著者
Shimba Kawasue Yohei Sakaguchi Reiko Koga Tadashi Hayama Hideyuki Yoshida Hitoshi Nohta
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.70, no.1, pp.19-24, 2022-01-01 (Released:2022-01-01)
参考文献数
30

Casein is one of the allergen proteins present in milk. Therefore, a quantification method for the selective analysis of casein using fluorous derivatization with LC-tandem mass spectrometry (LC-MS/MS) was developed. After two allergen proteins (αS1-casein and β-casein) extracted from baked sugar cookies were tryptic digested, the obtained phosphorylated peptides were selectively derivatized by β-elimination with Ba(NO3)2 under basic condition and Michael addition with perfluoroalkylthiol (1H,1H,2H,2H-perfluorooctanethiol, PFOT). In this study, YKVPQLEIVPN(pSer)AQQR (104–119 fragment from αS1-casein) and FQ(pSer)EEQQQTEDELQDK (33–48 fragment from β-casein) obtained by tryptic digestion were selected as target peptides. The phosphorylated serine residue in each peptide was converted to a perfluoroalkyl group by derivatization. The obtained fluorous-derivatized peptides were analyzed by LC-MS/MS, to which a fluorous LC column was connected. Therefore, it was possible to analyze casein without being affected by the matrix components in the baked food sample. When the present method was applied to cookies with arbitrary amounts of αS1-casein and β-casein, the obtained quantification values were in good agreement with the arbitrary amounts spiked. The quantification limits of αS1- and β-casein in cookie analysis were 246 and 152 ng/g, respectively. Hence, this method can be used to analyze trace amounts of allergen proteins present in the baked food.
著者
Yoshio Muguruma Mari Nunome Koichi Inoue
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.70, no.1, pp.12-18, 2022-01-01 (Released:2022-01-01)
参考文献数
93
被引用文献数
8

Due to the globalization of food production and distribution, the food chain has become increasingly complex, making it more difficult to evaluate unexpected food changes. Therefore, establishing sensitive, robust, and cost-effective analytical platforms to efficiently extract and analyze the food-chemicals in complex food matrices is essential, however, challenging. LC/MS-based metabolomics is the key to obtain a broad overview of human metabolism and understand novel food science. Various metabolomics approaches (e.g., targeted and/or untargeted) and sample preparation techniques in food analysis have their own advantages and limitations. Selecting an analytical platform that matches the characteristics of the analytes is important for food analysis. This review highlighted the recent trends and applications of metabolomics based on “foodomics” by LC-MS and provides the perspectives and insights into the methodology and various sample preparation techniques in food analysis.
著者
Taichi Kamo Keiichi Kuroda Shota Kondo Usaki Hayashi Satoshi Fudo Tomoki Yoneda Akiko Takaya Michiyoshi Nukaga Tyuji Hoshino
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.69, no.12, pp.1179-1183, 2021-12-01 (Released:2021-12-01)
参考文献数
29
被引用文献数
2

Metallo-β-lactamases (MBLs) are significant threats to humans because they deteriorate many kinds of β-lactam antibiotics and are key enzymes responsible for multi-drug resistance of bacterial pathogens. As a result of in vitro screening, two compounds were identified as potent inhibitors of two kinds of MBLs: imipenemase (IMP-1) and New Delhi metallo-β-lactamase (NDM-1). The binding structure of one of the identified compounds was clarified by an X-ray crystal analysis in complex with IMP-1, in which two possible binding poses were observed. Molecular dynamics (MD) simulations were performed by building two calculation models from the respective binding poses. The compound was stably bound to the catalytic site during the simulation in one pose. The binding model between NDM-1 and the compound was constructed for MD simulation. Calculation results for NDM-1 were similar to those of IMP-1. The simulation suggested that the binding of the identified inhibitory compound was also durable in the catalytic site of NDM-1. The compound will be a sound basis for the development of the inhibitors for MBLs.
著者
阿部 フミ子 山内 辰郎
出版者
公益社団法人日本薬学会
雑誌
Chemical & pharmaceutical bulletin (ISSN:00092363)
巻号頁・発行日
vol.25, no.10, pp.2744-2748, 1977-10-25

Cardenolides in the seeds, bark, and leaves of Cerbera manghas L. were investigated. From the seeds, tanghinigenin glycosides were isolated along with known digitoxigenin glycosides, cerberin, neriifolin, thevetin B, and 2'-O-acetyl thevetin B. From the barks of root and stem, gentiobiosyl thevetoside, glucosyl thevetoside, and thevetoside of tanghinigenin and 17βH-tanghinigenin were obtained. The cardenolides in the air-dried leaves were found to vary with seasons. 17βH-neriifolin is major and preferable to neriifolin in July, while 17βH-deacetyltanghinin and deacetyltanghinin present in the leaves of Feb.
著者
Hiroshi Tateishi Mika Tateishi Mohamed O Radwan Takuya Masunaga Kosuke Kawatashiro Yasunori Oba Misato Oyama Natsuki Inoue-Kitahashi Mikako Fujita Yoshinari Okamoto Masami Otsuka
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.69, no.11, pp.1123-1130, 2021-11-01 (Released:2021-11-01)
参考文献数
41
被引用文献数
11

A disintegrin and metalloproteinase 17 (ADAM17) is a zinc-dependent enzyme that catalyzes the cleavage of the extracellular domains of various transmembrane proteins. ADAM17 is regarded as a promising drug target for the suppression of various diseases, including cancer metastasis. We synthesized a new ADAM17 inhibitor, SN-4, composed of a zinc-binding dithiol moiety and an appendage that specifically binds to a pocket of ADAM17. We show that SN-4 inhibits the ability of ADAM17 to cleave tumor necrosis factor α (TNF-α) in vitro. This activity was reduced by the addition of zinc, indicating the importance of the zinc chelating dithiol moiety. Inhibition of TNF-α cleavage by SN-4 in cells was also observed, and with an IC50 of 3.22 µM, SN-4 showed slightly higher activity than the well-studied ADAM17 inhibitor marimastat. Furthermore, SN-4 was shown to inhibit cleavage of CD44 by ADAM17, but not by ADAM10, and to suppress cell invasion. Molecular docking showed good fitting of the specificity pocket-binding group and one SH of SN-4 and hinted at possible means of structural optimization. This study provides clues for the development of potent and selective ADAM17 inhibitors.
著者
Yuqin Zhou Weitong Hu Xiangli Zhang Yi Wang Wenya Zhuang Fengzhi Li Qingyong Li
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.69, no.11, pp.1054-1060, 2021-11-01 (Released:2021-11-01)
参考文献数
42
被引用文献数
9

In the evaluation of the druggability of candidate compounds, it was vital to predict the oral bioavailability of compounds from apparent permeability (Papp) across Caco-2 cell-culture model of intestinal epithelium cultured on commercial transwell plate inserts. The study was to investigate the transport characteristics and permeability of FL118 (10, 11-Methylenedioxy-20(S)-camptothecin) derivatives 7-Q6 (7-(4-Ethylphenyl)-10, 11-methylenedioxy-20(S)-camptothecin) and 7-Q20 (7-(4-Trifluoromethylphenyl)-10, 11-methylenedioxy-20(S)-camptothecin). Transport characteristics and permeability of the tested compounds to the small intestine were assessed at different concentrations (0.5, 1 µM) via Caco-2 cell monolayers model in vitro. Uptake studies based on Caco-2 cells, including temperatures, concentrations, and the influence of efflux transporters, were combined to confirm the transport characteristics of the tested compounds. Furthermore, cytotoxicity results showed that the concentrations used in the experiments were non-toxic and harmless to cells. In addition, The Papp of 7-Q6 was (3.69 ± 1.07) × 10−6 cm/s with efflux ratio (ER) 0.98, while the Papp of 7-Q20 was (7.78 ± 0.89) × 10−6 cm/s with ER 1.05 for apical-to-basolateral (AP→BL) at 0.5 µM, suggesting that 7-Q20 might possess higher oral bioavailability in vivo. Furthermore, P-glycoprotein (P-gp) was proved to slightly affect the accumulations of 7-Q20, while the absorption of 7-Q6 was irrelevant with P-gp and breast cancer resistant protein (BCRP) based on the cellular uptake assays. Accordingly, 7-Q6 was completely absorbed by passive diffusion, and 7-Q20 was mainly dependent on passive diffusion with being effluxed by P-gp slightly. Meanwhile, both 7-Q6 and 7-Q20 were potential antitumor drugs that might exhibit high oral bioavailability in the body.
著者
Masahiro Ueda Chiaki Komiya Sayuki Arii Kohshi Kusumoto Masaya Denda Keiichiro Okuhira Akira Shigenaga Akira Otaka
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.68, no.12, pp.1226-1232, 2020-12-01 (Released:2020-12-01)
参考文献数
26
被引用文献数
1 4

Proteins incorporating artificial moieties such as fluorophores and drugs have enjoyed increasing use in chemical biology and drug development research. Preparation of such artificial protein derivatives has relied mainly on native chemical ligation in which peptide/protein thioesters chemoselectively react with N-terminal cysteine (Cys) peptides to afford protein molecules. The protein thioesters derived from expressed proteins represent thioesters that are very useful for the preparation of artificial proteins by native chemical ligation with synthetic peptides with N-terminal Cys. We recently have developed a traceless thioester-producing protocol using carboxypeptidase Y (CPaseY) which is compatible with an expressed protein. The traceless character is ensured by CPaseY-mediated hydrazinolysis of C-terminal Xaa (X)-Cys-proline (Pro)-leucine (Leu)-OH sequence followed by an auto-processing of the Cys-Pro (CP) dipeptide unit, affording the corresponding X-thioester (X-SR). However, hydrazinolysis of the amide bond in the prolyl leucine junction depends significantly on the nature of X. In the case of hydrophobic X residues, the hydrazinolysis overreacts to give several hydrazides while the reaction of hydrophilic X residues proceeds slowly. In this research, we attempted to develop an X-independent CPaseY-mediated protocol and found that the incorporation of a triple CP sequence into the C-terminal end (X-(CP)3-Leu-OH) allows for efficient X-SR formation in a manner that is independent of X.
著者
Yutaka Matsuda Brian A. Mendelsohn
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.69, no.10, pp.976-983, 2021-10-01 (Released:2021-10-01)
参考文献数
78
被引用文献数
26

Antibody–drug conjugates (ADCs) are biopharmaceuticals produced by chemically linking small molecules (payloads) to antibodies that possess specific affinity for the target cell. The ADCs currently on the commercially market are the result of a stochastic conjugation of highly-potent payloads to multiple sites on the monoclonal antibody, resulting in a heterogeneous drug–antibody ratio (DAR) and drug distribution. The heterogeneity inherent to ADCs not produced site-specifically may not only be detrimental to the quality of the drug but also is less-desirable from the perspective of regulatory science. An ideal method or unified approach used to measure the DAR for ADCs, a critical aspect of their analysis and characterization, has not yet been established in the ADC field and remains an often-challenging issue for bioanalytical chemists. In this review we describe, compare, and evaluate the characteristics of various DAR determination methods for ADCs featuring recently reported technologies. The future landscape of bioconjugate DAR analysis is also discussed.
著者
Toshinari Suzuki Yuki Kosugi Kimiyo Watanabe Haruka Iida Tetsuji Nishimura
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.69, no.9, pp.840-853, 2021-09-01 (Released:2021-09-01)
参考文献数
70
被引用文献数
5

Active pharmaceutical ingredients (APIs) have become a public concern owing to their possible adverse effects on aquatic organisms. Ministry of Health, Labor and Welfare in Japan (MHLW) issued “Guidance on the Environmental Risk Assessment (ERA) in new pharmaceutical development” in 2016. To evaluate the validity of phase 1 in the MHLW’s ERA guidance, we monitored the measured environmental concentrations (MECs) of approved APIs in urban rivers and sewage treatment plants (STPs) in Japan and compared these MECs with the predicted environmental concentration (PEC). We collected water samples from urban seven rivers and three STPs during each season. Fifty-one APIs for human and veterinary use and the artificial sweetener sucralose were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Forty-four APIs were observed in the rivers and 42 were found in the influent and effluent of STPs, with levels ranging from nanograms to micrograms per liter. The action limit in phase I of the MHLW’s guidance was set to 10 ng/L, and there was no API except for ketoprofen, for which PEC of the MHLW’s guidance (PECjapan) was lower than 10 ng/L and the maximum MEC (MECmax) was 10 ng/L or greater. Almost all APIs also had median MECs that were lower than those of the respective PECjapan. These results indicate that the PECjapan values in phase I of the MHLW’s guidance were appropriate. However, some APIs had MECmax values that were greater than those of the respective PECjapan due to overestimation of the dilution factor of river water and/or underestimation of API production.
著者
Alexandre Nesterov Jifu Zhao David Minter Carmen Hertel Wenwen Ma Padmapriya Abeysinghe Mei Hong Qi Jia
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.56, no.9, pp.1292-1296, 2008-09-01 (Released:2008-09-01)
参考文献数
23
被引用文献数
24 31

A series of diarylpropane compounds was isolated by screening a plant extract library for inhibitors of mushroom tyrosinase. The most potent compound, 1-(2,4-dihydroxyphenyl)-3-(2,4-dimethoxy-3-methylphenyl)propane (UP302: CAS# 869743-37-3), was found in the medicinal plant Dianella ensifolia. Synthetic and plant-derived versions of UP302 inhibited mushroom tyrosinase with similar potencies. UP302 inhibited mushroom tyrosinase with Ki=0.3 μM, in a competitive and reversible fashion. UP302 was 22 times more potent than Kojic acid in inhibiting murine tyrosinase, with IC50 values of 12 and 273 μM respectively. Experiments on mouse melanoma cells B16-F1 and on human primary melanocytes demonstrated that UP302 inhibits melanin formation with IC50 values of 15 and 8 μM respectively. Long-term treatment of cultured melanocytes with up to 62 μM of UP302 revealed no detectable cytotoxicity. In a reconstructed skin model (MelanoDermTM) topical application of 0.1% UP302 resulted in significant skin lightening and decrease of melanin production without effects on cell viability, melanocyte morphology or overall tissue histology. In conclusion, UP302 is a novel tyrosinase inhibitor that suppresses melanin production in both cultured melanocytes and reconstructed skin with high potency and without adverse side effects.
著者
小木曽 彰 佐藤 藹也 樫田 育子 杉村 征夫
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.22, no.1, pp.144-151, 1974-01-25 (Released:2008-03-31)
被引用文献数
1 3

A key point of the synthesis of aglycones (12 and 33) derived from poriolide (1) and isoporiolide (2), the toxic constituents of Leucothoe keiskei, is the construction of the unsymmetric biphenyl compounds, this point was effected by application of the rearrangement reaction of suitable phenyltropone derivatives to biphenyl compounds.
著者
Shiroh Futaki
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.69, no.7, pp.601-607, 2021-07-01 (Released:2021-07-01)
参考文献数
57
被引用文献数
10

Biomembranes are important targets in molecular design. Our laboratory has been exploring the design of functional peptides that modulate membrane barrier function, lipid packing, and structure. Evaluation of the results obtained and analyses of cellular mechanisms have yielded peptides with more refined designs and functions. This review highlights the progress made in our laboratory towards the development of unique peptides that modulate membrane properties.
著者
脇田 桂子 吉本 昌文 宮本 秀一 渡辺 英俊
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.34, no.11, pp.4663-4681, 1986-11-25 (Released:2008-03-31)
参考文献数
14
被引用文献数
46 62

For the calculation of the aqueous solubility of organic compounds, we defined new fragment solubility constants (fs) which were empirically determined on the basis of compiled data from the literature. First, 6 fundamental fs values were determined from data on 46 liquid alliphatic hydrocarbons. THese fs values were fixed, and data on 249 liquid aliphatic compounds with diverse functional groups were employed to optimize another 19 fs values of the groups. Then, 15 fs values of aromatic compounds were calculated based on the solubility data on 58 aromatic liquids and the aliphatic fs values.It has been shown that there is a linear relationship between the logarithims of the aqueous solubilities of organic liquids and the octanol-water partition constants (log P), and that the water solubilities can be calculated by using the correlation equation and log P values. The present paper is concerned with a method to calculate the aqueous solubilities of organic liquids simply, directly and more accurately on the basis of fs values. Furthermore, the calculation of the water solubilities of organic solids was attempted with a correction based on the melting points, in addition to using the fs values.
著者
Chung-Yi Lo Hsueh-Ling Cheng Jue-Liang Hsu Ming-Hui Liao Rong-Lang Yen Yo-Chia Chen
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.61, no.6, pp.604-610, 2013-06-01 (Released:2013-06-01)
参考文献数
28
被引用文献数
2 3

Three phenyl derivatives of butyrate, 2-phenylbutyrate (2-PB), 3-phenylbutyrate (3-PB) and 4-phenylbutyrate (4-PB), were evaluated in terms of their antibacterial and cytotoxic activities. Our results indicated that PBs demonstrated specific inhibitory activity against Helicobacter pylori and Escherichia coli but did not influence the growth of Bifidobacterium bifidium and Lactobacillus reuteri. PBs also exhibited synergistic effects on H. pylori ATCC 43504 especially at pH 5.5. In the protein expression profiles in H. pylori treated by phenylbutyrates, we also found that three protein spots identified as oxidative stress-related proteins were significantly up-regulated, confirming the response of H. pylori when exposed to PBs. Due to their antibacterial activities and low or slight cytotoxicities, PBs are potential candidates for the treatment of H. pylori infection. This is the first study to discover the antibiotic effects of 2-PB, 3-PB and 4-PB (Buphenyl).
著者
Tassadit Belabbas Takaaki Yamada Yuichi Tsuchiya Kimitaka Suetsugu Nobuaki Egashira Ichiro Ieiri
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.69, no.7, pp.646-651, 2021-07-01 (Released:2021-07-01)
参考文献数
17
被引用文献数
2

With the aim of studying the pharmacokinetics of letermovir, which is a newly developed antiviral agent for human cytomegalovirus, a rapid and simple ultra-performance liquid chromatography coupled with mass spectrometry (UPLC/MS) method was developed and validated for the quantification of letermovir in human plasma. Separation was performed in reverse phase mode using an ACQUITY UPLC BEH C18 column (130 Å, 1.7 µm, 2.1 × 50 mm) at a flow rate of 0.3 mL/min, 10 mM ammonium acetate–0.1% formic acid solution as mobile phase A, and acetonitrile as mobile phase B with a gradient elution. The method was validated over a linear range of 10–1000 ng/mL with a coefficient of determination (R2) >0.99 using weighted linear regression analysis. The intra- and inter-assay accuracy (nominal%) and precision (relative standard deviation%) were within ±15 and ≤15%, respectively. The specificity, recovery, matrix effect, stability, and dilution integrity of this method were also within acceptable limits. This method could be useful in studying the pharmacokinetics and pharmacodynamics, as well as performing the therapeutic drug monitoring of letermovir.
著者
Midori A. Arai
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.69, no.6, pp.503-515, 2021-06-01 (Released:2021-06-01)
参考文献数
29
被引用文献数
1

Natural products are very attractive for development of medicine. Their structure and bioactivities are often beyond human knowledge and imagination. We have developed isolation methods for target protein-oriented natural products so as quickly to discover bioactive compounds from natural resources. This review summarizes our recent results including protein beads methods for neural stem cells differentiation activators and new cancer drug candidates. Syntheses of isolated compounds are described. We also developed protein plate method for identification of protein–protein interaction inhibitors. Because protein binding ability is tightly related to bioactivity, protein-based natural products isolation is a powerful means to find new candidate medicines.
著者
Ryo Yazaki
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.69, no.6, pp.516-525, 2021-06-01 (Released:2021-06-01)
参考文献数
88
被引用文献数
5

Catalytic chemoselective reactions of innately less reactive functionalities over more reactive functionalities are described. A cooperative catalyst comprising a soft Lewis acid/hard Brønsted base enabled chemoselective activation of a hydroxyl group over an amino group, allowing for nucleophilic addition to electron-deficient olefins. The reaction could be applicable for a variety of amino alcohols, including pharmaceuticals, without requiring a tedious protection–deprotection process. Chemoselective enolization and subsequent α-functionalization of carboxylic acid derivatives were also achieved by a redox active catalyst through the radical process, providing unnatural α-amino/hydroxy acid derivatives bearing a complex carbon framework and a diverse set of functionalities. The present chemoselective catalysis described herein offers new opportunities to expand the chemical space for innovative drug discovery research.
著者
Takashi Tsujimoto Ryoko Arai Taichi Yoshitomi Yutaka Yamamoto Yoshihiro Ozeki Takashi Hakamatsuka Nahoko Uchiyama
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
pp.c21-00180, (Released:2021-05-21)
参考文献数
19
被引用文献数
9

Citrus-type crude drugs (CCDs) are commonly used to formulate decoctions in Kampo formula (traditional Japanese medicine). Our previous study reported metabolomic analyses for differentiation of the methanol extracts of Citrus-type crude drugs (CCDs) using UHPLC/MS, and 13C- and 1H-NMR. The present study expanded the scope of its application by analyzing four CCD water extracts (Kijitsu, Tohi, Chimpi, and Kippi); these CCDs are usually used as decoction ingredients in the Kampo formula. A principal component analysis score plot of processed UPLC/MS and NMR analysis data indicated that the CCD water extracts could be classified into three groups. The loading plots showed that naringin and neohesperidin were the distinguishing components. Three primary metabolites, α-glucose, β-glucose, and sucrose were identified as distinguishing compounds by NMR spectroscopy. During the preparation of CCD dry extracts, some compounds volatilized or decomposed. Consequently, fewer compounds were detected than in our previous studies using methanol extract. However, these results suggested that the combined NMR- and LC/MS-based metabolomics can discriminate crude drugs in dried water extracts of CCDs.
著者
柏田 良樹 森田 益史 野中 源一郎 西岡 五夫
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.38, no.4, pp.856-860, 1990-04-25 (Released:2008-03-31)
参考文献数
13
被引用文献数
11 15

A chemical examination of the polyphenolic constituents of the fern, Dicranopteris pedata HOUTT., has led to the isolation of eight new proanthocyanidins possessing a doubly-linked (A-type) unit, together with known flavan-3-ols and proanthocyanidins. On the basis of chemical and spectroscopic evidence, they are characterized as epiafzelechin-(4β→8, 2β→O→7)-eniafzelechin-(4α→8)-epiafzelechin(8), epicatechin-(4β→8, 2β→O→7)-epiafzelechin-(4α→8)-epiafzelechin(9), epiafzelechin-(4β→8, 2β→O→7)-epizfzelechin-(4α→8)-epicatechin(10), epiafzelechin-(4β→8, 2β→O→7)-epicatechin-(4α→8)-epicatechin (11), epicatechin-(4β→8, 2β→O→7)-epiafzelechin-(4α→8)-epicatechin (12), epicatechin-(4β→8, 2β→O→7)-epicatechin-(4α→8)-epiafzelechin (13), epicatechin-(4β→8, 2β→O→7)-epicatechin-(4α→8)-epigallocatechin (14) and epiafzelechin-(4β→8)epicatechin-(4β→8, 2β→O→β→7)-epicatechin-(4α→8)-epicatechin (15).