Nobuji Nakatani

Anti-oxidative and anti-inflammatory curcumin-related phenolics from rhizomes of Curcuma domestica

Abstract Two new natural phenolics were isolated from the rhizomes of Curcuma domestica along with four known curcuminoids. The structures of the former wer

Antioxidative curcuminoids from rhizomes of Curcuma xanthorrhiza

A new curcumin analogue has been isolated from the rhizomes of Curcuma xanthorrhiza along with four known curcuminoids, and its structure has been determined as 1-(4-hydroxy-3,5-dimethoxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)-(1E,6E)-1,6-heptadiene-3,4-dione by spectral data. The new compound showed potent antioxidant activity against autoxidation of linoleic acid in a water-alcohol system.

Antimicrobial phenylpropanoids from Piper sarmentosum

Abstract One new and three known phenylpropanoids have been isolated from the leaves of Piper sarmentosum . They are 1-allyl-2,6-dimethoxy-3,4-methylenedioxybenzene, 1-allyl-2,4,5-trimethoxybenzene, 1-(1- E -propenyl)-2,4,5-trimethoxybenzene and 1-allyl-2-methoxy-4,5-methylenedioxybenzene. The new compound showed antimicrobial activity against Escherichia coli and Bacillus subtilis .

Cyclic diarylheptanoids from rhizomes of Zingiber officinale

Abstract Five new diarylheptanoids were isolated from the rhizomes of Zingiber officinale and their structures elucidated by spectroscopic and chemical methods. They were oxygenated at C-1, 3 and 5 on the heptane chain and cyclized between C-1 and C-5 through oxygen.

Pungent Alkamides from Spilanthes acmella L. var. oleracea Clarke

A main pungent amide, spilanthol (1), and three alkamides, (2E)-N-(2-methylbutyl)-2-undecene-8,10-diynamide (2), (2E,7Z)-N-isobutyl-2,7-tridecadiene-10,12-diynamide (3), and (7Z)-N-isobutyl-7-tridecene-10,12-diynamide (4) were isolated from the flower heads of Spilanthes acmella L. var. oleracea Clarke. Their structures were established by spectroscopic methods. Compounds 2 and 4 were new and 3 was found for the first time in Spilanthes species. Chemotaxonomic aspects are discussed.

Antioxidative phenylpropanoids from berries of Pimenta dioica

A phenylpropanoid, threo-3-chloro-1-(4-hydroxy-3-methoxyphenyl)propane-1,2-diol, was isolated from the berries of Pimenta dioica together with five known compounds, eugenol, 4-hydroxy-3-methoxycinnamaldehyde, 3,4-dimethoxycinnamaldehyde, vanillin and 3-(4-hydroxy-3-methoxyphenyl)propane-1,2-diol. In addition, the stereochemistry of 3-(4-hydroxy-3-methoxyphenyl)propane-1,2-diol was determined. The phenylpropanoids inhibited autoxidation of linoleic acid in a water-alcohol system.

Orthosiphol A and B, novel diterpenoid inhibitors of TPA (12-O-tetradecanoylphorbol-13-acetate)-induced inflammation, from Orthosiphon stamineus

Abstract Two novel highly oxygenated pimarane diterpenes, orthosiphol A (1) and B (2), have been isolated from the dry leaves of Orthosiphon stamineus Benth (Labiatae). Their structures were elucidated by spectroscopic and chemical methods. Orthosiphol A and B showed potent inhibitory activity against the inflammation induced by a tumor promoter, TPA (12-O-tetradecanoylphorbol-13-acetate), on mouse ears

Gingerdiol related compounds from the rhizomes of Zingiber officinale

Abstract [6]-Gingerdiol and four analogues, (3R,5S)-5-acetoxy-3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)decane, (3R,5S)-3-acetoxy-5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)decane, (3R,5S)-3,5-diacetoxy-1-(4-hydroxy-3-methoxy-phenyl)decane and (3R,5S)-3,5-diacetoxy-1-(3,4-dimethoxyphenyl)decane, were isolated from the rhizomes of Zingiber officinale. Their structures were established by chemical and spectroscopic evidence.

Novel and efficient method for esterification, amidation between carboxylic acids and equimolar amounts of alcohols, and amines utilizing Me2NSO2Cl and N,N-dimethylamines; its application to the synthesis of coumaperine, a natural chemopreventive dieneamide

Abstract Various carboxylic esters or amides were prepared in good to excellent yield between carboxylic acids and equimolar amounts of alcohols or amines under very mild conditions (0–45°C; within 3 h) using dimethylsulfamoyl chloride (Me 2 NSO 2 Cl; 1 ) combined with N , N -dimethylamines (Me 2 NR: 2a ; R=Me, 2b ; R=Bu). The choice of the sulfamoyl chloride and the amine is crucial for the reaction; that is, sterically uncrowded amines accelerated the present esterification and amidation. This agent had some advantages over methanesulfonyl chloride ( 3 )/amines as for the atom-economy, avoidance of side reactions, and had very high chemoselectivity toward the carboxyl group vs the hydroxyl group; the experiment was performed by the addition of 1 to the mixture of carboxylic acids and alcohols. Application of this method to the synthesis of coumaperine, a chemopreventive natural product, was performed using the present amidation as a key step.

Diaryldimethylbutane lignans from Myristica argentea and their antimicrobial action against Streptococcus mutans

Abstract Four 1,4-diaryl-2,3-dimethylbutane type lignans were isolated from the aril of Myristica argentea . In addition to two known lignans, namely erythro -austrobailignan-6 and meso -dihydroguaiaretic acid, two new compounds were determined to be rel -1-(4-hydroxy-3-methoxyphenyl)-4-(3,4-methylenedioxyphenyl)-2,3-dimethylbutan-1-o1 (myristargenol A) and rel -1,4-di(4-hydroxy-3-methoxyphenyl)-2,3-dimethylbutan-1-o1 (myristargenol B) by chemical and spectroscopic methods.