341 Photoprotective Effects of Carotenoid
effectively prevent aging of the skin, and it can also prevent sunburn by functioning as an
antioxidant and a UV absorber.
Cytotoxicity studies of carotenoid extract on HaCaT cell line. The safety of carotenoid extract
was evaluated by testing it on HaCaT as a model system. HaCaT cells were treated with
different concentrations of carotenoid extract for 24 and 48 hours. As shown in Figure 4A,
Figure 2. (A) Calibration curve of ascorbic acid for DPPH assay. (B) DPPH RSA of the carotenoid extract.
Figure 3. Calibration curve of ascorbic acid for FRAP assay.

342 JOURNAL OF COSMETIC SCIENCE
no cytotoxicity was evident in HaCaT cells with increasing concentrations of the carotenoid
extract at 24 hours. To understand the effect of prolonged exposure of the carotenoid extract
to skin cells, HaCaT cells were treated with the respective concentration for 48 hours. No
cytotoxicity was observed on HaCaT cells after 48 hours (Figure 4B), which suggests that
the carotenoid extract would be safe for topical use.
In silico ADMET prediction. The ADMET attributes for the major carotenoid (1’OH-4-
keto-ϒ-carotene) of R kroppenstedtii are depicted in Table II. The important toxicological
properties—such as mutagenicity (determined by the Ames test), carcinogenicity, and acute
oral toxicity—were predicted among others using ADMETlab 2.0. The results suggest
Figure 4. (A) Cell-based cytotoxicity assay to determine the effect of carotenoid extract on HaCaT cell line at
24 hours. C is control (no carotenoid extract), V is vehicle control (DMSO). (B) Cell-based cytotoxicity assay to
determine the effect of carotenoid extract on HaCaT cell line at 48 hours. C is control (no carotenoid extract),
V is vehicle control (DMSO).
Table II
ADMET Profile of 1’OH-4-Keto-ϒ-Carotene
Property Value Comment
hERG blockers 0.01 Category 0 inactive
H-HT (human hepatotoxicity) 0.109 Category 0 H-HT negative
DILI (drug induced liver injury) 0.043 Category 0 no risk of DILI
Ames toxicity 0.09 Category 0 Ames negative
Rat oral acute toxicity 0.089 Category 0 Low toxicity
Carcinogenicity 0.196 Category 0 Noncarcinogen
Eye corrosion 0.003 Category 0 Noncorrosive
Skin sensitization 0.624 May cause mild sensitization