HPLC-DAD identification of polyphenols from ethyl acetate extract of Amaranthus spinosus leaves and determination of their antioxidant and antinociceptive effects.[Pubmed: 29679184]

Amaranthus spinosus has been consumed traditionally to prevent various diseases including abdominal pain. In this study, the phytochemical composition, antioxidant and analgesic activities of an ethyl acetate extract of A. spinosus leaves (ASEA) were evaluated. The ASEA had the highest concentrations of total phenols (462.2 mg GAE/g DW), condensed tannin (5.01 mg CE/g DW) and total flavonoid contents (30.07 mg CE/g DW) compared to the chloroform, n-hexane, n-butanol and water extracts. Similarly, ASEA showed the most effective total antioxidant activity (45.45 µg/mL), DPPH scavenging activity (27.32 µg/mL) and hydrogen peroxide scavenging activity (30.60 µg/mL). ASEA with the doses of 200-600 mg/kg (p.o.) clearly demonstrated antinociceptive effects by reducing acetic acid-induced abdominal contortions with a maximal inhibition of 79.57% at 600 mg/kg and increasing latencies of the hot-plate paw-licking response. The tested doses also significantly (p < 0.001) decreased the reaction time in the formalin test at the neurogenic and inflammatory phases. ASEA contained ten polyphenols with caffeic acid being the predominant polyphenol. Overall, this study gave evidence that A. spinosus is a new antioxidant and analgesic agent, and justified its traditional use for the treatment of pain.

Bioaccessibility and risk assessment of essential and non-essential elements in vegetables commonly consumed in Swaziland.[Pubmed: 28647607]

The green leafy vegetables (Mormodica involucrate, Bidens pilosa and Amaranthus spinosus) are economic; seasonal; locally grown and easily available; easy to propagate and store; highly nutritious food substances that form an important component of diets. This study applies a physiology based extraction technique (PBET) to mimic digestion of these vegetables to determine the fraction of essential (Fe and Zn) and non-essential elements (Cd, Cr and Pb) that are made available for absorption after ingestion. Prior to the application of the PBET, the vegetables were cooked adopting indigenous Swazi cooking methods. Cooking mobilized most of the metals out of the vegetable mass, and the final substrate concentrations are: raw > cooked > supernatant for all the metals, and the order of average metal leaching was: Pb (82.2%) >Cr (70.6%) >Zn (67.5%) >Fe (60.2%) >Cd (53.6%). This meant that the bioavailable concentrations are significantly lower than in the original vegetable mass, if only the solid mass is consumed. Bioaccessibility was higher in the gastric tract than in the intestinal phases of the PBET for all the metals in all the vegetables. Risk assessment protocols employed on the non-essential elements (Cr, Cd and Pb) showed that the associated risks of ingesting metal contaminated vegetables are higher for children, than they are for adults, based on the target hazard quotient (THQ) index. However, the overall health risk associated with ingestion of these metals is low, for both children and adults, based on the HR index. Conclusively, this study expounds on the nutritional and risk benefits associated with ingesting naturally grown vegetables.

Seed germination in relation to the invasiveness in spiny amaranth and edible amaranth in Xishuangbanna, SW China.[Pubmed: 28414779]

Both spiny and edible amaranths (Amaranthus spinosus and A. tricolor) are exotic annuals in China that produce numerous small seeds every year. Spiny amaranth has become a successful invader and a troublesome weed in Xishuangbanna, but edible amaranth has not, although it is widely grown as a vegetable there. As seed germination is one of the most important life-stages contributing to the ability of a plant to become invasive, we conducted experiments to compare the effects of high temperature and water stress on seed germination in two varieties each of spiny amaranth and edible amaranth. Overall, the seeds of both amaranth species exhibited adaptation to high temperature and water stress, including tolerance to ground temperatures of 70°C for air-dried seeds, which is consistent with their behavior in their native ranges in the tropics. As expected, the invasive spiny amaranth seeds exhibited higher tolerance to both continuous and daily periodic high-temperature treatment at 45°C, and to imbibition-desiccation treatment, compared to edible amaranth seeds. Unexpectedly, edible amaranth seeds exhibited higher germination at extreme temperatures (10°C, 15°C, and 40°C), and at lower water potential (below -0.6 MPa). It is likely that cultivation of edible amaranth has selected seed traits that include rapid germination and germination under stressful conditions, either of which, under natural conditions, may result in the death of most germinating edible amaranth seeds and prevent them from becoming invasive weeds in Xishuangbanna. This study suggests that rapid germination and high germination under stress conditions-excellent seed traits for crops and for many invasive species-might be a disadvantage under natural conditions if these traits are asynchronous with natural local conditions that support successful germination.

Cytotoxic and apoptotic activities of extract of Amaranthus spinosus L. in Allium cepa and human erythrocytes.[Pubmed: 27896557]

The present study examined the apoptosis inducing effects of Amaranthus spinosus L. aqueous extract in Allium cepa root meristematic cells and human erythrocytes. Cytogenetic assay revealed many apoptosis inducing cytogenetic aberrations viz., cytoplasmic breakage, cytoplasmic disintegration, cytoplasmic shrinkage, receding of cytoplasm, cytoplasmic vacuolation, enucleated cell, ghost cell, nuclear vacuolation, nuclear fragmentation and nuclear disintegration. A remarkable modification of red blood cell surface morphology was observed in the result of RBC assay. The treated RBCs show membrane blebbing and shrinkage, features typical for apoptosis in nucleated cells. Significant induction of cell death was observed in treated Allium root tip cells after Evans blue staining, disclosing the membrane damage potential of the plant extract. TTC assay results in reduced mitochondrial/metabolic activity in Allium root tip cells after treatment, designating the adverse effect of plant extract on mitochondrial respiratory chain. These results confirm the apoptosis inducing potential of A. spinosus extract. Confirming the present results by further in vitro studies, it can be effectively targeted against cell proliferation during cancer treatment by inducing apoptosis. Thus from the present investigation it can be concluded that the aqueous extract of A. spinosus exhibited apoptosis induction and cytotoxic activities.