Regresar

Chemical composition and biotoxicity of red algae Kappaphycus alvarezii Doty (Solieriaceae)

Abstract:

A phytochemical and bioactivity study was carried out on the chloroform, ethyl acetate and methanol extracts of the Kappaphycus alvarezii Doty algae (collected on  the  Island  of  Cubagua,  Venezuela).  The  LC50  values  obtained  in  the  bioassay performed with all the extracts, showed toxicity to crustacean larvae Artemia salina (LC50 <300  μg.ml-1).  By  means  of  column  chromatography  and  preparative  thin  layer,  the extracts  were  continuously  fractionated  with  chloroform  and  ethyl  acetate,  some  sub- fractions  obtained  by  GC-MS  were  analyzed,  and  some  of  their  constituents  were identified by their fragmentation patterns and comparison of their mass spectra with the existing in the database. Finding that fraction A2 from the ethyl acetate extract showed hexadecanoic  acid,  dibutyl  phthalate  and  the  steroidal  compound  cholestane  as  major components;  in  addition  to  2,6-diter-butylcyclohexa-2,5-diene-1,4-dione,  6,10,14- trimethyl-2-pentadecanone,  2-  phenylacetic  acid  and  1-  (1-propoxy)  propane  as  minor components. While the FD fraction of the chloroform extract exhibited saturated palmitic, stearic  and  myristic  fatty  acids  as  abundant  components,  and  3-ethyl-4-methyl-1H- pyrrole-2,5-dione  in  smaller  proportion.  Octadecanoic  acid  was  identified  in  the  EM7 fraction  from  the  methanolic  extract  through  uni  and  two-dimensional  NMR.  1- phenylbutan-1-ol  was  characterized  by  the  same  spectroscopic  technique  in  the  FG fraction of the chloroform extract. The different secondary metabolites identified are the first  report  for  K.  alvarezii  and  are  possibly  responsible  for  the  in  vitro  bioactivity observed.  It  can  be  inferred  that  this  red  algae  is  a  promising  source  of  bioactive compounds.  