Safety evaluation of supercritical carbon dioxide extract of Aloe vera gel

Aloe vera-An Extensive Review Focused on Recent Studies

Since ancient times, Aloe vera L. (AV) has attracted scientific interest because of its multiple cosmetic and medicinal properties, attributable to compounds present in leaves and other parts of the plant. The collected literature data show that AV and its products have a beneficial influence on human health, both by topical and oral use, as juice or an extract. Several scientific studies demonstrated the numerous biological activities of AV, including, for instance, antiviral, antimicrobial, antitumor, and antifungal. Moreover, its important antidepressant activity in relation to several diseases, including skin disorders (psoriasis, acne, and so on) and prediabetes, is a growing field of research. This comprehensive review intends to present the most significant and recent studies regarding the plethora of AV's biological activities and an in-depth analysis exploring the component/s responsible for them. Moreover, its morphology and chemical composition are described, along with some studies regarding the single components of AV available in commerce. Finally, valorization studies and a discussion about the metabolism and toxicological aspects of this "Wonder Plant" are reported.

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.

Validation of an LC-MS/MS method for the quantitation of phytosterols derived from Aloe vera gel

A method to quantitate five minor phytosterols named Aloe sterols identified from Aloe vera gel was validated using AVGP (Aloe vera gel powder) as the sample. To measure the Aloe sterols content, AVGP was extracted with chloroform/methanol (2:1, v/v) and analyzed by liquid chromatography-tandem mass spectrometry. The calibration curve revealed a high coefficient of determination (>0.999). The limit of quantification was 2.3–4.1 ng/mL. Average recoveries ranged from 95 to 105%. The intra-day and inter-day precision were 2.6–6.4% and 3.8–7.3%, respectively, confirming good method precision. Aloe sterols were also quantified in AVGE (Aloe vera gel extract) using this method. We showed that the composition ratio of each Aloe sterol in AVGP did not change in AVGE. Additionally, we measured the concentration of Aloe sterols in the capsule containing AVGE, and confirmed that it was stable even after 1 year of storage.

In conclusion, a quantification method was established to simultaneously measure multiple plant sterols with similar structures.

• A quantification method to simultaneously measure several plant sterols with similar structures was established.

• Results from the intra-day precision and the inter-day precision confirmed good precision.

• This method can be applied to processed raw materials and/or foods in long-term storage.

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).

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.

Pharmacological reflection of plants traditionally used to manage diabetes mellitus in Tanzania

ETHNOPHARMACOLOGICAL RELEVANCE

The increasing national prevalence of diabetes mellitus (DM) and its complications have overstretched the health care system in Tanzania and influenced patients to use herbal medicines as alternative therapeutic strategies. Therefore, an urgent need exists to validate the safety and efficacy of plants used locally.

AIM OF THE STUDY

To identify plants used for the management of DM in Tanzania and analyses their pharmacological, phytochemistry, and safety evidence with a special focus on the mechanism of action.

METHODS

Researchers searched Medline, web of science, and Scopus for published articles. Also, specialized herbarium documents of Muhimbili Institute of traditional medicine were reviewed. Articles were assessed for relevance, quality, and taxonomical accuracy before being critically reviewed.

RESULTS

We identified 62 plant species used locally for DM management. Moringa oleifera Lam. and Cymbopogon citratus (D.C) stapf were the most mentioned. Fifty-four phytochemicals from 13 species had DM activities. These were mainly; polyphenolics, phytosterols, and triterpenoids. Extracts, fractions, and pure compounds from 18 species had in vitro antidiabetic activities of which 14 had α-glucosidase and α-amylase inhibition effects. The most studied -Momordica charantia L. increased; glucose uptake and adiponectin release in 3T3-L1 adipocytes, insulin secretion, insulin receptor substrate-1 (IRS-1), GLUT-4 translocation, and GLP-1 secretion; and inhibited protein tyrosine phosphatase 1 B (PTP1B). Preclinical studies reported 30 species that lower plasma glucose with molecular targets in the liver, skeletal muscles, adipose tissues, pancreases, and stomach. While three species; Aspilia mossambiscensis (Oliv.) Willd, Caesalpinia bonduc (L.) Roxb, and Phyllanthus amarus Schumach. & Thonn. had mild toxicity in animals, 33 had no report of their efficacy in DM management or toxicity.

CONCLUSION

Local communities in Tanzania use herbal medicine for the management of DM. However, only a fraction of such species has scientific evidence. A. mossambiscensis, C. bonduc., and P. amarus had mild toxicity in animals. Together, our findings call for future researches to focus on in vitro, in vivo, and phytochemical investigation of plant species for which their use in DM among the local communities in Tanzania have not been validated.

Safety evaluation of Aloe vera soft capsule in acute, subacute toxicity and genotoxicity study

Aloe vera has been widely used in health and nutritional supplements in Chinese herbal medicine. Furthermore, Aloe vera production has been an emerging industry for making cosmetics and functional food. However, the reported adverse effects raised questions as to whether Aloe vera and its products were safe enough to be used in medicine and health care. In view of this, the safety evaluation of Aloe vera products before marketing is very important. The present study aimed to assess the toxicological profile of Aloe vera soft capsule (ASC), through acute, subacute toxicity and genotoxicity tests. Male and female ICR mice were received by oral gavage 15000 mg/kg bodyweight of ASC in the acute toxicity test. Male and female SD rats were fed on diet blended with different doses of ASC (equivalent to 832.5, 1665 and 3330 mg/kg bodyweight of ASC) for the subacute toxicity test. In the acute toxicity study, no mortality or behavioral changes were observed, indicating the LD50 was higher than 15000 mg/kg bodyweight. In the subacute toxicity test, no significant changes were observed in bodyweight, food consumption, hematological, biochemical or histopathological parameters in the rats exposed. These data suggested that ASC used in this study did not produce any marked subacute toxic effects up to a maximum concentration of 3330 mg/kg bodyweight. In the genotoxicity study, ASC showed no mutagenic activity in the Ames test and no evidence of potential to induce bone marrow micronucleus or testicular chromosome aberrations in ICR mice exposed to 10000 mg/kg bodyweight. Collectively, ASC could be considered safe before it was marketed as a laxative and moistening health food.

Effects of low-dose Aloe sterol supplementation on skin moisture, collagen score and objective or subjective symptoms: 12-week, double-blind, randomized controlled trial

Daily oral intake of 40 μg Aloe sterol was shown in a double‐blind clinical trial to significantly increase skin barrier function, moisture and elasticity. Ultrasonographic results also suggested that the intake of Aloe sterol increases collagen content in the dermis. Here, we evaluate the effects of a much smaller dose of Aloe sterol, approximately half that used previously, on skin functions in more detail. This is a monocentric, double‐blind, randomized, placebo‐controlled, supplementation study of the effects of low‐dose Aloe sterol on skin transepidermal water loss, hydration, collagen score, evaluation of objective or subjective symptoms, and safety after 12 weeks of daily intake. We randomly administrated either Aloe sterol or placebo to 122 healthy volunteers. Transepidermal water loss was significantly reduced and collagen score was increased in the Aloe sterol group compared with the placebo group at week 12. In the Aloe sterol group, there was significant improvement of objective skin condition (face erythema and pruritus of inner and outer arms) at week 12 compared with week 0, but not in the placebo group. Subjectively, there was significant improvement of visual analog scale of skin acne, fingernail brittleness and constipation in the Aloe sterol group. According to subgroup analysis, although not planned before the study initiation, subjects with dry skin in the Aloe sterol group had significantly increased skin hydration values at week 12 compared with the placebo group. Our results confirmed that even low‐dose Aloe sterol ingestion improves skin moisture by promoting skin barrier function and dermal collagen production, which contributes to maintenance of healthy skin.

Aloe veraat the frontier of glycobiology and integrative medicine: Health implications of an ancient plant

Aloe vera plant extracts are ubiquitous in foods, cosmetics, and medicine. Like all plants, these extracts contain an array of potential bioactives or glycans, which may contribute to health when applied or consumed. In the Aloe vera plant, these bioactives are dominated by acemannan, a type of carbohydrate, and related complexes of saccharides, proteins, and lipids. Clinical data suggest aloe extracts may be beneficial in the management of cutaneous and some systemic conditions, such as some forms of immune dysfunction, atherogenesis, malignancy, and numerous cell functions. These extracts also contain an entourage of bioactive substances that may be allergenic and potentially toxic as well as salutary. These substances include aloin and a variety of anthracenes. The concentrations of potential allergens, aloin, and related compounds are markedly reduced through controlled decolorization processes that are utilized by leading Aloe products manufacturers. The entourage effects of contemporary Aloe vera when consumed or applied topically represent opportunities for clinical investigation which may be applied to commercial consumer products and therapeutic indications. Future research should fully explore the range of bioactive glycan components and their respective safety and efficacy. The history and ongoing popularity of Aloe vera products represent a pragmatic mandate for well-designed investigation into the diverse functional roles of glycans.

Lead bioactive compounds of Aloe vera as potential anticancer agent

Aloe vera (Aloe barbadensis Miller) is a perennial succulent medicinal plant. It has been used as a traditional or folk medicine for thousands of years and claimed that it possesses wound and burn healing activities, and anti-inflammatory as well as immunomodulatory effects. In recent years, the use of Aloe vera has been growing as a dietary supplement. The pre-clinical studies over the last couple of decades uncover the potential therapeutic activities of Aloe vera and its bioactive compounds, especially against neoplastic disease. Such investigations indicate the possible preventive as well as therapeutic effects of Aloe vera against cancer. Here, we discuss the crucial bioactive compounds of Aloe vera that have been harnessed against cancer and also address several mechanisms of action of these lead bioactive compounds compared to other standard drugs involved in cancer prevention and treatment.

Protective effects of Aloe sterols against UVB-induced photoaging in hairless mice

BACKGROUND

Aloe vera is a traditional medical plant whose gel has been widely used in skin care. Previously, we have identified Aloe sterols from Aloe vera as active ingredients. This study investigated the protective effects of Aloe sterols without polysaccharides, against ultraviolet B (UVB)-induced skin photoaging in mice using Aloe vera gel extract (AVGE) obtained by supercritical fluid extraction.

METHODS

Aloe vera gel extract was supplemented in the diet (12 or 120 ppm), and HR-1 hairless mice were exposed to UVB irradiation for 7 weeks. Skin measurements and histological and analytical studies were performed.

RESULTS

Repeated UVB irradiation induced rough wrinkling of skin with water content reduction and hyperkeratosis. AVGE administration resulted in the significant improvement of UVB-induced skin dryness, epidermal thickness, and wrinkle formation. The AVGE group also suppressed the degenerations of dermal collagen fibers and the appearance of cutaneous apoptosis cells induced by UVB. Furthermore, AVGE administration reduced the excess elevation of pro-inflammatory cytokines (IL-1β and TNF-α) and matrix metalloproteinases (MMP-2, MMP-9, MMP-12, and MMP-13) in UVB-exposed skin.

CONCLUSION

The dietary ingestion of Aloe sterols protected against chronic UVB damage in mouse skin, and our results suggest that Aloe sterols may prevent skin photoaging through the anti-inflammation and MMP regulation.

Aloe vera: A review of toxicity and adverse clinical effects

The Aloe plant is employed as a dietary supplement in a variety of foods and as an ingredient in cosmetic products. The widespread human exposure and its potential toxic and carcinogenic activities raise safety concerns. Chemical analysis reveals that the Aloe plant contains various polysaccharides and phenolic chemicals, notably anthraquinones. Ingestion of Aloe preparations is associated with diarrhea, hypokalemia, pseudomelanosis coli, kidney failure, as well as phototoxicity and hypersensitive reactions. Recently, Aloe vera whole leaf extract showed clear evidence of carcinogenic activity in rats, and was classified by the International Agency for Research on Cancer as a possible human carcinogen (Group 2B). This review presents updated information on the toxicological effects, including the cytotoxicity, genotoxicity, carcinogenicity, and adverse clinical effects of Aloe vera whole leaf extract, gel, and latex.

Content of toxic and essential metals in recrystallized and washed table salt in Shiraz, Iran

BACKGROUND

Table salt is the most commonly used food additive. Since most of the salt consumed in Iran comes from mines, contamination with heavy metals is a health concern. The commonest salt purification method in Iran is washing with water. But recently, some industries have turned to recrystallization method. The present study aimed to determine the level of essential and non-essential heavy metals in the table salt refined with recrystallization and washing methods.

METHODS

Thirty eight pre-packed salt samples were directly collected from retail market in Shiraz (22 samples refined with recrystallization method and 16 with washing method). The level of lead, cadmium, copper, zinc, nickel and cobalt was determined using Voltammetric method. Daily intakes of lead and cadmium as well as their weekly intakes were calculated.

RESULTS

The levels of lead, cadmium, copper, zinc, nickel and cobalt in recrystallized samples were 0. 30 ± 0.26, 0.02 ± 0.02, 0.11 ± 0.06, 0.34 ± 0.22, 0.15 ± 0.19 and 0.008 ± 0.007 μg/g, respectively, and also 0.37 ± 0.27, 0.017 ± 0.021, 0.19 ± 0.18, 0.37 ± 0.20, 0.13 ± 0.23 and 0.037 ± 0.06 μg/g in washed salt samples. The calculated weekly intake of lead and cadmium was 0.216 and 0.014 μg/kg, respectively for the recrystallized and 0.2653 and 0.0119 μg/kg for the washed salts.

CONCLUSION

All values for toxic metals were lower than the permitted maximum for human consumption as prescribed by Codex and Institute of Standards and Industrial Research of Iran. Only 0.8652-1.0612% of lead and 0.17-0.2% of cadmium PTWIs are received via salt consumption weekly.

The no-observed-adverse-effect level (NOAEL) of baby aloe powder (BAP) for nutraceutical application based upon toxicological evaluation

Aloe has been used in versatile herbal medications and nutraceuticals throughout history. Aloe is widely considered to be generally safe for humans and used globally. The effectiveness and pharmacological properties of aloe are dependent upon when the plant is collected. However, little is known about the toxicology of whole-body aloe collected within less than 1 yr. Based upon widespread exposure to aloe, it is important to determine a daily intake level of this chemical to ensure its safety for humans. To determine the no-observed-adverse-effect level (NOAEL) of baby aloe powder (BAP) for clinical application, Sprague-Dawley (SD) rats were treated orally for 4 wk with 4 different concentrations: 0, 0.125, 0.5, and 2 g/kg body weight (bw). In this study, no significant or dose-dependent toxicological effects of BAP were observed in biochemical or hematological parameters, urinalysis, clinical signs, body weight, and food and water consumption. There were changes in some biomarkers in certain treated groups compared to controls; however, all values were within their reference ranges and not dose-dependent. Based on these results, the NOAEL of BAP was estimated to be greater than 2 g/kg bw in male and 2 g/kg bw in female SD rats. Collectively, these data suggest that BAP used in this study did not produce any marked subacute toxic effects up to a maximum concentration of 2 g/kg bw, and thus use in nutraceuticals and in pharmaceutical and cosmetic applications at a concentration of >2 g/kg is warranted.

Safety of purified decolorized (low anthraquinone) whole leaf Aloe vera (L) Burm. f. juice in a 3-month drinking water toxicity study in F344 rats

Decolorized (purified, low anthraquinone) whole leaf Aloe vera (L.) Burm. f. juice was administered at concentrations of 0%, 0.5%, 1% and 2% in the drinking water of F344Du rats for 3 months without any adverse effect. The no-observed-adverse-effect level (NOAEL) in this study was considered to be >2%w/v (>1845 mg/kg bodyweight/day for males and >2920 mg/kg bodyweight for females). The test material contained total anthraquinones at <0.1 parts per million. In the present study there was a complete absence of any histological alteration in samples from the cecum, colon (proximal, mid and distal regions). Similar concentrations of non-decolorized (unpurified, high anthraquinone) Aloe vera extracts tested in other studies have resulted in an increased incidence and severity of diarrhea and colon adenomas and carcinomas. The results of this study supports the assertion that the high levels of anthraquinone present in orally administered, non-purified whole leaf Aloe vera extract may be responsible for the adverse effects observed on the colon.

Toxicologic assessment of a commercial decolorized whole leaf aloe vera juice, lily of the desert filtered whole leaf juice with aloesorb

Aloe vera, a common ingredient in cosmetics, is increasingly being consumed as a beverage supplement. Although consumer interest in aloe likely stems from its association with several health benefits, a concern has also been raised by a National Toxicology Program Report that a nondecolorized whole leaf aloe vera extract taken internally by rats was associated with intestinal mucosal hyperplasia and ultimately malignancy. We tested a decolorized whole leaf (DCWL) aloe vera, treated with activated charcoal to remove the latex portion of the plant, for genotoxicity in bacteria, acute/subacute toxicity in B6C3F1 mice, and subchronic toxicity in F344 rats. We found this DCWL aloe vera juice to be nongenotoxic in histidine reversion and DNA repair assays. Following acute administration, mice exhibited no adverse signs at 3- or 14-day evaluation periods. When fed to male and female F344 rats over 13 weeks, DCWL aloe led to no toxicity as assessed by behavior, stools, weight gain, feed consumption, organ weights, and hematologic or clinical chemistry profiles. These rats had intestinal mucosal morphologies—examined grossly and microscopically—that were similar to controls. Our studies show that oral administration of this DCWL aloe juice has a different toxicology profile than that of the untreated aloe juice at exposures up to 13 weeks.

An in vitro and in vivo toxicologic evaluation of a stabilized aloe vera gel supplement drink in mice

Aloe vera gel is increasingly consumed as a beverage dietary supplement. The purpose of this study was to determine potential toxicity of a stabilized aloe vera gel derived from the inner gel fillet and marketed as a drink. The gel juice was assessed through assays of genotoxicity in vivo and acute and subchronic toxicity in B6C3F1 mice. Aloe vera did not increase the SOS DNA repair response in Escherichia coli and at 1× and 0.25× it did not increase mutagenesis of Salmonella TA100 resulting in histidine biosynthesis. At 3 and 14days following acute exposure, male and female mice gavaged with the stabilized aloe gel had daily appearances, total body weight gain, selected organ weights, necropsy and hematology tests similar to control mice gavaged with water. After a 13-week aloe gel feed study, male and female mice evaluated by the same criteria as the acute study plus feed consumption and serum chemistry tests were found to be equivalent to control groups. These data indicate that a commercial stabilized aloe gel consumed as a beverage was not genotoxic or toxic in vivo. These results contrast with those obtained using preparations containing aloe latex phenolic compounds such as anthraquinones.