Studies on the male antifertility agent gossypol acetic acid. VII. Effect of motility stimulated factors on the revival of human spermatozoal motility after gossypol treatment in vitro

Silica Gel Chromatographic Methods for Identification, Isolation and Purification of Gossypol Acetic Acid

Several cottonseed varieties are cultivated in different countries. Each variety produces a different amount of gossypol as a natural toxic compound. The rising interest in cottonseed products (oil and feed) increases the demand for establishing simple methods for gossypol detection. Silica gel-based methods are ideal for its isolation, purification, and characterization. Silica gel-based methods are variants and can be used as simple methods for tracking plants' compounds. In this study, gossypol was isolated, characterized, and purified as gossypol acetic acid in the form of yellow crystals. Methods used for its characterization were TLC, preparative TLC, silica gel column, UV/IR spectrophotometer, and HPLC (robust spherical silica gel). A comparative study between its amount in both the Egyptian and Chinese varieties was performed. Under the experimental conditions, the Egyptian's cottonseed contains 8.705 gm/kg, while the Chinese's cottonseed contains 5.395 gm/kg. The TLC used in this study proved to be fast, accurate, and inexpensive. It can be used for gossypol acetic acid evaluation and quantification. Additionally, using TLC as a pre-purification step will give a pre-judgment for the sample's purity and quality. This step will protect the expensive HPLC silica gel-based column from any unexpected impurities. During each step, the silica gel itself could be simply removed by paper filtration. Collectively, the different silica gel-based methods as well as the other used methods are recommended for better Gossypol acetic acid isolation, purification, and characterization, as well as for maintaining HPLC columns.

The potential roles of gossypol as anticancer agent: advances and future directions

Gossypol, a polyphenolic aldehyde derived from cottonseed plants, has seen a transformation in its pharmaceutical application from a male contraceptive to a candidate for cancer therapy. This shift is supported by its recognized antitumor properties, which have prompted its investigation in the treatment of various cancers and related inflammatory conditions. This review synthesizes the current understanding of gossypol as an anticancer agent, focusing on its pharmacological mechanisms, strategies to enhance its clinical efficacy, and the status of ongoing clinical evaluations.The methodological approach to this review involved a systematic search across several scientific databases including the National Center for Biotechnology Information (NCBI), PubMed/MedLine, Google Scholar, Scopus, and TRIP. Studies were meticulously chosen to cover various aspects of gossypol, from its chemical structure and natural sources to its pharmacokinetics and confirmed anticancer efficacy. Specific MeSH terms and keywords related to gossypol's antineoplastic applications guided the search strategy.Results from selected pharmacological studies indicate that gossypol inhibits the Bcl-2 family of anti-apoptotic proteins, promoting apoptosis in tumor cells. Clinical trials, particularly phase I and II, reveal gossypol's promise as an anticancer agent, demonstrating efficacy and manageable toxicity profiles. The review identifies the development of gossypol derivatives and novel carriers as avenues to enhance therapeutic outcomes and mitigate adverse effects.Conclusively, gossypol represents a promising anticancer agent with considerable therapeutic potential. However, further research is needed to refine gossypol-based therapies, explore combination treatments, and verify their effectiveness across cancer types. The ongoing clinical trials continue to support its potential, suggesting a future where gossypol could play a significant role in cancer treatment protocols.

Structure, properties of gossypol and its derivatives-from physiological activities to drug discovery and drug design

Covering up to 2022Gossypol is a polyphenolic compound isolated from cottonseed. There are two optical enantiomers of gossypol, (-)-gossypol and (+)-gossypol. Gossypol exists as three different tautomers, aldehyde, ketone and lactol. Gossypol is toxic and provides a protective mechanism for cotton plants against pests. Gossypol was used as a male contraceptive in China in the 1970s. It was eventually abandoned due to noticeable side effects, disruption of potassium uptake and incomplete reversibility. Gossypol has gained considerable research interest due to its attractive biological activities, especially antitumor and antivirus. Gossypol derivatives are prepared by a structural modification to reduce toxicity and improve their therapeutic effect. This review depicts the bioactivity and regulation mechanisms of gossypol and its derivatives as drug lead compounds, with emphasis on its antitumor mechanism. The design and synthesis of pharmacologically active derivatives based on the structure of gossypol, such as gossypol Schiff bases, apogossypol, gossypolone, are thoroughly discussed. This review aims to serve as a reference for gossypol-based drug discovery and drug design.

The inhibitory effects of gossypol on human sperm motility characteristics: possible modes of reversibility of those effects

Gossypol (GOS) is a polyphenolic compound derived mainly from cottonseed oil, which has been found to have anti-fertility effects in males. It has been reported to induce disturbances of the hypothalamicpituitary axis, disruption of spermatogenesis in the testes, and inhibition of postejaculatory spermatozoa motility. The inhibition of human sperm motility by GOS has been documented both in vivo and in vitro, although the exact mechanism and possible reversibility of such inhibition is unknown. The objectives of the present study were 1) to examine the in vitro dose response of human sperm motility to GOS, and 2) to determine if the motility inhibition of GOS was reversible, using agents which alter the second messenger cyclic adenosine monophosphate (cAMP), such as, 8-bromo-cAMP (8-Br-cAMP), and forskolin, and adenylate cyclase stimulator. Fresh spermatozoa were obtained from males of known fertility. Motile spermatozoa were recovered via the SpermPrep (SP) method and used further in all experiments. Quantitative and qualitative sperm parameters were recorded at collection, post-SP filtration and post-treatment. Motile spermatozoa were resuspended in either media (SP), or in increasing concentrations of GOS (10, 20, 30 and 50 micrograms/ml) as gossypol acetic acid in media. To study the possible reversibility of the GOS effects, spematozoa already exposed to GOS for 2 hr (at the concentrations mentioned above) were centrifuged and reconstituted in media containing either 10 mM 8-Br-cAMP or 100 microM forskolin and measurements of percent motility and grade of motility (0-4) were taken at 0 time and at 30 min intervals for a total of 2 hr. Each experiment was replicated 8 times. The results obtained in this study showed that GOS inhibited sperm motility in a dose and time dependent manner. The motility characteristics of the 50 micrograms/ml GOS group were lower than all other groups (p < 0.001) and the spermatozoa were completely immobilized within 60 min. Cyclic AMP somewhat rescued the GOS-treated sperm, whereas exposure of GOS-treated sperm to forskolin had no such effects. The data generated in the present study suggest that GOS inhibits cAMP formation, which subsequently decreases sperm motility characteristics. At low concentrations (up to 20 micrograms/ml for 30 min), GOS inhibition is reversibile and compounds that act to increase cAMP seem to be partially responsible for the reversal of GOS inhibition. However, GOS inhibitory effects at levels higher than 20 micrograms/ml (exposed for 30 min) were impossible to reverse, which suggest that GOS at those levels could be an effective agent for vaginal contraception.

The effects of cyclic adenosine monophosphate, forskolin, and theophylline on motility parameters in gossypol-treated human sperm

OBJECTIVE

To examine the effect of gossypol on human sperm in vitro and the mechanism for the effect.

DESIGN

Fresh sperm ejaculates obtained from normal donors to the University of Kentucky Andrology Donor Program were exposed to gossypol. Motility was studied manually and using computer-assisted sperm analysis. In subsequent experiments, the effects of forskolin, theophylline, and cyclic adenosine monophosphate (cAMP) on sperm motion were measured.

SETTING

University of Kentucky Department of Obstetrics and Gynecology Andrology Laboratory.

MAIN OUTCOME MEASURES

Manual and computer-assisted measurements of sperm motility and motion characteristics.

RESULTS

Gossypol inhibited sperm motility, which could be reversed partially by increasing cAMP.

CONCLUSION

Gossypol exposure in vitro adversely affects sperm motility in a dose- and time-dependent manner by a cAMP-dependent mechanism.