Elisabete Lima

Nutritional value of selected macroalgae

Macroalgae are traditionally used in human and animal nutrition. Their protein and fiber content have been widely studied and differ according to the species, their geographic origin and their seasonal conditions. In addition to their value for human nutrition, seaweeds have multiple therapeutically applications (e.g., weight control, hypocholesterolemic, antioxidant and antitumor activities, others) and, in general, contribute and promote human health. In the archipelago of the Azores, the consumption of seaweeds is widespread and accepted as a common practice in some islands. This work is aimed at providing information on the protein and fiber content of the locally consumed species, to promote this regional food product that can be potentially profitable from the biotechnology and commercial perspective, and also benefit public health, particularly, taking into account the low level of marine pollution in the Azores archipelago. Protein and fiber content of eight seaweeds (Porphyra sp., Osmundea pinnatifida, Pterocladiella capillacea, Sphaerococcus coronopifolius, and Gelidium microdon, Rhodophyta; Cystoseira abies-marina and Fucus spiralis, Phaeophyta; Ulva compressa, Chlorophyta) were determined using the Kjeldahl method and the Weende method, respectively. The protein content ranged from 6.81 to 26.62 of dry weight for C. abies-marina and U. compressa, respectively. Fiber content was generally higher as compared with that in seaweeds from other origins and ranged from 33.82 to 63.88 for O. pinnatifida and F. spiralis, respectively.

Edible Azorean macroalgae as source of rich nutrients with impact on human health

Fucus spiralis, Porphyra sp. and Osmundea pinnatifida are macroalgae consumed as food in some of the Azorean Islands, but little information is available on their nutritional value. This paper presents information on the nutritional aspects in terms of proteins (9.71-24.82%), lipids (5.23-8.88%), soluble carbohydrates (17.59-25.37%), ash (22.31-38.55%), minerals (0.96-1.82 for Na/K ratios) and fat soluble vitamins A (1.20-1.41%) and E (4.86-51.14%) contents on dry weight basis. Fatty acid (SFA, MUFA, PUFA and n6/n3 and h/H ratios) and amino acid profiles, and antioxidant properties were also reported. All the three species contained measurable quantities of 9 of 10 essential amino acids (41.62-63.50% of the total amino acids). The regular consumption of these algae allied with the low level of seawater pollution around Azores Islands will improve human health conditions and will have a protective effect on the most common degenerative diseases.

HPLC–UV–ESI-MS analysis of phenolic compounds and antioxidant properties of Hypericum undulatum shoot cultures and wild-growing plants

LC-UV and LC-MS analysis were used to study the phenolic composition of water extracts of Hypericum undulatum (HU) shoot cultures and wild-growing (WG) plants. Total phenolic content (TPC), determined using the Folin-Ciocalteu assay, and the antioxidant activity measured by two complementary methods were also performed for each sample. Mass spectrometry revealed several phenolics acids with quinic acid moieties, flavonols, mostly quercetin, luteolin and apigenin glycosides, flavan-3-ols (catechin and epicatechin) and the xanthonoid mangiferin. Differences in phenolic composition profile and TPC were found between the samples. The major phenolic in HU culture-growing (CG) samples is chlorogenic acid, followed by epicatechin, quercitrin and isoquercitrin. The WG plants presents hyperoside as the main phenolic, followed by isoquercitrin, chlorogenic acid and quercetin. The TPC and antioxidant activity were higher in samples from WG plants.

Comparison of the endemic Azorean Hypericum foliosum with other Hypericum species: antioxidant activity and phenolic profile

Water extracts of Hypericum foliosum (HF) from five Azorean Islands were analysed for their antioxidant activity and total phenolic contents. The results were compared with those from medicinal Hypericum species (H. perforatum, H. androsaemum and H. undulatum) and also with Azorean green tea. HF exhibited strong scavenging activity (87–91%) and moderate inhibition of linoleic acid oxidation (56–72%), and presented no significant difference to the other studied plants; in contrast, the synthetic antioxidant butylated hydroxyltoluene showed antioxidant activity values of 22% and 88%, respectively. The average value of phenolics in HF was higher than that in the other Hypericum species and lower than that in tea. Additionally, the phenolic profiles of the Hypericum species were compared by reverse phase-high performance liquid chromatography/ultraviolet (RP-HPLC/UV). The method presented permits the simultaneous determination of phenolic acids, flavonoids, hypericin and hyperforin within 55 min. The most similar profile was observed between HF and H. androsaemum. This study indicates that HF is a source of bioactive compounds with potential health benefits.

Pentacyclic triterpenes from Euphorbia stygiana

Two pentacyclic triterpenes, D-friedomadeir-14-en-3beta-yl acetate and D:C-friedomadeir-7-en-3beta-yl acetate, named madeiranyl acetate and isomadeiranyl acetate, respectively, were isolated from leaves of Euphorbia stygiana, together with the two known madeiranes, D-friedomadeir-14-en-3-one and D:C-friedomadeir-7-en-3-one, which were obtained from the stem bark. In addition, four known lupane and taraxerane-type triterpenes, namely lupenyl acetate, lupenone, taraxeryl acetate and taraxerone, were also isolated from the same source. Structures were elucidated by physical, chemical and spectroscopic methods (1H NMR, 13C NMR, IR and mass spectra) and by comparison with literature data, and in the case of D:C-friedomadeir-7-en-3beta-yl acetate by X-ray analysis as well.

Angiotensin I-converting enzyme (ACE) inhibitory activity of Fucus spiralis macroalgae and influence of the extracts storage temperature-A short report.

Recently, increasing attention has been paid to the marine algae as a natural source of novel angiotensin-I converting enzyme (ACE) inhibitors, such as the phlorotannins that are the predominant polyphenols in brown algae. This study reports, for the first time, the ACE inhibition of methanol extract/fractions from Azorean brown algae Fucus spiralis (Fs) determined by HPLC-UV method, their total phenolic content (TPC) quantified as phloroglucinol equivalents (PE) and the effect of the Fs dry powder methanol extracts (Fs-DME) storage temperature on ACE inhibition. The results indicate that the ACE inhibition of Fs-DME decreased by 28.8% and 78.2% when stored during 15days at -80°C and -13°C, respectively, as compared with the activity of Fs-DME at a refrigerated temperature of 6°C and assayed immediately after extraction that showed a value of 80.1±2.1%. This Fs-DME sample was fractionated by ultrafiltration membranes into three molecular weight ranges (<1kDa, 1-3kDa and >3kDa), presenting the fraction>3kDa remarkably high ACE inhibition (88.8±2.4%), TPC value (156.6±1.4mg PE/g of dry weight fraction) and yield. Furthermore, chromatographic and spectrophotometric analyses corroborate that phenolic compounds were present in Fs methanol extract/fractions, and also revealed that phloroglucinol occurs in Fs. The results seem to suggest that Azorean Fs can be a source of powerful ACE-inhibitory phlorotannins with potential impact on public health, particularly on hypertensive patients.

Health-promoting ingredients from four selected Azorean macroalgae

This study presents, for the first time, the nutritional and health promoting aspects of four selected Azorean macroalgae (Ulva compressa, Ulva rigida, Gelidium microdon and Pterocladiella capillacea) in terms of total lipids, fatty acids (FA) profile, n6/n3 and hypocholesterolemic (h)/hypercholesterolemic (H) FA ratios, minerals, total essential amino acids (AA), anti-ageing and anti-phenylketonuria AA content, coenzyme Q10, α-tocopherol, total phenolics, antioxidant properties and energy value, on a dry weight basis. The results revealed low lipid content (1.02-4.32%) but significant PUFA content (29.57-69.22% of total FA), suitable FA ratios (0.48-9.49 for n6/n3 and 1.26-4.22 for h/H), balanced macromineral ratios (0.27-1.91 for Na/K and 0.15-1.07 for Ca/Mg), appreciable amount of essential AA (45.27-58.13% of total AA), high amount of anti-ageing AA, low Phe content, coenzyme Q10 (1.25-8.27μg/g), α-tocopherol (2.61-9.14mg/100g), high total phenolic content (27.70-55.07mg of gallic acid equivalents/g extract), significant free radical scavenging activity (29.32-47.73%) and valuable energy content (6.80-9.80kJ/g). A regular consumption of these algae either directly or through food supplements may improve human health or may have a protective effect on some diseases and ageing process. They can also be used for producing pharmaceuticals and cosmeceuticals with potential economic value.

Bovine Milk Formula Based on Partial Hydrolysis of Caseins by Bromelain Enzyme: Better Digestibility and Angiotensin-Converting Enzyme-Inhibitory Properties

A new methodology was developed using bromelain as a proteolytic enzyme for the production of a partially hydrolyzed bovine milk formula, without changing the milks organoleptic and nutritional properties. This study also revealed that the in vitro angiotensin-converting enzyme inhibition increased in the modified milk as compared with the control sample, showing the highest angiotensin-converting enzyme-inhibitory activity for fractions with molecular weights between 3 and 10 kg mol−1. The Lineweaver-Burk plot revealed that the produced milk formula acted as a non-competitive inhibitor, as determined by high performance liquid chromatography.

Molluscicidal activity of crude water and hexane extracts of Hypericum species to snails (Radix peregra)

In spite of intense research on both chemical constituency and biological activity of Hypericum species, potential applications of their active components for pest control have been less well investigated. In the present study, Hypericum androsaemum (tutsan), Hypericum foliosum (malfurada), and Hypericum undulatum (wavy St. Johns wort) aqueous and hexane extracts were studied for their molluscicidal and ovicidal activities against Radix peregra. The molluscicidal activity of the aqueous extracts was low, except for H. androsaemum infusion (median lethal concentration [LC50](adults)  = 317.1 ppm; LC50(juveniles)  = 415 ppm), and less important compared with the toxicity of all three hexane extracts tested: H. androsaemum (LC50(adults)  = 30.47 ppm; LC50(juveniles)  = 73.25 ppm), H. undulatum (LC50(adults)  = 30.55 ppm; LC50(juveniles)  = 60.54 ppm), and H. foliosum (LC50(adults)  = 48.61 ppm; LC50(juveniles)  = 38.81 ppm). An ovicidal effect was observed only with H. androsaemum infusion (1.85% of hatching at 500 ppm) and H. foliosum hexane extract (0.0% of hatching at 100 ppm). A preliminary phytochemical investigation of the lipophylic extracts from these Hypericum sp. revealed a different chemical profile and confirmed the presence of ursolic acid only in H. undulatum as the main compound. The present study indicates that products from hexane extracts of the Hypericum sp. analyzed may be used as potential molluscicides to control snails responsible for transmitting fasciolosis.

Nutritional and Functional Bioactivity Value of Selected Azorean Macroalgae: Ulva compressa, Ulva rigida, Gelidium microdon, and Pterocladiella capillacea

This study presents information on the biochemical composition (dry weight basis), nutritional aspects, and angiotensin I-converting enzyme (ACE) inhibitory properties of selected macroalgae (Ulva compressa, Ulva rigida, Gelidium microdon, and Pterocladiella capillacea) from Azores. Moisture content was very high (83.2% to 90.0% of fresh weight). Total dietary fiber (33.7% to 41.0%) that presented a good balance of both soluble and insoluble fibers (15.5% to 19.2% and 18.2% to 21.8%, respectively) was the most abundant component in these macroalgae. Protein and ash (ranged from 15.7% to 23.4% and 10.7% to 20.7%, respectively) were the 2nd most abundant components in red and green macroalgae, respectively. Moderate soluble carbohydrate contents (14.5% to 19.8%) were found in all species. Lipid contents were low (1.0% to 4.3%), particularly in Ulva species (1.0% to 1.7%), but contained higher unsaturated fatty acids (FAs) (7.5% to 32.9% and 29.6% to 69.2% of total FA for monounsaturated fatty acid and polyunsaturated fatty acid groups, respectively) than saturated fatty acid (23.3% to 46.8% of total FA) contents. All the macroalgal proteins had high digestibility in vitro (82.2% to 89.4%, relatively to sodium caseinate), contained high quantity of essential amino acids (45.3% to 58.1% of total amino acids), but in different proportions, and were rich in aspartic and glutamic acids that together account for 17.2% to 36.2% of the total amino acids. These results suggested that regular consumption of the selected macroalgae may improve human health and revealed that they can be used for producing food supplements for human and animal nutrition and/or pharmaceuticals with potential effect on the regional economy. Furthermore, the ACE-inhibitory IC50 values of 0.095 to 0.695 mg/mL for the <1 kDa protein hydrolysate fraction revealed a potential impact on hypertension disorder.