Tsunashi Kamo

Anti-inflammatory sesquiterpenes from Curcuma zedoaria

From the methanolic extract of the rhizome of Curcuma zedoaria, we isolated anti-inflammatory sesquiterpene furanodiene (1) and furanodienone (2) along with new sesquiterpene compound 3 and known eight sesquiterpenes, zederone (4), curzerenone (5), curzeone (6), germacrone (7), 13-hydroxygermacrone (8), dehydrocurdione (9), curcumenone (10), and zedoaronediol (11). Their structures were elucidated on the basis of spectroscopic data. The anti-inflammatory effect of isolated components on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation of mouse ears were examined. Compounds 1 and 2 suppressed the TPA-induced inflammation of mouse ears by 75% and 53%, respectively, at a dose of 1.0 µmol. Their activities are comparable to that of indomethacin, the normally used anti-inflammatory agent.

First Isolation of Natural Cyanamide as a Possible Allelochemical from Hairy Vetch Vicia villosa

Cyanamide was isolated from the leaves and stems of hairy vetch (Vicia villosa), guided by plant growth inhibitory activity against lettuce (Lectuca sativa) seedlings. A large proportion of the inhibitory activity in the crude extract was explained by the presence of cyanamide, suggesting it to be a possible allelochemical in this species. The amount in a 9-day-old seedling, which had been grown without nutrients, reached approx. 40 times that of a nongerminated seed, demonstrating cyanamide biosynthesis in the seedlings. This is the first report on the isolation of a possible allelochemical from hairy vetch and also of the finding of cyanamide as a natural product.

Anti-inflammatory Cyathane Diterpenoids from Sarcodon scabrosus

Four novel diterpenoids were isolated from the fruiting bodies of Sarcodon scabrosus (Fr.) Karst. (Boraginaceae) together with neosarcodonin A. One of the novel compounds was elucidated to be a cyathane diterpenoid, namely neosarcodonin O, by its spectral data. The others were characterized as 19-O-linoleoyl, 19-O-oleoyl and 19-O-stearoyl derivatives of sarcodonin A, after comparison with the authentic samples synthetically prepared from sarcodonin A. These compounds, together with the five 19-O-acyl derivatives synthesized from sarcodonin A, each exhibited inhibitory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation on mouse ears by topical application.

AN EFFICIENT SYNTHESIS OF PROCYANIDINS USING EQUIMOLAR CONDENSATION OF CATECHIN AND/OR EPICATECHIN CATALYZED BY YTTERBIUM TRIFLATE

Stereoselective synthesis of catechin and epicatechin dimers under intermolecular condensation of equimolar amount of catechin derivatives catalyzed by Yb(OTf) 3 . The coupled products were successfully converted to procyanidins B1, B2, B3, and B4, respectively. Procyanidins Bl, B2, B3, and B4 could be used as standard compounds for identifying the polyphenols in natural source.

Myrsinoic Acid E, an Anti-inflammatory Compound from Myrsine seguinii

The methanolic extract of Myrsine seguinii yielded the novel anti-inflammatory compound, myrsinoic acid E (1), whose structure was elucidated to be 3,5-digeranyl-4-hydroxy benzoic acid. We synthesized 1- and its 3,5-diprenyl (2) and 3,5-difarnesyl analogues (3). Compounds 1-3 suppressed 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation of mouse ears by 59%, 14%, and 69% at a dose of 1.4 μmol.

Quantification of Cyanamide Contents in Herbaceous Plants

Cyanamide (NH2CN) is found in nature, although it has long been recognized as an industrial product. Distribution of cyanamide in the plant kingdom was investigated using a direct quantitative determination method to detect and measure cyanamide by stable isotope dilution gas chromatography–mass spectrometry (the SID–GC–MS method). The SID–GC–MS method proved to be a robust way to quantify cyanamide contents in the extracts of 101 species of herbaceous plants. The average recovery of cyanamide from all plants tested was 55.6±20.3%. Vicia villosa and V. cracca contained cyanamide at 369–498 μg/gFW and 3,460–3,579 μg/gFW respectively, while the other 99 species contained no detectable cyanamide (<1 μg/gFW). This result suggests that distribution of cyanamide in the plant kingdom is limited and uneven.

A tyrosinase inhibitor, Daedalin A, from mycelial culture of Daedalea dickinsii.

A chromene-type compound, daedalin A (1), was isolated from mycelial culture broth of Daedalea dickinsii. Based on spectroscopic data, the structure of 1 was found to be (2R)-6-hydroxy-2-hydroxymethyl-2-methyl-2H-chromene. Daedalin A (1) strongly inhibited the activity of tyrosinase (IC50: 194 μM). In addition, 1 also showed 1,1-diphenyl-2-picrylhydrazyl scavenging activity (IC50: 16.9 μM) and superoxide anion scavenging activity (IC50: 28.5 μM).

1,2-Dehydrolactarolide A, a new plant growth regulatory lactarane sesquiterpene from Lactarius vellereus.

A new lactarane sesquiterpene, 1,2-dehydrolactarolide A (1), together with lactarorufin A (2), 3-O-ethyllactarolide A (3) and 3-O-ethyllactarolide B (4), was isolated from a mushroom of the Russulaceae family, Lactarius vellereus. Additionally, two lactarane sesquiterpenes, lactarorufin A (2) and lactarolide A (5) were isolated from L. subpiperatus. 1,2-Dehydrolactarolide A (1) showed promotional activity (152% at 3.6×101 μM) toward radicle elongation in lettuce seedlings.

New Plant Growth Promoters, Repraesentins A, B and C, from Lactarius repraesentaneus

Three new plant growth regulatory sesquiterpenoids were isolated from the Lactarius repraesentaneus fungus. Their structures were elucidated to be a protoilludene sesquiterpene, namely repraesentin A (1), and two related sesquiterpenes, namely repraesentins B (2) and C (3). Compounds 1-3 showed promotion activities toward the radicle elongation of lettuce seedlings by 136%, 118% and 184% at 67 ppm, respectively.

Evidence of cyanamide production in hairy vetch Vicia villosa

Cyanamide (NH2CN) has recently been isolated as a plant growth inhibitor from Vicia villosa, which is the first discovery of cyanamide from natural sources. To reveal the presence of the biosynthesized cyanamide in plants, 3.4 mM potassium (15N)nitrate was administered to 15- to 35-day-old plants of V. villosa, from which the cyanamide was purified and subjected to GC/MS analysis. The isotopic ratio 15N/(14N + 15N) of the cyanamide was calculated to be 0.143, while that of the cyanamide extracted from V. villosa grown in the presence of a natural N source was 0.0065. The 15N-enrichment proved de novo biosynthesis of cyanamide.