A postmenopause-like model of ovariectomized Wistar rats to identify active principles of Erythrina lysistemon (Fabaceae)

Inhibition of pro-inflammatory cytokines by selected southern African medicinal plants in LPS-stimulated RAW 264.7 macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Bark is frequently used in southern African traditional medicine to treat inflammation, yet it remains to be rigorously examined for its immunological and anti-inflammatory activity.

AIM OF THE STUDY

Barks obtained from ten important and popular southern Africa plants were evaluated for their anti-inflammatory and immunomodulatory properties against the secretion of some pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, tumour necrosis factor-α (TNF-α), and interferon-gamma (IFN-γ) as well as chemokines (monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein (MIP)-2) in murine RAW 264.7 macrophages.

MATERIALS AND METHODS

The inhibitory effects of aqueous and ethanol extracts were determined using cytokine multiplex-bead assays in lipopolysaccharide (LPS)-stimulated and unstimulated RAW 264.7 cells.

RESULTS

Overall, the ethanol extracts were more potent cytokine inhibitors compared to the aqueous extracts. The LPS-stimulated cells treated with the ethanol extracts of Erythrina lysistemon Hutch., Pterocelastrus rostratus Walp. Syzygium cordatum Hochst. ex Krauss and Warburgia salutaris (G. Bertol.) Chiov., demonstrated significant (p < 0.005) inhibition up to 85% of IL-1β, IL-6, and TNF-α secretion compared to the LPS control. Additionally, P. rostratus and S. cordatum aqueous bark extracts substantially decreased the secretion of all the tested cytokines and chemokines. Chemical investigation of the S. cordatum extract resulted in the identification of four ellagic acid derivatives: ellagic acid 4-O-α-rhamnopyranoside (1), ellagic acid 4-O-α-4″-acetylrhamnopyranoside (2), 3-O-methylellagic acid 4'-O-α-3″-O-acetylrhamnopyranoside (3) and 3-O-methylellagic acid 4'-O-α-4″-O-acetylrhamnopyranoside (4), along with mixtures of ellagic acid 4-O-α-2″-acetylrhamnopyranoside (5), ellagic acid 4-O-α-3″-acetylrhamnopyranoside (6) and ellagic acid (7). Their structures were confirmed by mass spectrometry, NMR spectroscopy, and comparison with data from literature.

CONCLUSION

The cytokine inhibition properties of most of the medicinal plants screened herein are reported for the first time. Our results provide insights into the mechanism of action by which the selected southern African medicinal plants regulate inflammation.

Allium ampeloprasum var. Porrum (Alliaceae) Improves Metabolic and Reproductive Disorders Associated with Polycystic Ovary Syndrome in Wistar Rats

To provide scientific evidence of the efficacy of Allium ampeloprasum against female infertility, the effects of the aqueous extract of the said plant (AE) were evaluated in rats with letrozole-induced polycystic ovary syndrome (PCOS). AE was administered orally to PCOS rats at doses of 192, 384, and 768 mg/kg. The positive control was co-treated with clomiphene citrate (1 mg/kg) and metformin (200 mg/kg). Normal and negative controls received distilled water. The vaginal contents of rats were examined daily under a microscope before (7 days) and during treatment. Treatments were administered orally for 15 days, and then, 6 rats from each group were sacrificed for biochemical and histological analyses. The remaining rats were mated with males of proven fertility for 5 days. The daily examination of vaginal smears allowed the evaluation of fertility index. After parturition, additional fertility parameters were determined. Results showed that in PCOS rats, AE decreased body weight (p < 0.001), abdominal fat weight (p < 0.001), serum levels of LH (p < 0.001), testosterone (p < 0.001), total cholesterol (p < 0.05), and LDL cholesterol (p < 0.01). HDL cholesterol increased and atherogenic indices decreased (p < 0.001). The number of Graafian follicles and corpora lutea increased, while cystic (p < 0.001) and atretic (p < 0.05) follicles decreased. AE also decreased oxidative stress in the ovaries, restored the estrous cycle, induced uterine epithelial cell hypertrophy, and improved fertility. These effects were attributed to phenols, flavonoids, terpenoids, and anthocyanins present in AE. The overall results justify the traditional use of A. ampeloprasum against female infertility and suggest its potential use as a dietary supplement for PCOS patients.

Alpinumisoflavone Activates Disruption of Calcium Homeostasis, Mitochondria and Autophagosome to Suppress Development of Endometriosis

Alpinumisoflavone is an isoflavonoid extracted from the Cudrania tricuspidate fruit and Genista pichisermolliana. It has various physiological functions, such as anti-inflammation, anti-proliferation, and apoptosis, in malignant tumors. However, the effect of alpinumisoflavone is still not known in chronic diseases and other benign reproductive diseases, such as endometriosis. In this study, we examined the cell death effects of alpinumisoflavone on the endometriosis cell lines, End1/E6E7 and VK2/E6E7. Results indicated that alpinumisoflavone inhibited cell migration and proliferation and led to cell cycle arrest, depolarization of mitochondria membrane potential, apoptosis, and disruption of calcium homeostasis in the endometriosis cell lines. However, the cellular proliferation of normal uterine epithelial cells was not changed by alpinumisoflavone. The alteration in Ca²⁺ levels was estimated in fluo-4 AM-stained End1/E6E7 and VK2/E6E7 cells after alpinumisoflavone treatment with or without calcium inhibitor, 2-aminoethoxydiphenyl borate (2-APB). The results indicated that a combination of alpinumisoflavone and a calcium inhibitor reduced the calcium accumulation in the cytosol of endometriosis cells. Additionally, alpinumisoflavone decreased oxidative phosphorylation (OXPHOS) in the endometriotic cells. Moreover, protein expression analysis revealed that alpinumisoflavone inactivated AKT signaling pathways, whereas it increased MAPK, ER stress, and autophagy regulatory proteins in End1/E6E7 and VK2/E6E7 cell lines. In summary, our results suggested that alpinumisoflavone could be a promising effective management agent or an adjuvant therapy for benign disease endometriosis.

Estrogenic and anti-amnesic potential of Millettia griffoniana Baill. (Fabaceae) ethanolic extract on scopolamine-induced memory impairment in ovariectomized Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Dementias including Alzheimer disease (AD) are three times higher in menopausal women than in men. Phytoestrogens, a group of plant-derived compounds are known to alleviate menopausal complaints including dementia. Millettia griffoniana Baill is a phytoestrogen-rich plant used to treat menopausal complaints and dementia.

AIM

Evaluating the estrogenic and neuroprotective potential of Millettia griffoniana on ovariectomized (OVX) rats.

MATERIALS AND METHODS

The in vitro safety of M. griffoniana ethanolic extract was assayed by MTT in human mammary epithelial (HMEC) and mouse neuronal (HT-22) cells and its lethal dose 50 (LD₅₀) was estimated following OECD 423 guidelines. For estrogenicity, in vitro the well known E-screen assay on MCF-7 cells was performed and in vivo four groups of OVX rats were treated either with 75, 150 and 300 mg/kg M. griffoniana extract doses or estradiol (1 mg/kg BW) for three days; and changes in uterine and vagina were analyzed. Then, for neuroprotective effect, Alzheimer-type dementia induction was achieved by scopolamine (1.5 mg/kg B.W., i.p.) injection four days/week and M. griffoniana extract as well as piracetam (standard) were administered daily for 2 weeks to evaluate the extract's neuroprotective potential. The endpoints were the assessment of learning and working memory, oxidative stress state (SOD, CAT, and MDA) in brain, acetylcholine esterase (AChE) activity and the histopathological changes in hippocampus.

RESULTS

No toxic effect was observed when incubating mammary (HMEC) and neuronal (HT-22) cells with M. griffoniana ethanol extract for 24 h and its LD₅₀ was found >2000 mg/kg. The extract also exhibited both in vitro and in vivo estrogenic activities, displayed by a significant (p < 0.01) increment in MCF-7 cells population in vitro and an increase in the epithelium height of the vagina and the wet weight of the uterus mainly with the 150 mg/kg BW extract dose compared to untreated OVX rats. The extract also reversed scopolamine-induced memory impairment in rat by improving learning, working and reference memory. This was associated with an increment in CAT and SOD expression, alongside a decrement in MDA content and AChE activity in hippocampus. Further, the extract reduced neuronal cell loss in hippocampal structures (CA1, CA3 and dentate gyrus). High Performance Liquid Chromatography coupled with Mass Spectrometry (HPLC-MS) spectra, revealed the presence of numerous phytoestrogens in M. griffoniana extract.

CONCLUSION

M. griffoniana ethanolic extract has estrogenic, anticholinesterase and antioxidant activities that could account for its anti-amnesic effects. These findings therefore sheds light on why this plant is commonly used in the therapy of menopausal complaints and dementia.

The Genus Eriosema (Fabaceae): From the Ethnopharmacology to an Evidence-Based Phytotherapeutic Perspective?

The genus Eriosema (Fabaceae) includes approximately 150 species widely distributed across tropical and subtropical regions of the world (Africa, Neotropics, Asia and Australia). Throughout these regions, several species are used since centuries in different traditional medicinal systems, while others are used as food or food supplement. The present review attempts to critically summarize current information concerning the uses, phytochemistry and pharmacology of the Eriosema genus and to evaluate the therapeutic potential. The information published in English and French (up to September 2020) on ethnopharmacology or traditional uses, chemistry, pharmacology and toxicology of Eriosema genus was collected from electronic databases [SciFinder, PubMed, Google, Google Scholar, Scopus, Web of Science, Prelude Medicinal Plants—http://www.ethnopharmacologia.org/recherche-dans-prelude/?plant, The Plant List (http://www.theplantlist.org/), POWO (http://powo.science.kew.org/) and IUCN Red List Categories (https://www.iucnredlist.org/)], conference proceedings, books, M.Sc. and Ph.D. dissertations. The information retrieved on the ethnomedicinal indications of Eriosema genus allowed to list 25 species (∼16.6% of the genus). The majority of uses is recorded from Africa. Phytochemical analyses of 8 species led to the identification and/or isolation of 107 compounds, with flavonoids (69.2%), chromones (7.5%) and benzoic acid derivatives (3.7%) as the main chemical classes. Pharmacological investigations with crude extracts and isolated compounds showed a broad range of activities including aphrodisiac, estrogenic, anti-osteoporosis, hypolipidemic, anti-diabetic, anti-diarrheal, anti-microbial, anti-oxidant, anthelmintic, anti-cancer, and acetylcholinesterase inhibitory activities. Despite the low number of Eriosema species tested, there is convincing evidence in vitro and in vivo studies validating some traditional and ethnobotanical uses. However, the utility of several of the described uses has not yet been confirmed in pharmacological studies. Reviewed data could serve as a reference tool and preliminary information for advanced research on Eriosema species.

Regular consumption of "Nkui", a Cameroonian traditional dish, may protect against cardiovascular and bone disorders in an estrogen deficiency condition

OBJECTIVES

There is a growing body of evidence indicating the potential of culinary herbs and spices to decrease the incidence of several chronic diseases or conditions. Because of this, the WHO recommends their regular consumption. In the Cameroonian culinary practices, "Nkui" is a famous dish made from a mixture of 10 spices. In our previous study, the ethanolic extract of this mixture exhibited promising estrogenic properties. Thus, this study aimed to evaluate its protective effects on some menopause-related cardiovascular and bone disorders.

METHODS

For this purpose, a post-menopause-like model (ovariectomized rats) has been used. Animals were orally treated with the "Nkui" extract for 60 days. The investigation focused on the oxidative stress status, endothelial function (NO bioavailability), lipid profile, and bone mass, biochemical (calcium and inorganic phosphorus contents, serum alkaline phosphatase activity) and histomorphological features.

RESULTS

The extract regulated lipid metabolism in a way to prevent accumulation of abdominal fat, gain in body weight and increased atherogenic indexes induced by ovariectomy. It prevented menopause-related low levels of nitric oxide and oxidative stress damage by increasing superoxide dismutase and catalase activities, while reducing glutathione and malondialdehyde levels in the heart and aorta. Moreover, it prevented ovariectomy-induced bone mass loss, bone marrow disparities and the disorganization of the trabecular network. It also increased femur calcium and inorganic phosphorus contents.

CONCLUSIONS

These results suggest that a regular consumption of "Nkui" may have health benefits on cardiovascular system and osteoporosis, major health issues associated with menopause.

The Aqueous Extract of Dacryodes edulis (Burseraceae) Leaves Inhibits Cell Proliferation Induced by Estradiol on the Uterus and Vagina of Ovariectomized Female Wistar Rats

Proliferation is a cellular process strongly linked to the genesis of cancer. Natural substances with antiproliferative activities are currently potential alternatives in the treatment of cancers. Dacryodes edulis, for instance, is a medicinal plant traditionally used in the treatment of cancer. Scientific studies have reported the antioxidant activity of this plant. In addition, the presence of prostate cancer chemopreventive polyphenols was reported in D. edulis extracts. Therefore, this study was aimed to evaluate the effects of the aqueous extract of D. edulis leaves on cell proliferation induced by estradiol in ovariectomized female Wistar rats. In this regard, ovariectomized (OVX) rats were cotreated with estradiol valerate (E₂V) (0.75 mg/kg) and the aqueous extract of D. edulis leaves. Control groups received either the vehicle (sham-operated animals and the OVX control), E₂V (0.75 mg/kg) only, or E₂V (0.75 mg/kg) and tamoxifen (10 mg/kg). Treatments were administered orally for 3 consecutive days, and animals were sacrificed thereafter. Epithelial heights of the uterus and vagina were assessed. Uterine levels of total cholesterol and estradiol were determined as well. Results showed that the aqueous extract of D. edulis leaves reversed the effects of estradiol as it reduced uterine weight (p < 0.05), uterine (p < 0.05), and vaginal (p < 0.001) epithelium heights. This antiproliferative effect of D. edulis was associated with reduced tissue (uterine) levels of estradiol (p < 0.001). These results suggest that the aqueous extract of D. edulis leaves could be a potential alternative treatment for proliferation-related diseases.

Salvia officinalis mitigates uterus and liver damages induced by an estrogen deficiency in ovariectomized rats

The present study evaluated the antioxidant activity of Salvia officinalis (sage) and its protective effect on estrogen deficiency in ovariectomized rats. Female Wistar rats were treated during either 15 or 30 days as follows: group C: negative controls, group S: positive controls treated with sage leaves, ovariectomized rats (group OVX) and ovariectomized rats receiving either sage (OVX-S) or hormonal (Group OVX-E) treatments, respectively. After 15 and 30 days of treatments, OVX rats showed a gain in body weight and an increase of absolute and relative liver weights. Meanwhile, absolute and relative uterus weights were decreased. Moreover, ovariectomy altered plasma transaminases' activities, lipid profile, and disrupted the redox status of liver and uterine tissues. It affected also the reproductive tract by decreasing the uterus glycogen content and plasma LDH activity. Supplementation of sage via the diet reduced weight gain and oxidative stress resulting from estrogen deficiency. PRACTICAL APPLICATIONS: During menopause, sexual hormone deficiency, especially estrogen, causes several morphological and physiological disturbances in liver and uterus tissues. In fact, the body weight gain and disturbances of redox status in liver and uterus were the main health problems detected after menopause. Sage leaves, used as medicinal plant, exerted its beneficial effects in the management of menopause disorders. As an important source of antioxidants, sage leaves could prevent obesity and oxidative damage in the liver and uterus resulting from estrogen deficiency.

A Pharmacological Overview of Alpinumisoflavone, a Natural Prenylated Isoflavonoid

Over the last decade, several studies demonstrated that prenylation of flavonoids enhances various biological activities as compared to the respective nonprenylated compounds. In line with this, the natural prenylated isoflavonoid alpinumisoflavone (AIF) has been explored for a number of biological and pharmacological effects (therapeutic potential). In this review, we summarize the current information on health-promoting properties of AIF. Reported data evidenced that AIF has a multitherapeutic potential with antiosteoporotic, antioxidant and anti-inflammatory, antimicrobial, anticancer, estrogenic and antiestrogenic, antidiabetic, and neuroprotective properties. However, research on these aspects of AIF is not sufficient and needs to be reevaluated using more appropriate methods and methodology. Further series of studies are needed to confirm these pharmacological effects, and this review should lay the basis for the design of respective investigations. Overall, despite the drawbacks of studies recorded, AIF exhibits a potential as drug candidate.

Lannea acida A. Rich. (Anacardiaceae) Ethanol Extract Exhibits Estrogenic Effects and Prevents Bone Loss in an Ovariectomized Rat Model of Osteoporosis

Phytoestrogens have been shown to prevent postmenopausal osteoporosis. Lannea acida is a medicinal plant traditionally used in Cameroon to treat infertility, gynaecological complaints, and rheumatism. These uses prompted us to evaluate estrogenic activity of Lannea acida bark ethanolic extract and its antiosteoporotic potential in ovariectomized Wistar rats. In vitro, the E-screen assay was used to assess the ability of L. acida extract to induce MCF-7 cells proliferation. In vivo, a 3-day uterotrophic assay and a 12-week oral treatment in ovariectomized adult rats were carried out to evaluate the ability of L. acida extract to prevent bone mass loss. L. acida extract induced MCF-7 cell proliferation. In vivo, it significantly increased the uterine wet weight, uterine and vaginal epithelial heights, and mammary glands differentiation. At 200 mg/kg, a long-term treatment with the extract prevented body weight gain (p < 0.05) and loss of bone mass and/or density (p < 0.05) induced by ovariectomy. Also, a significant (p < 0.001) decrease of alkaline phosphatase activity was observed with 50 mg/kg. L. acida extract improved bone microarchitecture and could restore normal bone mineralization by increasing the inorganic phosphorus and calcium level in bone. These findings provide evidence that Lannea acida is a potential alternative for the prevention of postmenopausal osteoporosis.

Activity based evaluation of a traditional Ayurvedic medicinal plant: Saraca asoca (Roxb.) de Wilde flowers as estrogenic agents using ovariectomized rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Saraca asoca (Roxb.) de Wilde, Ashok, is a popular traditional plant used for gynecological disorders. In India, the juice of Ashok flowers is traditionally consumed as a tonic by women in case of uterine disorders. But despite the use, its estrogenic potency is not yet evaluated and thus lacks the scientific recognition and acclaim.

AIM OF THE STUDY

This study is designed to investigate the estrogenic potential of standardized ethanolic extract of Saraca asoca flowers (SAF) using ovariectomized (OVX) female albino Wistar rat model.

MATERIALS AND METHODS

Saraca asoca flowers were extracted in ethanol using hot maceration technique and the extract was standardized in terms of content of four phytoestrogens like quercetin, kaempferol, β-sitosterol and luteolin using HPTLC technique. Safety of the extract was evaluated at a dose of 2000mg/kg body weight in female albino Wistar rats as per the OECD guidelines. Bilateral ovariectomy surgery was performed for the excision of both the ovaries. The OVX animals were treated with the ethanolic extract of SAF at three dose levels- 100mg/kg, 200mg/kg and 400mg/kg body weight in distilled water as a vehicle, orally once a day for two weeks. Estradiol valerate was employed as a modern drug for comparative evaluation of the results. Estrogenic potency was studied by assaying the activities of serum and plasma marker enzymes and hormones viz. G6PDH, LDH, 17β-estradiol, progesterone along with cholesterol, triglycerides and HDL, and vaginal cornification. The uterotrophic effect was evaluated by studying the histoarchitecture of the uterus, effect on uterine weight and changes in the levels of uterine glycogen content.

RESULTS

HPTLC revealed the presence of markers like quercetin, kaempferol, β-sitosterol and luteolin from the ethanolic extract of SAF. The content of the four markers was found to be 1.543mg/g, 0.924mg/g, 4.481mg/g and 2.349mg/g, respectively. SAF extract was found to be safe at an oral dose of 2000mg/kg body weight in rats. Among the three doses administered to ovariectomized rats, treatment with high dose was found to be more efficacious when compared with ovariectomized rats.

CONCLUSION

The findings of this study firmly support the estrogenic potency of ethanolic extract of SAF which may be by the reason of phytoestrogens.

Safety evaluation (acute and sub-acute studies) of the aqueous extract of the leaves of Myrianthus arboreus P. Beauv. (Cecropiaceae) in Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Myrianthus arboreus P. Beauv (Cecropiaceae) is a medicinal plant distributed in forests and damp places of tropical Africa. Its leaves are widely used as food and/or for the treatment of various ailments including dysmenorrhoea, female infertility, tumors and diarrhea. However, to the best of our knowledge, no safety assessment of this plant has been reported yet.

AIM OF STUDY

The present study aimed at evaluating the safety of the aqueous extract of leaves of Myrianthus arboreus (MAA) in Wistar rats through an acute and sub-acute oral administration.

MATERIAL AND METHODS

In acute oral toxicity, the test was performed according to the Organization for Economic Cooperation and Development (OECD) guidelines Nr. 423 (acute toxicity class method, ATC) with slight modifications. Female Wistar rats were orally treated with the aqueous extract of M. arboreus at the doses of 2000 and 5000mg/kg. In sub-acute toxicity study, using the OECD guidelines Nr. 407, the extract was administered by gavage at the doses of 20, 110 and 200mg/kg/day for 28 consecutive days.

RESULTS

A single oral administration of 2000 or 5000mg/kg of the extract induced neither mortality nor exterior signs of toxicity indicating a LD₅₀ >5000mg/kg. In sub-acute study, the extract decreased triglycerides, total cholesterol/high density lipoproteins ratio and atherogenic index of plasma in both sexes at all tested doses. Alanine transaminase decreased in both sexes at 200mg/kg and serum creatinine levels decreased at all tested doses in females. Moreover, significant increases in ovarian and uterine wet weights, red blood cell count, hematocrit, mean corpuscular hemoglobin and hemoglobin were observed at 200mg/kg in females. In males, this extract decreased white blood cell count, lymphocytes and relative weight of seminal vesicles and ventral prostate at 200mg/kg.

CONCLUSION

The aqueous extract of Myrianthus arboreus leaves was non-toxic in acute administration and exhibited a relatively low toxicity potential on accessory sex organs in both sexes, and leukocytes in males following the repeated 28-days oral administration of the dose 200mg/kg.

In vivo estrogenic-like activities of Gouania longipetala Hemsl. (Rhamnaceae) bark extracts in a post-menopause-like model of ovariectomized Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Gouania longipetala is commonly used in Cameroonian traditional medicine to manage women fertility and menopausal complaints. However, despite this use, the estrogenic properties of G. longipetala have not been studied until now.

AIM OF STUDY

The present study was aimed to assess estrogenic activities of the stem bark aqueous (GLA) and ethanolic (GLE) extracts of G. longipetala in post-menopause-like model of ovariectomized (Ovx) Wistar rats.

MATERIAL AND METHODS

Animals were either sham-operated or Ovx. 84 days after ovariectomy, animals were divided into seven groups of five animals and were daily treated for 28 days with distilled water (10 mL/kg) for group 1, 2% solution of Tween 80 (10 mL/kg) for group 2, estradiol valerate (1 mg/kg) for group 3, GLA (45 or 180 mg/kg) and GLE (40 or 160 mg/kg) for groups 4 to 7 respectively. Sham-operated animals daily received distilled water (10 mL/kg). During the experimental period, the body weight was registered every week. At the day 29, blood pressure was registered by invasive method while uterine and vagina morphometry as well as body, uterine and abdominal fat weights changes were analyzed. Serum levels of total cholesterol, triglycerides, HDL-cholesterol and LDL-cholesterol were determined. Moreover, oxidative stress markers such as nitrites, reduced glutathione (GSH) and malondialdehyde (MDA) were measured in homogenized liver and aorta.

RESULTS

Compared with the sham control, vagina and uterine dystrophy and elevated blood pressure were observed in Ovx rats treated with vehicles. Biochemical parameters showed a significant increase of total cholesterol, triglycerides, LDL-cholesterol and MDA as well as a significant decrease of nitrites and GSH in Ovx animals treated with vehicle as compared to sham group. GLA and GLE displayed estrogen-like effects on vagina and did not affect uterine wet weight and epithelial height compared with vehicle groups. Both extracts displayed anti-atherogenic properties by reducing AI, AIP and LDL-cholesterol level as compared to vehicles groups. GLA and GLE significantly prevented the increase of MDA induced by ovariectomy as compared to rats treated with vehicles.

CONCLUSION

This study showed that GLA and GLE exhibited estrogenic effects by providing vaginal lubrication, by modulating blood pressure and improving lipid profile, oxidative status and endothelial function and may not have an undesirable influence on the endometrium in ovariectomized rats.

Alpinumisoflavone and abyssinone V 4'-methylether derived from Erythrina lysistemon (Fabaceae) promote HDL-cholesterol synthesis and prevent cholesterol gallstone formation in ovariectomized rats

OBJECTIVES

Erythrina lysistemon was found to improve lipid profile in ovariectomized rats. Alpinumisoflavone (AIF) and abyssinone V 4'-methylether (AME) derived from this plant induced analogous effects on lipid profile and decreased atherogenic risks. To highlight the molecular mechanism of action of these natural products, we evaluated their effects on the expression of some estrogen-sensitive genes associated with cholesterol synthesis (Esr1 and Apoa1) and cholesterol clearance (Ldlr, Scarb1 and Cyp7a1).

METHODS

Ovariectomized rats were subcutaneously treated for three consecutive days with either compound at the daily dose of 0.1, 1 and 10 mg/kg body weight (BW). Animals were sacrificed thereafter and their liver was collected. The mRNA of genes of interest was analysed by quantitative real-time polymerase chain reaction.

KEY FINDINGS

Both compounds downregulated the mRNA expression of Esr1, a gene associated with cholesterogenesis and cholesterol gallstone formation. AME leaned the Apoa1/Scarb1 balance in favour of Apoa1, an effect promoting high-density lipoprotein (HDL)-cholesterol formation. It also upregulated the mRNA expression of Ldlr at 1 mg/kg/BW per day (25%) and 10 mg/kg/BW per day (133.17%), an effect favouring the clearance of low-density lipoprotein (LDL)-cholesterol. Both compounds may also promote the conversion of cholesterol into bile acids as they upregulated Cyp7a1 mRNA expression.

CONCLUSION

AIF and AME atheroprotective effects may result from their ability to upregulate mechanisms promoting HDL-cholesterol and bile acid formation.

Erythrina lysistemon-derived flavonoids account only in part for the plant's specific effects on rat uterus and vagina

BACKGROUND

The stem bark ethyl acetate extract of Erythrina lysistemon was found to induce vaginal proliferation in ovariectomized rats orally treated. Alpinumisoflavone (AIF) and abyssinone V-4'-methyl-ether (AME), isolated as its major constituents, were reported to separately provoke uterine growth and/or vaginal proliferation. The present study aimed at evaluating the effects of the mixture of AIF and AME (51 mg/kg [AIF]+153 mg/kg [AME]) following their relative abundance in the extract, in order to compare these effects to those of E. lysistemon.

METHODS

The study was performed in ovariectomized rats treated intraperitoneally for 3 days. Estradiol valerate (E2 V) and AME were used for positive controls. Morphological and histological changes of animals' uterus and vagina were used as the hallmark of estrogenicity.

RESULTS

E. lysistemon extract induced estrogen-like effects only on the uterus and significantly increased uterine wet weight (p<0.01) and uterine epithelial height (p<0.01). These results suggest a tissue-selective action of E. lysistemon extract depending on the route of administration. The mixture of AIF and AME induced E. lysistemon-like effects only at a dose of 1 mg/kg BW/d (0.25 mg/kg+0.75 mg/kg), although these effects were lower in magnitude (p<0.05) compared to those induced by E. lysistemon extract.

CONCLUSIONS

Effects induced by the mixture of AIF and AME are analogous to those of E. lysistemon, but the low magnitude of these effects suggests that there are minor metabolites that interact with AIF and AME to provoke the specific effects of E. lysistemon.

Eriosema laurentii De Wild (Leguminosae) methanol extract has estrogenic properties and prevents menopausal symptoms in ovariectomized Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Eriosema laurentii De Wild (Leguminosae) is a medicinal plant used in West and Central Africa for different diseases. In Cameroon, this plant is used as a treatment for infertility, and various gynecological and menopausal complaints. However, despite this use as a natural remedy, the biological activity of Eriosema laurentii has not been studied until now.

AIM OF STUDY

In order to determine the potential use of this plant in gynecological conditions/disorders, we evaluated the estrogenic properties of a methanol extract of its aerial parts and its ability to prevent different menopausal health problems induced by bilateral oophorectomy.

MATERIAL AND METHODS

Two approaches were used. In vitro, recombinant yeast systems were applied, featuring either the respective human receptors (ERα, AR, and PR) or into chromosome III integrated human aryl hydrocarbon receptor (AhR) and the respective reporter plasmid. In vivo, the investigation was carried out using the 3 days uterotrophic assay and 9 weeks oral treatment in ovariectomized rats.

RESULTS

The results showed that the methanol extract of the aerial parts of Eriosema laurentii transactivated the estrogen receptor-α and displayed AhR agonistic activity but was neither androgenic nor progesteronic. In rats, the extract did not induce endometrium proliferation either in the 3-day or the 9-week treatment regimens, but induced vaginal stratification and cornification, prevented loss of femur bone mass, increased high density lipoprotein cholesterol (HDL-C), and reduced total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), TC/HDL-C ratio, LDL-C/HDL-C ratio and the atherogenic index of plasma (AIP).

CONCLUSION

These results suggest that the methanol extract of the aerial parts of Eriosema laurentii does not seem to have an undesirable influence on the endometrium but might prevent vaginal dryness and bone mass loss and improve the lipid profile.