Search

Wood waste from forestry practices offers an inexpensive source of biomass that can be converted into bioenergy, fuels and value-added chemicals. Balsam fir (Abies balsamea (L.) Mill.) bark offers a source of bioactive natural products, such as lignans, separated through solvent extraction (SE). The objectives of the research were: (1) to compare traditional solvent with supercritical fluid extraction (SFE) and slow pyrolysis processes to separate and convert chemicals from the bark and (2) to assess the biological activity of the extracts and pyrolysis oils. In vitro biochemical assays were used to measure antioxidant and oxygen radical-scavenging abilities, and glutathione S-transferase and esterase enzyme inhibition. The pyrolysis oil had similar anti-oxidant, radical-scavenging ability and enzyme inhibitory activity to the SE and SFE extracts. Fractionation and mass spectrometry identified catechol and p-coumaryl alcohol in the organic phase of pyrolysis oil. The small phenolic compounds identified offer starting materials for pharmaceutical or insecticide synergist application.

Black nightshade (Solanum nigrum, S. nigrum L.) and red nightshade ( Solanum villosum, S. villosum Mill.) are medicinal plants from the Solanaceae family that synthesize glycoalkaloids and other secondary metabolites. To recognize the potential insecticide activity of these compounds, leaf extracts (containing glycoalkaloid and methanol fractions) were tested for enzyme inhibition, antifeedant activity and toxicity. For in-vitro glutathione S-transferase (GST) inhibition activity, we used insecticide-resistant Colorado potato beetle, Leptinotarsa decemlineata ( L. decemlineata; Say) midgut and fat-body homogenate. In-vivo toxicity and the antifeedant activity were performed using larval bioassays. The methanol extracts had greater GST inhibitory activity compared to the glycoalkaloids, as well as greater 2nd instar larvae mortality and antifeedant activity. Furthermore, the green leaf volatile compound, cis-hex-3-enyl acetate, at the concentration of 5 ppm, caused 50% mortality of 2nd instar larvae. Our findings suggest the potential usefulness of S. nigrum and S. villosum extracts to control L. decemlineata.

In this study, we set out to investigate the effect of sodium chloride (NaCl) on carotenoid and flavonoid production by the black nightshade (Solanum nigrum L.). The study was carried out under green chamber conditions using seedlings subjected to 0, 50, 100 and 150 mM NaCl for 3 weeks. The negative effect of NaCl on dry biomass production of roots and leaves were accompanied by a significant restriction in K+, Ca2+ and Mg2+ ion uptake and by an increase in Na+ ion concentrations, the effects of which were most pronounced at the highest NaCl level. Salt stress also induced oxidative stress, according to the amplified levels of thiobarbituric acid reactive substances and relative ion leakage ratio. Expression of some related carotenoid (phytoene synthase 2 and β-lycopene cyclase) and flavonoids genes (phenylalanine ammonialyase, chalcone synthase and flavonol synthase) were induced by NaCl, followed enhanced production of β-carotene, lutein, and quercetin 3-β-d-glucoside. At the highest NaCl level (150 mM NaCl), quercetin 3-β-d-glucoside synthesis came at the expense of reduced β-carotene and lutein, while salt stress treatment affected leaf antioxidant activities to a great extent relative to the control. Our data suggest that the potential antioxidant properties of carotenoids and flavonoids and their related key genes may be efficiently involved in the restriction of salt-induced oxidative damages.