Oenothera laciniata Hill Extracts Exhibits Antioxidant Effects and Attenuates Melanogenesis in B16-F10 Cells via Downregulating CREB/MITF/Tyrosinase and Upregulating p-ERK and p-JNK

Abstract

Oenothera laciniata Hill is a perennial herb traditionally used to alleviate inflammatory complications. This study investigated the antioxidant and anti-melanogenic activities of O. laciniata. The methanolic extract (OLM) of O. laciniata and its different fractions, including ethyl acetate (OLEF), n-butanol (OLBF), and water (OLWF) fractions, were prepared. Antioxidant activities were evaluated by total phenolic content, the radical-scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH•), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+•), and superoxide anion (O2−•), reducing capacity, and metal chelating ability. OLM and its fractions exhibited potent antioxidant activity in these in vitro assays, with a correlation between radical-scavenging activity and total phenolic content. OLM and its fractions inhibited the mushroom tyrosinase activity superior to the reference control, ascorbic acid. In B16-F10 melanoma cells, OLM and its fractions significantly decreased melanin production and tyrosinase activity. Mechanistic investigations revealed that OLM and its fractions inhibited tyrosinase and TRP-2 expressions via downregulating MITF and phosphorylated CREB and differentially inducing ERK or JNK phosphorylation. Additionally, OLM and its fractions caused no significant cytotoxicity towards B16-F10 or skin fibroblast cells at concentrations used in these cellular assays. These findings demonstrated the potential of O. laciniata extracts as the ideal skin protective agent with dual antioxidant and anti-melanogenic activities.

The Modulation of Melanogenesis in B16 Cells Upon Treatment with Plant Extracts and Isolated Plant Compounds

“…The opposite effect on phosphorylation of PKA and CREB are interfered with by Nelumbo nucifera leaf extract [ 104 ]. Rhodiola rosea root extract [ 105 ], Elaeagnus umbellate branches and leaves [ 106 ], Oenothera laciniata extracts [ 107 ] and Kadsura coccinea roots, stems, leaves, fruits [ 108 ] extracts inhibited the phosphorylation of CREB followed by downregulation of MITF and TYR expression. Similar inhibitory effects on CREB exerts isoorientin, a flavone glycoside, derived from Gentiana veitchiorum flowers [ 109 ], polysaccharide from Morchella esculenta fruits [ 110 ], loganin, an iridoid monoterpenoid, from Cornus officinalis [ 111 ], kaempferol-7-O-β-D-glucuronide, flavonol glucoside, and tilianin, a flavonoid glycoside, isolated from aerial parts Cryptotaenia japonica [ 112 ], moracin J, a 2-arylbenzofuran flavonoid, from leaves of Morus alba [ 113 ], and 6-O-isobutyrylbritannilactone from the flowers of Inula britannica [ 114 ].…”

“…Many studies have examined the influence of plant extracts and isolated compounds on various MAPKs in B16 melanoma cells. Extracts derived from Artocarpus communis heartwood [ 145 ], Phyla nodiflora aerial part [ 146 ] and Oenothera laciniata [ 107 ] were found to modulate ERK and JNK phosphorylation, resulting in anti-melanogenic effects. Similar results were obtained for kaempferol-7-O-β-D-glucuronide and tilianin, a flavonoid glycoside isolated from the aerial parts of Cryptotaenia japonica [ 126 ].…”

Investigations into Chemical Components from Monascus purpureus with Photoprotective and Anti-Melanogenic Activities

“…Alpha-MSH-stimulated tyrosinase activities in B16-F10 cells were used as an in vitro model for evaluating the anti-melanogenic potentials of bioactive products [57,60,65]. Briefly, B16-F10 cells were treated with 50 nM α-MSH for 24 h and then treated with vehicle or testing compounds for 48 h. The cells were collected with trypsinization and centrifuged at 12,000 rpm and 4 • C for 10 min.…”

“…Briefly, B16-F10 cells were treated with 50 nM α-MSH for 24 h and then treated with vehicle or testing compounds for 48 h. The cells were collected with trypsinization and centrifuged at 12,000 rpm and 4 • C for 10 min. The cellular melanin content and tyrosinase activity were determined as described previously [65,66].…”

Licorice zinc suppresses melanogenesis via inhibiting the activation of P38MAPK and JNK signaling pathway in Balb/c mice skin

“…Melanin formation is a complex process involving tyrosinase, tyrosinase-related protein-1 (TRP-1), and microphthalmia-associated transcription factor (MITF) [3][4][5] . MITF is active by cAMP response element-binding protein (CREB), which is regulated by cAMP 3,6 . Moreover, it was recently reported that UV radiation and α-melanocyte-stimulating hormone (α-MSH) activate adenyl cyclase to increase cAMP [7][8][9] .…”