Antiviral activity of Distictella elongata (Vahl) Urb. (Bignoniaceae), a potentially useful source of anti-dengue drugs from the state of Minas Gerais, Brazil

AIMS

To investigate the in vitro antiviral activity of Distictella elongata (Vahl) Urb. ethanol extracts from leaves (LEE), fruits (FEE), stems and their main components.

METHODS AND RESULTS

The antiviral activity was evaluated against human herpesvirus type 1 (HSV-1), murine encephalomyocarditis virus (EMCV), vaccinia virus Western Reserve (VACV-WR) and dengue virus 2 (DENV-2) by the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. LEE presented anti-HSV-1 [EC(50) 142.8 ± 5.3 μg ml(-1); selectivity index (SI) 2.0] and anti-DENV-2 activity (EC(50) 9.8 ± 1.3 μg ml(-1) ; SI 1.5). The pectolinarin (1) isolated from LEE was less active against HSV-1 and DENV-2. A mixture of the triterpenoids ursolic, pomolic and oleanolic acids was also obtained. Ursolic and oleanolic acids have shown antiviral activity against HSV-1. A mixture of pectolinarin (1) and acacetin-7-O-rutinoside (2) was isolated from FEE and has presented anti-DENV-2 activity (EC(50) 11.1 ± 1.6 μg ml(-1) ; SI > 45). Besides the antiviral activity, D. elongata has disclosed antioxidant effect.

CONCLUSIONS

These data shows that D. elongata has antiviral activity mainly against HSV-1 and DENV-2, besides antioxidant activity. These effects might be principally attributed to flavonoids isolated.

SIGNIFICANCE AND IMPACT OF THE STUDY

Distictella elongata might be considered a promising source of anti-dengue fever phytochemicals.

High-speed countercurrent chromatography as a valuable tool to isolate C-glycosylflavones from Cecropia lyratiloba Miquel

A new apigeninglycoside, apigenin 6-C-galactosyl-6"-O-beta-galactopyranoside (1), isoorientin, and a mixture of orientin and isovitexin were isolated from leaves of Cecropia lyratiloba by high-speed countercurrent chromatography using a solvent system containing ethyl acetate, butanol, methanol and water. The structural elucidation of 1 was based on NMR spectroscopy.

Campomanesia lineatifolia Ruiz & Pav. as a gastroprotective agent

ETHNOPHARMACOLOGICAL RELEVANCE

Campomanesia lineatifolia Ruiz and Pav. (Myrtaceae) is a native edible species found in the Amazon Rainforest, commonly known as gabiroba. In Brazil, Campomanesia species are frequently used in traditional medicine for gastrointestinal disorders.

MATERIALS AND METHODS

The present study performed phytochemical analyses and determined both the in vitro antioxidant activity of the ethanolic extract of Campomanesia lineatifolia leaves (EEC) as well as its ethyl acetate fraction (EAFC). In this analysis, quercetin was used as a positive control. Gastroprotective activity was also investigated at different oral doses in two experimental models in rats - gastric lesion induced by ethanol and gastric lesion induced by indomethacin. In this analysis, cimetidine and sucralfate were used as positive controls. The area of gastric lesion underwent macroscopic and histomorphometric evaluations, while the mucus content was estimated by applying the periodic acid-Schiff stain. Oral acute toxicity was also assessed.

RESULTS

Phytochemical studies revealed the presence of flavonoids and tannins. Catechin and quercitrin were isolated by bioguided chromatographic fractionation of EAFC. EEC and EAFC presented in vitro antioxidant activity. The oral administration of EEC and EAFC at doses 100-400 mg/kg (ethanol model) and at doses of 400-1200 mg/kg (indomethacin model) proved to be effective in preventing gastric ulcerations in rats. Pretreatment with EAFC (400mg/kg) significantly increased the gastric mucus content in the ethanol model. No animals died during the acute oral toxicology test.

CONCLUSIONS

Results confirm the Brazilian ethnopharmacological use of Campomanesia lineatifolia as a gastroprotective agent and indicate that the anti-ulcer effect is most likely mediated by scavenging free radicals due to the polyphenol content and, at least in part, by increasing the mucus secretion and the mucosal defense. In addition, EEC and EAFC were found to be safe when applied to a 2000 mg/kg single oral dose.