In vitro anticancer activity of loquat tea by inducing apoptosis in human leukemia cells

From by-products to new application opportunities: the enhancement of the leaves deriving from the fruit plants for new potential healthy products

In the last decades, the world population and demand for any kind of product have grown exponentially. The rhythm of production to satisfy the request of the population has become unsustainable and the concept of the linear economy, introduced after the Industrial Revolution, has been replaced by a new economic approach, the circular economy. In this new economic model, the concept of "the end of life" is substituted by the concept of restoration, providing a new life to many industrial wastes. Leaves are a by-product of several agricultural cultivations. In recent years, the scientific interest regarding leaf biochemical composition grew, recording that plant leaves may be considered an alternative source of bioactive substances. Plant leaves' main bioactive compounds are similar to those in fruits, i.e., phenolic acids and esters, flavonols, anthocyanins, and procyanidins. Bioactive compounds can positively influence human health; in fact, it is no coincidence that the leaves were used by our ancestors as a natural remedy for various pathological conditions. Therefore, leaves can be exploited to manufacture many products in food (e.g., being incorporated in food formulations as natural antioxidants, or used to create edible coatings or films for food packaging), cosmetic and pharmaceutical industries (e.g., promising ingredients in anti-aging cosmetics such as oils, serums, dermatological creams, bath gels, and other products). This review focuses on the leaves' main bioactive compounds and their beneficial health effects, indicating their applications until today to enhance them as a harvesting by-product and highlight their possible reuse for new potential healthy products.

Antioxidant and Antiproliferative Activities of Phenolic Extracts of Eriobotrya japonica (Thunb.) Lindl. Fruits and Leaves

Increasing interest in new sources of secondary metabolites as biologically active substances has resulted in an advanced study of many plant species. Loquat (Eriobotrya japonica (Thunb.) Lindl. = Rhaphiolepis bibas (Lour.) Galasso & Banfi, Rosaceae family), an evergreen, subtropical fruit tree, native to China and Japan, but cultivated in southern countries of Europe, is a species commonly used in folk medicine and may be an excellent source of bioactive compounds. Therefore, the aim of the present study was to evaluate the profile of the phenolic constituents of E. japonica fruits and leaves originating from Tuscany (Italy), as well as their in vitro antioxidant and chemopreventive activities on human cancer cell lines breast adenocarcinoma (MCF-7), colon adenocarcinoma (Caco-2 and HT-29), and glioblastoma (U87MG). Results revealed that the extract of leaves displayed higher antioxidant and anticancer potential than the fruit extract and contained 25 individual phenolic compounds that have been characterized and quantified by the UPLC-PDA-MS method. The antiproliferative activity was correlated with the content of polyphenolic compounds indicating that both fruits and leaves are a good source of antioxidants and may be exploited as nutraceuticals enriching food or as components for the cosmetic/pharmaceutical industry.

Traditional uses, phytochemistry, pharmacology, and toxicity of Eriobotrya japonica leaves: A summary

ETHNOPHARMACOLOGICAL RELEVANCE

Eriobotrya japonica Lindl. has been included in "The Plant List" (http://www.theplantlist.org) and is the most widely researched species in its genus. E. japonica is a subtropical evergreen fruit tree belonging to the Rosaceae family. Its dried leaves are widely used in traditional Chinese herbal medicine to treat coughing caused by pulmonary inflammation, dyspnea due to asthma and cough, nausea caused by stomach disorders, restlessness, and thirst. Furthermore, it is used to treat stomach ache, ulcers, chronic bronchitis, cancer, and diabetes mellitus in Japanese folk medicine. However, no systematic reports on E. japonica leaves have been published before.

AIM OF THE STUDY

This review summarizes the available information on the traditional uses, phytochemistry, pharmacology, toxicity, and quality control of various extracts and phytoconstituents of E. japonica leaves.

MATERIALS AND METHODS

Relevant publications between 1931 and 2022 were considered. Chinese and English studies on E. japonica leaves were collected from databases, including PubMed, Web of Science, Elsevier, ACS Publications, Springer, and CNKI (Chinese). The traditional uses, phytochemistry, pharmacology, toxicity, and quality control of E. japonica leaves were reviewed.

RESULTS

Briefly, 164 compounds, including triterpenes, flavonoids, sesquiterpene glycosides, megastigmane derivatives, phenylpropanoids, and organic acids, have been identified from E. japonica leaves, in addition to 169 volatile oils. More than half of these compounds have not yet been reported to have pharmacological activities. Triterpenes and flavonoids are the most important bioactive compounds responsible for pharmacological activities, such as antidiabetic, anti-inflammatory, and antitumor activities. Other beneficial physiological effects such as antioxidant, hepatoprotective, bronchodilatory, antitussive, and expectorant effects and tracheal smooth muscle relaxation, protection against myocardial ischemia injury, and improved cognitive activities have also been reported. High doses of E. japonica leaf extracts have been used in laboratory animals, and no side effects or toxicity-symptoms have been observed.

CONCLUSIONS

The pharmacological activities of E. japonica leaves support their use in traditional Chinese herbal medicine. However, several aspects, such as the bioavailability, pharmacodynamics, pharmacokinetics, mechanism of action, and structure-activity relationships of the pure compounds isolated from E. japonica leaves, have not been studied yet and warrant further studies.

In vitro simulated digestion and fecal fermentation of polysaccharides from loquat leaves: Dynamic changes in physicochemical properties and impacts on human gut microbiota

The aim of this study was to well understand the dynamic changes of physicochemical properties of polysaccharides from loquat leaves (LLP) during in vitro simulated saliva-gastrointestinal digestion and fecal fermentation and its related impacts on human gut microbiota. Results showed that the contents of reducing sugar of LLP slightly increased during the gastrointestinal digestion, and its molecular weight also slightly decreased, suggesting that LLP could be slightly degraded under the gastrointestinal digestion conditions. Moreover, during the fecal fermentation, the molecular weight of the indigestible LLP (LLP-I) significantly decreased, and the molar ratio of constituent monosaccharides of LLP-I, such as glucuronic acid, galacturonic acid, galactose, and arabinose, significantly changed, indicating that LLP-I could be degraded and consumed by human gut microbiota. Indeed, some beneficial bacteria such as Megasphaera, Megamonas, Bifidobacterium, Phascolarctobacterium, and Desulfovibrio significantly increased, suggesting that LLP-I could change the composition and abundance of gut microbiota. LLP-I could also promote the production of health-promoting short chain fatty acids. Results from this study are benefical to well understand the in vitro digestion and fecal fermentation behaviors of LLP, and LLP can be developed as a potential prebiotic in the functional food industry.

Ursolic Acid-Based Derivatives as Potential Anti-Cancer Agents: An Update

Ursolic acid is a pharmacologically active pentacyclic triterpenoid derived from medicinal plants, fruit, and vegetables. The pharmacological activities of ursolic acid have been extensively studied over the past few years and various reports have revealed that ursolic acid has multiple biological activities, which include anti-inflammatory, antioxidant, anti-cancer, etc. In terms of cancer treatment, ursolic acid interacts with a number of molecular targets that play an essential role in many cell signaling pathways. It suppresses transformation, inhibits proliferation, and induces apoptosis of tumor cells. Although ursolic acid has many benefits, its therapeutic applications in clinical medicine are limited by its poor bioavailability and absorption. To overcome such disadvantages, researchers around the globe have designed and developed synthetic ursolic acid derivatives with enhanced therapeutic effects by structurally modifying the parent skeleton of ursolic acid. These structurally modified compounds display enhanced therapeutic effects when compared to ursolic acid. This present review summarizes various synthesized derivatives of ursolic acid with anti-cancer activity which were reported from 2015 to date.

Polysaccharides from loquat (Eriobotrya japonica) leaves: Impacts of extraction methods on their physicochemical characteristics and biological activities

Impacts of hot water extraction (HWE), pressurized water extraction (PWE), high-speed shearing homogenization extraction, microwave assisted extraction (MAE), ultrasound assisted extraction (UAE), ultrasound assisted enzymatic extraction, and ultrasound-microwave assisted extraction (UMAE) on physicochemical characteristics and bioactivities of polysaccharides from loquat (Eriobotrya japonica) leaves (LLPs) were investigated. Results showed that the degrees of esterification, contents of phenolics and uronic acids, constituent monosaccharides, apparent viscosities, and molecular weights of LLPs varied by different extraction methods. Bioactivities of LLPs were also significantly affected by different extraction methods. The high molecular weight and high degree of esterification of LLP-W and LLP-P extracted by HWE and PWE, respectively, might contribute to their strong binding capacities. The strong antioxidant activities and inhibitory effects on α-amylase and α-glucosidase were found in LLP-M and LLP-U extracted by MAE and UAE, respectively, which might be attributed to their contents of uronic acids, contents of total phenolics, and molecular weights. The low molecular weights and viscosities of LLP-U and LLP-UM extracted by UMAE might contribute to their strong prebiotic effects. These findings could provide scientific foundations for selecting appropriate extraction methods to obtain LLPs with desired bioactivities for applications in the pharmaceutical and functional food industries.

Comparison of structural characteristics and bioactivities of polysaccharides from loquat leaves prepared by different drying techniques

In the present study, freeze drying, hot-air drying, vacuum drying, and microwave drying at the microwave powers of 400, 600, and 800 W, respectively, were utilized to dry loquat leaves for evaluating the effects of different drying techniques on the physicochemical structures and bioactivities of polysaccharides extracted from loquat leaves (LLPs). Results demonstrated that the physicochemical structures and bioactivities of LLPs significantly affected by different drying techniques. The degrees of esterification, molar ratios of constituent monosaccharides, contents of uronic acids, apparent viscosities, and molecular weights of LLPs were varied by different drying techniques. Additionally, LLPs, particularly LLP-M4 which extracted from loquat leaves prepared by microwave drying at the power of 400 W, exerted remarkable in vitro binding capacities, strong inhibitory effects on α-amylase and α-glucosidase, and obvious antioxidant activities. Results indicated that the microwave drying could be an efficient drying technique before extraction of bioactive LLPs, and LLPs had great potential applications in the functional food and pharmaceutical industries.

Effects of platycodin D on proliferation, apoptosis and PI3K/Akt signal pathway of human glioma U251 cells

Effects of platycodin D (PD) on the proliferation, apoptosis and PI3K/Akt signaling pathway of human glioma U251 cells were investigated. Glioma U251 cells were treated with PD at final concentrations of 0, 16.3, 40.8, 81.6, 163.2 μM, and inhibition rate, early and late apoptotic rate, apoptotic index, expression of apoptosis-related proteins and phosphorylation of the PI3K/Akt signaling pathway were evaluated. The results showed that compared with the control group, PD could increase the proliferation inhibition rate of U251 cells in a dose- and time -dependent manner; PD could also elevate the early and late apoptotic rate, apoptotic index and the level of pro-apoptotic proteins of glioma U251 cells, such as Bax and cleaved caspase-3, but lower the level of apoptosis inhibitory protein, such as Bcl-2; PD could increase the ratio of G₀/G₁ phase U251 cells, and lower the proportion of Sphase U251 cells and the ratio of G₂/M phase U251 cells; PD could reduce the ratio of p-Akt/Akt. The results indicate that PD can inhibit the proliferation, induce the apoptosis and cause the cell cycle arrest in human glioma U251 cells, which may be related to the inhibition of PD on the activation of PI3K/Akt signaling pathway.