Chemical composition and biological potency of the marine red algae Laurencia filiformis, Laurencia intricata, Plocamium brasiliense and Ochtodes secundiramea of the Brazilian coast

Author(s)

Vanessa Gressler

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
• Defense date: 2010-09-08

Examining board members

Ernani Pinto; Mutue Toyota Fujii; Elizabeth de Souza Nascimento; Lydia Fumiko Yamaguchi; Maurício Yonamine

• Advisor: Ernani Pinto

Abstract

The ocean provides large diversity of species, among them the seaweeds, which are mainly used as food, industrial products and as medicine. Considering the biodiversity, there are only few studies which analize the algae volatile compounds and their biological activity. So that, this work describes specially compounds from the primary metabolism (lipids, proteins and amino acids), chemical volatile composition, and antioxidant and antimicrobial potencies of four red algae of the Brazilian coast (Laurencia filiformis, Laurencia intricata, Plicamium brasiliense and Ochtodes secundiramea). The lipid analysis showed that these algae have ω3 and ω6 polyunsaturated fatty acids, but the palmitic acid is the most abundant. The protein content observed is considerable and approximately 50% of the amino acid composition is of essential amino acids. To extract the volatile organic compounds from the algae selected for this study, three methods were used: hydrodestilation, solvent extraction and HS-SPME. For chemical characterization of the volatile compounds, the technique used was gas chromatography coupled with mass spectrometry (GC-MS). In addition, the two most abundant compounds from the essential oil of L. filiformis, the (-)-7-epi-silphiperfolan-6β-ol and the (-)-silphiperfolan-7β-ol, and four compounds of the aceton/water extract of P. brasiliense the 3,4-erythro-7-dichloromethyl-3-methyl-3,4,8-trichloro-1,5(E),7(E)-octatriene; the 3,4-erythro-7-dichloromethyl-3-methyl-3,4,8-trichloro-1,5(E),7(Z)-octatriene; the 3,4-erythro-1-bromo-7-dichloromethyl-3-methyl-3,4,8-trichloro-1(E),5(E),7(E)-octatriene and the 3,4-erythro-1-bromo-7-dichloromethyl-3-methyl-3,4,8-trichloro-1(E),5(E),7(Z)-octatriene, were isolated and identified using different chromatographic techniques like preparative TLC and HPLC for isolation and spectroscopic (NMR uni and bidimensional) and spectrometric techniques (HRMS and EIMS) for analysis. The antioxidant activity of the essential oils, of the extracts and of the isolated compounds was verified by two methods (DPPH and chemiluminescence). The dichloromethane extracts of L. filiformis (IC50 of 48.5 µg/mL) and L. intricata (IC50 de 58.0 µg/mL) showed higher potency. The same samples do not have antimicrobial activity in concentrations until 500 µg/mL up against the nine microorganisms tested. (AU)

• FAPESP's process: 06/06412-5 - Composition and biological activity of volatile compounds of red algae from the Brazilian coast (Rhodophyta)
• Grantee: Vanessa Gressler
• Support Opportunities: Scholarships in Brazil - Doctorate