Synthesis and antiproliferative activity of novel sugiol beta-amino alcohol analogs

InI3-catalyzed polyene cyclization of allenes and its application in the total synthesis of seven abietane-type diterpenoids

A novel polyene cyclization using the allene group as the initiator has been successfully developed. This methodology provides an efficient strategy for the construction of an abietane-type tricyclic skeleton with a functionalizable C2-C3 double bond and features a wide substrate scope and excellent stereoselectivities. Potential utility of this approach has been well demonstrated by the collective total synthesis of seven abietane-type diterpenoids. Specifically, (±)-2,3-dihydroxyferruginol and (±)-2,3-dihydroxy-15,16-dinor-ent-pimar-8,11,13-triene were synthesized for the first time.

Sugiol suppresses the growth, migration, and invasion of human endometrial cancer cells via induction of apoptosis and autophagy

Recently, diterpenoids have been shown to exhibit several health benefits including cancer prevention. In the present study, we examined the anticancer effects of sugiol diterpene against the endometrial carcinoma and attempted to explore the underlying mechanisms. The results showed that sugiol significantly (P < 0.05) inhibited the proliferation of the endometrial carcinoma cell lines (HEC-1-A, HEC-1-B, and KLE) as compared to the normal THESCs cells. The IC₅₀ of sugiol against all the three endometrial carcinoma cell lines ranged between 14 and 18 µM as against an IC₅₀ of 110 μM against the normal THESCs cells. Sugiol caused several changes in the morphology of the HEC-1-B cells characteristic of apoptosis. The DAPI and annexin PI assays confirmed the induction of apoptosis in HEC-1-B cells. Sugiol also triggered increase in Bax and decrease in Bcl-2 expression. The acridine orange staining revealed that the formation of autolysosomes in HEC-1-B cells upon treatment with sugiol suggestive of autophagy. The autophagy was further confirmed by increase in the expression of LC3B-II, Beclin-1, Atg5, and Atg12 and decrease in the expression of P62. The transwell assay showed that relative to the untreated HEC-1-B cells, the migration and invasion of the sugiol-treated HEC-1-B cells was significantly (P < 0.05) inhibited. Collectively, the finding of the present study revealed that sugiol suppresses the growth of human endometrial cells via induction of apoptosis and autophagy. Consistently, sugiol may prove to be an important lead molecule in the development of chemotherapy for endometrial carcinoma.

Anticancer activity of sugiol against ovarian cancer cell line SKOV3 involves mitochondrial apoptosis, cell cycle arrest and blocking of the RAF/MEK/ERK signalling pathway

INTRODUCTION

Ovarian cancer is one of the leading causes of cancer-related deaths in women. Treatments for ovarian cancer include surgery followed by chemotherapy. However, the survival rate for ovarian cancer is still not satisfactory. Moreover, the current chemotherapy has numerous associated side effects. Therefore there is an urgent need to look for novel and more viable treatment options. Against this backdrop the present study was designed to evaluate the anticancer activity of sugiol against ovarian cancer cells.

MATERIAL AND METHODS

Cell viability was assessed by CCK8 assay, apoptosis by DAPI, AO/ER and annexin V/PI staining. Mitochondrial membrane potential and cell cycle analysis was performed by flow cytometry. Cell migration was investigated by wound healing assay. Protein expression was monitored by western blotting.

RESULTS

The results of the present study indicated that sugiol exerts significant (p < 0.0001) anticancer effects on SKOV3 cancer cells with an IC₅₀ of 25 μM. However, sugiol exhibited less cytotoxicity against normal ovarian cells with an IC₅₀ of 62.5 μM. The anticancer effects of sugiol were found to be due to G0/G1 cell cycle arrest and mitochondrial apoptosis. Sugiol also inhibited cell migration of SKOV3 cells dose dependently. Moreover, the results showed that sugiol could inhibit the RAF/MEK/ERK signalling pathway in a dose-dependent manner.

CONCLUSIONS

The results of the present study indicate that sugiol exerts potent anticancer effects on SKOV3 cells via induction of cell cycle arrest, mitochondrial apoptosis and inhibition of the RAF/MEK/ERK signalling pathway.

Synthesis and Biological Studies of (+)-Liquiditerpenoic Acid A (Abietopinoic Acid) and Representative Analogues: SAR Studies

The first semisynthesis and biological profiling of the new abietane diterpenoid (+)-liquiditerpenoic acid A (abietopinoic acid) (7) along with several analogues are reported. The compounds were obtained from readily available methyl dehydroabietate (8), which was derived from (-)-abietic acid (1). Biological comparison was conducted according to the different functional groups, leading to some basic structure-activity relationships (SAR). In particular, the ferruginol and sugiol analogues 7 and 10-16 were characterized by the presence of an acetylated phenolic moiety, an oxidized C-7 as a carbonyl, and a different functional group at C-18 (methoxycarbonyl, carboxylic acid, and hydroxymethyl). The biological properties of these compounds were investigated against a panel of six representative human tumor solid cells (A549, HBL-100, HeLa, SW1573, T-47D, and WiDr), five leukemia cellular models (NALM-06, KOPN-8, SUP-B15, UoCB1, and BCR-ABL), and four Leishmania species ( L. infantum, L. donovani, L. amazonensis, and L. guyanensis). A molecular docking study pointed out some targets in these Leishmania species. In addition, the ability of the compounds to modulate GABA_A receptors (α₁β₂γ_2s) is also reported. The combined findings indicate that these abietane diterpenoids offer a source of novel bioactive molecules with promising pharmacological properties from cheap chiral-pool building blocks.

Synthesis of Novel Podocarpa-8,11,13-Triene-7- and 13-Nitriles and Evaluation of their Anti-Inflammatory and Cytotoxic Activity

A series of novel podocarpa-8,11,13-triene-7- and 13-nitriles were prepared from the naturally occurring labdane diterpenoid (+)-manool, using podocarp-8(14)-en-13-one and 13-methoxypodocarpa-8,11,13-trien-7-one as key intermediates and TMSCN and acetonitrile as source of the nitrile. The synthesised compounds were screened for cytotoxicity against mouse macrophage cell line (RAW 264.7), human colon adenocarcinoma cell lines (HT-29) and human prostate adenocarcinoma cell lines (PC3) and for anti-inflammatory, as measured by the inhibition of nitric oxide (NO) production by RAW cells. 7-Oxopodocarpa-8,11,13-triene-13-nitrile exhibited significant inhibition of NO production (IC50 = 6 μM) and was not cytotoxic.

Abietane diterpenoids from Caryopteris incana (Thunb.) Miq

Twelve new diterpenes, caryopincaolide A-L (1-4, 11-12, 16-19, 27-28), together with twenty-eight known diterpenes, have been isolated from the whole plant of Caryopteris incana (Thunb.) Miq. Their structures were elucidated on the basis of 1D and 2D NMR, IR, X-ray crystal diffraction and mass spectroscopic data, as well as ECD calculations. All compounds were tested for in vitro dipeptidyl peptidase IV (DPP-IV) inhibitory activity, with compounds 3, 4, 28, 29, and 40 exhibiting DPP-IV inhibitory effects with IC50 values ranging from 54.2 to 228.9 μM. Compounds 1, 3 and 4 also showed potent activity toward the inhibition of the growth of human cancer cells and 1 can induce apoptosis in Hey and A-549 cells.

Crystal structure of 5-hy-droxy-methyl-2-meth-oxy-phenol

In the title compound, C8H10O3, the hy-droxy-methyl group is twisted by 74.51 (13)° from the plane of the benzene ring to which it is connected. By contrast, the benzene and meth-oxy groups are almost coplanar, making a dihedral angle of 4.0 (2)°. In the crystal, O-H⋯O hydrogen bonds link the mol-ecules into a three-dimensional network.

A domino synthetic approach for new, angular pyrazol- and isoxazol-heterocycles using [DBU][Ac] as an effective reaction medium

Some new, angular pyrazol- and isoxazol-heterocycles have been synthesized by the reaction of pyrazolone/isoxazolone with typical ketone-based substrates—O-alkenyloxy/alkynyloxy-acetophenones.

Synthetic derivatives of aromatic abietane diterpenoids and their biological activities

Naturally occurring aromatic abietane diterpenoids (dehydroabietanes) exhibit a wide range of biological activities. A number of synthetic studies aimed at modifying the abietane skeleton in order to obtain new potential chemotherapeutic agents have been reported. In this study, the biological activities of synthetic derivatives of aromatic abietane diterpenoids are reviewed.

Abietane diterpenoids from Isodon lophanthoides var. graciliflorus and their cytotoxicity

Seven new (1-7) and three known (8-10) abietane diterpenoids were isolated from the methanolic extract of the aerial parts of Isodon lophanthoides var. graciliflorus (Lamiaceae), a folk Chinese medicine and an herb for functional beverages. They were identified as 16-acetoxylsugiol (1), graciliflorin E (2), graciliflorin F (3), 15-O-methylgraciliflorin F (4), 15-hydroxy-20-deoxocarnosol (5), 3β-hydroxysempervirol (6), 15-hydroxy-1-oxosalvibretol (7), abieta-8,11,13-triene-14,19-diol (8), 6,12,15-trihydroxy-5,8,11,13-abietatetraen-7-one (9), and 3α-hinokiol (10) based on the spectroscopic data including COSY (correlated spectroscopy), HMBC (heteronuclear multiple bond correlation), and HR-ESI-MS (high-resolution electrospray ionization mass spectrometry). All the compounds except 10 were obtained from I. lophanthoides for the first time. Compounds 1, 2, 5, 6, 8, and 9 exhibited in vitro cytotoxicity against A549 (human lung adenocarcinoma), MCF-7 (human breast adenocarcinoma), and HeLa (human cervical carcinoma) cell lines with the IC(50) values of 1.79-52.67 μM.

Synthesis and antibacterial evaluation of New N-acylhydrazone derivatives from dehydroabietic acid

A series of new N-acylhydrazone derivatives were synthesized in good yields through the reactions of dehydroabietic acid hydrazide with a variety of substituted arylaldehydes. The structures of the synthesized compounds were confirmed by IR, 1H- and 13C-NMR, ESI-MS, elemental analysis and single crystal X-ray diffraction. From the crystal structure of compound 4l, the C=N double bonds of these N-acylhydrazones showed (E)-configuration, while the NMR data of compounds 4a-q indicated the existence of two rotamers for each compound in solution. The target compounds were evaluated for their antibacterial activities against four microbial strains. The result suggested that several compounds exhibited pronounced antibacterial activities. Particularly, compound 4p exhibited good antibacterial activity against Staphylococcus aureus and Bacillus subtilis comparable to positive control. The possible antibacterial metabolism and the strategy for further optimization of this compound were also discussed.

Synthesis, characterization, anti-inflammatory and in vitro antimicrobial activity of some novel alkyl/aryl substituted tertiary alcohols

The synthesis of some novel alkyl/aryl substituted tertiary alcohols was accomplished in two steps. The synthetic route involves preparation of Grignard reagents by treating alkyl/aryl bromides with magnesium turnings in dry ether. Then substituted chalcones were reacted with the Grignard reagents to afford alkyl/aryl substituted tertiary alcohols 1-10. The structures of the synthesized compounds were assigned on the basis of FT-IR, 1H-NMR, 13C-NMR and mass spectroscopic data. The in vivo anti-inflammatory activity of the synthesized compounds was evaluated using the carrageenan-induced hind paw edema method and was compared with that of ibuprofen. Some of the newly synthesized compounds showed promising anti-inflammatory activity. The tertiary alcohols 1-10 were also screened for antibacterial activity against ten bacterial strains using seven Gram-positive and three Gram-negative bacteria and for antifungal activity against Aspergillus Flavus, Aspergillus Niger and Aspergillus pterus. Tertiary alcohols 1-10 were found to exhibit good to excellent antimicrobial activities compared to levofloxacin and fluconazole used as standard drugs.

Design, synthesis and cytotoxic activities of novel β-amino alcohol derivatives

Three series of novel β-amino alcohols possessing an N-anthranyl group have been obtained using tryptophan as the major starting material. These compounds were screened for cytotoxic activity against five human cancer cell lines in vitro by MTT assay, and some of them exhibited potential ability to be anticancer agents. Structure-activity relationship was carefully investigated. Only the compounds possessing small substituents (H or CH(3)) at C-6 position showed the same activity as cisplatin (DDP) did.