Anti-melanoma potential of two benzoquinone homologues embelin and rapanone - a comparative in vitro study

Ethyl Acetate Fraction from Eleutherococcus divaricatus Root Extract as a Promising Source of Compounds with Anti-Hyaluronidase, Anti-Tyrosinase, and Antioxidant Activity but Not Anti-Melanoma Activity

Eleutherococcus divaricatus (Siebold and Zucc.) S. Y. Hu. has been used in Traditional Chinese Medicine (TCM) due to its anticancer, immunostimulant, and anti-inflammatory activities. However, its mechanism of action and chemical composition are still insufficiently understood and require more advanced research, especially for cases in which anti-inflammatory properties are beneficial. The aim of this study was to evaluate the impact of E. divaricatus root extracts and fractions on proinflammatory serum hyaluronidase and tyrosinase in children diagnosed with acute lymphoblastic leukemia. Antioxidant and anti-melanoma activities were also examined and correlated with metabolomic data. For the first time, we discovered that the ethyl acetate fraction significantly inhibits hyaluronidase activity, with mean group values of 55.82% and 63.8% for aescin used as a control. However, interestingly, the fraction showed no activity against human tyrosinase, and in A375 melanoma cells treated with a doxorubicin fraction, doxorubicin activity decreased. This fraction exhibited the most potent antioxidant activity, which can be attributed to high contents of polyphenols, especially caffeic acid (24 mg/g). The findings suggest an important role of the ethyl acetate fraction in hyaluronidase inhibition, which may additionally indicate its anti-inflammatory property. The results suggest that this fraction can be used in inflammatory-related diseases, although with precautions in cases of patients undergoing chemotherapy.

Pseudocereal Oils, Authenticated by Fourier Transform Infrared Spectroscopy, and their Chemopreventive Properties

Amaranth, quinoa, and buckwheat are the representatives of pseudocereals, different parts and by-products of which are used in daily nutrition and food processing industry. However, only scarce information exists on the bioactivity of their oils. Thus, oils obtained from amaranth, buckwheat, and red, yellow, and white quinoa seeds were evaluated in terms of their nutritional (fatty acid profile, squalene), cytotoxic (against normal and neoplastic gastrointestinal, prostate, and skin cells), anti-inflammatory and antiradical (interleukin 6, TNF-alpha, nitric oxide, DPPH, Total phenolics, and superoxide dismutase) potential in the in vitro model. Linoleic (42.9-52.5%) and oleic (22.5-31.1%) acids were the two main unsaturated, while palmitic acid (4.9-18.6%) was the major saturated fatty acid in all evaluated oils. Squalene was identified in all evaluated oils with the highest content in amaranth oil (7.6 g/100 g), and the lowest in buckwheat oil (2.1 g/100 g). The evaluated oils exerted a high direct cytotoxic impact on cancer cells of different origins, but also revealed anti-inflammatory and antiradical potentials. Yellow quinoa oil was the most active, especially toward skin (A375; IC50 6.3 µg/mL), gastrointestinal (HT29 IC50 4.9 µg/mL), and prostate cancer cells (LNCaP IC50 7.6 µg/mL). The observed differences in the activity between the oils from the tested quinoa varieties deserve further studies. High selectivity of the oils was noted, which indicates their safety to normal cells. The obtained results indicate that the oils are good candidates for functional foods with perspective chemopreventive potential.

Effect of Methyl Jasmonate Elicitation on Triterpene Production and Evaluation of Cytotoxic Activity of Mycelial Culture Extracts of Ganoderma applanatum (Pers.) Pat

Abiotic elicitation, a well-known strategy in mushroom biotechnology, promotes increased accumulation of secondary metabolites in mycelial cultures. The study aimed the effects of methyl jasmonate (MeJA) on the production of triterpenes in submerged cultures of Ganoderma applanatum. Further, the study evaluated the cytotoxic activity of the extract corresponding to the optimal elicitation variant in selected human cancer cell lines as well as the selectivity against normal cells. MeJA was added on days 1, 4, 6, and 8 in the 10-day growth cycle at concentrations of 10, 50, 100, 150, and 200 µM MeJA. The HPLC-DAD was used to analyze the triterpenes. The cytotoxic activity was tested using the MTTFc assay in grouped panels of skin, prostate, and gastrointestinal cancer cells. The results of the quantitative analyses confirmed the stimulating effect of MeJA on the production of ganoderic acid A and ganoderic acid C. The greatest increase in total triterpenes was found on day 6 of the culture cycle compared to the control group-with the concentration of MeJA-150 µM. Compared to the control samples, mycelial culture extract after the most productive elicitation variant showed significant cytotoxic activity against prostate cancer cells and moderate effects on melanoma cells. Ganoderma applanatum mycelial cultures can be proposed as a model to study the dynamics of the accumulation of compounds with therapeutic values through abiotic elicitation.

Optimization of Extraction Conditions and Cytotoxic Activity of Rapanone in Comparison to Its Homologue, Embelin

Rapanone is a plant-derived simple alkyl-dihydroxybenzoquinone structurally close to embelin, a well-known cytotoxic agent. The pharmacological characterization of rapanone is still incomplete, and to fill the data gap, a good source for its acquisition is required to conduct further research. This study aimed to optimize the conditions for the extraction of rapanone from the leaves of white-berried Ardisia crenata Sims. For this purpose, three methods were employed: heat reflux (HRE), shaking (SE), and ultrasound-assisted extraction (UAE), and such parameters as the extraction time, solvent, and the number of extractions from the same sample were set as experimental variables. Furthermore, cytotoxic activity toward prostate cancer, thyroid cancer, and colorectal carcinoma cell lines was investigated and compared with doxorubicin and embelin. The most effective and economical method for the extraction of rapanone was shown to be 20 min UAE with ethyl acetate or chloroform. Rapanone exhibited high cytotoxic activity against PC3 (IC₅₀ = 6.50 μg/mL), Du145 (IC₅₀ = 7.68 μg/mL), FTC133 (IC₅₀ = 6.01 μg/mL), 8505C (IC₅₀ = 7.84 μg/mL), and Caco-2 (IC₅₀ = 8.79 μg/mL) cell lines after 24 h and against the HT29 cell line after 48 h (IC₅₀ = 11.67 μg/mL). Furthermore, it revealed a more favorable safety profile than either its homologue, embelin, or doxorubicin. The set of optimal extraction parameters obtained may be utilized for scientific and industrial purposes to achieve the best rapanone yield. Moreover, this benzoquinone revealed a high cytotoxic activity with good selectivity.

Assessment of safety and health-benefits of Citrus hystrix DC. peel essential oil, with regard to its bioactive constituents in an in vitro model of physiological and pathological skin conditions

Citrus hystrix DC. peel essential oil (ChEO) has been reported to have many biological activities and is promoted for topical application. However, its effect on skin functioning has not yet been studied. This study aimed to evaluate its safety for normal skin cells as well as its potential activity against human melanoma. In addition, pro-inflammatory and anti-inflammatory activity was assessed, as well as inhibitory effects on important skin enzymes: tyrosinase and hyaluronidase. To better understand the complexity of the action of ChEO and the role of individual components, the study also included an evaluation of the activity of its main constituents: limonene, β-pinene, and terpinen-4-ol as well as two mixtures of these compounds, specially designed for this purpose: M1 in equal proportions (1:1:1) and M2 in proportions mimicking those found in the ChEO (2.6:1.7:1). The results showed that the essential oil of the C. hystrix peel, as well as its major components, was not cytotoxic to normal human skin cells representing various skin layers, namely keratinocytes (HaCaT), melanocytes (HEM), and fibroblasts (HDF), even after prolonged exposure of 72 h. The pro-inflammatory effect of ChEO, tested by caspase-1 activation in HaCaT cells, was less pronounced compared to limonene, β-pinene and terpinen-4-ol, and generally very low. On the other hand, its anti-inflammatory effect was noticeable and was half the potency of diclofenac sodium used as the reference drug. Although the anti-hyaluronidase activity of C. hystrix peel essential oil was lower compared to β-pinene and terpinen-4-ol, ChEO revealed fairly high anti-tyrosinase activity, with an enzyme inhibition level of over 80% at a concentration of 150-220 μg/ml. Studies on the potential anti-melanoma effect were performed using the LDH assay on three human cell lines of varying degrees of malignancy, namely WM793, A375, and HTB140. ChEO was more active than the tested single compounds or their mixtures. WM793 cells were found to be most susceptible, while HTB140 and A375 cells were slightly more resistant (IC₅₀ 59, 88 and 70 μg/ml, respectively). Our data indicate that ChEO is safe for the skin and has a perspective as an anti-melanoma agent.

Ultrasound-assisted deep eutectic solvents extraction of glabridin and isoliquiritigenin from Glycyrrhiza glabra: Optimization, extraction mechanism and in vitro bioactivities

Licorice (Glycyrrhiza glabra) is extensively used owing to the superior pharmacological effects. However, its maximum application potential has not been fully exploited due to the limitation of currently available extraction solvent and methods. In this study, an eco-friendly deep eutectic solvent (NADESs) based ultrasound-assisted extraction (DES-UAE) method was applied to prepare licorice extracts. The DES-UAE using choline chloride and lactic acid as solvent was optimized and modeled by using response surface methodology to maximize the extraction yields of glabridin (GLA) and isoliquiritigenin (ISL). The optimized extracts possessed higher contents of GLA and ISL than available extraction methods, and the enriched products showed superior pharmacological activities in vitro. Furthermore, scanning electron microscopy (SEM) and molecular dynamic simulation analyses were performed to deeply investigate the interaction between solvent and targeted compounds. This study not only provides an eco-friendly method for high-efficient extraction of GLA and ISL from licorice but also illustrates the mechanism of the increased extraction efficacy, which may contribute to the application of licorice and deep insight into extraction mechanism using DES.

Embelin: A novel XIAP inhibitor for the prevention and treatment of chronic diseases

Chronic diseases are a serious health concern worldwide, especially in the elderly population. Most chronic diseases like cancer, cardiovascular ailments, neurodegenerative disorders, and autoimmune diseases are caused due to the abnormal functioning of multiple signaling pathways that give rise to critical anomalies in the body. Although a lot of advanced therapies are available, these have failed to entirely cure the disease due to their less efficacy. Apart from this, they have been shown to manifest disturbing side effects which hamper the patient's quality of life to the extreme. Since the last few decades, extensive studies have been done on natural herbs due to their excellent medicinal benefits. Components present in natural herbs target multiple signaling pathways involved in diseases and therefore hold high potential in the prevention and treatment of various chronic diseases. Embelin, a benzoquinone, is one such agent isolated from Embelia ribes, which has shown excellent biological activities toward several chronic ailments by upregulating a number of antioxidant enzymes (e.g., SOD, CAT, GSH, etc.), inhibiting anti-apoptotic genes (e.g., TRAIL, XIAP, survivin, etc.), modulating transcription factors (e.g., NF-κB, STAT3, etc.) blocking inflammatory biomarkers (e.g., NO, IL-1β, IL-6, TNF-α, etc.), monitoring cell cycle synchronizing genes (e.g., p53, cyclins, CDKs, etc.), and so forth. Several preclinical studies have confirmed its excellent therapeutic activities against malicious diseases like cancer, obesity, heart diseases, Alzheimer's, and so forth. This review presents an overview of embelin, its therapeutic prospective, and the molecular targets in different chronic diseases.

Relationship between Maturity Stage, Triterpenoid Content and Cytotoxicity of Sorbus intermedia (EHRH.) PERS. Fruits - A Chemometric Approach

In this study, two ursane-type triterpenes, i. e., ursolic acid (UA) and 3-O-β-acetoxyursolic acid (AUA), were isolated and quantified in Sorbus intermedia (EHRH.) PERS. fruits. UA and AUA levels differed slightly throughout fruit maturation, and both triterpenes showed similar dynamics of accumulation with the highest levels found in ripe fruits (up to 6.33±0.56 and 1.17±0.18 mg/g dw. of UA and AUA, respectively). The extracts derived from unripe fruits displayed significant cytotoxic effects against WM793, DU-145, PC3, 8505C, Caco2 and A549 cells, but no correlation between UA and AUA levels and cytotoxicity was found. On the other hand, extracts from mature fruits were not active towards almost all of the tested cell lines. The chemometric approach showed that the extracts derived from fruits harvested earlier clustered to form a clearly distanced group from extracts prepared from more-mature fruits. The extracts at higher concentrations formed separate groups, which indicated the concentration-dependent effect of these extracts on the cells.

A Comparative Survey of Anti-Melanoma and Anti-Inflammatory Potential of Usnic Acid Enantiomers-A Comprehensive In Vitro Approach

Usnic acid (UA) is a chiral lichen metabolite with an interesting pharmacological profile. The aim of this study was to compare the anti-melanoma effect of (+)-UA and (−)-UA in an in vitro model by studying their impact on the cells as well as the processes associated with cancer progression. The effect of UA enantiomers on the viability, proliferation, and invasive potential of three melanoma cell lines (HTB140, A375, WM793) was evaluated. Their interaction with a chemotherapeutic drug—doxorubicin was assessed by isobolographic analysis. Anti-inflammatory and anti-tyrosinase properties of (+)-UA and (−)-UA were also examined. Both UA enantiomers dose- and time-dependently decreased the viability of all three melanoma cell lines. Their synergistic effect with doxorubicin was observed on A375 cells. (+)-Usnic acid at a sub-cytotoxic dose strongly inhibited melanoma cells migration. Both UA enantiomers decreased the release of pro-inflammatory mediators. The cytotoxic effect of (+)-UA and (−)-UA depends greatly on the melanoma cell type; however, the overall anti-melanoma potential is perspective. Our results indicate that the strategy of combining usnic acid enantiomers with cytostatic drugs may be an interesting option to consider in combating melanoma; however, further studies are required.

(+)-Usnic Acid as a Promising Candidate for a Safe and Stable Topical Photoprotective Agent

The study aimed to examine whether usnic acid—a lichen compound with UV-absorbing properties—can be considered as a prospective photoprotective agent in cosmetic products. Moreover, a comparison of two usnic acid enantiomers was performed to preselect the more effective compound. To meet this aim, an in vitro model was created, comprising the determination of skin-penetrating properties via skin-PAMPA assay, safety assessment to normal human skin cells (keratinocytes, melanocytes, fibroblasts), and examination of photostability and photoprotective properties. Both enantiomers revealed comparable good skin-penetrating properties. Left-handed usnic acid was slightly more toxic to keratinocytes (IC₅₀ 80.82 and 40.12 µg/mL, after 48 and 72 h, respectively) than its right-handed counterpart. The latter enantiomer, in a cosmetic formulation, was characterized by good photoprotective properties and photostability, comparable to the UV filter octocrylene. Perhaps most interestingly, (+)-usnic acid combined with octocrylene in one formulation revealed enhanced photoprotection and photostability. Thus, the strategy can be considered for the potential use of (+)-usnic acid as a UV filter in cosmetic products. Moreover, the proposed model may be useful for the evaluation of candidates for UV filters.

Serjanic Acid Glycosides from Chenopodium hybridum L. with Good Cytotoxicity and Selectivity Profile against Several Panels of Human Cancer Cell Lines

Two triterpene saponins, including a novel serjanic acid derivative, were isolated from Chenopodium hybridum L. (Amaranthaceae) aerial parts. Their structures were elucidated by a combination of spectroscopic methods (MS, 1D and 2D NMR). Both compounds were evaluated for cytotoxicity and selectivity on skin, prostate, gastrointestinal, thyroid and lung cancer cells. Their effect was dose and time-dependent with varied potency, the highest against prostate PC3 and melanoma WM793, where IC₅₀ was lower than the reference drug doxorubicin. Structure–activity relationship is briefly discussed.

Multidirectional anti-melanoma effect of galactolipids (MGDG-1 and DGDG-1) from Impatiens parviflora DC. and their synergy with doxorubicin

The anti-melanoma potential of galactolipids: MGDG-1 and DGDG-1, isolated from Impatiens parviflora, and their synergistic effect with anticancer drug - doxorubicin (DOX) was investigated. Both compounds demonstrated time- and dose-dependent cytotoxicity against human melanoma cells of different metastatic potential. MGDG-1 was more effective than DGDG-1, with the highest activity against A375 cell line (IC₅₀ = 15.14 μg/mL). Both compounds acted selectively, were devoid of hepatotoxicity or mutagenicity. Additionally, MGDG-1 proved to be a tyrosinase inhibitor. Co-administration of MGDG-1 and DGDG-1 with DOX revealed a synergistic cytotoxic effect on melanoma cells. The cytotoxicity of all tested MGDG-1/DOX and DGDG-1/DOX cocktails was considerably higher than that of each agent administered alone. MGDG-1/DOX (Mix3) reduced the viability of A375 melanoma cells almost totally and this effect was 2-fold more potent as compared to DOX alone. Our study indicates that the overall effect is enhanced with the increasing concentration of MGDG-1 in the cocktail. These results open up a possibility for lowering therapeutic doses of chemotherapeutics such as doxorubicin when co-administrated with galactolipids. Thus, MGDG-1 can be prospectively considered as multidirectional anti-melanoma agent and can be recommended for further in vitro and in vivo studies, especially in search for effective combined therapy.

Heliotropium indicum L.: From Farm to a Source of Bioactive Compounds with Therapeutic Activity

This study aimed to summarize the available data on the ethnomedicinal and phytopharmacological activities of Heliotropium indicum L. based on database reports. For this purpose, an up-to-date literature search was carried out in the Google Scholar, Scopus, Springer Link, Web of Science, ScienceDirect, ResearchGate, PubMed, Chem Spider, Elsevier, BioMed Central, and patent offices (e.g., USPTO, CIPO, NPI, Google patents, and Espacenet) for the published materials. The findings suggest that the plant contains many important phytochemicals, including pyrrolizidine alkaloids, indicine, echinitine, supinine, heleurine, heliotrine, lasiocarpine, acetyl indicine, indicinine, indicine N-oxide, cynoglossine, europine N-oxide, heleurine N-oxide, heliotridine N-oxide, heliotrine N-oxide, heliotrine, volatile oils, triterpenes, amines, and sterols. Scientific reports revealed that the herb showed antioxidant, analgesic, antimicrobial, anticancer, antituberculosis, antiplasmodial, anticataract, antifertility, wound healing, antiinflammatory, antinociceptive, antihyperglycemic, anthelmintic, diuretic, antitussive, antiglaucoma, antiallergic, and larvicidal activity. In conclusion, in vitro studies with animal models seem to show the potential beneficial effects of H. indicum against a wide variety of disorders and as a source of phytotherapeutic compounds. However, clinical studies are necessary to confirm the effects observed in animal models, determine the toxicity of the therapeutic dose and isolate the truly bioactive components.

Dragon Fruits as a Reservoir of Natural Polyphenolics with Chemopreventive Properties

Dragon fruits are a valued source of bioactive compounds with high potential to become a functional food. The aim of the study was to evaluate and compare the chemopreventive potential and chemical composition of fruits harvested in Thailand and Israel. The amount of different compounds in water and methanol extracts and antioxidant activity was investigated. Moreover, cytotoxic activity against cancer and normal cells of skin, prostate, and gastrointestinal origin was performed, accompanied by anti-inflammatory assay based on NO production in RAW 264.7 macrophage model. Additionally, the quenching properties of polyphenols from fruits were determined by the interaction of the main drug carrier in blood human serum (HSA). The chemometric analysis was used to reveal the relationships between the determined parameters. Dragon fruits harvested in Israel revealed higher antioxidant properties and total content of polyphenols and betacyanins when compared to those from Thailand. The examined fruits of both origins showed significant cytotoxic activity toward colon and prostate cancer cells, with no toxic effect on normal cells, but also no anti-inflammatory effect. Moreover, a high binding ability to HSA was observed for water extracts of dragon fruits. All these predestine dragon fruits are the candidates for the attractive and chemopreventive elements of daily diet.