Phytochemical, Toxicological, Biochemical and Haematological Studies on Avocado (Persea americana) in Experimental Animals

Ethnomedicinal Uses, Phytochemistry, and Anticancer Potentials of African Medicinal Fruits: A Comprehensive Review

Africa is home to diverse medicinal plants that have been used for generations for the treatment of several different cancers and, presently, they are gaining interest from researchers as promising approaches to cancer treatment. This review aims to provide a comprehensive review of dietary and medicinal African fruits including their traditional uses, botanical description, ethnobotanical uses, bioactive phytochemical compositions, and anticancer properties investigated to date in vitro, in vivo, and in clinical studies. Data on recent updates concerning the traditional uses and anticancer properties of these fruits were collected from a myriad of available publications in electronic databases, such as Web of Science, PubMed, ScienceDirect, Scopus, SpringerLink, and Google Scholar. The results suggest that approximately 12 native or commercially grown African fruits belonging to different plant species, including Tribulus terrestris, Xanthium strumarium, Withania somnifera, Xylopia aethiopica, Abelmoschus esculentus, Carissa macrocarpa, Carpobrotus edulis, Syzygium cumini, Kigelia Africana, Annona muricata, Persea americana, and Punica granatum, have been reported for their potential as treatment options for the management of cancer. We further found that approximately eight different fruits from native plant species from Africa, namely, Sclerocarya birrea, Dovyalis caffra, Parinari curatellifolia, Mimusops caffra, Carpobrotus edulis, Vangueria infausta, Harpephyllum caffrum, and Carissa macrocarpa, have been widely used for the traditional treatment of different ailments but somehow failed to gain the interest of researchers for their use in anticancer research. In this review, we show the potential use of various fruits as anticancer agents, such as Tribulus terrestris, Xanthium strumarium, Withania somnifera, Xylopia aethiopica, Abelmoschus esculentus, Carissa macrocarpa, Carpobrotus edulis, Syzygium cumini, Kigelia Africana, Annona muricata, Persea americana, and Punica granatum; unfortunately, not enough reported research data have been published to gain thorough mechanistic insights and clinical applications. Additionally, we discuss the possibility of the utilization of potential phytochemicals from fruits like Persea americana and Punica granatum in anticancer research, as well as future directions.

Anti-obesity Effect of Bioengineered Silver Nanoparticles Synthesized from Persea americana on Obese Albino Rats

BACKGROUND

Obesity is an immoderate or abnormal accretion of fat or adipose tissue in the body that is prone to damage the health of mankind. Persea americana (Avocados) is a nutritious fruit known for its several health benefits. The current research was planned to evaluate the anti-obesity activity of bioengineered Silver Nanoparticles (AgNPs) against a high-fat diet (HFD) treated obese albino rats.

METHODS

AgNPs were synthesized and characterized for the Phytochemical constituents, UV-vis Spectroscopy, FTIR, SEM and XRD. Furthermore, the lipid profile in serum, biochemical parameters and histopathological changes in tissues of albino rats were determined.

RESULTS

The present study revealed the presence of tannins, flavonoids, steroids and saponins, carbohydrates, alkaloids, phenols and glycosides. The peak was disclosed at 402 nm in UV-vis spectroscopy, confirming the synthesis of AgNPs. FTIR analysis showed two peaks at 3332.25 cm-1 which correspond to the O-H stretch of the carboxylic acid band, and 1636.40 cm-1 represents the N-H stretch of the amide of proteins, respectively. This result confirms their contribution to the capping and stabilization of AgNPs. The XRD results confirm the crystalline nature of AgNPs, and SEM results indicated that the synthesized AgNPs were spherical. Further, the results of the current study showed the improved lipid profile and biochemical parameters in rats supplemented with methanolic pulp extract of Persea americana AgNPs when compared with other experimental groups. The histopathological findings displayed improved results with reduced hepatocyte degradation under the influence of AgNPs treatment.

CONCLUSION

All the experimental evidence indicated the possible anti-obesity effect of silver nanoparticles synthesized from the methanolic pulp extract of Persea americana.

Protective effects of Persea americana fruit and seed extracts against chemically induced liver cancer in rats by enhancing their antioxidant, anti-inflammatory, and apoptotic activities

This study aims to explore the chemopreventive mechanisms of hydroethanolic extracts from avocado (Persea Americana) in diethylnitrosamine (DEN)/2-acetylaminofluorene (2AAF)-induced hepatocarcinogenesis. Chemical induction of hepatocarcinogenesis was induced by intraperitoneal injection of DEN at 150 mg/kg body weight (b.w.) twice a week for a fortnight, followed by oral administration of 2AAF at 20 mg/kg b.w. four times a week for 3 weeks. Rats administered DEN/2AAF were orally treated with hydroethanolic extracts of avocado fruits and seeds at a dose of 50 mg/kg b.w. every other day for 20 weeks. Moreover, rats administered DEN/2AAF and treated with avocado extracts revealed a marked decrease in liver enzyme activities, total bilirubin levels, and elevated liver tumor markers, but revealed an increase in total protein and albumin levels. The hepatocytes with hyperchromatic and bile duct cystadenoma observed in the liver of rats administered DEN/2AAF were reduced due to treatment with avocado extracts. Furthermore, the treatments prevented the elevation of lipid peroxidation levels and ameliorated the lowered glutathione peroxidase, glutathione-S-transferase, superoxide dismutase activities, and glutathione content in the liver tissues. Also, antigen Ki-67, cyclooxygenase-2, and nuclear factor kappa-B expression levels were decreased, but of the suppressor proteins p53 and BAX levels were increased in the liver of rats administered DEN/2AAF and treated with avocado extracts. In conclusion, the current results demonstrated that avocado extracts could abate hepatocarcinogenesis in rats administered DEN/2AAF through activation of antioxidant, anti-inflammatory, and apoptotic properties.

Ethnopharmacological Study of the Medicinal Plants Used in the Treatment of Sickle Cell Anemia in the West Region of Cameroon

Background

Sickle cell anemia (SCA) or sickle cell disease (SCD) is a genetic disease associated with increased morbidity and mortality in Africa and other developing nations. Therefore, modern and traditional remedies are being introduced for use in the treatment and management of this disease. This is because safe, effective, and inexpensive therapeutic agents are urgently needed for the treatment of this disease in Africa and other developing nations.

Objective

The purpose of this study is to identify medicinal plant species commonly used by traditional healers in the treatment of sickle cell patients across some localities in the west region of Cameroon. Material and Methods. The ethnopharmacological survey was carried out in several districts within some localities of the western region of Cameroon. The survey was based on a semistructured questionnaire that was administered to 17 traditional healers and 62 sickle cell patients. It took place between November 2018 and March 2019. Personal information of participants and plant therapy data were gathered. Plants were identified at the National Herbarium of Cameroon. Literature review determined pharmacological effects and phytochemical compounds of the identified plants. Data were generally analysed using Epi Info 7 software for Windows.

Results

Twelve medicinal plant species belonging to 10 families are being used in the treatment of sickle cell anemia across the study sites. Euphorbiaceae is the dominant family with three plant species. Bark (39.3%) and seeds (35.7%) are the most used plant parts, which get administered through maceration, decoction, and chewing in water. According to the literature review, the identified plants have pharmacological effects and phytochemical compounds (especially polyphenols and alkaloids) that signify the presence of antioxidant compounds, which may possess an antisickling activity. There is therefore a need to conduct another study to scientifically validate (in vitro) antisickling properties of these plants.

Conclusion

This study has revealed promising medicinal plants that are currently applied in the traditional treatment of sickle cell anemia. Although still inconclusive, the association of pharmacological effects and phytochemical compounds with these medicinal plants justifies their use in traditional pharmacopoeia.

Promising Nutritional Fruits Against Cardiovascular Diseases: An Overview of Experimental Evidence and Understanding Their Mechanisms of Action

Cardiovascular diseases (CVDs) are one of the leading causes of morbidity and mortality in both developed and developing countries, affecting millions of individuals each year. Despite the fact that successful therapeutic drugs for the management and treatment of CVDs are available on the market, nutritional fruits appear to offer the greatest benefits to the heart and have been proved to alleviate CVDs. Experimental studies have also demonstrated that nutritional fruits have potential protective effects against CVDs. The aim of the review was to provide a comprehensive summary of scientific evidence on the effect of 10 of the most commonly available nutritional fruits reported against CVDs and describe the associated mechanisms of action. Relevant literatures were searched and collected from several scientific databases including PubMed, ScienceDirect, Google Scholar and Scopus. In the context of CVDs, 10 commonly consumed nutritious fruits including apple, avocado, grapes, mango, orange, kiwi, pomegranate, papaya, pineapple, and watermelon were analysed and addressed. The cardioprotective mechanisms of the 10 nutritional fruits were also compiled and highlighted. Overall, the present review found that the nutritious fruits and their constituents have significant benefits for the management and treatment of CVDs such as myocardial infarction, hypertension, peripheral artery disease, coronary artery disease, cardiomyopathies, dyslipidemias, ischemic stroke, aortic aneurysm, atherosclerosis, cardiac hypertrophy and heart failure, diabetic cardiovascular complications, drug-induced cardiotoxicity and cardiomyopathy. Among the 10 nutritional fruits, pomegranate and grapes have been well explored, and the mechanisms of action are well documented against CVDs. All of the nutritional fruits mentioned are edible and readily accessible on the market. Consuming these fruits, which may contain varying amounts of active constituents depending on the food source and season, the development of nutritious fruits-based health supplements would be more realistic for consistent CVD protection.

Amelioration of cyclophosphamide toxicity via modulation of metabolizing enzymes by avocado (Persea americana) extract

OBJECTIVES

Cyclophosphamide (CPA) is highly effective in treating several human tumours and autoimmune disorders; but, it triggers deleterious side effects. Avocado, Persea americana (Mill.), is a widely consumed fruit with pronounced nutritional and medicinal value. Though many studies examined the protective mechanisms of natural products against CPA toxicity, almost none investigated the modulation of CPA metabolism as a potential underlying mechanism for protection. Here, we investigated the modulating effect of avocado extract (AE) on certain CPA metabolizing enzymes and its correlation with the extent of CPA-induced pulmonary toxicity and urotoxicity.

METHODS

Rats received oral AE (0.9 g/kg body weight/day) 7 days before a single CPA injection (150 mg/kg body weight) and continued AE intake for 2, 7 or 28 days to study three phases of CPA-induced urotoxicity and pulmonary toxicity.

KEY FINDINGS

CPA acutely elevated then reduced hepatic microsomal cytochrome P450 2B6 (CYP2B6) content and significantly suppressed bladder and lung glutathione-S-transferase activity. Furthermore, CPA elevated lung myeloperoxidase activity, DNA content and hydroxyproline level and bladder blood content. AE ameliorated CPA-induced derangements through suppression of CYP2B6 and myeloperoxidase and augmentation of glutathione-S-transferase activity in CPA-treated rats.

CONCLUSIONS

AE modulation of CPA metabolizing enzymes and potential anti-inflammatory effect may mitigate CPA-induced toxicity.

Avocado oil: Production and market demand, bioactive components, implications in health, and tendencies and potential uses

Avocado is a subtropical/tropical fruit with creamy texture, peculiar flavor, and high nutritional value. Due to its high oil content, a significant quantity of avocado fruit is used for the production of oil using different methods. Avocado oil is rich in lipid-soluble bioactive compounds, but their content depends on different factors. Several phytochemicals in the oil have been linked to prevention of cancer, age-related macular degeneration, and cardiovascular diseases and therefore have generated an increase in consumer demand for avocado oil. The aim of this review is to critically and systematically analyze the worldwide production and commercialization of avocado oil, its extraction methods, changes in its fat-soluble phytochemical content, health benefits, and new trends and applications. There is a lack of information on the production and commercialization of the different types of avocado oil, but there are abundant data on extraction methods using solvents, centrifugation-assisted aqueous extraction, mechanical extraction by cold pressing (varying concentration and type of enzymes, temperature and time of reaction, and dilution ratio), ultrasound-assisted extraction, and supercritical fluid to enhance the yield and quality of oil. Extensive information is available on the content of fatty acids, although it is limited on carotenoids and chlorophylls. The effect of avocado oil on cancer, diabetes, and cardiovascular diseases has been demonstrated through in vitro and animal studies, but not in humans. Avocado oil continues to be of interest to the food, pharmaceutical, and cosmetic industries and is also generating increased attention in other areas including structured lipids, nanotechnology, and environmental care.

Avocado fruit and by-products as potential sources of bioactive compounds

The increased demand for avocado, and therefore production and consumption, generate large quantities of by-products such as seeds, peel, and defatted pulp, which account for approximately 30% of fruit weight, and which are commonly discarded and wasted. The present review focuses on various compounds present in avocado fruit and its by-products, with particular interest to those that can be potentially used in different industrial forms, such as nutraceuticals, to add to or to formulate functional foods, among other uses. Main molecular families of bioactive compounds present in avocado include phenolic compounds (such as hydroxycinnamic acids, hydroxybenzoic acids, flavonoids and proanthocyanins), acetogenins, phytosterols, carotenoids and alkaloids. Types, contents, and possible functions of these bioactive compounds are described from a chemical, biological, and functional approach. The use of avocado and its by-products requires using processing methods that allow highest yield with the least amount of unusable residues, while also preserving the integrity of bioactive compounds of interest. Avocado cultivar, fruit development, ripening stage, and processing methods are some of the main factors that influence the type and amount of extractable molecules. The phytochemical diversity of avocado fruit and its by-products make them potential sources of nutraceutical compounds, from which functional foods can be obtained, as well as other applications in food, health, pigment, and material sectors, among others.

Effects of Avocado (Persea americana) on Metabolic Syndrome: A Comprehensive Systematic Review

Metabolic syndrome (MetS) is a clustering of risk factors including high blood glucose, dyslipidemia, hypertension, and obesity that lead to the increased risk of type 2 diabetes mellitus and cardiovascular diseases (CVDs), which are among leading causes of death in the world. Metabolic syndrome increases the risk of type 2 diabetes mellitus and CVDs by approximately five and three folds, respectively. Therefore, it is of vital importance to manage such conditions with herbal options which have less undesirable adverse effects and may be more efficacious in comparison with synthetic options. Avocado is a well-known source of carotenoids, minerals, phenolics, vitamins, and fatty acids. The lipid-lowering, antihypertensive, antidiabetic, anti-obesity, antithrombotic, antiatherosclerotic, and cardioprotective effects of avocado have been demonstrated in several studies. In this review, we aimed to find out avocado's pharmacological effects on different components of MetS. Moreover, this review report is performed on the MetS effects of peel, seed, flesh, and leaves of avocado. Copyright © 2017 John Wiley & Sons, Ltd.