Current Advances on the Extraction and Identification of Bioactive Components of Sage (Salvia spp.)

Common sage (Salvia spp., with the most common species Salvia officinalis L., Lamiaceae) is an important medicinal and aromatic plant, with antioxidant, antimicrobial, anti-inflammatory and anticancer properties. The polyphenolic compounds are mainly responsible for its diverse biological activity. Many different methods for extraction and identification of sage bioactive compounds, using various solvents, have been developed in recent years. The total phenolic content is usually measured and identified by various technical methodologies with different sensitivity and specificity. In this aspect, the present review is aimed to critically summarize and discuss various technical approaches for the extraction and identification of sage bioactive components in order to point out the more appropriate approaches of them.

Lignocellulosic Biomass as Source for Lignin-Based Environmentally Benign Antioxidants

Antioxidant activity is an essential aspect of oxygen-sensitive merchandise and goods, such as food and corresponding packaging, cosmetics, and biomedicine. Technical lignin has not yet been applied as a natural antioxidant, mainly due to the complex heterogeneous structure and polydispersity of lignin. This report presents antioxidant capacity studies completed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The influence of purification on lignin structure and activity was investigated. The purification procedure showed that double-fold selective extraction is the most efficient (confirmed by ultraviolet-visible (UV/Vis), Fourier transform infrared (FTIR), heteronuclear single quantum coherence (HSQC) and 31P nuclear magnetic resonance spectroscopy, size exclusion chromatography, and X-ray diffraction), resulting in fractions of very narrow polydispersity (3.2⁻1.6), up to four distinct absorption bands in UV/Vis spectroscopy. Due to differential scanning calorimetry measurements, the glass transition temperature increased from 123 to 185 °C for the purest fraction. Antioxidant capacity is discussed regarding the biomass source, pulping process, and degree of purification. Lignin obtained from industrial black liquor are compared with beech wood samples: antioxidant activity (DPPH inhibition) of kraft lignin fractions were 62⁻68%, whereas beech and spruce/pine-mixed lignin showed values of 42% and 64%, respectively. Total phenol content (TPC) of the isolated kraft lignin fractions varied between 26 and 35%, whereas beech and spruce/pine lignin were 33% and 34%, respectively. Storage decreased the TPC values but increased the DPPH inhibition.