Marco Pellizzoni

Phytochemical constituents and in vitro radical scavenging activity of different Aloe species.

The phytochemical profile of Aloe barbadensis Mill. and Aloe arborescens Mill. was investigated using colorimetric assays, triple quadrupole and time-of-flight mass spectrometry, focusing on phenolic secondary metabolites in the different leaf portions. Hydroxycinnamic acids, several characteristic anthrones and chromones, the phenolic dimer feralolide and flavonoids such as flavones and isoflavones were identified. The stable radical DPPH test and the ORAC assay were then used to determine the in vitro radical scavenging. The outer green rind was the most active, while the inner parenchyma was much less effective. The 5-methylchromones aloesin, aloeresin A and aloesone were the most active among the pure secondary metabolites tested. The results suggest that several compounds are likely to contribute to the overall radical scavenging activity, and indicate that leaf portion must be taken into account when the plant is used for its antioxidant properties.

Rapid determination of lycopene and β-carotene in tomato by liquid chromatography electrospray tandem mass spectrometry

BACKGROUND The tomato fruit is a dietary source of carotenoids, bioactive antioxidant compounds that play an important role in the prevention of degenerative diseases. Several extraction and detection techniques regarding carotenoids in tomatoes can be found in the literature, mainly based on high-performance liquid chromatography separation and ultraviolet-visible detection. RESULTS The best extraction conditions and tandem mass spectrometry (MS) analysis were evaluated: lycopene and β-carotene were extracted in a cyclohexane/ethyl acetate mixture without the addition of antioxidants, next separated by liquid chromatography on a C(18) column and then determined through electrospray tandem MS. Ionic suppression by the matrix in negative ionisation mode did not allow the analysis of extracts, hence the positive ionisation mode was chosen. Validation parameters demonstrated the suitability for purpose of the analytical method: accuracy, precision, linearity and detection limits were adequate. The method was finally applied to different tomato samples, and differences could be easily highlighted. CONCLUSION The method was simple, fast and appropriate for the purpose of analysing lycopene and β-carotene in tomatoes.

Italian Opuntia ficus-indica Cladodes as Rich Source of Bioactive Compounds with Health-Promoting Properties

Natural by-products, especially phenolic compounds, are in great demand by the nutra-pharmaceutical and biomedical industries. An analytical study was performed to investigate, for the first time, the presence of antioxidant constituents and the corresponding in vitro antioxidant activity in the extract of cladodes from Ficodindia di San Cono (Opuntia ficus-indica) protected designation of origin (PDO). The cladode extracts were analysed for target determination of selected constituents, i.e., β-polysaccharides and total phenolic content. Moreover, the antioxidant activity of hydro-alcoholic extracts was assessed by means of two different methods: α, α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging method and ferric reducing antioxidant power (FRAP) assay. An untargeted UHPLC-ESI-QTOF-MS profiling approach was used to depict the phenolic profile of hydro-alcoholic cladode extracts. Interestingly, over 2 g/kg of polyphenols were detected in this matrix, and these compounds were mainly responsible for the antioxidant properties, as shown by the strong correlation between phenolic classes and antioxidant scores. Finally, this study provides basic information on the presence of bioactive compounds and in vitro antioxidant activities in cladode extracts from cactus that might recommend their novel applications at the industrial level in the field of nutraceutical products.

Effect of Different Aloe Fractions on the Growth of Lactic Acid Bacteria

Several foods on the market, such as yogurt and fermented milk, include mixtures of prebiotics and probiotic microorganisms effective in promoting the proliferation and equilibrium of intestinal bacteria, thus improving gut health. Particularly, researchers and the public have shown increasing interest in the combination of probiotics with natural substances that promote health or that can act as substrates to promote bacterial growth. The aim of this study is to evaluate the effects of different extracts of Aloe barbadensis and Aloe arborescens in fermented milk, taking into account both the prebiotic effect of aloe polysaccharides and the antimicrobial activity of several secondary metabolites. The results demonstrate a beneficial effect of 5% aloe inner gel on Lactobacillus growth and confirm the antimicrobial activity of the phenolic compounds peculiar of green rind extracts.

Efficacy and residues of permethrin-incorporated nets used to protect maize grains post-harvest

BACKGROUND Pest control in post-harvest food storage represents a great challenge in the sustainable prevention of food losses, and insecticide-treated netting may represent a valid alternative to traditional practices such as the direct application of insecticides. In our work, the efficacy of a permethrin-incorporated net, in combination with polypropylene or jute sacking, was tested for the control of Sitophilus oryzae. Contamination of maize grain by permethrin from the treated netting was also evaluated. RESULTS A 98% control of S. oryzae was achieved using permethrin-treated netting. Both jute and polypropylene acted as additional barriers, increasing efficacy to 100%. The results also showed the contamination of maize kernel by permethrin released from the treated netting. The concentration of residues in maize kernels increased with increasing temperature; however, use of jute or polypropylene significantly reduced (by 87% to 97%) the concentration of residues transferred to maize kernels. CONCLUSIONS Permethrin-treated netting provided a high level of efficacy in the post-harvest protection of maize. Several factors influenced permethrin residue concentrations in grains when treated nets are used. Therefore, solutions should be found to prevent contamination of food stored in the bags that are treated with insecticides.

Administration of Aloe arborescens homogenate to cattle: interaction with rumen fermentation and gut absorption of aloin

Abstract Aloe has long been used as a traditional medicine for its numerous beneficial properties, which are mainly ascribed to β-polysaccharides and phenolic compounds including anthraquinones, anthrones and chromones. However, few studies on large animals are currently available. The effect of whole leaf Aloe arborescens homogenate on the in vitro rumen fermentative processes was tested using alfalfa hay and barley meal as substrates. The Aloe homogeneate was added at three different concentrations (0.4, 2.0 and 10.0 g L−1 of fermentation liquid). The same homogenate was dosed (200 g) orally and through the rumen cannula to three rumen cannulated heifers and orally to six lactating dairy cows to measure the rumen degradation of aloin and the transfer of aloin from the gut into the blood, respectively. The Aloe homogenate did not affect in vitro rumen fermentations and feed digestibility. The administration of Aloe homogenate did not negatively affect animal feed intake and health neither on the cannulated heifers nor on the dairy cows. Aloin underwent a rapid degradation in the rumen milieu, and became undetectable 2 h after oral dosage. However, when Aloe homogenate was administered to dairy cows, aloin appeared in blood as early as 2 h after administration, reached a maximum after 4 h (6.2 ± 5.8 μg L−1) and progressively decreased thereafter. These results suggest that Aloe compounds can be absorbed into the blood and encourage the study of Aloe as a potential nutraceutical in ruminants. Further studies should determine the most effective in vivo dosage.

Use of permethrin coated nets to protect stored grain from pests infestations

Surveys carried out in some villages of Democratic Republic of the Congo showed that insect pests are a major cause of food loss for rural populations. Cereal grains are often compromised by pests in the field and during storage. Among cereals cultivated for family consumption in these areas of Africa, mainly maize and rice are both seriously infested by Coleopteran pests belonging to the genus Sitophilus. Any approach currently adopted to solve this problem, as the manual removal of visible insects, is often inadequate or insufficient. Due to the limited availability of chemical insecticides and their high price in these countries, our aim is to study a simple and cheap way to protect grain after harvest. The technology derives from anti-malaria mosquito nets, also known as insecticide treated nets or bednets, modified for the new purpose. Nets consist in fine-mesh polyester coated with permethrin (2.0%), a synthetic second generation pyrethroid that gives repellent and insecticide effect, while ensuring a high human safety. The idea is to use these nets to wrap jute bags or other containers in which grain is commonly stored in poor countries. Preliminary bioassays with adults of Sitophilus oryzae showed that knock-down values for 50 and 95% of exposed insects (KD 50 and KD 95 , respectively) were equal to 4.8 and 9.5 min. We are currently carrying out further in vivo bioassays (in Italy) and field studies (in Congo) to test the efficacy of the treated net. The coating of structures for grain preservation could be a viable sustainable strategy for limiting food losses in countries that lack resources and technologies for pest control.