells and moderate antitumor activity against HT-29 human colorectal adenocarcinoma xenograft in mice without overt toxicity.

Design, synthesis, and antiviral evaluation of phenanthrene-based tylophorine derivatives as potential antiviral agents

A series of C9-substituted phenanthrene-based tylophorine derivatives (PBTs) were designed, synthesized, and first evaluated for their antiviral activities against tobacco mosaic virus (TMV). These compounds contain a phenanthrene core structure and can be synthesized some efficiently with excellent yields compared with tylophorine alkaloid. The bioassay results show that some of these compounds exhibited higher antiviral activity against TMV in vivo than tylophorine and commercial Ningnanmycin. Especially, compounds 3, 4, 9, 13, and 16 emerged as potential inhibitors of plant virus. These new findings demonstrate that these phenanthrene-based tylophorine derivatives (PBTs) represent another new template for antiviral studies and could be considered for novel therapy against plant virus infection.

Synthesis and antitumor activities of phenanthrene-based alkaloids

A series of phenanthrene-based tylophorine derivatives (PBTs) were synthesized and their cytotoxic activities against the H460 human large-cell lung carcinoma cell line were evaluated. Among these compounds, N-(3-hydroxy-2,6,7-tri-methoxyphenanthr-9-ylmethyl)-L-prolinol (5a), and N-(3-hydroxy-2,6,7-trimethoxy-phenanthr-9-ylmethyl)-L-valinol (9) exhibited good activities, with IC(50) values of 11.6 and 6.1 microM, respectively.