Improvement of the post-thaw qualities of Okinawan native pig spermatozoa frozen in an extender supplemented with ascorbic acid 2-O-alpha-glucoside.

The technical establishment of boar sperm cryopreservation is indispensable for effective breeding of the scarce Okinawan native pig Agu. The objective of the present study was to determine whether ascorbic acid 2-O-alpha-glucoside (AA-2G), a stable ascorbate derivative, is capable of improving the quality of cryopreserved Agu spermatozoa. Ejaculated Agu sperm frozen in an extender supplemented with 0, 100, 200, 400 or 800 microM AA-2G was thawed, and then evaluated the sperm motility and other qualities. Treatment with 200 microM AA-2G has the most beneficial effect on the sperm motility and the plasmalemma integrity after frozen-thawing among the concentrations tested (P<0.05). In particular, the incidences of total motile sperm and rapid progressive motility at 1 and 3h after incubation were markedly increased by treatment with AA-2G at 200 microM. The addition of AA-2G during cooling and freezing efficiently protected spermatozoa against the lipid peroxidation and the DNA damage. Spermatozoa frozen in the presence of AA-2G possessed significantly higher levels (P<0.05) of ATP even after thawing than those frozen without AA-2G, implying that sperm viability was effectively conserved. Furthermore, higher sperm penetrability to matured oocytes in vitro was maintained in sperm treated with AA-2G during cryopreservation. These effects were observed for all sperm derived from three individuals. These findings demonstrate that the addition of AA-2G to the freezing extender efficiently improves the post-thaw qualities of fragile Agu sperm through the protection of spermatozoa against cell damage caused by oxidative stress during cryopreservation.

Isolation of apoptosis- and differentiation-inducing substances toward human promyelocytic leukemia HL-60 cells from leaves of Juniperus taxifolia.

A chloroform extract of the leaves of Juniperas taxifolia exhibited a marked antiproliferative effect on human promyelocytic leukemia HL-60 cells at a concentration of 2.5 microg/ml. Deoxypodophyllotoxin (4) was identified in the extract as an outstanding antiproliferative compound, and five diterpenes (1-3, 5, and 6) were isolated as known compounds with weak or no cytotoxicity. These compounds were examined for their respective apoptosis- and differentiation-inducing activities toward HL-60 cells by DNA fragmentation and NBT-reducing assays, respectively. Among them, 7alpha-hydroxysandaracopimaric acid (6) was found to have a potent differentiation-inducing activity in a dose-dependent manner at 0.125-2 microg/ml (0.39-6.29 microM), together with apoptosis-inducing activity at concentrations of more than 2.5 microg/ml (7.86 microM). Deoxypodophyllotoxin (4) that exerted cytotoxic and apoptosis-inducing activities at 2 ng/ml (5 nM) did not induce differentiation at the same concentration, and the other diterpenes (1-3 and 5) showed no effect on cell differentiation, even at 5 microg/ml. It was thus demonstrated for the first time that 7alpha-hydroxysandaracopimaric acid was an effective differentiation-inducing compound toward HL-60 cells.

Neurite outgrowth-promoting active constituents of the Japanese cypress (Chamaecyparis obtusa).

In the screening of biologically active constituents from woody plants, the methanol extract of leaves of Chamaecyparis obtusa showed potent neurite outgrowth-promoting activity in neuronal PC12 cells. The ethyl acetate-soluble fraction of the methanol extract showed potent activity and was separated by means of various chromatographic methods to give the two new compounds 1 and 2, as well as 11 known lignan and sesquiterpene derivatives. The structures of the new compounds were determined to be 9-O-acetyldihydrosesamin (1) and 9-O-(11-hydroxyeudesman-4-yl)dihydrosesamin (2), respectively, in NMR studies including 2D-NMR experiments. Of the 13 compounds, the known compound hinokinin (5) and the new compound 2 showed potent neurite outgrowth-promoting activity in PC 12 cells.

New diarylheptanoids from Alnus japonica and their antioxidative activity.

In the course of research on the bioactive constituents of woody plants in the Cyugoku area of Japan, a methanol extract of the leaves of Alnus japonica were found to have strong antioxidative activity. Ethyl acetate soluble and n-buthanol soluble fractions of the methanol extract had a potent antioxidative effect. Both fractions were purified by silica gel column chromatography and HPLC using an ODS column to give four new diarylheptanoids along with known diarylheptanoids and flavonoids. These new compounds were elucidated to be 7-(3,4-dihydroxyphenyl)-5-hydroxy-1-(4-hydroxyphenyl)-3-heptanone-5-O-beta-D-xylopyranoside (1), 1-(3,4-dihydroxyphenyl)-5-hydroxy-7-(4-hydroxyphenyl)-3-heptanone-5-O-beta-D-xylopyranoside (2), 1,7-bis-(3,4-dihydroxyphenyl)-5-hydroxy-3-heptanone-5-O-[2-(2-methylbutenoyl)]-beta-D-xylopyranoside (3) and 1,7-bis-(3,4-dihydroxyphenyl)-5-methoxy-3-heptanone (4) using spectral methods and especially 1H-, 13C-NMR and 2D-NMR measurements. The isolated compounds including their main constituent, oregonin (5), were tested for antioxidative activity. Some of these compounds having two catechol structures showed potent antioxidative activity. Compounds having one catechol structure showed moderate antioxidative activity, but a peracetate of 5 having no catechol structure exhibited no antioxidative activity. Thus the catechol structure of the diarylheptanoids is indispensable for antioxidative activity.

Anti-hyaluronidase oligosaccharide derived from chondroitin sulfate a effectively reduces polyspermy during in vitro fertilization of porcine oocytes.

The present study was conducted to examine the effects of chondroitin sulfate A-derived oligosaccharide (ChSAO) on hyaluronidase activity and in vitro fertilization (IVF) parameters. The activity of hyaluronidase extracted from preincubated boar sperm was completely blocked by ChSAO at concentrations of 10 microg/ml or higher. After in vitro maturation of porcine cumulus-oocyte complexes, some oocytes were freed from their cumulus cells, and cumulus-intact or cumulus-free oocytes were inseminated with sperm in IVF medium containing various concentrations of ChSAO (0.1-100 microg/ml). In cumulus-intact oocytes, the penetration and the polyspermy rates (39% and 28%, respectively) were significantly decreased by treatment with 100 microg/ml ChSAO compared with those of oocytes treated without ChSAO (63% and 52%, respectively). On the contrary, in cumulus-free oocytes, the addition of 10-100 microg/ml ChSAO significantly reduced the polyspermy rate compared with the control (25-30% versus 53%, respectively), whereas ChSAO had no effect on sperm penetration. Interestingly, ChSAO added to IVF medium significantly decreased the number of sperm bound to the zona pellucida (ZP) of cumulus-free oocytes in a concentration-dependent manner between 0.1 and 100 microg/ml. However, ChSAO had no effect on the time course change in ZP modification after oocyte activation by electrostimulation and the incidence of the acrosome-reacted sperm. Treatment with 100 microg/ml ChSAO during IVF of cumulus-free oocytes significantly increased the proportion of development to the blastocyst stage after in vitro insemination. Therefore, the present findings indicate that hyaluronidase-inhibitory ChSAO is an efficient probe for promoting normal fertilization process in terms of an effective decrease in the incidence of polyspermy during IVF of porcine oocytes.

Protection of porcine oocytes against cell damage caused by oxidative stress during in vitro maturation: role of superoxide dismutase activity in porcine follicular fluid.

To elucidate the beneficial effects of porcine follicular fluid (pFF) added to maturation medium on the sustenance of cytoplasmic maturation responsible for the subsequent developmental competence after in vitro fertilization (IVF) of porcine oocytes, we focused on the antioxidative role of pFF in its function of protecting oocytes from reactive oxygen species (ROS)-induced cell damage. Porcine follicular fluid collected from small (2-6 mm) follicles had about 7.2-fold higher levels of superoxide dismutase (SOD) activity than that of fetal bovine serum (FBS), and this activity was markedly blocked by the CuZn-SOD inhibitor, diethyldithiocarbamate (DETC). The interruption of meiotic progression and the increasing intracellular glutathione (GSH) content throughout the maturation period, as well as an outbreak of DNA damage in oocytes and cumulus cells were difficult to detect in oocytes cultured in a medium supplemented with 10% pFF, even in the presence of ROS generated by the hypoxanthine-xanthine oxidase system, whereas cell damage encompassed by ROS was prominent in oocytes cultured with 10% FBS and 10% pFF plus 100 microM DETC. Similarly, significant enhancement to the degree of transformation of the sperm nucleus into the male pronucleus (MPN) after in vitro fertilization was shown by the addition of pFF to the maturation medium. The presence of DETC during in vitro maturation reduced the ability of oocytes to promote MPN formation to the same extent as oocytes matured with FBS. The proportion developing to the blastocyst stage was increased in oocytes that matured with pFF, but this developmental competence was significantly lowered by treatment with DETC (P < 0.05). These findings suggest that pFF plays a critical role in protecting oocytes from oxidative stress through a higher level of radical scavenging activity elicited from SOD isoenzymes, resulting in the enhancement of cytoplasmic maturation responsible for developmental competence postfertilization.

Potentiation of nerve growth factor-induced neurite outgrowth in PC12 cells by a Coptidis Rhizoma extract and protoberberine alkaloids.

A methanol extract of Coptidis Rhizoma effectively enhanced the outgrowth of neurite in PC12 cells induced by nerve growth factor (NGF). Following solvent partition and preparative HPLC, berberine was isolated as the major active compound. Berberine enhanced the proportion of neurite-bearing cells in a dose-dependent manner without cytotoxicity. Its structural relatives, palmatine and coptisine, showed a slightly weaker NGF-enhancing effect than berberine. These three alkaloids inhibited acetylcholinesterase activity at a level comparable to that of physostigmine, but this inhibition was not responsible for the potentiation of NGF-induced neurite outgrowth. It is demonstrated for the first time that protoberberine alkaloids potentiated the NGF-induced differentiation of neural cells.