Toxicity of Gossypol from Cottonseed Cake to Sheep Ovarian Follicles

Effective gossypol removal from cottonseed meal through optimized solid-state fermentation by Bacillus coagulans

BACKGROUND

Cottonseed meal (CSM) is the main by-product of the cottonseed oil extraction process with high protein content, which is an important protein source for feed industry. However, CSM contains free gossypol (FG), a toxic substance that is detrimental to animal health and greatly limits its application. Microbial fermentation is currently considered to be one of the most effective methods to reduce FG and other anti-nutritional factors in CSM. Previously, yeast and bacteria species are used for degradation of FG in CSM, but showing less detoxification efficiency. Bacillus coagulans combines the properties of both lactic acid bacteria and Bacillus, producing both lactic acid and spores, and is considered a potential probiotic. In this study, we aimed to evaluate and optimize the effect of the solid-state fermentation process using a Bacillus coagulans to gossypol removal contained cottonseed meal.

RESULTS

36 B. coagulans strains were isolated and found to have the ability to remove free gossypol. Through the evaluation of strains and optimization of fermentation conditions including fermentation temperature, ratio of material to water, inoculation amount, fermentation time and pH, we have established a solid-state fermentation process using a Bacillus coagulans strain S17 on CSM substrate with 1:1 of the material-to-water ratio, 15% (v/w) seed inoculation, 2% expanded corn flour, 1% bran, and 0.3%-0.8% metal irons at 40 °C for 52 h. After fermentation, the FG content in CSM was reduced from 923.80 to 167.90 mg/kg with 81.83% detoxification efficiency. Meanwhile, the crude protein content in CSM increased from 47.98 to 52.82%, and importantly, the spore concentration of strain S17 reached 1.68 × 10¹⁰ CFU/g dry material.

CONCLUSION

The study showed that B. coagulans have the potential strong ability to degrade free gossypol through cottonseed meal fermentation. This study presents a feasible process for improving the resource utilization rate and nutritional value of CSM via solid-state fermentation through B. coagulans S17.

High-Gossypol Whole Cottonseed Exhibited Mediocre Rumen Degradability and Less Microbial Fermentation Efficiency than Cottonseed Hull and Cottonseed Meal with an In Vitro Gas Production Technique

To explore whether or not the gossypol varied in cottonseed by-products affect rumen degradability and fermentation efficiency, an in vitro cumulative gas production experiment was applied with mixed rumen microorganism to compare rumen fermentation characteristics of whole cottonseed (WCS, n = 3 samples), cottonseed meal (CSM, n = 3 samples), and cottonseed hull (CSH, n = 2 samples). The five-replicate fermentation per sample per incubation time continuously lasted for 0.5, 1.5, 3, 6, 12, 24, 36, and 48 h with an automated gas production recording system. Regardless of distinct nutrient differences, the free gossypol level in these cottonseed by-products ranked: WCS > CSH > CSM. After 48 h of incubation, the in vitro dry matter degradability and ammonia N concentration ranked as: CSM > WCS > CSH. The cumulative gas production and total volatile fatty acid (VFA) levels in the culture fluids ranked: CSM > CSH > WCS, in which the average production rate ranked: CSM > WCS > CSH. Regarding the molar VFA pattern, WCS in comparison with CSH and CSM presented the lowest production of non-glucogenic acids (e.g., acetate) and exhibited the highest fermentation efficiency of energy from carbohydrates to VFAs. There was a significant negative correlation between the gossypol content and cumulative gas and total VFA production, suggesting that the greater gossypol in cottonseed by-products, the more detrimental effect occurred for rumen fermentation. In a brief, WCS exhibited mediocre rumen degradability and less microbial fermentation efficiency than CSH and CSM, depending on their gossypol levels.

Cottonseed extracts regulate gene expression in human colon cancer cells

Cotton plant provides economically important fiber and cottonseed, but cottonseed contributes 20% of the crop value. Cottonseed value could be increased by providing high value bioactive compounds and polyphenolic extracts aimed at improving nutrition and preventing diseases because plant polyphenol extracts have been used as medicinal remedy for various diseases. The objective of this study was to investigate the effects of cottonseed extracts on cell viability and gene expression in human colon cancer cells. COLO 225 cells were treated with ethanol extracts from glanded and glandless cottonseed followed by MTT and qPCR assays. Cottonseed extracts showed minor effects on cell viability. qPCR assay analyzed 55 mRNAs involved in several pathways including DGAT, GLUT, TTP, IL, gossypol-regulated and TTP-mediated pathways. Using BCL2 mRNA as the internal reference, qPCR analysis showed minor effects of ethanol extracts from glanded seed coat and kernel and glandless seed coat on mRNA levels in the cells. However, glandless seed kernel extract significantly reduced mRNA levels of many genes involved in glucose transport, lipid biosynthesis and inflammation. The inhibitory effects of glandless kernel extract on gene expression may provide a useful opportunity for improving nutrition and healthcare associated with colon cancer. This in turn may provide the potential of increasing cottonseed value by using ethanol extract as a nutrition/health intervention agent.

Gossypol detoxification in the rumen and Helicoverpa armigera larvae: A review

Gossypol, a phenolic compound found in the cotton plant, is widely distributed in cottonseed by-products. Although ruminant animals are believed to be more tolerant of gossypol toxicity than monogastric animals due to rumen microbial fermentation, the actual mechanisms of detoxification remain unclear. In contrast, the metabolic detoxification of gossypol by Helicoverpa armigera (Lepidoptera: Noctuidae) larvae has achieved great advances. The present review discusses the clinical signs of gossypol in ruminant animals, as well as summarizing advances in the study of gossypol detoxification in the rumen. It also examines the regulatory roles of several key enzymes in gossypol detoxification and transformation known in H. armigera. With the rapid development of modern molecular biotechnology and -omics technology strategies, evidence increasingly indicates that research into the biological degradation of gossypol in H. armigera larvae and some microbes, in terms of these key enzymes, could provide scientific insights that would underpin future work on microbial gossypol detoxification in the rumen, with the ultimate aim of further alleviating gossypol toxicity in ruminant animals.

Gossypol exposure induces mitochondrial dysfunction and oxidative stress during mouse oocyte in vitro maturation

Gossypol is a yellow natural polyphenolic compound extracted from the seeds, leaves, stems, and flower buds of the cotton plant. Several studies have shown that exposure to gossypol impacts reproductive health in both humans and animals. However, whether gossypol exposure would influence oocyte quality has not yet been determined. Here, we studied the effects of gossypol on the meiotic maturation of mouse oocytes in vitro. The results revealed that gossypol exposure did not affect germinal vesicle breakdown (GVBD) but significantly reduced polar body extrusion (PBE) rates. Moreover, we observed meiotic spindle organization and chromosome alignment were entirely disturbed after gossypol exposure. Further, gossypol exposure also caused mitochondrial dysfunction and abruptly decreased the levels of cellular ATP, and diminished the mitochondrial membrane potential (MMP). Accordingly, gossypol-induced oxidative stress was confirmed through an increased level of reactive oxygen species (ROS). Early apoptosis incidence also increased as identified by positive Annexin-V signaling. Collectively, the above findings provide evidence that gossypol exposure impaired oocyte meiotic maturation, disturbed spindle structure and chromosome dynamics, disrupted mitochondrial function, induced oxidative stress, and triggered early apoptosis. These findings emphasize gossypol's adverse effects on oocyte maturation and thus on female fertility.

Cottonseed-derived gossypol and ethanol extracts differentially regulate cell viability and VEGF gene expression in mouse macrophages

Vascular endothelial growth factor (VEGF) plays an important role in chronic inflammation associated with several diseases. Many plant extracts have nutritional and healthy benefits by down-regulating VEGF expression, but there was no report on VEGF regulation by cottonseed extracts in any biological system. The objective was to investigate cell viability and VEGF expression regulated by gossypol and ethanol extracts using lipopolysaccharides (LPS) as a control. MTT, qPCR and immunoblotting techniques were used to monitor cell viability, VEGF mRNA and protein levels in mouse RAW264.7 macrophages. Gossypol dramatically reduced macrophage viability but cottonseed extracts and LPS exhibited minor effect on cell viability. VEGFb mRNA levels were approximately 40 fold of VEGFa in the macrophages. Gossypol increased VEGFa and VEGFb mRNA levels up to 27 and 4 fold, respectively, and increased VEGF protein. LPS increased VEGFa mRNA by sixfold but decreased VEGFb mRNA. LPS increased VEGF protein in 2–4 h but decreased in 8–24 h. Glanded seed extracts showed some stimulating effects on VEGF mRNA levels. Glandless seed coat extract showed increased VEGFb mRNA levels but its kernel extract reduced VEGF mRNA levels. This study demonstrated that gossypol and ethanol extracts differentially regulated cell viability and VEGF expression in mouse macrophages.

Gossypol decreased cell viability and down-regulated the expression of a number of genes in human colon cancer cells

Plant polyphenol gossypol has anticancer activities. This may increase cottonseed value by using gossypol as a health intervention agent. It is necessary to understand its molecular mechanisms before human consumption. The aim was to uncover the effects of gossypol on cell viability and gene expression in cancer cells. In this study, human colon cancer cells (COLO 225) were treated with gossypol. MTT assay showed significant inhibitory effect under high concentration and longtime treatment. We analyzed the expression of 55 genes at the mRNA level in the cells; many of them are regulated by gossypol or ZFP36/TTP in cancer cells. BCL2 mRNA was the most stable among the 55 mRNAs analyzed in human colon cancer cells. GAPDH and RPL32 mRNAs were not good qPCR references for the colon cancer cells. Gossypol decreased the mRNA levels of DGAT, GLUT, TTP, IL families and a number of previously reported genes. In particular, gossypol suppressed the expression of genes coding for CLAUDIN1, ELK1, FAS, GAPDH, IL2, IL8 and ZFAND5 mRNAs, but enhanced the expression of the gene coding for GLUT3 mRNA. The results showed that gossypol inhibited cell survival with decreased expression of a number of genes in the colon cancer cells.

Intramolecular Annulation of Gossypol by Laccase to Produce Safe Cottonseed Protein

The presence of the phenol gossypol has severely limited the utilization of cottonseed meal and oil in the food and animal feed industries. Highly efficient means of biodegradation of gossypol and an understanding of the cytotoxicity of its degradation products remain outside current knowledge and are of universal interest. In this work, we showed for the first time that laccase can catalyze the intramolecular annulation of the aldehyde and hydroxyl groups of gossypol for the o-semiquinone radical and originate the released ·OH radical. It was further found that the oxidation of aldehyde groups significantly decreases reproductive toxicity and hepatotoxicity. These results indicate a novel detoxification pathway for gossypol and reveal the crucial role played by radical species in cyclization. This discovery could facilitate the development of safe, convenient, and low-cost industrial methods for the detoxification of cotton protein and oil resources.

Effect of the BH3 Mimetic Polyphenol (-)-Gossypol (AT-101) on the in vitro and in vivo Growth of Malignant Mesothelioma

Malignant mesothelioma (MM) is a primary tumor arising from mesothelial cells. The survival of MM patients following traditional chemotherapy is poor, thus innovative treatments for MM are needed. (-)-gossypol (AT-101) is a BH3 mimetic compound which possesses anti-tumoral activity by targeting multiple signaling transduction pathways. Several clinical trials employing AT-101 have been performed and some of them are still ongoing. Accordingly, we investigated the in vitro effects of AT-101 on cell proliferation, cell cycle regulation, pro-survival signaling pathways, apoptosis and autophagy of human (MM-B1, H-Meso-1, and MM-F1) and mouse (#40a) MM cell lines. In addition, we explored the in vivo anti-tumor activities of AT-101 in a mouse model, in which the transplantation of MM cells induces ascites in the peritoneal space. AT-101 inhibited in vitro MM cells survival in a dose- and time-dependent manner and triggered autophagy, but the process was then blocked and was coincident with apoptosis activation. To confirm the effect of AT-101 in inducing the apoptosis of MM cells, MM cells were simultaneously treated with AT-101 and with the caspase inhibitor, Z-VAD-FMK. Z-VAD-FMK was able to significantly reduce the number of cells in the subG1 phase compared to the treatment with AT-101 alone. This result corroborates the induction of cell death by apoptosis following treatment with AT-101. Indeed, Western blotting results showed that AT-101 increases Bax/Bcl-2 ratio, modulates p53 expression, activates caspase 9 and the cleavage of PARP-1. In addition, the treatment with AT-101 was able to: (a) decrease the ErbB2 protein expression; (b) increase the EGFR protein expression; (c) affect the phosphorylation of ERK1/2, p38 and AKT; (d) stimulate JNK1/2 and c-jun phosphorylation. Our in vivo results showed that the intraperitoneal administration of AT-101 increased the median survival of C57BL/6 mice intraperitoneally transplanted with #40a cells and reduced the risk of developing tumors. Our findings may have important implications for the design of MM therapies by employing AT-101 as an anticancer agent in combination with standard therapies.

Isolation of Cottonseed Extracts That Affect Human Cancer Cell Growth

Cottonseeds are classified as glanded or glandless seeds depending on the presence or absence of gossypol glands. Glanded cottonseed has anticancer property and glandless cottonseed was reported to cause cancer in one animal study. It is important to investigate the effect of bioactive components from cottonseeds. Our objectives were to isolate ethanol extracts from cottonseeds and investigate their effects on human cancer cells. A protocol was developed for isolating bioactive extracts from seed coat and kernel of glanded and glandless cottonseeds. HPLC-MS analyzed the four ethanol extracts but only quercetin was identified in the glandless seed coat extract. Residual gossypol was detected in the glanded and glandless seed kernel extracts and but only in the glanded seed coat extract. Ethanol extracts were used to treat human cancer cells derived from breast and pancreas followed by MTT assay for cell viability. Ethanol extracts from glanded and glandless cottonseed kernels and gossypol significantly decreased breast cancer cell mitochondrial activity. Ethanol extract from glanded cottonseed kernel and gossypol also significantly decreased pancreas cancer cell mitochondrial activity. These results suggest that ethanol extracts from cottonseeds, like gossypol, contain anticancer activities.

Development of an RP-UHPLC-PDA method for quantification of free gossypol in cottonseed cake and fungal-treated cottonseed cake

Cottonseed cake biomass, which is a residue of oil extraction, is potentially appropriate for use as animal feed, given the high mineral, fibre and protein content. The presence of free gossypol, however, a toxic pigment in the glands of the cotton plant, limits use of this biomass for monogastric livestock. A promising method to detoxify cottonseed cake relies on fermentation by fungi, which can eliminate up to 100% of gossypol. In order to quantify trace levels of free gossypol in different cotton materials, including cottonseed cake treated with macrofungi, a simple and rapid chromatographic detection method was developed and validated. Under optimized conditions, extraction was performed using 70% acetone. The extract was then analysed by Ultra High-Performance Liquid Chromatography (UHPLC), with gradient elution on a C18 reverse phase column KINETEX^® (100 x 2.10 mm, 2.6 μm). Methanol-0.1% TFA aqueous solution was employed as mobile phase and PDA detection conducted at 254 nm. The optimized method was validated by analysis of specificity, linearity and range, limit of detection, limit of quantification, precision and accuracy. Detection and quantification limits were observed at 0.2 and 0.5 μg/mL, respectively. With good reproducibility, with precision (RSD)<10% and recovery greater than 94%, the developed assay was appropriate for quantification of low quantities of free gossypol. The validated method was successfully applied to determine trace levels of free gossypol cottonseed treated with a macrofungus.

In vitro study of gossypol's ovarian toxicity to rodents and goats

Gossypol interferes with reproduction, causing damage to sperm, disrupting the estrous cycle and resulting in embryonic lethality. In females, gossypol administration promotes degeneration of ovarian follicles, but it is unknown whether this effect is direct or indirect. Thus, the aim of this study is to determine whether gossypol interferes with folliculogenesis in vitro in rats, mice and goats. Ovaries from rats and mice and fragments of goat ovaries were grown in cell culture for 24 h or 7 days. Four groups were tested: 0 (control), 5, 10 and 20 μg gossypol/ml. After incubation, the ovaries were fixed and processed for histological analysis. Follicles were classified according to their stage of development as either viable or atretic. It was found that the ovaries of rats, mice and goats cultured with gossypol showed an increase in the proportion of atretic follicles and a consequent reduction in the proportion of viable follicles at all stages of follicular development. Compared to the control group, the viability of all ovarian follicles in the rat, mouse and goat groups was reduced after cultivation for 24 h by 56.9%, 56.5% and 68.0%, respectively, with the highest concentration of gossypol (20 μg/mL), and after seven days, the respective reductions were 65.4%, 65.3% and 88.2%. Thus, it is possible that gossypol may directly affect follicular maturation, and consequently female fertility.

Effects of gossypol from cottonseed cake on the blood profile in sheep

Cottonseed cake contains gossypol, a potentially toxic compound that, when consumed by sheep, can affect reproduction, the immune system, and the liver. Changes in hematologic and serum biochemical parameters were monitored for 63 days in 12 Santa Inês ewes, six of which received ration containing 400 g kg(-1) of cottonseed cake. Blood samples were collected at the start of the experiment and weekly thereafter for hematologic assessment and determination of serum urea, creatinine, total protein, and albumin concentrations and for measurement of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and γ-glutamyl transferase activities. No clinical signs of toxicity were observed. Evaluation of the erythron showed that sheep consuming cottonseed cake had an increased packed cell volume (p < 0.05) and increased erythrocyte counts and hemoglobin concentrations (p < 0.05) in the leukogram and serum biochemistry panel. In conclusion, consumption of 400 g kg(-1) cottonseed cake by sheep for 63 days may induce changes in the erythron but no consistent changes in serum biochemical parameters, indicating no damage to the liver or kidneys.