Indian Journal of Pharmacology Medknow Publications on behalf of Indian Pharmacological Society ISSN: 0253-7613 EISSN: 1998-3751 Vol. 38, Num. 2, 2006, pp. 111-114

Indian Journal of Pharmacology, Vol. 38, No. 2, March-April, 2006, pp. 111-114

Research Paper

Antiovulatory and abortifacient potential of the ethanolic extract of roots of Momordica cymbalaria Fenzl in rats

Koneri Raju, Balaraman R*, Saraswati CD

Visveswarapura Institute of Pharmaceutical Sciences, Vokkaligara Sangha Campus,K R Road, Bangalore 560004, *Department of Pharmacy, Faculty of Science and Technology, M.S. University of Baroda, Baroda
Correspondence Address:Visveswarapura Institute of Pharmaceutical Sciences, Vokkaligara Sangha Campus,K R Road, Bangalore 560004, rajukoneri@rediffmail.com

Code Number: ph06028

Abstract

Keywords: Antifertility, contraception, ovulation.

Introduction

Material and Methods

Plant collection and preparation of the extract
Fresh roots of Momordica cymbalaria were collected from Gadag district, Karnataka. They were identified and authenticated by a botonist in the Department of Botany, Bangalore University, Bangalore. A specimen sample of the same was preserved at the herbarium of the Department of Botany, with the voucher no. 18122003, for future reference.

The roots were isolated and chopped into small pieces. Next, they were dried under shade at room temperature for seven days. The dried roots were powdered, passed through sieve (coarse 10/44), and extracted with 95% v/v ethanol using Soxhlet extractor.[6] The combined extracts were concentrated at 40o C to obtain dark brownish yellow residue. The yield obtained from this process was found to be 21.5 % w/w.

Animal
Colony bred female adult albino rats of Wistar strain (150-200 gm) were maintained under controlled standard animal house conditions. They had access to standard rat feed and water ad libitum. All the animal procedures were performed according to the CPCSEA norms. The Institutional Animal Ethics Committee approved the experimental procedures. The acute oral toxicity study was performed using the up and down procedure (OPPT guidelines).

Antiovulatory activity
Vaginal smear from each rat was examined daily for 15 days, and those rats exhibited three regular cycles[7] were included in the study. The selected rats were divided into three groups of six animals each. Drugs and vehicle were started in the estrous phase and administered orally, daily for 15 days. Group I received vehicle only (1%Tween 80, p.o. daily) and served as control. Groups II and III received ethanolic extract at 250 and 500 mg/kg, respectively. The 15-day treatment was to cover three regular estrous cycles. Vaginal smear from each animal was observed every morning between 9-10 A.M. On the 16th day, 24 hours after the last treatment, the animals from each group were sacrificed. Ovaries and uteri were dissected out, freed from extra deposition, and weighed on a sensitive balance (Precisa, XB series). One ovary from each animal was processed for biochemical analysis of cholesterol. The other ovary was fixed in 10% formalin buffer for histological study.

Abortifacient activity
The female rats were caged with male rats of known fertility in the ratio of 2:1 in the evening of proestrous. They were examined the following morning for the presence of sperms. Rats exhibiting thick clumps of spermatozoa in the vaginal smear were separated, and that day was designated as day one of pregnancy. The pregnant rats were divided into three groups of six animals each. Group I received vehicle only (1%Tween 80, p.o. daily) and served as control. Group II and group III received ethanolic extract at 250 and 500 mg/kg, p.o. daily, respectively. The extracts were administered orally through gastric gavage from the 6^th to the 15^th day of pregnancy (period of organogenesis). The animals were laparotomised under light ether anesthesia on the 19^th day of pregnancy. Both horns of the uterus were observed for the number of im-plantation sites, resorptions, and dead and alive fetuses.[9],[10],[11]

The results are expressed as mean±SEM. The statistical significance between groups was analysed using the one-way ANOVA test and the Tukey Kramer multiple comparison post-test. P< 0.05 was considered significant.

Results

Mortality in the acute toxicity test was not seen in the limit test at a dose of 5000 mg/kg. Therefore, 1/10th & 1/20th of the dose were selected for this study.

Ethanolic extract at 250 and 500 mg/kg caused a significant (P< 0.001) decrease in the duration of the estrous and metes-trous phases, no change in the duration of the diestrous phase, and a significant (P< 0.001) increase in the duration of the proestrous phase, compared with the control group. [Table - 1]

Ethanolic extract at 250 and 500 mg/kg significantly (P< 0.01) decreased the weight of ovaries, compared with the control group. [Table - 2] An increase in preovulatory follicles and atretic follicles was seen in the treated groups [Figure - 2][Figure - 3]. A highly significant (P< 0.001) increase in ovarian cholesterol level was observed at 250 mg/kg dose, compared with the control group. [Table - 3]

At 500 mg/kg, ethanolic extract showed a highly significant (P< 0.001) abortifacient effect. At 250 mg /kg, ethanolic extract did not show any abortifacient activity, but reduced the number of viable fetuses and resorptions (6.16±1.24). There was no change in the fetal weight, compared with the control group. Table - 4

Discussion

Many morphological, histological, physiological, and biochemical changes occur in the ovary during the estrous cycle. During the maturation of preovulatory follicles, ovulation takes place under the combined and balanced influence of ovarian and extra ovarian hormones. Imbalance in these hormones leads to irregularity in the ovarian functions and duration of the estrous cycle.[12],[13],[14]

The estrous cycle in the rats treated with extract (250 and 500 mg/kg) showed a decrease in the duration of estrous and the metestrous phases. It was also characterised by a prolongation of the proestrous phase. The prolongation of the proestrous phase indicates that maturation of the follicle in the preovulatory phase was delayed, leading to non-maturation of graffian follicle. Non-availability of matured graffian follicle was indicated by reduction in the estrous and the metastrous phases. Therefore, ovulation was inhibited. This result was further supported by our histopathological studies [Figure - 2][Figure - 3] in which the transverse section of the ovary showed the presence of primary or developing follicles.

Ovary can be considered an aggregate of three endocrine tissues, the stroma, the follicle and the corpus luteum. The weights of these tissues constitute the net weight of the ovary. During the estrous cycle the weight of the ovarian tissue increases under the influence of gonadotrophic and steroidal hormones. The decrease in the weight of ovaries of the rats treated with extract indicates a decrease in the activity of the stroma, the follicle, and the corpus luteum in the ovary. This decrease may be due to the non-availability of gonadotrophic or steroidal hormones or both.[13]

Atretic follicles are degenerating preovulatory follicles. The degeneration of preovulatory follicles takes place due to non-availability of steroidal hormones (essential for their maturation and differentiation), non-availability of local estrogen produced by granulosa cells, or imbalance in endogenous steroid, protein and hormones. The presence of increased atretic follicles in the rats treated with ethanolic extract, compared with control rats, indicates that the extract promotes the degeneration of preovulatory follicles. Cholesterol is the precursor for the steroidogenesis of ovarian endocrine tissues. The significant increase in ovarian cholesterol in the treated group (250 mg/kg) indicates that cholesterol is not used for steroidogenesis.[13] But 500 mg dose did not show a similar effect indicating that it occurs only at a lower dose.

Abortion refers to the premature expulsion of the products of conception from the uterus. Abortion may be due to maternal exposure to chemicals, which can disrupt pregnancy and cause detachment of the embryo.[10] Ethanolic extract at 500 mg/kg showed 100% abortifacient activity, while 250 mg/kg did not show abortifacient activity. However, it reduced the number of viable fetuses.

To conclude a highly significant decrease in the duration of the estrous and the metestrous phases and increase in the duration the proestrous phase was seen. In addition, a highly significant decrease in ovarian weight and increase in cholesterol level, compared with the control group, was noted. These findings indicate that extract Momordica cymbalaria produces temporary inhibition of ovulation. The result of administration of extract to the pregnant rats during organogenesis shows that the extract is abortifacient only at the higher dose of 500 mg. These findings could explain the traditional use of Momordica cymbalaria as abortifacient and antiovulatory[Figure - 1].

References

Copyright 2006 - Indian Journal of Pharmacology

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