Antimicrobial activity and phytochemical screening of Arbutus unedo L

Antioxidant and Biological Activity of Mexican Madroño Fruit (Arbutus arizonica)

The fruit of the Mexican madroño (Arbutus arizonica) has been consumed since pre-Columbian times by North American tribes and native groups in Mexico. Despite this, reports on its chemical composition and biological activity are limited. This work aims to determine the antioxidant, antiproliferative, and digestive enzyme inhibition activities of the methanol amberlite-retained extract of Mexican madroño. Results showed that madroño fruit is rich in antioxidants: DPPH (EC50 = 0.89 ± 0.03 mg/mL), TEAC (1078 ± 4.9 μM/g), and hemolysis inhibition (IC50 = 358.07 μg/mL), with high phenolic and flavonoid content at 15.92 ± 3.2 mg GAE/g and 4.33 ± 0.3 mg CA/g, respectively. Using analytical chromatography, gallic acid, vanillic acid, chlorogenic acid, ferulic acid, quercetin, and rutin were quantified. The extract also showed α-glucosidase inhibition (IC50 = 3.1 ± 0.17 mg/mL), but no inhibition against α-amylase and lipase (>5 mg/mL), while showing antiproliferative activity against HeLa, HT-29, and MCF-7 cancer cell lines. These results point towards an interesting potential for the fruit of the A. arizonica as chemopreventive and hold potential for elaborating functional foods.

The Application of Probiotic Bacteria from Strawberry (Fragaria ananassa × Duch.) in the Fermentation of Strawberry Tree Fruit (Arbutus unedo L.) Extract

The search for unexplored plant resources that would provide a good basis for the development of novel probiotic functional foods is rapidly increasing. In this context, the strawberry tree fruit (Arbutus unedo L.) is particularly interesting, as it is rich in numerous antioxidant bioactive compounds that have been shown to be beneficial to health, but have not yet found industrial applications. In this work, the probiotic characterization of lactic acid bacteria strain Lactiplantibacillus plantarum DB2, isolated from strawberries (Fragaria ananassa × Duch.), was performed. The tested strain proved to be safe to use, displaying no antibiotic resistance or hemolytic activity. Due to its proven probiotic potential during simulated gastrointestinal transit, its antimicrobial activity, and its coaggregation with pathogens, it was selected for fermentation of an aqueous Arbutus unedo L. extract, which was subsequently microencapsulated and freeze-dried to extend its shelf life and preserve its functional properties. The antioxidant activity of the ferment obtained was maintained (80%), while after microencapsulation and freeze-drying, about 50% and 20% of the antioxidant activity was retained, respectively. In conclusion, this study demonstrates for the first time the application of probiotics isolated from strawberries in the fermentation of strawberry tree extract and monitors the antioxidant activity during post-fermentation formulation, paving the way for a potential industrial application of this underutilized plant.

Use of Strawberry Tree (Arbutus unedo) as a Source of Functional Fractions with Biological Activities

Arbutus unedo, commonly named 'strawberry tree' (ST), is a Mediterranean native plant that represents a relevant source of biologically active fractions and compounds. ST fruits, traditionally used with culinary and medicinal purposes, along with other components (leaves, roots, honeys, etc.), have been subjected to varied extraction procedures to obtain enriched and bioactive products. This work reviewed the scientific literature, searching for studies that evaluated the potential health implications of ST fractions and attending to the tested biological activities (antioxidant, antiproliferative, hypoglycemic, immune-modulatory, antihypertensive, antimicrobial, etc.), the part of the tree, the experimental model, the specific bioactive compounds and the selected extraction protocol. Furthermore, the strengths and weaknesses of the current state of the published evidence were critically analysed. Although in vitro results demonstrated the potential of ST fractions, further research is encouraged in order to obtain in vivo evidence (animal and clinical studies), assess additional activities (hypocholesterolemic, microbiome-modulatory), maximize the use of advanced extraction technologies, purify and isolate specific bioactive compounds and broaden the analysis investigating phenolic and non-phenolic molecules and their bioavailability.

An Endemic Plant of the Mediterranean Area: Phytochemical Characterization of Strawberry Tree (Arbutus unedo L.) Fruits Extracts at Different Ripening Stages

This work focused on the extraction, quantification, and characterization of bioactive compounds of Arbutus unedo L. fruits, comparing the results obtained from the different ripening states. Extractions were performed by different methods (such as maceration extraction and ultrasonic extraction) and food grade solvents (aqueous and hydroalcoholic solvents) in each of the all ripening states (four states considered, associated with four different colors, i.e., green, yellow, orange, and red). The presence of (poly)phenols was quantified and characterized, and scavenging activity was determined by the Folin–Ciocâlteu reagent and the DPPH method, respectively. The content of bioactive compounds was characterized by LC-MS/MS, such as multiple reaction monitoring (MRM) mass spectrometry. The results showed that ultrasound-assisted extraction (UAE) performed better than maceration extraction; ethanol–water mixture extracts showed a more positive effect than the use of aqueous extracts regarding the content of total phenolic compounds. Overall, the total phenolic compounds in the EtOH:H₂O mixture at a ratio of 7:3 (v:v) were higher than that of the other solvents for both extraction methods. Some bioactive molecules were characterized for the first time in the extracts of A. unedo. The chemical profile of the strawberry tree extracts depended on the degree of fruit ripeness. The results suggest that A. unedo fruits may be of great interest for food and nutraceutical applications.

Arbutus unedo leaf extracts as potential dairy preservatives: case study on quark cheese

The plant kingdom is an endless source of molecules that can be applied in almost all realms of society. The food industry has profited from the use of plants and their derived materials for many decades. Recently, the food industry has been looking into plants to find different ways of either preserving, coloring or sweetening foods. In this work, leaf extracts of Arbutus unedo L. obtained by dynamic maceration and ultrasound assisted extraction with prior optimization of their extraction conditions through the response-surface methodology, were incorporated in quark cheese as natural preservatives and analyzed over 8 days of shelf-life. Both extracts showed antioxidant activity with no toxicity towards primary cell lines at the maximum tested concentration, as well as antibacterial activity, especially against Gram-positive strains. After their incorporation in quark cheese, no significant changes were observed in the nutritional profile and physical traits of the quark cheeses, while the microbial load was highly reduced in the cheese, especially using the extracts obtained from dynamic maceration. Thus, leaf extracts of A. unedo can be promising candidates for use in the food industry as natural preservatives.

Comparative Study on the Phenolic Fingerprint and Antioxidant Activity of Strawberry Tree (Arbutus unedo L.) Leaves and Fruits

The strawberry tree (Arbutus unedo L., Ericaceae family) is an evergreen Mediterranean shrub whose leaves and fruits are used in traditional medicine due to their antioxidant, antimicrobial, antidiabetic, diuretic, and antiproliferative properties. The health benefits are mainly attributed to the presence of phenolic compounds. The aim of this study was to compare the phenolic profiles, total phenolic content (TPC), and radical scavenging activity (RSA) of A. unedo leaves and fruits collected at two locations in Croatia. Phenolic profiles were identified using an ultra-high-performance liquid chromatograph (UHPLC) coupled with a hybrid mass spectrometer (LTQ Orbitrap MS). TPC was determined by Folin–Ciocalteu’s assay, while RSA was investigated using DPPH reagent. A total of 64 phenolics (60 and 42 compounds in leaves and fruits, respectively) were identified. Hyperoside and flavan-3-ols were predominant compounds in leaves, while gallocatechin and catechin were the major compounds found in fruits. To the authors’ knowledge, 16 and 5 phenolics in leaves and fruits, respectively, were reported for the first time. Principal component analysis (PCA) showed that UHPLC-LTQ Orbitrap MS could be used to identify which phenolics were able to discriminate samples regarding plant tissue and geographical origin. TPC in leaves and fruits were in the ranges of 67.07–104.74 and 16.78–25.86 mg gallic acid equivalents (GAE)/g dried weight (dw), respectively. RSA for leaves and fruits were in the ranges of 408.92–430.98 and 74.30–104.04 μmol Trolox equivalents (TE)/g dw, respectively. The number of identified phenolics was lower in fruits compared to leaves. Such a large number of bioactive phenolics identified and the strong antioxidant activity pointed to A. unedo as a promising health-promoting plant and natural food preservative.

The Beekeeping State and Inventory of Mellifero-Medicinal Plants in the North-Central of Morocco

This study aims to determine the diversity of melliferous plants and to recognize the state of beekeeping in the Fez-Meknes region in Morocco. We conducted a questionnaire for beekeepers that set up their hives in the prefectures and provinces of the region, and we have studied the pharmacological evidence of the most preferred plants by beekeepers to assess its medicinal values. The results indicate that honey, bee pollen, bee bread, royal jelly, propolis, bee wax, bee venom, and bee queens are produced in this region with different percentages, and 102 plants belonging to 32 families were obtained in the inventory of melliferous plants; the most represented families were Asteraceae and Lamiaceae (13.73% each) followed by Rosaceae (8.82%). Among these 102 plants identified, 79 plants provide nectar and pollen for bees, 16 plants provide only pollen, 3 plants provide only nectar, 35 plants are resinous, and 6 plants provide honeydew for bees. The outcome of this study will contribute to the valuation of melliferous plants and help to establish a practical guide for the development of the beekeeping sector as an agricultural economic approach.

Physico-Chemical and Phytochemical Characterization of Moroccan Wild Jujube "Zizyphus lotus (L.)" Fruit Crude Extract and Fractions

Wild jujube “Ziziphus lotus (L.) Desf.” belongs to the Rhamnaceae family and is a traditionally herbaceous medicinal plant. It is very common in arid and semi-arid regions and is currently used for its antidiabetic, sedative, analgesic, anti-inflammatory and hypoglycemic activities. The aim of the present work was to characterize the physico-chemical properties and the phytochemical profile of wild jujube sample collected from the Guercif region, in order to determine the polyphenolic compounds and the antioxidant ability Analyses were carried out directly after the harvest for the determination of pH, refractive index, total soluble solid (°Brix), dry matter, sugar/acidity, total sugars, reducing sugars, as well as lipid and protein content. Results showed that the investigated fruit is acidic (pH 4.9 ± 0.23) and rich in sugars (80.2 g/100 g ± 3.81). The GC-MS analysis of the fruit revealed a number of volatile compounds, as many as 97, belonging to different chemical classes. The HPLC-DAD-ESI/MS analysis showed the presence of a total of 20 polyphenolic compounds in both EtOAc and MeOH-water extracts. Among them, p-Hydroxybenzoic acid was the most abundant in the EtOAc extract (185.68 µg/100 mg ± 0.5) whereas Quercetin 3-O-rhamnoside-7-O-glucoside was found in higher amounts in the MeOH-water extract (25.40 µg/100 mg ± 0.5). These components have medical interest, notably for human nutrition, as well as health benefits and therapeutic effects. Therefore, Moroccan jujube “Zizyphus lotus (L.)” fruit may have potential industrial applications for food formulations.

Arbutus unedo L., (Ericaceae) inhibits intestinal glucose absorption and improves glucose tolerance in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Arbutus unedo L., (Ericaceae) is one of the most traditional plants commonly used to treat diabetes in people living in Eastern Morocco region particularly in Taza and Beni Mellal.

AIM OF THE STUDY

The aim of the study was to find if there is a scientific support to the ethnopharmacological relevance use of Arbutus unedo L., roots bark (AU) to treat diabetes.

MATERIALS AND METHODS

We studied the effects of crude aqueous extract of AU on intestinal glucose absorption using short-circuit current technique in vitro and oral glucose tolerance test in vivo.

RESULTS

The aqueous extract of AU (10 µg/mL to 1 mg/mL) induced concentration-dependent inhibition of sodium-dependent glucose transport across isolated mouse jejunum. The maximal inhibition was obtained with 1 mg/mL, which exhibited more than 80% of the Phloridzin inhibition with an IC₅₀ close to 216 µg/mL. A 6-week AU ingestion (2 g/(kg day)), improved oral glucose tolerance as efficiently as metformin (300 mg/(kg day)). Arbutus unedo L. and metformin also reduced body weight.

CONCLUSIONS

Arbutus unedo L. roots bark aqueous extract directly inhibited the electrogenic intestinal absorption of glucose in vitro. In addition it improved oral glucose tolerance and lowered body weight in rats after chronic oral administration in vivo. These results add a scientific support to the ethnopharmacological relevance use of Arbutus unedo L. roots bark to treat diabetes.

Arbutus species (Ericaceae) as source of valuable bioactive products

In addition to nutrients, plant foods contain compounds that may provide additional health benefits improving the quality of life. Species from Arbutus genus (Ericaceae) represent a promising source of healthy phytochemicals. Bioactive compounds including such as anthocyanins, iridoids, phenols, triterpenes, sterols, and fatty acids are reported from Arbutus species. Some Arbutus species revealed promising biological activities including antioxidant, anti-inflammatory, anti-proliferative, anti-diabetic, and antimicrobial activities, and deserve for that reason further consideration for new drug discovery. However, only few species are investigated scientifically for their chemical profile and biological activities. The aim of this article is to summarize the current knowledge of the components and biological properties of Arbutus species common in Mediterranean area, as well as the future prospects on their applications as potentially valuable products.

Arbutus unedo L.: From traditional medicine to potential uses in modern pharmacotherapy

ETHNOPHARMACOLOGICAL RELEVANCE

Arbutus unedo L., the strawberry tree (Ericaceae family) is of increasing interest because of its common traditional, industrial, chemical and pharmaceutical uses. The plant is a typical evergreen plant of the Mediterranean basin, as well as of other regions with hot summers and mild rainy winters. This review covers the studies relevant to Arbutus unedo L. utilization in the current pharmacological therapy.

MATERIALS AND METHODS

The available information on traditional uses, phytochemistry and biological activities of Arbutus unedo L. was collected from scientific databases through a search using the keywords 'Arbutus unedo L.' and/or 'strawberry tree' in 'Google Scholar', 'Pubmed', 'Sciencedirect', 'SpringerLink', 'Web of Science - Clarivate Analytics' and 'Wiley'. Unpublished Ph.D. and M.Sc. dissertations were also consulted for chemical composition, biological activities and traditional uses of Arbutus unedo L. and for manual search of additional references.

RESULTS

The fruits of the plant have been traditionally used as antiseptics, diuretics and laxatives in folk medicine, while the leaves have been used due to their diuretic, urinary antiseptic, antidiarrheal, astringent, depurative and antihypertensive properties. According to the scientific literature survey, different extracts obtained from Arbutus unedo L. have demonstrated a high pharmacological potential due to their in vitro and preclinical antibiotic, antifungal, antiparasitic, antiaggregant, antidiabetic, antihypertensive, anti-inflammatory, antitumoral, antioxidant, and spasmolytic properties.

CONCLUSION

This review suggests that A. unedo is a promising source of phytopharmaceutical products. The potential advantages of Arbutus unedo are related with the presence of polyphenolic compounds in its composition. However, further studies are needed to ascertain some profitable effects in humans. The beneficial effects associated with this shrub suggest that Arbutus unedo can be used for the development of new drugs to treat diseases such diabetes, hypertension, among others. Nonetheless, the safety of the Arbutus unedo compounds should also be examined.

Antibacterial activity of ethanolic extract and compounds from fruits of Tectona grandis (Verbenaceae)

Background

Well known as teak, Tectona grandis is widely used in African folk medicine for its pharmacological relevance. In Cameroon, this species is a reputed laxative in the Northern Region while in the Western Region, it is used in the treatment of skin diseases and diarrhoea.

Materials and methods

Separation and isolation of compounds were performed using different chromatographic methods while their structures were elucidated by spectroscopic techniques including MS and NMR, and by comparison of data with those reported in the literature. Isolated compounds as well as crude ethanol extract were tested for their antibacterial activities using broth micro-dilution method against four Gram negative bacteria strains Escherichia coli (ATCC 8739), Pseudomonas aeruginosa (PA 01), Klebsiella pneumonia (ATCC 11296) and Escherichia aerogenes (ATCC 13048).

Results

Three known compounds were isolated, including two quinones and one triterpene. They were identified as tectograndone (1), 6-methyl-1,4-dihydroxyanthraquinone (2), and 2β-hydroxyursolic acid (3) respectively. Crude ethanol extract showed good activity against the bacteria strains tested with MIC of 64–256 μg/mL. Among the isolated metabolites, 6-methyl-1,4-dihydroxyanthraquinone exhibited a strong activity against Escherichia aerogenes with MIC of 16 μg/mL, while tectograndone showed a moderate activity against Escherichia coli with MIC of 32 μg/mL. The antibacterial screening of the fruits of this plant as well as that of compounds 1 and 2 is reported herein for the first time.

Conclusion

The research work presented here shows that Tectona grandis fruits possess compounds which could be developed in the treatment of bacterial diseases.

Polyacrylonitrile/Syzygium aromaticum hierarchical hydrophilic nanocomposite as a carrier for antibacterial drug delivery systems

A versatile, maneuverable electrospinning process was exploited to fabricate intertwined-heterostructure polyacrylonitrile (PAN) nanofibers by incorporating the essential oilSyzygium aromaticumfor antibacterial drug delivery systems.

PCL/PVA nanoencapsulated reinforcing fillers of steam exploded/autoclaved cellulose nanofibrils for tissue engineering applications

The process of extraction of cellulose nanofibrils by steam explosion followed by electrospinning with biodegradable polymers to yield PCL/PVA nanoencapsulated cellulosic reinforcing fillers for tissue engineering applications.

Arbutus unedo L.: chemical and biological properties

Arbutus unedo L. (strawberry tree) has a circum-Mediterranean distribution, being found in western, central and southern Europe, north-eastern Africa (excluding Egypt and Libya) and the Canary Islands and western Asia. Fruits of the strawberry tree are generally used for preparing alcoholic drinks (wines, liqueurs and brandies), jams, jellies and marmalades, and less frequently eaten as fresh fruit, despite their pleasing appearance. An overview of the chemical composition of different parts of the plant, strawberry tree honey and strawberry tree brandy will be presented. The biological properties of the different parts of A. unedo and strawberry tree honey will be also overviewed.

Encapsulation of therapeutic lavender oil in an electrolyte assisted polyacrylonitrile nanofibres for antibacterial applications

Electrospinning, a feasible nanotechnology, has been exploited to engineer polyacrylonitrile (PAN) nanofibrous mats enclosing a representative hydrophobic drug like essential oil of lavender.