Eight new labdane-type diterpenes (1-8) were isolated from the fruit of Vitex rotundifolia along with two known abietane-type diterpenoids (9, 10), and their structures were characterized on the basis of spectroscopic data and X-ray crystallographic analysis. Among them, the abietane-type diterpenoid ferruginol (9) exhibited a stronger antioxidative activity than the standard antioxidant, 3-tert-butyl-4-hydroxyanisole (BHA), using a ferric thiocyanate method.

A new phenyldihydronaphthalene-type lignan, vitedoin A (1), a new phenylnaphthalene-type lignan alkaloid, vitedoamine A (2), and a new trinorlabdane-type diterpene, vitedoin B (3), were isolated from the seeds of Vitex negundo along with five known lignan derivatives (4-8). Their chemical structures were determined mainly on the basis of NMR and MS data. Compounds 1, 2, and 4-7 showed stronger antioxidative activity than alpha-tocopherol using the ferric thiocyanate method. Compounds 1, 2, and 4-7 showed higher radical-scavenging effect on the stable free radical, 1,1-diphenyl-2-picrylhydrazyl, than L-cysteine.

Forty-three polyphenols from tea leaves were evaluated for their anti-oxidative effect against lipid peroxidation by the ferric thiocyanate method in vitro. Among these, 1,4,6-tri-O-galloyl-beta-D-glucose (hydrolyzable tannin) showed the highest anti-oxidative activity against lipid peroxidation, even stronger than that of 3-tert.-butyl-4-hydroxyanisole (BHA). The assay demonstrates that tea polyphenols, except for desgalloylated dimeric proanthocyanidins that possess a catechin structure in the upper unit and desgalloylated flavan-3-ols, and excepting theaflavin 3,3'-di-O-gallate, had more anti-oxidative activity than that of alpha-tocopherol. The chemical structure-activity relationship shows that the anti-oxidative action advanced with the condensation of two molecules of flavan-3-ols as well as with 3-O-acylation in the flavan skeleton such as that by galloyl, (3'-O-methyl)-galloyl, and p-coumaroyl groups.

Two new steroid glycosides, named trikamsterosides A and B, and a new sesquiterpenoid glycoside named trikamsesuquiside A were isolated from the underground parts of Trillium kamtschaticum PALL. along with 18 known compounds comprising 12 steroids, one sesquiterpenoid glycoside, one phenylpropanoid, one flavonoid glycoside, and three phenylpropanoid sucrose esters. Their chemical structures were determined on the basis of spectroscopic data and chemical evidence. Among them, one phenylpropanoid sucrose ester showed almost the same radical-scavenging effect on 1,1-diphenyl-2-picrylhydrazyl as that of a a-tocopherol.

Lippia triphylla (L'HER) O. KUNTZE: (Verbenaceae; common name, Lemon Verbena) is used in Peru as a spice and herb tea for the prevention of arteriosclerosis. From the aerial parts of this plant, 25 known compounds--3 phenylpropanoid glucosides, 7 flavonoids, 5 phenylethanoid glycosides, 5 lignans, 2 sesquiterpenoids, and 3 triterpenoids--were isolated, and their chemical structures were elucidated on the basis of physical and spectral data. Among them, 19 aromatic compounds were examined for their scavenging effect on the stable free radical 1,1-diphenyl-2-picrylhydrazyl--4 phenylethanoid glycosides and 5 lignans indicated a potent scavenging effect. Of note, the EC(50) values of two phenylethanoid glycosides reached almost thrice that of alpha-tocopherol.

The methanol extract of the aerial part of Tessaria integnfolia (common name: pajaro bobo), which is used as an herb for the treatment of asthnra and liver injury in Peru, showed a stronger antioxidative activity than the standard synthetic antioxidant, 3-tert-butyl-4-hydroxyanisole (BHA). From this extract, five new eudesmane-type sesquiterpenoids were isolated along with eighteen known compounds, and their structures were elucidated on the basis of MS, IH-NMR and 13C-NMR data. Among them, eleven phenolic compounds, four flavonoids, two lignans and five caffeoyl quinic acid derivatives were examined for their antioxidative activity using the ferric thiocyanate method, and nine compounds indicated a stronger antioxidative activity than the standard natural antioxidant, a-tocopherol at a concentration of 0.5 mM. Especially, two flavonoids were identified as stronger antioxidants than BHA. The scavenging effect of the phenolic compounds on the stable radical 1,1-diphenyl-2-picrylhydrazyl was examined. All tested compounds showed this scavenging effect, with the effect of five caffeoyl quinic acid derivatives and three flavonoids being almost twice or more that of a-tocopherol at a concentration of 0.01 mM.

Seven known compounds, pyrroside B (1), swertisin (2), isovitexin (3), isoswertiajaponin (4), vomifoliol (blumenol A) (5), (6S,9R)-roseoside (6) and angelicoidenol (7) were isolated from the methanol (MeOH) extract of the aerial part of Piper elongatum VAHL. and their structures were identified on the basis of physical and spectral data. In addition, the antioxidative activity of 1-4 was evaluated by the ferric thiocyanate method. All these compounds showed stronger antioxidative activity than that of ␣-tocopherol. Furthermore, the scavenging effects on 1,1-diphenyl-2-picrylhydrazyl (DPPH), the antihyaluronidase and the antityrosinase activities of 1-4, asebogenin (8), 2¢ ¢ ¢ ¢,6¢ ¢ ¢ ¢-dihydroxy-4¢ ¢ ¢ ¢-methoxydihydrochalcone (9), 3-geranyl-4-methoxybenzoic acid (10), 3-geranyl-4-hydroxybenzoic acid (11), nervogenic acid (12) and 2,2-dimethyl-6-carboxyl-8-prenyl-chromene (13), which were previously isolated from the MeOH extract were evaluated. Compounds 4, 8 and 9 showed higher radical scavenging effect than that of L-cysteine, and 4, 8 and 11 exhibited stronger inhibition effect on the activation of hyaluronidase than that of tranilast. Compound 8 indicated almost the same antityrosinase activity as that of kojic acid.

A new phenylethanoid glycoside, named acetyl forsythoside B (1), was isolated from the fruits of Callicarpa japonica Thunb. var. luxurians Rehd. (Verbenaceae) along with forsythoside B (2), brandioside (3), poliumoside (4), actioside (5), and apigenin 7-galacturonide (6). The structures of 1-6 were determined on the basis of spectroscopic data. In addition, the antioxidative activity of 1-4 and 6 was evaluated by the ferric thiocyanate method. All of the tested compounds except 6 exhibited almost the same activity as 3-tert-butyl-4-hydroxyanisole. The radical-scavenging effect of 1-6 on the stable free radical 1,1-diphenyl-2-picrylhydrazyl was also examined. Compounds 1-5 showed almost twice the activity compared to a-tocopherol.