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PubMed2004

In vitro inhibitory effect of gossypol from gossypol-acetic acid, and (+)- and (-)-isomers of gossypol on the growth of Edwardsiella ictaluri.

AIM: This study was conducted to evaluate the toxic effect of gossypol from gossypol-acetic acid, and (+)- and (-)-isomers of gossypol on the growth of Edwardsiella ictaluri. METHODS AND RESULTS: Inhibitory effect of various concentrations of gossypol on the growth of E. ictaluri was determined. Bacterial recovery was performed by preincubation of bacteria in medium containing various concentrations of gossypol and subsequent activation of bacteria by inoculating on gossypol-free plates. Concentrations of racemic gossypol, (+)-gossypol and (-)-gossypol of 1.5 microg ml(-1) or higher significantly reduced the number of bacterial colonies compared with that of the control. The growth of E. ictaluri was completely inhibited on agar plates supplemented with 3 microg ml(-1), regardless of the forms of gossypol. The inhibitory effect of (+)-gossypol was higher than that of (-)-gossypol or gossypol-acetic acid. Recovery of E. ictaluri was <50% for all three forms of gossypol at concentrations of 5 microg ml(-1). Bacterial recovery remained relatively constant (6.5%) at gossypol concentrations from 10 to 100 microg ml(-1). Complete killing of E. ictaluri was not reached at gossypol levels up to 100 microg ml(-1). CONCLUSION: Gossypol-acetic acid, and (+)- and (-)-optical isomers have anti-bacterial effect against E. ictaluri. The results suggest the action is bacteriostatic rather than bactericidal. SIGNIFICANCE AND IMPACT OF THE STUDY: The therapeutic effect of gossypol against E. ictaluri may be useful in controlling enteric septicaemia of catfish.

Anti-Bacterial Agents↗

PubMed1984

Comparative in vitro spermicidal effects of (+/-)-gossypol, (+)-gossypol, (-)-gossypol and gossypolone.

The comparative in vitro spermicidal effects of (+)-gossypol, (-)-gossypol and (+/-)-gossypol were evaluated on the spermatozoa of human, monkey, rabbit, mouse, rat and hamster. The spermicidal effects of gossypol isomers were also compared with those of gossypolone, which is a proposed major metabolite of gossypol. Gossypol isomers and gossypolone were all spermicidal. (+)- and (-)-Gossypol demonstrated spermicidal activities at the same concentration at which (+/-)-gossypol shows spermicidal effects on the spermatozoa of all species tested. However, gossypolone was less potent than the gossypol isomers. The spermicidal action of gossypol may be a nonspecific effect unrelated to the antifertility mechanism of orally administered gossypol, since (+)-gossypol which is not an effective male antifertility agent also showed the equivalent spermicidal effect to that of (+/-)-gossypol.

Animals↗

PubMedDate not supplied

Studies on the male antifertility agent--gossypol acetic acid. III. Effect of gossypol acetic acid on rat testis.

Gossypol acetic acid at the dose of 5 mg/rat/day for 2 and 4 weeks did not cause any significant effect on the body weight, testis, epididymis, seminal vesicle and prostate weight, nor gossypol treatment had any significant effect on the activities of acid phosphatase and succinic dehydrogenase in the testis. Changes in the testis ATPase activity were, however, significant after gossypol treatment. During the course of present investigations no effect of gossypol treatment on 3H thymidine incorporation into DNA of testicular cells was observed, nor there were any changes in the DNA and total protein content of the testis after gossypol treatment. Gossypol treatment did not cause any effect on the plasma Na+ level. However, transient decrease in the plasma K+ level was observed; decrease in K+ level two weeks after gossypol treatment was restored to normal after 4 weeks of gossypol treatment. No changes in the histology of the testis were observed 2 weeks after gossypol treatment but marked inhibition of spermatogenesis was observed 4 weeks after gossypol treatment. Motility of vas deferens spermatozoa was also markedly inhibited 4 weeks after gossypol treatment. In the light of the present observations and those of others, there is a clear demonstration that gossypol acts directly on the spermatozoa and on the testis; at both the sites the drug interferes in the ATPase activity.

Adenosine Triphosphatases↗

PubMedDate not supplied

Studies on the male antifertility agent--gossypol acetic acid. V. Effect of gossypol acetic acid on the fertility of male rats.

Gossypol acetic acid was given to male rats at a dose of 7.5 mg/rat/day six days a week for ten weeks. After nine weeks of gossypol treatment no implantation sites were observed in the females mated with gossypol treated males. After ten weeks of gossypol treatment all the spermatozoa in the vas deferens were non-motile. Gossypol treatment did not affect the body weight and the weights of the accessory sex organs. Plasma LH and FSH levels, hCG binding in testis and succinic dehydrogenase (SDH) and adenosine triphosphatase (ATPase) activities in liver, kidney and testis were not affected by gossypol treatment. Histological observations of the testis revealed partial damage to the seminiferous tubules. Single high doses of gossypol did not induce significant changes in the body weight and weights of testis and accessory sex organs. ATPase activity in the testis was reduced significantly after gossypol treatment, the enzyme activity in liver and kidney, was however, affected at high doses only. Gossypol treatment had no effect on the histoarchitecture of the testis. Intratesticular administration of gossypol evoked localized damage in the testis. Gossypol treatment had no effect on I125 FSH binding to the rat testis homogenate in vitro.

Animals↗

PubMed2003

Type of cottonseed and level of gossypol in diets of lactating dairy cows: plasma gossypol, health, and reproductive performance.

Objectives were to determine effects of altering gossypol intake by feeding whole linted Upland (WUP) or a 1:2 blend of WUP and cracked Pima (BUPCP) cottonseed on plasma gossypol (PG) concentrations, reproduction, and health of Holstein cows. Cows, 813, on three dairy farms were assigned to one of two diets starting at 13 +/- 11 d in milk for a 170-d experiment. Diets contained 717 and 951 mg of free gossypol/kg of dry matter from WUP and BUPCP, respectively. Concentrations of PG, as well as the proportion of total gossypol (TG) as the minus isomer were higher for cows fed BUPCP vs cows fed WUP. Conception rate at the first postpartum artificial insemination did not differ between treatments. However, cows consuming the higher gossypol diet had reduced subsequent conception rates and a lower pregnancy rate. Incidence of abortions increased in the higher gossypol diet, and cows that aborted or remained open had higher PG concentrations. Increasing PG concentrations resulted in reduced conception rates and extended days open. The probability of conception after the first artificial insemination declined at a decreasing rate as the plasma TG increased. Incidence of health disorders were unaffected by gossypol intake and PG concentrations. Similarly, gossypol intake and PG concentrations had no effect on culling or mortality. Six cows died in each diet, and none had postmortem signs compatible with gossypol toxicity. Consumption of a high gossypol diet for 170 d had no effect on health of lactating dairy cows, but it increased PG concentrations and impaired reproductive performance.

Abortion, Veterinary↗

PubMed2000

Gossypol blood levels and inhibition of spermatogenesis in men taking gossypol as a contraceptive. A multicenter, international, dose-finding study.

The safety and efficacy of gossypol continues to be controversial. The aim of this study was to evaluate gossypol as a contraceptive pill for men at doses lower than those previously prescribed and in men from various ethnic origin. A total of 151 men from Brazil, Nigeria, Kenya, and China were divided into two groups. Both groups received 15 mg gossypol/day for 12 or 16 weeks to reach spermatogenesis suppression. Subjects were then randomized to either 7.5 or 10 mg/day for 40 weeks. In addition, 51 men were enrolled as a control group. In all, 81 subjects attained spermatogenesis suppression. Only one man discontinued treatment because of tiredness. Potassium levels fluctuated within the normal range. FSH increased consistently. Testicular volume decreased, but after discontinuation, values returned to levels not statistically different from admission. Of 19 subjects on the 7.5 mg/day dose group, 12 recovered sperm counts >20 million/mL within 12 months of discontinuing gossypol. In the 10 mg/day group, sperm counts recovered in only 10 of 24 subjects. Eight of the 43 patients remained azoospermic 1 year after stopping gossypol. All men diagnosed with varicocele failed to reverse spermatogenesis suppression. Gossypol blood levels indicated that sperm suppression occurs independently of concentration, whereas spermatogenesis recovery appears to be concentration-dependent. Gossypol may become a medical alternative to surgical vasectomy when the delay in onset of infertility is acceptable. When taken for 1 year, gossypol causes no reduction in sexual desire or frequency of intercourse. The possibility of reversal, occurring in 51% of the men on this regimen within 1 year after stopping gossypol, is an advantage of this compound as compared with surgical sterilization in many parts of the world.

Adult↗

PubMed2006

Isolation of 6-methoxy gossypol and 6,6'-dimethoxy gossypol from Gossypium barbadense Sea Island cotton.

6-methoxy gossypol and 6,6'-dimethoxy gossypol were isolated from the seeds and root bark of a St. Vincent Sea Island variety of cotton (AZK-267, GRIN# PI 528406). Crude mixtures of gossypol and the methoxy compounds were obtained by extraction of the tissue with acetone and precipitation with acetic acid. After recrystallization, the preparations were treated with 3-amino-1-propanol to form gossypol Schiff's bases, which were separated by preparative reverse phase chromatography. The separated Schiff's bases were then hydrolyzed with acid, extracted into diethyl ether, concentrated, and precipitated with acetic acid. From the above procedure, both methoxy gossypol compounds were obtained as 1:1 molar acetic acid solvates. Each compound was prepared in sufficient amounts to determine its physical properties and begin testing for bioactivity. Light absorbance differed significantly for the di-3-amino-1-propanol derivatives of gossypol and the methoxy gossypol compounds at 254 nm. Relative response factors were developed, which can be used for determining or correcting analytical measurements of these methylated gossypol forms.

Acetic Acid↗

PubMed1988

The effects of gossypol on nuclear protein in rat testes. II. The synthesis of histones and testis-specific proteins after gossypol treatment.

This communication is to report the effects of gossypol on the synthesis of chromosomal basic proteins in the spermiogenic cells. A double-labelling experiment has been performed. The control rats received 14C-arginine, whereas the gossypol-treated rats received a 3H-arginine injection. An equal volume of the tissues (from control and gossypol-treated) were combined, and the total nuclear basic proteins (TNBP) from round spermatids (RS) and elongating spermatids (ES) were extracted for electrophoretic separation. By studying the ratio of 3H/14C, it was indicated that the synthesis of H1, H3, H2B plus H2A and TP1 in the RS was reduced by gossypol. The amount of inhibition of these proteins were 48%, 19%, 27%, and 11%, respectively. In the ES, the synthesis of H1, H3, H2B plus H2A, H4 plus TP2, TP3, and TP1 was reduced by gossypol, the reduction was 33%, 22%, 26%, 14%, 33%, and 8%, respectively. The synthesis of S1 protein was not inhibited by gossypol in both RS and ES.

Administration, Oral↗

PubMed1986

Studies on structure-activity relationship of gossypol, gossypol ethers and three naphthaldehydes in the inhibition of spermatozoal metabolism.

Gossypol tetramethyl ether [C30 H24 O2(OCH3)4] and gossypol hexamethyl ether [C30 H24 O2(OCH3)6], which in contrast to gossypol are stable compounds, were tested for their ability to depress fructose degradation in fresh human sperm cells. Both ethers inhibited spermatozoal fructolysis, yet less effectively than did the parent compound. A synthetic compound, O-hydroxylnaphthaldehyde, and two commercially available preparations, 1- and 2-naphthaldehydes, were also tested under the same experimental conditions. These preparations represent about half of the gossypol molecule and possess a reactive aldehyde group in their molecules. Their inhibitory effect on fructose degradation in fresh human sperm cells, however, was considerably smaller than that of gossypol itself. It thus appears that the whole ring structure of gossypol rather than the intact aldehyde group is required for an effective inhibition of spermatozoal energy metabolism.

Aldehydes↗

PubMed2000

[A beam of dawn light of study on gossypol as a safe, effective, and reversible male antifertility contraceptive--evaluation of the studies by using low dose gossypol combined with steroid hormone for male contraception].

The present paper is an evaluation of the studies of two articles published in this issue of the journal which adopted a new regimen of low dose gossypol(12 mg.kg-1.d-1) combined with steroid hormones (methyltestosterone 20 mg.kg-1.d-1 and ethinyl estradiol 100 micrograms.kg-1.d-1) for 6 weeks as initial dose, and a similar low dose gossypol alone for 12 weeks as maintenance dose. Results showed that the dosage regimen could damage the epididymal sperms and onset of antifertility within 6 weeks in male rats, and prevent the incidence of the side effect of irreversible azoospermia. There was no adverse effect in viscera tissues, and the infertility could be reversible in about 6 weeks following withdrawal of gossypol. Male volunteers taking low dose gossypol (15 mg/d) could induce antifertility within 12 weeks, then followed by a maintenance dose of gossypol(10 mg/d) for 44 weeks. All of them remained infertile, and without developing hypokalemia and irreversible azoospermia. The fertility and the inducing abnormal histone-to-protamine replacement reaction as well as alteration of nuclear basic proteins could be recovered 10 weeks after withdrawal of drug treatment. These results provide a new approach for using the new regimen in clinical trial and a new prospect of gossypol as a potential male contraceptive.

Animals↗

PubMed2005

Effects of source of gossypol and supplemental iron on plasma gossypol in Holstein steers.

Four experiments were conducted to evaluate factors influencing concentrations of plasma total gossypol (TG) in 30 Holstein steers fed cottonseed products. At the end of each 28-d experiment, steers were weighed and blood samples were collected and analyzed for plasma TG concentrations. During the entire study, steers did not show any overt signs of gossypol toxicity. In the 28 d before experiment 1, 30 steers with a body weight (BW) of 273 kg were fed a standardization diet with 15.0% Upland whole cottonseed (WCS) that resulted in a mean intake of 9.08 g/d of TG per steer/d and a plasma TG of 1.66 microg/mL. In experiment 1, 30 steers were fed 1 of 5 diets with 15.0% Upland WCS, but different levels of supplemental Fe [0, 150, 300, 450, and 600 mg/kg of diet dry matter (DM)]. Average daily gain was not affected by level of Fe in the diet, but DM intake, plasma TG, and plasma TG response decreased linearly as Fe in diets increased. In experiment 2, steers were fed diets with 15.0% Upland cottonseed as whole, cracked, roasted, cracked-roasted, or extruded. Analysis of the seed revealed that roasting or extrusion markedly reduced free gossypol (FG) content. Minor effects on animal performance were observed, but plasma TG decreased with roasting or extrusion of seeds, with the greatest reduction when the seed was cracked and then roasted. In experiment 3, steers were fed 2 levels of WCS (7.0 or 14.0% of DM) with 3 levels of cottonseed meal (2.8, 5.5, or 8.5% of DM) in the diet. Animal performance was not altered by diet, but plasma gossypol concentrations and responses were greater in steers fed diets with more WCS, because of the greater FG intake. In experiment 4, 24 steers were fed diets with 15.0% cottonseed (Upland or Pima) either as whole or cracked. Pima cottonseed increased TG and FG intakes, which resulted in greater plasma TG concentration and response. Animal response to processing of cottonseed tended to differ according to type of cottonseed. However, feeding Pima and cracking of cottonseed increased gossypol availability and plasma TG concentrations.

Animals↗

PubMedDate not supplied

The correlation between the gossypol contents in blood plasma, rete testis fluid, and cauda epididymal fluid following chronic treatment with gossypol in rats.

Concentrations of gossypol in blood plasma, rete testis fluid, and fluid from the caudia epididymidis were measured simultaneously by high performance liquid chromatography in rats treated with gossypol (15 mg/kg daily for 3 weeks). Antispermatogenic effects were demonstrated by loss of sperm motility in the cauda epididymidis and structural changes in the testis. It was found in these treated rats that concentrations of gossypol were lower in rete testis fluid compared with blood plasma but increased significantly in fluid from the cauda epididymidis. The results indicate a restriction of the blood-testis barrier to gossypol and its local concentration in the epididymis after fluid resorption.

Animals↗

PubMed1988

The toxicology of gossypol acetic acid and (-)-gossypol.

The toxicity of gossypol has been investigated in Sprague-Dawley rats at dosages of 0, 0.5, 5.0 and 25 mg/kg per day of (+/-)-gossypol acetic acid. The most significant toxicological finding was marked suppression of body weight gain in rats receiving 25 mg/kg per day. Terminal studies showed 6 out of 20 rats receiving 25 mg/kg per day to have varying degrees of testicular pathology. Five mg/kg per day was shown to be a "no effect" level. A study in cynomolgus monkeys at 25 mg/kg per day of (+/-)-gossypol acetic acid for 13 weeks induced death, a variety of clinical signs, extensive biochemical change and pathology in the heart, liver, kidney and testes. The toxicity of (-)-gossypol was investigated in male cynomolgus monkeys at dosages of 1.5, 4 or 5 mg/kg/day for 4 weeks. No animals died. Clinical signs involving the gastrointestinal tract, adverse effects on body weight gain, consistent biochemical changes in serum proteins, calcium, inorganic phosphorus and serum cholesterol were recorded at 4 mg/kg per day and above. Morphological change was not induced.

Animals↗

PubMedDate not supplied

Studies on the male antifertility agent-gossypol acetic acid. II. Effect of gossypol acetic acid on the motility and ATPase activity of human spermatozoa.

A marked reduction in the motility of the human spermatozoa was observed when spermatozoa were incubated with 10 and 100 microgram of gossypol acetic acid for different time period at 37 degrees C; the motility was reduced from 83% to 4% after 210 minutes (P less than 0.001). A significant decrease in the activities of Ca++ and Mg++ activated ATPase in the spermatozoa was observed after gossypol treatment (P less than 0.005). Changes in the zinc++ concentration in the spermatozoa after gossypol treatment were, however, not significant. The present investigations suggest that inhibition of the sperm motility after gossypol treatment may be due to the inhibition of the ATPase activity in the spermatozoa.

Adenosine Triphosphatases↗

PubMedDate not supplied

Studies on the male antifertility agent gossypol acetic acid. VI. Effect of gossypol acetic acid on the fertility of bonnet monkey. Macaca radiata.

Gossypol acetic acid (4 mg/day/5 days a week) suspended in Tonoferon tonic was given to male bonnet monkeys, Macaca radiata, by oral route for 3 months. Marked reduction in the sperm count/ejaculate and sperm motility were observed after gossypol treatment; both motility and sperm count/ejaculate returned to the normal level 8-10 weeks after termination of gossypol treatment. The citric acid and fructose levels in the semen of gossypol treated monkeys were not different from those of the controls.

Animals↗

PubMed2002

Type of cottonseed and level of gossypol in diets of lactating dairy cows: effects on lactation performance and plasma gossypol.

Objectives were to determine the effects of feeding whole linted Upland (WUP) and cracked Pima cottonseed (BUPCP) to lactating cows on plasma gossypol concentrations and lactation performance. Holstein cows (n = 813) from three commercial dairies were assigned to one of two diets starting at 13+/-11 d in milk (DIM) for a 170-d experimental period. Cottonseed was included at 10% of the diet dry matter, and treatments consisted of replacing WUP with a 1:2 blend of BUPCP. Blood was collected from all cows at 61 and 91 DIM and from a subset of 56 cows on one dairy at 10, 33, 61, 91, 120, and 152 DIM. Intakes of free gossypol increased 32% in cows receiving the BUPCP diet, and concentrations of total gossypol (TG), as well as the proportion of TG as minus (-) isomer in plasma, were higher for cows fed BUPCP than WUP. Plasma TG increased linearly with increasing DIM, but cows fed the BUPCP, especially multiparous cows, had a higher increase in plasma TG over time. Yields of milk and milk components did not differ between the two treatments, although, yields of milk and milk components were greater in cows with higher plasma TG. Replacement of WUP cottonseed with BUPCP cottonseed increased plasma gossypol, but dry matter intake and yields of milk and milk components were not affected.

Animal Feed↗

PubMed1990

[Studies on the resolution of racemic gossypol. III. Study on the chemical and physical properties of the amino condensates of gossypol].

Fifteen condensates of chiral amines and racemic gossypol were prepared. Their 1HNMR spectra indicated that all the amine condensates tested had the same keto-enamine structures and shifts of protons on C11, C11 of various condensates were analyzed for their structural relationship. The Rf and delta Rf values (difference between (+) and (-)gossypol condensates) on TLC of these derivatives and stability of eight condensates of (-)gossypol were examined. All these properties were discussed in light of the configuration of gossypol. These studies not only provided rational basis of selecting resolving agent, but also gave indications of their relative absorbability and stereochemistry of the condensates which might be useful in postulating their in vivo behaviors and designing derivatives with better pharmacological actions.

Gossypol↗

PubMed2006

1H- and 13C-NMR, FTIR, UV-VIS, ESI-MS, and PM5 studies as well as emission properties of a new Schiff base of gossypol with 5-methoxytryptamine and a new hydrazone of gossypol with dansylhydrazine.

A new Schiff base of gossypol with 5-methoxytryptamine (GSTR) and a new hydrazone of gossypol with dansylhydrazine (GHDH) have been synthesized and studied by Fourier transform infrared (FTIR), 1H and 13C nuclear magnetic resonance (NMR), ultraviolet-visible (UV-VIS), electrospray ionization-mass spectroscopy (ESI-MS) as well as the parametric method PM5. The spectroscopic methods have provided clear evidence that GSTR exists in chloroform solution as an enamine-enamine tautomer, whereas GHDH is present in chloroform as a N-imine-N-imine tautomer. The fluorescence spectra of both compounds indicate that their quantum yield of fluorescence is increased by one or two orders of magnitude compared to that of pure gossypol. The ESI-MS spectra of the 1:1 mixtures of GSTR or GHDH with formic acid have demonstrated that both compounds exist as protonated monomers in the gas phase, whereas GHDH can also exist in a stable protonated dimeric structure. The structures of the stable tautomers are calculated and visualized using the PM5 semiempirical method. The intra- and intermolecular hydrogen bonds within these structures are discussed.

5-Methoxytryptamine↗