Impact of ultrasound-assisted extraction on quality and photostability of the Pothomorphe umbellata extracts

• Published in: Ultrasonics sonochemistry 2011-09, Vol.18 (5), p.1002-1007
• Main Authors: Costa, Fernanda Steger de Oliveira, Araújo Júnior, César Aparício de, Silva, Emmanuelle de Jesus, Bara, Maria Teresa Freitas, Lima, Eliana Martins, Valadares, Marize Campos, Marreto, Ricardo Neves
• Format: Article
• Language: English
• Subjects: 4-Nerolidylcatechol; Antioxidant activity; Chemistry; Exact sciences and technology; General and physical chemistry; Light; Photostability; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Piperaceae - chemistry; Piperaceae - radiation effects; Plant Extracts - chemistry; Plant Extracts - isolation & purification; Plant Extracts - radiation effects; Radiation Dosage; Sonication - methods; Ultrasonic chemistry; Ultrasound energy
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2011.03.016

► Ultrasound methods improved the antioxidant activity of Pothomorphe umbellata samples. ► Ultrasound extracted other active compounds and preserved their chemical integrity. ► The drug-to-solvent ratio affected the extraction yield in the ultrasound extraction. ► The ethanol concentration determined the activity of the ultrasound extracts. ► The photostability of 4-NC was lower in plant extracts than in the isolated form. Pothomorphe umbellata (L.) Miq. is a Brazilian shrub with therapeutic and economic applications. There are some reports on the technological development of P. umbellata preparations; however, there are no studies on the influence of non-conventional extraction procedures on the quality of P. umbellata extracts. The aim of this study was to evaluate the effects of the ultrasound-assisted extraction (UE) parameters upon the extraction yield (EY%) of 4-nerolidylcatechol (4-NC) and the antioxidant activity of P. umbellata extracts using a factorial design and response surface methodology. Extracts obtained by UE and percolation were compared, and the photostability of 4-NC was evaluated via the exposure of UVA and visible light to the samples. The most influential variables observed for the UE were the ethanol-to-water and drug-to-solvent ratios. UE improved the extraction kinetics of 4-NC from plant material and improved the antioxidant activity of the extracts. Some of the ultrasound extracts showed an antioxidant activity that was not proportional to their 4-NC concentration, which suggests the presence of other active antioxidant compounds in these P. umbellata extracts. There was no significant difference in the photostability of 4-NC between the percolated and ultrasound extracts. Surprisingly, the isolated 4-NC material was significantly more stable when exposed to UVA-visible light compared to 4-NC in the plant extracts.