The distribution of macronutrients, anti-nutrients and essential elements in nettles, Laportea peduncularis susp. peduncularis (River nettle) and Urtica dioica (Stinging nettle)

Alpine Diet in Valmalenco (Lombardy, Italy): Nutritional Features of Spontaneous Plants and Traditional Dishes

BACKGROUND

Along the Alps, the Alpine diet is considered to be one of the most common nutritional models. Next to traditional animal-based products, spontaneous plants of the territory are collected and eaten.

AIM

The aim of this study is to evaluate the nutritional features of selected autochthonous plants of the territory and the typical recipe of green gnocchi.

METHODS

The analyses of proximate composition, carotenoid, total phenol, and mineral contents in raw and cooked plant samples and the chemical composition and in vitro starch digestibility in green and control gnocchi were performed.

RESULTS

Except for Aruncus dioicus, all the wild plants contained high levels of carotenoids (15-20 mg/100 g FW), mainly as xanthophylls. Rumex acetosa showed the highest levels of total phenols (554 mg GAE/100 g FW), and Urtica dioica can be considered to be a good dietary source of iron, calcium, and magnesium (4.9, 410, and 72 mg/100 g FW). Cooking significantly decreased the potassium and magnesium contents in all wild species, and total phenols and carotenoids in Aruncus dioicus, Blitum bonus-henricus, and Silene vulgaris (p < 0.05). The slowly digestible fraction of starch (%SDS/available starch), which is inversely correlated to insulin demand, was significantly increased in green gnocchi compared to matched control gnocchi (p < 0.05).

CONCLUSIONS

Traditional consumption of spontaneous plants in the Alpine regions might increase the dietary intakes of several bioactive substances and contribute to cover the nutritional needs of micronutrients.

Elemental analysis of soils along the South African National Road (N3) - a combined approach including statistics, pollution indicators, and geographic information system (GIS)

The South African National Road (N3) in the KwaZulu-Natal province is one of the major transportation routes from the Durban harbor. In this study, metal concentrations in Bidens pilosa L., which grows alongside the N3, and soil were determined using inductively coupled plasma - optical emission spectrometry to evaluate the impact of soil quality on the uptake. Furthermore, the distribution of Pb and Cd was mapped using the geographic information system (GIS) approach to identify the potential benefits of spatial data applications in soil studies. Plant concentrations of toxic metals, especially Pb, were high and were linked to high soil concentrations. The target hazard quotients indicated a low risk of adverse effects due to Cd exposure and increased risk due to As and Pb exposure. The carcinogenic risk was high for As and Cd exposure at all sites and Pb at 40% of the sites. Soil quality indicators (geoaccumulation indices and enrichment factors) showed soils to be moderate to heavily contaminated. Principal component analysis indicated different anthropogenic sources of contamination, including vehicular emissions and a combination of industrial, agricultural, and social impacts. Kriging interpolation depicted the spatial diffusion of Cd and Pb concentrations throughout the study area with different hot-spot areas of metal contamination for these two metals. The study demonstrated that the plants growing along national roads are not suitable for human consumption.

Determination of heavy metals in selected fish species and seawater from the South Durban Industrial Basin, KwaZulu-Natal, South Africa

The South Durban Industrial Basin (SDIB), South Africa, an economic hub that spans a long coastline, is a disaster management hotspot, which threatens the sustainability of the fishing industry in this region. This study investigated the elemental concentrations in fish and seawater from a mini-ecosystem in the SDIB, to determine if a direct relationship exists between these two matrices, and to assess for metal toxicities. The results showed As and Cr to be above the maximum permissible limits (MPLs) of the World Health Organization (WHO) for all fish species (blacktail, karanteen, five finger, mullet, and pompano), while fish from Isipingo Beach exceeded the WHO MPLs for Pb, As, and Cr. Fish did not display signs of metal toxicity indicating either a harmless form of metals or high tolerance levels. Typical concentrations of metals in seawater (mg L^-1) at (Isipingo Beach, Cuttings Beach, and Amanzimtoti Beach) were found to be for Al (3, 2.7, and 16.4), As (0.17, 0.11, and 0.19), Cr (0.16, 0.17, and 0.23), Cu (0.15, 0.13, and 0.24), Fe (2.7, 3.45, and 33.9), and Zn (2, 2.1, and 2.12). Except for As, estimated daily intakes, target hazard quotients, and carcinogenic risks indicated no associated health risks due to consumption of the fish from the SDIB. However, due to target hazard quotients and carcinogenic risks for As being above 4 and 0.0001, respectively, fish from the SDIB should be consumed in moderation or not consumed to prevent long-term toxic effects of As.

Elemental Distribution and Health Risk Assessment of the Edible Fruits of Two Ficus Species, Ficus sycomorus L. and Ficus burtt-davyi Hutch

Edible fruits of two indigenous medicinal Ficus species (Ficus sycomorus L. and Ficus burtt-davyi Hutch) collected from eight different sites in South Africa were assessed for nutritional value, elemental concentration, and the possible risk associated with their consumption. The metal concentrations in the fruits and growth soil were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The results showed elemental concentrations in the fruits to contribute significantly to recommended dietary allowances and were found to be in decreasing order of Ca > Mg > Fe > Zn > Mn > Cu > Cr and Ca ˃ Mg ˃ Fe ˃ Mn ˃ Zn ˃ Cu for both F. sycomorus and F. burtt-davyi fruits. The results for proximate composition of F. sycomorus fruits were (in %) 55.8 for moisture, 25.3 for carbohydrates, 5.6 for protein, 8.9 for fats, 55.8 for crude fiber, and 4.4 for ash; for F. burtt-davyi fruits, it was (in %) 78.9 for carbohydrates, 5.0 for protein, 8.4 for lipids, 4.0 for crude fiber, and 3.7 for ash. The health risk assessment showed target hazard quotient, and hazard indices for all the studied heavy metals in the fruits for all the sites were to be less than one and the target carcinogenic risk values to be within the acceptable regulatory cancer risk range. This study confirms that the fruits of F. sycomorus and F. burtt-davyi are safe for human consumption due to low non-carcinogenic and carcinogenic adverse health effects.

Chemical and elemental analysis of the edible fruit of five Carpobrotus species from South Africa: assessment of nutritional value and potential metal toxicity

Edible wild fruits of five Carpobrotus species (C. acinaciformis, C. deliciosus, C. dimidiatus, C. edulis subspecies edulis and C. mellei) were assessed for their nutritional value by determining the proximate chemical composition. Fruits were high in moisture (77.6% to 90.3%), carbohydrates (58.8% to 70.3%) and energy (1240 to 1370 kJ 100 g^-1), with adequate amounts of protein (8.1% to 26.0%) and low in lipids (0.9% to 2.4%). Elemental concentrations were in decreasing order of Ca > Mg > Fe > Mn > Zn ~ Cu > Cr > Se ~ Ni ~ Co. Most fruits were rich in Cr (contributing between 30% and 143% towards its RDA) and C. delicious and C. mellei being rich in Mn, contributing 49 to 156% towards its RDA. Except for C. dimidiatus, toxicity studies revealed all species to contain low levels of toxic metals (As, Cd and Pb) making them suitable for human consumption.

Nutritional value, antioxidant and antidiabetic properties of nettles (Laportea alatipes and Obetia tenax)

Nettles are commonly consumed in South Africa, Europe and Asia and are used in traditional medicine to treat a variety of ailments. In this study, the nutritional value of the leaves of nettles (Laportea alatipes and Obetia tenax) was evaluated and compared, when cooked and uncooked. The results showed a decrease in the concentrations of crude protein, vitamin A, vitamin E and metals after cooking of nettles. Although cooking reduced the concentrations of essential elements in nettles, their contribution to the diet remained adequate. L. alatipes presented with reduced levels of Cd (from 1.86 to 0.810 mg kg^-1) and Pb (from 2.87 to 1.88 mg kg^-1) after cooking. Similarly, Cd (from 2.97 to 0.780 mg kg^-1) and Pb (from 2.21 to 0.795 mg kg^-1) levels in O. tenax decreased after cooking, demonstrating the significance of cooking. The antioxidant activity of the nettles was determined using the 2,2-diphenyl-l-picrylhydrazyl (DPPH) free radical and ferric reducing antioxidant power (FRAP) assays. The methanol extract of Obetia tenax showed high ferric reducing power whilst the radical scavenging activity was due to the presence of the bioactive molecule, β-carotene, in the plants which exhibited higher DPPH radical scavenging ability relative to test samples and standards. The in vitro antidiabetic activity of the extracts and compounds from the nettles was better than or comparable to that of the known standard, acarbose, which underscores the prospective antidiabetic properties of nettles. Overall, our study provides scientific validation for the ethno-medicinal use of nettles and supports their consumption, which highlights their potential as nutraceuticals.

Carotenoids, tocopherols, organic acids, charbohydrate and mineral content in different medicinal plant extracts

Nettle (Urtica dioica L.), tansy (Tanacetum vulgare L.), bladder campion (Silene vulgaris (Moench) Garcke, waterpepper (Polygonum hydropiper L.), common centaury (Centaurium erythraea Pers.) and rose hip fruit (Rosa canina L. cv. Plovdiv 1) were used for preparation of different water extracts (infusion, decoction and microwave extract) and ethanol (tincture) extracts. Carotenoids (lutein, lycopene and β-carotene), tocopherols (α-, γ- and δ-), organic acids (ascorbic, malic, fumaric and citric), five macro- and three microelements, sugars and uronic acids content in the obtained extracts were analyzed. Among the investigated plants, stinging nettle, bladder campion and rose hip fruit were evaluated as most potential with respect to bioactive compounds and microelements. The results showed that the selected six medicinal plants and their extracts can be presented as sources of dietary fibers and micronutrients, which may encourage further application as food supplements and beverages as well as to motivate plant use as a dietary alternative in different foods. The present study is a first detailed analysis with respect to sugar content of decoction, infusion and tincture of S. vulgaris.

Elemental distribution in the edible leaves of Celosia trigyna from the western and northern regions of Nigeria

Celosia trigyna, which belongs to the plant family Amaranthaceae, is a plant used in traditional medicine to treat several conditions such as sores, chest pains, diarrhoea and menstrual cramps in many countries in Africa. It is also consumed by the local people in Nigeria as soups, sauces and stews. In this study, the distribution and bioaccumulation of the elements in C. trigyna species and growth soil from the western and northern regions of Nigeria was investigated to determine the effects of geographical location on the uptake of elements by the plant. Elemental concentrations in the leaves from the western region were found to be in decreasing order of Ca > Mg > Fe > Mn > Zn > Cu > Pb > As > Ni. Concentrations of elements in the leaves from the northern region were found to be in decreasing order of Ca > Mg > Fe > Mn > Zn >  Cu > As > Pb > Ni > Co > Cd. Proximate analysis of leaves from both regions compared well with the recommended dietary allowance making the leaves safe for human consumption. Principal component analysis was used to group elements having the same sources irrespective of their geographical locations. Cd, Co and Cr were not detected in the leaves from the western region. Concentrations of As and Pb were above maximum permissible limits in both regions, while Ayegunle and Bida (in the northern region) had the highest concentrations of Cd. The high level of these toxic metals may be attributed to anthropogenic activities. It is therefore important that the Nigerian agricultural extension system emphasizes the dangers of heavy metal contamination in leafy vegetables to farmers. Activities of the manufacturing industries in the study area should be adequately monitored under standard environmental protection laws.

Elemental analysis and nutritional value of edible Trifolium (clover) species

Trifolium species, commonly known as clover species, have a cosmopolitan distribution and, as such, are used in many different traditional systems of medicine and consumed by many communities all over the world. In this study, the elemental distribution and nutritional value of five edible Trifolium species, namely, Trifolium africanum, Trifolium burchellianum, Trifolium repens, Trifolium dubium and Trifolium pratense were investigated to evaluate the potential of these plant species to alleviate malnutrition, thereby contributing toward the fight against food insecurity. Trifolium species were found to be a rich alternate source of essential nutrients with concentrations of elements being in decreasing order of Ca > Mg > Fe > Mn > Zn > Se > Cu > Cr > Pb > Ni > Co > Cd > As and with adequate levels of lipids (4.2 to 8.6%), proteins (35.1 to 45.4%) and carbohydrates (26.7 to 47.0%). Trifolium species were found to be rich in Se (contributing greater than 516% toward its RDA) with T. dubium having a concentration of 0.53 mg 10 g^-1, dry mass, which is higher than Brazil nuts. T. pratense was found to be the most suitable species for human consumption due to it having low levels of toxic metals (As, Cd and Pb) while being rich in macro- and micro-elements, especially Fe (7.84 mg 10 g^-1, dry mass) and Se (0.36 mg 10 g^-1, dry mass).