Natural extracts from Pterospartum tridentatum at different vegetative stages: ...

• Autor(es): Coelho, M.T. ; Pimenta, C. ; Gonçalves, J.C. ; Alves, V. ; Martins, M.M.
• Data: 2012
• Identificador Persistente: http://hdl.handle.net/10400.11/2022
• Origem: Repositório Científico do Instituto Politécnico de Castelo Branco
• Assunto(s): Pterospartum tridentatum; Aqueous extracts; Extraction yields; Antioxidant activity; Phenolic content
• Tipo de Documento: Documento de conferência
• Idioma: Inglês

Descrição

The aerial parts of Pterospartum tridentatum, a wild growing species in Portugal used in traditional medicine and gastronomy, were harvested at different stages (vegetative phase, flowering phase and beginning of dormancy) in two locations in Portugal (Malcata and Gardunha mountains), and the respective aqueous extracts have been studied. The influence of the seasonal variation in the extraction yield, total phenolic content and antioxidant activity was evaluated. The extraction was carried out in boiling water in consecutive steps. After each step, the aqueous extract was separated and fresh water was added maintaining the same plant material. The procedure was repeated seven times, within an overall time period of 180 minutes. Higher extraction yields were achieved with plant stems collected at the vegetative phases, either from Malcata or Gardunha regions. The total phenolic content of the extracts from Malcata plants ranged from 273 mg to 400 mg gallic acid equivalent/g dry matter, which was quite similar to that determined for extracts from Gardunha (245 to 394 mg gallic acid equivalent/g dry matter). The antioxidant activity was determined by the radical scavenging activity method using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The greatest radical scavenging activity was observed in the flowers extracts, even though all extracts produced presented a good antioxidant activity. Furthermore, the antioxidant activity was not affected by the exposure of the plant material at 100ºC for long periods of time (180 min). The results show that Pterospartum tridentatum has a great potential to be used as a new source of natural antioxidants for the food industry.