著者
Congyun Jin Yoshiaki Yao Atsushi Yonezawa Satoshi Imai Hiroki Yoshimatsu Yuki Otani Tomohiro Omura Shunsaku Nakagawa Takayuki Nakagawa Kazuo Matsubara
出版者
The Pharmaceutical Society of Japan
雑誌
Biological and Pharmaceutical Bulletin (ISSN:09186158)
巻号頁・発行日
vol.40, no.11, pp.1990-1995, 2017-11-01 (Released:2017-11-01)
参考文献数
22
被引用文献数
13

Riboflavin (vitamin B2) plays a role in various biochemical oxidation-reduction reactions. Flavin mononucleotide (FMN) and FAD, the biologically active forms, are made from riboflavin. Riboflavin transporters (RFVTs), RFVT1-3/Slc52a1-3, have been identified. However, the roles of human (h)RFVTs in FMN and FAD homeostasis have not yet been fully clarified. In this study, we assessed the contribution of each hRFVT to riboflavin, FMN and FAD uptake and efflux using in vitro studies. The transfection of hRFVTs increased cellular riboflavin concentrations. The uptake of riboflavin by human embryonic kidney cells transfected with hRFVTs was significantly increased, and the efflux was accelerated in a time-dependent manner. However, the uptake and efflux of FMN and FAD hardly changed. These results strongly suggest that riboflavin, rather than FMN or FAD, passes through plasma membranes via hRFVTs. Our findings could suggest that hRFVTs are involved in riboflavin homeostasis in the cells, and that FMN and FAD concentrations are regulated by riboflavin kinase and FAD synthase.
著者
Aurpita Shaha Hiroyuki Mizuguchi Yoshiaki Kitamura Hiromichi Fujino Masami Yabumoto Noriaki Takeda Hiroyuki Fukui
出版者
The Pharmaceutical Society of Japan
雑誌
Biological and Pharmaceutical Bulletin (ISSN:09186158)
巻号頁・発行日
vol.41, no.9, pp.1440-1447, 2018-09-01 (Released:2018-09-01)
参考文献数
44
被引用文献数
23

The significant correlation between nasal symptom scores and level of histamine H1 receptor (H1R) mRNA in nasal mucosa was observed in patients with pollinosis, suggesting that H1R gene is an allergic disease sensitive gene. We demonstrated that H1R and interleukin (IL)-9 gene are the allergic rhinitis (AR)-sensitive genes and protein kinase Cδ (PKCδ) signaling and nuclear factor of activated T-cells (NFAT) signaling are involved in their expressions, respectively. Honey bee products have been used to treat allergic diseases. However, their pathological mechanism remains to be elucidated. In the present study, we investigated the mechanism of the anti-allergic effect of royal jelly (RJ) and Brazilian green propolis (BGPP). Treatment with RJ and BGPP decreased in the number of sneezing on toluene 2,4-diissocyanate (TDI)-stimulated rats. The remarkable suppression of H1R mRNA in nasal mucosa was observed. RJ and BGPP also suppressed the expression of IL-9 gene. RJ and BGPP suppressed phorbol-12-myristate-13-acetate-induced Tyr311 phosphorylation of PKCδ in HeLa cells. In RBL-2H3 cells, RJ and BGPP also suppressed NFAT-mediated IL-9 gene expression. These results suggest that RJ and BGPP improve allergic symptoms by suppressing PKCδ and NFAT signaling pathways, two important signal pathways for the AR pathogenesis, and suggest that RJ and BGPP could be good therapeutics against AR.
著者
Jiangang Chen Wenfang Lu Hao Chen Xiaoli Bian Guangde Yang
出版者
The Pharmaceutical Society of Japan
雑誌
Biological and Pharmaceutical Bulletin (ISSN:09186158)
巻号頁・発行日
pp.b18-00661, (Released:2018-11-30)
参考文献数
40
被引用文献数
3 10

In this study, a series of salicylic acid derivatives were designed and synthesized as novel non-saccharide α-glucosidase inhibitors. Biological evaluation indicated that when compared to acarbose, compounds T9, T10, and T32 exhibited a higher potency of α-glucosidase inhibitory activity with IC50 values of 0.15 ± 0.01 mM, 0.086 ± 0.01 mM and 0.32 ± 0.02 mM, respectively. Evaluation of the inhibition kinetics indicated that T9, T10, T32, and acarbose interacted with α-glucosidase in a mixed non-competitive inhibitory manner. Moreover, T9, T10, and T32 statically quenched the fluorescence of α-glucosidase by formation of an inhibitor-α-glucosidase complex. The docking results showed that hydrogen bonds were generated between the test compounds and α-glucosidase. The antioxidant study revealed that compound T10 exhibited a higher antioxidant activity via scavenging 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH), thereby inhibiting lipid peroxidation and the total reduction capacity. In brief, the salicylic acid derivatives identified in this study were promising candidates for development as novel non-saccharide α-glucosidase inhibitors.
著者
Kosuke Baba Reiko Hiramatsu Benjamart Suradej Riho Tanigaki Sayaka Koeda Tomonori Waku Takao Kataoka
出版者
The Pharmaceutical Society of Japan
雑誌
Biological and Pharmaceutical Bulletin (ISSN:09186158)
巻号頁・発行日
vol.41, no.12, pp.1757-1768, 2018-12-01 (Released:2018-12-01)
参考文献数
45
被引用文献数
1 9

The pentacyclic triterpenoid ursolic acid was previously shown to inhibit the intracellular trafficking of intercellular adhesion molecule-1 (ICAM-1) from the endoplasmic reticulum (ER) to the Golgi apparatus. In the present study, we further investigated the biological activities of three pentacyclic triterpenoids closely related to ursolic acid on the interleukin 1α-induced expression and intracellular trafficking of ICAM-1. In human lung adenocarcinoma A549 cells, asiatic acid, corosolic acid, and maslinic acid interfered with the intracellular transport of ICAM-1 to the cell surface. Endoglycosidase H-sensitive glycans were linked to ICAM-1 in asiatic acid-, corosolic acid-, and maslinic acid-treated cells. Unlike corosolic acid, asiatic acid and maslinic acid increased the amount of the ICAM-1 protein. Moreover, asiatic acid increased the co-localization of ICAM-1 with calnexin (an ER marker), but not GM130 (a cis-Golgi marker). Asiatic acid, corosolic acid, and maslinic acid inhibited yeast α-glucosidase activity, but not Jack bean α-mannosidase activity. These results indicate that asiatic acid, corosolic acid, and maslinic acid interfere with the intracellular transport of ICAM-1 to the cell surface and cause the accumulation of ICAM-1 linked to endoglycosidase H-sensitive glycans.
著者
Takashi Yamauchi
出版者
The Pharmaceutical Society of Japan
雑誌
Biological and Pharmaceutical Bulletin (ISSN:09186158)
巻号頁・発行日
vol.28, no.8, pp.1342-1354, 2005 (Released:2005-08-01)
参考文献数
129
被引用文献数
112 153

Much has been learned about the activity-dependent synaptic modifications that are thought to underlie memory storage, but the mechanism by which these modifications are stored remains unclear. A good candidate for the storage mechanism is Ca2+/calmodulin-dependent protein kinase II (CaM kinase II). CaM kinase II is one of the most prominent protein kinases, present in essentially every tissue but most concentrated in brain. Although it has been about a quarter of a century since the finding, CaM kinase II has been of the major interest in the region of brain science. It plays a multifunctional role in many intracellular events, and the expression of the enzyme is carefully regulated in brain regions and during brain development. Neuronal CaM kinase II regulates important neuronal functions, including neurotransmitter synthesis, neurotransmitter release, modulation of ion channel activity, cellular transport, cell morphology and neurite extension, synaptic plasticity, learning and memory, and gene expression. Studies concerning this kinase have provided insight into the molecular basis of nerve functions, especially learning and memory, and indicate one direction for studies in the field of neuroscience. This review presents the molecular structure, properties and functions of CaM kinase II, as a major component of neurons, based mainly developed on findings made in our laboratory.
著者
林 清五郎 植木 寛 原野 誠子 小宮 順子 井山 駿 原野 一誠 宮田 勝昭 新形 邦宏 米村 嘉郎
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.12, no.11, pp.1271-1276, 1964-11-25 (Released:2008-03-31)
被引用文献数
2 3

Dimethanesulphonylthioalkanes and analogous compounds were synthesized by the reaction of corresponding sodium thiosulphonate and appropriate dibromide to test the carcinostatic activity compaed with Myleran. It was found that some of these compounds inhibited pronouncedly the growth of the solid tumor produced by Ehrlich ascites carcinoma cells.
著者
田之口 真理子 加島 竜彦 雑賀 英之 井上 大志 有本 正生 山口 秀夫
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.37, no.1, pp.68-72, 1989-01-25 (Released:2008-03-31)
参考文献数
31
被引用文献数
11 16

Two new lignans, hernolactone (1) and fernandin (2), isolated from the seeds of Hernandia ovigera L. were synthesized in recemic forms. Firstly, (±)-1 was obtained by utilizing the conjugate addition reaction of 4 with butenolide followed by alkylation with trimethoxybenzyl bromide and subsequent removal of the protecting groups. Synthesis of 2 was pursued using the corresponding 4-phenyl-1, 2-dihydronaphthalene lactone(18). The cleavage of the lactone moiety of 18 afforded an unsaturated hydroxy acid (22). Subsequent hydrogenation of 22 followed by acidification with concetrated hydrochloric acid gave isopicrobernanadin (21), leaving the 2, 3-trans, 3, 4-cis hydroxy acid (23), which was lactonized by means of N, N-dicyclohexylcarbodiimide to afford (±)-2.
著者
田之口 真理子 細野 江津子 北岡 真由子 有本 正生 山口 秀夫
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.39, no.7, pp.1873-1876, 1991-07-25 (Released:2008-03-31)
参考文献数
10
被引用文献数
8 11

Two kinds of lignans were isolated from the seeds of Hernandia ovigera L. in addition to the nine lignans previously reported. One was confirmed as (-)-dimethylmatairesinol (11) and the other was identified as 5'-methoxypodorhizol (14) by comparison with the anthentic sample. An attempt at the cyclization of 14 afforded two compounds which were determined to be isohernandin (15) and an isomer of 15, 2-hydroxymethy 1-5, 6-methylenedioxy-7-methoxy-4-(3', 4', 5'-trimethoxyphenyl)-1, 2, 3, 4-tetrahydronaphthoic acid lactone (16).
著者
山口 秀夫 有本 正生 中島 淳二 田之口 眞理子 深田 能成
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.5, pp.2056-2060, 1986-05-25 (Released:2008-03-31)
参考文献数
16
被引用文献数
10 11

Epipodophyllotoxin (EPT) and podophyllotoxin (PT) were prepared from desoxypodophyllotoxin (DPT), obtained from the seeds of Hernandia ovigera L. (Hernandiaceae) EPT was obtaind together with dehydrodesoxypodophyllotoxin (I) by a radical bromination of DPT with N-bromosuccinimide (NBS) followed by hydrolysis of the resultant 1-bromo-DPT, which was confirmed to be a mixture of 1α- and 1β-bromo compounds (7 : 3). EPT was oxidized with pyridinium chlorochromate to give podophyllotoxone (IV). The stereoselective reduction of IV to afford PT was examined with a variety of reagents, and borane-tert-butylamine complex was found to be effective.
著者
山口 秀夫 中島 淳二 有本 正生 田之口 真理子 石田 寿昌 井上 正敏
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.32, no.5, pp.1754-1760, 1984-05-25 (Released:2008-03-31)
参考文献数
18
被引用文献数
2 5

Two kinds of 4-aryltetralin type lignans, β-peltatin-A methyl ether (I-A) and β-peltatin-B methyl ether (I-B), were synthesized from desoxypodophyllotoxin (DPT), which is available in large quantities from the seeds of Hernandia ovigera L. (Hernandiaceae). The syntheses were achieved via demethylene-DPT (IV), 8-bromo-demethylene-DPT (V) and 8-bromo-DPT (VI). Methylenation of V was carried out successfully by using cesium fluoride and methylene iodide in DMF. Compound I-B was readily obtained by the reaction of VI with cuprous iodide and sodium methoxide in the presence of pyridine. Synthesis of I-A was only achieved by the reaction of lithiated VI with nitrobenzene at-100°C in the presence of tetramethylethylene diamine, and I-A was obtained in low yield, together with I-B.
著者
山口 秀夫 有本 正生 田之口 眞理子 石田 寿昌 井上 正敏
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.30, no.9, pp.3212-3218, 1982-09-25 (Released:2008-03-31)
参考文献数
22
被引用文献数
12 21

Two kinds of lignans were isolated from the seeds of Hernandia ovigera L. (Hernandiaceae) besides the previously reported desoxypodophyllotoxin (DPT), desoxypicropodophyllin, bursehernin and podorhizol, and the structures of the lignans were clarified. One, C23H24O8, named hernandin, was identified as 5-methoxy-desoxypodophyllotoxin (I) by both chemical and X-ray crystallographic methods. The other, C22H18O7, was obtained by purification of a previously isolated impure substance, mp 270-275°C. This compound was identified as 1, 2, 3, 4-dehydrodesoxypodophyllotoxin (II). This is the first report of the natural occurrence of II in plants.
著者
MARIKO TANOGUCHI MASAO ARIMOTO HIDEYUKI SAIKA HIDEO YAMAGUCHI
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.35, no.10, pp.4162-4168, 1987-10-25 (Released:2009-10-19)
参考文献数
21
被引用文献数
17 29

Three kinds of lignans, including a new lignan, named hernolactone, were isolated from the seeds of Hernandia ovigera L. besides six previously reported lignans, desoxypodophyllotoxin (DPT), desoxypicropodophyllin, bursehernin, podorhizol, hernandin and dehydro-DPT. The structure of hernolactone was determined as (2R, 3R) -3- (4′-hydroxy-3′, 5′-dimethoxybenzyl) -2- (3″, 4″, 5″-trimethoxybenzyl) -γ-butyrolactone (IV) and the other two lignans were identified as (-) -yatein ((-) -deoxypodorhizon) (V) and dehydropodophyllotoxin (IX).
著者
井藤 千裕 松井 卓哉 呉 天賞 古川 宏
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.40, no.5, pp.1318-1321, 1992-05-25 (Released:2008-03-31)
参考文献数
12
被引用文献数
10 19

6, 7-Demethylenedesoxypodophyllotoxin (1) was isolated from the seeds of Hernandia ovigera L. (Hernandiaceae) collected in Taiwan, together with several known lignans. This is the first example of the occurrence of 1 in a natural source. The assignments of the 13C-nuclear magnetic resonance signals of several podophyllotoxin analogues isolated from this plant were also established by means of two-dimensional H-C correlation spectroscopy (COSY) and H-C long range COSY techniques.
著者
Teruaki Sakurai
出版者
The Pharmaceutical Society of Japan
雑誌
Journal of Health Science (ISSN:13449702)
巻号頁・発行日
vol.49, no.3, pp.171-178, 2003 (Released:2003-06-01)
参考文献数
28
被引用文献数
15 22

Inorganic arsenic is clearly a toxicant and carcinogen in humans. In mammals, including humans, inorganic arsenic often undergo methylation, forming compounds such as pentavalent dimethyarsinic acid (DMAsV). Recent evidence indicates that DMAsV is a complete carcinogen in rodents while evidence for inorganic arsenic as a carcinogen in rodents remains unclear. Thus, we studied the molecular mechanisms of the in vitro cytolethality of DMAsV compared to that of the trivalent inorganic arsenic, sodium arsenite, using rat liver TRL 1215 cells. Arsenite was very cytotoxic in these cells; its lethal concentration in vitro in 50% of a population (LC50) was 20 μM after a 48-hr exposure. With arsenite, most dead cells showed histological and biochemical evidence of necrosis. The arsenite cytolethality markedly increased when cellular reduced glutathione (GSH) was depleted with the glutathione synthase inhibitor, L-buthionine-[S,R]-sulfoximine (BSO). In contrast, DMAsV was nearly three orders of magnitude less cytotoxic (LC50 = 1.5 mM) although evidence showed the predominating form of death was apoptosis. Surprisingly, GSH depletion actually decreased the DMAsV-induced apoptosis. It is suggested that DMAsV requires intracellular GSH to induce apoptosis. Ethacrynic acid (EA), an inhibitor of glutathione S-transferase that catalyzes GSH-substrate conjugation, and aminooxyacetic acid (AOAA), an inhibitor of β-lyase which catalyzes the final breakdown of GSH-substrate conjugates, were also effective in suppressing the DMAsV-induced apoptosis. These findings indicate that DMAsV was likely conjugated in some form with cellular GSH, and this conjugate induced apoptosis during subsequent metabolic reactions. Because apoptosis is a process by which organisms eliminate abnormal cells, the arsenic biomethylation in the human body may essentially a detoxicating event.
著者
Yoshiaki Kato Kenji Niiyama Hideki Jona Shigemitsu Okada Atsushi Akao Shouichi Hiraga Yoshimi Tsuchiya Koji Tomimoto Toshiaki Mase
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.50, no.8, pp.1066-1072, 2002 (Released:2002-08-01)
参考文献数
16
被引用文献数
6 8

An asymmetric synthesis of a selective endothelin A receptor antagonist 1b is described. Asymmetric conjugate addition of aryllithium derived from 18 to the chiral oxazoline 17 followed by hydrolysis afforded 15 in 96% ee via purification as (S)-(−)-1-phenylethylamine salt. Pd(OAc)2/dppf (1,1′-bis(diphenylphosphino)ferrocene) catalyzed carbonylation followed by chemoselective addition of aryllithium derived from 23 which gave ketone 24. Diastereoselective reduction of the ketone with catecholborane followed by concomitant activation of the resulting alcohol and cyclization gave the late intermediate 26. Introduction of amino moiety on the pyridine ring by imidoyl rearrangement followed by deprotection and purification by crystallization furnished the enantiomerically pure target molecule 1b in 8% overall yield from 16.
著者
広田 耕作 丸橋 和夫 浅尾 哲次 千田 重男
出版者
The Pharmaceutical Society of Japan
雑誌
Chemical and Pharmaceutical Bulletin (ISSN:00092363)
巻号頁・発行日
vol.30, no.9, pp.3377-3379, 1982-09-25 (Released:2008-03-31)
参考文献数
15
被引用文献数
4 8

Thermolysis of 6-azido-1, 3-dimethyluracil (1) in formamide gave 1, 3, 6, 8-tetramethylpyrimido [5, 4-g] pteridine-2, 4, 5, 7 (1H, 3H, 6H, 8H)-tetrone (3), while the same reaction in N, N-dimethylformamide (DMF) gave 3-(5-amino-1, 3-dimethyluracil-6-yl)-4, 6-dimethyl-[1, 2, 3] triazolo [4, 5-d] pyrimidine-5, 7 (4H, 6H)-dione (4), which was converted into 3 in refluxing formamide. Compound 4 was also obtained by the treatment of 1 with 4, 6-dimethyl [1, 2, 3] triazolo [4, 5-d] pyrimidine-5, 7 (4H, 6H)-dione (5) in refluxing DMF. The mechanism of these reactions is discussed.
著者
伊藤 豊 矢野 真吾 渡辺 和夫 山中 悦二 相見 則郎 坂井 進一郎
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.6, pp.1702-1706, 1990-06-25 (Released:2008-03-31)
参考文献数
16
被引用文献数
10 18

We investigated the selectivities and structure requirements for alpha-1 and alpha-2 adrenoceptor blocking activities of yohimbine (YO) and its 12 related analogs, such as β-yohimbine (β-YO), dihydrocorynantheine (DHC) and (-)indoloquinolizidine ((-)IQ). The affinity of YO analogs to alpha-adrenoceptor was assessed by measuring their blockade of pressor responses to epinephrine in pithed rats. Among YO structure groups, the potency order was YO>DHC=β-YO>geissoschizine methylether>14β-hydroxy YO>14β-benzoyloxy YO (inactive). (-)IQ was slightly less potent than YO, but much stronger than (+)IQ. Among (±)IQ structure groups, the potency order was (±)IQ>(±)1, 12b-trans-1-hydroxy IQ»(±)1, 12b-cis-1-hydroxy IQ (imactive). (±)Borrerine was active, but (±)desmethylborrerine was inactive. The alpha-1 blocking activities of the four compounds YO, β-YO, DHC and (-)IQ, were assessed in experiments of pressor responses to methoxamine in pithed rats and contractile responses to methoxamine in the rat vas deferens. The potency order was (-)IQ>YO>DHC>β-YO. Furthermore, the alpha-2 blocking activities of the four analogs were assessed in experiments of pressor responses to clonidine and inhibition of electrically driven cardioacceleration by clonidine, in pithed rats. The potency order was YO>β-YO>(-)IQ>DHC. Based on the potency ratio between alpha-1 and alpha-2 blocking activities, DHC or YO was most selective for alpha-1 or alpha-2 subtype, respectively, among the four YO analogs. These results suggest that the A, B, C and D rings of YO analogs and their planarity are necessary for the affinity to alpha-adrenoceptors and that the predominant conformation of the carboxymethyl or hydroxy group on the E ring of YO structure determines the selectivity for alpha-1 and alpha-2 blocking activities.
著者
山中 悦二 成嶋 真弓 犬飼 邦江(旧姓長島) 坂井 進一郎
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.1, pp.77-81, 1986-01-25 (Released:2008-03-31)
参考文献数
12
被引用文献数
7 13

Convenient syntheses of 1, 2, 3, 4, 6, 7, 12, 12b-octahydroindolo[2, 3-α]quinolizine derivatives (4a, b) and a relatd unsaturated lactam (14) are described. The condensation of tryptamine (1) with 8a, b (prepared from 7a, b by decarboethoxylation), followed by treatment with alkali gave the lactams (4a, b), respectively. The stereochemistry of 4b was determined by conversion to the known cis- and trans-compounds (5b). The condensation of 1 with the sulfenylated ester (10), which was prepared in two ways, followed by treatment with alkali gave the lactams (12a, b). Oxidation of 12a, b with m-chloroperbenzoic acid gave the sulfoxides (13) which were heated at 50°C to give the lactams (14, 15) and the pyridone (16).
著者
山中 悦二 丸田 悦子 笠松 里江 相見 則郎 坂井 進一郎 / / TANOMJIT SUPAVITA J. DAVID PHILLIPSON
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.9, pp.3713-3721, 1986-09-25 (Released:2008-03-31)
参考文献数
21
被引用文献数
4 6

Oxidation of the enamine (6) with dibenzoyl peroxide followed by reduction with NaBH4 gave the benzoate (8), which was converted to the cis-hydroxyl compound (9), while hydroboration-oxidation of 6 gave the trans-isomer (11). Treatment of a mixture of the enamines (13 and 14) with dibenzoyl peroxide/NaBH4 gave the benzoates (15 and 16), which were converted to 14α-hydroxy-3-isorauniticine (17) and the acetal (18), respectively. Hydroboration-oxidation of 13 gave 14α-hydroxyrauniticine (2), which was found to be identical with the natural alkaloid whose structure had erroneously been proposed as 14β-hydroxy-3-isorauniticine (4).