Effects of visnagin on cyclic nucleotide phosphodiesterases and their role in its inhibitory effects on vascular smooth muscle contraction

Efficacy and safety of visnadine in the treatment of symptoms of sexual dysfunction in heterosexual women: a systematic review of randomized clinical trials

OBJECTIVE

To synthesize the primary evidence on the efficacy and safety of visnadine on symptoms of sexual dysfunction (SD) in heterosexual women.

METHODS

We conducted a systematic review of randomized clinical trials (RCTs) with a primary search without language restriction in PubMed/Medline, Scopus, Embase, Web of Science, Cochrane Library, and international clinical trial registries. Trials reporting the use of visnadine by any route in women with SD were eligible. We performed screening, data extraction, and risk of bias assessment in a double-blind approach. The primary outcomes were the Female Sexual Function Index (FSFI) and its domains. Secondary outcomes were safety, arousal, lubrication, pleasure, orgasm, negative sensations, duration, and overall satisfaction.

RESULTS

Initially, 242 records were retrieved. We selected nine papers for full-text reading and finally included two RCTs: one with a parallel design and one with a crossover design with a total of 96 patients. One study compared visnadine aerosol with a placebo, while the other compared different frequencies of visnadine aerosol use. Visnadine use showed a statistically significant improvement (p < 0.05) in overall FSFI scores, regardless of the frequency of use. A meta-analysis was not possible due to the high clinical and methodological heterogeneity between available studies.

CONCLUSION

RCTs regarding the use of visnadine for the Female SD are scarce and methodologically limited. This preliminary evidence shows visnadine as a potentially effective and safe option to alleviate some of the clinical symptoms of SD in heterosexual women. However, future better-designed randomized studies with larger sample numbers are required.

Therapeutic potential and pharmacological mechanism of visnagin

Visnagin is a furanochromone and one of the most important compound in the Ammi visnaga (L.) Lam (a synonym of Visnaga daucoides Gaertn.) plant, which is used to cure various ailments. Many investigations into the bioactive properties of visnagin have been studied to date. The literature on visnagin demonstrates its biological properties, including anti-inflammatory, anti-diabetic, and beneficial effects in cardiovascular and renal diseases. Moreover, visnagin improves sperm quality parameters, stimulates steroidogenesis, and increases serum gonadotropins and testosterone levels, while decreasing pro-inflammatory cytokines, oxidative damage, genomic instability, and it modulates apoptosis. Thus, visnagin has emerged as an exciting lead for further research, owing to its potential in various unmet clinical needs. The current review summarized its basic structure, pharmacokinetics, and pharmacological effects, focusing on its mechanisms of action. The review will help to understand the potential of visnagin as an alternative treatment strategy for several diseases and provide insight into research topics that need further exploration for visnagin's safe clinical use. Please cite this article as: Yadav P, Singh SK, Datta S, Verma S, Verma A, Rakshit A, Bali A, Bhatti JS, Khurana A, Navik U. Therapeutic potential and pharmacological mechanism of visnagin. J Integr Med. 2024; 22(4): 399-412.

Synthesis, Herbicidal Activity, and Structure-Activity Relationships of O-Alkyl Analogues of Khellin and Visnagin

Khellin and visnagin furanochromones were recently reported as potential new bioherbicides with phytotoxic activities comparable to those of some commercially available herbicides. In this study, we examined the effect of O-alkylation and O-arylalkylation of both khellin and visnagin on its effect on herbicidal and antifungal activity. Synthetic analogues included O-demethyl khellin and visnagin, acetylated O-demethyl khellin and visnagin, O-benzylated demethyl khellin and visnagin, four O-demethyl alkylated khellin analogues, and six O-demethyl alkylated visnagin analogues, many of which are reported here for the first time. Both acetate analogues of khellin and visnagin indicated more activity as herbicides on Lemna pausicostata than visnagin, with IC50 values of 71.7 and 77.6 μM, respectively. Complete loss of activity for all O-alkyl analogues with a carbon chain length of greater than 14 carbons was observed. The O-demethyl butylated visnagin analogue was the most active compound with an IC50 of 47.2 μM against L. pausicostata. O-Demethyl ethylated analogues of both khellin and visnagin were as effective as khellin. In the antifungal bioautography bioassay against Colletotrichum fragariae at 100 μg, the only active O-alkyl and O-arylalkyl analogues were O-ethylated, O-butylated, and O-benzylated visnagin analogues with zones of inhibition of 10, 9, and 9 mm, respectively, an effect comparable to that of visnagin and khellin.

Medicinal plants as a potential source of Phosphodiesterase-5 inhibitors: A review

ETHNOPHARMACOLOGICAL RELEVANCE

The prevalence and distress caused by erectile dysfunction (ED) to both male and female partners are increasing at a steady rate. ED has now become the most treated sexual disorder for men among young and old age groups due to varying physical and psychological factors. The treatment with synthetic Phosphodiesterase-5 (PDE5) inhibitors are cost-effective but due to adverse effects such as priapism, loss of vision, heart attack and syncope, the daily life patterns of these patients are distressed and hence the need for alternative medicaments or sources are of utmost important. Therefore, the exploration of medicinal plants as PDE5 inhibitors will be worthwhile in tackling the problems as many plant extracts and fractions have been long used as aphrodisiacs and sexual stimulants which may be found to be active against PDE5 enzyme.

AIM OF THE STUDY

To provide a review on the different medicinal herbs traditionally used as natural aphrodisiacs, libido or sexual enhancers which are proven for their PDE5 inhibitory effect.

MATERIALS AND METHODS

Ethnobotanical and scientific information was procured, reviewed and compiled from the literature search of electronic databases and search engines.

RESULTS

A total of 97 medicinal plants exhibiting PDE5 inhibitory effect are reviewed in this paper which is supported by preclinical experimental evidence. Among them, 77 plants have been selected according to their traditional and ethnobotanical uses as aphrodisiacs and the rest are screened according to their effectiveness against predisposing factors responsible for ED and sexual dysfunction such as diabetes and hypertension or due to the presence of phytochemicals having structural similarity towards the identified natural PDE5 inhibitors. In addition, sixteen alkaloids, sixty-one phenolics and eight polycyclic aromatic hydrocarbons have been isolated or identified from active extracts or fractions that are exhibiting PDE5 inhibitory activity. Among them, isoflavones and biflavones are the major active constituents responsible for action, where the presence of prenyl group for isoflavones; and the methoxy group at C-5 position of flavones are considered essential for the inhibitory effect. However, the prenylated flavonol glycoside, Icariin and Icariside II isolated from Epimedium brevicornum Maxim (hory goat weed) are the most effective inhibitor, till date from natural sources. Traditional medicines or formulations containing extracts of Ginkgo biloba L., Kaempferia parviflora Wall. ex Baker, Clerodendrum colebrookianum Walp., Eurycoma longifolia Jack and Vitis vinifera L. are also found to be inhibitors of PDE5 enzyme.

CONCLUSION

The review suggests and supports the rational use of traditional medicines that can be further studied for the development of potential PDE5 inhibitors. Many traditional medicines are still used in various regions of Africa, Asia and South America that are poorly characterized and experimented. Despite the availability of a vast majority of traditional formulations as aphrodisiacs or sexual stimulants, there exists a need for systemic evaluation on the efficacy as well as the mechanism of action of the herbal constituents for the identification of novel chemical moieties that can be further developed for maximum efficacy.

Visnagin ameliorates myocardial ischemia/reperfusion injury through the promotion of autophagy and the inhibition of apoptosis

Visnagin is a furanochromone and one of the main compounds of Ammi visnaga L. that had been used to treat nephrolithiasis in Ancient Egypt. Nowadays, visnagin was widely used to treat angina pectoris, urolithiasis and hypertriglyceridemia. The potential mechanisms of visnagin involved in inflammation and cardiovascular disease were also identified. But the protective effect of visnagin on myocardial ischemia/reperfusion injury has not been confirmed. Our aim was, for the first time, to investigate the potential protective effect of visnagin on cardiac function after myocardial ischemia-reperfusion injury in a rat model, and to identify its underlying mechanism involving the inhibition of apoptosis and induction of autophagy. Thirty SD rats were randomly divided into sham group, ischemia/reperfusion group (IR), ischemia/reperfusion with visnagin (IR + visnagin) group. Myocardial ischemia/Reperfusion injury model was established. Hemodynamic measurements and echocardiography were used to analyze cardiac function, TUNEL staining and caspase activity, LC3 dots were detected with immunofluorescence staining, LC3 expression was evaluated by western blot analysis, transmission electron microscopy (TEM) was used to detect autophagosomes. Compared with the sham group and visnagin group, the cardiac dysfunction, LC3II, autophagy flow in the IR+ visnagin group increased significantly (P<0.01), but the activity of caspase-3 and caspase-9 and the apoptotic in the IR + visnagin group decreased significantly (P<0.01). In conclusion, visnagin may play a protective role in ischemia/reperfusion injury by inducing autophagy and reducing apoptosis.

Ammi Visnaga L., a Potential Medicinal Plant: A Review

Ammi visnaga L. (Visnaga daucoides Gaertn., Family Apiaceae), also known as Khella Baldi or toothpick weed, is an annual or biennial herb indigenous to the Mediterranean region of North Africa, Asia, and Europe. The plant is known to have been used in traditional medicine a long time ago. Nowadays, it is used in modern medicine to treat many aliments such as renal colic and coronary insufficiency, and is used as an antioxidant, antifungal, and antibacterial, with a larvicidal effect on mosquito larvae. Peer-reviewed studies show that these pharmacological activities are due its valuable chemical constituents that include mainly essential oil, polyphenolic compounds including flavonoids, as well as γ-pyrones, represented mainly by khellin and visnagin. Its essential oil is reported to have antiviral, antibacterial, and larvicidal effects, while its flavonoid content is responsible for its antioxidant activity. Its γ-pyrone content has a powerful effect on facilitating the passage of kidney stones and relieving renal colic, in addition to having a relaxant effect on smooth muscle including that of the coronary arteries. The current review represents the progress in research on A. visnaga in terms of either its chemistry or biological activities. This review represents scientific support material for the use of the plant by the pharmaceutical industry.

Visnagin attenuates acute pancreatitis via Nrf2/NFκB pathway and abrogates associated multiple organ dysfunction

Acute pancreatitis (AP) is an exocrine dysfunction of the pancreas where oxidative stress and inflammatory cytokines play a key role in induction and progression of the disease. Studies have demonstrated that antioxidant phytochemicals have been effective in improving pancreatitis condition, but there are no clinically approved drugs till date. Our study aims to assess the preventive activity of visnagin, a novel phytochemical isolated from Ammi visnaga against cerulein induced AP. Male Swiss albino mice were divided into six groups (n = 6, each group) comprising of normal control, cerulein control, seven day pre-treatment with visnagin at three dose levels; visnagin low dose (10 mg/kg), visnagin mid dose (30 mg/kg), visnagin high dose (60 mg/kg) and visnagin control (60 mg/kg). AP was induced by six injections of cerulein (50 μg/kg, i.p.) on the 7^th day and the animals were sacrificed after 6 h of last cerulein dose. Various markers of pancreatic function, oxidative stress and inflammation were assessed. Visnagin was found to be effective in reducing plasma amylase and lipase levels, reduced cerulein induced oxidative stress. Visnagin dose dependently decreased the expression of IL-1β, IL-6, TNF-α and IL-17. It attenuated the levels of nuclear p65-NFκB. Visnagin improved the antioxidant defence by improving Nrf2 expression and halted pancreatic inflammation by suppressing NFκB and nitrotyrosine expression in the acinar cells. Further, it attenuated the expression of markers of multiple organ dysfunction syndrome and reduced inflammatory cytokines in lungs and intestine. Cumulatively, these findings indicate that visnagin has substantial potential to prevent cerulein induced AP.

Is the use of plants in Jordanian folk medicine for the treatment of male sexual dysfunction scientifically based? Review of in vitro and in vivo human and animal studies

Male sexual dysfunction is a serious problem which has an impact on the quality of life. In Jordanian folk medicine, 56 plant species were reported to be used by males to improve sexual potency and as aphrodisiacs. The aim of this study was to search for scientific evidence justifying their folk use. Of the 15 studied plants, only five were found to enhance spermatogenesis. The other 10 were reported to decrease spermatogenesis at least by one study. The majority of the studied plants possessed a protective effect on testis in different in vivo models as well as antioxidant activities. The effect of these plants on steroidogenesis and the hypothalamic-gonadal axis was also reviewed. The effect of only five plants was studied on sexual behaviour enhancement and three of them were active. Three of the four studied plants enhanced erection. The mechanism of action of active constituents isolated from the studied plants was also investigated. In conclusion, many plants used in Jordanian folk medicine decreased or had no effect on spermatogenesis in animal models. These plants have antioxidant and/or adaptogenic effects, and this may result in a beneficial action on male reproductive system.

DNA binding, antiviral activities and cytotoxicity of new furochromone and benzofuran derivatives

Bromination of visnagin (1) afforded 9-bromovisnagin (2) which on its alkaline hydrolysis afforded the 3-acetyl benzofuran derivative (3). The condensation of (3) with hydrazine hydrate, phenylhydrazine and/or hydroxylamine hydrochloride afforded the corresponding pyrazole derivatives (4a, b) and isoxazole derivative (4c). On the other hand, when compound 3 was condensed with some aromatic aldehydes, this yielded corresponding α, β-unsaturated keto derivatives (5a-e). Furthermore, when 1 was subjected to chlorosulfonation, the visnaginsulfonylchloride derivative 6 was afforded, which on amidation using morpholine, a sulonamido derivative (7) was obtained. Alkaline hydrolysis of the latter compound yielded 7-N-morpholinosulsamidobenzofuran (8) which was condensed with some aromatic aldehydes to yield the corresponding chalcone compounds (9a-e). Demethylation of visnagin afforded norvisnagin (10). The reaction of 10 with ethylbromoacetate in dry acetone yielded the ester benzopyran derivative (11) which reacted with hydrazine hydrate to afford the corresponding hydrazide derivative (12) and this was condensed with 3,4,5-trimethoxybenzaldehyde to give the corresponding hydrazone (13). A thaizolidinone derivative (14) was obtained by condensation of (13) with thioglycolic acid. Chloromethylation of norvisnagin afforded a 4-chloromethyl derivative (15) which reacted with different primary and secondary amines to yield the corresponding ethylamino derivative (16a, b). Moreover, mannich bases (16a, b) and (17a-c) were obtained by reacting norvisnagin with different primary and secondary amines in the presence of formalin but benzoylation of (16a, b) and (17a-c) afforded 4-oxybenzoyl derivative (18a-e). The prepared compounds were tested for their interaction with DNA; bromovisnagin 2 showed the highest affinity and compounds 6, 15, 8a, > 14, > 16b, 17a, and 16a showed moderate activity in decreasing potency. Moreover, compound 2 also was the most active as antiviral agent toward HS-I virus and compounds 6, 7, 15, 14, 16a, and 18a were found to be moderately active. CD(50) of the active compounds were also measured.

Development of a fission yeast-based high-throughput screen to identify chemical regulators of cAMP phosphodiesterases

Cyclic nucleotide phosphodiesterases (PDEs) comprise a superfamily of enzymes that serve as drug targets in many human diseases. There is a continuing need to identify high-specificity inhibitors that affect individual PDE families or even subtypes within a single family. The authors describe a fission yeast-based high-throughput screen to detect inhibitors of heterologously expressed adenosine 3',5'-cyclic monophosphate (cAMP) PDEs. The utility of this system is demonstrated by the construction and characterization of strains that express mammalian PDE2A, PDE4A, PDE4B, and PDE8A and respond appropriately to known PDE2A and PDE4 inhibitors. High-throughput screens of 2 bioactive compound libraries for PDE inhibitors using strains expressing PDE2A, PDE4A, PDE4B, and the yeast PDE Cgs2 identified known PDE inhibitors and members of compound classes associated with PDE inhibition. The authors verified that the furanocoumarin imperatorin is a PDE4 inhibitor based on its ability to produce a PDE4-specific elevation of cAMP levels. This platform can be used to identify PDE activators, as well as genes encoding PDE regulators, which could serve as targets for future drug screens.

Bioactive triterpenoids from Vochysia pacifica interact with cyclic nucleotide phosphodiesterase isozyme PDE4

Several species of the genus Vochysia (Vochysiaceae) are used by traditional communities in South America to relieve ailments linked to inflammation, such as skin sores, asthma and pulmonary congestion. As the cAMP phosphodiesterase 4 isozyme (PDE4) is currently considered as an intracellular target for new antiinflammatory drugs, several constituents of Vochysia pacifica Cuatrec., an endemic tree from the Western coast of Colombia, were tested for their ability to inhibit PDE4. Purification of the methanol extract of the stem bark of this species led to the isolation of seven known triterpene derivatives: betulinic acid, sericic acid, 24-hydroxytormentic acid, trachelosperogenin B, 24-hydroxytormentic acid glucosyl ester, quadranoside I and niga-ichigoside F1. One triterpene glycoside, quadranoside I, and two triterpenes, betulinic and sericic acids, exhibited mild inhibitory activity on the isolated PDE4 isozyme.