Purpose: To investigate the antimicrobial activity of crude and fractionated extracts of
Biemna tubulosa
and
Stylissa spp. thriving in Trou aux Biches lagoon, North East Mauritius.
Methods: Crude extracts (methanol: dichloromethane 1:1) and fractions of
Biemna tubulosa and
Stylissa spp (hexane, ethyl acetate and butanol) were tested against some bacterial organisms,
namely,
Escherichia coli
,
Staphylococcus aureus
and
Enterococcus faecalis
, using broth microdilution
assay. The extracts were screened for the presence of compounds that could be responsible for
bioactivity.
Results: Preliminary chemical screening revealed the presence of tannins, saponins, terpenes,
alkaloids and phenols. The hexane fraction of
Stylissa spp. and the ethyl actetate and butanol extracts
of
Biemna tubulosa were more active than the control antibiotic. Maximum antimicrobial activity was
noted for the butanol fraction of
Biemna tubulosa with minimum inhibitory concentration (MIC) of 0.091
mg/ml against
E. coli. The hexane soluble fraction of
Stylissa spp. was more active with MIC of 0.125
mg/ml against
S. aureus and
E. coli and 0.250 mg/ml against
E. faecalis.
Conclusion: The broad spectrum antibacterial activity of these sponges seemed to be due to the
presence of sesterterpenes and triterpenes, alkaloids and tannins detected in the extract fractions. This
is probably the first report on the antimicrobial activity of
Biemna tubulosa and
Stylissa spp. from
Mauritius waters.
