Dihydrochalcone C-glycosides from Averrhoa carambola leaves

Phenylethanoid glycosides from Michelia champaca leaves

Chemical investigation on the leaves of Michelia champaca L. (Magnoliaceae) led to the isolation of five previously undescribed phenylethanoid glycosides (PhGs), 4-O-β-d-glucopyranosyl-acteoside (1), 4‴-O-(6-O-E-caffeoyl)-β-d-glucopyranosyl-acteoside (2), 4‴-O-(6-O-E-caffeoyl)-β-d-glucopyranosyl-isoacteoside (3), 6""-O-E-feruloyl-echinacoside (4), and 6""-O-p-E-coumaroyl-echinacoside (5), together with eighteen known PhGs. Their structures were determined by spectroscopic and chemical methods. All the known PhGs except acteoside (8) were not previously reported in the genus. Twenty-one PhGs exhibited more potent DPPH radical scavenging activity and FRAP than l-ascorbic acid (l-AA), and twenty-two PhGs showed better ABTS radical cation scavenging activity than l-AA. In addition, twelve PhGs displayed more potent cellular reactive oxygen species scavenging activity than curcumin. The results revealed that the leaves of M. champaca are a rich source of phenylethanoid glycosides and antioxidants.

Methodologies for Assessing Pancreatic Lipase Catalytic Activity: A Review

Obesity is a disease of epidemic proportions with a concerning increasing trend. Regarded as one of the main sources of energy, lipids can also represent a big part of an unnecessary intake of calories and be, therefore, directly related to the problem of obesity. Pancreatic lipase is an enzyme that is essential in the absorption and digestion of dietary fats and has been explored as an alternative for the reduction of fat absorption and consequent weigh loss.Literature describes a great variability of methodologies and experimental conditions used in research to evaluate the in vitro inhibitory activity of compounds against pancreatic lipase. However, in an attempt to choose the best approach, it is necessary to know all the reaction conditions and understand how these can affect the enzymatic assay.The objective of this review is to understand and summarize the methodologies and respective experimental conditions that are mainly used to evaluate pancreatic lipase catalytic activity.156 studies were included in this work and a detailed description of the most commonly used UV/Vis spectrophotometric and fluorimetric instrumental techniques are presented, including a discussion regarding the differences found in the parameters used in both techniques, namely enzyme, substrate, buffer solutions, kinetics conditions, temperature and pH.This works shows that both UV/Vis spectrophotometry and fluorimetry are useful instrumental techniques for the evaluation of pancreatic lipase catalytic activity, presenting several advantages and limitations, which make the choice of parameters and experimental conditions a crucial decision to obtain the most reliable results.

Advances in plant-derived C-glycosides: Phytochemistry, bioactivities, and biotechnological production

C-glycosides represent a large group of natural products with a C-C bond between the aglycone and the sugar moiety. They exhibit great structural diversity, wide natural distribution, and significant biological activities. By the end of 2021, at least 754 C-glycosides and their derivatives have been isolated and characterized from plants. Thus far, 66 functional C-glycosyltransferases (CGTs) have been discovered from plants, and provide green and efficient approaches to synthesize C-glycosides. Herein, advances in plant-derived C-glycosides are comprehensively summarized from aspects of structural diversity and identification, bioactivities, and biotechnological production. New strategies to discover novel C-glycosides and CGTs, as well as the applications of biotechnological methods to produce C-glycosides in the future are also discussed.

Anti-Obesity Evaluation of Averrhoa carambola L. Leaves and Assessment of Its Polyphenols as Potential α-Glucosidase Inhibitors

Averrhoa carambola L. is reported for its anti-obese and anti-diabetic activities. The present study aimed to investigate its aqueous methanol leaf extract (CLL) in vivo anti-obese activity along with the isolation and identification of bioactive compounds and their in vitro α-glucosidase inhibition assessment. CLL improved all obesity complications and exhibited significant activity in an obese rat model. Fourteen compounds, including four flavone glycosides (1–4) and ten dihydrochalcone glycosides (5–12), were isolated and identified using spectroscopic techniques. New compounds identified in planta included (1) apigenin 6-C-(2-deoxy-β-D-galactopyranoside)-7-O-β-D-quinovopyranoside, (8) phloretin 3′-C-(2-O-(E)-cinnamoyl-3-O-β-D-fucopyranosyl-4-O-acetyl)-β-D-fucopyranosyl-6′-O-β-D fucopyranosyl-(1/2)-α-L arabinofuranoside, (11a) phloretin3′-C-(2-O-(E)-p-coumaroyl-3-O-β-D-fucosyl-4-O-acetyl)-β-D-fucosyl-6′-O-(2-O-β-D-fucosyl)-α-L-arabinofuranoside, (11b) phloretin3′-C-(2-O-(Z)-p-coumaroyl-3-O-β-D-fucosyl-4-O-acetyl)-β-D-fucosyl-6′-O-(2-O-β-D-fucosyl)-α-L-arabinofuranoside. Carambolaside M (5), carambolaside Ia (6), carambolaside J (7), carambolaside I (9), carambolaside P (10a), carambolaside O (10b), and carambolaside Q (12), which are reported for the first time from A. carambola L. leaves, whereas luteolin 6-C-α-L-rhamnopyranosyl-(1-2)-β-D-fucopyranoside (2), apigenin 6-C-β-D-galactopyranoside (3), and apigenin 6-C-α-L-rhamnopyranosyl-(1-2)-β-L-fucopyranoside (4) are isolated for the first time from Family. Oxalidaceae. In vitro α-glucosidase inhibitory activity revealed the potential efficacy of flavone glycosides, viz., 1, 2, 3, and 4 as antidiabetic agents. In contrast, dihydrochalcone glycosides (5–11) showed weak activity, except for compound 12, which showed relatively strong activity.

A Review of Traditional Uses, Phytochemistry and Pharmacological Properties of Some Vietnamese Wound-Healing Medicinal Plants

Wound healing is a sophisticated process that results in the repair of damaged tissues. Any impairment to this process can lead to non-healing (chronic) wounds. Since these can cause a massive burden on the healthcare system, alternative therapies that promote wound healing should be considered. Therapies of natural origins that are safe and with no adverse side effects are especially promising. Vietnam, a tropical-climate country, has many medicinal plants that possess the potential for healing wounds. This report explores the use of some common plants used in Traditional Vietnamese medicine and their molecular mechanisms.

Traditional Uses, Phytochemical Constituents and Pharmacological Properties of Averrhoa carambola L.: A Review

Averrhoa carambola L. (star fruit) is an edible fruit that is extensively cultivated in southern China, Southeast Asia, India, and northern South America. It has a sweet and juicy taste and is frequently used in fruit salads and fruit platters, as a garnish in cocktail drinks and beverages, or squeezed into juice and served as a beverage. Traditionally, it has been used for treating diabetes and diabetic nephropathy, arthralgia, vomiting, lithangiuria, coughing, hangovers, and chronic paroxysmal headache for thousands of years. Currently, approximately 132 compounds have been isolated from A. carambola. Among them, flavonoids, benzoquinone, and their glycosides have been considered as biologically active substances, which are responsible for various biological activities. Pharmacological studies have revealed that crude extracts or monomeric compounds from A. carambola exhibit multiple bioactivities, such as anti-oxidant, anti-hyperglycemic, anti-obesity, anti-hyperlipidemic, anti-tumor, anti-inflammatory, hepatoprotective, cardioprotective, anti-hypertensive, neuroprotective, and others. Thus, A. carambola is a valuable treatment in Chinese medicine with therapeutic potential for multiple diseases, especially diabetes and diabetes-related diseases. Even though it is a very promising candidate in the development of functional food and the pharmaceutical industry, reports on its bioactivities have only been conducted in vivo and in vitro and there is a gap in research regarding clinical settings and safety. This review therefore provides a comprehensive and systematic overview of current progress on botany, ethnopharmacology, phytochemistry, pharmacology, and toxicity of A. carambola, providing a valuable reference for further developments and applications of A. carambola in the pharmaceutical industry and functional food.

Rapid Structure-Based Annotation and Profiling of Dihydrochalcones in Star Fruit (Averrhoa carambola) Using UHPLC/Q-Orbitrap-MS and Molecular Networking

Dihydrochalcones are a subclass of flavonoids. There has been growing interest in dihydrochalcones for their health benefits and potential to modulate flavor, but their comprehensive profile in diverse plant species is lacking. Star fruit is a tropical fruit rich in dihydrochalcones. In this study, a systematic annotation using UHPLC/Q-Orbitrap-MS and molecular networking was established to rapidly identify dihydrochalcones in 12 star fruit cultivars. A total of 53 dihydrochalcones were characterized within a short retention time including one novel compound (phloretin-3'-C-(2-O-trans-p-coumaroyl)-β-d-fucopyranoside) and 23 compounds identified from the Averrhoa genus for the first time. 3-Hydroxyphloretin was the most abundant dihydrochalcone in star fruit. All the identified dihydrochalcones had a higher abundance in leaves compared to fruits. This is the first report that systematically investigates dihydrochalcones in star fruit of multiple cultivars, and the results could provide a useful reference for the future development and utilization of plant genetic resources.