Antibiotic degradation and mineralization: efficiency increase on combining different chemical treatment processes.

The goal of this study was to assess the efficiency of antibiotic degradation applying different chemical treatment methods and their combinations. Thus, improvement in the efficiency of these methods when combined was quantified. The methods tested to degrade/mineralize the antibiotics amoxicillin (AMX) and ciprofloxacin (CIP) under different pH conditions (4, 7 and 10) were ultra-violet irradiation (UV254 nm), ultrasound (US), hydrogen peroxide (H2O2) and ozone (O3) alone and in combination. The results showed that individual methods were only partially efficient in the degradation/mineralization of antibiotics, except for ozonation at alkaline pH. In the combined methods, the best performance was obtained with US/UV/H2O2/O3 (pH 10, 20-min treatment), where the degradation rates for the antibiotics were 99.8% for CIP and 99.9% for AMX. For the mineralization efficiency the values obtained were 71.3% for CIP and 79.2% for AMX. The results of this study could contribute to the development and improvement of wastewater treatment aimed at avoiding the presence of residual antibiotics in the environment.

Seasonal variation of gastroprotective terpenoids in Maytenus robusta (Celastraceae) quantified by gas chromatography-flame ionization detection (GC-FID).

The triterpenes friedelin (1), ß-friedelinol (2) and 3,15-dioxo-21α-hydroxyfriedelane (3) in the aerial parts of Maytenus robusta, a Brazilian medicinal plant with antiulcer potential, were seasonally quantified by gas chromatography flame-ionization detection (GC-FID) using an external standard. The method was found to be linear, precise and sensitive. Compounds 1 and 2 were found in M. robusta leaves and branches, with highest concentrations in the leaves collected in autumn, i.e. 3.21 ± 0.16 and 12.60 ± 1.49 mg g-1 dry weight of 1 and 2, respectively. On the other hand, compound 3 was found only in the branches, with the highest concentrations in winter and autumn (0.21 ± 0.01 and 0.20 ± 0.02 mg g-1). The results allow to define the optimal season and plant parts for the collection of M. robusta as a phytotherapeutic drug.