Natural Products Journal, The - Volume 3, Issue 2, 2013

Shrimp processing waste is the single largest industrial waste in Tunisia causing diverse environmental problems. Extraction of astaxanthin from the shell waste of the deep-water pink shrimp (Parapenaeus longirostris) was investigated. A hight astaxanthin yield was obtained using acetone (72.42 µg/g). Thin layer chromatographic separation of carotenoid extracts from P. longirostris yielded three distinct bands. The Rf values for the three bands were respectively 0.33, 0.60, 0.80 which corresponded to astaxanthin, astaxanthin monoester and astaxanthin diester. The antioxidant activities of astaxanthin at different concentrations were evaluated using various in vitro antioxidant assays, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, reducing power, β-carotene bleaching and DNA nicking assays. Interestingly, astaxanthin extract showed strong antioxidant activity. The radical scavenging activities and reducing powers of astaxanthin were close to and even better than those of the synthetic antioxidant BHA. The astaxanthin extract from shrimp shell waste exhibited high inhibition of β-carotene bleaching and also showed a well DNA protection against degradation by hydroxyl radicals. The anti-proliferative activity of the astaxanthin extract was also investigated. The inhibition concentration (CI50) of proliferation of tumor cells of human laryngeal carcinoma (Hep 2 cells) was 300 µg astaxanthin /ml.

The large production of sulfated polysaccharides was routinely investigated by various procedures such as enzymatic method and acid hydrolysis. The free-radical depolymerization applied directly on the skin of ray constitutes an efficient method and an original process to produce bioactive compounds in large amount and good reproducibility. The depolymerized sulfated polysaccharides fractions obtained from the skin of ray Raja montagui have an average molecular weight ranging from 29 kDa to 5 kDa and were endowed with higher anticoagulant activity compared to mammalian dermatan sulfate from intestinal mucosa. Moreover, the anticoagulant effect of these fractions was 4 and 5-fold higher than the DS from porcine mucosa as shown by activated partial thromboplastin time and thrombin time, respectively. In particular, this was illustrated by lower IC50 as for the overall inhibition of thrombin in human plasma.

Unlike classical digestive lipolytic enzymes, the marine snail digestive lipase (mSDL) and marine snail digestive phospholipase A2 (mSDPLA2) showed maximal activities at a high temperature (50°C) and at pH 8.5. Both lipase and phospholipase A2 activities were remained stable in the presence of organic solvents. Phospholipase activity was calcium dependent, since no significant activities were detected in the presence of ion chelators like EDTA. Nevertheless, Mg2+, Mn2+ and Cu2+ inhibited the phospholipase activity. Otherwise, Hg2+ and Cu2+ ions act as strong inhibitors of mSDL activity when using tributyrin as a substrate. The digestive phospholipase cleaved efficiently fatty acids from phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylserine. Stability of lipase and phospholipase in the presence of organic solvents, as well as at high temperatures, makes them good candidates for application in non-aqueous catalysis.

Skins, scales and bones are the major by-products of the fish-processing industry. These by-products are not regarded as ordinary saleable products and are usually discarded causing a heavy environmental impact. However, marine by-products are a good source of collagen that could be extracted and further enzymatically hydrolyzed to liberate interesting bioactive peptides. Collagen-derived peptides may exhibit interesting antioxidant activity, potent antihypertensive activity, antimicrobial activity against different strains of bacteria, protective effect on cartilage, capacity to stimulate bone formation, and also other interesting activities (e.g., satiety, calciotropic, or opioid). The bioactive properties of collagen-derived peptides, and also their resistance to protein digestion, make them potential ingredients of health promoting foods.

Enzymatic hydrolysis of proteins from marine resources could be produced for uses like functional ingredients in a wide and always increasing zone of application in different food products. The objective of this study was to examine the effects of enzymatic hydrolysis on the interfacial and surface properties of cuttlefish (Sepia officinalis) muscle proteins. Two microbial enzymes (Alcalase® 2.4 L and Bacillus licheniformis NH1 proteases) were used for preparation of cuttlefish muscle protein hydrolysates (CMPHs). The enzymatic hydrolysate obtained through the addition of Alcalase® reached the maximum nitrogen recovery (63%) at DH = 12.5%, water holding capacity (WHC) of 2.78 ml water/g CMPH, 1.84 ml oil/ g CMPH of fat absorption at DH = 7.6%. On the other hand, the hydrolysate obtained with NH1 proteases attained 68% of nitrogen recovery at DH = 15%, 3.2 ml water/g CMPH and 2.15 ml oil/g CMPH for the holding capacity and fat adsorption, respectively, at DH = 5.5%. In addition, the interfacial (emulsion activity index, emulsion stability index) and the surface (foaming capacity and foaming stability) properties decreased with the increase of the DH. At the same time of hydrolysis, the functionalities of protein hydrolysate depended on the enzyme used. In general, these results indicate the potential utilization of CMPHs in food formulations for the direct human consumption.

In order to utilize some fish by-products, which are normally discarded as industrial waste in the process of fish manufacture, digestive amylases of barbel (Barbus callensis), grey triggerfish (Balistes capriscus) and sardinelle (Sardinella aurita) were extracted, characterized and used for specific oligosaccharides generation. Starch zymography study shows that the crude amylase extract of Sardinelle contained at least two clear zones, however grey triggerfish and barbel extracts contained at least one amylolytic activity. The α-amylase activities of viscera extract of barbel and grey triggerfish were highly active between pH 5.0 and 9.0 with an optimum around pH 8.0. However, the activity of sardinelle fish viscera shows two optima pH at 6.0 and 8.0. The optimum temperature for amylolytic activity was 40 °C for sardinelle and grey triggerfish viscera amylase and 50 °C for barbel viscera amylase. The main hydrolysis products of potato starch by the studied amylases were maltose and glucose. Therefore, these enzymes could be considered as a potential candidate for use in the production of syrups rich with glucose and maltose.

A collection of both commercial and non-commercial galloyl derivatives (either isolated from plants or synthesized) was examined for an in vitro structure-activity relationship (SAR) screening of their anti-yeast activity. Most of the compounds exhibited an antimycotic activity when used together with amphotericin B (AMB) and none when used alone. The SAR study indicated the presence of two galloyl moieties in adjacent position as an important structural characteristic. In fact, among the compounds tested, 2,3-O-digalloyl-O-methylglucose and 2,3-O-digalloyl-Omethylmannose exhibited a synergistic interaction with AMB against a set of Candida albicans, Candida glabrata and Pichia kudriavzevii strains. A similar biological activity has also been observed for epigallocatechin gallate (EGCG). The high structural similarity between the two digalloyl derivatives and EGCG was advocated as possible rationale to explain their synergy with AMB.

The current paper reviews the published literature up to March 2012 regarding the phytochemical components and biological activities of Verbesina species (Asteraceae). A compilation of compounds isolated from several members of this genus is presented. Eudesmanes are the most common secondary metabolites found within this genus. Flavonoids, guanidine alkaloids, acetylenic compounds, and several other terpenes with a great variety of hydrocarbon skeletons have also been isolated. The botanical classification, ethnopharmacology and pharmacological applications of Verbesina species are discussed.

Separation and retention of both polar and nonpolar compounds by the same stationary phase can be a useful approach for analyses of complex samples. Biological samples encompass a broad range of polarities and varied chemical properties. A gradient elution run with acetonitrile-water as the mobile phase was used for the separation of polar and non polar compounds from Aphanothece halophytica using ODS C18 column with photo diode array detection. The various fractions collected were identified through Electrospray ionisation-mass spectrometry (ESI-MS) and Nuclear Magnetic Resonance (NMR) analyses. The High Performance Liquid Chromatography (HPLC) method provided good baseline separation of all the compounds in 15 min without the need for sample derivatization. Retrospective review of ESI-MS and NMR data identified the major compounds as nostocyclamide, trimethylglycine, phosphatidyl glycerol.