Elsevier

Journal of Ethnopharmacology

Volume 127, Issue 2, 3 February 2010, Pages 286-291
Journal of Ethnopharmacology

Safety evaluation of long term oral treatment of methanol sub-fraction of the seeds of Carica papaya as a male contraceptive in albino rats

https://doi.org/10.1016/j.jep.2009.11.007Get rights and content

Abstract

Ethnopharmacological relevance

The manuscript is one of the series of attempts in authenticating scientific documentation of the seeds of Carica papaya being traditionally used for contraception.

Aims of the study

To establish safety of the methanol sub-fraction (MSF) of the seeds of Carica papaya as a male contraceptive following long term oral treatment.

Materials and methods

MSF was administered orally to albino rats at multiples of contraceptive dose (CD) at 50 (1×), 100 (2×), 250 (5×) and 500 (10×) mg/kg body weight daily for 52 weeks. Body weight, organs weight, morbidity, mortality, clinical chemistry, sperm analysis, histopathology and serum testosterone were evaluated to assess the safety and contraceptive efficacy.

Results

MSF treatment at various dose regimens, daily for 52 weeks did not show significant changes in body weight, organs weight, food and water intake and pre-terminal deaths compared to those of control animals. Sperm count and viability in 50 mg/kg body weight treated animals and the weight of epididymis, seminal vesicle and prostate of all the treated animals showed significant reduction compared to control. Cauda epididymal spermatozoa of 50 mg/kg body weight treated animals were immotile. Azoospermia was observed in 100, 250 and 500 mg/kg body weight treated animals. Serum clinical parameters, serum testosterone and histopathology of vital organs were comparable to those of control animals. Histology of testis revealed adverse effects on the process of spermatogenesis, while the histology of epididymis, seminal vesicles and ventral prostate showed no changes compared to control.

Conclusion

The long term daily oral administration of MSF affects sperm parameters without adverse side effects and is clinically safe as a male contraceptive.

Introduction

Carica papaya L. (Caricaceae) is an important medicinal plant in Indian traditional medicine (Nadkarni, 1954, Chopra et al., 1958). The seeds of Carica papaya are reported to possess emmenagogue, abortifacient and antifertility properties (Chopra et al., 1958). The male antifertility property of the seeds of Carica papaya has been well documented (Das, 1980, Chinoy et al., 1985, Chinoy et al., 1995, Chinoy and Padman, 1996, Lohiya et al., 2001, Lohiya et al., 2005a). We have authenticated with series of experiments using different extraction procedures and with different animal models that the methanol sub-fraction (MSF) of the benzene chromatographic fraction of the chloroform extract of the seeds of Carica papaya possess 100% contraceptive efficacy, effected through inhibition of sperm motility in rats and langur monkeys and azoospermia in rabbits, without adverse systemic side effects and has been identified as a putative candidate for male contraception (Lohiya and Goyal, 1992, Lohiya et al., 1999a, Lohiya et al., 1999b, Lohiya et al., 2001, Lohiya et al., 2002, Lohiya et al., 2005b, Lohiya et al., 2008, Pathak et al., 2000, Manivannan et al., 2004). Initial attempts to identify the chemical composition of the MSF through IR, NMR−1 and MS revealed that the product is a homogeneous mixture of long chain fatty esters. The dose regimen of 50 mg/kg body weight/day has been standardized as one contraceptive dose (Lohiya et al., 2001, Lohiya et al., 2005a). Initial safety by single oral administration and daily oral administration up to 90-day period has already been reported (Lohiya et al., 2006). The present investigation is expected to provide necessary information towards clinical safety of MSF for long term use as a male contraceptive.

Section snippets

Test material

Fresh seeds of Carica papaya L. (Caricaceae) of honey dew variety were procured commercially, authenticated in the Department of Botany, University of Rajasthan, Jaipur (Voucher No. RUBL 16590), shade dried, powdered and refluxed with chloroform for 36 h at 58–60 °C. The resultant chloroform extract was subjected to silica gel column chromatography (60–120 mesh), eluted with benzene. The benzene chromatographic fraction of the chloroform extract was concentrated under reduced pressure and

Food and water intake

Food and water intake showed day to day fluctuations and the values were comparable to those of control animals (Data not shown).

Pre-terminal death

Pre-terminal deaths in four males, one each in Group I (Control) and Group III (100 mg) and two in Group IV (250 mg) and three females, two in Group IV (250 mg) and one in Group V (500 mg) were recorded. Autopsy of these animals showed no treatment related mortality, since gross morphology of all the vital organs appeared normal.

Body weight and organs weight

The final body weight of the control and

Discussion

The toxicological severity, through single dose administration and repeated dose administration up to 28 and 90 days up to 10 times the contraceptive doses has already been demonstrated in rats which revealed no treatment related adverse side effects (Lohiya et al., 2006). Limit test with single high dose at 2000 mg/kg body weight over the 14 days observation period also did not detect external toxic symptoms, mortality, morbidity, altered food and water intake, body and organs weight,

Acknowledgements

The investigation was supported by the Indian Council of Medical Research (ICMR), New Delhi. The authors are thankful to the Special Assistance Programme (Phase III)/Centre for Advanced Studies (CAS), University Grants Commission, New Delhi and the Head of the Department, for providing infrastructural facilities.

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