Inhibitory activity of Aralia continentalis roots on protein tyrosine phosphatase 1B and rat lens aldose reductase

Evaluation of Phytochemistry and Antidiabetic Potential of an Astragalus Species (Astragalus kurdicus Boiss.)

Astragalus kurdicus Boiss. roots are used in folk medicine for antidiabetic purposes. Different Astragalus plant metabolites have a notable potential for antidiabetic activity through varying mechanisms. Herein, this study is designed to assess the antidiabetic activity of Astragalus kurdicus total (AKM: methanol extract, yield: 14.53 %) and sub-extracts (AKB: n-butanol, AKC: chloroform, AKW: water, AKH: hexane extracts), utilizing a range of diabetes-related in vitro methodologies, and to investigate the chemical composition of the plant. The highest astragaloside and saponin content was seen in AKB extract. Among the measured saponins, the abundance of Astragaloside IV (27.41 μg/mg in AKM) was the highest in high-performance thin-layer chromatography (HPTLC) analysis. Furthermore, flavonoid-rich AKC was found to be mostly responsible for the high antioxidant activity. According to the results of the activity tests, AKW was the most active extract in protein tyrosine phosphatase 1 B (PTP1B), dipeptidyl peptidase IV (DPP4), and α-amylase inhibition tests (percent inhibitions are: 87.17 %, 82.4 %, and 91.49 % respectively, at 1 mg/mL). AKM and AKW demonstrated the highest efficacy in stimulating the growth of prebiotic microorganisms and preventing the formation of advanced glycation end products (AGEs). Thus, for the first time, the antidiabetic activity of A. kurdicus was evaluated from various perspectives.

A Comprehensive Review of Traditional Medicinal Uses, Geographical Distribution, Botanical Characterization, Phytochemistry, and Pharmacology of Aralia continentalis Kitag

Aralia continentalis Kitag. (A. continentalis) holds significant medicinal value among the Aralia genus. It has traditionally been employed in ethnomedicine to address a wide range of conditions, including wind-cold-dampness arthralgia; rheumatic pain in the waist and lower extremities; lumbar muscular strain; injuries resulting from falls, fractures, contusions, and strains; headache; toothache; and abscesses. Modern pharmacological research has validated its therapeutic potential, encompassing anti-inflammatory, analgesic, antioxidant, antimicrobial, insecticidal, hepatoprotective, anti-diabetic, and cytotoxic properties, among other pharmacological effects. To compile comprehensive knowledge on A. continentalis, a rigorous literature search was undertaken utilizing databases like SciFinder, PubMed, and Web of Science. This review seeks to delve into the plant's traditional applications, geographical distribution, botanical characteristics, phytochemistry, and pharmacology. The objective is to lay a foundation and propose novel research directions for exploring the plant's potential applications. Currently, one hundred and fifty-nine compounds have been isolated and identified from A. continentalis, encompassing diterpenoids, steroids, triterpenoids, volatile components, phenolics, vitamins, trace elements, and other compounds. Notably, diterpenoids, steroids, triterpenoids, volatile components, and phenolics have exhibited pronounced pharmacological effects, such as anti-inflammatory, analgesic, antioxidant, hepatoprotective, antidiabetic, and antimicrobial activities. However, despite the extensive research conducted, further studies are imperative to unravel new components and mechanisms of action, necessitating more in-depth investigations. This comprehensive exploration could pave the way for advancing and harnessing the potential of A. continentalis.

Aloe juvenna Brandham & S.Carter as α-Amylase Inhibitor and Hypoglycaemic Agent with Anti-inflammatory Properties for Diabetes Management

Despite Aloe's traditional use, Aloe juvenna Brandham & S.Carter is poorly characterized. Other Aloes are known for their antidiabetic activity. This study describes the antidiabetic potentials and phytoconstituents of the A. juvenna leaves methanolic extract (AJME). Twenty-six phytoconstituents of AJME were described using HPLC/MS-MS. Lupeol and vitexin were isolated using column chromatography. The antidiabetic activity of AJME was investigated using an in vivo high-fat diet/streptozotocin-induced diabetic rat model and in vitro α-glucosidase and α-amylase inhibitory activity assays. AJME demonstrated its α-amylase inhibitory activity (IC50=313±39.9 ppm) with no effect on α-glucosidase. In vivo, AJME dose-dependently improved hyperglycaemia in a high-fat diet/streptozotocin-induced diabetic rat model. Notably, the higher dose (1600 mg/kg) of AJME significantly downregulated serum interleukin-6, tumor necrosis factor-α, and matrix metalloproteinase-1 genes, suggesting its anti-inflammatory effect. These findings indicate AJME's potential as a significant antidiabetic agent through its α-amylase inhibition, hypoglycaemic, and anti-inflammatory properties.

Antichilblain Components in Eggplant Based on Network Pharmacology and Biological Evaluation

Eggplant, the fruit of Solanum melongena L. (Solanaceae), is applied externally to relieve the symptoms of chilblains in the folk in East Asia. However, the mechanisms and biological ingredients are not clear. A network pharmacology approach was used to shed light on the mechanisms of eggplant against chilblains, which illustrated that anti-inflammation and antioxidation are mainly involved in the curative effects. Bioassay-guided assays led to the isolation of 44 ingredients (1-44), including two new natural compounds (1-2) and 42 known compounds. Thirteen compounds (3-15) were first reported from the Solanum genus. The anti-inflammatory and antioxidative effects of all isolates were evaluated, and the results showed that 11 compounds have anti-inflammatory activity and 27 have antioxidant activity. Fatty acids, flavonoids, alkaloids, phenolic acids, saponins, and lignans from eggplant have certain anti-inflammatory and antioxidant effects. These results provide a scientific basis for eggplant to treat chilblains.

Pyrrole-2-carboxaldehydes: Origins and Physiological Activities

Pyrrole-2-carboxaldehyde (Py-2-C) derivatives have been isolated from many natural sources, including fungi, plants (roots, leaves, and seeds), and microorganisms. The well-known diabetes molecular marker, pyrraline, which is produced after sequential reactions in vivo, has a Py-2-C skeleton. Py-2-Cs can be chemically produced by the strong acid-catalyzed condensation of glucose and amino acid derivatives in vitro. These observations indicate the importance of the Py-2-C skeleton in vivo and suggest that molecules containing this skeleton have various biological functions. In this review, we have summarized Py-2-C derivatives based on their origins. We also discuss the structural characteristics, natural sources, and physiological activities of isolated compounds containing the Py-2-C group.

Bioactive substances inhibiting COX-2 and cancer cells isolated from the fibrous roots of Alangium chinense (Lour.) Harms

Alangium chinense has been used as a traditional folk medicine for centuries to treat rheumatism, skin diseases, and diabetes by the people of Southeast Asia. However, the bioactive constituents inhibiting COX-2 and cancer cells (HepG2, Caco-2, HeLa) remain unclear. In this study one new (14) along with twenty-four known compounds (1-13, 15-25) were isolated from the fibrous roots of Alangium chinense by chromatographic methods, and identified by NMR, and Gaussian and CD calculation. Compounds 1, 2, 13, 16, 17, 19, 20, 23, and 24 were isolated from this plant for the first time. Their inhibition effects on COX-2 enzyme and cancer cells were evaluated by MTT assay. Compounds 1-4, 13-14, and 16-18 can be used as good inhibitors against COX-2 enzyme, and compounds 1, 13, 14, and 17 were stronger than the positive control (celecoxib). In addition, molecular docking suggested that compounds 13, 17, and 18 belong to ellagic acids and have good inhibition against COX-2 enzyme. While compounds 1, 5, 13 and 21 showed cytotoxicity against HepG2 cells, compounds 2 and 21 showed cytotoxicity against Caco-2 cells, and compound 20 showed cytotoxicity against HeLa cells.

Identification of the antibacterial action mechanism of diterpenoids through transcriptome profiling

Effective antibacterial substances of Aralia continentalis have anti-biofilm and bactericidal activity to the oral pathogen Streptococcus mutans. In this study, three compounds extracted from A. continentalis were identified as acanthoic acid, continentalic acid, and kaurenoic acid by NMR and were further investigated how these diterpenoids affect the physiology of the S. mutans. When S. mutans was exposed to individual or mixed fraction of diterpenoids, severe growth defects and unique morphology were observed. The proportion of unsaturated fatty acids in the cell membrane was increased compared to that of saturated fatty acids in the presence of diterpenoids. Genome-wide gene expression profiles with RNA-seq were compared to reveal the mode of action of diterpenoids. Streptococcus mutans commonly enhanced the expression of 176 genes in the presence of the individual diterpenoids, whereas the expression of 232 genes was considerably reduced. The diterpenoid treatment modulated the expression of genes or operon(s) involved in cell membrane synthesis, cell division, and carbohydrate metabolism of S. mutans. Collectively, these findings provide novel insights into the antibacterial effect of diterpenoids to control S. mutans infection, which causes human dental caries.

Potential of Diterpenes as Antidiabetic Agents: Evidence from Clinical and Pre-Clinical Studies

Diterpenes are a diverse group of structurally complex natural products with a wide spectrum of biological activities, including antidiabetic potential. In the last 25 years, numerous diterpenes have been investigated for antidiabetic activity, with some of them reaching the stage of clinical trials. However, these studies have not been comprehensively reviewed in any previous publication. Herein, we critically discussed the literature on the potential of diterpenes as antidiabetic agents, published from 1995 to September, 2021. In the period under review, 427 diterpenes were reported to have varying degrees of antidiabetic activity. Steviol glycosides, stevioside (1) and rebaudioside A (2), were the most investigated diterpenes with promising antidiabetic property using in vitro and in vivo models, as well as human subjects. All the tested pimaranes consistently showed good activity in preclinical evaluations against diabetes. Inhibitions of α-glucosidase and protein tyrosine phosphatase 1B (PTP 1B) activities and peroxisome proliferator-activated receptors gamma (PPAR-γ) agonistic property, were the most frequently used assays for studying the antidiabetic activity of diterpenes. The molecular mechanisms of action of the diterpenes include increased GLUT4 translocation, and activation of phosphoinositide 3-kinase (PI3K) and AMP-activated protein kinase (AMPK)-dependent signaling pathways. Our data revealed that diterpenes hold promising antidiabetic potential. Stevioside (1) and rebaudioside A (2) are the only diterpenes that were advanced to the clinical trial stage of the drug discovery pipeline. Diterpenes belonging to the abietane, labdane, pimarane and kaurane class have shown promising activity in in vitro and in vivo models of diabetes and should be further investigated.

Ethnobotany and the Role of Plant Natural Products in Antibiotic Drug Discovery

The crisis of antibiotic resistance necessitates creative and innovative approaches, from chemical identification and analysis to the assessment of bioactivity. Plant natural products (NPs) represent a promising source of antibacterial lead compounds that could help fill the drug discovery pipeline in response to the growing antibiotic resistance crisis. The major strength of plant NPs lies in their rich and unique chemodiversity, their worldwide distribution and ease of access, their various antibacterial modes of action, and the proven clinical effectiveness of plant extracts from which they are isolated. While many studies have tried to summarize NPs with antibacterial activities, a comprehensive review with rigorous selection criteria has never been performed. In this work, the literature from 2012 to 2019 was systematically reviewed to highlight plant-derived compounds with antibacterial activity by focusing on their growth inhibitory activity. A total of 459 compounds are included in this Review, of which 50.8% are phenolic derivatives, 26.6% are terpenoids, 5.7% are alkaloids, and 17% are classified as other metabolites. A selection of 183 compounds is further discussed regarding their antibacterial activity, biosynthesis, structure-activity relationship, mechanism of action, and potential as antibiotics. Emerging trends in the field of antibacterial drug discovery from plants are also discussed. This Review brings to the forefront key findings on the antibacterial potential of plant NPs for consideration in future antibiotic discovery and development efforts.

19-nor-pimaranes from Icacina trichantha

Four new unusual 19-nor-pimarane-type diterpenes were isolated from the tuber of Icacina trichantha (Icacinaceae, Oliv.). The structures were elucidated based on spectroscopic and HRMS analysis. The absolute configurations were determined by electronic circular dichroism. All four compounds are structural analogues of icacinol and humirianthol, but do not demonstrate the same cytotoxic activity. A plausible biogenetic pathway is proposed.

A New Alkaloid from the Aerial Parts of Bupleurum chinense DC

A new isoalloxazine alkaloid, named bupleurine A (1), along with five known compounds (2-6), were isolated from the aerial parts of Bupleurum chinense DC. The structure elucidation of the new alkaloid (1) was employed by combining NMR and HR-MS data with comparison of reference in the literature. Five known compounds (2-6) were isolated from Bupleurum genus for the first time. Additionally, their antiproliferative activities on HeLa cells were evaluated by MTT assay and IC₅₀ of compounds 1 and 4-6 were below 10 μm after treatment for 24 h.

2-Formylpyrrole natural products: origin, structural diversity, bioactivity and synthesis

2-Formylpyrroles constitute a large and growing family of bioactive Maillard reaction products found in food, traditional medicine and throughout nature.

A new nucleoside and two new pyrrole alkaloid derivatives from Cordyceps militaris

A new nucleoside, a new natural product nucleoside, and two new pyrrole alkaloids derivatives with eight known compounds were isolated from the fruiting body of Cordyceps militaris. The structures of the new compounds were elucidated through extensive analysis of spectroscopic data including 1D and 2D NMR, HRESIMS, IR and UV. All the isolated compounds were detected for their bioactivities against LPS-induced NO production in RAW 264.7 cells. Unfortunately, all the isolates have shown no obvious activity.

Cataract Preventive Role of Isolated Phytoconstituents: Findings from a Decade of Research

Cataract is an eye disease with clouding of the eye lens leading to disrupted vision, which often develops slowly and causes blurriness of the eyesight. Although the restoration of the vision in people with cataract is conducted through surgery, the costs and risks remain an issue. Botanical drugs have been evaluated for their potential efficacies in reducing cataract formation decades ago and major active phytoconstituents were isolated from the plant extracts. The aim of this review is to find effective phytoconstituents in cataract treatments in vitro, ex vivo, and in vivo. A literature search was synthesized from the databases of Pubmed, Science Direct, Google Scholar, Web of Science, and Scopus using different combinations of keywords. Selection of all manuscripts were based on inclusion and exclusion criteria together with analysis of publication year, plant species, isolated phytoconstituents, and evaluated cataract activities. Scientists have focused their attention not only for anti-cataract activity in vitro, but also in ex vivo and in vivo from the review of active phytoconstituents in medicinal plants. In our present review, we identified 58 active phytoconstituents with strong anti-cataract effects at in vitro and ex vivo with lack of in vivo studies. Considering the benefits of anti-cataract activities require critical evaluation, more in vivo and clinical trials need to be conducted to increase our understanding on the possible mechanisms of action and the therapeutic effects.

Protein tyrosine phosphatase 1B inhibitors from natural sources

Since PTP1B enzyme was discovered in 1988, it has captured the research community's attention. This landmark discovery has stimulated numerous research studies on a variety of human diseases, including cancer, inflammation, and diabetes. Tremendous progress has been made in finding PTP1B inhibitors and exploring PTP1B regulatory mechanisms. This review investigates for the natural PTP1B inhibitors, and focuses on the common characteristics of the discovered structures and structure-activity relationships. To facilitate understanding, all the natural compounds are here divided into five different classes (fatty acids, phenolics, terpenoids, steroids, and alkaloids), according to their skeletons. These PTP1B inhibitors of scaffold structures could serve as a theoretical basis for new concept drug discovery and design.

Diterpenoids from the shed trunk barks of the endangered plant Pinus dabeshanensis and their PTP1B inhibitory effects

11 new (including an unprecedented skeleton, 3) and 28 related known diterpenoids with interesting PTP1B inhibitory effects were identified.

Natural and semisynthetic protein tyrosine phosphatase 1B (PTP1B) inhibitors as anti-diabetic agents

Natural products offered more opportunities to develop new drugs and leading compounds as potent PTP1B inhibitors for treating T2DM.