Physician Beware: Severe Cyanide Toxicity from Amygdalin Tablets Ingestion

'Vitamin B17': Killing more than cancer

OBJECTIVE

Vitamin B17 tablets are sold (online) as an alternative cancer therapy medication. Its use however is not benign, given that it is metabolised into hydrogen cyanide. We aimed to measure the number of calls received by the New South Wales Poisons Information Centre (NSW PIC) regarding Amygdalin exposures.

METHODS

A retrospective review of all amygdalin/cyanogenic glycoside product ingestion exposure calls to NSW PIC between 2015 and 2022.

RESULTS

There were 120 unique exposure calls. Eighty-two (68%) were regarding minor exposures, with the remaining 38 (32%) of calls involving patients who had either a signifcant history or symptoms to prompt referral to hospital or were already seeking advice from a treating hospital clinican.

CONCLUSION

There is a significant burden of concern generated from the misuse of cyanogenic glycoside products for cancer prevention and treatment, which can result in hospital admission carrying significant health risk and expenditure.

Establishment of a Sonotrode Ultrasound-Assisted Extraction of Phenolic Compounds from Apple Pomace

Apple pomace is the main by-product from apple processing in the juice industry and is considered a source of polyphenols with several health bioactivities. Thus, this research focuses on the establishment of the ultrasound-assisted extraction of total phenolic compounds, focusing on phloretin and phloridzin, with high antioxidant activity from apple pomace, using a sonotrode. We used a Box-Behnken design of 15 experiments with 3 independent factors (ethanol (%), time (min) and amplitude (%)). The responses evaluated were the sum of phenolic compounds, phloretin and phloridzin measured by HPLC-MS-ESI-TOF, and antioxidant activity measured by DPPH, ABTS and FRAP. The validity of the model was confirmed by ANOVA. Further, it was carried out using a comparison between different apple pomaces with or without seeds extracted by the optimal conditions. Phloretin and phloridzin accounted for 7 to 32% of the total phenolic compounds in the apple pomaces. Among all the apple pomace analyzed, that of the variety Gala had the highest phenolic content and antioxidant activity. The presence of the cyanogenic compound amygdalin was detected in apple pomaces that contained seeds accompanied with a higher content of phloretin and phloridzin but a lower content of flavan-3-ols.

In Vitro and In Vivo Evaluation of the Effectiveness and Safety of Amygdalin as a Cancer Therapy

Cancer is one of the most important causes of death worldwide. Several studies have shown the efficacy of apricot kernel seed as a cancer therapy due to the presence of amygdalin. These studies have demonstrated amygdalin's cytotoxicity, antioxidant activity, and apoptosis in vitro using human cancer cell lines. However, no studies have demonstrated their cancer activity in vivo. The aim of this study is to develop an amygdalin-loaded niosomes (ALN) gel formulation as a drug delivery system in order to investigate the selectivity, efficacy, and toxicity of amygdalin as a cancer therapy in vivo using the 7,12-dimethylbenz (a) anthracene (DMBA) carcinoma rat model. Based on pre-formulation studies, the ALN formulation composed of Tween 60: cholesterol: dihexadecyl phosphate in a molar ratio of 1:2:0.1 was chosen as an optimum formulation because it has a percent of EE of 66.52% with a particle size of 269.3 nm and a reflux of 3.54 µg.cm^-2.h^-1. The ALN gel formulation was integrated into carbopol gel to be evaluated in vivo. Compared to DMBA control, treatment with ALN gel showed a reduction in the carcinoma volume and in the hyperplasia of the epidermis with no signs of edema. In conclusion, the ALN gel formulation could be an efficient cancer therapy.

Effect on Osteoclast Differentiation and ER Stress Downregulation by Amygdalin and RANKL Binding Interaction

Bone diseases such as osteoporosis are the result of osteoclast over-activation. There are many therapeutic agents from natural compounds inhibiting the formation of osteoclast that have been reported and are continuously being interested. Amygdalin (AD) is isolated from seeds of Prunus armeniaca L. which has many pharmaceutical effects; however, the effect of AD on osteoclast formation and function remains unknown. Therefore, the underlying mechanism of AD on RANKL-induced osteoclast in RAW 264.7 cells was investigated. Molecular docking simulation revealed that AD can bind to the active sites of RANKL with negative binding affinities. Through TRAP activity, bone resorption, and migration, AD effectively inhibited osteoclast differentiation and function. Expression of transcription factors, such as NFATc1, c-fos, and osteospecific genes (including dcstamp, acp5, ATP6v0d2, and ctsk results) showed an osteoclast differentiated inhibitory effect by AD treatment. In addition, RANKL-induced activation of MAPK, ER stress, and ROS levels in RANKL-induced osteoclast was significantly inhibited while antioxidant enzymes were recovered in the presence of AD. These results suggest that AD may be a potential candidate derived from natural sources for the treatment of osteoclast bone-related diseases.

Inflammation, It's Regulation and Antiphlogistic Effect of the Cyanogenic Glycoside Amygdalin

The inflammatory reaction accompanies in part or in full any disease process in the vascularized metazoan. This complicated reaction is controlled by regulatory mechanisms, some of which produce unpleasant symptomatic manifestations of inflammation. Therefore, there has been an effort to develop selective drugs aimed at removing pain, fever, or swelling. Gradually, however, serious adverse side effects of such inhibitors became apparent. Scientific research has therefore continued to explore new possibilities, including naturally available substances. Amygdalin is a cyanogenic glycoside present, e.g., in bitter almonds. This glycoside has already sparked many discussions among scientists, especially about its anticancer potential and related toxic cyanides. However, toxicity at different doses made it generally unacceptable. Although amygdalin given at the correct oral dose may not lead to poisoning, it has not yet been accurately quantified, as its action is often affected by different intestinal microbial consortia. Its pharmacological activities have been studied, but its effects on the body's inflammatory response are lacking. This review discusses the chemical structure, toxicity, and current knowledge of the molecular mechanism of amygdalin activity on immune functions, including the anti-inflammatory effect, but also discusses inflammation as such, its mediators with diverse functions, which are usually targeted by drugs.

The Multiple Actions of Amygdalin on Cellular Processes with an Emphasis on Female Reproduction

The present review summarizes the current knowledge on the provenance and properties, metabolism and toxicity, mechanism of action, physiological, and therapeutic roles of amygdalin-a molecule present in the seeds of apricot and other plants-with an emphasis on the action of amygdalin on reproductive processes, particularly in the female. Amygdalin influences physiological processes including female reproduction at various regulatory levels via extra- and intracellular signaling pathways regulating secretory activity, cell viability, steroidogenesis, proliferation, and apoptosis. On the other hand, while being metabolized in the body, amygdalin releases significant amounts of cyanide, which may lead to acute health hazard in those individuals who may be at risk. Despite some contradictions in the available data about benefits and toxic effects of amygdalin, its potential applicability at low doses may present a promising tool for regulation of various reproductive and other physiological processes including disease management primarily in cancer phytotherapy, animal production, medicine, and biotechnology. However, further research involving carefully designed dose-response studies is required to overcome the possible side effects of amygdalin and assure its safety as a therapeutic agent.

Life-Threatening Cyanide Intoxication after Ingestion of Amygdalin in Prehospital Care

Amygdalin is originally a natural cyanogenic glycoside available as a dietary supplement used in the alternative treatment of cancer patients. Amygdalin hydroxylates to toxic cyanide in the body, which can cause life-threatening intoxication. The case report presents a 72-year-old patient with life-threatening cyanide poisoning after ingesting a dietary supplement containing amygdalin identified in prehospital care, which was successfully treated with hydroxocobalamin.

Amygdalin - A pharmacological and toxicological review

ETHNOPHARMACOLOGICAL RELEVANCE

Amygdalin is commonly distributed in plants of the Rosaceae, such as peach, plum, loquat, apple and bayberry, but most notably in the seeds (kernels) of apricot almonds. As a naturally aromatic cyanogenic compound, it has long been used in Asia, Europe and other regions for the treatment of various diseases including cough, asthma, nausea, leprosy and leukoderma. Importantly, in recent years, an increasing attention has been paid to its antitumor effect.

AIM OF THE STUDY

The paper aims to review the pharmacological activities and toxicological effects of amygdalin and provide a reference and perspective for its further investigation.

METHODS

Electronic databases including the Web of Science, Cochrane Library, PubMed, EMBASE, the Chinese Biological Medicine Database, China National Knowledge Infrastructure, Wanfang database and VIP information database were searched up to November 2019 to identify eligible studies. A meticulous review was performed, an in-depth analysis on the pharmacological activity and toxicology of amygdalin was conducted, and perspectives for future research were also discussed.

RESULTS

A total of 110 papers about in vitro/in vivo studies on amygdalin have been reviewed. Analysis on the data suggested that this compound presented pharmacological activities of anti-tumor, anti-fibrotic, anti-inflammatory, analgesic, immunomodulatory, anti-atherosclerosis, ameliorating digestive system and reproductive system, improving neurodegeneration and myocardial hypertrophy, as well as reducing blood glucose. In addition, studies revealed that amygdalin's toxicity was caused by its poisonous decomposite product of benzaldehyde and hydrogen cyanide after oral ingestion, toxicity of intravenous administration route was far less than the oral route, and it can be avoidable with an oral dose ranging from 0.6 to 1 g per day.

CONCLUSION

This paper has systematically reviewed the pharmacology and toxicology of amygdalin and provided comprehensive information on this compound. We hope this review highlights some perspectives for the future research and development of amygdalin.

Metabolism and Pharmacokinetics of Phytochemicals in the Human Body

Background:

Phytochemicals are obtained from various plants and used for the treatment of diseases as both traditional and modern medicines. Poor bioavailability of phytochemicals is a major concern in applying phytochemicals as a therapeutic agent. It is, therefore, necessary to understand the metabolism and pharmacokinetics of phytochemicals for its implication as a therapeutic agent.

Methods:

Articles on the metabolism of phytochemicals from the PubMed database. The articles were classified into the digestion, absorption, metabolism, excretion, toxicity, and bioavailability of phytochemicals and the effect of gut microbiota on the metabolism of phytochemicals.

Results:

The metabolism of each phytochemical is largely dependent on the individual's digestive ability, membrane transporters, metabolizing enzymes and gut microbiota. Further, the form of the phytochemical and genetic make-up of the individual greatly influences the metabolism of phytochemicals.

Conclusion:

The metabolism of phytochemicals is mostly depended on the form of phytochemicals and individualspecific variations in the metabolism of phytochemicals. Understanding the metabolism and pharmacokinetics of phytochemicals might help in applying plant-based medicines for the treatment of various diseases.

Long-term peroral administration of bitter apricot seeds influences cortical bone microstructure of rabbits

Apricot seeds due to the presence of cyanogenic glycoside amygdalin belong to the popular "alternative cancer cures", although anticancer effect of amygdalin remains controversial. This in vivo study points to the effect of long-term peroral administration of bitter apricot seeds on bone microstructure of rabbits since chronic amygdalin toxicity in relation to bone parameters has not been investigated yet. Rabbits (n = 16) were randomly divided into four experimental groups of 4 animals each. Three experimental groups S1, S2 and S3 received commercial feed for rabbits mixed with crushed bitter apricot seeds at doses 60, 300 and 420 mg/kg bw during five months, respectively. The control (C) group received no apricot seeds. The long-term consumption of apricot seeds had no impact on total body weight, femoral weight and femoral length of rabbits. Also, microcomputed tomography (3D analysis) of cortical and trabecular bone tissues did not reveal any significant impact of amygdalin toxicity on relative bone volume, BMD, cortical bone thickness, bone surface, trabecular number, thickness, and their separation. On the other hand, histological (2D) analysis demonstrated evident changes in cortical bone microstructure consistent with a decreased density of secondary osteons in the middle part of substantia compacta due to a replacement of Haversian bone tissue by plexiform bone tissue, vasoconstriction in the primary osteons' vascular canals, Haversian canals, and decreased sizes of secondary osteons in rabbits from S1, S2 and S3 groups. These negative changes are associated with different vascularization and biomechanical properties of cortical bones.

Toxicity and Toxicokinetics of Amygdalin in Maesil ( Prunus mume) Syrup: Protective Effect of Maesil against Amygdalin Toxicity

Maesil ( Prunus mume, green plum)-based products have been widely used in Asian cooking, which may contain amygdalin enzymatically converted to hydrogen cyanide after oral ingestion. In this study, the toxicity of Maesil syrups matured with and without Maesils was evaluated by focusing on relationship between amygdalin toxicity and its metabolic change. The cytotoxicity of amygdalin was highly related to its metabolites converted by β-glucosidase, and the metabolic change was retarded in Maesil syrup. Toxicokinetics revealed extremely low oral absorption and short half-life of amygdalin standard and Maesil syrups, and delayed metabolic change of amygdalin in Maesil syrup was found. It seems that complex Maesil syrup components play roles against amygdalin degradation. Maesil syrup matured with Maesils had higher total polyphenols, lower amygdalin, and shorter half-life in bloodstream than Maesil syrup without Maesils, suggesting more safety benefit. No significant oral toxicity of Maesil syrups was found after 14-day repeated administration, implying their safety.