Prediction of Efficacy for Atezolizumab/Bevacizumab in Unresectable Hepatocellular Carcinoma with Hepatobiliary-Phase Gadolinium Ethoxybenzyl-Diethylenetriaminepentaacetic Acid MRI

BACKGROUND

This study aimed to examine whether the coefficient of variation (CV) in the hepatobiliary-phase (HBP) of Gd-EOB-DTPA-MRI could be an independent predictive factor for tumor progression.

METHODS

Patients who underwent Gd-EOB-DTPA-MRI before Atezolizumab/bevacizumab therapy at six affiliated institutions between 2018 and 2022 were included. CV for each patient was calculated as the mean value for up to five tumors larger than 10 mm, and CV of the whole tumor was calculated using LIFEx software. The tumor response was evaluated within 6-10 weeks. The primary endpoint was to investigate the predictive factors, including CV, related to tumor progression using logistic regression analysis. The secondary endpoints were tumor response rate and progression-free survival (PFS) based on CV.

RESULTS

Of the 46 enrolled patients, 13 (28.3%) underwent early progressive disease. Multivariate analysis revealed that a high CV (≥0.22) was an independent predictive factor for tumor progression (p = 0.043). Patients with a high CV had significantly frequent PD than those with a low CV (43.5 vs. 13.0%, p = 0.047). Patients with a high CV tended to have shorter PFS than those with a low CV (3.5 vs. 6.7 months, p = 0.071).

CONCLUSION

Quantitative analysis using CV in the HBP of Gd-EOB-DTPA-MRI may be useful for predicting tumor progression for atezolizumab/bevacizumab therapy.

Effects of Short-Term Lenvatinib Administration Prior to Transarterial Chemoembolization for Hepatocellular Carcinoma

AIM

Transarterial chemoembolization (TACE) combined with lenvatinib, employing a 4-day lenvatinib administration followed by TACE without an interval (short-term LEN-TACE), was performed for hepatocellular carcinoma (HCC). The aim was to assess tumor hemodynamics following the 4-day lenvatinib and to evaluate the treatment outcomes after the short-term LEN-TACE.

METHODS

25 unresectable HCC patients received this combined therapy. Lenvatinib (4-12 mg) was administrated for 4 days prior to TACE. Perfusion CT scans were obtained before and after the lenvatinib administration. Either cTACE (76%) or DEB-TACE (24%) were performed.

RESULTS

intra-tumor blood flow significantly decreased after the 4-day lenvatinib (p < 0.05). The TACE procedure was successful with no severe adverse events in all patients. The overall complete response (CR) rate was 75% (cTACE 84%, DEB-TACE 40%). The lipiodol-washout ratio between 1 week and 4 months after cTACE correlated with the arterial flow reduction ratio by lenvatinib prior to TACE (r = -0.55). The 12-month progression-free survival (PFS) rate was 75.0%.

CONCLUSIONS

The short-term LEN-TACE is feasible and safe, demonstrating promising outcomes with a high CR ratio, contributing to lipiodol retention in the tumor after cTACE, and extended PFS. To confirm the advantages of this treatment protocol, a prospective clinical trial is mandatory.

Pictorial Review of Pleural Disease: Multimodality Imaging and Differential Diagnosis

The pleura is a thin, smooth, soft-tissue structure that lines the pleural cavity and separates the lungs from the chest wall, consisting of the visceral and parietal pleurae and physiologic pleural fluid. There is a broad spectrum of normal variations and abnormalities in the pleura, including pneumothorax, pleural effusion, and pleural thickening. Pneumothorax is associated with pulmonary diseases and is caused by iatrogenic or traumatic factors. Chest radiography and US help detect pneumothorax with various signs, and CT can also help assess the causes. Pleural effusion occurs in a wide spectrum of diseases, such as heart failure, cirrhosis, asbestos-related diseases, infections, chylothorax, and malignancies. Chest US allows detection of a small pleural effusion and evaluation of echogenicity or septa in pleural effusion. Pleural thickening may manifest as unilateral or bilateral and as focal, multifocal, or diffuse. Various diseases can demonstrate pleural thickening, such as asbestos-related diseases, neoplasms, and systemic diseases. CT, MRI, and fluorodeoxyglucose (FDG) PET/CT can help differentiate between benign and malignant lesions. Knowledge of these features can aid radiologists in suggesting diagnoses and recommending further examinations with other imaging modalities. The authors provide a comprehensive review of the clinical and multimodality imaging findings of pleural diseases and their differential diagnoses. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Multimodality Imaging of Primary Hepatic Lymphoma: A Case Report and a Literature Review

Primary hepatic lymphoma (PHL) is a rare form of non-Hodgkin lymphoma primarily affecting the liver. We present a case of an 84-year-old man diagnosed with PHL, incidentally detected during abdominal ultrasonography. The ultrasonography showed a hypoechoic nodule. When examined by CEUS, the nodule showed hyperenhancement in the arterial phase and hypoenhancement in the portal and late phases. Conversely, CECT demonstrated hypoenhancement through all the phases. The patient declined a tumor biopsy and opted for follow-up care. Ten months later, the lobular mass had increased from 15 mm to 65 mm, presenting as hypoechogenic and demonstrating the "vessel-penetrating sign" on color Doppler imaging. CEUS revealed reticulated enhancement, indicating intratumoral vessels. The mass displayed hypoattenuation on plain CT, hypointensity in T1-weighted images, and hyperintensity in T2-weighted images and exhibited significant restriction in diffusion-weighted images. Both CECT and contrast-enhanced MRI exhibited hypoenhancement. The patient underwent a partial hepatic segmentectomy, and the mass was pathologically diagnosed as a diffuse large B-cell lymphoma. Subsequent postoperative radiological examinations revealed no other lesions, confirming the diagnosis of PHL. Our report highlights specific ultrasonographic signs of PHL observed from an early stage and presents a review of the relevant literature.

Effect of further substitutions at 5-, 6-, 7-, or 8-position of 3-[3-(4-methoxyphenyl)-1-hydroxyprop-2-yl]coumarin on phytotoxicity

Derivatives of the coumarin ring in (R)-3-[3-(4-methoxyphenyl)-1-hydroxyprop-2-yl]coumarin 2, which is a lignan structure, were synthesized to clarify their structure-phytotoxicity relationships. The growth-inhibitory activity of the 8-OCH3 derivative 8 (IC50=228 µM) was more potent against the roots of lettuce seedlings than the compound without substituents 2. As for the roots of Italian ryegrass seedlings, the presence of the methoxy group at the 7- or 8-position was extremely effective for inhibiting growth (7-OCH3 7: IC50=121 µM, 8-OCH3 8: 56.7 µM). Methyl derivatives at the 5- or 8-position showed activity levels similar to those of the compound without substituents 2 (5-CH3 13: IC50=214 µM, 8-CH3 16: IC50=225 µM). The activities of OH- and F-derivatives were not observed or were lower.

Syntheses of Tetrahydropyran Type 8,7'-Neolignans Using a Ring-Expansion Reaction and Tetrahydrofuran Type 8,7'-Neolignans to Discover a Novel Phytotoxic Neolignan

One novel tri-substituted tetrahydropyran type 8,7'-neolignan and its enantiomer with higher enantiomeric excess were synthesized from all cis-tetra-substituted tetrahydrofuran with an iodomethyl group by a hydride or H2 ring-expansion reaction. The normal hydride reductions of C-I bonds of tetra-substituted tetrahydrofurans bearing iodomethyl groups were observed in other 2,3-cis-stereoisomers of tetra-substituted tetrahydrofurans to give tetra-substituted tetrahydrofurans bearing 7,8-cis and 8,7'-neolignan structures. The phytotoxicities of their synthesized compounds were compared with previously synthesized 7,8-trans-8,7'-neolignans bearing tetra-substituted tetrahydrofurans to find out the highest phytotoxic tri-substituted tetrahydropyran type 8,7'-neolignan.

Vascular Normalization Caused by Short-Term Lenvatinib Could Enhance Transarterial Chemoembolization in Hepatocellular Carcinoma

We describe the clinical effects of short-term lenvatinib administration prior to conventional transarterial chemoembolization (cTACE) on tumor vasculature. Two patients with unresectable hepatocellular carcinoma underwent high-resolution digital subtraction angiography (DSA) and perfusion four-dimensional computed tomography during hepatic arteriography (4D-CTHA) before and after administration of lenvatinib treatment. The doses and periods of lenvatinib administration were, respectively, 12 mg/day for 7 days and 8 mg/day for 4 days. In both cases, high-resolution DSA revealed a decrease in dilatation and tortuosity of the tumor vessels. Furthermore, the tumor staining became more refined, and newly formed tiny tumor vessels were observed. Perfusion 4D-CTHA revealed a decrease in arterial blood flow to the tumor by 28.6% (from 487.9 to 139.5 mL/min/100 mg) and 42.5% (from 288.2 to 122.6 mL/min/100 mg) in the two cases, respectively. The cTACE procedure resulted in good lipiodol accumulation and complete response. Patients have remained recurrence-free for 12 and 11 months after the cTACE procedure, respectively. The administration of short-term lenvatinib in these two cases resulted in the normalization of tumor vessels, which likely led to improved lipiodol accumulation and a favorable antitumor effect.

Regiospecific and Enantiospecific Effects of the β-Benzyl-α-benzylidene-γ-butyrolactone Structure on Phytotoxic Fungi

Novel derivatives of E-β-benzyl-α-benzylidene-γ-butyrolactone (3-benzyl-2-benzylidene-4-butanolide) with lignano-9,9'-lactone structures were developed as anti-phytopathogenic fungal compounds. Their regiospecific and enantiospecific characteristics were determined, with the E-form and 3R-configuration showing higher activities against the Alternaria alternata Japanese pear pathotype. By the syntheses of benzyl compounds instead of benzylidene and aromatic derivatives, followed by an bioassay experiment, the importance of the benzylidene structure and effects of the substituents of the aromatic ring were clarified. The (2-OCH₃, 4'-CH₃/4'-CF₃)-derivatives, 19 and 25, and (2-OCH₃, 6-CH₃/6-F/6-Br, 4'-OCH₃)-derivatives, 34, 38, and 42, were more effective with EC₅₀ values of 0.1-0.3 μM. It was assumed that the 2-OCH₃ group, a hydrophobic group at the 6-position, and some size of the hydrophobic group at the 4'-position were necessary for the increased activity.

Plant Growth Suppressive Activity of (R)-3-(7'-Aryl-9'-hydroxyprop-8'-yl)coumarin, Structural Isomer of Z-2-Hydroxybenzylidene-γ-butyrolactone-type Lignan

3-(7'-Aryl-9'-hydroxyprop-8'-yl)coumarin, which is a structural isomer of a Z-2-hydroxybenzylidene-γ-butyrolactone-type lignan, was stereoselectively synthesized and subjected to plant growth regulation examination. (R)-4'-Methoxyphenyl derivative 3 showed stereospecific plant growth suppressive activity. The significance of the presence of hydroxy group at the 9'-position for the activity was clarified. The effect of the substituent at the 7'-aryl group was also shown. The 3'-methoxy, 4'-methoxy, and 4'-trifluoromethyl derivatives 10, 3, and 22 led to the most significant growth suppression of Italian ryegrass roots. The 2'-methoxy derivative 9 and 4'-methoxy derivative 3 provided the most growth suppressive activity against lettuce shoots and roots, respectively.

Re-examination of Peptide-Sequence-Dependent Gene Expression of Cysteine-Installed Pegylated Oligolysine/DNA Complexes

We previously synthesized cysteine-installed C-terminally PEGylated oligolysines with 20 amino acid residues to form cross-linked polymeric micelles (PMs) with luciferase-coding plasmid DNA as a candidate for artificial gene vectors. Luciferase gene expression in HeLa cells mediated by PEG-CK₁₈C, PEG-CK₉CK₉, and PEG-K₉CK₉C was reported to be 35-, 5.4-, and 1.3-fold higher than that mediated by cysteine-uninstalled PEGylated oligolysine PEG-K₂₀, respectively. However, after the publication, the survival rate of HeLa cells used in the previous study was found to be lower than usual when subcutaneously implanted into mice to create a xenograft model. In this study, to re-examine the peptide sequence-dependent gene expression, gene expression efficacy mediated by PEG-peptide PMs was compared with the PM cellular uptake results using newly obtained HeLa cell lines and the additional cell lines Huh-7, PANC-1, and BxPC3. As a result, PEG-K₉CK₉C PMs mediated the maximum gene expression in all cell lines, and the corresponding cellular uptake was also obtained. Therefore, we concluded that our previous results were erroneously obtained due to normality-depleted HeLa cells. A comparison of physicochemical characterizations, gene expression efficacy, and cellular uptake of PEG-peptide PMs is discussed in detail.

Germination Stimulant Activity of Isothiocyanates on Phelipanche spp

The root parasitic weed broomrapes, Phelipanche spp., cause severe damage to agriculture all over the world. They have a special host-dependent lifecycle and their seeds can germinate only when they receive chemical signals released from host roots. Our previous study demonstrated that 2-phenylethyl isothiocyanate is an active germination stimulant for P. ramosa in root exudates of oilseed rape. In the present study, 21 commercially available ITCs were examined for P. ramosa seed germination stimulation, and some important structural features of ITCs for exhibiting P. ramosa seed germination stimulation have been uncovered. Structural optimization of ITC for germination stimulation resulted in ITCs that are highly active to P. ramosa. Interestingly, these ITCs induced germination of P. aegyptiaca but not Orobanche minor or Striga hermonthica. P. aegyptiaca seeds collected from mature plants parasitizing different hosts responded to these ITCs with different levels of sensitivity. ITCs have the potential to be used as inducers of suicidal germination of Phelipanche seeds.

Structure-activity relationship of the aromatic moiety of 6-substituted 5,6-dihydro-2H-pyran-2-one to find the novel compound showing higher plant growth inhibitory activity

In the course of our research on the structure-activity relationship of 5,6-dihydro-2H-pyran-2-one, (S)-6-[(R)-2-hydroxy-6-(4-fluorophenyl)hexyl]-5,6-dihydro-2H-pyran-2-one was found to show 2-3-fold more potent plant growth inhibitory activity against Italian ryegrass shoots (IC50 = 95 µm) and roots (IC50 = 17 µm) than compound bearing unsubstituted phenyl group. The small and electron withdrawing atom at 4-position of the benzene ring caused the higher activity.

A new species of Pseudasphondylia (Diptera: Cecidomyiidae) associated with Magnolia kobus DC. var. borealis Sarg. (Magnoliaceae) in Japan

Background

A gall midge species (Diptera: Cecidomyiidae) inducing leaf bud galls on MagnoliakobusDC.var.borealis Sarg. (Magnoliaceae) was found in Hokkaido and northern Honshu, Japan.

New information

Based on its morphology, the species is regarded as an undescribed species of the genus Pseudasphondylia Monzen (Cecidomyiinae, Cecidomyiidi, Asphondyliini). The species is herein described as Pseudasphondyliasaohimea Matsuda, Elsayed and Tokuda sp. n. The new species is easily distinguishable from its congeners by the number of adult palpal segments and the shape of the male terminalia and larval spatula.

Stereocontrolled syntheses of (-)- and (+)-γ-diisoeugenol along with optically active eight stereoisomers of 7,8'-epoxy-8,7'-neolignan

It was shown that reduction of the tertiary benzylic hydroxy group of (2R,3S,4R,5S)-3,5-bis(4-benzyloxy-3-methoxyphenyl)-2,4-dimethyltetrahydro-3-furanol 17 followed by the intramolecular Friedel-Crafts reaction gave exclusively indane with (7S,7'S,8R,8'R)-2,7'-cyclo-7,8'-neolignan structure 18 along with (7S,7'R,8S,8'R)-7,8'-epoxy-8,7'-neolignan structure 19. Indane 18 was converted to (-)-γ-diisoeugenol ((-)-4). On the other hand, (2S,3R,4R,5S)-3,5-bis(4-benzyloxy-3-methoxyphenyl)-2,4-dimethyltetrahydro-3-furanol 22 did not afford indane, but the tetrahydrofuran structure with (7S,7'S,8S,8'S)-7,8'-epoxy-8,7'-neolignan structure 23 and 7'-epi-23.

Impact of radial compression protocols on the compression time and radial artery occlusion

Background

Trans-radial access (TRA) has been established as a safe and established approach for invasive coronary catheter procedures. However, protocols for post-procedural hemostasis varies depending on institutes and an evidence-based protocol is lacking.

Purpose

The objective of this study was to investigate the clinical implications of procedural hemostasis.

Methods

Consecutive patients who were referred to outpatient catheter examination before and after April 2018 were treated with an old and a new protocol, respectively. In both protocols, we used the same commercially available hemostasis band with injecting an air of 16 ml for hemostasis. In the old protocol, the amount and timing of deflation were fixed, whereas the air was removed as much as possible for every 30 minutes in the new protocol. Time to complete hemostasis, the rate of major bleeding, and the rate of radial artery occlusion (RAO) at 6 months after the catheter examination were compared between the protocols.

Results

Total of 1,843 (71±10 years old, 77% male) patients was included in the study. Between patients in the old and the new protocol group (n=1,000 and 843, respectively), there was no significant difference in age, gender, body size, or systolic blood pressure. The new group had significantly higher prevalence of diabetes (47% vs 39%, p=0.002), slightly larger sheath size (4.1±0.3 vs 4.0±0.2 Fr, p&lt;0.001), and lower rate of dual antiplatelet therapy (DAPT: 24% vs. 35%, p&lt;0.001). Time for complete hemostasis was about one-third with the new protocol compared with the old protocol (65±32 vs. 190±16 min, p&lt;0.001) and there was no major bleeding in either group. The rate of radial artery occlusion was 0.7% and 9.8% in the old and the new group (p&lt;0.001). Multivariate analysis showed that the significant predictor of prolonged hemostasis time were the old protocol (odds ratio: OR 80.5, p&lt;0.001) and the prescription of DAPT (OR 2.9, p&lt;0.001), while the factors associated with higher risk of radial occlusion were the old protocol (OR 13.9, p&lt;0.001), the number of previous TRA (OR 1.1, p&lt;0.001), and smaller body size (OR 0.127 per 1 m2 increase p=0.005).

Conclusions

Our new protocol for hemostasis after TRA was strongly associated with shorter hemostasis time and a lower rate of radial artery occlusion. This approach will decrease the post-procedural hospital time with even fewer complication rates.

Study outline

Funding Acknowledgement

Type of funding source: None

Uterine adenomatoid tumor associated with lymph node lesions: a case report

We report a case of uterine adenomatoid tumor (AT) with regional lymph node involvement in a 49-year-old woman. Magnetic resonance imaging revealed an aggregated cystic mass in the posterior uterine wall with partial protrusion of the tumor outside the uterus, and cystic masses of same characteristics in the bilateral obturator and right common iliac lymph nodes. FDG PET/CT revealed no significant FDG uptake in the uterine and lymph node lesions. Taking possible lymph node metastasis into consideration, hysterectomy and lymph node biopsy were performed and it revealed AT of the uterus and the lymph nodes histopathologically.

Syntheses of all eight stereoisomers of conidendrin

All eight stereoisomers of conidendrin were synthesized from (1 R,2 S,3 S)-1-(4-benzyloxy-3-methoxyphenyl)-3-(4-benzyloxy-3-methoxybenzyl)-2- hydroxymethyl-1,4-butanediol ((+)-4) and its enantiomer with high optical purity. The configurations at 4-positions of the conidendrin stereoisomers were constructed by intramolecular Friedel-Crafts reaction of protected 4. After conversion to tetrahydronaphthalene intermediate 7a, the 2- and 3-position of tetrahydronaphthalene structure 7a were converted to 3a- and 9a-position of (+)-α-conidendrin (3a), respectively. By the epimerization process of 2- or 3-position of 7a, the other diastereomers were obtained. All enantiomers were also synthesized from (-)-4.

Hydroxyl carlactone derivatives are predominant strigolactones in Arabidopsis

Strigolactones (SLs) regulate important aspects of plant growth and stress responses. Many diverse types of SL occur in plants, but a complete picture of biosynthesis remains unclear. In Arabidopsis thaliana, we have demonstrated that MAX1, a cytochrome P450 monooxygenase, converts carlactone (CL) into carlactonoic acid (CLA) and that LBO, a 2-oxoglutarate-dependent dioxygenase, can convert methyl carlactonoate (MeCLA) into a metabolite called [MeCLA + 16 Da]. In the present study, feeding experiments with deuterated MeCLAs revealed that [MeCLA + 16 Da] is hydroxymethyl carlactonoate (1'-HO-MeCLA). Importantly, this LBO metabolite was detected in plants. Interestingly, other related compounds, methyl 4-hydroxycarlactonoate (4-HO-MeCLA) and methyl 16-hydroxycarlactonoate (16-HO-MeCLA), were also found to accumulate in lbo mutants. 3-HO-, 4-HO-, and 16-HO-CL were detected in plants, but their expected corresponding metabolites, HO-CLAs, were absent in max1 mutants. These results suggest that HO-CL derivatives may be predominant SLs in Arabidopsis, produced through MAX1 and LBO.

Effect of high ligation on survival of patients undergoing surgery for primary colorectal cancer and synchronous liver metastases

Background

Although R0 surgery is recommended for stage IV colorectal cancer, the degree of required lymphadenectomy has not been established. The aim of this study was to investigate the prognostic impact of high ligation (HL) of the feeding artery and the number of retrieved lymph nodes after R0 surgery for colorectal cancer and synchronous colorectal cancer liver metastasis (CRLM).

Methods

This was a multi‐institutional retrospective analysis of patients with colorectal cancer and synchronous CRLM who had R0 surgery between January 1997 and December 2007. Clinical and pathological features were compared in patients who underwent HL and those who had a low ligation (LL). Kaplan–Meier analysis was performed to estimate the effect of HL on overall survival (OS). The impact of several risk factors on survival was analysed using the Cox proportional hazards model.

Results

Of 549 patients, 409 (74·5 per cent) had HL. Median follow‐up was 51·4 months. HL significantly improved the 5‐year OS rate (58·2 per cent versus 49·3 per cent for LL; P = 0·017). Multivariable analysis revealed HL to be a significant prognostic factor compared with LL (5‐year mortality: hazard ratio (HR) 0·68, 95 per cent c.i. 0·51 to 0·90; P = 0·007). In subgroup analysis, the positive effect of HL on OS was greatest in patients with lymph node metastasis.

Conclusion

HL of the feeding artery was associated with improved OS in patients with colorectal cancer and synchronous CRLM after R0 surgery.

High-Performance Dental Adhesives Containing an Ether-Based Monomer

Dental adhesives are vital for the success of dental restorations. The objective of this study is to make strong and durable dental adhesives that are free from 2 symbolic methacrylate-based dental resins-2-bis[4-(2-hydroxy-3-methacryl-oxypropoxy)-phenyl]-propane (Bis-GMA) and 2-hydroxyethyl-methacrylate (HEMA)-and have equivalent/improved bonding strength and durability. We formulated, prepared, and evaluated 2 dental adhesives using mixtures of a hydrolytically stable ether-based monomer, triethylene glycol divinylbenzyl ether (TEG-DVBE), with urethane dimethacrylate (UDMA) or pyromellitic glycerol dimethacrylate. These adhesives were composed of equimolar ester-/ether-based vinyl functional groups. They were compared with Bis-GMA/HEMA-based commercial and experimental dental adhesives in terms of shear bond strength and microtensile bond strength (µTBS) to human dentin and the µTBS bond stability under extended thermocycling challenges. In addition, the resins' infiltration to dentin tubules, mechanical performance, and chemical properties were assessed by scanning electron microscopy, ISO standard flexural strength and modulus measurements, contact angle measurements, and water sorption/solubility measurements. The hybrid TEG-DVBE-containing dental adhesives generated equivalent shear bond strength and µTBS in comparison with the controls. Significantly, these adhesives outperformed the controls after being challenged by 10,000 thermocycles between 5 °C and 55 °C. Water contact angle measurements suggested that the hybrid dental adhesives were relatively more hydrophobic than the Bis-GMA/HEMA controls. However, both TEG-DVBE-containing adhesives developed more and deeper resin tags in dentin tubules and formed thicker hybrid layers at the composite-dentin interface. Furthermore, the water solubility of UDMA/TEG-DVBE resins was reduced approximately 89% in comparison with the Bis-GMA/HEMA controls. The relatively hydrophobic adhesives that achieved equivalent/enhanced bonding performance suggest great potentials in developing dental restoration with extended service life. Furthermore, the TEG-DVBE-containing materials may find wider dental applications and broader utility in medical device development.

Syntheses and Phytotoxicity of All Stereoisomers of 6-(2-Hydroxy-6-phenylhex-1-yl)-5,6-dihydro-2H-pyran-2-one and Determination of the Effect of the α,β-Unsaturated Carbonyl Structure and Hydroxy Group Bonding to Chiral Carbon

All four stereoisomers of naturally occurring 6-(2-hydroxy-6-phenylhex-1-yl)-5,6-dihydro-2H-pyran-2-one (1) were synthesized by employing yeast-reduction products with high optical purity [from 95% enantiomeric excess (ee) to more than 99% ee], and then their phytotoxicities against lettuce and Italian ryegrass were evaluated. In the Italian ryegrass seedlings test, (6S,2'R)-1 showed the most potent and stereospecific activity against the shoots (IC50 = 260 μM) and roots (IC50 = 43.2 μM), with a significant difference from other stereoisomers. The highest seed germination inhibitory activity against Italian ryegrass seed was also observed in (6S,2'R)-1, showing a 53% germination ratio from the control at 1000 μM. This advantageous (6S,2'R) stereochemistry was employed in the syntheses of α,β-dihydro, 2'-dehydroxy, and 2'-methoxy derivatives 13-15. By the test using these derivatives, the importance of the α,β-unsaturated double bond and hydroxy group bonding to a chiral center on the 6-alkyl chain of 5,6-dihydro-α-pyrone for phytotoxicity was determined. In the test against lettuce, the 6S configuration and (6S,2'S) configuration were necessary for growth inhibition (IC50 = ca. 60 μM) and germination inhibition (63% germination ratio at 1000 μM), respectively.

Cytotoxicity against HL60 Cells of Ficifolidione Derivatives with Methyl, n-Pentyl, and n-Heptyl Groups

Ficifolidione, a natural insecticidal compound isolated from the essential oils of Myetaceae species, is a spiro phloroglucinol with an isobutyl group at the C-4 position. We found that ficifolidione showed cytotoxicity against cancer cells via apoptosis. Replacement of the isobutyl group by n-propyl group did not influence the potency, but the effect of the replacement of this group by a shorter or longer alkyl group on the biological activity remains unknown. In this study, ficifolidione derivatives with alkyl groups such as methyl, n-pentyl, and n-heptyl group—instead of the isobutyl group at the C-4 position—were synthesized to evaluate their cytotoxicity against the human promyelocytic leukaemia cell line HL60 and their insecticidal activity against mosquito larvae. The biological activities of their corresponding 4-epimers were also evaluated. As a result, the conversion of the isobutyl group to another alkyl group did not significantly influence the cytotoxicity or insecticidal activity. In HL60 cells treated with the n-heptyl-ficifolidione derivative, the activation of caspase 3/7 and the early stages of apoptosis were detected by using immunofluorescence and flow cytometric techniques, respectively, suggesting that the cytotoxicity should be induced by apoptosis even though the alkyl group was changed.