Levels Of Coumestrol Research Articles

Effect of pea aphid and bluegreen lucerne aphid (Acyrthosiphonspp.) on coumestrol levels in herbage of lucerne (Medicago sativa)

Abstract Field and glasshouse studies showed that infestations of pea aphid (Acyrthosiphon pisum Harris) and bluegreen lucerne aphid (A. kondoi Shinji) (BGA) caused increased coumestrol levels in herbage of lucerne (Medicago sativa cv. “Wairau”). Under field conditions log coumestrol concentration (ppm) was linearly related to aphid numbers and a reduction in stem length was associated largely with aphid damage. The coumestrol levels in severely aphid-damaged herbage were high enough to impair ewe fecundity. Glasshouse studies showed that similar levels of coumestrol were found in leaf and stem tissue of aphid damaged plants and that BGA infestations caused higher coumestrol levels than similar population levels of pea aphid.

Plasma coumestrol levels and cervical mucus responses in ewes ingesting coumestan-rich feeds

The concentrations of free and conjugated coumestrol in plasma drawn from the jugular vein of ovariectomized ewes were measured during 17 days of feeding on two coumestan-rich diets. Average daily intakes (± SE) of coumestans for ewes fed on diets A and B were 952 ± 30 mg and 514 ± 1 mg respectively. There was no change in the concentration of free coumestrol in the plasma during the period of feeding of the two diets, except for the last day when the diets were interchanged. The concentration of free coumestrol appeared to be related to the amount of coumestans ingested—81 v. 37 ng/l0 ml plasma (P < 0.01) for ewes fed on diets A and B respectively. The effects of length of feeding and diet on the concentration of conjugated coumestrol were less well defined but showed similar trends.Despite the significant amounts of coumestrol in the plasma after 16 days of feeding on the two diets, the production of cervical mucus remained at basal levels. It was concluded that for the cervical mucus bioassay, ewes become refractory to coumestrol over prolonged periods of exposure.

Plasma coumestrol levels in sheep following administration of synthetic coumestrol or ingestion of medic hay (Medicago littoralis)

Administration of coumestrol to ovariectomized sheep by either intraruminal (i/r) infusion (350 mg/day) or intramuscular (i/m) injection (7.5-–25 mg/day) gave rise to mean plasma levels of 0.6-3.1 µg coumestrol per 100 ml and to near-maximal stimulation of uterine growth. In addition the plasma contained water-soluble conjugates of coumestrol, hydrolysable by molluscan ß-glucuronidase; this fraction was quantitatively more important, relative to 'free' coumestrol, following i/r infusion of coumestrol, but seemed less closely related to oestrogenic action than was "free" plasmacoumestrol. Feeding on a ration of medic hay (Medicago littoralis), supplying approximately 146 mg coumestrol and 124 mg 4´-methoxycoumestrol per day, gave rise to plasma levels of 0.5–0.7 µg "free" coumestrol and 1.2–4.0 µg conjugated coumestrol per 100 ml, and was associated with oestrogenomimetic changes in the composition of the cervical mucus. 4´-methoxycoumestrol was not detected in the plasma, which suggested that this compound had been converted to coumestrol by O-demethylation in the medic-fed sheep.

Effect of Aphid Infestation on the Coumestrol Content of Alfalfa Varieties Differing in Aphid Resistance1

The effects of pea aphid and spotted alfalfa aphid infestations on the coumestrol content of three alfalfa (Medicago sativa L.) varieties and one alfalfa synthetic were determined in plant growth chambers. The alfalfas tested ranged from very susceptible to highly resistant to both aphid species. Coumestrol from aphid‐damaged tissue was identified by chromatography and ultraviolet spectroscopy. Aphid‐damaged portions of all varieties contained elevated coumestrol levels. Undamaged plant tissue and uninfested plants generally had less than 1 ppm coumestrol. The more resistant varieties accumulated less coumestrol than the susceptible variety ‘Vernal.’ Selection in alfalfa for aphid resistance can be expected to reduce the accumulation of coumestrol which results fiom aphid damage.

Coumestrol in alfalfa as a factor in growth and carcass quality in lambs.

Four feeding trials with lambs fed varying amounts of alfalfa coumestrol are described, progressing from use of crude alfalfa meals through acetone extracts of different coumestrol potency to a final test of isolated coumestrol itself. In general, a trend toward a positive growth response to elevated coumestrol levels was obtained with wether lambs, but not with ewes. Marked increases in teat length and in seminal vesicle and pituitary weights were obtained in animals fed the higher levels of coumestrol. Organoleptic tests consistently demonstrated improved tenderness and juiciness scores from lamb roasts from animals fed high-coumestrol diets. The response from coumestrol, as compared with that of DES, and the implication of a number of dietary and extraneous factors upon the bio-potency of dietary coumestrol are discussed.

Wether bioassay of annual pasture legumes. III. The oestrogenic potency of dry subterranean clover pastures, and of leaf blade and petiole in the green state

Late summer pastures of nine strains of subterranean clover had very low oestrogenic activity as assessed by wether teat length bioassay. Only the Dwalganup variety had measurable activity which may have been due mainly to moderate levels of coumestrol in the various dry plant fractions. The activity of green leaf blade of the Yarloop strain was about nine times as great as that of the petioles. Possible agronomic implications of this finding are discussed.