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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.

Fifty-one tannins and forty-one flavonoids isolated from Oriental medicinal herbs were evaluated for their antioxidant ability with a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-generating system. The results showed that tannins and certain flavonoids are potential free-radical scavengers, and that their activity against the DPPH radical is closely associated with their chemical structure. A comparison of the two classes of compounds showed that tannins have more potential than flavonoids because almost all the tannins demonstrated significant scavenging action within a low concentration range, whereas the activity of flavonoids varied distinctively among the different compounds. An increase of galloyl groups, molecular weight, and ortho-hydroxyl structure enhanced the activity of tannins, whereas the number and position of hydroxyl groups were important features for the scavenging of free radicals by flavonoids. Moreover, it appeared that when the free hydroxyl group was methoxylated or glycosylated, the inhibitory activity was obviously decreased or even abolished.

Summary A study was conducted to clarify whether magnesium lithospermate B ameliorates cisplatin-induced renal injury in terms of lactate dehydrogenase and malondialdehyde leakage from LLC-PK 1 cells in culture. Magnesium lithospermate B was shown to suppress the cytotoxicity of cisplatin, the suppressive effect increasing with the dose of magnesium lithospermate B.

Two new ellagitannins, named syzyginins A and B, were isolated from the leaves of clove ( Syzygium aromaticum. ). Syzyginin A was characterized as 1,2,3- tri -O- galloyl -4,6-(S)- tergalloyl -β- d -glucopyranose . Suzyginin B was a novel hydrolysable tannin possessing a new aromatic acyl group, syzygyl, which has a dibenzo-1,4-dioxin structure probably derived from a tergalloyl group. Structures were established on the basis of chemical and spectroscopic evidence.

Thirty-eight tea polyphenols were evaluated for their inhibitory effect against HIV replication in H9 lymphocyte cells. 8-C-Ascorbyl (−)-epigallocatechin (13) and theasinensin-D (32) demonstrated relatively potent anti-HIV activity with EC50 values of 4 and 8 μg/mL and therapeutic indexes of 9.5 and 5, respectively.

大黄の向精神作用について, 化学的, 行動薬理学的及び神経化学的検討を行い, 下記の結論を得た。1. 大黄の向精神作用成分は, RG-タレニンである。2. 大黄の向精神作用は, 典型抗精神病薬の作用によく一致するが, 行動毒性を伴わない特長がある。これは, カタレプシーなどを惹起しないこと, また脳内ドパミン神経系の黒質―線条体路に対する影響が少ないことから立証された。

A study was conducted to clarify whether extracts of Wen-Pi-Tang and its component crude drugs ameliorate renal cellular injury by assaying lactate dehydrogenase and malondialdehyde leakage from LLC-PK(1) cells in culture. The cells were cultured with various concentrations of the samples under two sets of conditions: routine and hypoxia-reoxygenation. The results demonstrated that Wen-Pi-Tang, Rhei rhizoma, Glycyrrhizae radix exerted marked protective effects on the cells; Ginseng radix showed moderate activity, whereas Zingiberis rhizoma and Aconiti tuber had virtually no such effect. Two pure compounds, epicatechin 3-O-gallate and licochalcone A isolated from Rhei rhizoma and Glycyrrhizae radix, respectively, exerted the same marked effects as the parent crude drugs. In the light of these findings, we concluded that Wen-Pi-Tang and its major components protect renal epithelial cells against injury mediated by hypoxia-reoxygenation and/or prevent such injury. The primary mechanism of these effects appeared to be antilipid peroxidant activity present in the preparation.

The levels of urea nitrogen, creatinine, methylguanidine and guanidinosuccinic acid, which accumulate in blood in parallel with the progress of renal failure after adenine administration, were decreased significantly in rats given Galla Rhois, Moutan Cortex or Paeoniae Radix extract. Administration of Galla Rhois extract was found to be more effective than the other two crude drugs in decreasing the uraemic toxin parameters. A uraemic toxin-decreasing effect similar to that of crude drug was also obtained using 1,3,6-tri-O-galloyl-β-D-glucopyranose and 1,2,3,4,6-penta-O-galloyl-β-D-glucopyranose.

Previously we have isolated the quaternary base alkaloids, magnoflorine and phellodendrine, from Phellodendri Cortex (cortex of Phellodendron amurense Rupr., Rutaceae) as the biologically active principles to suppress local graft-versus-host (GvH) reactions in mice. In this paper, we focus on phellodendrine. Phellodendrine suppressed local semisyngeneic GvH reactions and systemic allogeneic GvH reactions in X-ray irradiated recipient mice. Phellodendrine also suppressed the induction phase of sheep red blood cell (SRBC)-induced delayed type hypersensitivity in mice and tuberculin-induced delayed type hypersensitivity in guinea pigs, but did not suppress the effector phase of these reactions. Surprisingly, phellodendrine, unlike prednisolone and cyclophosphamide, did not affect antibody production in mice to SRBC. Phellodendrine was expected to be a valuable new type of immunosuppressor against the cellular immune response.

Nine crude drugs containing tannins were selected in order to examine their actions on rats with renal failure. The levels of urea nitrogen, creatinine (Cr), methylguanidine (MG) and guanidinosuccinic acid (GSA) were decreased markedly and significantly in rats given Ephedrae Herba. Chebulae Fructus and Geranii Herba produced the same effect on uraemic toxins as that of Ephedrae Herba. MG was significantly decreased by all tannin-containing crude drugs. However, there were no particular changes in these parameters after administration of non-tannin-containing crude drugs. The levels of urea nitrogen, Cr, MG and GSA showed a tendency to be increased in rats given Rehmanniae Radix, Coptidis Rhizoma, Scutellariae Radix and Alismatis Rhizoma, but MG was decreased significantly in rats given Bupleuri Radix. Non-tannin compounds also produced no significant decreases in the levels of uraemic toxins.

A new dimeric ellagitannin, bischofianin, was isolated from the leaves of Bischofia javanica, together with five known tannins. The structure was elucidated on the basis of spectroscopic and chemical evidence.

We previously reported that Wen-Qing-Yin (Unsei-in), a traditional Chinese blended medicine, inhibited the induction phase of various kinds of delayed type hypersensitivity (DTH) and local graft-versus-host (GvH) reactions, but did not affect humoral immune responses or the effector phase of DTH in experimental animals. In another report, we demonstrated that Phellodendri Cortex (bark of Phellodendron amurense Rupr. Rutaceae) was a component having the most potent suppressive effect on the cellular immune response among the 8 medical plants composing Unsei-in. In the present study, we isolated OB-1 and OB-5 from Phellodendri Cortex as the biologically active principles to suppress local GvH reactions in mice. OB-1 and OB-5 are quaternary base alkaloids known as magnoflorine and phellodendrine, respectively. They suppressed the local GvH reaction, when given i.p. to the host mice at 5-20 mg/kg for 8 consecutive days from the day of spleen cell transfer to cause the reaction. Both OB-1 and OB-5 suppressed picryl chloride-induced delayed type hypersensitivity (PC-DTH) when given i.p. to mice at 10 and 20 mg/kg for 5 consecutive days from the day of the sensitization, but did not suppress it when given at the time of the challenge. These results suggest that OB-1 and OB-5 suppress the induction phase but not the effector phase of the cellular immune response. They are expected to have a value as a new type of immunosuppressor.

The effects of magnesium lithospermate B on blood pressure were examined in spontaneously hypertensive rats. Systolic, mean and diastolic blood pressures were decreased after magnesium lithospermate B administration, whereas the urinary levels of kallikrein, prostaglandin E 2 , sodium and potassium were increased. The mechanisms of the depressor action of magnesium lithospermate B were discussed on the basis of these findings

Callus was induced from the fruit galls of Actinidia polygama and the regenerated plants from the callus tissue were cultured. The formation of triterpenoids in the callus was confirmed. Eight triterpenoids containing two new ones were isolated from the callus. The triterpenoid composition found in the callus tissue was compared with those in the regenerated and natural plants. The differences in the metabolic ability of the callus tissue and regenerated plants are also discussed.

A study was conducted to investigate the effects of magnesium lithospermate B on the uraemic symptoms and development of hypertension in rats with adenine-induced renal failure. Chronic administration of 10 mg/kg body weight/day magnesium lithospermate B significantly reduced serum urea nitrogen, creatinine, methylguanidine, guanidinosuccinic acid and inorganic phosphate, accompanied by increased urinary excretion of urea, creatinine and electrolytes. In addition, renal tissue blood flow was significantly increased and mean blood pressure significantly decreased in the magnesium lithospermate B-treated group compared with the control group. These results confirm that chronic administration of magnesium lithospermate B to rats with adenine-induced renal failure ameliorates the uraemic symptoms and development of hypertension by improving renal haemodynamics and electrolyte metabolism.

Two Dan Shen preparations commercially available in China were given intraperitoneally to rats with renal failure in order to investigate their effects on blood and urine components. In rats given an injection of compound Dan Shen composed of Dan Shen and Jiang Xiang, effects similar to those found after administration of magnesium lithospermate B (the active constituent of Dan Shen) alone were observed. In contrast, in rats given noncompound Dan Shen containing almost no magnesium lithospermate B as revealed by high-performance liquid chromatographic analysis, there was a significant decrease only in the blood levels of urea nitrogen and inorganic phosphorus.

Five new ellagitannins, platycaryanins A (27), B (26), C (30), and D (25), and platycariin (31), and a new complex tannin, strobilanin (32), have been isolated from the fruits and bark of Platycarya strobilacea SIEB. et ZUCC. (Juglandaceae), together with twenty-six known compounds. On the basis of spectroscopic and chemical evidence, platycaryanins A, B and C, and platycariin have been characterized as the ellagitannins having a tergalloyl ester group, while platycaryanin D was found to be an unusual ellagitannin possessing (R)-hexahydroxydiphenoyl esters at the glucopyranose 2, 3- and 4, 6-positions. During these chemical studies, re-examination of the similar ellagitannins, alnusnins A and B, which were previously reported from Alnus sieboldiana, led us to revise their structures to 29 and 28, respectively, in which the tergalloyl group forms a lactone ring. Furthermore, biomimetic conversion of ellagitannins having a glucopyranose core into C-glycosidic ellagitannins was successfully achieved for the first time, and the reaction was applied to the structure elucidation of platycariin (31).

From the dried leaves of Syzygium aromaticum MERR. et PERRY (Myrtaceae), eleven new compounds, i.e., eugenol 4-O-β-D-(6'-O-galloyl)glucopyranoside (17), 2-methyl-5, 7-dihydroxychromone 8-C-β-D-glucopyranoside (18) and its 6'-O-gallate (19), 2, 4, 6-trihydroxyacetophenone 3-C-β-D-glucopyranoside (20) and its 2'-O- (21), 6'-O- (22), 2', 3'-di-O- (23), 2', 6'-di-O- (24), 2', 3', 6'-tri-O- (25), 2', 3', 4', 6'-tetra-O-gallate (26) and 2', 3'-di-O-galloyl-4', 6'-O-(S)-hexahydroxydiphenoyl ester (27) were isolated, together with sixteen known tannins and related compounds. The structures of these compounds were established on the basis of spectroscopic and chemical evidence.

Chemical examination of the leaves of Rubus lambertianus Seringe (Rosaceae) has led to the isolation of four new ellagitannins, which were characterized on the basis of chemical and spectroscopic evidence to be dimers [lambertianins A (6) and B (7)], a trimer [lambertianin C (8)] and a tetramer [lambertianin D (10)], all having sanguisorbic acid ester group(s) as linking unit(s) between glucopyranose moieties. Furthermore, HPLC analyses of fifteen Rubus species collected in Japan and Taiwan revealed that the trimer (8) and the tetramer (10), together with sanguiin H-6 (1), occur widely in these species.

The structue of cercidinin A, an ellagitannin isolated from the bark of Cercidiphyllum japonicum, was revised to 1, 2, 6-tri-O-galloyl-3, 4-(R)-hexahydroxydipenoyl-β-D-glucose by two-dimensional NMR spectral analysis. Cercidinin A represents the first ellagitannin possessing a hexahydroxydiphenoyl group at the 3, 4-positions of a modified 4C1-glucopyranose core.

Fifty-seven tannins and related compounds, including gallotannins, ellagitannins, and condensed and complex tannins, were evaluated for their cytotoxicities against human tumor cell lines, including malignant melanoma, lung carcinoma, ileocecal adenocarcinoma, epidermoid carcinoma, malignant melanoma, and medulloblastoma cell lines. Among them, chebulagic acid [1], geraniin [2], sanguiin H-11 [3], 4,5-di-O-galloylquinic acid [12], 1,3,4,5-tetra-O-galloylquinic acid [15], 1(beta)-O-galloylpedunculagin [24], furosin [29], castalagin [38], sanguiin H-2 [34], vescalagin [39], grandinin [40], phyllyraeoidin A [42], (-)-epicatechin 3-O-gallate [50], cinnamtannin B2 [55], and acutissimin A [56] exhibited moderate selective cytotoxicity against PRMI-7951 melanoma cells with ED50 values in the range of 0.1-0.8 microgram/ml. Selective cytotoxicities against the melanoma cells were also observed for strictinin [22], pedunculagin [23], eugeniin [25], elaeocarpusin [28], punicacortein C [37], casuarinin [41], sanguiin H-6 [43], procyanidin B-2 3,3'-di-O-gallate [51], procyanidin C-1 3,3',3"-tri-O-gallate [52], and cinnamtannin B1 [54] with ED50 values of 1-4 micrograms/ml. All of the tannins were found to be inactive (greater than 10 micrograms/ml) against lung carcinoma (A-549), ileocecal adenocarcinoma (HCT-8), epidermoid carcinoma of nasopharnyx (KB), and medulloblastoma (TE-671) tumor cells.

Two new hydrolysable tannins, alnusjaponins A and B, were isolated from the leaves of Alnus japonica , along with 12 known hydrolysable tannins and related compounds, namely 5- O -galloyl-(−)-shikimic acid, 2,3-( S )-hexahydroxydiphenoyl- d -glucose, 4,6-di- O -galloyl- d -glucose, 1,4-di- O -galloyl-β- d -glucose, 4,6-( S )-valoneoyl- d -glucose, strictinin, gemin D, pedunculagin, praecoxin A, flosin A, stachyurin and casuarinin. The structures of alnusjaponins A and B were elucidated on the basis of spectral and chemical evidence as dimeric ellagitannins consisting of pedunculagin and strictinin moieties in which the mode of linkage is different.

A study was performed to investigate the haemodynamic effects of magnesium lithospermate B in rats with renal failure. Urinary excretion of sodium and potassium was significantly increased by administration of magnesium lithospermate B. Blood pressure was significantly lower in the magnesium lithospermate B-treated group, compared with the control group. In addition, renal tissue blood flow and cerebral blood flow were significantly higher in the magnesium lithospermate B-treated group, with significantly reduced renal vascular resistance and cerebral vascular resistance compared with the control group. These results confirm that magnesium lithospermate B reduces renovascular hypertension by improving urinary electrolyte excretion and haemodynamics.

Chemical examination of the leaves of Pithecellobium lobatum has led to the isolation and characterization of five flavan-3-ol derivatives including new flavan-3-ol gallates, gallocatechin 3′- and 4′-O-gallates and gallocatechin 7,3′- and 7,4′-di-O-gallates (almost racemic), which occur as equilibrium mixtures. Examination of the pods afforded three proanthocyanidins (procyanidins B-3 and B-4 and prodelphinidin B-1), together with flavan-3-ols.

A novel ellagitannin, hirsunin, was isolated from the leaves of Alnus hirsuta var. microphylla and the structure which consists of diarylheptanoid glycoside (oregonin) and ellagitannin (praecoxin A) moieties connected through an ester linkage has been elucidated. Furthermore, the occurrence of the seven known hydrolysable tannins, pedunculagin, praecoxin A, 1,2,6- and 1,4,6-tri- O -galloyl-β- d -glucoses, 1-desgalloyleugeniin, 1-desgalloylrugosin F, and rugosin F, along with oregonin and gentisic acid 5- O -β- d -(6′- O -galloyl)-glucopyranoside has also been demonstrated.

The dehydroellagitannins having a dehydrohexahydroxydiphenoyl ester group in the molecule were found to undergo highly regio- and stereospecific condensation with acetone in the presence of ammonium ion under almost neutral conditions. This reaction was successfully applied to high-performance liquid chromatographic analysis to detect the dehydroellagitannins in the plant extract. Furthermore, the reactions of the acetone condensates with L-cysteine methyl ester were examined, and appear to be applicable to structural studies of dehydroellagitannins.

Lagerstannins A (6), B (11) and C (8), ellagitannins having a gluconic acid core, have been isolated from the fruits and leaves of Lagerstroemia speciosa (L.) PERS. (=L. flos-reginae RETZ.)(Lythraceae). On the basis of chemical and spectroscopic evidence, their structures were established as 2, 3;4, 6-bis-O-(S)-hexahydroxydiphenoyl-D-gluconic acid (6), 2, 3, 5-O-(S, R)-flavogallonyl-4, 6-O-(S)-hexahydroxydiphenoyl-D-gluconic acid (11), and 5-O-galloyl-4, 6-O-(S)-hexahydroxydiphenoyl-D-gluconic acid (8), respectively. Furthermore, the structure of an ellagitannin, punigluconin, previously isolated from the bark of Punica granatum L., was revised as 2, 5-di-O-galloyl-4, 6-O-(S)-hexahydroxy-diphenoyl-D-gluconic acid (10), based on spectral re-examination.

Continuing chemical examination of black tea has led to the isolation of three novel fermentation products, theogallinin (1), theaflavonin (10) and desgalloyl theaflavonin (11). The structure of 1 was established on the basis of physico-chemical evidence to be a condensation product linked through pyrogallol-pyrogallol rings in theogallin (2) and (-)-epigallocatechin 3-O-gallate (3), while 10 and 11 were characterized as B, B'-linked bisflavonoids formed by an oxidative coupling of isomyricitrin (12) and tea catechins [3 and (-)-epigallocatechin (4)]. Furthermore, high performance liquid chromatography analyses of the changes of tea polyphenols during fermentation have revealed that original tea catechins are more rapidly transformed by endogenous phenol oxidase to theasinensins (e.g.6, 8) and oolongtheanin (13) than the formerly known black tea pigments, theafiavins.

To evaluate the antihypertensive effect of magnesium lithospermate B isolated from Salviae miltiorrhizae radix, determinations of blood pressure and urinary excretions of sodium, potassium, prostaglandin E2 (PGE2) and kallikrein, which have been proposed to play an important role in the regulation of blood pressure, were made in rats with sodium-induced hypertension and renal failure. In rats given magnesium lithospermate B, blood pressure was significantly decreased, whereas urinary excretion of electrolytes was significantly increased. Urinary PGE2 excretion following administration of magnesium lithospermate B increased as the dose of the compound was stepped up. The activity of kallikrein in urine was also increased by the treatment. From these results, the blood pressure-lowering action of magnesium lithospermate B may be due in part to enhancement of the kallikrein-prostaglandin system.

Flavonol glycosides, icariin, epimedin B and C, contained in six Epimedium species were qualitatively and quantitatively analysed by HPLC. Significant differences in the flavonol glycoside content were found between species. The highest accumulation of flavonol glycoside occurred about two months after germination. p]Electrophoretic analyses of isozymes, phosphoglucomutase, phosphoglucose isomerase, glutamate oxaloacetate transaminase, 6-phosphogluconate dehydrogenase, isocitrate dehydrogenase and glutamate dehydrogenase, were performed. E. diphyllum and E. sagittatum can be distinguished from other species. It is evident from this analysis that E. setosum and E. grandiflorum var. higoense are closely related to E. diphyllum, E. sempervirens and E. grandiflorum. These results show that the electrophoretic analysis of isozymes supports the morphological classification of Epimedium species in Japan.

A chemical examination of Magnoliae Cortex produced in China (Magnolia officinalis REHD. et WIL S., Magnoliaceae) has led to the isolation of eighteen new lignans and related compounds [four monoterpenyl-lignans : piperitylmagnolol (3), dipiperitylmagnolol (4), piperitylhonokiol (5) and bornylmagnolol (6); seven lignans : magnaldehydes B(8), C(9), magnolignans A(10), B(11), C(12), D(13) and E(14); three norlignans : magnatriol B(16), magnaldehydes D(17) and E(18); and four dilignans : magnolignans F(19), G(20), H(21) and I(22)], together with randainal (7), randaiol (15), sinapic aldehyde, syringaresinol, syringaresinol 4'-O-β-D-glucopyranoside and 6'-O-methylhonokiol. Their structures were determined by the chemical and spectral methods.

A chemical investigation of tannins in three Euphorbia species (E. helioscopia, E. jolkini and E. supina) has led to the isolation and characterization of four new hydrolyzable tannins, named supinanin (15), euphorscopin (16), euphorhelin (17) and jolkianin (18), together with fourteen known compounds (1-14). On the basis of chemical and spectroscopic evidence, the structures of supinanin and euphorscopin were established as 1, 3, 6-tri-O-galloyl-2, 4-(S)-dehydrohexahydroxydiphenoyl-β-D-glucose (15) and 1, 3-(S)-dehydrohexahydroxydiphenoyl-2-O-galloyl-4, 6-(S)-hexahydroxydiphenoyl-β-D-glucose (16), respectively. Euphorhelin and jolkianin were characterized as dimeric hydrolyzable tannins (17 and 18, respectively), in which two glucopyranose units are linked via valoneoyl and dehydrodigalloyl groups, respectively, and each molecule possesses a dehydrohexahydroxydiphenoyl group.

Further chemical work on tannins in the leaves of Lagerstroemia flos-reginae RETZ. (Lythraceae) has resulted in the isolation of new monomeric (flosin B) and dimeric ellagitannins (reginins C and D), together with pterocarinin A (1) and 5-desgalloylpterocarinin A (2). On the basis of chemical and spectroscopic evidence, the structure of flosin B was determined to be a C-glycosidic ellagitannin (3) possessing a valoneic acid dilactonyl group, while reginins C and D were characterized as dimeric ellagitannins (6 and 10, respectively), in which a pedunculagin moiety is connected to pterocarinin A and casuarinin [the C-1 epimer of stachyurin (5)] moieties, respectively, through a carbon-to-oxygen bond.

Two novel hydrolyzable tannins, alienanins A (5) and B (13), have been isolated from the leaves of Quercus aliena GLUME (Fagaceae), and their structures were elucidated on the basis of chemical and spectroscopic evidence to be dimeric C-glycosidic ellagitannins in which the hexahydroxydiphenoyl ester group is linked to the C-glycosidic C-1 atom through a carbon to carbon linkage. In addition, the structure elucidation of the monomeric C-glycosidic ellagitannin, epipunicacortein A (1), is also described briefly.

Magnesium lithospermate B and adenine were given simultaneously to rats p.o. in order to investigate their renal effects. In rats given magnesium lithospermate B at a dose of 5 mg/kg body weight/day for 12 or 24 days, glomerular filtration rate, renal plasma flow and renal blood flow were increased significantly. A significant increase in renal function parameters was also found in rats given 10 mg of magnesium lithospermate B. Urinary excretion of prostaglandin E2 was increased by administration of magnesium lithospermate B, while those of 6-keto-prostaglandin F1 alpha and thromboxane B2 were unaffected at a dose of 5 mg or 10 mg/kg body weight/day for 12 or 24 days. The activity of kallikrein in urine increased markedly and significantly in rats given 5 or 10 mg of magnesium lithospermate B for 12 or 24 days. From these results, it seems that magnesium lithospermate B increases renal function by improving the renal circulatory state through activation of kallikrein and promotion of prostaglandin E2 production.

Continuing chemical examinatino on tannins of Combretaceous Plants has led to the isolation of four new ellagitannins, calamansanin and calamanins A, B, and C, together with ten structurally known tannins and related compounds, from the leaves of Terminalia calamansanai (BLANCO) ROLFE. On the basis of chemical and spectroscopic evidence, the structures of calamansanin and calamanin A were established as 1, 6-di-O-galloyl-2, 3-O-(S)-hexahydroxydiphenoyl-4-O-(S)-flavogallonyl-α-D-glucose (11) and 1-O-galloyl-2, 3-O-(S)-hexahydroxydiphenoyl-4, 6-O-(S)-valoneoyl-α-D-glucose (14), respectively, while calamanin B and calamanin C were characterized as dimeric and trimeric ellagitannins 15 and 16, respectively, in which the glucose units are linked through valoneoyl group(s).

Urinary excretion of prostaglandin E2 showed a significant increase following administration of magnesium lithospermate B [1] in rats with renal failure. In contrast, that of thromboxane B2 showed a significant decrease, indicating the improvement of renal failure.

A chemical examination of the tannin ingredients in the leaves of the wood oil tree, Aleurites fordii HEMSLEY (Euphorbiaceae), has led to the isolation of three new ellagitannins named aleurinins A (4), B(5) and C(6), together with corilagin (1), geraniin (2) and chebulagic acid (3). on the basis of chemical and spectroscpic evidence, the structures of aleurinins A (4) and B (5) have been established as ellagitannins possessing a novel cyanopropylene alcohol glucoside core, while aleurinin C (6) has been characterized as an ellagitannin based on a hydroxyacetone glucoside core.

A chemical examination of mylobalans (the fruits of Terminalia chebula RETZ., Combretaceae) has led to the isolation and characterization of punicalagin (1), terflavin A (2) and a new ellagitannin named terchebulin (3), which possesses a anovel tetraphynylcarboxylic acid (terchebulic acid) moiety. Furthermore, from the leaves of T. chebula, a series of biogenetically related hydrolyzable tannins, terflavins B (7), C (9) and D (10), punicalagin (1) and punicalin (8), have been isolated and structurally elucidated. The concomitant isolation of terflavins A (2) and B (7) provides biogenetic evidence that the tervhebulic acid moiety is derived by an oxidative carbon-oxygen coupling of adjacent flavogallonic acid and gallic acid esters.

Together with eleven known compounds (1-11), seven new tannins, 3-desgalloylterchebin (12), macaranins A, B and C, and macarinins A, B and C, have been isolated from the leaves of Macaranga sinensis (BAILL.) MUELL.-ARG. (Euphorbiaceae). Macaranins A (14), B (13) and C (17) have been determined on the basis of chemical and spectroscopic evidence to be hydrolyzable tannins possessing a novel acyl group (macaranoly group) at the 3, 6-positions of the 1C4 (or skew boat) β-D-glucopyranose ring, while macarinins A (18), B (15) and (16) were characterized as those having a tergalloyl group at the same positions.

Proanthocyanidins containing flavan-3-ol (epiafzelechin and epicatechin) units with an abnormal 2S-configuration have been isolated from the pods of Cassia fistula L. and the bark of C. javanica L. (Leguminosae), together with common flavan-3-ols and proanthocyanidins. The structures of these compounds have been established on the basis of chemical and spectroscopic evidence

The structures of the C-glycosidic ellagitannins, castalagin, vescalagin, casuarinin and stachyurin, have been revised to 1-4 respectively, on the basis of two-dimensional nuclear Overhauser effect (NOE) spectroscopy and NOE difference spectroscopy. Furthermore, the structures of some related C-glycosidic tannins were re-examined by using similar techniques, and it was concluded that the configuration at the glucose C-1 position in all hitherto known C-glycosidic tannins must be revised.

A chemical examination of the polyphenolic constituents of the fern, Dicranopteris pedata HOUTT., has led to the isolation of eight new proanthocyanidins possessing a doubly-linked (A-type) unit, together with known flavan-3-ols and proanthocyanidins. On the basis of chemical and spectroscopic evidence, they are characterized as epiafzelechin-(4β→8, 2β→O→7)-eniafzelechin-(4α→8)-epiafzelechin(8), epicatechin-(4β→8, 2β→O→7)-epiafzelechin-(4α→8)-epiafzelechin(9), epiafzelechin-(4β→8, 2β→O→7)-epizfzelechin-(4α→8)-epicatechin(10), epiafzelechin-(4β→8, 2β→O→7)-epicatechin-(4α→8)-epicatechin (11), epicatechin-(4β→8, 2β→O→7)-epiafzelechin-(4α→8)-epicatechin (12), epicatechin-(4β→8, 2β→O→7)-epicatechin-(4α→8)-epiafzelechin (13), epicatechin-(4β→8, 2β→O→7)-epicatechin-(4α→8)-epigallocatechin (14) and epiafzelechin-(4β→8)epicatechin-(4β→8, 2β→O→β→7)-epicatechin-(4α→8)-epicatechin (15).