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Biomedical subjects

H H Fong

Publications and source records attributed to H H Fong.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

Effect of (+)-gossypol on fertility in male hamsters.

(+)-Gossypol was isolated from the bark of Thespesia populnea and tested for its ability to inhibit the fertility of male hamsters. Male hamsters of proven fertility were treated orally for 54 days with 40 mg/kg of (+)-gossypol, 40 mg/kg of racemic gossypol, or 5% gum acacia (vehicle control) and were mated with estrous female hamsters during the fourth and seventh weeks of treatment. Both the control and the (+)-gossypol-treated animals exhibited normal fertility throughout the experiment. The racemic gossypol-treated animals were infertile when evaluated during both the fourth and seventh weeks of treatment. Morphologic examination of the testicular tissue could not explain the loss of fertility. These data demonstrate the inability of (+)gossypol to decrease male fertility and suggest that the activity of racemic gossypol may be due primarily to the presence of the (-) optical isomer.

Animals↗
PubMedDate not supplied

Inhibition of LDH-X by gossypol optical isomers.

Racemic gossypol is an effective male antifertility agent in several mammalian species. However, (+)-gossypol is not an effective male antifertility agent in the rat or the hamster. Previous studies have demonstrated the ability of racemic gossypol to inhibit the testis-specific LDH-X enzyme derived from various mammalian species and have suggested LDH-X as the potential site of gossypol antifertility action. In the present study, the effects of racemic gossypol and the (+) and (-) optical isomers of gossypol on LDH-X derived from rat and hamster testicular cytosol are compared to determine if there is any correlation between the in vitro inhibition of the LDH-X enzyme and in vivo antifertility effects. Both optical isomers of gossypol as well as racemic gossypol inhibit rat and hamster testicular cytosolic LDH-X activity. Inhibition of hamster testicular cytosolic LDH-X activity by (-)-gossypol was less than by either racemic gossypol or (+)-gossypol. Based on the previous reports of racemic gossypol inhibition of LDH-X, therefore, it cannot be simply concluded that LDH-X is the specific site of antifertility action of gossypol since, in the present study, (+)-gossypol, which is not an effective male antifertility agent, also inhibited rat and hamster testicular cytosolic LDH-X.

Animals↗
PubMedDate not supplied

Biological and phytochemical investigation of plants XV. Pteryxia terebinthina var. terebinthina (Umbelliferae).

Aqueous extracts of Pteryxia terebinthina var. terebinthina were shown to possess antiarrhythmic activity. A novel furanocoumarin, pterybinthinone, the known coumarins pteryxin and umbelliferone, and sucrose were isolated from this plant. Attempts to re-isolate a structurally undefined, defibrillatory substance by means of a published protocol were unsuccessful.

Aconitum↗
PubMedDate not supplied

Uterotonic effect of Evodia rutaecarpa alkaloids.

Rutaecarpine (1) and dehydroevodiamine (2) were isolated from the unripe fruit of Evodia rutaecarpa. In vitro uterotonic assay on rat uterus showed both alkaloids to be active. Dehydroevodiamine was further shown to be active in the in vivo uterotonic assay using rats as the animal model. Reference evodiamine hydrochloride (3) was also evaluated and found to be devoid of uterontonic activity at the doses administered.

Alkaloids↗
PubMedDate not supplied

Pulcherralpin, a new diterpene ester from Caesalpinia pulcherrima.

From the stems of Caesalpinia pulcherrima, the new cassane-type diterpene ester pulcherralpin (1) has been isolated and characterized. The structure of 1 was established through spectroscopic studies, including the 1H-1H homonuclear and 1H-13C heteronuclear correlation studies.

Acetylation↗
PubMedDate not supplied

Irisones A and B: two new isoflavones from Iris missouriensis.

Two new isoflavones, irisones A and B, together with the known compound, 5,7-dihydroxy-2',6-dimethoxy isoflavone, were isolated from the roots of Iris missouriensis. With the help of 2D-homonuclear-J-correlation and 2D-nOe experiments the structure of irisone A was deduced to be 5-hydroxy-2'-methoxy-6,7-methylenedioxy isoflavone. The structure of irisone B was elucidated by spectral analyses as 2',5-dihydroxy-6,7-methylenedioxy isoflavone and was confirmed by chemical conversion to irisone A.

Animals↗