Phenolic and tocopherol content of autumn olive (Elaeagnus umbellate) berries

Elaeagnus umbellata: A miraculous shrub with potent health-promoting benefits from Northwest Himalaya

Medicinal plants encompassing a series of bioactive compounds have gained significant importance for use in the treatment of different diseases. Of them, Elaeagnus umbellata Thunb. (Deciduous shrub found in dappled shade, and sunny hedge) exhibits high medicinal value, with a widespread distribution across the Pir Panjal region of the Himalayas. Fruits serve as an excellent source of vitamins, minerals, and other essential compounds that exhibits hypolipidemic, hepatoprotective, and nephroprotective effects. The phytochemical fingerprint of berries revealed them to have a high content of polyphenols (with major proportion of anthocyanins), followed by monoterpenes and vitamin C. Extract of fruits help in regulating the digestion and absorption of glucose and reduces inflammation and oxidative stress. The phytosterols upholding anticoagulant activity serve the purpose of causing decrease in angina and the blood cholesterol levels. Phytochemicals such as eugenol, palmitic acid, and methyl palmitate exhibit potent antibacterial activity against broad range of disease-causing agents. Additionally, a high percentage of essential oils attribute it with the property of being effective against heart ailments. The present study highlights the importance of E. umbellata in traditional medicinal practices, and summarizes the knowledge of its bioactive constituents and a snapshot vision of remarkable biological activities like antimicrobial, antidiabetic, antioxidant, etc towards understanding its role in the development of efficient drug regimens for use in the treatment of different diseases. It also underlines the need to explore the plant on nutritional aspects to strengthen the existing knowledge pertaining to health promoting potential of E. umbellata.

Fruit tree leaves as valuable new source of tocopherol and tocotrienol compounds

BACKGROUND

Nowadays it is highly important to find new, cheap and widely available sources of tocopherol and tocotrienol compounds, and leaves are promising unconventional sources. The main goal of this study was to extend the currently limited knowledge concerning tocopherol and tocotrienol isomers composition determined using ultra-high performance liquid chromatography with fluorescence detection analysis for various fruit tree leaves such as apple, pear, quince, apricot, peach, plum, sour cherry and sweet cherry. The leaves were collected 2 weeks after tree blooming and after fruit collection. Tocopherol and tocotrienol isomers were identified and quantified for the first time in all fruit tree leaves.

RESULTS

The total tocopherol content ranged from 203.34 to 260.86 μg g^-1 dry weight for spring leaves and from 23.83 to 235.62 μg g^-1 dry weight for autumn leaves and consisted mainly of α-tocopherol. The rest of the isomers of tocopherol and tocotrienols were also found, but in trace amounts. A significantly lower content of tocopherols and tocotrienols was detected in leaves after autumn collection of fruits compared to leaves collected after blooming. Among the analyzed leaves, time collected and species were significantly more important than their cultivars. Regarding quantification analysis, apricot > peach > > plums > apples leaves were identified as the best sources of tocopherols, and sweet and sour cherry leaves exhibited a lower content.

CONCLUSION

Fruit tree leaves are a novel significant source and good material for isolation of α-tocopherol for application in cosmetics, pharmaceuticals or in the food industry - for example, production of beverages or other functional foods. © 2021 Society of Chemical Industry.

Proanthocyanidins and Where to Find Them: A Meta-Analytic Approach to Investigate Their Chemistry, Biosynthesis, Distribution, and Effect on Human Health

Proanthocyanidins (PACs) are a class of polyphenolic compounds that are attracting considerable interest in the nutraceutical field due to their potential health benefits. However, knowledge about the chemistry, biosynthesis, and distribution of PACs is limited. This review summarizes the main chemical characteristics and biosynthetic pathways and the main analytical methods aimed at their identification and quantification in raw plant matrices. Furthermore, meta-analytic approaches were used to identify the main plant sources in which PACs were contained and to investigate their potential effect on human health. In particular, a cluster analysis identified PACs in 35 different plant families and 60 different plant parts normally consumed in the human diet. On the other hand, a literature search, coupled with forest plot analyses, highlighted how PACs can be actively involved in both local and systemic effects. Finally, the potential mechanisms of action through which PACs may impact human health were investigated, focusing on their systemic hypoglycemic and lipid-lowering effects and their local anti-inflammatory actions on the intestinal epithelium. Overall, this review may be considered a complete report in which chemical, biosynthetic, ecological, and pharmacological aspects of PACs are discussed.

Optimization of Osmotic Dehydration of Autumn Olive Berries Using Response Surface Methodology

Autumn olive fruits are a rich source of nutrients and functional compounds, making them functional foods against many diseases and cancers. To increase the consumption, its processing, and its transformation into new products would help spread them to the consumer’s table. In this study, after giving an overview of the physicochemical characteristics and the antioxidant activity, the objective was to optimize the osmotic dehydration (OD) of the berries. Response surface methodology was used to investigate the effect of dehydration factors: syrup concentration (30–70%), temperature (20–70 °C), and fruit-to-syrup ratio (1:10–2:10) on the water loss (WL), sugar gain (SG), weight reduction (WR), density (ρ), water activity (a_w), and total color change (ΔE) of fruits after 10 h of OD. Results obtained by employing Box–Behnken design (three variables, three levels), and significant terms of regression equations indicated that the syrup concentration and temperature variation are the most affecting factors on the previously mentioned independent variables (WL SG, WR, ρ, a_w, and ΔE). Fruits to syrup ratio appeared to have a significant effect only on WL. Under the optimum conditions found (70%, 70 °C, 1.8:10), the predicted values were 59.21%. 19.21%, 32.34%, 1.22 g/cm³, 0.850, and 3.65 for WL, SG, WR, ρ, a_w, and ΔE, respectively.

Curative Effect of Catechin Isolated from Elaeagnus Umbellata Thunb. Berries for Diabetes and Related Complications in Streptozotocin-Induced Diabetic Rats Model

In this study, catechin (CTN) isolated from Elaeagnus umbellata was evaluated for in vitro antioxidant potential and inhibition of carbohydrate digestive enzymes (α-amylase and α-glucosidase). The compound was also tested for its in vivo antidiabetic potential using Sprague-Dawley rats as experimental animals. The effects of various doses of catechin in STZ (Streptozotocin) induced diabetic rats on fasting blood glucose level, body weight, lipid parameters, hepatic enzymes, and renal functions were evaluated using the reported protocols. The CTN exhibited the highest percent antioxidant for free radical scavenging activity against DPPH and ABTS free radicals, and inhibited the activity of carbohydrate digestive enzymes (with percent inhibition values: 79 ± 1.5% α-amylase and 80 ± 1.1% α-glucosidase). Administration CTN and standard glibenclamide significantly decreased the fasting blood glucose level and increased the body weight in STZ-induced diabetic rats. CTN significantly decreased the different lipid parameters, hepatic, and renal function enzyme levels along with Hb1c level in diabetic rats, while significantly increasing the high-density lipoprotein (HDL) level with values comparable to the standard glibenclamide. Further, the altered levels of glutathione and lipid peroxides of liver and kidney tissues were restored (by CTN) to levels similar to the control group. CTN significantly increased the antioxidant enzyme activities, total content of reduced glutathione, and reduced the malondialdehyde (MDA) level in rat liver and kidney tissues homogenates, and also corrected the histopathological abnormalities, suggesting its antioxidant potential.

Phytochemical Characterization and Bioactivity Evaluation of Autumn Olive (Elaeagnus umbellata Thunb.) Pseudodrupes as Potential Sources of Health-Promoting Compounds

Autumn olive (Elaeagnus umbellata Thunb.) is a deciduous shrub tree widely distributed in Asia and Southern Europe and grown as ornamental species. It is locally used for human consumption, as relevant medical value is attributed to the berries. Information about its composition, especially concerning the characterization of bioactive and health-promoting compounds, is limited. The aim of the present study is to evaluate the main bioactive compounds and nutraceutical proprieties of autumn olive fruits, via high-performance liquid chromatography (HPLC) fingerprint and spectrophotometric analysis, in order to strengthen the knowledge about this underrated species and promote potential applications as a food supplement. Concerning nutraceutical traits, total polyphenolic content (325.366 ± 13.019 mg of gallic acid equivalents (mg GAE)/100 of fresh weight (g FW)) and total anthocyanin content (194.992 ± 0.817 mg of cyanidin-3-O-glucoside (mg C3G)/100 g FW) recorded considerable values. The phytochemical fingerprint revealed the presence 23 bioactive compounds. Polyphenols (65.56%) were the largest class, followed by monoterpenes (27.40%) and vitamin C (7.04%). Anthocyanins were the most represented compounds among polyphenols (71.9%). The antioxidant capacity (20.031 ± 1.214 mmol Fe2+/kg) was similar to that recorded for other small fruits with proven health-promoting properties. The present work underlined the potential of E. umbellata as a source of health-promoting bioactive compounds. Further studies should deepen the knowledge of nutraceutical aspects, which turned out to be interesting.

In Vitro Biological Activities of Fruits and Leaves of Elaeagnus multiflora Thunb. and Their Isoprenoids and Polyphenolics Profile

The objective of this study was in-depth identification of carotenoids and polyphenolic compounds in leaves and fruits of Elaeagnus multiflora Thunb. An additional aim was to assay their antioxidant and in vitro biological activities (the ability to inhibit pancreatic lipase, α-amylase, and α-glucosidase activity) of two cultivars: ‘Sweet Scarlet’ and ‘Jahidka’. Study results showed the presence of 70 bioactive compounds, including 20 isoprenoids and 50 polyphenols. The profile of identified bioactive compounds had not been examined in this respect until now. The total carotenoid, chlorophyll, and polyphenol levels and antioxidant activity of the foliar samples were virtually identical in both cultivars and clearly higher relative to those in the fruits. On the other hand, the ability to inhibit pancreatic lipase, α-amylase, and α-glucosidase activity of the fruits was clearly higher as compared to the leaves. The highest amount of phenolic acids, flavonols, and polymeric procyanidins was in the ‘Sweet Scarlet’ for fruit and leaves, while the highest amount of chlorophylls and carotenoids was in the ‘Jahidka’. The inhibition of α-amylase, α-glucosidase, and pancreatic lipase activities appeared to be better correlated with the carotenoid content, which warrants further studies of the possible anti-diabetic and anti-obesity actions of the major carotenoids found in the fruits (lycopene, phytoene, and lutein). In addition, strong correlation between antioxidant activity and phenols of E. multiflora Thunb. components can be effective in removing reactive oxygen species. The results of our study show that both the fruits and leaves of E. multiflora Thunb. can be important for health promotion through the diet and for innovating in the industry of functional food and (nutri)cosmetics.

Antioxidant Activity of Compounds Isolated from Elaeagnus umbellata Promotes Human Gingival Fibroblast Well-Being

Four new triterpenoid bidesmosidic saponins (1-4) and a sesquiterpenoid glucoside (5), together with nine known phenolic compounds (6-14), were isolated from the fruits of Elaeagnus umbellata. Their structures were elucidated using 1D and 2D NMR spectroscopy and mass spectrometry data. The antioxidant capability of the isolated compounds was evaluated in human gingival fibroblasts. Compound 6 decreased ROS production and promoted cell proliferation. It also counteracted the cell cycle blockade induced by a low concentration of H2O2 decreasing the expression of p21 and CDKN2A (p16INK4A). Compound 6 decreased the expression of inflammatory cytokines (IL-6 and IL-8) in response to inflammatory stimuli, supporting its possible use in periodontitis lesions.

Changes in the phenolic compositions of Elaeagnus umbellata and Sambucus lanceolata after in vitro gastrointestinal digestion and evaluation of their potential anti-diabetic properties

In this work, the phenolic composition of E. umbellata leaves and berries is reported. Berries were rich in flavonols, whereas leaves presented abundant flavonols and ellagitannins. Then, the enzyme-inhibitory properties, anti-glycation and antioxidant activities of E. umbellata and Sambucus lanceolata (its phenolic profile has been already established in a previous work) were tested by several in vitro assays and compared. The simulated gastrointestinal digestion resulted in a decrease on their phenolic composition. Nevertheless, both species still had the ability to inhibit aldose reductase activity and protein glycation and scavenge free radicals at the end of the process. Thus, the potential beneficial effects of E. umbellata and S. lanceolata seems to be kept to some extent after passage throughout the digestive system. Altogether, this study provides further insight into investigation of these species as dietary sources of bioactive compounds to lower the risk of type-2 diabetes and obesity.

Autumn olive (Elaeagnus umbellata Thunb.) berry reduces fasting and postprandial glucose levels in mice

BACKGROUND/OBJECTIVES

Fasting and postprandial hyperglycemia should be controlled to avoid complications of diabetes mellitus. This study investigated the effects of autumn olive (Elaeagnus umbellata Thunb.) berry (AOB) on fasting and postprandial hyperglycemia in mice.

MATERIALS/METHODS

In vitro α-glucosidase inhibitory effect of AOB was determined. Maltose solution (2 g/kg) with and without AOB extract at 500 mg/kg or acarbose at 50 mg/kg was orally administered to normal mice after overnight fasting and glucose levels were measured. To study the effects of chronic consumption of AOB, db/db mice received the basal diet or a diet containing AOB extract at 0.4% or 0.8%, or acarbose at 0.04% for 7 weeks. Blood glycated hemoglobin and serum glucose and insulin levels were measured. Expression of adiponectin protein in epididymal white adipose tissue was determined by Western blotting.

RESULTS

In vitro inhibitory effect of AOB extract on α-glucosidase was 92% as strong as that of acarbose. The AOB extract (500 mg/kg) or acarbose (50 mg/kg) significantly suppressed the postprandial rise of blood glucose after maltose challenge and the area under the glycemic response curve in normal mice. The AOB extract at 0.4% or 0.8% of diet or acarbose at 0.04% of diet significantly lowered levels of serum glucose and blood glycated hemoglobin and homeostasis model assessment for insulin resistance values in db/db mice. The expression of adiponectin protein in adipose tissue was significantly elevated by the consumption of AOB at 0.8% of diet.

CONCLUSIONS

Autumn olive (E. umbellata Thunb.) berry may reduce postprandial hyperglycemia by inhibiting α-glucosidase in normal mice. Chronic consumption of AOB may alleviate fasting hyperglycemia in db/db mice partly by inhibiting α-glucosidase and upregulating adiponectin expression.