Lemon balm extract (Melissa officinalis, L.) promotes melanogenesis and prevents UVB-induced oxidative stress and DNA damage in a skin cell model
Introduction
The skin is the largest organ of the human body, participates in sensitivity and temperature maintenance and offers protection from chemicals, microorganisms and UV radiation [1]. An excessive UV exposition can lead to several skin pathological disorders, including erythema, immunosuppression, edema, sunburn, hyperplasia, hyperpigmentation, premature aging and skin cancer [2]. UV radiation is divided into long wave UVA (315–400 nm, 90% of UV radiation), medium wave UVB (280–315 nm, 5% of UV radiation), and short wave UVC (200–280 nm). UVB is one thousand times more capable of causing sunburn than UVA and is considered the most damaging and genotoxic [3].
Melanin is the main skin protective barrier that acts by absorbing and scattering UV radiation. Nevertheless, other intracellular molecules are targeted (DNA, RNA, lipids and proteins). The direct effect of UVB on DNA leads to the formation of cyclobutane pyrimidine dimers (CPDs) and to a lesser extent pyrimidine (6–4) pyrimidone (6-4PPs) photoproducts. When these alterations are not well repaired, the resulting substitution/transition mutations (cytosine-thymine) in the epidermal cells can lead to the development of skin cancer [4], [5].
UVB, together with UVA, generates superoxide (O2), either directly or through enzyme activation [6], [7]. This is the most promptly generated oxygen radical species (ROS) and is rapidly derived into H2O2, which forms OH upon the Fenton reaction [4]. UVB induced OH is postulated to be responsible for the formation of DNA single-strand breaks (SSBs) and also for lipid peroxidation through the generation of lipoperoxy radicals (ROO), malondialdehyde (MDA) and 4-hydroxy-2-nonenal (HNE). Additionally, UVB-induced ROS interact with numerous cellular targets and receptors that regulate crucial pathways related to inflammation, cell survival, cell growth and differentiation in human keratinocytes: the NF-κB, the AP-1 transcription factor, the mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK1/2) pathways [8], [9], [10]. Most of these effects lead to extracellular matrix degeneration by proteases activation and skin photoaging [1].
Plant polyphenols possess strong free radical scavenging properties and have exhibited the capacity to modulate multiple cellular pathways [11]. Recently, their potential skin photoprotective effects have gained considerable attention [12]. The UVB protective effects of botanical extracts, such as Punica granatum [13], citrus and rosemary [14], green tea polyphenols [15] and pure compounds, such as resveratrol [16], genistein [17], [18] and hydroxytyrosol [19] has been reported. Recently our group has demonstrated the synergistic protective effect of rosemary and citrus polyphenolic extracts both in vitro and in vivo [14].
Lemon balm (Melissa officinalis, L.) is a representative of the Lamiaceae family, native to Europe but with a worldwide distribution. This herb is used not only for ornamental purposes but also for medicine and cosmetics. It is commonly used for insomnia and anxiety [20], herpes [21], and indigestion [22], as an antioxidant [23] and as an antimicrobial agent [24]. Lemon balm extraction may lead to the essential oil and the lemon balm polyphenolic extract (LBE), which is enriched in phenylpropanoid derivatives and flavonoids. The major phenolic compound found in the polyphenolic extract is rosmarinic acid (RA), which is an ester of caffeic acid, and 3,4-dihydroxyphenyllactic acid [25] (Fig. 1, see insert). The antioxidant activity of LBE has been previously characterized in both in vitro and in vivo models [26], [27], [28], [29].
In the present study, the UVB protective effects of LBE and its major polyphenol RA were explored and compared in human keratinocytes. The potential of LBE to protect human keratinocytes from UVB-induced oxidative stress and to alleviate DNA damage was studied. The protective effect through melanogenesis activation was also studied in a cellular model.
Section snippets
Materials and LBE
Human keratinocytes (the spontaneously immortalized cell line HaCaT) were obtained from Cell lines Service GmbH, CLS (Eppelheim, Germany). Dulbeccós modified Eaglés medium (DMEM), fetal bovine serum (FBS), and penicillin-streptomycin were obtained from Gibco/Thermo Fisher Scientific (Waltham, MA, USA). RA (96%) and the rest of the reagents were purchased from Sigma-Aldrich (St. Louis, MO, USA). LBE standardized containing 18.0 ± 0.3% RA (w/w) was kindly provided by NUTRAFUR, SA – Frutarom Group
Characterization of LBE by HPLC–MS/MS
The major components of LBE were identified by HPLC-DAD-ESI-IT-MS/MS as described in the Methods section. The main polyphenolic compounds were identified using a library of phenolic compounds by comparing their retention times, UV spectra and MS/MS data with those of commercial standards or reports in the literature. Fig. 1 shows the chromatogram obtained at 280 nm for LBE. Thirteen major phenolic compounds were identified in LBE as detailed in Table 1 and were assigned numbers 1–13 according to
Discussion
In this study, the capacity of a lemon balm extract to prevent signs of cellular damage induced by UVB was explored. The major compound in LBE was RA (18% w/w), but other phenylpropanoid derivatives were also present (caffeic acid, salvianolic acid, yunnaneic acid, sagerinic acid and lithospermic acid; Supplementary Fig. S3). Additionally, small amounts of the flavone luteolin-3′-O-glucuronide were found. Hence, most of the effects observed must be due to RA and related polyphenols. Our results
Conflict of interest
The authors declare no conflicts of interest.
Acknowledgements
This investigation was supported by project AGL2015-67995-C3-1-R and the Torres-Quevedo (PTQ-14-07243) fellowship to E. Barrajón-Catalán from the Spanish Ministry of Science and Innovation, grants PROMETEO/2012/007 and 2016/006 and VALi+D fellowships (ACIF/2010/162 and ACIF/2013/064) from Generalitat Valenciana (GV) and CIBER (CB12/03/30038, Fisiopatología de la Obesidad y la Nutrición, CIBERobn, Instituto de Salud Carlos III). We thank NUTRAFUR, SL for providing us with the raw materials. We
References (51)
- et al.
UVB light stimulates production of reactive oxygen species: unexpected role for catalase
J. Biol. Chem.
(2003) - et al.
NADPH oxidase and cyclooxygenase mediate the ultraviolet B-induced generation of reactive oxygen species and activation of nuclear factor-kappaB in HaCaT human keratinocytes
Biochimie
(2004) - et al.
The flavonoids apigenin and luteolin suppress ultraviolet A-induced matrix metalloproteinase-1 expression via MAPKs and AP-1-dependent signaling in HaCaT cells
J. Dermatol. Sci.
(2011) - et al.
Protective effects of citrus and rosemary extracts on UV-induced damage in skin cell model and human volunteers
J. Photochem. Photobiol. B
(2014) - et al.
Inhibition of ultraviolet light-induced oxidative events in the skin and internal organs of hairless mice by isoflavone genistein
Cancer Lett.
(2002) - et al.
Melissa officinalis oil affects infectivity of enveloped herpesviruses
Phytomedicine
(2008) - et al.
The natural antioxidant rosmarinic acid spontaneously penetrates membranes to inhibit lipid peroxidation in situ
BBA Biomembr.
(2011) - et al.
Antioxidant activity, genotoxicity and cytotoxicity evaluation of lemon balm (Melissa officinalis L.) ethanolic extract: its potential role in neuroprotection
Ind. Crop Prod.
(2013) - et al.
Total phenolic content: antioxidant activity and toxicity of aqueous extracts from selected Greek medicinal and aromatic plants
Ind. Crop Prod.
(2014) - et al.
Isolation, characterization and antioxidant capacity assessment of the bioactive compounds derived from Hypoxis rooperi corm extract (African potato)
Food Chem.
(2007)
Cistaceae aqueous extracts containing ellagitannins show antioxidant and antimicrobial capacity, and cytotoxic activity against human cancer cells
Food Chem. Toxicol.
Luteolin 3′-glucuronide, the major flavonoid from Melissa officinalis subsp. officinalis
Fitoterapia
Rosmarinic acid induces melanogenesis through protein kinase A activation signaling
Biochem. Pharmacol.
UVB activates ERK1/2 and p38 signaling pathways via reactive oxygen species in cultured keratinocytes
J. Invest. Dermatol.
Lipid peroxidation product 4-hydroxy-2-nonenal modulates base excision repair in human cells
DNA Repair (Amst.)
Correlation between plasma antioxidant capacity and verbascoside levels in rats after oral administration of lemon verbena extract
Food Chem.
UV-induced histone H2AX phosphorylation and DNA damage related proteins accumulate and persist in nucleotide excision repair-deficient XP-B cells
DNA Repair (Amst.)
H2AX: the histone guardian of the genome
DNA Repair
Enrichment of antioxidant compounds from lemon balm (Melissa officinalis) by pressurized liquid extraction and enzyme-assisted extraction
J. Chromatogr. A
Chemical composition: antioxidant and anticholinesterase activity of Melissa officinalis
Ind. Crop Prod.
Rosmarinic acid: a photo-protective agent against UV and other ionizing radiations
Food Chem. Toxicol.
Orally administered rosmarinic acid is present as the conjugated and/or methylated forms in plasma, and is degraded and metabolized to conjugated forms of caffeic acid, ferulic acid and m-coumaric acid
Life Sci.
Skin aging
Botanical antioxidants in the prevention of photocarcinogenesis and photoaging
Exp. Dermatol.
Natural phenolics in the prevention of UV-induced skin damage. A review
Biomed. Pap. Med. Fac. Univ. Palacky Olomouc Czech. Repub.
Cited by (0)
- 1
These authors have equally contributed to this research and are listed in random order.
- 2
Frutarom Group.