Optimization of MAE for the Separation of Nicotine and Phenolics from Tobacco Waste by Using the Response Surface Methodology Approach

This study intends to valorize by-products of the industrial processing of tobacco to obtain nicotine and phenolics as value-added compounds. Three influential parameters of the microwave-assisted extraction-MAE (temperature, treatment time, and solvent/solid ratio) were studied for the optimization of the extraction protocol for tobacco leaves and three types of waste-scrap, dust, and midrib, respectively. Nicotine was the dominant bioactive compound in all extracts, ranging from 1.512 to 5.480% in leaves, 1.886 to 3.709% in scrap, 2.628 to 4.840% dust, and 0.867 to 1.783% in midrib extracts. Five phenolic compounds were identified and quantified, predominated by chlorogenic acid and rutin. Additionally, total phenol content and antioxidant activity were determined using spectrophotometric assays. Optimization was performed in two aspects: to obtain a maximum extraction yield with minimum nicotine content and to obtain a maximum extraction yield with maximum nicotine content. These findings demonstrate that tobacco waste is a valuable source of bioactive compounds and MAE can be a promising alternative technique to obtain extracts rich in targeted bioactive compounds, especially nicotine.

Helichrysum italicum (Roth) G. Don subsp. italicum from Herzegovina

The chemical composition of essential oils isolated from immortelle (Helicrysum italicum subsp. italicum) collected in Herzegovina during five different periods, was investigated by GC/MS analysis. The main compounds were a-pinene (15.7 %) and γ-curcumene (12.8 %), followed by 4,6,9-trimethyldec-8-en-3,5-dione (8.7 %), neryl acetate (6.9 %), limonene (6.4 %) and β-selinene (5.3 %). In total, 69 components were identified whose share changed over the vegetative cycle. Antioxidant activity of methanolic extracts of immortelle were determined according to DPPH (IC50 = 23–34 μg/mL) and FRAP (29 μg/mL is equivalent to 1.1‒2.2 mM Fe2+) methods. Acetylcholinesterase inhibitory potential, investigated by modified Ellman’s assay and determined as IC50 values, were 340–440 μg/mL for methanol extracts and 135 μg/mL for essential oil. Metanolic extracts showed strong antioxidant activity and potential to inhibit AChE. Essential oil possesses complex chemical composition, inhibition activity of AChE and weak antioxidant capacity.