Calendula officinalis,a Mediterranean native
annual herb has been used in folk medicine since an ancient time. An in-vitro
study was performed with novel extracts from C. officinalis dry flower head which were extracted in ethanol
based solvent and different natural solvents. Cytotoxicity test of solvents and
C. officinalis extracts was conducted
with different doses using MTT assay. Genotoxicity and anti-genotoxic ability
of one of the natural solvent based extract was investigated using CBMN assay. HaCat
keratinocytes cell line was used as an in-vitro cell model for 4, 24 and 48
hour incubation. After pre-incubation of HaCat cells with C. officinalis extract, reactive oxygen species (ROS) were
generated by co-incubation with H2O2. None of the
solvents or C. officinalis extracts were
significantly cytotoxic to the HaCat cells. In the in-vitro protection assays,
the ethanol based C. officinalis
extract, extract E6, showed time dependent protection against the cell killing
effect of H2O2: E6 displayed protection ability at 24
hour pre-incubation which reached a significant level at 48 hour
pre-incubation. One of the natural solvent based C. officinalis extract, extract E3, displayed dose and time
dependent protection against cytotoxic damage of H2O2, however,
it did not reach statistical significance. Pilot genotoxic study for the 24 and
48 hour demonstrated that extract E3 was not genotoxic. Instead, it showed
anti-genotoxic ability by lowering the number of micronuclei (MNi) per 1000
binucleated cells (BNs) produced by H2O2 challenge.
Present study indicates that even though the natural solvent based extract did
not provide significant protection against cytotoxic damage by ROS, it provides
a clear evidence of strong anti-genotoxic property of extract E3 against
chromosomal damage by ROS. Therefore these natural solvent based extracts could
be an industrially important anti-genotoxic products or a cosmetic formulation
with therapeutic value.