Impairment of human sperm motility and viability by quercetin is independent of lipid peroxidation

Supplementation of sperm cooling medium with Eurycoma longifolia extract enhances native Thai chicken sperm quality and fertility potential

Cooled semen storage methods result in oxidative stress generated by an imbalance between oxidation rates, specifically reactive oxygen species production, and sperm cell antioxidants, leading to degradation of semen quality. We aimed to investigate the impact of adding Eurycoma longifolia (EL) extract as an antioxidant supplement in semen storage medium (IGGKPh semen extender) on semen quality and fertility potential. EL extract at concentrations of 5, 10, 15, and 20 mg/mL was assessed for its antioxidant capacity in IGGKPh semen extender. Our findings revealed that the total phenolic content in the EL extract did not vary significantly across the various concentrations and temperatures tested. However, incubation at 5°C was found to be the most effective temperature for increasing the EL extract antioxidant capacity as assessed via the 2,2-diphenyl-1-picrylhydrazyl inhibition assay in a dose-dependent manner. Supplementation of the IGGKPh semen extender with 15 mg/mL EL extract was found to enhance semen quality during cold storage for up to 48 h (p < 0.05), as evidenced by decreased malondialdehyde levels in cooled semen (p < 0.05). However, antioxidant enzyme activities showed no significant differences among the various experimental groups (p > 0.05). The fertility test showed that the 15 mg/mL EL extract group stored for 24 h had a higher percentage than the control group (p < 0.05). However, there was no significant difference in percentage between the two groups at 48 h of storage (p > 0.05). The hatchability showed no significant difference in both 24 and 48-h storage periods (p > 0.05). Our results indicated that supplementing the IGGKPh semen extender with 15 mg/mL EL extract may positively influence semen quality during storage, suggesting potential applications for enhancing semen quality.

Effect of the addition of 4OHE2 and quercetin in culture media on ROS levels and gene expression in mouse blastocysts

AIMS

The main objective of this work is to elucidate whether Quercetin (Qc) and 4-Hidroxistradiol (4OHE2 ) decrease the level of reactive oxygen species (ROS) in in vitro obtained embryos and to analyse which genes are activated under the treatments that could explain this improvement.

METHODS

Oxidative stress was induced during embryo culture by H2 O2 treatment and ROS production was measured and compared with embryos treated with Qc or 4OHE2 . Gene expression was analysed by Q-PCR in control embryos obtained in utero (IU) or by IVF and compared with the levels found in embryos cultured with Qc or 4OHE2 to determine the effect of these compounds.

KEY RESULTS

Qc strongly reduces ROS levels in embryos after a treatment of 4h. On the contrary, 4OHE2 had no effect in reducing ROS levels in embryos. The addition of these molecules to the culture media upregulate several hypoxia-related genes when Qc is added to the culture media, and implantation-related genes when 4OHE2 is used.

CONCLUSIONS

Qc is a very strong antioxidant molecule that when used for short periods of time during culture can reduce ROS levels and improve embryo quality by activating antioxidant enzymes. 4OHE2 supplementation, despite having no effects in reducing ROS levels, acts directly in the molecular signalling implicated in the implantation process and could be also considered as a supplement for embryo culture during IVF.

IMPLICATIONS

Proper supplementation of the culture media could greatly improve the quality of embryos cultured in vitro , resulting in better results in IVF clinics.

Anti-Inflammatory, Antioxidant, Moisturizing, and Antimelanogenesis Effects of Quercetin 3-O-β-D-Glucuronide in Human Keratinocytes and Melanoma Cells via Activation of NF-κB and AP-1 Pathways

Quercetin 3-O-β-D-glucuronide (Q-3-G), the glucuronide conjugate of quercetin, has been reported as having anti-inflammatory properties in the lipopolysaccharide-stimulated macrophages, as well as anticancer and antioxidant properties. Unlike quercetin, which has been extensively described to possess a wide range of pharmacological activities including skin protective effects, the pharmacological benefits and mechanisms Q-3-G in the skin remained to be elucidated. This study focused on characterizing the skin protective properties, including anti-inflammatory and antioxidant properties, of Q-3-G against UVB-induced or H₂O₂-induced oxidative stress, the hydration effects, and antimelanogenesis activities using human keratinocytes (HaCaT) and melanoma (B16F10) cells. Q-3-G down-regulated the expression of the pro-inflammatory gene and cytokine such as cyclooxygenase-2 (COX-2) and tumor necrosis factor (TNF)-α in H₂O₂ or UVB-irradiated HaCaT cells. We also showed that Q-3-G exhibits an antioxidant effect using free radical scavenging assays, flow cytometry, and an increased expression of nuclear factor erythroid 2- related factor 2 (Nrf2). Q-3-G reduced melanin production in α-melanocyte-stimulating hormone (α-MSH)-induced B16F10 cells. The hydration effects and mechanisms of Q-3-G were examined by evaluating the moisturizing factor-related genes, such as transglutaminase-1 (TGM-1), filaggrin (FLG), and hyaluronic acid synthase (HAS)-1. In addition, Q-3-G increased the phosphorylation of c-Jun, Jun N-terminal kinase (JNK), Mitogen-activated protein kinase (MAPK) kinase 4 (MKK4), and TAK1, involved in the MAPKs/AP-1 pathway, and the phosphorylation of IκBα, IκB kinase (IKK)-α, Akt, and Src, involved in the NF-κB pathway. Taken together, we have demonstrated that Q-3-G exerts anti-inflammatory, antioxidant, moisturizing, and antimelanogenesis properties in human keratinocytes and melanoma cells through NF-κB and AP-1 pathways.

The Role of Selected Natural Biomolecules in Sperm Production and Functionality

Emerging evidence from in vivo as well as in vitro studies indicates that natural biomolecules may play important roles in the prevention or management of a wide array of chronic diseases. Furthermore, the use of natural compounds in the treatment of male sub- or infertility has been proposed as a potential alternative to conventional therapeutic options. As such, we aimed to evaluate the effects of selected natural biomolecules on the sperm production, structural integrity, and functional activity. At the same time, we reviewed their possible beneficial or adverse effects on male reproductive health. Using relevant keywords, a literature search was performed to collect currently available information regarding molecular mechanisms by which selected natural biomolecules exhibit their biological effects in the context of male reproductive dysfunction. Evidence gathered from clinical trials, in vitro experiments and in vivo studies suggest that the selected natural compounds affect key targets related to sperm mitochondrial metabolism and motion behavior, oxidative stress, inflammation, DNA integrity and cell death. The majority of reports emphasize on ameliorative, stimulating and protective effects of natural biomolecules on the sperm function. Nevertheless, possible adverse and toxic behavior of natural compounds has been indicated as well, pointing out to a possible dose-dependent impact of natural biomolecules on the sperm survival and functionality. As such, further research leading to a deeper understanding of the beneficial or adverse roles of natural compounds is necessary before these can be employed for the management of male reproductive dysfunction.

Modulation of Human Sperm Mitochondrial Respiration Efficiency by Plant Polyphenols

Plant bioactives, such as polyphenols, can differentially affect (positively or negatively) sperm quality, depending on their concentration. These molecules have been proposed as natural scavengers of reactive oxygen species (ROS) for male infertility treatment. However, few data are available about their effects on the molecular mechanisms related to sperm quality and, in particular, to sperm mitochondrial function. We investigated the effects of quercetin, naringenin, genistein, apigenin, luteolin, and resveratrol at the concentration of 0.1-1000 nM on mitochondrial respiration efficiency. Upon chemical exposure, spermatozoa were swollen in a hypotonic solution and used for polarographic assays of mitochondrial respiration. All tested compounds, except for apigenin, caused a significant increase in the mitochondrial respiration efficiency at the concentration of 0.1 nM, and a significant decrease starting from concentrations of 10 nM. The analysis of oxygen consumption rate in the active and in the resting state of mitochondrial respiration suggested different mechanisms by which the tested compounds modulate mitochondrial function. Therefore, by virtue of their ability to stimulate the respiration active state, quercetin, genistein, and luteolin were found to improve mitochondrial function in asthenozoospermic samples. Our results are relevant to the debate on the promises and perils of natural antioxidants in nutraceutical supplementation.

Quercetin and Naringenin Provide Functional and Antioxidant Protection to Stored Boar Semen

In this study, we evaluated the impact of 5-50 μM quercetin (QUE) and naringenin (NAR) on extended boar spermatozoa in the BTS (Beltsville Thawing Solution) medium for 72 h. Spermatozoa motion, membrane, acrosome, and DNA integrity were investigated immediately after sample dilution (0 h) as well as after 24 h, 48 h, and 72 h of semen storage. Furthermore, reactive oxygen species (ROS) and superoxide production, as well as the extent of oxidative damage to the sperm proteins and lipids, were assessed to determine the potential of QUE and NAR to prevent a potential loss of sperm vitality due to oxidative stress development. Our results indicate that the most notable parameter influenced by QUE was the mitochondrial activity, which remained significantly higher throughout the experiment (p < 0.001 and p < 0.0001; 10 μM), and which correlated with the most prominent maintenance of sperm motility (p < 0.01, 48 h; p < 0.05, 72 h). A significant membrane stabilization (p < 0.01, 24 h and 48 h; p < 0.0001, 72 h) and prevention of lipid peroxidation (p < 0.05, 24 h and 48 h; p < 0.01, 72 h) was primarily observed following administration of 10 and 25 μM NAR; respectively. Administration of 10 μM QUE led to a significant decrease of superoxide (p < 0.0001, 48 h and 72 h) while the most notable decline of ROS generation was recorded in the case of 10 and 25 μM NAR (p < 0.001). This study may provide new information on the specific mechanisms of action involved in the favorable effects of natural biomolecules on spermatozoa.

Quercetin supplementation to the thawing and incubation media of boar sperm improves post-thaw sperm characteristics and the in vitro production of pig embryos

Elevated levels of reactive oxygen species can cause oxidative stress, which could lead to membrane damage, decreased fertility, and spermatozoan morphological deformities. Antioxidants can be supplemented to reduce the impacts of oxidative stress. The objective of this study was to determine the effects of supplementing quercetin (0.25, 0.50, 0.75 mM) during the thawing and incubation of frozen-thawed boar semen on spermatozoan characteristics, IVF kinetics (n = 400) and subsequent embryonic development (n = 1340). Spermatozoa were evaluated for motility, viability, and membrane lipid peroxidation levels at 0, 2, 4, 6, 8, and 10 h after thawing. Embryos were evaluated for IVF kinetics 12 h after IVF (penetration, polyspermy, male pronucleus formation, IVF efficiency) and cleavage and blastocyst formation at 48 h and 144 h after IVF, respectively. Spermatozoa supplemented with 0.25 mM quercetin had significantly higher (P < 0.05) motility (51.67±8.50 %) and percent of viable cells (61.21 ± 2.44 %) compared to all other treatments at 10 h after thawing, in addition to having significantly (P < 0.05) lower levels of hydroperoxide (3.38 ± 0.88 μM/10⁷cells). There were no differences in penetration rates and male pronucleus formation between treatment groups. Supplementation of quercetin significantly decreased (P < 0.05) polyspermy and significantly increased (P < 0.05) the percentage of embryos reaching blastocyst stage of development by 144 h after IVF compared to no supplementation. Results indicated that supplementing frozen-thawed boar semen with 0.25 mM quercetin improves sperm characteristics up to 10 h after thawing and decreases polyspermy while improving early embryonic development in pigs.

Overview of biological effects of Quercetin on ovary

Over the last few decades, using natural products has been increased to treat different diseases. Today, great attention has been pointed toward the usage of natural products such as flavonoids, especially Quercetin (QUR), in the treatment of diseases. QUR as a natural antioxidant has been traditionally used to prevent or treat a variety of diseases such as cancer, cardiovascular disease, polycystic ovary syndrome (PCOS), obesity, chronic inflammation, and reproductive system dysfunction. Several studies demonstrated that QUR acts as an anti-inflammatory, anti-apoptotic, antioxidant, and anticancer agent. With this in view, in this study, we intended to describe an overview of the biological effects of QUR on the ovary. QUR improves the quality of oocytes and embryos. It affects the proliferation and apoptosis and decreases the oxidative stress in granulosa cells (GCs). Furthermore, QUR can be used as a complementary and alternative therapy in ovarian cancer and it has beneficial effects in the treatment of PCOS patients. It seems that QUR as a supplementary factor has different activities for the treatment of different disorders and it also has bidirectional activities. However, further investigations are needed for understanding the efficacy of QUR in the treatment and improvement of gynecological patients.

Quercetin supplemented casein-based extender improves the post-thaw quality of rooster semen

The advantageous influence of quercetin (Q) supplementation in an extender has not yet been evaluated for rooster semen cryopreservation. This research was purposely conducted in order to assess the effect of different quercetin concentrations added into an extender on the sperm quality of the rooster subsequent to a freezing-thawing process. After the freezing-thawing process, spermatozoa quality parameters (membrane functionality, acrosome integrity, motility, viability, and abnormal morphology), endogenous enzymes (SOD, CAT, and GPx), mitochondrial activity, DNA fragmentation index, lipid peroxidation (MDA), and ROS were all evaluated. A total of 75 neat pooled ejaculates (3 ejaculates/rooster) were collected from 25 arbor acres roosters (24 wks) twice a week using abdominal massage technique, then divided into five equal aliquots and diluted with an extender containing different doses of Q (CS-Q) as follows: casein extender without Q (control only), casein extender containing 0.040 mg/mL quercetin (CS-Q 0.040), 0.020 mg/mL quercetin (CS-Q 0.020), 0.010 mg/mL quercetin (CS-Q 0.010), and 0.005 mg/mL quercetin (CS-Q 0.005). Our results depicted that adding to the extender with a 0.010 mg/mL Q enhanced (P < 0.01) sperm motility, membrane function, viability, mitochondrial activity, intact acrosome (P < 0.05), SOD (P < 0.001), CAT, and GPx (P < 0.01) compared to the control group at post-thaw. Compared to the control group and other treatment groups after the freeze-thawing process, the addition of 0.005 mg/mL Q into the extender also showed higher (P < 0.05) improvement in the quality of sperm parameters and a higher (P < 0.01) SOD and CAT but did not improve mitochondrial activity and sperm viability. In addition, there was a lower degree of DNA fragmentation index, lower (P < 0.05) lipid peroxidation and ROS in frozen-thawed sperm treated with 0.010 mg/mL and 0.005 mg/mL Q than in control and the other treatment groups. In addition, 0.020 mg/mL Q supplementation into the extender also reduced DNA fragmentation and improved GPx activity compared to the control group at post-thaw. Different concentrations of Q 0.010 and 0.005 mg/mL added to the extender reduced the percentage of abnormal spermatozoa compared to the other groups. The results of this study showed for the first time that the inclusion of an extender with a suitable quercetin concentration of 0.010 mg/mL improved the post-thawed quality of rooster semen.

Antimalarial plants with potential male-factor antifertility properties

Malaria, caused mainly by Plasmodium falciparum among other Plasmodium species, is one of the main causes of death from parasitic diseases. Malaria is still a health problem mainly because of the cost of effective antimalarial drugs and the growing parasite resistance to conventional antimalarial drugs, making a great proportion of the people in malaria endemic countries dependent on plants for its treatment. Corollary, a large number of the rural populations consume antimalarial herbal preparations in large or excessive quantities despite the fact that it has been reported that some of them could cause male-factor infertility, a growing global health concern. Few studies have compiled information on the scientifically validated male-factor antifertility effects of these antimalarial plant remedies. The aim of this review therefore is to compile information on commonly used antimalarial plant remedies that have been experimentally validated as having male-factor antifertility effects. Thus, antimalarial plant remedies with experimentally confirmed male-factor antifertility potentials and compounds isolated from them are identified and discussed. The male-factor antifertility effects of these plants include reduction of sperm quality, regulation of reproductive hormone levels and induction of lipid peroxidation. Indiscriminate use of such antimalarial plants is discouraged when male contraception is not desired.

In vitro antioxidation effect of Quercetin on sperm function from the infertile patients with leukocytospermia

PROBLEM

Quercetin has been shown to display intensive antioxidant activity against ROS-mediated damage in chilled semen, and the effects and molecular mechanisms of Quercetin on sperm function in the infertile patients with leukocytospermia remain largely unknown.

METHODS

Semen samples were collected from the infertile men with leukocytospermia (n = 56) and fertile men (n = 44). Computer-assisted semen analysis (CASA) was used to determine sperm motility before and after Quercetin incubation (10 μmol/L). Changes in H₂ O₂ , sperm mitochondrial DNA (mtDNA), cytochrome B (Cty B), and NADH dehydrogenase 5 (NADH5) contents were measured. Furthermore, hyperactivated motility (HA) and acrosome reaction rates were detected after the stimulation by progesterone with or without Quercetin, respectively.

RESULTS

Quercetin could significantly improve sperm motility from the leukocytospermic patients. The level of H₂ O₂ was significantly decreased in the supernatant of leukocytospermic patients after Quercetin treatment. The content of mtDNA in sperm was significantly decreased, whereas the contents of Cyt B and NADH 5 in sperm were significantly increased. Sperm hyperactivated motility and acrosome reaction induced by progesterone were enhanced by Quercetin in sperm from the infertile men with leukocytospermia.

CONCLUSION

These data indicate Quercetin could display protective effects against oxidative damage on sperm from the infertile men with leukocytospermia.

In vivo administration of quercetin ameliorates sperm oxidative stress, inflammation, preserves sperm morphology and functions in streptozotocin-nicotinamide induced adult male diabetic rats

INTRODUCTION

Diabetes mellitus (DM) has been associated with sperm damage. In view of the fact that quercetin possesses antioxidant and anti-inflammatory activities, this compound may help to protect sperm against damage in DM. In this study, in-vivo effects of quercetin on sperm parameters in DM were investigated.

MATERIAL AND METHODS

Quercetin (10, 25 and 50 mg/kg/b.w.) was given orally to streptozotocin-nicotinamide induced adult male diabetic rats for 28 days. Following treatment completion, rats were sacrificed and sperm were harvested from the cauda epididymis. Sperm count, motility, viability, hyperosmotic swelling (HOS) tail-coiled sperm and morphology were assessed. Levels of lipid peroxidation (LPO) and anti-oxidative enzymes (SOD, CAT and GPx) in sperm with and without H₂O₂ incubation were determined by biochemical assays. Expression levels of SOD, CAT and GPx mRNAs in sperm were evaluated by qPCR. Sperm DNA integrity was estimated by flow cytometry while expression levels of the inflammatory markers NF-κβ and TNF-α in sperm were determined by Western blotting.

RESULTS

In diabetic rats receiving quercetin, sperm count and motility, viability and HOS tail-coiled sperm increased (p < 0.05) while sperm with abnormal morphology decreased. Moreover, sperm SOD, CAT, GPx activities and their mRNA expression levels increased while sperm LPO, NF-κβ and TNF-α levels decreased. In normal and diabetic rat sperm incubated with H₂O₂, a further increase in MDA and further decreases in SOD, CAT and GPx were observed, and these were ameliorated by quercetin treatment.

CONCLUSIONS

In-vivo administration of quercetin to diabetic rats helps to ameliorate sperm damage and improves sperm morphology and functions in DM.

Effects of dietary quercetin on female fertility in mice: implication of transglutaminase 2

Use of the dietary supplement quercetin is on the rise. Because previous studies imply an inhibitory effect of quercetin on male fertility, we explored the effects of this flavonoid on fertility in female mice. Birth outcomes, and ovarian morphology in 4-week-old offspring, were assessed in mice receiving dietary quercetin (5mgkg^-1day^-1) for 9 months during two breeding periods: from 2 to 6 months (prime reproductive age) and 8 to11 months of age. Quercetin increased birth spacing, leading to a 60% reduction in the number of litters, but enhanced folliculogenesis in ovaries of female offspring. While in young females quercetin caused an almost 70% increase in litter size, in older animals this effect was reversed. Consistent with the inhibitory activity of quercetin on the enzyme transglutaminase 2 (TG2), genetic ablation of TG2 in mice mirrors the effects of quercetin on birth outcomes and follicular development. Further, TG2-null mice lack responsiveness to quercetin ingestion. Our study shows for the first time that dietary quercetin can cause reduced reproductive potential in female mice and implies that TG2 may regulate ovarian ageing.

Supplementation of quercetin for advanced DNA integrity in bull semen cryopreservation

The aim of this study was to identify the effects of adding quercetin (Q) to Tris extender in order to identify levels of oxidative stress in bull sperm after freeze thawing. Ejaculates were collected via artificial vagina from Holstein bulls. Semen was divided into five tools and diluted to a final concentration of 15 × 106 spermatozoa/ml with the Tris extender containing Q (25, 50, 100 and 200 μg/ml) and no additive (control; C). All examples were equilibrated at 4°C during 4 hr then were loaded into 0.25-ml straws and frozen using a controlled rate. Sperm motility and motility characteristics were determined using the computer-assisted semen analyser. Sperm membrane integrity was assessed using the hypoosmotic swelling test. Sperm chromatin integrity was investigated using the single cell gel electrophoresis. Total antioxidant capacities were performed colorimetrically. Q supplementation used as an antioxidant did not produce better results in the proportion of sperm progressive and total motility, plasma membrane integrity and sperm abnormalities. Q supplementation exhibited the favourable tail length, tail DNA and tail moment. In conclusion, when whole parameters are considered, Q25 can be added to the Tris extender due to its positive effect on sperm DNA integrity and no adverse effect on the progressive and total motilities of sperm.

Beneficial effects of quercetin on titanium dioxide nanoparticles induced spermatogenesis defects in mice

Many recent studies have demonstrated that most nanoparticles (NPs) have an adverse or toxic action on male germ cells. In present study, protective effect of quercetin (Que) on titanium dioxide nanoparticle (NTiO₂)-induced spermatogenesis defects in mice was investigated. Thirty-two Naval Medical Research Institute (NMRI) mice were randomly divided into four groups. Que group received 75 mg/kg of Que for 42 days. NTiO₂ group received 300 mg/kg NTiO₂ for 35 days. NTiO₂ + Que group initially received 75 mg/kg Que for 7 days and was followed by concomitant administration of 300 mg/kg NTiO₂ for 35 days. Control group received only normal saline for 42 days. Sperm parameters, testosterone concentration, histological criteria, and apoptotic index were assessed. Product of lipid peroxidation (MDA), superoxide dismutase (SOD), and catalase (CAT) activities were also evaluated for oxidative stress in testicular tissue. Administration of NTiO₂ significantly induced histological changes in testicular tissue; increased apoptotic index; and decreased testicular weight, testosterone concentration, and sperm quality (p < 0.01). In the testis, NTiO₂ increased oxidative stress through an increase in lipid peroxidation and a decrease in SOD and CAT activities (p < 0.05). Que pretreatment could significantly attenuate testicular weight; apoptotic index; and histological criteria including vacuolization, detachment, and sloughing of germ cells in seminiferous tubules. Serum and tissue testosterone levels were significantly increased in Que-pretreated mice (p < 0.01). Sperm parameters including sperm number, motility, and percentage of abnormality were also effectively improved by Que pretreatment (p < 0.01). Pretreatment of Que significantly ameliorated oxidative stress and increased the activities of SOD and CAT in testicular tissue. These results indicate that sperm production can be increased by Que pretreatment in NTiO₂-intoxicated mice. The improved sperm quality and reverse testis histology by Que pretreatment may be a consequence of elevation testosterone concentration, reduction in germ cell apoptosis, and suppression of oxidative stress in testicular tissue.

Human Sperm Quality and Metal Toxicants: Protective Effects of some Flavonoids on Male Reproductive Function

Background

Metals can cause male infertility through affection of spermatogenesis and sperm quality. Strong evidences confirm that male infertility in metal-exposed humans is mediated via various mechanisms such as production of reactive oxygen species (ROS). Flavonoids have antioxidant and metal chelating properties which make them suitable candidates for neutralizing adverse effects of metals on semen quality. In the current study, we have evaluated the effects of five types of flavonoids (rutin, naringin, kaempferol, quercetin, and catechin) on recovery of sperm motility and prevention of membrane oxidative damage from aluminum chloride (AlCl₃), cadmium chloride (CdCl₂), and lead chloride (PbCl₄).

Materials and Methods

In this experimental study, motility and lipid peroxidation of metalexposed sperm was investigated in the presence of different concentrations of five kinds of flavonoids. Malondialdehyde (MDA) production was assessed as a lipid peroxidation marker.

Results

Aluminum chloride (AlCl₃), cadmium chloride (CdCl₂), and lead chloride (PbCl₄) diminished sperm motility. Treatment of metal-exposed sperm with rutin, naringin, and kaempferol attenuated the negative effects of the metals on sperm motility. Quercetin and catechin decreased the motility of metal-exposed sperm.

Conclusion

Based on the MDA production results, only AlCl₃ significantly induced lipid peroxidation. Treatment with rutin, naringin, and kaempferol significantly decreased MDA production.

Effect of Quercetin-loaded liposomes on induced oxidative stress in human spermatozoa

A strategy to circumvent the poor polyphenols bioavailability is to load these compounds into liposomes. We evaluated the in vitro effects of quercetin (Q) and Q-loaded liposomes (QLL, 30, 50, 100μM) on motility, viability and chromatin integrity of swim-up selected human sperm. Antioxidant power was assayed against tert-butylhydroperoxide induced lipid peroxidation (LPO) using C11-BODIPY581/591 fluorescent probe and transmission electron microscopy. QLL showed decreased toxicity for sperm motility and viability and increased DNA damage compared to Q. The percentage of sperm with fluorescence, marker of LPO, was decreased in samples incubated with Q vs QLL (P<0.001). The ultrastructure of acrosomes and membranes was preserved with Q 30/100μM, whereas QLL did not prevent membrane injury. Q alone appeared more effective than Q incorporated into liposomes; however liposomes could be considered as carriers that may convey different compounds inside sperm; they may therefore represent a field of research rich of many applications.

Alleviative effect of quercetin on rat testis against arsenic: a histological and biochemical study

The preventive effect of quercetin on arsenic stimulated reproductive ailments in male Sprague Dawely (SD) rats was investigated. Twenty rats were divided into four groups. The first group served as a control and was provided tap water. The second group of rats was treated with sodium arsenite at the dose of 50 ppm in drinking water. The third group served as a positive control and received an oral dose of quercetin (50 mg/kg). In the fourth group, quercetin (50 mg/kg) was co-administered orally with arsenic (50 ppm in drinking water). All the treatments were carried out for 49 days. Arsenic treatment resulted in adverse morphological and histopathological changes in testis of rats including reduced epithelial height and tubular diameter, and increased luminal diameter. In contrast, these adverse effects of arsenic were eliminated by co-administration of quercetin. Additionally arsenic treatment significantly increased testicular thiobarbituric acid reactive substance (TBARS) levels while catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and glutathione reductase (GSR) activities, and plasma and intra-testicular testosterone concentrations, were decreased significantly. Lipid peroxidation (LPO) was significantly suppressed and depleted antioxidant defense mechanism was restored by the quercetin co-treatment. Also quercetin treatment resulted in a marked increase in plasma and testicular testosterone concentrations. On the basis of these findings, it was concluded that quercetin may be used as a potential therapeutic drug against arsenic induced reproductive toxicity.

Interaction of PDC-109, the Major Secretory Protein From Bull Seminal Vesicles, With Bovine Sperm Membrane Ca2+-ATPase

PDC-109 is the prevalent secretory protein from bovine seminal vesicles that binds to the midpiece of sperm once they pass the ampulla of the vas deferens during emission. Thereby, the protein changes biophysical membrane properties, eventually resulting in increased sperm motility. To elucidate the underlying biochemical mechanism, we have studied the ion-pumping activity (Ca(2+)-ATPase) in membrane preparations of bovine spermatozoa following in vitro incubation with the protein and analyzed whether PDC-109 influences sperm motility. PDC-109 was purified to homogeneity from bull seminal vesicle extracts using a newly described method. The effect of PDC-109 on sperm motility was analyzed using the CASA-method. These experiments clearly demonstrated that PDC-109 significantly increases sperm motility. Calcium-pumping mechanisms were analyzed by monitoring the effect of PDC-109 on various parameters of enzyme activity of Ca(2+)-ATPase in epididymal sperm plasma membranes and were compared with Ca(2+)-ATPase activities from other organs and from epididymal sperm of different species, respectively. Specificity studies were performed using different Ca(2+)-antagonists. Enzyme activities of both Mg(2+)-dependent and Mg(2+)-independent Ca(2+)-ATPases increased in a dose-dependent manner following the addition of the PDC-109 (range 5-20 microg). Preincubation of PDC-109 at temperatures above 37 degrees C and pHs ranging from below 6.5 and above 8.5 led to the loss of the stimulatory effect. An analysis of enzyme kinetics pointed to irreversible, cooperative interaction of PDC-109 with the enzyme. The effect was organ-specific, that is, restricted to sperm ATPases, but it was not species-specific, as it could be elicited also in rat sperm.

Effect of quercetin, rutin, naringenin and epicatechin on lipid peroxidation induced in human sperm

Quercetin, rutin, naringenin, epicatechin are flavonoids with diverse properties, including antioxidant potential. We evaluated, in vitro, the cytotoxicity of these flavonoids (20, 30, 50, 100, 200, 400 μM) in swim-up selected human sperm. Antioxidant activity was tested against tert-butylhydroperoxide induced lipid peroxidation using a C11-BODIPY(581/591) probe and transmission electron microscopy. A significant concentration-dependent effect on sperm viability (P<0.001) and motility (P<0.001) was observed. Lipid peroxidation was decreased in samples treated with 30 μM quercetin (P<0.01) and 30 μM rutin (P<0.05) versus samples incubated with tert-butylhydroperoxide alone. Naringenin (50-100 μM) showed a low protective effect and epicatechin (200 μM) was not efficacious. Transmission electron microscopy analysis confirmed the protective action of rutin and in particular quercetin on damages induced by lipid peroxidation. These results underlined the antioxidant properties of quercetin and rutin. A possible role of these compounds in the supplementation of media used during semen handling warrants attention and further studies.

Quercetin prevents 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced testicular damage in rats

The protective effect of quercetin on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced testicular damage in rats was investigated. Twenty-two rats were equally divided into four groups; first group was kept as control and given corn oil as carrier. In second group, TCDD was orally administered at the dose of 2 μ (kg week)(-1) for 60 days. In third group, quercetin was orally administered at the dose of 20 mg (kg day)(-1) by gavages, and in fourth group TCDD and quercetin were given together at the same doses. Although TCDD increased the formation of thiobarbituric acid reactive substances (TBARS) significantly, it caused a significant decline in the levels of glutathione (GSH), catalase (CAT), GSH-Px and CuZn-Superoxide Dismutase (CuZn-SOD) in rats. In contrast, quercetin significantly increased the GSH, CAT, GSH-Px and CuZn-SOD levels but decreased the formation of TBARS. In addition, sperm motility, sperm concentration and serum testosterone levels were significantly decreased but abnormal sperm rate and testicular damage were increased with TCDD treatment. However, these effects of TCDD on sperm parameters, histological changes and hormone levels were eliminated by quercetin treatment. Our results show that administration of TCDD induces testicular damage (oxidative stress, testes tissue damage, serum hormone level and sperm parameters), and quercetin prevents TCDD-induced testicular damage in rats. Thus, quercetin may be useful for the prevention and treatment of TCDD-induced testicular damage.

Stimulating effects of quercetin on sperm quality and reproductive organs in adult male rats

AIM

To investigate effects of quercetin on weight and histology of testis and accessory sex organs and on sperm quality in adult male rats.

METHODS

Male Sprague-Dawley rats were injected s.c. with quercetin at the dose of 0, 30, 90, or 270 mg/kg body weight/day (hereafter abbreviated Q0, Q30, Q90 and Q270, respectively), and each dose was administered for treatment durations of 3, 7 and 14 days.

RESULTS

From our study, it was found that the effects of quercetin on reproductive organs and sperm quality depended on the dose and duration of treatment. After Q270 treatment for 14 days, the weights of testes, epididymis and vas deferens were significantly increased, whereas the weights of seminal vesicle and prostate gland were significantly decreased, compared with those of Q0. The histological alteration of those organs was observed after Q270 treatment for 7 days as well as 14 days. The sperm motility, viability and concentration were significantly increased after Q90 and Q270 injections after both of 7 and 14 days. Changes in sperm quality were earlier and greater than those in sex organ histology and weight, respectively.

CONCLUSION

Overall results indicate that quercetin might indirectly affect sperm quality through the stimulation of the sex organs, both at the cellular and organ levels, depending on the dose and the duration of treatment. Therefore, the use of quercetin as an alternative drug for treatment of male infertility should be considered.

A critical review of the data related to the safety of quercetin and lack of evidence of in vivo toxicity, including lack of genotoxic/carcinogenic properties

Quercetin is a naturally-occurring flavonol (a member of the flavonoid family of compounds) that has a long history of consumption as part of the normal human diet. Because a number of biological properties of quercetin may be beneficial to human health, interest in the addition of this flavonol to various traditional food products has been increasing. Prior to the use of quercetin in food applications that would increase intake beyond that from naturally-occurring levels of the flavonol in the typical Western diet, its safety needs to be established or confirmed. This review provides a critical examination of the scientific literature associated with the safety of quercetin. Results of numerous genotoxicity and mutagenicity, short- and long-term animal, and human studies are reviewed in the context of quercetin exposure in vivo. To reconcile results of in vitro studies, which consistently demonstrated quercetin-related mutagenicity to the absence of carcinogenicity in vivo, the mechanisms that lead to the apparent in vitro mutagenicity, and those that ensure absence of quercetin toxicity in vivo are discussed. The weight of the available evidence supports the safety of quercetin for addition to food.

Differential effects of quercetin, a natural polyphenolic flavonoid, on L-type calcium current in pituitary tumor (GH3) cells and neuronal NG108-15 cells

The effects of quercetin, a natural polyphenolic compound, on voltage-dependent L-type Ca(2+) current (I(Ca,L)) in rat pituitary GH(3) cells were investigated with the aid of the whole-cell voltage-camp technique. Quercetin (0.5-200 microM) stimulated I(Ca,L) in a concentration-dependent manner. The current-voltage (I-V) relationship of I(Ca,L) was slightly shifted to more negative potentials in the presence of quercetin. The EC(50) value of the quercetin-induced stimulation of I(Ca,L) was about 7 microM. The presence of quercetin (5 microM) shifted the steady state inactivation curve of I(Ca,L) to a more negative potential by approximately -10 mV. Although quercetin might increase intracellular cyclic AMP, sp-cAMPS did not affect I(Ca,L). In addition, neither flavone nor wortmannin had any effect on the amplitude of I(Ca,L), while epicatechin and genistein slightly suppressed it. Quercetin (50 microM) decreased the amplitude of tetrodotoxin-sensitive Na(+) current in GH(3) cells. Under current-clamp configuration, quercetin could increase the firing frequency of actions potentials. Conversely, in NG108-15 neuronal cells, quercetin suppressed the amplitude of I(Ca,L). The quercetin-induced inhibition of I(Ca,L) was abolished in NG108-15 cells preincubated with t-butyl hydroperoxide (1 mM). Quercetin-mediated stimulation of I(Ca,L) in GH(3) cells was presumably not associated with the level of intracellular cyclic AMP, or with the activity of tyrosine or phosphoinositide 3-kinases. Therefore, the effects of quercetin on ion currents may, at least in part, contribute to the underlying mechanisms through which it affects neuronal or neuroendocrine function.