Abstract:
In this study, the UV absorbing properties of extracts of Canna flowers
were evaluated using spectroscopic techniques and Mansur equation. The
methanol and methanol: distilled water (1:1) extracts of red and yellow
Canna flowers were analyzed for their SPF (Sun Protection Factor) by
measuring UV absorbance of different concentrations in methanol.
Dermatone® was used as a reference agent. Absorption data were obtained
in the range of 290-320 nm, at every 5 nm and the SPF values were
determines. All the extracts showed substantial UV absorbing abilities in
the UVB region. The methanolic extract of Canna red flowers (0.8 mg mL-
1) has the highest mean SPF value 24.34 ± 0.02. All concentration series
(0.2, 0.4, 0.6, 0.8 and 1.0 mg mL-1) of Canna red flowers have SPF ≥ 6.
Phytochemical screening of crude methanolic extract of Canna red flowers
revealed the presence of diterphenes, alkaloids, flavonoids, phenols and
glycosides. These components were separated by Preparative Thin Layer
Chromatography (PTLC). Flavonoid fraction from PTLC showed the
highest mean SPF value of 13.66 ±0.05, while diterphenes, alkaloids,
phenols and glycosides have the values of 6.56 ± 0.03, 0.11 ± 0.03, 11.60 ±
0.09 and 2.60 ± 0.08 respectively. The reference agent Dermatone® had
SPF value of 25.72 ± 0.32. The results of this study indicate that the
methanolic extract of Canna red flowers absorb the UVB radiation and
possess sun protection ability against UVB radiation. The active
components responsible for UV absorption could be isolated and used in
sunscreen formulations.
