From the Cover: Aloin, a Component of the Aloe Vera Plant Leaf, Induces Pathological Changes and Modulates the Composition of Microbiota in the Large Intestines of F344/N Male Rats

Aloe Barbadensis Miller (Aloe Vera)

Aloe Barbadensis Miller (Aloe Vera, AV) is a widely recognized for its diverse health-promoting, skin care, and medicinal properties. This narrative review provides a comprehensive overview of AV's bioactive compounds, pharmacological activities, potential applications, its toxic and adverse effects, as well as the clinical evidence supporting AV's efficacy in disease prevention. AV contains over 200 bioactive compounds, with the inner clear gel of the leaves containing the majority of these compounds. These include phenolic acids (274.5-307.5 mg/100 g), flavonoids. (3.63-4.70 g/kg), polysaccharides (3.82-6.55 g/kg), saponins, alkaloids, terpenoids, and anthraquinone derivatives. Findings from clinical studies involving both humans and animals highlight the therapeutic potential of AV across diverse health domains. The studies demonstrate AV's efficacy in reducing blood glucose levels, exhibiting antioxidant and immunomodulatory effects, inducing apoptosis in cancer cells, protecting the liver from damage, and displaying antimicrobial properties. In the fields of dermatology and dentistry, AV has also been observed to promote skin and oral health. However, it is imperative to acknowledge potential risks, adhere to recommended dosages, and seek guidance from healthcare experts before employing AV as a natural therapeutic option. Moreover, considering safety concerns, further well-designed randomized controlled trials are necessary to substantiate the potential benefits of AV and comprehensively assess any associated risks.

Application of the herbal chemical marker ranking system (Herb MaRS) to the standardization of herbal raw materials: a case study

INTRODUCTION

Phytochemical standardization of herbal materials involves establishing consistent levels of one or more active ingredients or markers. It ensures the authenticity and quality of herbal materials, extracts, and their products. This research aimed to apply the herbal chemical marker ranking system (Herb MaRS) originally proposed for quality assurance of complex herbal products to establish markers for controlling the quality of herbal raw materials.

METHODS

The assessment of compounds for suitability as markers was based on the Herb MaRS, with minor modifications as follows: for more objective scoring, evidence of biological activity of the potential marker compound(s) was determined at three levels based on the number of symptoms of the disease condition a compound can treat or alleviate: (i) one symptom (1 point), two symptoms (2 points), and 3 or more symptoms (3 points). The reported concentrations of the compounds were also scored as follows: concentration not determined (0 points), concentration ≥ 5 ppm (1 point), concentration ≥ 50 ppm (2 points) and availability of analytical standards (1 point). Finally, the compounds were scored for the availability of an analytical method (1 point). The compounds were scored from 0 to 8, where 8 indicated the most suitable chemical marker.

RESULTS

The selected markers were as follows: aromadendrine, α-terpineol, globulol, and 1,8-cineol (in Eucalyptus globulus Labill. ); aloin, aloe emodin, acemannan (in Aloe barbadensis (L.) Burm.f. ), lupeol, lupenone, betulinic acid, betulin, and catechin (in Albizia coriaria Oliv.); mangiferin, catechin, quercetin, and gallic acid (in Mangifera indica L.); polygodial (in Warburgia ugandensis Sprague); azadirachtin, nimbin, nimbidin (in Azadirachta indica A. Juss. ); and 6,8,10-gingerols, and 6-shogaol (in Zingiber officinalis Roscoe).

CONCLUSIONS

Herb MaRS can be efficiently applied to select marker compounds for quality control of herbal materials. However, for herbs whose phytochemicals have not been sufficiently researched, it is difficult to establish evidence of activity, and there are no analytical standards and/or methods; this is the case for plants exclusively used in Africa. The markers identified should be incorporated into chromatographic fingerprints, their quantitative methods developed, and evaluated for applicability at the various stages of the production chain of herbal medicines; then, they can be included in future local plant monographs. There is also a need to build local capacity to isolate marker compounds, particularly those that are not sold by current vendors.

Microbiota-derived short chain fatty acids in fermented Kidachi Aloe promote antimicrobial, anticancer, and immunomodulatory activities

BACKGROUND

Fermented Aloe leaf juice is a commonly used food supplement in Japan. In a previous study, fermentation of A. arborescence juice was performed and the presence of short-chain fatty acids (SCFAs) was confirmed and quantified. Samples were collected before and after the fermentation process to be subjected, in the present study, to DNA extraction, 16S rRNA gene (V3-V4 regions) amplification, and sequencing by the next-generation Illumina MiSeq sequencer. Our work aims to analyze the sequences to assess the bacterial diversity in the juice before and after fermentation, identify the beneficial microbes responsible for the production of SCFAs, and evaluate some of the biological activities of the fermented juice.

RESULTS

Data revealed the richness and diversity of the bacterial community in the fermented juice compared to the unfermented control. Relative abundance of bacterial phyla showed that the majority of the microbial community in the test samples corresponded to Pseudomonadota (unfermented; 10.4%, fermented; 76.36%), followed by Bacillota (unfermented; 4.71%, fermented; 17.13%) and then Bacteroidota (unfermented; 0.57%, fermented; 1.64%). For the fermented sample, 84% of Bacillota were lactobacilli. A hierarchically clustered heatmap revealed that Lactobacillus was the most abundant genus in both samples suggesting its involvement in the production of SCFAs. To assess potential health benefits, the anticancer efficacy of the fermented product of A. arborescens was investigated against colorectal cancer (IC50 = 3.5 µg/ml) and liver cancer (IC50 = 6.367 µg/ml) compared to the normal peripheral blood mononuclear cells (PBMCs). Flow cytometric analysis of the cell cycle pattern revealed remarkable population arrest in G0 and G1, however, the highest percentages were mainly in the G1 phase for Hep-G2 (40.1%) and HCT-116 (53.2%) cell lines. This effect was accompanied by early apoptotic profiles of HCT-116 (36.9%) and late apoptosis for Hep-G2 (17.3%). Furthermore, immunomodulatory properties demonstrated a significantly (p < 0.001) reduced percentage of induced TNF-α while enhancing IFN-γ dramatically. For antimicrobial activities, marked broad-spectrum activities were recorded against some bacterial and fungal pathogens (17-37 mm inhibition zone diameter range).

CONCLUSION

Therefore, this study affords the basis of bacterial community composition in fermented A. arborescens juice as well as its potential biological benefits.

The absence of genotoxicity of Aloe vera beverages: A review of the literature

Aloe has a long history of topical and systemic use with testimonials of countless health benefits and is one of the most popular botanical medicines in the world for the management of a wide variety both of benign and serious ailments including irritable bowel syndromes, osteoarthritis, Type II diabetes mellitus, and viral respiratory illness. The human consumption of Aloe vera extract in beverage form has substantially grown over the last several decades, in no small part, due to the increased consumer interest in alternative approaches to health benefits. The principal aim of the present paper is to characterize the research to date that has explored the genotoxic potential of Aloe vera inner leaf gel extract and decolorized whole leaf extract used in commercially available food-grade drinkable products which contain no more than 10 ppm aloin. Despite prevailing public health opinion, especially in Europe, the consensus of the reviewed studies retrieved from the peer-reviewed literature together with a mutagenic evaluation of an Aloe vera whole leaf decolorized spray-dried powder is that these products are not genotoxic.

Temperature and pH Stability of Anthraquinones from Native Aloe vera Gel, Spray-Dried and Freeze-Dried Aloe vera Powders during Storage

The present study explored the stability of extracted anthraquinones (aloin, aloe-emodin and rhein) from whole-leaf Aloe vera gel (WLAG), its freeze-dried powder (FDP) and spray-dried powder (SDP) under varying pH and temperature conditions during storage. Each anthraquinone behaved differently under different processing parameters. The amount of anthraquinones present in the gel was higher than in FDP and SDP. The aloin contents decreased by more than 50% at 50 °C and 70 °C, while at 25 °C and 4 °C, the decrease was moderate. A substantial reduction in aloin concentration was noticed at pH 6.7, whereas it remained unaffected at pH 3.5. The temperature and pH had no significant effect on the stability of aloe-emodin. Interestingly, a small quantity of rhein was detected during storage due to the oxidative degradation of aloin into aloe-emodin and rhein. These findings can provide significant insight into retaining anthraquinones during processing while developing functional foods and nutraceuticals to obtain maximum health benefits.

The dark side of miracle plant-Aloe vera: a review

BACKGROUND

Aloe vera (Aloe barbadensis Miller), commonly known as Ghritkumari/Gwarpatha, is a member of the Liliaceae family, used in the traditional medicine system for ages. Aloe vera has made its importance as a therapeutic agent, acting as a cure for various diseases such as skin problems, lungs, and heart disorders, diabetes, ulcers, various microbial infections, and asthma. Despite its tremendous health benefits, the dark side of the plant is a reason of concern as there are several active compounds present in the plant, raising questions on its safe oral consumption and application.

METHODS AND RESULTS

The literature review was compiled from information resourced from various national and international journals available at Google Scholar and curated with Mendeley. The data mining was carried out during the period of January to May 2021. This study explored and summarized the dark side of Aloe vera, subjected to various secondary metabolites present in it. Aloin, the most active compound of Aloe vera, is a type of anthraquinone metabolized by human gut microflora, resulting in the formation of aloe-emodin anthraquinone, later being associated with several harmful effects such as carcinogenicity, genotoxicity, nephrotoxicity, and purgative. Besides this, several alkaloids and polysaccharides present in the plant are reported to cause hepatotoxicity and male infertility, respectively.

CONCLUSIONS

The harmful effects of the plants are not adequately discovered yet; hence there is a need to come up with some mechanism to understand and suppress the formation of such toxic compounds completely. This review examined the botany, active compounds, and adverse clinical effects in the range of metabolites associated with this herb - "Aloe vera".

The absence of genotoxicity of a mixture of aloin A and B and a commercial aloe gel beverage

Aloe products are increasingly valued as ingredients in food supplements and as flavoring agents. The global Aloe vera market is varied, large, growing, and increasingly important in food, cosmetics, and medicines. Aloin, an anthraquinone glycoside, is one of the major components by weight of the anthraquinone derivatives of Aloe vera gel. Principal metabolites, aloe emodin and emodin, are a source of debate concerning toxic vs salutary effects, hence the accurate toxicological characterization of these compounds has become increasingly important. The purpose of this study was to determine the genotoxic profile of a stabilized Aloe vera juice product derived from the inner filet and marketed as a beverage currently sold in the European Union containing 8 to 10 ppm aloin and a mixture of purified aloin A and B. The present data confirm that a commercial stabilized Aloe vera gel intended for consumption as a juice beverage is not genotoxic. Furthermore, both aloin A and B were negative in the same assays and therefore are also not genotoxic. These results are consistent with the work of other groups and contrast with data obtained using products containing the Aloe vera latex hydroxyanthracene derivatives (HADs).

The potential health benefits of aloin from genus Aloe

The Aloe species is known for its medicinal and cosmetic properties. Aloin is an active ingredient found in the leaves of medicinal plants of the genus Aloe. Aloin has attracted considerable interest for its antiinflammatory, anticancer, antibacterial, and antioxidant activities. However, since its clinical application is restricted by its unclear mechanism of action, a deeper understanding of its pharmacological activity is required. This review provides an overview of current pharmacological and toxicological studies published in English from February 2000 to August 2021. Herein, we summarized the sources and potential health benefits of aloin from a clinical application perspective to guide for further studies on the sources of aloin, aimed at efficiently increasing aloin production. Importantly, the function and mechanism of action of aloin remain unclarified. In future research, it is necessary to develop new approaches for studying the pharmacological molecular mechanisms underlying the activity of this compound against various diseases.

Network Pharmacology-Based Study on the Mechanism of Aloe Vera for Treating Cancer

BACKGROUND

Aloe vera has long been considered an anticancer herb in different parts of the world.

OBJECTIVE

To explore the potential mechanism of aloe vera in the treatment of cancer using network pharmacology and molecule docking approaches.

METHODS

The active ingredients and corresponding protein targets of aloe vera were identified from the TCMSP database. Targets related to cancer were obtained from GeneCards and OMIM databases. The anticancer targets of aloe vera were obtained by intersecting the drug targets with the disease targets, and the process was presented in the form of a Venn plot. These targets were uploaded to the String database for protein-protein interaction (PPI) analysis, and the result was visualized by Cytoscape software. Go and KEGG enrichment were used to analyze the biological process of the target proteins. Molecular docking was used to verify the relationship between the active ingredients of aloe vera and predicted targets.

RESULTS

By screening and analyzing, 8 active ingredients and 174 anticancer targets of aloe vera were obtained. The active ingredient-anticancer target network constructed by Cytoscape software indicated that quercetin, arachidonic acid, aloe-emodin, and beta-carotene, which have more than 4 gene targets, may play crucial roles. In the PPI network, AKT1, TP53, and VEGFA have the top 3 highest values. The anticancer targets of aloe vera were mainly involved in pathways in cancer, prostate cancer, bladder cancer, pancreatic cancer, and non-small-cell lung cancer and the TNF signaling pathway. The results of molecular docking suggested that the binding ability between TP53 and quercetin was the strongest.

CONCLUSION

This study revealed the active ingredients of aloe vera and the potential mechanism underlying its anticancer effect based on network pharmacology and provided ideas for further research.

Aloin induced apoptosis by enhancing autophagic flux through the PI3K/AKT axis in osteosarcoma

Background

Osteosarcoma is a malignant tumor of bone and soft tissue in adolescents. Due to its tumor biological behavior pattern, osteosarcoma usually generates poor prognosis. Autophagy is an important self-defense mechanism in osteosarcoma.

Methods

Cell viability in IC₅₀ testing and reverse assays was examined by the MTT assay. Cell apoptosis conditions were examined by flow cytometry, Hoechst 33,342 staining and apoptosis-related protein immunoblotting. Autophagy conditions were tested by autophagy-related protein immunoblotting, transmission electron microscopic observation and dual fluorescence autophagy flux detection. The possible targets of aloin were screened out by network pharmacology and bioinformatic methods. Osteosarcoma xenografts in nude BALB/c mice were the model for in vivo research on tumor suppression, autophagy induction, pathway signaling and toxicity tests. In vivo bioluminescence imaging systems, immunohistochemical assays, and gross tumor volume comparisons were applied as the main research methods in vivo.

Results

Aloin induced osteosarcoma apoptosis in a dose-dependent manner. Its possible effects on the PI3K/AKT pathway were screened out by network pharmacology methods. Aloin increased autophagic flux in osteosarcoma by downregulating the PI3K/AKT pathway. Aloin promoted autophagic flux in the osteosarcoma cell lines HOS and MG63 in a dose-dependent manner by promoting autophagosome formation. Chloroquine reversed the apoptosis-promoting and autophagy-enhancing effects of aloin. Autophagy induced by starvation and rapamycin significantly enhanced the autophagic flux and apoptosis induced by aloin, which verified the role of the PI3K/AKT axis in the pharmacological action of aloin. Therapeutic effects, autophagy enhancement and regulatory effects on the PI3K/AKT/mTOR pathway were demonstrated in a nude mouse xenogeneic osteosarcoma transplantation model.

Conclusions

Aloin inhibited the proliferation of osteosarcoma by inhibiting the PI3K/AKT/mTOR pathway, increasing autophagic flux and promoting the apoptosis of osteosarcoma cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-021-00520-4.

Review on the phytochemistry and toxicological profiles of Aloe vera and Aloe ferox

Background

Aloe vera and Aloe ferox have over the years been among the most sought-after Aloe species in the treatment of ailments worldwide. This review provides categorized literature on the phytochemical and scientifically proven toxicological profiles of A. vera and A. ferox to facilitate their exploitation in therapy.

Main body of the abstract

Original full-text research articles were searched in PubMed, ScienceDirect, Research gate, Google Scholar, and Wiley Online Library using specific phrases. Phenolic acids, flavonoids, tannins, and anthraquinones were the main phytochemical classes present in all the two Aloe species. Most of the phytochemical investigations and toxicity studies have been done on the leaves. Aloe vera and Aloe ferox contain unique phytoconstituents including anthraquinones, flavonoids, tannins, sterols, alkaloids, and volatile oils. Aloe vera hydroalcoholic leaf extract showed a toxic effect on Kabir chicks at the highest doses. The methanolic, aqueous, and supercritical carbon dioxide extracts of A. vera leaf gel were associated with no toxic effects. The aqueous leaf extract of A. ferox is well tolerated for short-term management of ailments but long-term administration may be associated with organ toxicity. Long-term administration of the preparations from A. vera leaves and roots was associated with toxic effects.

Short conclusion

This review provides beneficial information about the phytochemistry and toxicity of A. vera and A. ferox and their potential in the treatment of COVID-19 which up to date has no definite cure. Clinical trials need to be carried out to clearly understand the toxic effects of these species.

The toxicologic pathology aspects of selected natural herbal products and related compounds

Herbal products have been in use for many years, but they are becoming more and more popular in recent years, and they are currently in widespread use throughout the world. In this review article we describe the histopathologic findings found after exposure to 12 dietary herbals in studies conducted in rodent model systems. Clear or some evidence for carcinogenic activity was seen with 6 herbals, with the liver being the most common organ affected. The intestine was affected by two herbals (aloe vera nondecolorized extract and senna), three had no clear evidence for carcinogenic activity and one was cardiotoxic (Ephedrine and Ephedra in combination with caffeine). Information from these studies can help to better understand potential target organs for further evaluation from exposure to various herbal products.

Absence of genotoxicity of purified Aloe vera whole leaf dry juice as assessed by an in vitro mouse lymphoma tk assay and an in vivo comet assay in male F344 rats

Hydroxyanthracene derivatives (HAD) are naturally present in the latex layer of Aloe vera leaf, predominantly as aloins A, B and aloe-emodin. HAD are typically removed from commercial ingestible aloe products through activated charcoal filtration (decolorization). Current research aimed to evaluate genotoxic potential of a purified aloe whole leaf dry juice containing 0.3 ppm of total aloins and non-detectable aloe-emodin (LOD =0.01 ppm) in the L5178Y mouse lymphoma assay (MLA; OECD 490) and in vivo comet assay (OECD 489). No marked increases in mutant frequency at the tk locus were observed in the MLA at concentrations up to 5000 μg/mL for 3 h and 24 h (-S9), and up to a precipitating concentration of 3000 μg/mL for 3 h (+S9) compared to concurrent vehicle control. Relative total growth at the highest analyzable concentrations at 3 h (±S9) and 24 h (-S9) ranged from 64 to 133 %. In the comet assay, no statistically significant increases in DNA strand breaks were detected in the colon or kidney following oral gavage of 500, 1000 or 2000 mg/kg/day in male F344 rats for 2 days compared to concurrent vehicle control. Overall, these findings demonstrated the test article containing minimal HAD is not genotoxic under the described experimental conditions.

Modulation of gut microbiota in healthy rats after exposure to nutritional supplements

INTRODUCTION

Rats are experimental animals, frequently used as model organisms in the biomedical studies, and increasingly used to study the gut microbiota. Specifically, the aim of latter studies is either the elucidation of relationship between intestinal dysbiosis and diseases or the determination of nutrients or pharmaceutical agents which can cause the modulation in the presence or abundance of gut microbiota.

AIM

Herein, the research studies conducted on the gut microbiota of healthy rats are presented in a summarized and concise overview. The focus is on studies aimed to reveal the shifts in microbial composition and functional changes after exposure to various types of nutritional supplements.

METHODS

We performed the search of PubMed database using the term "rat gut microbiome microbiota" and examined studies aimed to assess the composition of gut microbiota in physiological homeostasis as well as the effect of various nutritional supplements on the gut microbiota of healthy rats.

Pharmacological Update Properties of Aloe Vera and its Major Active Constituents

Aloe vera has been traditionally used to treat skin injuries (burns, cuts, insect bites, and eczemas) and digestive problems because its anti-inflammatory, antimicrobial, and wound healing properties. Research on this medicinal plant has been aimed at validating traditional uses and deepening the mechanism of action, identifying the compounds responsible for these activities. The most investigated active compounds are aloe-emodin, aloin, aloesin, emodin, and acemannan. Likewise, new actions have been investigated for Aloe vera and its active compounds. This review provides an overview of current pharmacological studies (in vitro, in vivo, and clinical trials), written in English during the last six years (2014–2019). In particular, new pharmacological data research has shown that most studies refer to anti-cancer action, skin and digestive protective activity, and antimicrobial properties. Most recent works are in vitro and in vivo. Clinical trials have been conducted just with Aloe vera, but not with isolated compounds; therefore, it would be interesting to study the clinical effect of relevant metabolites in different human conditions and pathologies. The promising results of these studies in basic research encourage a greater number of clinical trials to test the clinical application of Aloe vera and its main compounds, particularly on bone protection, cancer, and diabetes.

Evaluation of anti-infective potencies of formulated aloin A ointment and aloin A isolated from Aloe barbadensis Miller

Introduction

Isolated bioactive components of plants or their raw extract are utilized as complementary or alternate remedy in copious illnesses. The current research was aimed at assessing the activity of aloin A isolated from Aloe barbadensis Miller and its formulated ointment against six (6) selected clinical isolates.

Methods

The column chromatography was utilized in isolating aloin A from chloroform/methanol solvent polarity. The characterization of the isolated compound was performed by spectroscopy techniques corresponding to UV, IR, ¹H- and ¹³C-NMR spectroscopy. It was formulated as ointment using polyethylene glycol (PEG) and both the ointment and the isolated compound were probed for in vitro antimicrobial activity.

Results

Aloin A has been isolated from chloroform/methanol solvent mixture. The structure has been explicated as (10S)-10-β-d-glucopyranosyl-1,8-dihydroxy-3-(hydroxymethyl)-9(10H)-anthracenone(1S)-1,5-anhydro-1-[(9S)-4,5-dihydroxy-2-(hydroxymethyl)-10-oxo-9,10-dihydro-9-anthracenyl]-d-glucitol. The minimum inhibitory concentration (MIC) of the isolated aloin A on the pathogens ranged from 2.5 to 5.0 mg/ml and 0.32 to 5.0 mg/ml for both aloin A and the formulated ointment respectively. It was further revealed that the activity of aloin A showed dose dependence against all the test microorganisms. There was no significant difference in the activity of the drug against K. pneumoniae, S. aureus, E. coli, C. albicans and T. flavus (P > 0.05) when the concentration was raised from 2.5 to 5 mg/ml, however, there was significant difference (P ˂ 0.05) in activity against P. aeruginosa. The formulated ointment exhibited dose dependent activity against all test microorganisms. At low concentrations, the ointment showed no significant difference in diameter zone of inhibition against all test microorganisms (P > 0.05) except P. aeruginosa which exhibited a highly significant difference (P < 0.05).

Conclusion

Both the isolated aloin A and its formulated ointment demonstrated substantial inhibition of growth of the pathogenic strains. These findings sturdily suggest that aloin A is a nascent drug that could be explored as skin and wound transmittable agent.

Undervalued potential of crassulacean acid metabolism for current and future agricultural production

The potential for crassulacean acid metabolism (CAM) to support resilient crops that meet demands for food, fiber, fuel, and pharmaceutical products far exceeds current production levels. This review provides background on five families of plants that express CAM, including examples of many species within these families that have potential agricultural uses. We summarize traditional uses, current developments, management practices, environmental tolerance ranges, and economic values of CAM species with potential commercial applications. The primary benefit of CAM in agriculture is high water use efficiency that allows for reliable crop yields even in drought conditions. Agave species, for example, grow in arid conditions and have been exploited for agricultural products in North and South America for centuries. Yet, there has been very little investment in agricultural improvement for most useful Agave varieties. Other CAM species that are already traded globally include Ananas comosus (pineapple), Aloe spp., Vanilla spp., and Opuntia spp., but there are far more with agronomic uses that are less well known and not yet developed commercially. Recent advances in technology and genomic resources provide tools to understand and realize the tremendous potential for using CAM crops to produce climate-resilient agricultural commodities in the future.

Study of the aqueous extract of Aloe vera and its two active components on the Wnt/β-catenin and Notch signaling pathways in colorectal cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Aloe vera (L.) Burm. f. (Aloe vera) is a common Traditional Chinese Medicine (TCM) recorded in Pharmacopoeia of the People's Republic of China (version 2015). It has been traditionally used for treatment of constipation. Aloe vera requires much attention for its safety evaluation because several studies have reported the association between oral consumption of Aloe vera and the development of colorectal cancer (CRC). However the material basis and molecular mechanism are.still less well elucidated. Although Wnt/β-catenin and Notch signaling pathway have been known to be closely related to the initiation and development of CRC, the impacts of Aloe vera on these cancerous pathways have not been completely determined yet.

AIM OF THIS STUDY

Hence, this study aimed to study the impacts of Aloe vera on the Wnt/β-catenin and Notch signaling pathway, as well as proliferation of CRC cells.

MATERIALS AND METHODS

Firstly, the effects of Aloe vera aqueous extract and its two active components (aloin and aloesin) on the Wnt/β-catenin and Notch signaling pathway were studied by luciferase reporter, RT-qPCR, western blotting and immunofluorescence assays, respectively. Furthermore, RNA sequencing analysis (RNA-seq) was then performed to verify their regulatory activities on the Wnt-related and Notch-related genes expression. Finally, their impacts on RKO cell proliferation and cell cycle phase were also evaluated via MTT assay and cell cycle analysis.

RESULTS

Our results indicate that the aqueous extract of Aloe vera and its active component aloin activated the Wnt/β-catenin pathway and inhibited the Notch signaling pathway only in the presence of Wnt3a. While aloesin was characterized to directly activate the Wnt/β-catenin pathway and inhibit the Notch pathway independent of Wnt3a. Within 24h, the Aloe vera extract and its two components were failed to affect the proliferation or cell cycle phase of RKO cells. Nevertheless, in the presence of Wnt3a, the aqueous extract of Aloe vera with the concentration of 33.3 μg/ml start to promote the cell proliferation of RKO cells after 48h incubation.

CONCLUSION

In conclusion, this study showed that Aloe vera extract and its active component aloin activated the Wnt/β-catenin pathway and inhibited the Notch pathway in the presence of Wnt3a. While another active component, aloesin, activated the Wnt/β-catenin pathway and inhibited the Notch signaling pathway independent of Wnt3a. Given that Wnt/β-catenin and Notch pathway are closely associated with the progression of CRC, these findings would be helpful to better understand the colonic carcinogenicity of Aloe vera.

UHPLC-MS/MS method for the quantification of aloin-A in rat plasma and its application to a pharmacokinetic study

Aloin-A (also known as barbaloin), the main bioactive anthraquinone-C-glycoside of Aloe species, exhibits various beneficial pharmacological effects. However, the determination and pharmacokinetic study of aloin-A in rat plasma need to be improved and systematically demonstrated. In the present study, a simple, robust and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for rapid quantification of aloin-A in rat plasma was developed. Plasma preparation was conducted by a single step protein precipitation with obtusin serving as an internal standards (IS) followed by separation of the analytes using an Agilent C18 column with a gradient mobile phase comprised of acetonitrile and formic acid aqueous solution. Negative ion electrospray was used and multiple reaction monitoring transitions were m/z 417.1 → 297.0 for aloin-A and m/z 343.1 → 328.1 for IS, respectively. The developed method was validated with linear range of 1-1000 ng/mL. All validation parameters were well within the acceptance criteria based on the guidance of FDA. The validated approach was successfully applied to analyze samples from a pharmacokinetic study in healthy rats following intravenous and oral administration. Aloin-A was found to be quickly absorbed, extensively distributed and rapidly eliminated. The absolute bioavailability of aloin-A was 5.79%.

Gut microbiota in phytopharmacology: A comprehensive overview of concepts, reciprocal interactions, biotransformations and mode of actions

The dynamic and delicate interactions amongst intestinal microbiota, metabolome and metabolism dictates human health and disease. In recent years, our understanding of gut microbial regulation of intestinal immunometabolic and redox homeostasis have evolved mainly out of in vivo studies associated with high-fat feeding induced metabolic diseases. Techniques utilizing fecal transplantation and germ-free mice have been instrumental in reproducibly demonstrating how the gut microbiota affects disease pathogenesis. However, the pillars of modern drug discovery i.e. evidence-based pharmacological studies critically lack focus on intestinal microflora. This is primarily due to targeted in vitro molecular-approaches at cellular-level that largely overlook the etiology of disease pathogenesis from the physiological perspective. Thus, this review aims to provide a comprehensive understanding of the key notions of intestinal microbiota and dysbiosis, and highlight the microbiota-phytochemical bidirectional interactions that affects bioavailability and bioactivity of parent phytochemicals and their metabolites. Potentially by focusing on the three major aspects of gut microbiota i.e. microbial abundance, diversity, and functions, I will discuss phytochemical-microbiota reciprocal interactions, biotransformation of phytochemicals and plant-derived drugs, and pre-clinical and clinical efficacies of herbal medicine on dysbiosis. Additionally, in relation to phytochemical pharmacology, I will briefly discuss the role of dietary-patterns associated with changes in microbial profiles and review pharmacological study models considering possible microbial effects. This review therefore, emphasize on the timely and critically needed evidence-based phytochemical studies focusing on gut microbiota and will provide newer insights for future pre-clinical and clinical phytopharmacological interventions.

Dose-Dependent Effects of Aloin on the Intestinal Bacterial Community Structure, Short Chain Fatty Acids Metabolism and Intestinal Epithelial Cell Permeability

Aloe leaf or purified aloin products possess numerous therapeutic and pharmaceutical properties. It is widely used as ingredients in a variety of food, cosmetic and pharmaceutical products. Animal studies have shown that consumption of aloe or purified aloin cause intestinal goblet cell hyperplasia, and malignancy. Here, we tested antibacterial effects of aloin, against intestinal commensal microbiota. Minimum inhibitory concentration of aloin for several human commensal bacterial species (Gram-positive and Gram-negative) ranged from 1 to 4 mg/ml. Metabolism studies indicated that Enterococcus faecium was capable of degrading aloin into aloe-emodin at a slower-rate compared to Eubacterium spp. As a proof of concept, we incubated 3% rat fecal-slurry (an in vitro model to simulate human colon content) with 0.5, 1, and 2 mg/ml of aloin to test antimicrobial properties. Low aloin concentrations showed minor perturbations to intestinal bacteria, whereas high concentration increased Lactobacillus sp. counts. Aloin also decreased butyrate-production in fecal microbiota in a dose-dependent manner after 24 h exposure. The 16S rRNA sequence-data revealed that aloin decreases the abundance of butyrate-producing bacterial species. Transepithelial resistant result revealed that aloin alters the intestinal barrier-function at higher concentrations (500 μM). In conclusion, aloin exhibits antibacterial property for certain commensal bacteria and decreases butyrate-production in a dose -dependent manner.

HIGHLIGHTS

    –Aloin exhibits antibacterial properties for certain intestinal commensal bacteria.

    –In rat fecal slurry (an in vitro model to simulate human colon content), longer aloin exposure (24 h) decreases the butyrate production in dose dependent manner.

    –The 16s rRNA sequencing data show that aloin decreased the abundance of butyrate producing bacterial species.

    –Rat intestinal commensal bacteria metabolized aloin into aloe-emodin.

    –Aloin altered the intestinal epithelial cells barrier integrity, however, the metabolic product of aloin - Aloe-emodin did not alter epithelial cells permeability.

Finding the bad actor: Challenges in identifying toxic constituents in botanical dietary supplements

Botanical-derived dietary supplements have widespread use in the general population. The complex and variable nature of botanical ingredients and reports of adverse responses have led to concern for negative human health impacts following consumption of these products. Toxicity testing of the vast number of available products, formulations, and combinations is not feasible due to the time and resource intensive nature of comprehensive testing. Methods are needed to assess the safety of a large number of products via more efficient frameworks. Identification of toxicologically-active constituents is one approach being used, with many advantages toward product regulation. Bioassay-guided fractionation (BGF) is the leading approach used to identify biologically-active constituents. Most BGF studies with botanicals focus on identifying pharmacologically-active constituents for drug discovery or botanical efficacy research. Here, we explore BGF in a toxicological context, drawing from both efficacy and poisonous plant research. Limitations of BGF, including loss of mixture activity and bias toward abundant constituents, and recent advancements in the field (e.g., biochemometrics) are discussed from a toxicological perspective. Identification of active constituents will allow better monitoring of market products for known toxicologically-active constituents, as well as surveying human exposure, two important steps to ensuring the safety of botanical dietary supplements.