Germinated Riceberry Rice Enhanced Protocatechuic Acid and Vanillic Acid to Suppress Melanogenesis through Cellular Oxidant-Related Tyrosinase Activity in B16 Cells

Resveratrol-Enriched Rice Callus Extract Inhibits Oxidative and Cellular Melanogenic Activities in Melan-A Cells

The excessive production of melanin can cause skin diseases and hyperpigmentation. In this study, resveratrol contained in Dongjin rice seed (DJ526) was increased through callus induction. The antioxidant capacity of resveratrol-enriched rice callus was evaluated using the ABTS radical scavenging method and was equivalent to that of vitamin C. DJ526 rice callus extract significantly increased antioxidant activities in a concentration-dependent manner. The anti-melanogenesis effects of DJ526 rice callus extract were also evaluated in melan-a cells. Resveratrol-enriched rice callus extract significantly (i) decreased the size and number of melanin-containing cells, (ii) suppressed the activity of cellular tyrosinase and melanin content, (iii) downregulated the expression of microphthalmia-associated transcription factor, tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2, (iv) increased the expression of phosphorylated extracellular signal-regulated kinase 1/2 and protein kinase B, and (v) inhibited the activation of phosphorylated p38 in melan-a cells. From the above observations, DJ526 rice callus extract showed strong antioxidant and anti-melanogenesis activity at the concentration test. These findings indicate the potential of resveratrol-enriched rice callus as a novel agent for controlling hyperpigmentation.

Metabolomics Reveals Antioxidant Metabolites in Colored Rice Grains

Colored rice is richer in nutrients and contains more nutrients and bioactive substances than ordinary white rice. Moderate consumption of black (purple) rice has a variety of physiological effects, such as antioxidant effects, blood lipid regulation, and blood sugar control. Therefore, we utilized nontargeted metabolomics, quantitative assays for flavonoid and phenolic compounds, and physiological and biochemical data to explore the correlations between metabolites and the development of antioxidant characteristics in pigmented rice seeds. The findings indicated that, among Yangjinnuo 818 (YJN818), Hongnuo (HN), Yangchannuo 1 hao (YCN1H), and Yangzi 6 hao (YZ6H), YZ6H exhibited the highest PAL activity, which was 2.13, 3.08, and 3.25 times greater than those of YJN818, HN, and YCN1H, respectively. YZ6H likewise exhibited the highest flavonoid content, which was 3.8, 7.06, and 35.54 times greater than those of YJN818, HN, and YCN1H, respectively. YZ6H also had the highest total antioxidant capacity, which was 2.42, 3.76, and 3.77 times greater than those of YJN818, HN, and YCN1H, respectively. Thus, purple rice grains have stronger antioxidant properties than other colored rice grains. Receiver operating characteristic (ROC) curve analysis revealed that trans-3,3',4',5,5',7-hexahydroxyflavanone, phorizin, and trilobatin in the YZ6H, HN, and YCN1H comparison groups all had area under the curve (AUC) values of 1. Phlorizin, trans-3,3',4',5,5',7-hexahydroxyflavanone, and trilobatin were recognized as indices of antioxidant capability in colored rice in this research. This research adds to the understanding of antioxidant compounds in pigmented rice, which can increase the nutritional value of rice and promote the overall well-being of individuals. This type of information is of immense importance in maintaining a balanced and healthy diet.

Inhibitory Effects of Polyphenol- and Flavonoid-Enriched Rice Seed Extract on Melanogenesis in Melan-a Cells via MAPK Signaling-Mediated MITF Downregulation

Melanin production is an important process that prevents the host skin from harmful ultraviolet radiation; however, an overproduction of melanin results in skin diseases. In the present study, we determined the antioxidative and anti-melanogenic activities of polyphenol- and flavonoid-enriched rice seed extracts in melan-a cells. The polyphenol and flavonoid content of Hopum (HP) and Sebok (SB) rice seed extracts was measured. The antioxidant capacity was determined using the ABTS radical scavenging method. SB contained high amounts of polyphenols and flavonoids, which significantly increased antioxidative activity compared with HP. Various concentrations of these extracts were evaluated in a cytotoxicity using melan-a cells. At 100 µg/mL, there was no significant difference for all treatments compared with untreated cells. Therefore, 100 µg/mL was selected as a concentration for the further experiments. SB significantly suppressed the phosphorylation/activation of p-38 MAPK, increased the expression of phosphorylated ERK 1/2 and Akt, and downregulated the microphthalmia-associated transcription factor (MITF). This resulted in decreased levels of tyrosinase and tyrosinase-related protein-1 and -2. These results indicate the potential of polyphenol- and flavonoid-enriched rice seed as a treatment for hyperpigmentation.

Use of Germination to Enhance Resveratrol Content and Its Anti-Inflammatory Activity in Lipopolysaccharide-Stimulated RAW264.7 Cells

Inflammation is triggered by a variety of danger signals and is now a worldwide concern. Resveratrol, a natural nonflavonoid polyphenol found in naturally consumed plants and foods, has a wide spectrum of bioactive potency. We successfully generated resveratrol-enriched rice by introducing the resveratrol biosynthesis gene into Dongjin rice. In this study, resveratrol- and piceid-enriched rice (DJ526) was investigated for its anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW264.7 cells compared to normal rice (DJ). In addition, the 5-day-old germinated DJ526 (DJ526_5) was tested for its anti-inflammatory effects. The piceid and resveratrol amounts increased in DJ526_5 by germination. Treatment of LPS-stimulated RAW264.7 cells with resveratrol-enriched rice seed extracts (DJ526_0 and DJ526_5) significantly decreased the production of nitric oxide (NO) and the inflammatory mediator prostaglandin E2 (PGE₂), downregulated proinflammatory gene expression, and inhibited nuclear factor kappa B (NF-κB) p65, p38 mitogen-activated protein kinase, and extracellular signal-regulated kinase 1/2 (ERK 1/2) phosphorylation. These findings demonstrated the anti-inflammatory mechanisms of resveratrol-enriched rice in LPS-stimulated RAW264.7 cells. Furthermore, resveratrol-enriched rice could be a potential source of anti-inflammatory agents.

Phytochemical compositions and biological activities of the branches and leaves of Ormosia hosiei Hemsl. et Wils

Ormosia hosiei Hemsl. et Wils. is an economical and medicinal plant, increasingly cultivated in China; however, its branches and leaves are often pruned as waste. This is the first study focused on the phytochemical profiles and antioxidant, anti-α-glucosidase, anti-tyrosinase, and anti-neuroinflammatory activities of the branches and leaves of O. hosiei. Herein, thirty-seven characteristic compounds were identified by UPLC-MS/MS and twelve were detected for the first time in O. hosiei. Twenty-seven phenolics were further quantified and significant differences in phenolic compositions between the branches and leaves of O. hosiei were observed. The ethanol extracts exhibited promising antioxidant, anti-α-glucosidase, anti-tyrosinase, and anti-neuroinflammatory effects, and the bioactivities significantly correlated with total phenolic content and twelve individual phenolics. Naringin, genistein, vitexin, vitexin-2-O-rhamnoside, syringaresinol and syringaresinol-4-O-β-D-glucopyranoside can be considered potential quality markers of O. hosiei. Our results provided solid evidence that the branches and leaves of O. hosiei deserve more attention and exploitation, considering the potential to be developed as functional foods or herbal medicines.

Phytochemicals as Immunomodulatory Agents in Melanoma

Cutaneous melanoma is an immunogenic highly heterogenic tumor characterized by poor outcomes when it is diagnosed late. Therefore, immunotherapy in combination with other anti-proliferative approaches is among the most effective weapons to control its growth and metastatic dissemination. Recently, a large amount of published reports indicate the interest of researchers and clinicians about plant secondary metabolites as potentially useful therapeutic tools due to their lower presence of side effects coupled with their high potency and efficacy. Published evidence was reported in most cases through in vitro studies but also, with a growing body of evidence, through in vivo investigations. Our aim was, therefore, to review the published studies focused on the most interesting phytochemicals whose immunomodulatory activities and/or mechanisms of actions were demonstrated and applied to melanoma models.

Riceberry Rice Germination and UVB Radiation Enhance Protocatechuic Acid and Vanillic Acid to Reduce Cellular Oxidative Stress and Suppress B16F10 Melanogenesis Relating to F-Actin Rearrangement

Ultraviolet type B (UVB) radiation plays an important role in hyperpigmentation disorder, which induces cellular oxidative stress and causes abnormal melanin production and secretion. The stress condition plays an essential role in actin polymerization relating to F-actin rearrangement and forms dendrite to send melanin pigment to the uppermost layer of the skin. Phenolic compounds are secondary metabolites that mainly synthesize under stress conditions to protect plants from harmful environments and have been reported as effective agents in anti-oxidant and anti-melanogenesis. However, the influence of phenolic compounds on F-actin rearrangement-associated dendrite formation has not been studied so far. Hence, this study aimed to investigate the enhancing phytophenolic targets in riceberry rice (Oryza sativa L.) germination and UVB radiation (RR-GR) to suppress melanogenesis relating to F-rearrangement. As a result, the RR-GR had the potential to enhance phenolic acids such as protocatechuic and vanillic acid, which have been proven to possess anti-oxidant activity and anti-tyrosinase properties. Riceberry rice's modification showed the potential to reduce cellular oxidative stress and suppress B16F10 melanogenesis relating to F-actin rearrangement that is associated with dendrite formation.

Protopanaxadiol-Enriched Rice Extracts Suppressed Oxidative and Melanogenic Activities in Melan-a Cells

Concerns about hyperpigmentation and skin appearance have led to increasing research into the prevention and altering of skin pigmentation. Natural compounds may be of interest in the search for skin-lightening actives. Protopanaxadiol (PPD), a gut microbiome-induced ginseng metabolite, has been reported to have anti-melanogenic effects. This study aimed to evaluate the antioxidative and anti-melanogenic effects of PPD-enriched rice seed extracts on melan-a cells. The antioxidant and cytotoxicity activities of the extracts were investigated in melan-a cells before measuring their responses to melanogenic activities. The extracts significantly enhanced the antioxidant potency compared with normal rice seed extract. PPD-enriched rice seed extracts (i) significantly downregulated microphthalmia-associated transcription factor, which led to a reduction in tyrosinase and tyrosinase-related protein-1 and -2, (ii) decrease in the cellular tyrosinase activity and melanin content, (iii) reduction in the number of melanin-containing cells, (iv) promotion of melanogenesis downregulators, phosphorylation of extracellular signal-regulated kinase 1/2 and protein kinase B, and (v) downregulation of the phosphorylated p38 mitogen-activated protein kinase and melanin synthesis. These results indicate the feasibility of PPD-enriched rice seed extracts as a novel agent for suppressing melanogenesis and controlling hyperpigmentation.

Nypa fruticans Wurmb inhibits melanogenesis in isobutylmethylxanthine‑treated melanoma via the PI3K/AKT/mTOR/CREB and MAPK signaling pathways

Malignant melanoma is responsible for 3.0 and 1.7% of cases of tumor incidence and tumor-associated mortality, respectively, in the Caucasian population. Melanoma is a type of skin cancer that occurs when melanocytes mutate and divide uncontrollably. Nypa fruticans Wurmb (NF) is abundant in phytochemicals (polyphenols and flavonoids) and is traditionally used to treat diseases of the respiratory tract. The present study investigated the inhibitory effect of the ethyl acetate fraction of NF (ENF) on melanogenesis-related factors in isobutylmethylxanthine-treated B16F10 melanoma cells. Phenolics and flavonoids (caffeic acid, catechin, epicatechin and hirsutine) in ENF were analyzed via liquid chromatography-mass spectrometry. In addition, the main factors involved in melanogenesis were identified using immunoblotting, reverse transcription-polymerase chain reaction (RT-PCR), RT-quantitative PCR and immunofluorescence. ENF significantly suppressed the expression of tyrosinase (TYR) and TYR-related proteins 1 and 2 (TYRP-1/2), which are the main factors involved in melanogenesis. ENF also inhibited the expression of microphthalmia-associated transcription factor (MITF) by phosphorylating the related cell signaling proteins (protein kinase B, mammalian target of rapamycin, phosphoinositide 3-kinase and cAMP response element-binding protein). Furthermore, ENF inhibited the phosphorylation of extracellular signal-regulated kinase and thereby downregulated melanogenesis. In conclusion, ENF inhibited melanogenesis by suppressing MITF, which controls TYRP-1/2 and TYR. These results suggested that ENF may be a natural resource that can inhibit excessive melanin expression by regulating various melanogenesis pathways.

Biosynthesis of vanillic acid by Ochrobactrum anthropi and its applications

Vanillic acid has always been in high-demand in pharmaceutical, cosmetic, food, flavor, alcohol and polymer industries. Present study achieved highly pure synthesis of vanillic acid from vanillin using whole cells of Ochrobactrum anthropi strain T5_1. The complete biotransformation of vanillin (2 g/L) in to vanillic acid (2.2 g/L) with 95 % yield was achieved in single step in 7 h, whereas 5 g/L vanillin was converted to vanillic acid in 31 h. The vanillic acid thus produced was validated using LC-MS, GC-MS, FTIR and NMR. Further, vanillic acid was evaluated for in vitro anti-tyrosinase and cytotoxic properties on B16F1 skin cell line in dose dependent manner with IC₅₀ values of 15.84 mM and 9.24 mM respectively. The in silico Swiss target study predicted carbonic acid anhydrase IX and XII as key targets of vanillic acid inside the B16F1 skin cell line and revealed the possible mechanism underlying cell toxicity. Molecular docking indicated a strong linkage between vanillic acid and tyrosinase through four hydrogen and several hydrophobic bonds, with ΔG of -3.36 kJ/mol and Ki of 3.46 mM. The bioavailability of vanillic acid was confirmed by the Swiss ADME study with no violation of Lipinski's five rules.

Chemical composition and biological activities of essential oils from six lamiaceae folk medicinal plants

Essential oils have attracted wide attention in recent years due to their extensive applications in natural functional ingredients, pharmaceutical preparations, biomedical products, and the cosmetics industry. In this study, the chemical compositions and biological activities of essential oils extracted from six Lamiaceae herbs, including Pogostemon cablin (Blanco) Benth. (PCEO), Perilla frutescens (L.) Britton (PFEO), Salvia japonica Thunb. (SJEO), Rosmarinus officinalis L. (ROEO), Lavandula angustifolia Mill. (LAEO), and Agastache rugosa (Fisch. & C. A. Mey.) Kuntze (AREO), were determined and analyzed. A total of 167 components were identified from the six essential oils by GC-MS analysis, with 35, 24, 47, 46, 54, and 37 components in PCEO, PFEO, SJEO, ROEO, LAEO, and AREO, respectively. Hierarchical cluster analysis of chemical compositions showed that the composition of the six essential oils was significantly different in content, and they were clearly divided into six classes. However, all of these six essential oils exhibited promising anti-inflammatory activity by inhibiting the expression of interleukin-1, interleukin-6, tumor necrosis factor-α, and cyclooxygenase-2 in rats with adjuvant arthritis, among which PFEO had the best performance. In addition, the six essential oils displayed significant cytotoxicity on B16 (IC₅₀ = 86.91-228.91 μg/mL) and LNCaP cell lines (IC₅₀ = 116.4-189.63 μg/mL). Meanwhile, all of them presented satisfactory antioxidant activity (IC₅₀ = 4.88-13.89 μg/mL) compared with Trolox C (IC₅₀ = 13.83 μg/mL), and SJEO (IC₅₀ = 7.93 μg/mL) served as an optimal candidate natural antioxidant by DPPH assay. Taken together, these results indicate that the six Lamiaceae essential oils manifest excellent and diverse biological activities, enabling them to be used as perfect natural functional ingredients in antioxidant, antitumor, or anti-arthritic drugs. This study provides more references for pharmaphylogeny research and drug discovery from folk medicinal plants.

Camellia japonica Essential Oil Inhibits α-MSH-Induced Melanin Production and Tyrosinase Activity in B16F10 Melanoma Cells

Essential oils are aromatic oils extracted from the leaves, stems, peels, petals, and roots of aromatic plants grown in nature or grown in organic methods and have various medical effects as natural substances. The essential oil extracted from Camellia japonica seeds exhibits various functional properties; however, its tyrosinase inhibitory activity has not been investigated extensively. This study is performed to investigate the chemical composition and tyrosinase inhibitory activity of Camellia japonica seed essential oil (CJS-EO). Hexamethylcyclotrisiloxane (42.36%) and octamethylcyclotetrasiloxane (23.28%) are the two primary components of CJS-EO, as identified via gas chromatography-mass spectrometry. The inhibitory activities of CJS-EO and positive control arbutin are further evaluated against mushroom tyrosinase. The results show that CJS-EO and arbutin inhibit tyrosinase activity. Moreover, CJS-EO significantly inhibits melanogenesis in the α-melanocyte-stimulating hormone-treated group, and a significant amount of melanin is suppressed. To ascertain the cause of the CJS-EO tyrosinase inhibitory effect and melanin reduction effect, genetic and protein analyses are performed. Based on our results, we tentatively conclude that CJS-EO can inhibit melanocytes from harmful factors such as tyrosinase-related protein. These results demonstrate that CJS-EO possesses potent antityrosinase activity and may be a good skin-whitening agent.

Antioxidant Effects of Anthocyanin-Rich Riceberry™ Rice Flour Prepared Using Dielectric Barrier Discharge Plasma Technology on Iron-Induced Oxidative Stress in Mice

Redox-active iron generates reactive oxygen species that can cause oxidative organ dysfunction. Thus, the anti-oxidative systems in the body and certain dietary antioxidants, such as anthocyanins, are needed to control oxidative stress. We aimed to investigate the effects of dielectric barrier discharge (DBD) plasma technology in the preparation of Riceberry™ rice flour (PRBF) on iron-induced oxidative stress in mice. PRBF using plasma technology was rich in anthocyanins, mainly cyanidine-3-glucoside and peonidine-3-glucoside. PRBF (5 mg AE/mg) lowered WBC numbers in iron dextran (FeDex)-loaded mice and served as evidence of the reversal of erythrocyte superoxide dismutase activity, plasma total antioxidant capacity, and plasma and liver thiobarbituric acid-reactive substances in the loading mice. Consequently, the PRBF treatment was observed to be more effective than NAC treatment. PRBF would be a powerful supplementary and therapeutic antioxidant product that is understood to be more potent than NAC in ameliorating the effects of iron-induced oxidative stress.

Determination of the Chemical Composition, Antioxidant, and Enzyme Inhibitory Activity of Onosma mollis DC

Onosma species have long been used traditionally for respiratory tract infections, abdominal pain, wound treatment, burns, and constipation. This study aims to investigate the chemical composition and in vitro antioxidant and enzyme inhibitory activities of ethyl acetate (EtOAc), methanol (MeOH), and water extracts of Onosma mollis DC. MeOH extract was richer in both phenolics and flavonoids than other extracts (44.06 mg GAEs/g and 41.57 mg QEs/g, respectively). The findings obtained from the results of the chromatographic analysis also supported the results of the spectrophotometric analysis. The MeOH extract was the richest in terms of most of the phytochemicals screened. Apigenin 7-glucoside, luteolin 7-glucoside, rosmarinic acid, vanillic acid, and pinoresinol were over 1000.0 μg/g in MeOH extract. The extract in question showed the highest activity in phosphomolybdenum, DPPH, and ABTS radical scavenging and CUPRAC and FRAP reducing power activity assays (2.01, 3.33, 2.30, 1.48, and 0.79 mg/ml, respectively). The water extract presented the highest activity in the ferrous ion chelating assay (1.01 mg/ml). While EtOAc extract showed high activity in acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α-glucosidase inhibitory activity tests (1.11, 1.49, and 1.07 mg/ml, respectively), MeOH extract showed significant efficacy in tyrosinase and α-amylase inhibitory activity assays (2.94 and 2.08 mg/ml, respectively). There was a high correlation between the total phenolics/flavonoids of the extracts and their antioxidant activities (correlation coefficients were over 0.9). In addition, the phytochemicals mentioned above were found to contribute significantly to the antioxidant activity. It was concluded that a more detailed analysis should be done to determine the compounds responsible for the enzyme inhibitory activities of the extracts.

Skin Pigmentation Abnormalities and Their Possible Relationship with Skin Aging

Skin disorders showing abnormal pigmentation are often difficult to manage because of their uncertain etiology or pathogenesis. Abnormal pigmentation is a common symptom accompanying aging skin. The association between skin aging and skin pigmentation abnormalities can be attributed to certain inherited disorders characterized by premature aging and abnormal pigmentation in the skin and some therapeutic modalities effective for both. Several molecular mechanisms, including oxidative stress, mitochondrial DNA mutations, DNA damage, telomere shortening, hormonal changes, and autophagy impairment, have been identified as involved in skin aging. Although each of these skin aging-related mechanisms are interconnected, this review examined the role of each mechanism in skin hyperpigmentation or hypopigmentation to propose the possible association between skin aging and pigmentation abnormalities.

Modified Riceberry rice extract suppresses melanogenesis-associated cell differentiation through tyrosinase-mediated MITF downregulation on B16 cells and in vivo zebrafish embryos

Background and purpose:

Excessive melanin production caused by overactive tyrosinase (TYR) enzyme results in several dermatological problems. The TYR inhibitor, derived from metabolite changes during fermentation, has been well recognized for pigmentation control.

Experimental approach:

This study is interested in alternative anti-melanogenic agents from bio-modified Riceberry rice through fermentation. Modified Riceberry rice extract (MRB) was evaluated for its cytotoxicity, melanin content, melanin excretion, and TYR activity in B16 cells. TYR and their melanogenesis-related molecules such as TYR-related proteins-1 and -2, and microphthalmia-associated transcription factor (MITF) were determined. The anti-melanogenic activity and toxicity were also tested using the embryonic zebrafish model. Furthermore, comprehensive genotoxicity testing was verified by cytokinesis-block micronucleus cytome assay.

Findings/Results:

The study found that non-cytotoxic concentrations of MRB at 20 and 40 mg/mL inhibited melanogenesis and melanin excretion by interfering B16 cell morphology. Cellular TYR enzymatic activity was also suppressed in the treated cells. The mRNA transcription and protein expression levels of TYR and MITF decreased by dose-dependent and time-dependent manners with MRB treatment. In the animal model, MRB was found to be safe and potent for melanogenesis-related TYR inhibition in embryonic zebrafish at 20 and 30 mg/mL. The toxicity of effective doses of MRB showed no genotoxicity and mutagenicity.

Conclusion and implications:

This study suggests that MRB has anti-melanogenesis potential through TYR and its-related protein inhibitions. MRB is also safe for applications and maybe a promising anti-melanogenic agent for hyperpigmentation control.