Effect of drying methods on chemical composition and antioxidant activity of underutilized stinging nettle leaves

Assessment of antioxidant and antibacterial efficacy of some indigenous vegetables consumed by the Manipuri community in Sylhet, Bangladesh

The rapid dietary changes experienced by indigenous people worldwide threaten the use of traditional foods, which are often undervalued. This study focused on evaluating the antioxidant and antibacterial efficacy of five vegetables typically consumed by the Manipuri ethnic groups in the Sylhet region of Bangladesh: Yongchak seed (Parkia speciosa), Telikadam seed (Leucaena leucocephala), Phakphai leaf (Persicaria odorata), Sheuli leaf (Nyctanthes arbor-tristis), and bamboo shoot (Bambusa spp.). The samples were dried and powdered to assess the antioxidant activity through total phenolic content (TPC), total flavonoid content (TFC), total tannin content (TTC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Antibacterial efficacy was determined by measuring the zone of inhibition (ZOI), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). Leafy vegetables exhibited higher TPC, TFC, and TTC than seeds and shoots, with N. arbor-tristis leaf showing the highest TPC (99.16 ± 2.07 mg GAE/g DW) and P. odorata leaf exhibiting the highest TFC (9.19 ± 0.7 mg QE/g) and TTC (3.59 ± 0.26 mg TAE/g). However, Bambusa spp. shoot extract showed the highest antioxidant potential (IC50: 1.66 ± 0.05 mg/mL). All samples exhibited higher ZOI against gram-positive bacteria (Bacillus spp. and Staphylococcus spp.), ranging from 10 ± 2.65 to 19.33 ± 2.08 mm. L. leucocephala seed extract showed the highest antibacterial activity against both the tested gram-positive bacteria with a MIC of 15.6 mg/mL. Conversely, the P. odorata leaf extract exerted the strongest antibacterial effect against gram-negative bacteria, with the lowest MIC values for Klebsiella spp. (31.25 mg/mL) and Escheria coli (62.5 mg/mL). The findings of this investigation suggest that the selected indigenous vegetables could be valuable sources of phytochemicals with potential antioxidant and antibacterial activities. Incorporating and promoting these traditional foods into the diet may improve food security, dietary diversity, and public health in Bangladesh.

Synergistic effect of drying methods and ultrasonication on natural deep eutectic solvent extraction of phytochemicals from African spinach (Amaranthus hybridus) stem

The study evaluated the combined effects of drying methods (air drying [AD], hot AD [HAD], microwave drying [MD], and freeze-drying [FD]) and ultrasonication parameters (sonication temperature [STemp]: 40, 50, and 60°C) and heating time (STime: 60 and 120 min) on natural deep eutectic solvent (NADES) extraction of phytochemicals from Amaranthus hybridus stem. Increasing the STemp increased the extraction yield (ECY) of the phytochemicals for all drying methods but increase in the heating time reduced the ECY slightly. MD combined with 60°C ST showed the highest ECY (53%), whereas HAD combined with 40°C ST had the lowest ECY (18%). At 60 min heating time, increasing the ST from 40 to 50°C increased the total phenolic content (TPC) in the extract for most drying methods except MD, and a sonication time of 120 min showed a slightly higher TPC, especially for MD samples. At 60 min sonication, total flavonoid content (TFC, 800 mgQE/g) was highest for AD plus 50°C ST and lowest for AD combined with 60°C (100 mgQE/g), whereas for 120 min sonication, MD and AD with 50°C showed the highest TFC (690 mgQE/g). FD retained better some of the vitamins (thiamine, riboflavin, niacin) but MD retained better vitamin C. The antioxidant capacity was not so much different among the drying methods except for FD, which showed lower values. These results provide a theoretical basis for the synergistic applications of drying and ultrasonication during NADES extraction of phytochemicals from Amaranthus hybridus.

Exploring the synergistic potential of wild nettle and olive oil: bioactive compounds, antioxidant capacity, and antibacterial properties

This study delved into the incorporation of wild nettle (Urtica dioica L.) leaves powder with virgin olive oil, exploring its potential to enhance nutritional value and health benefits. The antioxidant, antibacterial, and mineral-enrichment attributes of the resultant nettle-infused olive oil were investigated. Phenolic composition analysis revealed that an optimal maceration time of 30-40 minutes leads to maximal phenolic and flavonoid contents (57.66 mg GAE/100 g and 67.18 mg QE/100 g, respectively). The infused oil demonstrated superior radical scavenging activity (DPPH and ABTS assays) compared to virgin olive oil. Notably, nettle infusion significantly elevates zinc (10.12 mg/kg) and iron (13.85 mg/kg) contents. Antibacterial assays exhibited enhanced inhibition diameters and lower MIC and MBC values for nettle-infused oil against various bacterial strains. The study's findings underscore the potential of nettle infusion to enhance the nutritional and functional attributes of olive oil, holding promise for novel culinary and health applications.

Boosting nutritional quality of Urtica dioica L. to resist climate change

Introduction

More than ever, traditional agricultural practices need a shift towards more resilient, sustainable, modern and adaptable practices that benefit the health of the planet and people. Today's consumers are constantly on the lookout for novel, highly nutritious foods that have a positive impact on their overall health and well-being. Nettle (Urtica dioica L.) is gaining recognition not only as a popular medicinal plant, but also as a desirable green leafy vegetable rich in phytonutrients. As it is difficult and even expensive to control the quality standards of wild-collected plants, the implementation of sustainable cultivation methods, especially hydroponics, with effective greenhouse management could be a possible solution to obtain a standardized product with high nutritional value. Therefore, the aim of this study was to investigate the effects of four nutrient solutions differing in the content of macro- and micronutrients (especially nitrogen, potassium, calcium, magnesium and iron) and two consecutive cuts on the number of leaves, yield, nitrate and mineral content and the content of specialized metabolites of stinging nettle from a floating hydroponic system.

Methods

Nettle plants were cultivated in a hydroponic system using the floating hydroponics technique. The two-factorial experiment was performed with nutrient solution and consecutive cuts as factors.

Results

The highest yield (2.49 kg/m2) was achieved after the 1st cut with plants cultivated in the nutrient solution with higher nutrient concentration. All tested nutrient solutions resulted in high levels of minerals and bioactive compounds in the plant material (ascorbic acid content of 102.30 mg/100 g fw and total phenolics content of 465.92 mg GAE/100 g fw), confirming floating hydroponics as a sustainable approach for cultivating nettle with enhanced nutritional value and antioxidant potential.

Conclusion

It is important to highlight that the nutrient solution with the lowest nutrient composition yielded the highest concentrations of calcium (5.54%) and iron (180.67 mg/kg dw). Furthermore, it exhibited elevated levels of specific phenolic compounds, including caffeoylmaleic acid, ellagic acid, ferulic acid, naringin, and rutin trihydrate. Notably, this solution demonstrated the lowest nitrate content (4225.33 mg/kg fw) in the plant material. Therefore, it can be recommended as a preferable formulation for hydroponic nettle cultivation.

Analysis of Genes Associated with Feeding Preference and Detoxification in Various Developmental Stages of Aglais urticae

Herbivorous insects and host plants have developed a close and complex relationship over a long period of co-evolution. Some plants provide nutrients for insects, but plants' secondary metabolites also influence their growth and development. Urtica cannabina roots and leaves are poisonous, yet Aglais urticae larvae feed on them, so we aimed to clarify the mechanism enabling this interaction. At present, studies on the detoxification mechanism of the A. urticae are rare. In our study, first, we used the A. urticae larval odor selection behavior bioassay and choice feeding preference assay to analyze the feeding preferences of A. urticae on its host plant, U. cannabina. Next, we used transcriptome sequencing to obtain the unigenes annotated and classified by various databases, such as KEGG and GO. In this study, we found that U. cannabina could attract A. urticae larvae to feed via scent, and the feeding preference assay confirmed that larvae preferred U. cannabina leaves over three other plants: Cirsium japonicum, Cannabis sativa, and Arctium lappa. The activity of detoxifying enzymes GST and CarE changed in larvae that had consumed U. cannabina. Furthermore, through transcriptomic sequencing analysis, 77,624 unigenes were assembled from raw reads. The numbers of differentially expressed genes were calculated using pairwise comparisons of all life stages; the expression of detoxification enzyme genes was substantially higher in larvae than in the pupal and adult stages. Finally, we identified and summarized 34 genes associated with detoxification enzymes, such as UDP-glucose 4-epimerase gene, 5 Glutathione S-transferase genes, 4 Carboxylesterase genes, 4 Cytochrome P450 genes, 10 ATP-binding cassette genes, 4 Superoxide dismutase, and Peroxidase. Moreover, we identified 28 genes associated with the development of A. urticae. The qRT-PCR results were nearly consistent with the transcriptomic data, showing an increased expression level of four genes in larvae. Taken together, this study examines the correlation between A. urticae and host plants U. cannabina, uncovering a pronounced preference for A. urticae larvae toward host plants. Consistent with RNA-seq, we investigated the mechanism of A. urticae's interaction with host plants and identified detoxification-related genes. The present study provides theoretical support for studying insect adaptation mechanisms and biological control.

How to Increase the Nutritional Quality of Stinging Nettle Through Controlled Plant Nutrition§

Research background

As food production faces major challenges, modern agricultural practices are increasingly focused on conserving resources, reducing negative environmental impacts and sustainably producing food with a high content of health-promoting phytochemicals. During production, many factors can affect the quality and chemical composition of a final food product. Proper selection of cultivating conditions, especially a balanced nutrition, can significantly increase nutritional value and result in foods with strong biological and functional properties. Stinging nettle is a rich source of minerals, vitamins, pigments, phenols and other bioactive compounds and can be consumed as a green leafy vegetable with beneficial effects on human health. Therefore, the aim of this study is to determine the nutritional quality and antioxidant capacity of stinging nettle leaves under the influence of different nutrient solution (NS) treatments and three harvest cycles.

Experimental approach

The experiment was conducted in a floating hydroponic system in which treatments with different nutrient solutions were applied and three harvest cycles were carried out. After each harvest, the following treatments were applied: treatment 1 - depletion of nutrient solution by adding water, treatment 2 - supplementation of nutrient solution by adding initial nutrient solution and treatment 3 - correction of nutrient solution by adding nutrients. Among the bioactive compounds, minerals, ascorbic acid, phenols and photosynthetic pigments content, as well as antioxidant capacity were analysed spectrophotometrically, while individual phenols were determined by liquid chromatography.

Results and conclusions

Different nutrition solution treatments and the number of harvest cycles had a significant effect on the content of the analysed bioactive compounds. The highest mass fraction (on fresh mass basis) of total phenols expressed as gallic acid equivalents (377.04 mg/100 g), total flavonoids expressed as catechol equivalents (279.54 mg/100 g), ascorbic acid (112.37 mg/100 g) and pigments (total chlorophylls 1.84, and total carotenoids 0.36 mg/g) as well as the highest antioxidant capacity expressed as Trolox equivalents (35.47 µmol/g) were recorded in the samples supplemented with nutrient solution (treatment NS2) and analysed after the third harvest.

Novelty and scientific contribution

This is the first time that stinging nettle leaves have been produced in a floating hydroponic system by controlled plant nutrition. We have set this type of nutritional manipulation with multiple harvest cycles as an innovative technique for the production of novel food with improved nutritional value that can be consumed as green leafy vegetables.

Impact of Drying Process on the Phenolic Profile and Antioxidant Capacity of Raw and Boiled Leaves and Inflorescences of Chenopodium berlandieri ssp. berlandieri

C. berlandieri ssp. berlandieri (C. berlandieri) is one of the most common members of the group of plants known as quelites, which are dark leafy greens widely consumed in Mexico. This study aimed to evaluate the impact of two drying procedures (oven drying and freeze-drying/lyophilization) on the polyphenolic composition, antioxidant capacity, and proximal chemical analysis of C. berlandieri leaves and inflorescences (raw or boiled). The results indicated that the raw freeze-dried samples had higher amounts (p < 0.05) of total phenolic compounds, total flavonoids, and antioxidant capacity, mainly in the inflorescence. The oven-dried samples showed an increased concentration of polyphenols after boiling, while the lyophilized samples showed a slightly decreased concentration. The drying process was observed to have little impact on the proximal chemical composition. Quantification by UPLC-DAD-ESI-QToF/MS identified up to 23 individual phenolic compounds, with freeze-dried samples showing higher amounts of individual compounds compared with oven-dried. Procyanidin B2 was found exclusively in the inflorescences. The inflorescences have a higher content of phenolic compounds and greater antioxidant capacity than the leaves. Regardless of the drying process, the leaves and inflorescences of C. berlandieri contain an interesting variety of phenolic compounds that may have beneficial effects on health.

Characteristics of wood apple (Limonia acidissima L.) and soybean powder jelly for emergency food alternatives

The substitution of wood apple juice and soybean powder in the seaweed jelly product can be used as an alternative to emergency supplementary feeding (ESF) for children under five years of age, which contains high protein, fiber, and calories. This study aimed to determine the effect of adding wood apple juice and soybean powder to the nutrition content, vitamin C, zinc, magnesium, total phenol, antioxidant activity, acceptability, and shelf-life of seaweed jelly products. This study was an experimental study with a completely randomized design with two treatment factors, which consisted of making seaweed jelly products with three different ratios of wood apple juice and soybean powder, 60:40 (F1), 50:50 (F2), and 40:60 (F3), dried at 40 °C (T1) and 50 °C (T2). Macronutrients were determined using proximate analysis. The total phenol and vitamin C were measured using Folin-ciocalteu reagent and UV-Vis spectrophotometry. Antioxidant activity was analyzed by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH). The contents of zinc and magnesium were evaluated through Atomic Absorption Spectrophotometry (AAS). Estimation of shelf life was determined with Accelerated Shelf-Life Test (ASLT) method and Arrhenius equation model. The best formula based on proximate analysis was F3, which contained 361.98 kcal of energy and 33.79 g of protein. The best formula (F1) dried at 40 °C; contains 56.28 mg/100 g vitamin C; zinc was 1.55 mg/100 g; magnesium was 79.25 mg/100 g; antioxidant activity (IC50) was 88.39 μg/mL; and total phenol was 8.59 mg GAE/g. The quality attributes of the best formula show the potential of the jelly as an emergency food despite its short shelf-life.

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.

Optimization of Extraction Parameters and Characterization of Tunisian Date Extract: A Scientific Approach Toward Their Utilization

The response surface methodology (RSM) was used in order to select the extraction conditions of extract from Kentichi date powder; a by-product of the date-processing process. Powder/solvent ratio, extraction temperature, and extraction time all had an impact on sugar yield, and these model factors have quadratic effects influencing sugar yield. Optimal extraction was obtained with 300 g/L powder/solvent ratio, 32.7 °C extraction temperature, and 2.1 h extraction time. Under these conditions, Kentichi date powder's (KDP) sugar yield was 77.1%, which was close to the predicted value of the model (80.50%). The results of Kentichi date powder extract (KDPE) showed that the total sugar content is 160.09 g/L. However, the protein content is 10.31 g/L with a majority of the essential amino acids (essentially glutamic acid (28.39 mg/L) and aspartic acid (9.65 mg/L)). The determination of antioxidant activity of KDPE showed a high activity (DPPH IC₅₀ = 4.8 mg/mL, ABTS IC₅₀ = 3 mg/mL, FRAP = 4.70 μmol AAE/mL and, TAA = 18.04 μmol Fe(II)/mL). The results show also that the freeze-drying technique has a lot of potential for producing powder from KDPE with many desirable properties. The findings indicate that KDPE with a high nutritional value could be used as a component for the formulation of functional foods.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12355-022-01223-2.

Appraisal of the Antioxidant Activity, Polyphenolic Content, and Characterization of Selected Himalayan Herbs: Anti-Proliferative Potential in HepG2 Cells

Natural antioxidants derived from plants have played a vital role in preventing a wide range of human chronic conditions and provide novel bioactive leads for investigators in pharmacotherapy discovery. This work was designed to examine the ethnopharmacological role of Urtica dioica (UD), Capsella bursa-pastoris (CBP), and Inula racemosa (IR). The total phenolic and flavonoid contents (TPC and TFC) were illustrated through colorimetric assays, while the antioxidant activity was investigated through DPPH and ABTS assays. The evaluation of phytochemicals by FT-IR of UD and CBP revealed high contents of aliphatic amines, while IR showed a major peak for ketones. The antioxidant activity, TPC and TFC were highest in the ethanol extract of UD, followed by CBP, and IR showed the lowest activity. All of the extracts revealed significant antioxidant capacities along a dosage gradient. Through a HPLC analysis at a wavelength of 280 nm, UD leaves demonstrated an intense peak of quercetin, and the peak for rutin was less intense. CBP (whole plant), instead, demonstrated a major yield of rutin, and a peak for quercetin was not observed in CBP. IR (rhizomes) showed both quercetin and rutin. All of the extracts were significantly cytotoxic to HepG2 cells after 48 h with the trend IR > UD > CBP. The outcomes of this study may be effective in the selection of specific plants as realistic sources of the bioactive components that might be useful in the nutraceutical progression and other biomedical efficacies.

Dehydration and Rehydration Kinetics Modeling in the Phytochemical, Aroma, and Antioxidant Capacity of Tree Tomato Fruit Dried with Microwaves and Freeze Driers: A Comparative Study

In the present study, we investigated and compared the effect of microwaves and freeze-drying methods on the dehydration and rehydration kinetics in the phenolic, anthocyanin, aroma profiles, and antioxidant properties of tree tomato fruit (Solanum betaceum). The tree tomatoes were dried using microwaves at 350 W, 500 W, and 650 W, and then freeze-dried. The obtained drying curves were processed to find the most suitable mathematical modeling among the different moisture ratio expressions. Total phenolics, total anthocyanins, total flavonoids total carotenoids, vitamin C, Ferric Reducing Antioxidant Power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) were tested. Using High performance Liquid Chromatography (HPLC), phenolic and anthocyanin compound profiles were identified. The aroma profile was analyzed using gas chromatography-MS. The Midilli model, among others, precisely describes the dehydration methodology of all used drying methods with the coefficient of determination R2 = 0.99. On the other hand, the Weibull model precisely describes the rehydration process of the used drying methods (R2 = 0.99). Physical changes (color, shrinkage) were also studied. The freeze-dried tree tomatoes had a high number of phenolic compounds with 3.94 ± 0.26 mg GAE/g and total carotenoid compounds with 0.48 ± 0.04 µg/g. Epicathechin was the most abundant compound among the tested phenolics, followed by Cathechin. The Pelargonidin-3-glucoside was the most abundant anthocyanin whereas in freeze-dried tree tomatoes, 1.22 ± 0.01 mg/g. Fifty-four aroma compounds were detected and quantified. Among others, Eucalyptol was one of the most abundant aroma compounds analyzed in dried tree tomato fruit. Freeze-dried tree tomatoes retained most of the antioxidant and flavor compounds analyzed.

Extraction of nettle (Urtica dioica L.) toxins under natural biting conditions

A group of natural poisons from various animals, plants and microorganic sources can be extracted, produced and processed. Following ten years of field and laboratory research and studies, resulted from the creation of the first live collection of Iranian nettle ecotypes (LCINs) at the University of Zanjan, the feasibility of fresh and live extraction of nettle poison in pristine and untouched conditions was examined. In this study, the ability of tree tissues to absorb, hunt and sink nettle hairs, including styrofoam, nanofabric and sponge of the same length (15 cm) and same diameter (4 cm) having the same size of pores, was studied in four selected nettle ecotypes, including ecotypes of Mashhad, Mazandaran, Gilan and Zanjan provinces, Iran. For all four ecotypes on the three studied surfaces, the mean number of fully stuck and sunken needles, broken and sunken needles on the surface tissue, pores torn by plant needles and pores containing pale green liquid were counted and fully scrutinized. The results showed that sponges can be a suitable texture for hunting nettle hairs for extracting fresh and raw live venom of approximately 5 ml on a sponge source for 5 min. Based on GCMS analysis of total venom extraction resulting profile from the studied protocols had more than 10 compounds including some important sulfur containing such as: 2,2-dimethyl-propyl 2,2-dimethylpropanesulfinyl sulfone and 2-ethylthiolane, S,S-dioxide, etc. In this method, there is no need to remove the plant and stem. Its unique advantage is in continuous poison harvests during the 6-month growing season. Based on published research, this is the first report of live extraction of nettle medicinal poison.

Biomimetic Synthesis of Silver Nanoparticles Using Ethyl Acetate Extract of Urtica diocia Leaves; Characterizations and Emerging Antimicrobial Activity

The current work reports the biosynthesis of silver nanoparticles (AgNPs) using the antimicrobial activities of ethyl acetate extract of Urtica diocia (UD) leaves as a reducing and capping agent. The synthesized UD-AgNPs were characterized using UV−visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDAX), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and dynamic light scattering (DLS). The UD-AgNPs were evaluated against Gram-positive and Gram-negative bacteria, and their size, shape, and distribution were recorded. The average size of an NP was 19.401 nm. The zone of inhibition (ZOI) for 75 µL of UD-AgNPs against Pseudomonas aeruginosa (P. aeruginosa) was 21 ± 0.4 mm more than that of the control drug Ciprofloxacin (16 ± 10 mm). The minimum inhibitory concentration (MIC) was the lowest against Escherichia coli (E. coli) (36 ± 3 µg/mL) and Staphylococcusepidermidis (S. epidermidis) (38 ± 3 µg/mL). Moreover, the minimum bactericidal concentration (MBC) was the lowest against E.coli (75 ± 00 µg/mL) and Enterococcus faecalis (E. faecalis (83 ± 16 µg/mL). Thus, the UD-AgNPs synthesized using the ethyl acetate extract of UD can be used as a new antimicrobial drug.

Nettle Cultivation Practices-From Open Field to Modern Hydroponics: A Case Study of Specialized Metabolites

Conventional agricultural production faces numerous challenges due to the pronounced effects of climate change, particularly global warming, and drought more than ever before in history, with the primary concern being to produce adequate yields and high-quality, nutritious plant material. Likewise, people are increasingly looking for new sources of food and are becoming aware of the importance of a varied diet and its connection to health. In this sense, stinging nettle (Urtica dioica L.) stands out as a valuable species that is neglected as a food source, as it has a significant content of specialized metabolites, and thus has an extremely high potential for use both nutritionally and pharmacologically, but is still traditionally collected from natural habitats, so it can be of questionable quality and undefined chemical composition. Therefore, sustainable agricultural practices are increasingly shifting to modern hydroponic cultivation methods in greenhouses. The advantage lies in the easier management and control of a number of factors during cultivation (air temperature and relative humidity, balanced and rational fertilization, minimization of nitrate uptake, etc.), ensuring better conditions for the growth and development of nettle according to its needs. The aim of this review is to give an overview of the technology of stinging nettle cultivation in the field and to show the possibilities of cultivation with modern hydroponic techniques to obtain a final product of consistent and uniform quality, high content of specialized metabolites and significant nutritional value. Research on this topic is still sparse but will certainly increase in the future. Therefore, this review provides all the necessary data for such future studies.

Hyperthyroidism treatment by alternative therapies based on cupping and dietary-herbal supplementation: a case report

OBJECTIVES

Hyperthyroidism is characterized by increasing production of thyroid hormone (TH) and decreasing of thyroid stimulation hormone (TSH) secretion. The treatment of hyperthyroidism includes such as anti-thyroid drugs, radioiodine, and thyroidectomy have many side effects without complete curing results. We described a successful treatment of hyperthyroidism patient with dietary-herbal supplementation with wet cupping without any medicine.

CASE PRESENTATION

A 29-years female, blood analysis showed that she had low TSH (0.012 mlU/mL), and normal levels of T3 and T4. After completing 16 weeks on Carbimazole, TSH value still low (0.024 mlU/mL) and urticaria was appeared. She decided to stop Carbimazole and try alternative therapy choices. She received wet cupping and dietary-herbal supplementations (including royal jelly, green barley grass and Taraxaf^®) for two months. Notably, TSH values was increased during-after intervention and urticaria was disappeared.

CONCLUSIONS

Alternative therapy could be a beneficial choice for hyperthyroidism treatment without any side effects or complications under physician supervision.

Hyperthyroidism treatment by alternative therapies based on cupping and dietary-herbal supplementation: a case report

OBJECTIVES

Hyperthyroidism is characterized by increasing production of thyroid hormone (TH) and decreasing of thyroid stimulation hormone (TSH) secretion. The treatment of hyperthyroidism includes such as anti-thyroid drugs, radioiodine, and thyroidectomy have many side effects without complete curing results. We described a successful treatment of hyperthyroidism patient with dietary-herbal supplementation with wet cupping without any medicine.

CASE PRESENTATION

A 29-years female, blood analysis showed that she had low TSH (0.012 mlU/mL), and normal levels of T3 and T4. After completing 16 weeks on Carbimazole, TSH value still low (0.024 mlU/mL) and urticaria was appeared. She decided to stop Carbimazole and try alternative therapy choices. She received wet cupping and dietary-herbal supplementations (including royal jelly, green barley grass and Taraxaf®) for two months. Notably, TSH values was increased during-after intervention and urticaria was disappeared.

CONCLUSIONS

Alternative therapy could be a beneficial choice for hyperthyroidism treatment without any side effects or complications under physician supervision.

Influence of Different Types of Drying Methods on Color Properties, Phenolic Metabolites and Bioactivities of Pumpkin Leaves of var. Butternut squash (Cucurbita moschata Duchesne ex Poir)

Leaves of pumpkin species var. Butternut squash (Cucurbita moschata Duchesne ex Poir) is a popularly consumed leafy vegetable in the Southern African region. Traditional vegetables are commonly sun-dried as a method of postharvest preservation during the off-season. However, different drying methods affect the superior quality, functional properties, and bioactivities of the final product. Therefore, in this study, var. Butternut squash (C. moschata) underwent different drying methods, such as freeze-, oven, sun-, solar, and microwave drying to evaluate the color properties, pigments, phenolic metabolites, in vitro antioxidants, and antidiabetic activities. Results indicate that freeze-drying retained the total chlorophyll content with green color by reducing the color difference (ΔE), improved the concentration of different phenolic metabolites and the content of ascorbic acid, and enhanced the FRAP, ABTS activities and the inhibitory effects of α-glucosidase, and α-amylase. Freeze-dried leaves contained the highest concentrations of quercetin 3-glucoside 7-rhamnoside (rutin), quercetin 3-galactoside, isorhamnetin-3-galactoside-6″-rhamnoside, isorhamnetin-3-O-rutinoside compared with the leaves that underwent four other drying treatments and raw leaves. The OPLS-DA and the UPLC–QTOF/MS and chemometric approach showed that the peak at m/z 609, 1441 (quercetin 3-galactoside 7-rhamnoside) separated the freeze-dried leaves of var. Butternut squash (C. moschata) from the other four drying treatments. Therefore, freeze-drying is highly recommended to obtain good quality leaf powders that are rich in functional compounds and bioactive properties for use as functional ingredients.

Stinging Nettles as Potential Food Additive: Effect of Drying Processes on Quality Characteristics of Leaf Powders

Stinging nettle (Urtica dioica L.) is a ubiquitous, multi-utility, and under-utilized crop with potential health benefits owing to its nutritional and bioactive components. The objective of the work is to produce powders by drying wild stinging nettle leaves as a storable, low-cost functional additive to be used in bakery and ready-to-cook products. Convective drying (CD) and freeze-drying (FD) were applied on unblanched (U) or blanched (B) leaves, which were then milled to nettle powders (NPs). The obtained NPs were evaluated for selected physicochemical (moisture, color), techno-functional (flow indices, hygroscopicity), and phytochemical (pigments, phenols) characteristics as well as mineral contents. Blanching improved mass transfer and reduced the oxidative degradation of pigments during drying, but it caused a loss of total phenols content, antioxidant activity, and potassium content. As for the drying method, CD resulted in better flow properties (i.e., Carr Index and Hausner Ratio), while FD retained better the color, pigments, magnesium content, phenolic, and antioxidant parameters. Overall, the evaluated processing methods resulted in different technological properties that can allow for better evaluation of NPs as a food additive or ingredient. Among the NPs, blanched and freeze-dried powders despite showing inferior technological properties can be recommended as more suitable ingredients targeted f or food enrichment owing to better retention of bio-active components.

Influence of Harvesting Time on the Chemical Composition of Wild Stinging Nettle (Urtica dioica L.)

This research aimed to determine the effect of different harvesting times on the chemical composition of stinging nettle (Urtica dioica L.). The leaves of nettle were harvested at the same place once a month in the period of April–September 2019. The analysis focused on the contents of dry matter, soluble solids, ascorbic acid, titratable acidity, chlorophyll a and chlorophyll b, total carotenoids, total phenolic compounds, antioxidant activity, ash content, and macro- and microelements. The nettles harvested in April were characterized by the highest levels of soluble solids and some macro-and microelements (P, K, Fe, Zn). The plants harvested in May were distinguished for titratable acidity, chlorophyll a, chlorophyll b, and carotenoid contents. In this month, the plants were determined to have the highest antioxidant activity during the entire vegetation period. The plants collected in July contained the highest amount of Mn, but the antioxidant activity of these plants was the lowest during the vegetation period. In August, the plants had the highest levels of ascorbic acid, phenolic compounds, and ash, while the plants collected in September were characterized by having the highest amounts of Ca, Mg, and B as compared to those established in other months of vegetation.

Common Nettle (Urtica dioica L.) as an Active Filler of Natural Rubber Biocomposites

Common nettle (Urtíca Dióica L.), as a natural fibrous filler, may be part of the global trend of producing biocomposites with the addition of substances of plant origin. The aim of the work was to investigate and explain the effectiveness of common nettle as a source of active functional compounds for the modification of elastomer composites based on natural rubber. The conducted studies constitute a scientific novelty in the field of polymer technology, as there is no research on the physico-chemical characteristics of nettle bio-components and vulcanizates filled with them. Separation and mechanical modification of seeds, leaves, branches and roots of dried nettle were carried out. Characterization of the ground plant particles was performed using goniometric measurements (contact angle), Fourier transmission infrared spectroscopy (FTIR), themogravimetric analysis (TGA) and scanning electron microscopy (SEM). The obtained natural rubber composites with different bio-filler content were also tested in terms of rheological, static and dynamic mechanical properties, cross-linking density, color change and resistance to simulated aging processes. Composites with the addition of a filler obtained from nettle roots and stems showed the highest mechanical strength. For the sample containing leaves and branches, an increase in resistance to simulated ultraviolet and thermo-oxidative aging processes was observed. This phenomenon can be attributed to the activity of ingredients with high antioxidant potential contained in the plant.

Effect of Drying Methods on Phenolic Compounds and Antioxidant Activity of Urtica dioica L. Leaves

Stinging nettle (Urtica dioica) is a plant well known in traditional medicine for its many beneficial properties, but the lack of standardization regarding the product to offer to consumers limits its diffusion. To this end, drying appears to be a useful technique to offer a low-cost product that can be stored for long time, but the different drying procedures may give rise to end-products of very different quality as nutraceutical and antioxidant compounds. Nettle leaves have been dehydrated employing freeze-drying (FD), oven-drying (OD) or heat pump drying (HPD) and compared with fresh leaves following water extraction to emulate the use by final consumers. Results indicate that the best dehydration technique is HPD, which apparently gives rise to more than a doubling of total phenols and antioxidant activity in the extract compared to the water extract obtained from fresh leaves but a reduction in the level of ascorbic acid of about 39%. In addition, the content of some phenolic compounds is 10 to over a hundred times higher in the extract after HPD than that obtained from fresh samples. This confirms that the dehydration technique should be tuned in relation to the compounds of greatest interest or value.