Differential effects of the (+)- and (-)-gossypol enantiomers upon Entamoeba histolytica axenic cultures

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.

Gossypol acetate: A natural polyphenol derivative with antimicrobial activities against the essential cell division protein FtsZ

Antimicrobial resistance has attracted worldwide attention and remains an urgent issue to resolve. Discovery of novel compounds is regarded as one way to circumvent the development of resistance and increase the available treatment options. Gossypol is a natural polyphenolic aldehyde, and it has attracted increasing attention as a possible antibacterial drug. In this paper, we studied the antimicrobial properties (minimum inhibitory concentrations) of gossypol acetate against both Gram-positive and Gram-negative bacteria strains and dig up targets of gossypol acetate using in vitro assays, including studying its effects on functions (GTPase activity and polymerization) of Filamenting temperature sensitive mutant Z (FtsZ) and its interactions with FtsZ using isothermal titration calorimetry (ITC), and in vivo assays, including visualization of cell morphologies and proteins localizations using a microscope. Lastly, Bacterial membrane permeability changes were studied, and the cytotoxicity of gossypol acetate was determined. We also estimated the interactions of gossypol acetate with the promising target. We found that gossypol acetate can inhibit the growth of Gram-positive bacteria such as the model organism Bacillus subtilis and the pathogen Staphylococcus aureus [both methicillin-sensitive (MSSA) and methicillin-resistant (MRSA)]. In addition, gossypol acetate can also inhibit the growth of Gram-negative bacteria when the outer membrane is permeabilized by Polymyxin B nonapeptide (PMBN). Using a cell biological approach, we show that gossypol acetate affects cell division in bacteria by interfering with the assembly of the cell division FtsZ ring. Biochemical analysis shows that the GTPase activity of FtsZ was inhibited and polymerization of FtsZ was enhanced in vitro, consistent with the block to cell division in the bacteria tested. The binding mode of gossypol acetate in FtsZ was modeled using molecular docking and provides an understanding of the compound mode of action. The results point to gossypol (S2303) as a promising antimicrobial compound that inhibits cell division by affecting FtsZ polymerization and has potential to be developed into an effective antimicrobial drug by chemical modification to minimize its cytotoxic effects in eukaryotic cells that were identified in this work.

Hybrid isoquinolines from Thalictrum foetidum: a new type of aporphine inhibiting Staphylococcus aureus by combined mechanisms

Thalfoetines A–D (1–4), unique hybrid aporphine alkaloids with a C-7 aromatic unit formed by a new C–C bond linking two building blocks, were isolated from Thalictrum foetidum.

Tautomerism and stereodynamics in Schiff bases from gossypol and hemigossypol with N-aminoheterocycles

Gossypol, a natural male contraceptive, can be functionalized via dynamic imine linkages, whose tautomerism has been explored in detail.

Yeast Chemogenomic Profiling Reveals Iron Chelation To Be the Principle Cell Inhibitory Mode of Action of Gossypol

Gossypol is an inhibitor of eukaryotic cells with an undetermined mode of action. Here we show that the chemogenomic profile of gossypol is strikingly similar to that of the iron chelators deferasirox and desferricoprogen. Iron import channels Fet1 and Fet3 are prominent in all three profiles. Furthermore, yeast inhibited by gossypol and deferasirox is rescued by the addition of Fe²⁺. We propose that Fe²⁺ chelation is in fact the principle mode of action of gossypol.

Recent applications of the hetero Diels–Alder reaction in the total synthesis of natural products

The synthetic utility and potential power of the Diels–Alder (D–A) reaction in organic chemistry is evident.

Therapeutic potential of gossypol: an overview

CONTEXT

Polyphenols are naturally occurring compounds found in fruits, vegetables, cereals, and beverages. Polyphenols occupy a unique place in biological science for their pharmacological properties. Gossypol is a polyphenolic compound that has attracted attention because of its biological effects.

OBJECTIVE

Gossypol is reported to exhibit antifertility, antioxidant, anticancer, antivirus, antiparasitic, and antimicrobial properties and lower plasma cholesterol. These are summarized with attention to the mechanisms of activity.

METHODS

This review summarizes the results of studies obtained in a comprehensive search of ScienceDirect, PubMed, Scirus, and Web of Science.

RESULTS AND CONCLUSION

The results of these studies provide a comprehensive understanding of the biological action of gossypol and its potential for the prevention of and therapy for resistant tumors and chronic human diseases such as HIV, malaria, and psoriasis.

A divergent strategy for the synthesis of secologanin derived natural products

The syntheses of D,L-geissoschizol, D,L-corynantheidol, D,L-dihydrocorynantheol, D,L-protoemetinol, and D,L-3-epi-protoemetinol have been accomplished from a single synthetic intermediate.

Gossypol--a polyphenolic compound from cotton plant

Gossypol (C(30)H(30)O(8)) is a polyphenolic compound derived from the cotton plant (genus Gossypium, family Malvaceae). The presence of six phenolic hydroxyl groups and two aldehydic groups makes gossypol chemically reactive. Gossypol can undergo Schiff base formation, ozonolysis, oxidation, and methylation to form gossypol derivatives. Gossypol and its derivatives have been the target of much research due to their multifaceted biological activities including antifertility, antivirus, anticancer, antioxidant, antitrypanosomal, antimicrobial, and antimalarial activities. Because of restricted rotation of the internaphthyl bond, gossypol is a chiral compound, which has two atropisomers (i.e., (+)- and (-)-gossypol) that exhibit different levels of biological activities. This chapter covers the physiochemical properties, analyses, biological properties, and agricultural and clinical implications of gossypol.

Effect of racemic and (+)- and (-)-gossypol on the survival and development of Helicoverpa zea larvae

Gossypol is a sesquiterpene that occurs naturally in seed and other parts of the cotton plant. Because of restricted rotation around the binaphthyl bond, it occurs naturally as enantiomeric mixtures with (+)-gossypol to (-)-gossypol ratios that vary between 97:3 and 31:69. Commercial cotton varieties (Gossypium hirsutum) normally exhibit an approximate 3:2 ratio. (+)-Gossypol is significantly less toxic than (-)-gossypol to nonruminant animals; thus, cottonseed containing high levels of (+)-gossypol might be safely fed to nonruminants. Gossypol, however, is an important component in the cotton plant's defense against insect herbivores, but it is not known how cotton plants that exhibit high levels of (+)-gossypol in the foliage might be affected by insect herbivory. To address this question, 1-d-old Helicoverpa zea larvae were fed diets with 0.16, 0.20, and 0.24% racemic, (+)-, and (-)-gossypol. Larval pupal weights, days-to-pupation, and survival were adversely affected by all gossypol diets compared with the control diet. Statistical differences were determined by comparing the compounds among themselves at the three levels and between the three compounds at the same level. When the compounds were compared among themselves, no large differences were observed in pupal weights or in days-to-pupation among any of the diets. Among the three compounds, at the 0.16% level, the diet containing racemic gossypol was the most effective at reducing survival. At the 0.20 and 0.24% levels of racemic (+)- and (-)-gossypol, survival was not statistically different. The overall results indicate that (+)-gossypol is as inhibitory to H. zea larvae as racemic or (-)-gossypol, and thus, cotton plants containing predominantly the (+)-enantiomer in foliage may maintain significant defense against insect herbivory.

Preparation of enantiomeric gossypol by crystallization

Large enantiomorphic crystals of gossypol-acetone (1:3) were grown from acetone solutions of rac-gossypol-acetic acid (1:1) at 4 degrees C. By controlling the initial gossypol concentration, crystallization time, and solution volume, single crystals were grown that weighed >50 mg, equivalent to >37 mg of enantiomeric gossypol. Even larger crystals were possible, but it was difficult to produce these reliably without contamination of the antipode. Essentially all of the acetone within the crystal form was removed by storing the crystals under vacuum for 3-4 days. By employing these techniques, gram quantities of enantiomeric gossypol were prepared in high chemical and optical purity. Based on measured and reported optical rotations, the optical purity of samples prepared by crystallization was greater than the optical purity of samples prepared by chromatographic separation of gossypol-amine diastereomers. The principal limitation of crystallization as a preparative method is the need to determine the chirality and purity of each product crystal. Nevertheless, the method competes favorably with preparative-scale chromatographic procedures.

Spectroscopic studies and PM5 semiempirical calculations of new Schiff bases of gossypol with polyoxaalkylamines

Three Schiff bases of racemic gossypol with polyoxaalkylamines were synthesized and studied by FTIR and (1)H-NMR spectroscopy, and their structures were calculated by the PM5 semiempirical method. These Schiff bases exist in the solid state and in solutions as enamine forms. An increasing length of the polyoxaalkyl chain causes the increase of the interaction of the oxygen atoms of this chain with the OH groups in the 6,6' positions. This interaction is very well evidenced in the FTIR and (1)H-NMR spectra. The structures of the Schiff bases and the hydrogen bonds within these structures are discussed.

Synthesis, characterization and antiamoebic activity of benzimidazole derivatives and their vanadium and molybdenum complexes

Reaction of [MoO(2)(acac)(2)] (where, acac=acetyl acetone) and KVO(3) with 2-(salicylidieneimine) benzimidazole lead to form new complexes [MoO(2)(sal-BMZ)(2)] and K [VO(2)(sal-BMZ)(2)] [where, sal-BMZ=2-(salicylidieneimine) benzimidazole], which showed the monobasic bidentate nature of the ligand in which the phenolic oxygen and the imine nitrogen of the ligand are coordinated to the metal ion. These complexes were characterized along with nine other complexes of oxoperoxovanadium (V), molybdenum (Vl) and tungsten (Vl) with benzimidazole derivatives and screened in vitro by micro dilution technique for their amoebicidal activity with a view to search for a more effective agent against Entamoeba histolytica suggests that compound 2 and 3 might be endowed with important antiamoebic properties since they showed IC(50 )values in a microM range.

A review of plant species assessed in vitro for antiamoebic activity or both antiamoebic and antiplasmodial properties

The resurgence of the protozoal diseases amoebiasis and malaria has been known to occur, from time to time, in endemic and epidemic proportions all over the world. Furthermore, the import of these individual pathogens to other areas from tropical regions encourages these protozoal diseases to occur on a global scale with considerable associated mortality and morbidity. From time immemorial, the cure of these diseases has been attempted with the use of traditional plant products, derived from such species as are available within local habitats and ecosystems, and dependent on their host community for their conservation. Scientific validation and in vitro investigation, continues to be an important requirement for drug development, particularly with the emergence of resistance and cross resistance to some standard drugs used in such protozoal diseases. This paper provides a comparative compilation of the various studies reported between 1982 and 1999, on plants with antiamoebic activities and those which possess both antiamoebic and antiplasmodial activities. The results suggest that it is advisable to increase efforts towards the conservation of such plants, in order to retain their economic and therapeutic significance.

Infection with Trypanosoma brucei potentiates the antifertility effect of gossypol, especially in the protein-malnourished male rat

Reproductive parameters were investigated in gossypol-treated male rats that had been infected experimentally with Trypanosoma brucei and then place on one of two diets of differing (low and normal) protein content. The endpoints assessed were reproductive organ weights, semen epididymal sperm counts, serum testosterone and histological, stereological and histomorphometric evaluation of the testis and accessory reproductive organs. Most of the parameters studied were lowest in the protein-malnourished, gossypol-treated, trypanosome-infected animals, when compared to those obtained from the corresponding animals that were only gossypol-treated or trypanosome-infected. Mean testicular size and the diameter and the total length of seminiferous tubules were especially reduced, indicating that the overall volume of the seminiferous epithelium in these animals was smaller. These findings suggest that reproductive capacity could be impaired in protein-malnourished, trypanosome-infected animals fed on gossypol-containing products, even when there are no obvious clinical signs of disease. This could translate into increased production costs in a farm enterprise. Screening for haemoparasitism would also seem to be worthwhile prior to evaluation and/or use of gossypol (or perhaps other potential contraceptives) in human subjects, especially in communities that are confronted with severe food shortages.