Determination of antioxidant and antimutagenic activities of Phlomis armeniaca and Mentha pulegium.

This study was designed to determine antioxidant and antimutagenic activities of methanol and n-hexane extracts of Phlomis armeniaca and Mentha pulegium and their phenolic compounds. The extracts were screened for their possible antioxidant and antimutagenic activities by DPPH and ABTS free radical scavenging, reducing power, metal chelating and DNA nicking assays. The methanol extracts of the plants exhibited significant antioxidant activities determined by different assays. P. armeniaca showed higher activities in antioxidant assays. Also, the highest phenolic content was observed in P. armeniaca. In DNA nicking assay (antimutagenic), all extracts of these plants (20-40 μg/mL) exhibited DNA protecting activities. This study shows that methanol extracts of the plants have higher antioxidant activities than their hexane extract. Moreover, the plants can be used as natural antioxidants and antimutagenic sources.

Effect of 2,4-dichlorophenoxyacetic acid on growth, protein and chlorophyll-a content of Chlorella vulgaris and Spirulina platensis cells.

In this study, effect of different 2,4 -dichlorophenoxyacetic acid (2,4-D) concentrations (0.0, 9.10(-5), 9.10(-4), 9.10(-3) and 9.10(-2) mM) on growth rate, content of protein and chlorophyll-a in Chlorella vulgaris and Spirulina platensis cells was investigated. The most stimulatory effect on growth rate, protein and pigment ratio of C. vulgaris and S. platensis was observed at 9.10(-4) mM concentrations of 2,4-D. The results show that low concentrations of 2,4-D have hormonal effect due to being a synthetic auxin. Cell number protein and pigment rates were inhibited at 9.10(-2) mM concentration in C. vulgaris. Such parameters were inhibited in S. platensis, both at 9.10(-3) and 9.10(-2) mM 2,4-D concentrations. This is due to herbicidal effect of high concentrations of 2,4-D. S. platensis was found to be more sensitive than S. vulgaris to 2,4-D applications. The use of algae as bio-indicators in herbicide contaminated fresh water habitats, was discussed.

Influence of pH on lead uptake, chlorophyll and nitrogen content of Nasturtium officinale R. Br. and Mentha aquatica L.

In the present study, effects of pH (5.0, 7.0 and 9.0) and lead (1, 5, 10, 25, 50 and 100 microg mL(-1)) were investigated on uptake of lead, content of chlorophyll and nitrogen in Nasturtium officinale and Mentha aquatica. Total chlorophyll and nitrogen contents were adversely affected from Pb2+ concentrations dose dependently at each pH. The macrophytes were adversely affected by pH 5.0 or more than 9.0. After 12-days Pb2+ treatment, results showed that lead accumulation of macrophyte tissues was variable. According to the parts of the macrophytes, Pb2+ amounts were generally found at all tested pH levels and the metal concentrations for M. aquatica in the following order: root > stem > leaf and for N. officinale root > leaf > stem. Pb2+ concentrations in plant tissues (root, stem, leaf) in relation to pH were generally found for both macrophytes in following order: 7.0 > 9.0 > 5.0. Despite of the fact that high Pb2+ accumulation was observed in root tissues of the macrophytes, low metal accumulation was measured in the above-ground parts indicating low root-leaf translocation. The study indicated that uptake rate of Pb2+ and its toxicity on Chlorophyll and nitrogen contents in the macrophytes were dependent upon pH value of solutions.