Post-Coital Antifertility Activity of Hibiscus rosa-sinensis Linn. roots

A Critical Review and Scientific Prospective on Contraceptive Therapeutics from Ayurveda and Allied Ancient Knowledge

Commonly used synthetic or prescribed hormonal drugs are known to interfere with the endocrine system and may have adverse reproductive, neurological, developmental, and metabolic effects in the body. These may also produce adverse effects such as polycystic ovarian disorder, endometriosis, early puberty, infertility or toxicity to gonads, testicular germ cell cancer, breast or prostate cancer, brain developmental problems, and even birth defects. Globally, the emergence of renewed interest in natural products for reproductive health is on the rise, which offers opportunities for new contraceptive developments. The search for alternate, safer contraceptive products or agents of natural origin is of scientific interest. Ayurvedic classical texts offer knowledge and information about the reproductive function and therapeutics including those for enhancement and limiting male and female fertility. Review of ancient, medieval, and recent—including texts on erotica that provide information on approaches and large numbers of formulations and drugs of plant, mineral or animal origin—claimed to have sterilizing, contraceptive, abortifacient, and related properties is presented. Few among these are known to be toxic and few are not so common. However, most of the formulations, ingredients, or modes of administration have remained unattended to, due to issues related to consumer compliance and limitations of standardization and lack of appropriate validation modalities. Several of these ingredients have been studied for their phytoconstituents and for the variety of pharmacological activities. Efforts to standardize several classical dosage forms and attempts to adapt to modern technologies have been made. List of formulations, ingredients, and their properties linked with known constituents, pharmacological, biological, and toxicity studies have been provided in a series of tables. The possible effectiveness and safety of selected formulations and ingredients have been examined. Suggestions based on new drug delivery systems integrated with advances in biotechnology, to provide prospects for new therapeutics for contraception, have been considered. Ayurveda is built on a holistic paradigm of biological entity rather than limited gonadal functions. Graphic presentation of a few carefully chosen possibilities has been depicted. New approaches to standardization and ethnopharmacological validation of natural contraceptive therapeutics may offer novel mechanisms and modalities and therapeutic opportunities to satisfy unmet needs of contraception.

Beneficial effects of Hibiscus rosa-sinensis L. flower aqueous extract in pregnant rats with diabetes

Purpose

The Hibiscus rosa-sinensis flower is widely used in Brazilian traditional medicine for the treatment of diabetes and has shown antifertility activity in female Wistar rats. However, there is no scientific confirmation of its effect on diabetes and pregnancy. The aim of this study was evaluate the effect of aqueous extract of H. rosa-sinensis flowers on maternal-fetal outcome in pregnant rats with diabetes.

Methods

Diabetes was induced by streptozotocin (STZ, 40 mg/kg) in virgin, adult, female Wistar rats. After diabetes induction, the rats were mated. The pregnant rats were distributed into four groups (n minimum = 11 animals/group): non-diabetic, non-diabetic treated, diabetic, and diabetic treated. Oral aqueous extract of Hibiscus rosa-sinensis was administered to rats in the treatment groups during pregnancy. At term pregnancy, maternal reproductive outcomes, fetal parameters, and biochemical parameters were analyzed.

Results

The non-diabetic treated group showed decreased high density lipoprotein cholesterol, increased atherogenic index (AI) and coronary artery risk index (CRI), and increased preimplantation loss rate compared to the non-diabetic group. Although treatment with H. rosa-sinensis led to no toxicity, it showed deleterious effects on cardiac and reproductive functions. However, the diabetic treated group showed increased maternal and fetal weights, reduced AI and CRI, and reduced preimplantation loss rate compared to the untreated diabetic group.

Conclusion

Our results demonstrate beneficial effects of this flower only in pregnant rats with diabetes and their offspring. Although these findings cannot be extrapolated to human clinical use, they show that the indiscriminate intake of H. rosa-sinensis may be harmful to healthy individuals and its use should be completely avoided in pregnancy.

Assessment of an aqueous seed extract of Parkia clappertoniana on reproductive performance and toxicity in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

The seeds of Parkia clappertoniana Keay (Family: Fabaceae) are extensively used in food in the form of a local condiment called 'Dawadawa' in Ghana and consumed by all class of people including sensitive groups such as pregnant women and children. Also, crudely pounded preparations of P. clappertoniana seeds are used as labor inducing agent in farm animals by local farmers across northern Ghana where nomadism is the livelihood of most indigenes. Ecologically, P. clappertoniana is extensively distributed across the savannah ecological zone of many African countries where just like Ghana it enjoys ethnobotanical usage. Although, many studies have investigated some aspects of the pharmacological activity of P. clappertoniana, none of these studies focused on the reproductive system, particularly its effects on reproductive performance and toxicity. To contribute, this study assessed the effect of aqueous seed extract of P. clappertoniana (PCE) on reproductive performance and toxicity in Sprague-Dawley rats and ICR mice.

METHODS

After preparation of PCE, it was then tested on rodents at different gestational and developmental windows (1-7, 8-14, and 15-term gestational days) to assess the following: mating behavior, implantation rate, maternal and developmental toxicities. Generally, animals were randomly grouped into five and treated as follows: normal saline group (5ml/kg po), cytotec (misoprostol) group (200mg/kg po), folic acid group (5mg/kg po), and PCE groups (100, 200, and 500mg/kg po), however, these groupings were varied to suit the specific requirements of some parameters. For acute toxicity, animals were orally administered PCE (3 and 5g/kg for mice and rats respectively).

RESULTS

PCE-treated rats showed improved mating behavior compared to control rats. PCE improved implantation rate compared to misoprostol-treated rats. On the average, PCE-treated rats delivered termed live pubs at 21 days compared to that of folic acid-treated rats at 23 days. Also, PCE-treated rats showed no observable maternal and developmental toxicities compared to folic acid and control rats. PCE (3-5g/kg po) was orally tolerated in rodents.

CONCLUSION

Oral administration of Parkia clappertoniana seed extract improves reproductive performance in rodents with no observable maternal and developmental toxicity.

Aqueous extracts of Mozambican plants as alternative and environmentally safe acid-base indicators

Indicators are substances that change color as the pH of the medium. Many of these substances are dyes of synthetic origin. The mulala plant (Euclea natalensis), which roots are commonly used by rural communities for their oral hygiene, and roseira (Hibiscus rosa-sinensis), an ornamental plant, are abundant in Mozambique. Currently, synthetic acid-base indicators are most commonly used but have environmental implications and, on the other hand, are expensive products, so the demand for natural indicators started. This study investigated the applicability of aqueous extracts of H. rosa-sinensis and E. natalensis as acid-base indicators. Ground on this work, the extracts can be used as acid-base indicators. On the basis of the absorption spectroscopy in both the UV-Vis region and previous studies, it was possible to preliminarily pinpoint anthocyanins and naphthoquinones as responsible for the shifting of colors depending on the pH range of aqueous extracts of H. rosa-sinensis and E. natalensis. These natural indicators are easily accessible, inexpensive, easy to extract, environmentally safe, and locally available.

Switching to instant black coffee modulates sodium selenite-induced cataract in rats

The influence of daily consumption of some common beverages on the development of cataract in rats was investigated. Total phenol content was determined in the beverages and an oral standardized dose of total phenols from each beverage was given to the treated rats. Weaned male albino rats were used and divided into five groups (n=7). Rats were fed Ain 93G and administered the standardized dose of instant coffee, black tea and hibiscus beverages for 30 days. On day 14 all rats were injected with a single dose of sodium selenite (Na₂SeO₃) 15 µmol/kg bodyweight, except the control groups NC (negative control, did not receive Na₂SeO₃) and PC (positive control, was already injected on day 1 of the study). The rats were continued on Ain 93G and the standardized dose for another 16 days. Positive control rats were used. Total phenols were 210, 40, and 44 mg/g dry weight gallic acid equivalent in black coffee, black tea, and hibiscus, respectively. Decreased levels (statistically significant P<0.05) of malondialdehyde, total nitric oxide, Ca-ATPase, tumor necrosis factor-α, interleukin-1β, superoxide dismutase, and conversely, increased levels (statistically significant P<0.05) of total protein, reduced glutathione, catalase were found in the lenses of the coffee group compared to PC. There are co-phenol substances in the instant black coffee that promoted coffee to be the most effective beverage.

In vitro-assessment of putative antiprogestin activities of phytochemicals and synthetic UV absorbers in human endometrial Ishikawa cells

Critical steps of embryo implantation are controlled by progesterone. These processes can be interrupted by progesterone receptor (PR) antagonists, e.g. drugs used for abortion. Antiprogestin effects induced by natural compounds and environmental chemicals have been rarely addressed. In our in vitro study, we investigated putative antiprogestin activities of the plant compounds apigenin (API) and trans-ferulic acid (t-FA) as well as the UV absorbers octyl methoxycinnamate (OMC) and 4-methylbenzylidene camphor (4-MBC). They were compared with the selective progesterone receptor modulators (SPRMs) mifepristone (RU486) and ulipristal acetate (UPA) as well as the full PR-antagonist ZK137316. Effects of test compounds in combination with progesterone on the progesterone-sensitive target gene estrogen sulfotransferase (SULT1E1) were characterized by sigmoidal concentration-response curves obtained by RT-qPCR. The agonistic effect of progesterone on SULT1E1 mRNA levels was concentration-dependently antagonized by RU486, UPA and ZK137316 as well as, with lower potency, apigenin. t-FA, OMC and 4-MBC had no effect on SULT1E1 mRNA levels. We demonstrated that apigenin, although at higher concentrations, exerts a similar effect as the well-characterized SPRMs RU486 and UPA or the progesterone antagonist ZK137316 in this model. Our endometrium-specific Ishikawa cell assay is a useful complement to artificial transactivation assays for the identification of environmental substances with antiprogestin activities.

An anthocyanin-rich extract from Hibiscus sabdariffa linnaeus inhibits N-nitrosomethylurea-induced leukemia in rats

A previous study reported that anthocyanins from roselle (Hibiscus sabdariffa L.) showed significant anticancer activity in human promyelocytic leukemia cells. To explore the antitumor effect of anthocyanin, a roselle bioactive polyphenol in a rat model of chemical-induced leukemia was assayed. Anthocyanin extract of roselle (Hibiscus anthocyanins, HAs) was supplemented in the diet (0.1 and 0.2%). This study was carried out to evaluate the protective effect of HAs on N-nitrosomethylurea (NMU)-induced leukemia of rats. The study employed male Sprague-Dawley rats (n = 48), and leukemia was induced by intravenous injection of 35 mg kg(-1) body weight of NMU dissolved in physiologic saline solution. The rats were divided into four groups (n = 12): control, NMU only, and HAs groups that received different doses of HAs (0.1 and 0.2%) daily, orally, after NMU injection. After 220 days, the animals were killed, and the following parameters were assessed: morphological observation, hematology examination, histopathological assessment, and biochemical assay. When compared with the NMU-only group, HAs significantly prevented loss of organ weight and ameliorated the impairment of morphology, hematology, and histopathology. Treatment with HAs caused reduction in the levels of AST, ALT, uric acid, and MPO. Also, the results showed that oral administration of HAs (0.2%) remarkably inhibited progression of NMU-induced leukemia by approximately 33.3% in rats. This is the first report to demonstrate that the sequential administration of HAs followed by NMU resulted in an antileukemic activity in vivo.

Medicinal plants for women's healthcare in southeast Asia: a meta-analysis of their traditional use, chemical constituents, and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

This is an extensive review of plants used traditionally for women's healthcare in Southeast Asia and surrounding countries. Medicinal plants have a significant role in women's healthcare in many rural areas of the world. Plants with numerous efficacious observations have historically been used as a starting point in the development of new drugs, and a large percentage of modern pharmaceuticals have been derived from medicinal plants.

MATERIALS AND METHODS

A review was conducted for all plant use mentioned specifically for female healthcare, such as medicine to increase fertility, induce menstruation or abortion, ease pregnancy and parturition, reduce menstrual bleeding and postpartum hemorrhage, alleviate menstrual, parturition and postpartum pain, increase or inhibit lactation, and treat mastitis and uterine prolapse, in 200 studies focusing on medicinal plant use, either general studies or studies focusing specifically on women's healthcare.

RESULTS

Nearly 2000 different plant species are reported to be used in over 5000 combinations. Most common are Achyranthes aspera, Artemisia vulgaris, Blumea balsamifera, Carica papaya, Curcuma longa, Hibiscus rosa-sinensis, Leonurus japonicus, Psidium guajava and Ricinus communis, and each of these species had been reported in more than 10 different scientific articles.

CONCLUSIONS

This review provides a basis for traditional plant use in women's healthcare, and these species can be used as the starting point in the discovery of new drugs.

Antifertility effects of Pouzolzia mixta in female Wistar rats

The continued use of plants by women to prevent pregnancy suggests there are plants out there with potential use as contraceptives. In Zimbabwe, Pouzolzia mixta is used as a "morning after" contraceptive, thus it may possess postcoital antifertility activity. To test contraceptive activity, animals (n=8/group) were orally pretreated with aqueous (AqPM) or ethanolic (EtPM) extract of P. mixta at 300mg/kg b.wt for 7 days followed by mating with continued treatment for 10 days post-conception. To test for postcoital activity, treatment was initiated on day-1 of pregnancy and continued for 10 days. Laparotomy was performed and implantations counted. For estrogenic activity, immature ovariectomised rats were treated for 7 days after which vaginal opening and uterine weights were determined. In vitro oxytocic effects were performed using uterine tissue in an organ bath with De Jalon's solution. Acetylcholine (Ach) was the positive control. Results showed modest contraceptive activity with EtPM more effective in inhibiting fertility compared to AqPM (37.5% vs 25%) with a similar trend for antiimplantation effects (31% vs 19%). There was potent postcoital antifertility effects with AqPM more effective in inhibiting implantation (94.6% vs 86%) and fertility (87.5% vs 75%) compared to EtPM. Immature rat bioassay for estrogenic activity demonstrated pronounced estrogenic activity by both extracts. Oxytocic effects at 400ng/ml were more pronounced for the AqPM (92% of 100ng/ml Ach) than EtPM (25% of 100ng/ml Ach). Findings demonstrate the antifertility effects of aqueous and ethanolic extracts of P. mixta. The antifertility effects may be attributed to antiimplantation, estrogenic and oxytocic effects of the plant extracts.

Fertility control of rodent pests: a review of the inhibitory effects of plant extracts on ovarian function

BACKGROUND

Plant extracts can inhibit fertility by adversely affecting, directly or indirectly, reproductive processes ranging from gonadal function and development to gestation. This review focuses on plant extracts that disrupt ovarian function in rodents.

RESULTS

Extracts from at least 40 plant species exert some of their disruptive reproductive effects at the ovarian level. Of those, 13 plants induce a reduction in the number and type of ovarian follicles and also cause disruption to the oestrous cycle. Their effects are short term and reversible once treatment ceases.

CONCLUSIONS

Protection of plant extracts to prevent their degradation before uptake in the gastrointestinal tract could enhance short-term efficacy but would not enhance the longevity of their effects. Identification and further testing of the specific chemicals responsible for reproductive effects would be beneficial. The adoption of a standard protocol for treatment and assessment of the inhibitory effects of potential control agents on reproductive function in rodents is essential. Treatment with higher concentrations of extracts in conjunction with other extracts or with other chemosterilants could have potential complementary effects and lead to more rapid and permanent changes in ovarian function. An orally delivered agent(s) that causes major depletion of all follicle types, and particularly of non-regenerating primordial follicles, could be an ideal fertility control product and serve as an additional tool for population control of pest rodents.

Potential antifertility agents from plants: a comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional medicines are practiced worldwide for regulation fertility since ancient times. This review provides a comprehensive summary of medicinal flora inhabitating throughout the world regarding their traditional usage by various tribes/ethnic groups for fertility regulation in females.

MATERIALS AND METHODS

Bibliographic investigation was carried out by analyzing classical text books and peer reviewed papers, consulting worldwide accepted scientific databases from the last six decades. Plants/their parts/extracts traditionally used for abortion, contraception, emmenagogue and sterilization purposes have been considered as antifertility agents. Research status of selected potential plant species has been discussed. Further, compounds isolated from plants with attributed fertility regulating potentials are also classified into three categories: (a) phytoconstituents with anti-implantation activity, (b) phytoconstituents with abortifacient activity and (c) phytoconstituents with contraceptive activity.

RESULTS

577 plant species belonging to 122 families, traditionally used in fertility regulation in females, have been recorded, of which 298 plants have been mentioned as abortifacients (42%), 188 as contraceptives (31%), 149 as emmenagogues (24%), and 17 as sterilizers. Among 122 plant families, fabaceae constitutes 49.2%, asteraceae 40.98%, euphorbiaceae 19.7%, apiaceae 16.4%, poaceae 12.3%, labiateae 11.5%, and others in lesser proportion. Various plant parts used in fertility regulation include leaves (25%), roots (22%), fruits (15%), seeds (12%), stem/stem bark (37%), and flowers (4%). Some active compounds, isolated from about various plant species, have been reported to possess significant antifertility potential.

CONCLUSION

This review clearly indicates that it is time to increase the number of experimental studies to find out novel potential chemical entities from such a vast array of unexploited plants having traditional role in fertility regulation. Also, the mechanisms of action by which plant extracts and their active compounds exert antifertility effects remain to be studied.

In silico identification of drug targets for antifertility from natural products by differential reaction content analysis of metabolic pathways

BACKGROUND

One of the major concerns of governments of developing and developed countries is to have a check on their population increase. Realising the importance of avoiding the harmful effects of synthetic compounds, scientists and researchers throughout the world are cooperating in efforts to design new and effective contraceptives from compounds of plant origin.

METHODS

In this paper, we compared 11 plant species by analysing compounds showing antifertility properties with respect to the metabolic pathways involved. The Kyoto Encyclopedia of Genes and Genome pathway database was the source of metabolic pathway information. Protein sequences and classification numbers of unique enzymes exclusively present in certain species were identified using the Expert Protein Analysis System.

RESULTS

Two enzymes, namely, L-aspartate dehydrogenase (EC no. 1.4.1.21) and trans-hexaprenyltranstransferase (EC no. 2.5.1.30), were identified as novel drug targets from the metabolic pathway analysis. Validation of the essential proteins identified through metabolic pathway comparison was done based on the literature information.

CONCLUSION

The in silico analysis resulted in identification of 2 enzymes that are predicted to be the targets for putative antifertility drug. These enzymes can further be modelled to obtain their 3-dimensional structures with the help of various protein structure modelling softwares.

Evaluation of In Vitro Uterotonic Activities of Fruit Extracts of Ficus asperifolia in Rats

The aim of the present study was to determine the uterotonic activities of Ficus asperifolia and investigate its mechanism. The effects of aqueous and methanol extracts of the dried fruits of F. asperifolia (0.05–1.60 mg mL⁻¹) were evaluated on estrogenized isolated rat uterus in the presence and absence of atropine (1.73–55.27 nM), pyrilamine maleate (1.25 × 10⁻³ to 40 × 10⁻³ M), indomethacin (0.06 × 10⁻⁵ to 2.00 × 10⁻⁵ M) or hexamethonium (0.66 × 10⁻⁴ to 21.43 × 10⁻⁴ M). Aqueous (EC₅₀, 0.36 mg mL⁻¹) and methanol (EC₅₀, 0.22 mg mL⁻¹) extracts as well as oxytocin (EC₅₀, 0.02 nM), acetylcholine (EC₅₀, 7.87 nM) and histamine (EC₅₀, 0.76 nM) evoked concentration-dependent contractions of the uterus. Atropine, pyrilamine maleate and indomethacin concentration dependently blocked the response of the uterus to acetylcholine (IC₅₀, 4.82 nM), histamine (IC₅₀, 2.49 nM) and oxytocin (IC₅₀, 0.07 nM), respectively, and to aqueous extract. Hexamethonium produced graded decreases in oxytocin-induced uterine contractions (IC₅₀, 0.37 μM), but did not prevent the contractile effects of the aqueous extract (IC₅₀, 9.88 μM). These results suggest that F. asperifolia-induced uterotonic effect is related to the release of prostaglandins and contraction of the myometrial cells through muscarinic, oxytocic and H₁ histamine receptors. These data further give added value to the ethnic use of F. asperifolia for its abortificient and contraceptive properties.

Hemidesmus indicus and Hibiscus rosa-sinensis Affect Ischemia Reperfusion Injury in Isolated Rat Hearts

Hemidesmus indicus (L.) R. Br. (HI) and Hibiscus rosa-sinensis L. (HRS) are widely used traditional medicine. We investigated cardioprotective effects of these plants applied for 15 min at concentrations of 90, 180, and 360 μg/mL in Langendorff-perfused rat hearts prior to 25-min global ischemia/120-min reperfusion (I/R). Functional recovery (left ventricular developed pressure—LVDP, and rate of development of pressure), reperfusion arrhythmias, and infarct size (TTC staining) served as the endpoints. A transient increase in LVDP (32%–75%) occurred at all concentrations of HI, while coronary flow (CF) was significantly increased after HI 180 and 360. Only a moderate increase in LVDP (21% and 55%) and a tendency to increase CF was observed at HRS 180 and 360. HI and HRS at 180 and 360 significantly improved postischemic recovery of LVDP. Both the drugs dose-dependently reduced the numbers of ectopic beats and duration of ventricular tachycardia. The size of infarction was significantly decreased by HI 360, while HRS significantly reduced the infarct size at all concentrations in a dose-dependent manner. Thus, it can be concluded that HI might cause vasodilation, positive inotropic effect, and cardioprotection, while HRS might cause these effects at higher concentrations. However, further study is needed to elucidate the exact mechanism of their actions.

Neuroprotective effect of Hibiscus rosa sinensis in an oxidative stress model of cerebral post-ischemic reperfusion injury in rats

CONTEXT

The ischemic brain lesions induced in rats by temporary occlusion of the bilateral common carotid arteries and restoration of blood flow to an ischemic brain region is associated with generation of reactive oxygen species with consequent reperfusion injury.

OBJECTIVE

The present study investigated the neuroprotective potential of Hibiscus rosa sinensis L. (Malvaceae) in a bilateral common carotid artery (BCCA) occlusion model of global cerebral ischemic reperfusion.

MATERIALS AND METHODS

The animals underwent 30 min BCCA occlusion and 45 min reperfusion. The methanol extract of H. sinensis (100, 200, 300 mg/kg/day for 6 days, p.o.) was administered 30 min before induction of BCCA occlusion.

RESULTS

The bilateral common carotid artery occlusion resulted in increase in lipid peroxidation, and reduction in superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GSH) activity. The extract attenuated the ischemic reperfusion-induced increase in lipid peroxidation and fall in SOD, CAT, and GSH levels. The cerebral hypoperfusion caused a propensity towards anxiety and was accompanied by deficits of learning and memory. The extract ameliorated anxiety and there was improvement of learning and memory.

DISCUSSION

The administration of H. sinensis prevented the oxidative stress and the biochemical changes associated with cerebral ischemic reperfusion injury. The mechanism of such protection of H. sinensis may be due to cerebral adaptation, through augmentation of cellular antioxidants such as GSH, SOD and CAT. The results suggest the protective role of H. sinensis in ischemic reperfusion injury.

CONCLUSION

This study indicates the beneficial role of H. sinensis in cerebrovascular insufficiency states and dementia.