The effect of aloe emodin on the proliferation of a new merkel carcinoma cell line

Spectroscopic characterization of different protonation/deprotonation states of Barbaloin in aqueous solution

Barbaloin (10-glucopyranosyl-1,8-dihydroxy-3-(hydroxymethyl)-9(10H)-anthraquinone: aloin A), present in Aloe species, is widely used in food, cosmetic and pharmaceutical industries. Here we characterize its optical absorption and emission spectra in aqueous solution at different pH values. Through pH titration, using both absorption and fluorescence spectroscopy, two pK_a values for Barbaloin were determined: pK_a1=9.6±0.6 and pK_a2=12.6±0.8. These acidity constants were found to be higher than those found for Emodin, a similar molecule which lacks the sugar moiety present in Barbaloin. Performing quantum mechanical calculations for non-ionized, singly, doubly, and triply deprotonated forms of Barbaloin in vacuum and in water, we assigned the positions of the site for the first and third deprotonation in the anthraquinone group, and the second deprotonation in the glucose group. The instability of Barbaloin in high pH solutions is discussed here, and the optical absorption and fluorescence spectra due to products resulted from Barbaloin degradation at high pH is well separated from the Barbaloin original spectra. Biological fluids have specific pH values to maintain homeostasis, hence determining the pK_a of Barbaloin is important to evaluate the mechanism of action of this drug in different parts of an organism as well as to predict pharmacological relevant parameters, such as absorption, distribution, metabolism, and excretion.

Emodin coupled with high LET neutron beam-a novel approach to treat on glioblastoma

The primary motivation of this investigative study is trying to find an alternative treatment that can be used to slow down or treat glioblastoma due to the witnessed toxic side effects of the current drugs coupled with limited effectiveness in overall treatment. Consequently, a Chinese plant extract emodin proves to play a critical role in this investigative study since results from the Western blot and the other accompanying assays for anti-cancer effects indicate that it cannot work a lot to suppress cell migration and possible invasion, but rather emodin can be combined with radiation to give desired outcomes. Our result shows that the kind of radiation which acts well with emodin is neutron radiation rather than gamma radiation. Emodin significantly enhanced the radiosensitivity of LN18 and LN428 cells to γ-rays through MTT assay and cell counting. Accordingly, exposure to neutron radiation in the presence of emodin induced apoptotic cell death and autophagic cell death to a significantly higher extent, and suppressed cell migration and invasiveness more robustly. These effects are presumably due to the ability of emodin to amplify the effective dose from neutron radiation more efficiently. Thus, the study below is one such trial towards new interventional discovery and development in relation to glioblastoma treatment.

Advances in Understanding the Role of Aloe Emodin and Targeted Drug Delivery Systems in Cancer

Cancer is one of the important causes of death worldwide. Despite remarkable improvements in cancer research in the past few decades, several cancer patients still cannot be cured owing to the development of drug resistance. Natural sources might have prominence as potential drug candidates. Among the several chemical classes of natural products, anthraquinones are characterized by their large structural variety, noticeable biological activity, and low toxicity. Aloe emodin, an anthraquinone derivative, is a natural compound found in the roots and rhizomes of many plants. This compound has proven its antineoplastic, anti-inflammatory, antiangiogenic, and antiproliferative potential as well as ability to prevent cancer metastasis and potential in reversing multidrug resistance of cancer cells. The anticancer property of aloe emodin, a broad-spectrum inhibitory agent of cancer cells, has been detailed in many biological pathways. In cancer cells, these molecular mechanisms consist of inhibition of cell growth and proliferation, cell cycle arrest deterioration, initiation of apoptosis, antimetastasis, and antiangiogenic effect. In accordance with the strategy of developing potential drug candidates from natural products, aloe emodin's low bioavailability has been tried to be overcome by structural modifications and nanocarrier systems. Consequently, this review summarizes the antiproliferative and anticarcinogenic properties of aloe emodin, as well as the enhanced activity of its derivatives and the advantages of drug delivery systems on bioavailability.

Aloe and its Effects on Cancer: A Narrative Literature Review

Many years ago, Aloe Vera was cited to have a lot of therapeutic properties including; anti-microbial, anti-viral, anti-cancer, anti-oxidant, anti-inflammatory, skin protection, wound healing, and regulation of blood glucose and cholesterol. However, Aloe could present some side effects. This review focused on the latest discoveries regarding the therapeutic role of Aloe plant or its compounds on the acquired biological capabilities for tumour growth and progression namely; evading growth suppressor, avoiding immune destruction, enabling replicative immortality, tumour promoting inflammation, activating invasion and metastasis, inducing angiogenesis, genome instability and mutation, resisting cell death, deregulating cellular energetics and sustaining proliferating signalling. It clarified the anti-cancer activities it exerts on different types of cancer and also highlighted some pro-oncogenic pathways that can be disrupted by different compounds of Aloe.

Treatment of Skin Disorders with Aloe Materials

The skin is the largest organ and functions as a barrier to protect the underlying tissues against the elements and pathogens, while also fulfilling many physiological roles and biochemical functions such as preventing excessive water loss. Skin disorders vary greatly in terms of origin, severity, symptoms and affect persons of all ages. Many plants have been used for medicinal purposes since ancient times including the treatment of skin disorders and diseases. Aloe represents one of the earliest medicinal plant species mentioned in antique scriptures and even in rock art dating back thousands of years. Different Aloe species and materials have been used in the prevention and treatment of skin related disorders. Aloe vera is the most commonly used Aloe species for medicinal purposes. Some of the most prominent skin related applications and disorders that Aloe materials have been investigated for are discussed in this paper, which include cosmetic, radiation, cancer, wound and antimicrobial applications. Both in vitro and in vivo studies are included in the discussions of this paper and comprehensive summaries of all these studies are given in tables in each section. Although some contradictory results were obtained among studies, certain Aloe materials have shown excellent efficacy and exhibited potential for the treatment of skin related disorders and cosmetic applications.

New Z-chalcones obtained from aloe-emodin: Synthesis, characterization and photophysical properties

Three new Z-chalcone derivatives were synthesized under stereoselective conditions by condensation between an aldehyde derivative (prepared from aloe-emodin) and an acetophenone, using potassium hydroxide in dimethyl sulfoxide/H2O at room temperature. The Z configuration of the chalcone derivatives was established by nuclear magnetic resonance (NMR) studies. Photophysical properties related to the UV-Vis absorption/emission spectra and molar extinction coefficients (ε) in different solvents were determined.

Chinese herbal medicines as a source of molecules with anti-enterovirus 71 activity

Enterovirus 71 (EV71) is one of the causative agents of hand, foot, and mouth disease (HFMD), which sometimes leads to severe neurological disease and death in the Asia-Pacific region. In Chinese medicine, HFMD is caused mainly by an accumulation of damp-heat and toxicity in the body. No effective drugs are currently available for the treatment and prevention of EV71 infection. This review summarizes the potential Chinese herbal extracts and isolated compounds with antiviral activity against EV71 and their clinical applications, especially those categorized as heat-clearing and detoxifying.

Aloe-Emodin Protects RIN-5F (Pancreatic β-cell) Cell from Glucotoxicity via Regulation of Pro-Inflammatory Cytokine and Downregulation of Bax and Caspase 3

To determine the protective effect of aloe-emodin (AE) from high glucose induced toxicity in RIN-5F (pancreatic β-cell) cell and restoration of its function was analyzed. RIN-5F cells have been cultured in high glucose (25 mM glucose) condition, with and without AE treatment. RIN-5F cells cultured in high glucose decreased cell viability and increased ROS levels after 48 hr compared with standard medium (5.5 mM glucose). Glucotoxicity was confirmed by significantly increased ROS production, increased pro-inflammatory (IFN-γ, IL-1β,) & decreased anti-inflammatory (IL-6&IL-10) cytokine levels, increased DNA fragmentation. In addition, we found increased Bax, caspase 3, Fadd, and Fas and significantly reduced Bcl-2 expression after 48 hr. RIN-5F treated with both high glucose and AE (20 μM) decreased ROS generation and prevent RIN-5F cell from glucotoxicity. In addition, AE treated cells cultured in high glucose were transferred to standard medium, normal responsiveness to glucose was restored within 8hr and normal basal insulin release within 24 hr was achieved when compared to high glucose.

Expression profile of genes modulated by Aloe emodin in human U87 glioblastoma cells

Glioblastoma, the most aggressive and malignant form of glioma, appears to be resistant to various chemotherapeutic agents. Hence, approaches have been intensively investigated to targeti specific molecular pathways involved in glioblastoma development and progression. Aloe emodin is believed to modulate the expression of several genes in cancer cells. We aimed to understand the molecular mechanisms underlying the therapeutic effect of Aloe emodin on gene expression profiles in the human U87 glioblastoma cell line utilizing microarray technology. The gene expression analysis revealed that a total of 8,226 gene alterations out of 28,869 genes were detected after treatment with 58.6 μg/ml for 24 hours. Out of this total, 34 genes demonstrated statistically significant change (p<0.05) ranging from 1.07 to 1.87 fold. The results revealed that 22 genes were up-regulated and 12 genes were down-regulated in response to Aloe emodin treatment. These genes were then grouped into several clusters based on their biological functions, revealing induction of expression of genes involved in apoptosis (programmed cell death) and tissue remodelling in U87 cells (p<0.01). Several genes with significant changes of the expression level e.g. SHARPIN, BCAP31, FIS1, RAC1 and TGM2 from the apoptotic cluster were confirmed by quantitative real-time PCR (qRT-PCR). These results could serve as guidance for further studies in order to discover molecular targets for the cancer therapy based on Aloe emodin treatment.

Natural products as potential cancer therapy enhancers: A preclinical update

Cancer is a multifactorial disease that arises as a consequence of alterations in many physiological processes. Recently, hallmarks of cancer were suggested that include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis, along with two emerging hallmarks including reprogramming energy metabolism and escaping immune destruction. Treating multifactorial diseases, such as cancer with agents targeting a single target, might provide partial treatment and, in many cases, disappointing cure rates. Epidemiological studies have consistently shown that the regular consumption of fruits and vegetables is strongly associated with a reduced risk of developing chronic diseases, such as cardiovascular diseases and cancer. Since ancient times, plants, herbs, and other natural products have been used as healing agents. Moreover, the majority of the medicinal substances available today have their origin in natural compounds. Traditionally, pharmaceuticals are used to cure diseases, and nutrition and herbs are used to prevent disease and to provide an optimal balance of macro- and micro-nutrients needed for good health. We explored the combination of natural products, dietary nutrition, and cancer chemotherapeutics for improving the efficacy of cancer chemotherapeutics and negating side effects.

Cancer Prevention and Therapy: Integrating Traditional Korean Medicine Into Modern Cancer Care

In spite of billions of dollars spent on cancer research each year, overall cancer incidence and cancer survival has not changed significantly in the last half century. Instead, the recent projection from the World Health Organization suggests that global cancer incidence and death is expected to double within the next decade. This requires an "out of the box" thinking approach. While traditional medicine used for thousands of years is safe and affordable, its efficacy and mechanism of action are not fully reported. Demonstrating that traditional medicine is efficacious and how it works can provide a "bed to bench" and "bench to bed" back approach toward prevention and treatment of cancer. This current review is an attempt to describe the contributions of traditional Korean medicine (TKM) to modern medicine and, in particular, cancer treatment. TKM suggests that cancer is an outcome of an imbalance of body, mind, and spirit; thus, it requires a multimodal treatment approach that involves lifestyle modification, herbal prescription, acupuncture, moxibustion, traditional exercise, and meditation to restore the balance. Old wisdoms in combination with modern science can find a new way to deal with the "emperor of all maladies."

Cell-type dependent response of melanoma cells to aloe emodin

Intrinsic characteristics of melanoma cells such as expression of inducible nitric oxide synthase (iNOS), redox status, and activity of signaling pathways involved in proliferation, differentiation and cell death define the response of the cells to the diverse treatments. In this context we compared the effectiveness of herbal antaquinone aloe emodin (AE) against mouse B16 melanoma and human A375, different in initial activity of ERK1/2, constitutive iNOS expression and basal level of reactive oxygen species (ROS). Both cell lines are sensitive to AE treatment. However, while the agent induces differentiation of B16 cells toward melanocytes, in A375 cells promoted massive apoptosis. Differentiation of B16 cells, characterized by enhanced melanin production and tyrosinase activity, was mediated by H(2)O(2) production synchronized with rapid p53 accumulation and enhanced expression of cyclins D1 and D3. Caspase mediated apoptosis triggered in A375 cells was accompanied with Bcl-2 but not iNOS down-regulation. In addition, opposite regulation of Akt-ERK1/2 axis in AE treated B16 and A375 cells correlated with different outcome of the treatment. However, AE in a dose-dependent manner rescued both B16 and A375 cells from doxorubicin- or paclitaxel-induced killing. These data indicate that caution is warranted when AE is administrated to the patients with conventional chemotherapy.

Aloe-emodin inhibits adipocyte differentiation and maturation during in vitro human mesenchymal stem cell adipogenesis

In this study, we examined the effects of Aloe-emodin (AE) on the inhibition of adipocyte differentiation during 3-isobutyl-1-methylxanthine (IBMX)-induced adipocyte differentiation in human mesenchymal stem cells (hMSCs). AE treatment (5, 10, and 20 µM) of preadipocyte cells resulted in a significant (p < 0.05) decrease in glycerol phosphate dehydrogenase and triglyceride levels as well as an increase in lactate dehydrogenase activity and attenuated lipid accumulation compared with untreated differentiated adipocytes. Using quantitative reverse transcription polymerase chain reaction, we studied the mRNA expression levels of resistin, adiponectin, aP(2), lipoprotein lipase, PPARγ, and tumor necrosis factor-α in hMSCs undergoing adipocyte differentiation; treatment with AE decreased the expression of these adipogenic genes and decreased adipocyte differentiation. In addition, AE suppresses the differentiation of hMSCs into adipocytes by downregulating PPARγ and C/EBPα expressions. AE significantly inhibited hMSCs proliferation and preadipocyte differentiation within the first 2 days of treatment, indicating that the antiadipogenic effect.

Merkel Cells, Normal and Neoplastic: An Update

Merkel cells (MC) occur in the basal epidermal layer, hair follicles, and oral mucosa, as complexes with sensory axons. The axons transduce slowly adapting type I mechanoreception, and MC modulate their sensitivity. MC also determine and maintain the 3-dimensional epidermal structure. They have neuroendocrine granules, rigid spinous processes, and desmosomal junctions with each other and with keratinocytes. Rare MC are dermaWl. Current evidence supports a basal cell origin. Merkel cell carcinomas (MCC) occur mostly in sun-exposed skin in old age. Trabecular, intermediate, or small cell in pattern, MCC have neuroendocrine granules, intercellular junctions, rigid spinous processes, and a paranuclear collection of intermediate filaments staining for cytokeratin 20. Most MCC behave indolently, but those with the small cell pattern, and some with the intermediate pattern, are aggressive and rapidly fatal.

Final report on the safety assessment of AloeAndongensis Extract, Aloe Andongensis Leaf Juice,aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Arborescens Leaf Protoplasts, Aloe Barbadensis Flower Extract, Aloe Barbadensis Leaf, Aloe Barbadensis Leaf Extract, Aloe Barbadensis Leaf Juice,aloe Barbadensis Leaf Polysaccharides, Aloe Barbadensis Leaf Water, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice Extract

Plant materials derived from the Aloe plant are used as cosmetic ingredients, including Aloe Andongensis Extract, Aloe Andongensis Leaf Juice, Aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Arborescens Leaf Protoplasts, Aloe Barbadensis Flower Extract, Aloe Barbadensis Leaf, Aloe Barbadensis Leaf Extract, Aloe Barbadensis Leaf Juice, Aloe Barbadensis Leaf Polysaccharides, Aloe Barbadensis Leaf Water, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice Extract. These ingredients function primarily as skin-conditioning agents and are included in cosmetics only at low concentrations. The Aloe leaf consists of the pericyclic cells, found just below the plant's skin, and the inner central area of the leaf, i.e., the gel, which is used for cosmetic products. The pericyclic cells produce a bitter, yellow latex containing a number of anthraquinones, phototoxic compounds that are also gastrointestinal irritants responsible for cathartic effects. The gel contains polysaccharides, which can be acetylated, partially acetylated, or not acetylated. An industry established limit for anthraquinones in aloe-derived material for nonmedicinal use is 50 ppm or lower. Aloe-derived ingredients are used in a wide variety of cosmetic product types at concentrations of raw material that are 0.1% or less, although can be as high as 20%. The concentration of Aloe in the raw material also may vary from 100% to a low of 0.0005%. Oral administration of various anthraquinone components results in a rise in their blood concentrations, wide systemic distribution, accumulation in the liver and kidneys, and excretion in urine and feces; polysaccharide components are distributed systemically and metabolized into smaller molecules. aloe-derived material has fungicidal, antimicrobial, and antiviral activities, and has been effective in wound healing and infection treatment in animals. Aloe barbadensis (also known as Aloe vera)-derived ingredients were not toxic in acute oral studies using mice and rats. In parenteral studies, the LD(50) using mice was > 200 mg/kg, rats was > 50 mg/kg, and using dogs was > 50 mg/kg. In intravenous studies the LD(50) using mice was > 80 mg/kg, rats was > 15 mg/kg, and dogs was > 10 mg/kg. The 14-day no observed effect level (NOEL) for the Aloe polysaccharide, acemannan, in the diet of Sprague-Dawley rats, was 50,000 ppm or 4.1 to 4.6 g/kg day(-1). In a 3-month study using mice, Aloe vera (extracted in ethanol) given orally in drinking water at 100 mg/kg produced reproductive toxicity, inflammation, and mortality above that seen in control animals. Aloe vera extracted in methanol and given to mice at 100 mg/kg in drinking water for 3 months caused significant sperm damage compared to controls. Aloe barbadensis extracted with water and given to pregnant Charles Foster albino rats on gestational days (GDs) 0 through 9 was an abortifacient and produced skeletal abnormalities. Both negative and positive results were found in bacterial and mammalian cell genotoxicity assays using Aloe barbadensis-derived material, Aloe Ferox-derived material, and various anthraquinones derived from Aloe. Aloin (an anthraquinone) did not produce tumors when included in the feed of mice for 20 weeks, nor did aloin increase the incidence of colorectal tumors induced with 1,2-dimethylhydrazine. Aloe-emodin (an anthraquinone) given to mice in which tumor cells had been injected inhibited growth of malignant tumors. Other animal data also suggest that components of Aloe inhibit tumor growth and improve survival. Various in vitro assays also demonstrated anticarcinogenic activity of aloe-emodin. Diarrhea was the only adverse effect of note with the use of Aloe-derived ingredients to treat asthma, ischemic heart disease, diabetes, ulcers, skin disease, and cancer. Case reports include acute eczema, contact urticaria, and dermatitis in individuals who applied Aloe-derived ingredients topically. The Cosmetic Ingredient Review Expert Panel concluded that anthraquinone levels in the several Aloe Barbadensis extracts are well understood and can conform to the industry-established level of 50 ppm. Although the phototoxicity anthraquinone components of Aloe plants have been demonstrated, several clinical studies of preparations derived from Aloe barbadensis plants demonstrated no phototoxicity, confirming that the concentrations of anthraquinones in such preparations are too low to induce phototoxicity. The characterization of aloe-derived ingredients from other species is not clear. In the absence of well-characterized derivatives, biological studies of these materials are considered necessary. The studies needed are 28-day dermal toxicity studies on Aloe Andongensis Extract, Aloe Andongensis Leaf Juice, Aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice (ingredients should be tested at current use concentrations). In Aloe-derived ingredients used in cosmetics, regardless of species, anthraquinone levels should not exceed 50 ppm. The Cosmetic Ingredient Review Expert Panel advised the industry that the total polychlorobiphenyl (PCB)/pesticide contamination of any plant-derived cosmetic ingredient should be limited to not more than 40 ppm, with not more than 10 ppm for any specific residue and that limits were appropriate for the following impurities: arsenic (3 mg/kg maximum), heavy metals (20 mg/kg maximum), and lead (5 mg/kg maximum).

Targeting angiogenesis with integrative cancer therapies

An integrative approach for managing a patient with cancer should target the multiple biochemical and physiological pathways that support tumor development while minimizing normal tissue toxicity. Angiogenesis is a key process in the promotion of cancer. Many natural health products that inhibit angiogenesis also manifest other anticancer activities. The authors will focus on natural health products (NHPs) that have a high degree of antiangiogenic activity but also describe some of their many other interactions that can inhibit tumor progression and reduce the risk of metastasis. NHPs target various molecular pathways besides angiogenesis, including epidermal growth factor receptor (EGFR), the HER-2/neu gene, the cyclooxygenase-2 enzyme, the NF-kB transcription factor, the protein kinases, Bcl-2 protein, and coagulation pathways. The herbalist has access to hundreds of years of observational data on the anticancer activity of many herbs. Laboratory studies are confirming the knowledge that is already documented in traditional texts. The following herbs are traditionally used for anticancer treatment and are antiangiogenic through multiple interdependent processes that include effects on gene expression, signal processing, and enzyme activities: Artemisia annua (Chinese wormwood), Viscum album (European mistletoe), Curcuma longa (turmeric), Scutellaria baicalensis (Chinese skullcap), resveratrol and proanthocyanidin (grape seed extract), Magnolia officinalis (Chinese magnolia tree), Camellia sinensis (green tea), Ginkgo biloba, quercetin, Poria cocos, Zingiber officinale (ginger), Panax ginseng, Rabdosia rubescens (rabdosia), and Chinese destagnation herbs. Quality assurance of appropriate extracts is essential prior to embarking on clinical trials. More data are required on dose response, appropriate combinations, and potential toxicities. Given the multiple effects of these agents, their future use for cancer therapy probably lies in synergistic combinations. During active cancer therapy, they should generally be evaluated in combination with chemotherapy and radiation. In this role, they act as biological response modifiers and adaptogens, potentially enhancing the efficacy of the so-called conventional therapies. Their effectiveness may be increased when multiple agents are used in optimal combinations. New designs for trials to demonstrate activity in human subjects are required. Although controlled trials might be preferred, smaller studies with appropriate end points and surrogate markers for antiangiogenic response could help prioritize agents for the larger resource-intensive phase 3 trials.

Cosmeceuticals Containing Herbs: Fact, Fiction, and Future

BACKGROUND

Modern medicine is rooted in ethnobotanical traditions using indigenous flora to treat symptoms of human diseases or to improve specific aspects of the body condition. Herbal medicine is now used by over half of the American population. Yet the American medical community generally lacks knowledge of the function, metabolism, interaction, adverse reactions, and preparation of herbal products.

OBJECTIVE

Because over 60 botanicals are marketed in cosmeceutical formulations, dermatologists need to obtain working knowledge of the major botanicals. The preparation, traditional uses, mechanisms of action, human clinical data, adverse reactions, and interactions all impact herbal efficacy and are discussed below.

METHOD

English-language medical journal and symposium searches.

RESULTS

The most important botanicals pertaining to dermatologic uses, such as cosmeceuticals, include teas, soy, pomegranate, date, grape seed, Pycnogenol, horse chestnut, German chamomile, curcumin, comfrey, allantoin, and aloe. All are documented to treat dermatologic conditions. Only green and black tea, soy, pomegranate, and date have published clinical trials for the treatment of parameters of extrinsic aging.

CONCLUSIONS

Preparation of botanical-based cosmeceuticals is complex. Very few of these products are supported by evidence-based science.

Aloe-emodin modulates PKC isozymes, inhibits proliferation, and induces apoptosis in U-373MG glioma cells

Aloe-emodin (1,8-dihydroy-3-[hydroxymethyl]-anthraquione) purified from Aloe vera leaves has been reported to have antitumor activity. The objectives of our research were to determine how aloe-emodin regulates the cell cycle, cell proliferation and protein kinase C (PKC) during glioma growth and development. To establish the cell cycle effects of aloe-emodin on brain cells [transformed glia cell line (SVG) and human glioma U-373MG cell line (U-373MG)], cells were treated with either dimethylsulfoxide (DMSO; control) or aloe-emodin (40 microM). Results from flow cytometry demonstrated that aloe-emodin delayed the number of cells entering and exiting DNA synthesis (S) phase in both SVG and U-373MG cells indicating that aloe-emodin may inhibit S phase progression. Assessment of cell viability demonstrated that SVG and U-373MG glioma cell were highly sensitive to aloe-emodin. The aloe-emodin-induced decreased proliferation was sustained at 48-96 h. A PKC activity assay was quantified to establish the role of PKC in aloe-emodin's mode of action. Exposure of SVG and U-373MG glioma cells to aloe-emodin suppressed PKC activity and reduced the protein content of most of the PKC isozymes. We determined that cancer growth inhibition by aloe-emodin was due to apoptosis (i.e., programmed cell death). Taken together, these results support the hypothesis that aloe-emodin represents a novel antitumor chemotherapeutic drug.

High-performance liquid chromatographic assay for the determination of Aloe Emodin in mouse plasma

An isocratic high-performance liquid chromatography (HPLC) method was developed and validated to determine Aloe Emodin (AE) in mouse plasma. The analysis required 0.3 ml of plasma and involves extraction with dichloromethane. The HPLC separation was carried out on Symmetry Shield RP18, a mobile phase of methanol-water-acetic acid (65:35:0.2) and fluorescence detection at lambda(ex)=410 nm and lambda(em)=510 nm. The retention time of AE was 11.7 min. The assay was linear from 10 to 1,000 ng/ml (r2 > or = 0.999), showed intra- and inter-day precision within 7.8 and 4.7%, and accuracy of 87.3-105.7%. Detection limit (LOD) and quantification limit (LOQ) were 4.5 and 5 ng/ml, respectively. The method was applied to determine for the first time the pharmacokinetic of AE in mice.

Effects of Aloe vera on gap junctional intercellular communication and proliferation of human diabetic and nondiabetic skin fibroblasts

OBJECTIVE

To evaluate the effects of Aloe vera on gap junctional intercellular communication (GJIC) and proliferation of human skin fibroblasts in the presence or absence of basic fibroblast growth factor (FGF-2).

DESIGN

In vitro study using human type II diabetic and nondiabetic skin fibroblast cell lines.

SETTING AND SUBJECTS

Diabetic (n = 4) and nondiabetic (n = 4) human skin fibroblast cell lines were purchased from Coriell Institute for Medical Research (Camden, NJ). The cells were cultured with or without Aloe vera extract in increasing concentrations (0%, 0.625%, 1.25%, 2.5%, 5%, 10%, and 20%; v/v) in culture medium and with or without FGF-2 (30 ng/mL).

MEASUREMENTS

GJIC was evaluated after 48-hour incubation with treatments by laser cytometry. Cells were counted after 72-hour incubation with treatments by using a Coulter counter.

RESULTS

The rate of GJIC was greater (p < 0.01) for diabetic than for nondiabetic fibroblasts (3.5 +/- 0.1 versus 3.0 +/- 0.1% per minute during the first 4 minutes after photobleaching). GJIC was increased ( p < 0.05) for diabetic fibroblasts in the presence of 2.5% and 5% of Aloe vera extract (4.2 +/- 0.1 and 4.0 +/- 0.2 versus 3.5 +/- 0.1% per minute for control, respectively). FGF-2 stimulated (p < 0.01) GJIC for diabetic (4.0 +/- 0.1 versus 3.5 +/- 0.1% per minute for control) and nondiabetic (3.5 +/- 0.1 versus 3.0 +/- 0.1% per minute for control) fibroblasts. Aloe vera extract did not affect GJIC of nondiabetic fibroblast cultured without FGF-2. However, Aloe vera extract decreased (p < 0.05) FGF-2 stimulatory effects on GJIC of diabetic and nondiabetic fibroblasts. Proliferation of diabetic fibroblasts was increased (p < 0.05) by 1.25% and 2.5% Aloe vera extract in medium. Proliferation of nondiabetic fibroblasts was not affected by Aloe vera extract. FGF-2 increased (p < 0.05) proliferation of nondiabetic fibroblasts and FGF-2 did not affect proliferation of diabetic fibroblasts. Aloe vera extract decreased (p < 0.05) FGF-2 stimulatory effects on proliferation of nondiabetic fibroblasts.

CONCLUSIONS

These data demonstrate that Aloe vera has the ability to stimulate GJIC and proliferation of human skin fibroblasts in diabetes mellitus. Furthermore, these results indicate that Aloe vera contains a compound(s) that neutralizes, binds with FGF-2 receptor, or otherwise alters signaling pathways for FGF-2. By affecting both GJIC and proliferation of diabetic fibroblasts, Aloe vera may improve wound healing in diabetes mellitus.

In vitro studies on the photobiological properties of aloe emodin and aloin A

Plants containing aloin A, aloe emodin, and structurally related anthraquinones have long been used as traditional medicines and in the formulation of retail products such as laxatives, dietary supplements, and cosmetics. Since a recent study indicated that topically applied aloe emodin increases the sensitivity of skin to UV light, we examined the events following photoexcitation of aloin A and aloe emodin. We determined that incubation of human skin fibroblasts with 20 microM aloe emodin for 18 h followed by irradiation with UV or visible light resulted in significant photocytotoxicity. This photocytotoxicity was accompanied by oxidative damage in both cellular DNA and RNA. In contrast, no photocytotoxicity was observed following incubation with up to 500 microM aloin A and irradiation with UVA light. In an attempt to explain the different photobiological properties of aloin A and aloe emodin, laser flash photolysis experiments were performed. We determined that the triplet state of aloe emodin was readily formed following photoexcitation. However, no transient intermediates were formed following photoexcitation of aloin A. Therefore, generation of reactive oxygen species and oxidative damage after irradiation of aloin A is unlikely. Although aloin A was not directly photocytotoxic, we found that human skin fibroblasts can metabolize aloin A to aloe emodin.