Secoiridoid glucosides and unusual recyclized secoiridoid aglycones from Ligustrum vulgare.

Phytochemical investigation of the dried leaves and twigs of Ligustrum vulgare has led to the isolation of the secoiridoid glucosides, (2''R)- and (2''S)-10-hydroxy-2''-methoxyoleuropeins (1 and 2), and the secoiridoid aglycones, ligustrohemiacetals A (3) and B (4). Their structures were elucidated by spectroscopic and chemical means. Enzymatic hydrolysis of 10-hydroxyoleuropein to the analog of ligustrohemiacetals A and B led to the structural revision of jasmolactones.

Phenolic and iridoid glycosides from Strychnos axillaris.

Five phenolic glycosides 1-5 and an iridoid glucoside 6 were isolated, together with 22 known compounds, from the dried barks and woods of Strychnosaxillaris. Their structures were determined by application of spectroscopic (NMR, MS) and chemical methodologies.

Indole alkaloids and other constituents of Rauwolfia serpentina.

From the dried roots of Rauwolfia serpentina were isolated five new indole alkaloids, N(b)-methylajmaline (1), N(b)-methylisoajmaline (2), 3-hydroxysarpagine (3), yohimbinic acid (4), isorauhimbinic acid (5), a new iridoid glucoside, 7-epiloganin (6), and a new sucrose derivative, 6'-O-(3,4,5-trimethoxybenzoyl)glomeratose A (7), together with 20 known compounds. The structures of the new compounds were determined by spectroscopic and chemical means. The inhibitory activities of the selected alkaloids on topoisomerase I and II and their cytotoxicity against the human promyelocytic leukemia (HL-60) cell lines were assessed.

Three isocoumarins and a benzofuran from the cultured lichen mycobionts of Pyrenula sp.

The spore-derived mycobionts of the lichen Pyrenula sp. were cultivated on a malt-yeast extract medium supplemented with 10% sucrose. The investigation of their metabolites resulted in isolation of four compounds, three isocoumarins and a biogenetically related benzofuran; their structures were determined by spectroscopic methods.

Quantitative structure-activity relationship analyses of antioxidant and free radical scavenging activities for hydroxybenzalacetones.

Antioxidant activities for a series of hydroxybenzalacetones, OH-BZ, were evaluated by measuring inhibitory potencies of OH-BZ against lipid peroxidation induced by t-BuOOH or gamma-irradiation. Their quantitative structure-activity relationship (QSAR) studies indicated that the activities are mainly governed by electronic and steric factors. To rationalize these results, we also performed QSAR analyses for DPPH radical scavenging activities of OH-BZ, which indicated that antioxidant and radical scavenging activities could be expressed by the same physicochemical parameters but the hydrogen bonding behavior of phenolic OH varies with the reaction medium.

Flavonoid glycosides from Adina racemosa and their inhibitory activities on eukaryotic protein synthesis.

From the dried leaves, flowers, and twigs of Adina racemosa, five new flavonoid glycosides, quercetin 3-O-alpha-l-rhamnopyranosyl(1-->6)-(3-O-trans-p-coumaroyl)-beta-d-galactopyranoside (1), quercetin 3-O-alpha-l-rhamnopyranosyl(1-->6)-[(4-O-trans-p-coumaroyl)-alpha-l-rhamnopyranosyl(1-->2)]-(4-O-trans-p-coumaroyl)-beta-d-galactopyranoside (2), kaempferol 3-O-alpha-l-rhamnopyranosyl(1-->6)-[(4-O-trans-p-coumaroyl)-alpha-l-rhamnopyranosyl(1--> 2)]-(4-O-trans-p-coumaroyl)-beta-d-galactopyranoside (3), quercetin 3-O-alpha-l-rhamnopyranosyl(1-->6)-[(4-O-trans-p-coumaroyl)-alpha-l-rhamnopyranosyl(1-->2)]-(3-O-trans-p-coumaroyl)-beta-d-galactopyranoside (4), and quercetin 3-O-alpha-l-rhamnopyranosyl(1-->6)-[(4-O-trans-caffeoyl)-alpha-l-rhamnopyranosyl(1-->2)]-(3-O-trans-p-coumaroyl)-beta-d-galactopyranoside (5), and eight known compounds were isolated. The structures of the new compounds were determined by spectroscopic and chemical means. Their inhibitory activities on protein synthesis were assessed. The new glycosides were found to be inhibitors of eukayrotic, but not prokaryotic, protein synthesis.

Two triterpenoid saponins from Neonauclea sessilifolia.

From the dried roots of Neonauclea sessilifolia (Rubiaceae), two new triterpenoid saponins, 3-O-beta-D-glucopyranosyl-(1-->2)-beta-D-quinovopyranosyl quinovic acid (1) and 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-quinovopyranosyl pyrocincholic acid 28-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl ester (2), were isolated, together with five known saponins. The structures of the new saponins were determined by spectroscopic and chemical means.

Six secoiridoid glucosides from Adina racemosa.

Six novel secoiridoid glucosides, adinosides A (1), B (2), C (3), D (4), E (5), and grandifloroside 11-methyl ester (6) were isolated, together with 27 known compounds, from the dried leaves, flowers, and twigs of Adina racemosa. The structures of the new compounds were determined by spectroscopic (NMR, MS) and chemical means.

Phenyl ethers from cultured lichen mycobionts of Graphis scripta var. serpentina and G. rikuzensis.

Spore-derived mycobionts of the lichen Graphis scripta var. serpentina and G. rikuzensis were cultivated on a malt-yeast extract medium supplemented with 10% sucrose and their metabolites were investigated. 3,3'-Dihydroxy-5,5'-dimethyldiphenyl ether was isolated from the cultures of the mycobionts of G. scripta var. serpentina, while a new phenyl ether, rikuzenol, along with two known diphenyl ethers, violaceol-I and violaceol-II, were isolated from those of G. rikuzensis. The structure of the new compound was determined by spectroscopic methods. Violaceol-I was chemically synthesized and interconversion between violaceol-I and violaceol-II was proven.

Two chromone-secoiridoid glycosides and three indole alkaloid glycosides from Neonauclea sessilifolia.

From the dried roots of Neonauclea sessilifolia, two new chromone-secoiridoid glycosides, sessilifoside and 7"-O-beta-D-glucopyranosylsessilifoside, and three novel indole alkaloid glycosides, neonaucleosides A, B, and C, were isolated along with the main known glycosides, 5-hydroxy-2-methylchromone-7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside, sweroside, loganin, grandifloroside, and quinovic acid 3 beta-O-beta-D-quinovopyranoside-28-O-beta-D-glucopyranoside. The structures of these new glycosides were determined by spectroscopic and chemical means. Neonaucleoside A and its C-3 epimer were prepared from secologanin and tryptamine.

6H-dibenzo[b,d]pyran-6-one derivatives from the cultured lichen mycobionts of Graphis spp. and their biosynthetic origin.

The spore-derived mycobionts of the lichen Graphis prunicola, G. cognata and G. scripta were cultivated on a malt-yeast extract medium supplemented with 10% sucrose and their metabolites were investigated. Graphislactones A-D were isolated from the cultures of G. prunicola, while alternariol and graphislactones A and C were isolated from those of G. cognata. From the cultured mycobionts of G. scripta, a new 6H-dibenzo[b,d]pyran-6-one derivative, graphislactone E with graphislactones A and C was obtained. On the other hand, cultivation of the mycobionts of G. prunicola on a malt-yeast extract medium supplemented with 2.5% sucrose and 0.25% sodium acetate produced two new metabolites, graphislactones E and F. Their structures were determined by spectroscopic methods. The biogenetic origin of the carbon skeleton in both compounds was verified by administering sodium [1-13C]-acetate and sodium [1,2-13C(2)]-acetate.

Nine new secoiridoid glucosides from Jasminum nudiflorum.

Phytochemical study of the leaves of Jasminum nudiflorum has led to the isolation of nine new secoiridoid glucosides, jasnudiflosides F-L (1-7), nudifloside D (8) and isooleoacteoside (9). The structures of these compounds were elucidated on the basis of chemical and spectroscopic evidence.

Secoiridoid and iridoid glucosides from Syringa afghanica.

Phytochemical investigation of the dried leaves of Syringa afghanica, has led to the isolation of nine secoiridoid glucosides, safghanosides A-H and 2"-epi-frameroside, as well as an iridoid glucoside, syringafghanoside along with nineteen known compounds. The structures were elucidated by spectroscopic and chemical means.

Flavonoid glycosides from Rhazya orientalis.

Six new flavonoid glycosides, quercetin 3-O-alpha-L-rhamnopyranosyl(1-->6)-[alpha-L-rhamnopyranosyl(1-->2)]-(4-O-trans-p-coumaroyl)-beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside (1), quercetin 3-O-alpha-L-rhamnopyranosyl(1-->6)-[alpha-L-rhamnopyranosyl(1-->2)]-(3-O-trans-p-coumaroyl)-beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside (2), isorhamnetin 3-O-alpha-L-rhamnopyranosyl(1-->6)-[alpha-L-rhamnopyranosyl(1-->2)]-(4-O-trans-p-coumaroyl)-beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside (3), isorhamnetin 3-O-alpha-L-rhamnopyranosyl(1-->6)-[alpha-L-rhamnopyranosyl(1-->2)]-(3-O-trans-p-coumaroyl)-beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside (4), isorhamnetin 3-O-alpha-L-rhamnopyranosyl(1-->6)-[alpha-L-rhamnopyranosyl(1-->2)]-(4-O-cis-p-coumaroyl)-beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside (5), and isorhamnetin 3-O-alpha-L-rhamnopyranosyl(1-->6)-[alpha-L-rhamnopyranosyl(1-->2)]-(4-O-trans-feruloyl)-beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside (6), were isolated from the dried aerial parts of Rhazya orientalis. The structures of 1-6 were determined by spectroscopic and chemical means.

Tetrahydroisoquinoline-monoterpene glycosides from Cephaelis acuminata.

From the dried roots of Cephaelis acuminata, five tetrahydroisoquinoline-monoterpene glycosides, 2-O-beta-D-glucopyranosyldemethylalangiside, demethylisoalangiside, 6"-O-beta-D-glucopyranosylipecoside, 6"-O-alpha-D-glucopyranosylipecoside and (4R)-4-hydroxyipecoside, were isolated. The structures of these glycosides were determined by spectroscopic and chemical means.