Anti-inflammatory, antiallergic and COVID-19 protease inhibitory activities of phytochemicals from the Jordanian hawksbeard: identification, structure-activity relationships, molecular modeling and impact on its folk medicinal uses.

On Wednesday 11th March, 2020, the world health organization (WHO) announced novel coronavirus (COVID-19, also called SARS-CoV-2) as a pandemic. Due to time shortage and lack of either a vaccine and/or an effective treatment, many trials focused on testing natural products to find out potential lead candidates. In this field, an edible and folk medicinal Jordanian plant Crepis sancta (Asteraceae) was selected for this study. Phytochemical investigation of its enriched polyphenolic extract afforded four eudesmane sesquiterpenes (1-4) together with (6S,9R)-roseoside (5) and five different methylated flavonols (6-10). Structure elucidation of isolated compounds was unambiguously determined based on HRESIMS, X-ray crystallography, and exhaustive 1D and 2D NMR experiments. All isolated compounds were assessed for their in vitro anti-inflammatory, antiallergic and in silico COVID-19 main protease (Mpro) inhibitory activities. Among the tested compounds, compounds 5-10 revealed potent anti-inflammatory, antiallergic and COVID-19 protease inhibitory activities. Chrysosplenetin (10) is considered as a promising anti-inflammatory and antiallergic lead structure adding to the phytotherapeutic pipeline. Moreover, its inhibitory activity against SARS-CoV-2 Mpro, supported by docking and molecular dynamic studies, strengthens its potential as a lead structure paving the way toward finding out a natural remedy to treat and/or to control the current COVID-19 pandemic.

In vivo antiulcer activity, phytochemical exploration, and molecular modelling of the polyphenolic-rich fraction of Crepis sancta extract.

Bioactivity-guided investigation of the methanol extract of Crepis sancta aerial parts, collected off Al-Tafilah, South Jordan, was applied, and in this study, the extract was explored for its phytochemical components and in vivo antiulcer activity. In addition, a docking study involving the purified compounds with the newly crystalized gastric proton pump (PDB # 5YLU) was performed. In-depth phytochemical investigation using the state-of-the-art chromatographic and analytical techniques was implemented resulting in the identification of two eudesmane-type sesquiterpenoids, 3-oxo-γ-costic acid (1) and its methyl ester (2) together with seven different methoxylated flavonols (3-9) as the extract's major components. The in vivo antiulcer study at three different doses (50, 100, and 200 mg/kg) against ethanol-induced gastric ulcer in male albino rats, compared to omeprazole (20 mg/kg) as a standard proton pump inhibitor antiulcer drug, revealed that the tested extract, at the middle and the highest doses, featured comparable or even superior activities relative to omeprazole as deduced from histopathological examination, in particular with regard to reducing inflammatory cell infiltration and ceasing mucosal haemorrhage. The tested extract revealed also a dose-dependent reduction in the volume and titrable acidity of the gastric juice together with a dose-dependent increase in the protective gastric mucin content which may explain the noticeable gastroprotective effect. Molecular modelling study of the isolated compounds showed a binding mode similar to the co-crystallized substrate vonoprazan in 5YLU which strengthens the importance of the tested extract as a potential natural remedy for treating gastric ulcer.

Gastroprotective activity of Loranthus acaciae flower extract in a rodent model of ethanol-induced ulcer.

Loranthus acaciae (Loranthaceae) is a perennial green semi-parasitic plant used in ethnopharmacological medicine for healing wounds. The protective effect of L. acaciae on gastric ulcer induced by ethanol was investigated in a rat model. Ulcer index and total glutathione level were measured and histological and immunohistochemical studies for the expression of cyclooxygenase-2 were performed. Furthermore, chemical constituents of the flower extract were analyzed. Ulcer index was significantly lowered in L. acaciae-treated groups. Protection ratios were 75.9%, 98.9%, and 70.7% for 250 mg/kg and 500 mg/kg of L. acaciae and 40 mg/kg of esomeprazole, respectively. Histological examination revealed fewer hemorrhage in mucosa and less edema in submucosa of L. acaciae-treated groups compared with control. In the esomeprazole-treated group, there was mild disruption in the surface epithelium and mild hemorrhage. However, edema and leucocytes infiltration in the submucosa layer were present. Immunohistochemical staining of stomach sections for cyclooxygenase-2 (COX-2) was negative in the control group as well as in the L. acaciae-treated groups. Total glutathione level in mucosa layer of the stomach was higher in L. acaciae-treated groups compared with control. Liquid chromatography-mass spectrometric analysis revealed the presence of loranthin and rutin as the major constituents. It can be concluded that L. acaciae imparted a gastroprotective action against ethanol-induced ulcer in rats. Novelty 500 mg/kg L. acaciae protected the stomach by 98.9% from ulcerogenic effect of ethanol. L. acaciae increased total glutathione level but not COX-2 expression in gastric mucosa. Loranthin and rutin were the major constituents in L. acaciae flower extract.

Regression of endometrial implants treated with vitamin D3 in a rat model of endometriosis.

Endometriosis is one of the most frequent gynecological diseases. In addition to their side effects, available medical therapies may decrease fertility. Current understanding of endometriosis focuses on the role of the immune system in its pathophysiology. Recent research shed light on the immunomodulatory effect of vitamin D3. Thus, this study was designed to study the effect of vitamin D3 on regression of endometriotic implants in a rat surgical model. Vitamin D3 reduced cyst cross sectional area by 48.8%. Histologically, vitamin D treatment produced fibrosis as well as apoptosis in the stroma. The results of the present study suggest that vitamin D3 administration may have a beneficial effect in treating endometriosis.

Sunitinib as an anti-endometriotic agent.

Endometriosis is one of the most frequent diseases in gynecology. Currently available medical therapies for this disease are unsatisfactory. Based on current understanding of the pathogenic mechanisms in endometriosis especially the similarity between this disease and cancer, this study was designed to investigate the efficacy of the anticancer drug sunitinib in treating endometriosis. The effect of sunitinib on regression of endometriotic implants was studied in a rat surgical model. Sunitinib reduced cyst cross sectional area by 78.8% and caused complete cyst disappearance in 50% of the animals. Histologically, extensive fibrosis was detected in sunitinib-treated group with positive reaction in TUNEL assay indicating that apoptosis is a mechanism of action.

ß-Caryophyllene causes regression of endometrial implants in a rat model of endometriosis without affecting fertility.

Many studies have shown that anti-inflammatory agents are effective in the treatment of endometriosis. ß-Caryophyllene exerted a potent anti-inflammatory effect in vivo. However, its effect on endometriosis has not been investigated. This study aims at investigating the effect of ß-caryophyllene on endometriosis and on fertility and reproduction in adult female rats. Autologous fragments of the endometrium were implantated in the peritoneal cavity in adult female rats. The growth of the endometriotic implants that developed after four weeks was recorded. Treatment started then with ß-caryophyllene (10 mg/kg or 30 mg/kg) or vehicle (control) for 21 days and the growth of the endometriotic implants was measured again. In fertility studies, female rats that received ß-caryophyllene or vehicle were mated and reproductive functions were observed including number and viability of implants, number of corpora lutea, length of pregnancy and outcome of litter. ß-Caryophyllene (10 mg/kg) suppressed the growth of endometriotic implants by 52.5% compared with controls. Also ß-caryophyllene produced apoptosis in luminal epithelim of the cyst as well as in endothelial cells of blood vessels. Ultrstructural studies revealed the presence of active mast cells and eosinophils in both control and ß-caryophyllene-treated rat cysts. No statistically significant difference was observed in any studied parameter between control and ß-caryophyllene-treated groups in fertility study. Therapy with ß-caryophyllene may present a promising novel, non-toxic therapeutic option for patients with endometriosis.

Ethosuximide and phenobarbital promote wound healing via enhancing collagenization.

The fact that ethosuximide (ETO), phenobarbital (PHO), and barbituric acid (BARB) share structural and pharmacophoric homologies with phenytoin and allantoin, both known to have significant wound-healing properties, prompted us to evaluate them as wound-healing agents. Accordingly, ETO-, PHO-, and BARB-containing ointments were applied onto full-thickness excision and incision wounds created on the dorso-lumbar region of experimental rats. ETO-and PHO-treated incision wounds illustrated significant enhancement in breaking strengths (1380 ± 61 and 1240 ± 42 g, respectively) compared to vehicle controls (1070 ± 18 g) and BARB (1080 ± 45 g). Moreover, biochemical analyses revealed significant increase in hydroxyproline contents in ETO- and PHO-treated wounds compared to vehicle controls. Histological evaluation revealed that both ETO and PHO promoted collagen synthesis and deposition. This is the first time to describe the significant wound-healing merits of ETO and PHO as potential clinical agents for treatment of chronic wounds.

Thujone corrects cholesterol and triglyceride profiles in diabetic rat model.

Thujone, which is the major constituent in Salvia sp. (Lamiaceae), was found to correct the lipid profile (cholesterol and triglycerides) in diabetic rats. Oral treatment with thujone (5 mg kg⁻¹ body weight dose) significantly adjusted cholesterol and triglyceride levels in diabetic rats (p ≤ 0.05) to normal levels compared to diabetic untreated rats. This provides a premise in the field of finding new agents to treat diabetic complications.

Antifertility effect of ethanolic extract of Juniperus phoenica (L.) in male albino rats.

The plant Juniperus phoenica (L.) (Cupressaceae) is widely growing on the rocky soils of the Mediterranean regions. In Jordan, the plant is distributed in different locations and is used as a folk medicine to treat rheumatism, edema, and urinary tract diseases. This study aimed to investigate the antifertility effect of J. phoenica in male albino rats. Animals were administered single daily intraperitoneal injections of 400 or 800 mg/kg of J. phoenica cones ethanol extract or the vehicle (dimethyl sulfoxide) for 21 consecutive days. A marked dose-dependent decrease in the counts and motility of the sperms collected from the cauda epididymis of treated rats was observed compared with the control. Furthermore, pregnancy rate in females markedly reduced by 60% and 80% after mating with males treated with 400 or 800 mg/kg, respectively. At the same time, significant decreases were detected in seminal vesicles and testicular weight of rats that received 800 mg/kg as compared with control rats. Testosterone levels were decreased significantly in both treated groups as compared with control. Histologically, seminiferous tubules of treated rats showed marked arrests of spermatogenesis and a marked decrease in the number of mature sperms. Therefore, the results of this study suggest that the ethanolic extract of the cones of J. phoenica possesses potential antifertility effects.