ISOLAMENTO E CARACTERIZAÇÃO DE PRINCÍPIOS ACTIVOS DE PLANTAS PARA O COMBATE À TUBERCULOSE

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Characterization of phenolic compounds and antioxidant activity of ethanolic extracts from flowers of Andryala glandulosa ssp. varia (Lowe ex DC.) R.Fern., an endemic species of Macaronesia region

Publication . Gouveia, Sandra; Gonçalves, João; Castilho, Paula C.

Andryala glandulosa spp. varia (Lowe ex DC.) R.Fern. (Asteraceae), is a small shrub that grows in moun tains of Madeira Island, Fuerteventura and Lanzarote from Canary Islands. The flowerheads are used traditionally for the treatment of edemas and in homemade dermo-cosmetic preparations. In this paper the chemical composition of the extracts of this plant, used in folk medicine, and their antioxidant capacity were established; the presence of potentially harmful lactones, so commonly associated with related species used for the same purposes was also evaluated. A reversed-phase high performance liquid chromatography method (RP-HPLC) coupled with diode-array detection (DAD) and electrospray ionization mass spectrometry (ESI/MSn) was used for the characterization of phenolic com pounds in ethanol extracts of flowers from A. glandulosa spp. varia collected in Madeira Island. Total phenolic content (TPC) and total flavonoid content (TFC) were established and three assays (DPPH, ABTS and FRAP) were used to measure the antioxidant capacity of the dichloromethane and ethanol extracts. The dichloromethane extract of A. glandulosa contain long linear chain hydrocarbons and esters. In the alcoholic extracts, a total of 16 compounds were characterized based on their UV, mass spectra and HPLC retention time. Quinic acid and luteolin derivatives were found to be the main compounds. Quantification of caffeoylquinic acids (CQA) detected was performed by HPLC-DAD and 5-O-CQA and 3,5-O-diCQA were the major compounds (with values of 22.40 ± 0.21 and 59.69 ± 1.07 mg/100 g dried plant, respectively). Only the ethanol extract was active, revealing a high radical scavenging capacity and a moderate reducing potential. The potent antioxidant alcoholic extracts are composed mainly of hydroxycinnamic acid derivatives and flavonoids. The presence of sesquiterpene lactones was not detected. Since lactones are very common among related plants, like arnicas, and known to cause dermatitis and other unwanted effects, this can be an explanation for the preference for Andryala over other more easily available alternatives

2013Journal article

Open access

Antioxidant capacity, cytotoxicity and antimycobacterial activity of Madeira Archipelago endemic helichrysum dietary and medicinal plants

Publication . Gouveia-Figueira, Sandra C.; Gouveia, Carla A.; Carvalho, Maria J.; Rodrigues, Ana I.; Nording, Malin L.; Castilho, Paula C.

The potential bioactivity of dietary and medicinal endemic Helichrysum plants from Madeira Archipelago was explored, for the first time, in order to supply new information for the general consumer. In vitro antioxidant properties were investigated using DPPH, ABTS(•+), FRAP and β-Carotene assays, and the total phenolic content (TPC) and total flavonoid content (TFC) were also determined. Although the results generally showed a large variation among the three analyzed plants, the methanolic extracts showed the highest antioxidant capacity. Exception is made for H. devium n-hexane extract that showed good radical scavenger capacity associated to compounds with good reducing properties. In the Artemia salina toxicity assay and antimycobaterial activity, H. devium was the most potent plant with the lowest LD50 at 216.7 ± 10.4 and MIC ≤ 50 μg·mL(-1). Chemometric evaluation (Principal Component Analysis-PCA) showed close interdependence between the ABTS, TPC and TFC methods and allowed to group H. devium samples.

2014-10-31Journal article

Open access

Phenolic composition and antioxidant capacity of cultivated artichoke, Madeira cardoon and artichoke‐based dietary supplements

Publication . Gouveia, Sandra C.; Castilho, Paula C.

Cynara cardunculus var. scolymus (artichoke) and Cynara cardunculus var. ferocissima (Madeira cardoon) are two Asteraceae plants used in Madeira Archipelago in diet and also for medicinal issues. The present work aimed to compare the phenolic composition and quantify the main compounds of these two plants and two artichoke based dietary supplements (juice and dragées). The methanolic extract of the endemic plant cardoon was basi cally composed of caffeoylquinic acid isomers. The same compounds were observed in artichoke extract, where there was a larger number and variety of other phenolic compounds. Variations in qualitative and quantitative composition of the three artichoke based products were extensive, with only 3 components being common to all 3 products. Mono-O-diglycosilated flavonoids (luteolin, apigenin and quercetin) were found in the artichoke products but not in Madeira cardoon. 1,3-O-dicaffeoylquinic acid (cynarin), usually considered mainly responsi ble for the biological properties of artichoke, was found in high amounts ranging in most samples but was not detected in the analyzed commercial dragées. The antioxidant assays results reflected the highly diversified com position of the artichoke-based products, showing a high radical scavenger and reducing capacities, while the ex tract from Madeira cardoon was a poor antioxidant

2012Journal article

Open access

Artemisia annua L.: Essential oil and acetone extract composition and antioxidant capacity

Publication . Gouveia, Sandra C.; Castilho, Paula C.

Aerial parts of Artemisia annua growth in three different locations of Madeira Archipelago were studied. The essential oil composition was established by GC-MS and the main components were mono- and sesquiterpenes; artemisia ketone was not detected. The presence of phenolic compounds in the acetone extracts was investigated by HPLC-DAD-ESI/MSn and a diversified phenolic profile of 40 hydrocinnamic acid derivatives and glycosylated flavonoids was found. A few compounds were reported for the first time in Artemisia annua. The antioxidant capacity of essential oils and extracts were measured by three different in vitro assays. For the essential oils, a very good antioxidant response was found and the extracts also showed a good antioxidant capacity, in particular as antiradical scavengers.

2013Journal article

Open access

Phenolic screening by HPLC–DAD–ESI/MSn and antioxidant capacity of leaves, flowers and berries of Rubus grandifolius Lowe

Publication . Gouveia-Figueira, Sandra C.; Castilho, Paula C.

In Madeira Island (Macaronesia Island), Rubus grandifolius Lowe berries, locally known by amoras, are widely consumed fresh or processed as jam, juice or liquor. Folk medicine describes R. grandifolius Lowe fruits and leaves being used to treat diabetes, as depurative, diuretic and to relieve sore throat. The aim of this study was to investigate phenolic composition and antioxidant capacity of the different edible parts of the plant (berries, leaves and flowers). HPLC–DAD–ESI/MSn was used to establish the phe nolic profile. Phenolic monomers such as flavonol O-glycosilated (quercetin and kaempferol), quinic acid and caffeic acid conjugates were characterized using the electrospray source in the negative mode; while positive mode was employed to detect glycosylated anthocyanins (cyanidin, delphinin and petunidin). The berries presented a higher radical scavenger capacity (DPPH and ABTS assays) and reducing prop erties (FRAP) than the leaves and the flowers. Ethanolic extracts showed highest antioxidant capacity when compared with water based extracts: DPPH values of 147.9 ± 0.7 mol eq Trolox/g DM; ABTS value of 255.8 ± 1.9 mol eq Trolox/g DM and FRAP value 9455 ± 29 mmol Fe(II)/mgDM).

2015Journal article

Open access