To study the phytochemical composition of Siphonochalina siphonella
sponge from the
western coast of the Red Sea and to evaluate the isolates for possible in vitro cytotoxic, antibacterial
and antiviral activities.
The compounds obtained were isolated and purified by different chromatographic means.
Their structures were established by means of spectral analysis including 1D 1
H and 13
C and 2D
correlation nuclear magnetic resonance (NMR) and high resolution mass spectroscopy (HR-MS).
Crystal violet staining method (CVS) was used for the assessment of the cytotoxic activity against
HepG-2 and MCF-7 human cell lines, while agar-well diffusion method was employed to measure
antimicrobial activity against two Gram-positive and two Gram-negative bacteria. The antiviral activity
was determined by the inhibition of cytopathic effect (CPE) in susceptible mammalian cells.
Four triterpenes, possessing two different skeletons, were isolated and identified as
sipholenone A, sipholenol A, neviotine A and sipholenol L. All four compounds were significantly
cytotoxic to MCF-7 and HepG-2 cancer cell lines (p < 0.05) in a concentration-dependent manner with
(the inhibitory concentration required to reduce cell survival by 50 %) in range 2.8 - 19.2 μg/mL.
The highest antibacterial activity was observed for neviotine A (Compound 3) against Bacillis subtilis
(17.2 ± 0.58). On the other hand, all the compounds showed moderate to weak anti-viral activity.
The findings reveal the strong cytotoxic activity of all the isolated triterpenes from the Red
Sea Sponge, S. siphonella
. Sipholenone A (Compound 1) displayed significant cytotoxic activity towards
MCF-7 and HepG-2 cancer cell lines with IC50
= 3.0 and 2.8 μM, respectively.