Preliminary assessment of Rosmarinus officinalis toxicity on male Wistar rats' organs and reproductive system

Avaliação preliminar da toxicidade de Rosmarinus officinalis no sistema reprodutor e em órgãos de ratos Wistar

ARTIGO

Preliminary assessment of Rosmarinus officinalis toxicity on male Wistar rats' organs and reproductive system

Avaliação preliminar da toxicidade de Rosmarinus officinalis no sistema reprodutor e em órgãos de ratos Wistar

Rita de Cássia da Silveira e Sá^I,*; Magda N. Leite^II; Leandra E.G. Oliveira^III; Melina M. Toledo^I; Tânia C. Greggio^I; Martha O. Guerra^I

^IDepartamento de Biologia, Centro de Biologia da Reprodução, Universidade Federal de Juiz de Fora, 36036-900, Juiz de Fora, Brazil

^IIFaculdade de Farmácia e Bioquímica, Universidade Federal de Juiz de Fora, 36036-970, Juiz de Fora, Brazil

^IIIDepartamento de Ciências Biológicas, Universidade Estadual do Sudoeste da Bahia, 45200-000, Jequié, Brasil

ABSTRACT

Rosemary (Rosmarinus officinalis L. - Lamiaceae) is a shrub used in the treatment of hepatic, intestinal, renal and respiratory affections. Its toxicity was assessed in female rats and an anti-implantation effect was reported after treatment with this plant. This work analyzes the effect of the short-term administration of R. officinalis extract on vital organs, on the organs of the reproductive system and sperm production of mature male Wistar rats. Adult Wistar rats were treated with 1 mL of R. officinalis aqueous extract at a dose level of 291.2 mg and 582.4 mg/kg of body weight for five days. Body and organs weights, sperm production and food consumption were evaluated. The results showed that the lower dose administration of R. officinalis extract did not significantly alter body and organs weight nor did it interfere with gamete production. However, animals treated with the higher dose showed significant weight increase of the seminal vesicle but no significant alteration of the other variables. Food intake was not affected by the treatments.

Keywords: Rosmarinus officinalis, reproductive organs, sperm production, Wistar rats.

RESUMO

Alecrim (Rosmarinus officinalis L. – Lamiaceae) é uma planta utilizada no tratamento de afecções hepática, intestinal, renal e respiratória. Sua toxicidade foi investigada em ratas e seu efeito antiimplantação foi relatado em estudos prévios. Este trabalho analisa o efeito da administração aguda do extrato de R. officinalis em órgãos vitais, em órgãos do sistema reprodutor e na produção de espermatozóides de ratos Wistar adultos. Ratos Wistar foram tratados com 1 mL do extrato aquoso de R. officinalis na dose de 291,2 mg e 582,4 mg/kg de peso corporal por cinco dias. O peso corporal e de órgãos, a produção de espermatozóides e o consumo de ração foram avaliados. Os resultados mostraram que a administração da dose menor do extrato de R. officinalis não alterou significativamente o peso corporal e de órgãos e nem interferiu com a produção de gametas. Entretanto, os animais tratados com a maior dose evidenciaram aumento significativo de peso de vesícula seminal, mas nenhuma outra alteração significativa das outras variáveis. O consumo de ração não foi afetado pelos tratamentos.

Unitermos: Rosmarinus officinalis, órgãos reprodutivos, produção de espermatozóides, rato Wistar.

INTRODUCTION

Medicinal plants have long been used by the peoples of the world for treating their illnesses, but many substances found in them may be harmful to the organism. A large number of plants are known for their teratogenic and abortive properties (Keeler, 1990; Norton, 1996; Mengue et al., 2001) or for their toxic effect on the male reproductive system (Soufir et al., 1989).

There are a number of agents that can have an adverse effect on the male reproductive system, for example by interfering with sexual maturation, the production, and transport of spermatozoa, the spermatogenic cycle, sexual behavior and fertility (Kimmel et al., 1995). The action of a toxic agent in the testis may cause a reduction in the sperm concentration and the production of abnormal gametes (Sundaram; Witorsh, 1995). It may also play an adverse role on the Leydig cell, affecting testosterone production (Mooradian et al., 1987). Various studies have reported the toxic effect of agents in the epididymis (Tsunoda; Chang, 1976; Working et al., 1985a,b; Klinefelter et al., 1990; Vieira-Filho et al., 2002), by disturbing the sperm maturation process, and the functioning of the accessory sex glands (Zenick et al., 1994).

Rosmarinus officinalis L., popularly known as rosemary, is a perennial bush of the family Lamiaceae employed in folk medicine for treating hepatic, intestinal, renal and respiratory affections. It is also known for its emmenagogue, colagogue, antispasmodic activities (Camargo, 1985; Santos, et al., 1988; Lemonica et al., 1996; Al-Sereiti et al., 1999; Martins et al., 2000; Tôrres et al., 2005) and as an abortifacient (Laszlo; Henshaw, 1954; Watt; Breyer-Branwijk, 1962). Pharmacological investigations have shown that the aqueous extract of R. officinalis possess diuretic effect in rats (Haloui et al., 2000); the methanolic extract inhibits the motility of Tripanosoma cruzi epimastigots (Abe et al., 2002), the hydroalcoholic extract exhibits anti-ulcerogenic (Dias et al., 2000) and hepatoprotective activities (Hoefler et al., 1987; Fahim et al., 1999; Sotelo-Félix et al., 2002, Amin; Hamzer, 2005), antimicrobial activity (Lima et al., 2006), inhibitor of a-amylase activity (Funke; Melzig, 2006), inhibitor of the enzyme acetylcholinesterase (Barbosa-Filho et al., 2006) and inhibits skin (Huang et al., 1994) and mammary (Singletary; Nelshoppen, 1991) tumorigenesis.

Phytochemical studies revealed the presence of several compounds in R. officinalis including phenolic diterpenes (Thorsen; Hildebrandt, 2003) such as carnosol and carnosic acid (Aruoma et al., 1992), diterpenoid quinines (Mahmoud et al., 2005), rosmarinic acid (Maris; Giovanni, 1958), flavonoids (Guilbert; Bezanger, 1970), rosmaricine (Yakhontova; Kuzovkov, 1963) and essential oils (Dmitriev et al., 1988). Carnosol, carnosic acid and rosmarinic acid were found to possess strong antioxidative activity whereas essential oils showed antimicrobial (Larrondo et al., 1995; Mangena; Muyima, 1999) and antifungic activities (Larrondo et al., 1995). Flavonoids have been shown to produce antiandrogenic activity and affect fertility in male dogs (Bhargava, 1989).

Previous studies have investigated R. officinalis actions on the female reproductive system. Damasco and Lemonica (1999) reported a high incidence of anomalous embryos in rats treated with 260 mg/kg^-1 of rosemary ethanolic extract from the first to the fourth day of gestation. A higher dose (1040 mg/kg^-1) administered during the same period reduced the number of blastocysts found in the uterus. After continuous administration from the first to the sixth day and from the sixth to the fifteenth day of gestation, Lemonica et al. (1996) reported the embryotoxic effect on the pre-implantation period and the absence of any significant developmental alteration after this period. It was suggested that the embryotoxic effects, which led to implantation impairment, were due to morphological alterations in the embryos, hormonal alterations or reduction of motility in the oviduct.

Considering the presence of substances with antifertility activity, its toxic effect on the female reproductive system, and the fact that no information has been found in the literature about the effects of R. officinalis on the male reproductive system, this preliminary work had the purpose of investigating the effects of the short-term exposure to R. officinalis on vital organs, the reproductive system, and sperm production of the Wistar rat. Short-term tests are of value in the identification of target sites, affected cells, and mechanisms of toxicity (Zenick et al., 1994).

MATERIAL AND METHODS

Plant material and extraction

R. officinalis L. was collected in the botanical garden of the Pharmacy and Biochemistry Faculty, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, MG, Brazil, and authenticated by Dr. Fátima Regina Gonçalves Salimena in the Herbarium Leopoldo Krieger, Department of Botany, (UFJF), where a voucher specimen registered under the number CESJ 45407 is deposited. The aqueous extract was prepared using aerial parts of this plant. Dried and powdered aerial parts underwent maceration for 24 hours followed by exhaustive percolation. On both processes distilled water was used as the extractor fluid. After percolation, the material was transferred to a rotavapor in order to reduce the water volume and obtain the final concentration (72.8 mg/mL) of the extract.

Animals

Ninety-day-old adult male Wistar rats (Rattus norvegicus Berkenhout, 1769), weighing around 250 g, were obtained from the vivarium of UFJF, where they were born and bred. They were housed individually under standard laboratory conditions with a 12 h light/12 h dark photoperiod. They were fed on rat chow pellets and received water ad libitum. Animal care and the experimental protocol followed the principles and guidelines suggested by the Brazilian College of Animal Experimentation (COBEA) and were approved by the Ethical Committee of the Federal University of Juiz de Fora (UFJF) (protocol number 003/2004 – CEA).

Experimental procedure

The rats were randomly distributed into three treatment groups (T1, T2 and T3) and their respective control groups (C1, C2 and C3), and were submitted to the 2.5-week reproductive toxicity test protocol described by Linder et al. (1992). Each animal from the treatment groups T1 and T2 received, by gavage and once daily, 1 mL of the R. officinalis aqueous extract at a dose level of 291.2 mg/kg of body weight for five days whereas animals from the group T3 were treated with twice the dose (582.4 mg/kg of body weight). The control groups received 1 mL of distilled water, following the same protocols as the treatment groups.

During the experiment, the animals were inspected daily for detection of clinical signs of toxicity, such as piloerection, and alterations in locomotor activity (Mason; Kang, 1994). Body weight was recorded before the beginning of treatment, every two days and at the end of treatment. Food consumption was monitored daily. The animals were killed by an overdose of anesthetic three (groups C1 and T1, C3 and T3) and 14 days (groups C2 and T2) after the end of treatment. Immediately after death, the animals underwent laparotomy for removal and posterior weighing of the following organs: testes, left epididymis, seminal vesicle, prostate, liver, kidneys, lungs, brain and pituitary gland.

Sperm were collected from the epididymal secretion of the right epididymis cauda. The secretion was placed in a 0.3 mL drop of physiological serum and later diluted in distilled water. From this homogenate, a sample was taken and the number of sperm counted using a hemocytometer with improved double Neubauer ruling (Moraes, 1994).

Statistical analysis

The data were analyzed using the Student's t test and the Mann-Whitney test (a = 0.05) (Sokal; Rohlf, 1995) and were expressed by mean and standard deviation (SD).

RESULTS AND DISCUSSION

The diverse therapeutic properties of R. officinalis has incremented its use by the population (Ruppelt et al., 1990; Cruz et al., 1996), however the presence of chemical compounds, such as flavonoids, that have been reported to have toxic (Bhargava, 1989; Ulubelen et al., 1994; Born et al., 2000) and antifertility activities (Vilegas et al., 1997; Martins et al., 2000) as well as the anti-implantation effect reported on female rats (Lemonica et al., 1996) suggests a potential reproductive toxic role of this plant.

This study was carried out to make a preliminary investigation of R. officinalis toxicity by the use of short duration protocols as they are useful tools for identifying compounds with potential to affect the male reproductive system and spermatogenesis (Chan; Hayes, 1994; Linder et al., 1990, 1992, 1994), allowing the identification of target organs, affected cells and the toxicity mechanisms of compounds (Clegg et al., 2001). These are important approaches for assessing male reproductive risk, and, according to Zenick et al. (1994), such delineation may be impossible after subchronic treatment. In this work, adult male Wistar rats were submitted to a short-term exposure to R. officinalis aqueous extract at a dose level 9 times (291.2 mg/kg of body weight) and 18 times (582.4 mg/kg of body weight) greater than the human dose.

During the experimental procedure, no deaths, locomotor activity alteration, piloerection or any other clinical signs of toxicity such as were observed in any of the groups. Body weight did not change significantly (Figures 1, ³ and ⁵) and the treatment did not interfere with food consumption (Figures 2, ⁴ and ⁶).

The results show that the administration of the lower dose (291.2 mg/kg of body weight) of R. officinalis with death occurring at three and 14 days after the end of treatment did not produce any significant weight alteration in the organs of the reproductive system, the accessory glands, liver, kidneys, lungs, brain and pituitary gland (Tables 1 and 2). However, the administration of twice the dose (582.4 mg/kg of body weight) resulted in a significant weight increase of the seminal vesicle of the treated rats whereas the weights of the other organs analyzed were not significantly altered (Table 3) (Dimech et al., 2006).

An increase in the weight of reproductive organs is under hormonal control and could suggest a disturbance of the reproductive endocrine functions (Elbetieha et al., 2001). The pituitary gland is responsible for the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which act on the testes. Any damage to this gland could interfere with the male reproductive system, thus affecting the production of sex steroid hormones and male gametes (Mahony; Hodgen, 1995). In addition to the endocrine influence, the adverse effect of a substance on the epididymal sperm number is also a potential indicator of reproductive toxicity (Blazak et al., 1985). In this work, despite the weight increase of the seminal vesicle no significant weight gain or loss was detected in the pituitary gland. The cauda epididymis sperm number did not differ between treated and control animals (Figure 7), suggesting that the weight increase of the seminal vesicle is not related to a toxic action of R. officinalis extract on the functioning of the pituitary gland.

CONCLUSIONS

Our preliminary assessment of possible male reproductive toxicity of R. officinalis administered to mature male Wistar rats showed an adverse effect on the seminal vesicle but indicates that there are no toxic effects on the testis, epididymis and prostate. No interference with the spermatogenic cycle and consequently with gamete production was detected considering the acute reproductive test protocol employed in this work. However, further studies adopting chronic protocols should be applied to investigate the effect of different doses over several spermatogenic cycles in order to obtain more conclusive results about this plant toxicity and antifertility activity.

ACKNOWLEDGEMENTS

This research was supported by BIC/UFJF. The authors are grateful to Paulo Sérgio do Carmo for the technical assistance.

Received 12/15/05

Accepted 03/26/06

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Publication Dates

• Publication in this collection
  28 Jan 2008
• Date of issue
  Sept 2006

History

• Accepted
  26 Mar 2006
• Received
  15 Dec 2005