María del Rosario Fusco

Biochemical Composition, Antimicrobial Activities,and Anti–Quorum-Sensing Activities of Ethanol and Ethyl Acetate Extracts from Hypericum connatum Lam. (Guttiferae)

We studied the polyphenol composition and antioxidant activity of the ethanolic and ethyl acetate extracts of Hypericum connatum (Guttiferae), in addition to their antimicrobial and antiquorum-sensing (AQS) properties. The extracts exhibited a similar polyphenol content and a notable antioxidant activity, which was stronger in the ethanolic extract (EC50=3.2 μg/mL). Ultrahigh-performance liquid chromatography analyses revealed different polyphenol profiles, with rutin and apigen being the main components of the ethanolic extract and caffeic acid, (-)-epicatechin and p-coumaric acid being abundant in the ethyl acetate extract. The ethyl acetate extract exhibited a more effective antimicrobial activity than the ethanolic extract against the pathogens Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa. For the first time, AQS activity was detected in H. connatum: the ethanolic extract inhibited the production of violacein, a quorum-sensing-regulated pigment, in a Chromobacterium violaceum tester strain, without interfering with its growth.

Anti-inflammatory properties from isolated compounds of Cyclolepis genistoides

Context: Cyclolepis genistoides D. Don (Asteraceae) is an Argentinean endemic shrub, known by the vernacular name “palo azul” or “matorro negro”. It is widely used in folk medicine as a diuretic, an antirheumatic, and an antispasmodic agent. Objective: The aim of this work was to describe the activity of two isolated compounds of C. genistoides, oleanolic acid (1) and deacylcynaropicrin (2), using the carrageenan-induced paw edema method in mice. Materials and methods: Aerial parts of C. genistoides were dried, powdered, and extracted with petroleum ether, ethyl acetate, dichloromethane, and methanol for 48 h. The fractions obtained from the ethyl acetate extract yielded oleanolic acid, while deacylcynaropicrin was obtained according to Abdei-Mogib et al. Structures were elucidated by 1H-NMR and 13C-NMR. The products were administered intraperitoneally at doses of 40, 75, and 100 mg/kg. Results and discussion: Compound 1 exhibited significant activity during the first 7 h of the inflammatory phase (at 1, 3, 5, and 7 h), exercising its inhibitory action on inflammation mediated by histamine, prostaglandins, serotonin, and kinins, while compound 2 showed a significant inhibition at 3 and 5 h contributing to this effect, acting in the intermediate phase. Conclusions: According to the results of this work, the intraperitoneal administration of oleanolic acid and deacylcynaropicrin isolated from the aerial parts of C. genistoides produced a significant inhibition of carrageenan-induced inflammation at doses of 75 and 100 mg/kg. These results give support to the use of this plant as an anti-inflammatory in traditional medicine.

The protective effect of Hypericum connatum on stress-induced escape deficit in rat is related to its flavonoid content.

Abstract Context Hypericum perforatum L. (Hypericaceae), used in moderate depression treatment, is active in experimental tests for antidepressant activity. For H. connatum Lam., a South American species lacking hyperforin, antidepressant effects have not been demonstrated. Objective This study evaluates the antidepressant-like effect of H. connatum in rats and identifies the components involved in this activity. Materials and methods First, the effects of acute and 14-d oral administrations of an extract derived from H. connatum aerial parts were studied using the Escape Deficit (ED) test. Next, methanol-extracted flavonoid-enriched fractions B and C and fraction-purified flavonoids (quercetin, rutin and isoquercitrin) were evaluated in the ED test after acute administration. To rule out possible confounding effects of the flavonoids, we examined nociceptive threshold using the tail-flick test and anxious behaviour using the elevated plus maze (EPM) test. Results Hypericum connatum increased reactivity of unavoidable stress-exposed rats after acute (0.5 and 1 g/kg: ED = 18.6/30 and 19.8/30, respectively) and repeated administration (0.5 g/kg twice daily: ED = 17.8/30). Protective effects were observed for fractions B and C (250 mg/kg: ED = 18.1/30 and 18.8/30, respectively), quercetin (2.5, 5 and 10 mg/kg: ED = 15.3/30, 18.3/30 and 21.6/30, respectively), rutin (5 and 10 mg/kg: ED = 15.4/30 and 13.0/30, respectively) and isoquercitrin (2.5 mg/kg: ED = 19.2/30). The flavonoids did not modify nociceptive threshold or performance in the EPM test. Discussion and conclusion Hypericum connatum showed protective activity in the ED test, a correlate of potential antidepressant-like effects that appeared to be related to the flavonoid components of this species.

Anti-inflammatory Activity and Antioxidant Potential of Aqueous Extracts from Stem Bark of Geoffroea decorticans

In the present work we investigated, for the first time, the anti-inflammatory activity and the antioxidant properties of aqueous and ethanolic extracts, obtained from stem bark of Geoffroea decorticans (Gill. ex Hook. et Arn.) Burk. (Fabaceae). G. decorticans, commonly known as “chañar” or “chañarcillo”, is a traditional argentinean plant used as emollient, balsamic, antitussive, expectorant and anti-inflammatory. The stem bark was collected from San Francisco del Monte de Oro, San Luis, Argentina. Anti-inflammatory activity was evaluated by carrageenan-induced paw edema in rats. Antioxidant activity was tested using 1,1-Diphenyl-2-picrylhydrazyl radical-scavenging activity (DPPH), 2,2 ́-Azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical scavenging activity (ABTS) and ferric ion-reducing power (RP-Fe) assays. Aqueous extract 10% p/v showed anti-inflammatory activity (3h, 48% inhibition, 5h 37% inhibition and 7h 17% inhibition) and antioxidant activity (DPPH, IC50 (mg/mL) = 0.098 ± 0.032; ABTS, IC50 (mg/mL) = 0.022 ± 0.343, RP-Fe IC50 (mg/mL) = 1.124 ± 0.146). In the other hand, the ethanolic extract 5% p/v, presented anti-inflammatory activity (3h, 34% inhibition, 5h 38% inhibition and 7h 35% inhibition) and antioxidant activity (DPPH, IC50 (mg/mL) = 0.133 ± 0.027; ABTS, IC50 (mg/mL) = 0.086 ± 0.262, RP-Fe IC50 (mg/mL) = 7.089 ± 0.104). These results suggest that, also fruits, the aqueous and ethanolic extracts from the stem bark of G. decorticans present significant anti-inflammatory activity and antioxidant properties.

Antidiarrhoeal activity of Aristolochia argentina Gris. (Aristolochiaceae) in rodents

The roots of Aristolochia argentina are used in folk medicine for the treatment of colitis, diarrhoea and hemorrhoids. In this study, based on ethnobotanical lead, we evaluated the antidiarrhoeal activity of Aristolochia argentina lyophilized aqueous extract (AALE) in rats and mice using various models. The castor oil and magnesium sulphate induced diarrhoea, the small intestinal transit in mice and the intestinal fluid accumulation were used in this study. At the doses of 62.5, 125 and 250 mg/kg p.o., the AALE showed significant antidiarrhoeal activity in both models. The AALE significantly reduced the intestinal fluid accumulation in the castor oil induced enteropooling. AALE delays small intestinal transit possibly, at least in part, involving opioid and α2-adrenergic receptors. The phytochemical analysis revealed the presence of carbohydrates, flavonoids, tannins, saponins and anthraquinones. The results suggest that AALE showed antidiarrhoeal activity by inhibiting intestinal motility and enteropooling property, justify its use in traditional medicine.