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J. Cosmet. Sci., 74.6, 335–347 (November/December 2023)
*Address all correspondence to Madhavi R. Vernekar, madhavi.vernekar@dypatil.edu
Photoprotective Effects of Carotenoid Extracted From
Rhodococcus Kroppenstedtii
SIMRAN R. LILWANI, JYOTIRMOI G. AICH, PARVATHI J.R. AND
MADHAVI R. VERNEKAR
School of Biotechnology and Bioinformatics, D.Y. Patil Deemed to be University, Navi Mumbai,
Maharashtra, India (S.R.L., J.G.A, M.R.V.)
Somaiya Institute for Research &Consultancy, Somaiya Vidyavihar University, Vidyavihar, Mumbai,
Maharashtra, India (P.J.R.)
Accepted for publication October 02, 2023.
Synopsis
Sunscreens protect against detrimental effects of UV radiation that range from skin aging to melanoma.
With increasing awareness about the toxic effects of synthetic sunscreens, it is necessary to explore natural
sources of antioxidants and photoprotectants. Carotenoids are a class of natural pigments that have gained
considerable interest due to their antioxidant, anticancer, and anti-inflammatory properties. The present study
aims to determine the photoprotective ability of carotenoid derived from indigenously isolated Rhodococcus
kroppenstedtii in a sunscreen preparation. To ascertain the role of carotenoid extract as skin-protectant,
preformulation studies—including antioxidant assays cytotoxicity evaluation and absorption, distribution,
metabolism, excretion, and toxicity prediction—were performed. Varying concentrations (0.5−100 µM) of
carotenoid extract exhibited no cytotoxicity on the human epidermal keratinocyte cell line, suggesting the
possible use of extract as a photoprotectant. Furthermore, absorption, distribution, metabolism, excretion,
and toxicity analysis predicted the carotenoid to be noncarcinogenic and nonmutagenic. A sunscreen cream
with 10% carotenoid extract was formulated and tested for organoleptic and rheological parameters. The
tests on UV protection efficacy of sunscreen indicated its moderate broad spectrum UV protection capability
(SPF =12.75, critical wavelength =370 nm, and 3 Boots Star rating). The formulated cream displayed good
stability throughout the experimental period. Thus, the natural antioxidant sunscreen cream might be used
as a sustainable UV protection alternative.
INTRODUCTION
Sunscreens are used to safeguard the skin from the damaging effects of the sun. Broadly,
the sunscreen cream market is segmented into two product types: small molecule–
based sunscreens (also termed chemical sunscreens) and mineral or inorganic filter–
based sunscreens.1 The most commonly used sunscreens contain chemical filters such as
oxybenzone, avobenzone, octisalate, octocrylene, homosalate, octinoxate, and so forth—
these work by absorbing UV rays. According to the studies, these filters have been found in

336 JOURNAL OF COSMETIC SCIENCE
nearly all water sources around the world, impacting the aquatic food chain and contributing
to coral reef bleaching.2,3 In addition to their environmental impact, some studies suggested
that certain chemical filters could be linked to breast cancer2 and endocrine disturbances4,5
thus posing a risk to human health. Mineral sunscreens use zinc oxide or titanium dioxide,
which act by both absorbing and reflecting the UV rays.6 However, these require frequent
application, and if they are not micronized, they may cause a visible white residue on the
skin and occasionally lead to breakouts or acne. These factors may therefore restrict their
usage.7,8 Although they have been approved by the FDA, recent toxicity studies conducted
on zebrafish models showed that the mineral filters incur photooxidation and become
toxic after 2 hours of light exposure.1 Thus, there is a great need to formulate sunscreens
with naturally derived photoprotectants with broad spectrum anti-UV coverage and a low
concentration of chemical UV filters. Phytoconstituents—like polyphenols, flavonoids,
tannins, anthocyanins, and so forth—have been studied for their prospective use in the
field of radiation protection.9–11 However, much remains to be accomplished in terms of
their stability and efficacy.
Exposure to UV radiation triggers the accumulation of high levels of reactive oxygen
species (ROS), which causes excessive cell death resulting in wrinkling and skin dryness.12
Inflammation of the skin and melanomas are both associated with the accumulation of
ROS.13 Antioxidants that are normally present in skin are unable to defend excessive ROS
concentrations. Alternatively, natural pigments like carotenoids, which are recognized for
their antioxidant and anti-inflammatory properties, can be employed as therapeutic agents
for their dual role as an antioxidant and a photoprotectant. Some of the algal carotenoids—
like astaxanthin,14 fucoxanthin,15 β-carotene, and lutein16 — are used as cosmeceuticals
because of their antioxidant role and their anti-aging effects on skin. However, it is
important to emphasize that the cost of pigments derived from algae is nearly double that
of synthetic alternatives.17 The growing popularity of naturally derived cosmetic ingredients
among consumers has raised interest in microbial carotenoids. Due to simpler extraction
processes and cultivation techniques, microbial carotenoids have an advantage over algal
carotenoids.18 Moreover, microbe-derived carotenoids as active sunscreen ingredients
have not been explored as often. Therefore, the objective of the present work was to use
carotenoids from an indigenous isolate, Rhodococcus kroppenstedtii, as active components in
sunscreen formulation and to evaluate their stability and efficacy.
MATERIALS AND METHODS
CHEMICALS
All of the chemicals used in the study were of analytical grade and were purchased from
Sisco Research Laboratories (Hi-media Lab Pvt. Ltd.) and Research-Lab Fine Chem
Industries (Mumbai, India).
MICROORGANISM
An orange-red pigmented actinobacteria R kroppenstedtii (Accession No. MH715196) was
isolated from Rajapur Hot Water Spring of the Ratnagiri district in Maharashtra, India.
The culture was maintained on Tryptic Soy Agar at 4°C and subcultured regularly.