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A phytochemical investigation on the flesh fruits of atemoya led to the isolation of seven new kaurane type diterpenoids, (4S*,5S*,8S*,9R*,10S*,13R*,16R*)-16-hydro-18-nor-kauran-4,17-diol (1), (4S*,5S*,8S*,9R*,10S*,13R*,16S*)-18-nor-kauran-4,16,17-triol (2), (4S*,5S*,8S*,9R*,10S*,13R*,16S*)-17-acetoxy-18-nor-kauran-4,16-diol (3), (4S*,5S*,8S*,9R*,10S*,13R*,16R*)-18-nor-kauran-4,16,17-triol (4), (4S*,5S*,8S*,9R*,10S*,13R*,16S*)-17-acetoxy-16-hydro-18-nor-kauran-4-ol (5), (4R*,5S*,8S*,9R*,10S*,13R*,16S*)-16,17-dihydroxy-19-nor-kauran-4-hydroperoxide (6), and (4R*,5S*,8S*,9R*,10S*,13R*,16S*)-kauran-16,19-diol (7) along with 26 known ent-kaurane compounds. Their structures are determined on the basis of spectroscopic data and optical rotation. Compounds 1-5 were new 18-nor-kauran-4-ol type diterpenoids, which are very rarely obtained from natural sources.

Alkaline hydrolysis of crude resin glycoside fraction of the seeds of Ipomoea muricata (L.) Jacq. (Convolvulaceae) yielded a new glycosidic acid, muricatic acid D; three known glycosidic acids, namely, muricatic acids A, B, and C; and three known organic acids, namely, isobutyric, 2S-methylbutyric, and 2S-methyl-3S-hydroxybutyric acid. Two new genuine resin glycosides with macrolactone structures (jalapins), muricatins X and XI, were also isolated from the fraction. Their structures were determined using spectroscopic data and chemical evidence.

Four hexaglycosides of methyl 3S,12S-dihydroxyhexadecanoate (1-4) were provided after treatment of the crude convolvulin fraction from Rhizoma Jalapae Braziliensis (the root of Ipomoea operculata (GOMES) MART., Convolvulaceae) with indium(III) chloride in methanol. The structures of 1-4 were elucidated on the basis of spectroscopic and chemical methods. Their sugar moieties were partially acylated with organic acids including (3S,9R)-3,6:6,9-diepoxydecanoic (exogonic) acid, (E)-2-methylbut-2-enoic (tiglic) acid, and isovaleric acid.

Four new acylated glycosidic acid methyl esters were isolated after treatment of the crude ether-insoluble resin glycoside (convolvulin) fraction obtained from the seeds of Quamoclit pennata BOJER (Convolvulaceae) with indium(III) chloride in methanol. Their structures were elucidated on the basis of spectroscopic data and chemical conversions.

Treatment of the ether-insoluble resin glycoside (convolvulin) fraction from seeds of Quamoclit pennata (Convolvulaceae) with indium(III) chloride in methanol provided three oligoglycosides of hydroxy fatty acid (glycosidic acid) methyl esters and two methyl glycosides, which were partially acylated by a glycosidic acid, 7S-hydroxydecanoic acid 7-O-β-D-quinovopyranoside (quamoclinic acid B) and/or two organic acids, (E)-2-methylbut-2-enoic (tiglic) acid and/or 3R-hydroxy-2R-methylbutyric (nilic) acid. Their structures were elucidated on the basis of spectroscopic data and chemical conversions.

Three new resin glycosides, quamoclins V (1), VI (2), and VII (3) and a new tetrahydropyran derivative, quamopyran (4), were isolated from the seeds of Quamoclit pennata BOJER (Convolvulaceae). The chemical structures of these compounds were determined primarily on the basis of spectroscopic data. The carboxyl group of the aglycone, 11S-convolvulinolic acid, of 1 and 2 was linked intermoleculary with a hydroxy group of the sugar moiety to form a macrocyclic ester structure, as in already known jalapins, and 3 was an acylated glycosidic acid methyl ester. All of the sugar moieties of 1-3 were acylated by one 2S-methylbutyric acid. Compound 4 was a diketone having a tetrahydropyran ring.

Alkaline hydrolysis of the crude resin glycoside fraction of the leaves, stems, and roots of Calystegia soldanella ROEM. et SCHULT. (Convolvulaceae) gave four new glycosidic acids, named calysolic acids A, B, C, and D, along with one known glycosidic acid, soldanellic acid B, and three organic acids, 2S-methylbutyric, tiglic, and 2S,3S-nilic acids. The structures of the new glycosidic acids were characterized on the basis of spectroscopic data and chemical evidence.

Four new iridoid glucosides were isolated from the whole plant of Ajuga reptans L. (Labiatae) along with four known iridoid glucosides, one known diterpenoid glycoside, one known aliphatic alcohol glycoside, and three known ecdysteroids. Their chemical structures were determined on the basis of spectroscopic data and chemical evidence. The diterpenoid glycoside exhibited 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and H₂O₂ scavenging activities.

Garlicnin A (1), a new stable, sulfur-containing compound isolated from a fraction of the acetone extracts of Allium sativum L. garlic bulbs, showed the potential to suppress tumor cell proliferation by inhibiting the polarization of M2 alternatively activated macrophages, and its structure was characterized as 3,4-dimethyl-5-(4,5-dithia-1E,7-octadiene)-tetrahydrothiophene-2-sulfoxide-S-oxide, on the basis of the results of spectroscopic analysis results.

A new dolabellane diterpene glycoside, named squoside A, and three new cycloartane glycosides, named squarrosides V, VI, and VII, have been isolated from the dried aerial parts of Thalictrum squarrosum (Ranunculaceae). Their structures were determined by two dimensional (2D) NMR spectroscopic analysis and chemical evidence.

Four new ent-kaurane diterpenoids (16R)-ent-kauran-17,19-diol (1), (16R)-17-hydroxy-ent-kauran-19-oic acid (2), (16S)-17-hydroxy-ent-kauran-19-oic acid (3), and (16R)-17-dimethoxy-ent-kauran-19-oic acid (4) have been isolated from the fresh fruits of Annona cherimola together with eight known compounds. Their structures are determined on the basis of spectroscopic data and optical rotation.

Novel Cucurbitane-type glycosides, 5beta,19beta-epoxy-29-nor-3,11-dioxo-cucurbit-24-ene-27-oic acid 27-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (1) and 19,29-nor-3,11-dioxo-cucurbit-4,24-diene-27-oic acid 27-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (2) were isolated from the roots of Siraitia grosvenori SWINGLE.

A new characteristic steroidal glycoside of the 23S,26R-hydroxylated spirostanol-type named indioside F was isolated from the fruit of Solanum indicum, along with indioside A and protodioscin. On the basis of spectroscopic analysis, the structure of indioside F was found to be 3-O-alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucopyranosyl (beta-chacotriosyl) (22R,23S,25R,26R)-spirost-5-ene-3beta,23,26-triol.

Four acyclic diterpene glycosides were extracted from Habanero, the fruits of Capsicum chinense JACQ., which is known as one of the hottest peppers in existence. Two of these glycosides were identified as capsianoside XIII and capsianoside XV. The other two were new ones and were characterized as 3-O-beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl 17,19-dihydroxy-6E,10E,14Z-(3S)-geranyllinalool 17-O-beta-D-glucopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-[alpha-L-rhamnopyranosyl-(1-->6)]-beta-D-glucopyranoside and 3-O-beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl 6E,10E,14Z-(3S)-17-hydroxy-geranyllinalool 17-O-[3-O-beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl 6'E,10'E,14'Z-(3'S)-13'R,19'-dihydroxy-geranyllinalool-16'-oyl (16'-->2)-[alpha-L-rhamnopyranosyl-(1-->3)]-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl-(1-->6)]-beta-D-glucopyranoside.

Three new steroidal glycosides, named solaviasides A, B, and C, have been isolated from the fruits of Solanum viarum DUNAL (syn. S. khasianum var. chatterjeeanum, Solanaceae), along with seven known ones. Their chemical structures were determined on the basis of spectroscopic data and chemical evidence.

Conversion of the spirosolane-type glycoside, esculeoside A, a major component contained in the ripe tomato Lycopersicon esculentum fruits, into a solanocapsine-type sapogenol, esculeogenin B-2, (5alpha,22S,23R,25S)-22,26-epimino-16beta,23-epoxy-3beta,23,27-trihydroxycholestane, and esculeogenin B-1, (5alpha,22R,23S,25S)-22,26-epimino-16beta,23-epoxy-3beta,23,27-trihydroxycholestane, which are rare naturally occurring compounds was attained by acid hydrolysis with 2 N HCl in dioxane and water (1 : 1).

Two new C(28) steroidal glycosides, tuboanosides A (1) and B (2), were isolated from the fruit of Tubocapsicum anomalum MAKINO. Their chemical structures were elucidated on the basis of spectroscopic and X-ray diffraction analysis of the p-bromobenzoyl derivative (4) of tuboanosigenin (3), the sapogenol derivative of these two glycosides. Tuboanosides have the structural peculiarity of an unusual side chain carrying an unusual linkage with a C-21 bound to C-25 on the lactone ring.

Previously, we reported an interesting reaction by which esculeogenin A [(5alpha,22S,23S,25S)-3beta,23,27-trihydroxyspirosolane], a sapogenol of tomato-saponin, esculeoside A, was easily converted into a pregnane derivative, 5alpha-pregn-16-en-3beta-ol-20-one, merely by refluxing with pyridine and water. Its chemical mechanism including air oxidation is here described.

A new homostilbene, named scillabene A (2), and two new homoisoflavones, named scillavones A (3) and B (4), were isolated from the bulbs of Scilla scilloides DRUCE (Liliaceae) along with 13 known compounds comprising a homostilbene, seven homoisoflavones, a xanthone, a lignan, and three nortriterpenes. The structures of 2-4 were characterized as 3,5,4'-trihydroxy-3'-methoxy-4-methyl-trans-stilbene, (3R)-5,7,2'-trihydroxy-3',4'-dimethoxyspiro{2H-1-benzopyran-7'-bicyclo[4,2,0]octa[1,3,5]-trien}-4-one and (3S)-3-(3,4-dihydroxybenzyl)-5-hydroxy-6,7-dimethoxychroman-4-one, respectively, on the basis of spectroscopic data and X-ray crystallographic analysis.

A new pregnane glycoside, 3-O-beta-lycotetraosyl 5alpha-pregna-3beta,26beta-diol-20-one was isolated from overripe tomato, the fruit of Lycopersicon esculentum MILL.

Three new steroid glycosides named trikamsterosides C, D and E were isolated from the underground parts of Trillium kamtschaticum PALL. (Liliaceae) along with two known 18-norspirostanol glycosides trillenosides A and B. Their chemical structures were determined on the basis of spectroscopic data and chemical evidence.