Phenolic constituents and antioxidant activity of Euphorbia retusa Forssk.

The aim of the present study was to evaluate the phenolic contents in capsule and root methanolic extracts of Euphorbia retusa followed by identification of phenolic on capsule extracts through high-performance liquid chromatography (HPLC- DAD) for the first time. Likewise, the antioxidant activity of both extracts was investigated by using Cupric reducing antioxidant capacity (CUPRAC). The result implies that E. retusa capsules have the highest phenolic and flavonoid contents with 105.33 ± 7.75 µg GAE.mg-1 extract 19.95 ± 0.96 µg QEs.mg-1 extract; respectively and the highest activity in CUPRAC assay with epigallocatechin 3-O-Gallate was the major flavonoid. Thus, our findings indicate that E. restusa capsules may be valorized in industrial fields.

Entomofauna of Ziban oasis, Biskra, Algeria.

An inventory was carried out at five stations in the oasis of Ziban, an oasis that is characterized by its high-quality dates, in order to study the relationships between the oasis ecosystem and its insect fauna. Specimens were sampled using pitfall traps containing ethylene glycol as a preservative. In total, 115 arthropod species were collected during 5 months of survey. These species belonged to 61 families, 17 orders, and 4 classes (12 orders from Insecta, 3 from Arachnida, 1 from Chilopoda, and 1 from Malocostraca). The most represented insect orders were Coleoptera (44.42%), Hymenoptera (20.86%), and Lepidoptera (7.87%). Represented in the collections were phytophagous, omnivorous, and predator/parasite species. Given the large number of species collected, and the largely unknown relationships existing between the various ecological groups, this study is a first step in the description of the oasis entomofauna.

Evaluation of antioxidant activities of the edible and medicinal Acacia albida organs related to phenolic compounds.

This study compared phenolic contents and antioxidant activity in different organs of Acacia albida (leaves and bark) and focuses on identification of phenolic compounds of leaves by HPLC-DAD. The analysed organs exhibited differences in total polyphenol contents (100 and 59.5 mg GAE g(-1) DW). Phenolic contents of leaves were two times higher than those in bark. Ethanolic extracts exhibited good antioxidant activities with IC50 = 26 µg mL(-1) for DPPH and EC50 = 50 µg mL(-1) for FRAP. Identification by HPLC-DAD revealed the presence of nine phenolic compounds known for their high antioxidant activity. The results suggested that this species can be used as source of natural antioxidants.

Intervessel connectivity and relationship with patterns of lateral water exchange within and between xylem sectors in seven xeric shrubs from the great Sahara desert.

The main objective of this study was to evaluate the role of intervessel contacts in determining the patterns of hydraulic integration both within and between xylem sectors. The degree of intervessel contacts and the lateral exchange capability within and between sectors were examined and correlated in different xeric shrubs. A dye injection method was used to detect the connections between vessels; an apoplastic dye was sucked through a known number of vessels and its distribution in the xylem network was followed. Hydraulic techniques were used to measure axial and tangential conductivity both within and between xylem sectors. The intra- and inter-sector integration indexes were then determined as the ratio of tangential to axial conductance. Species differed significantly in the degree of intervessel contacts, intra- and inter-sector integration index. In all cases, hydraulic integration was observed to be higher within sector than between sectors. From the correlation analyses, the intervessel contacts showed a very weak relationship with inter-sector integration index and a strong positive relationship with intra-sector integration index. Results suggested that (1) the factors affecting patterns of lateral flow within xylem sectors might be relatively different from those between sectors. (2) The degree of intervessel contacts was a major determinant of hydraulic integration within the same xylem sector. (3) Intervessel connectivity alone was a poor predictor of hydraulic integration between different sectors, implying a significant contribution of other anatomical, physiological and environmental factors in determining the patterns of integrated-sectored transport within woody stems.