Rat intestinal sucrase inhibition of constituents from the roots of Rosa rugosa Thunb

Di- and Triterpenoids from the Rhizomes of Isodon amethystoides and Their Anti-inflammatory Activities

Amethystoidesic acid (1), a triterpenoid with an unprecedented 5/6/6/6 tetracyclic skeleton, and six undescribed diterpenoids, amethystoidins A-F (2-7), were isolated from the rhizomes of Isodon amethystoides along with 31 known di- and triterpenoids (8-38). Their structures were fully elucidated via extensive spectroscopic analysis including 1D and 2D NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and electronic circular dichroism (ECD) calculations. Compound 1 is the first example of a triterpenoid possessing a rare ring system (5/6/6/6) derived from a contracted A-ring and the 18,19-seco-E-ring of ursolic acid. Compounds 6, 16, 21, 22, 24, and 27 significantly inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells, which could be partly mediated by the downregulation of LPS-induced inducible nitric oxide synthase (iNOS) protein expression.

UPLC-ESI-QTOF-MS Profiling of Phenolic Compounds from Eriocephalus africanus: In Vitro Antioxidant, Antidiabetic, and Anti-Inflammatory Potentials

The present study investigated phenolic compounds, antioxidant, antidiabetic, and the anti-inflammatory potentials of methanolic and chloroform extracts of Eriocephalus africanus. The methanolic extract included, polyphenols (112 ± 2.81 mg gallic acid equivalent (GAE)/g), flavonols (76.12 ± 7.95 mg quercetin equivalents (QE)/g); antioxidant capacity (Ferric Reducing Antioxidant Power (FRAP) (752.64 ± 89.0 μmol of ascorbic acid equivalents (AAE) per g dry weight (µmol AAE/g), 2,2-dyphenyl-1-picrylhydrazyl (DPPH) (812.18 ± 51.12 Trolox equivalents per gram of dry mass of plant extracts (μmol TE/g), TEAC (631.63 ± 17.42 µmol TE/g)), while the chloroform extract included polyphenols (39.93 ± 1.36 mg GAE/g), flavonols (44.81 ± 3.74 mg QE/g); antioxidant capacity, DPPH (58.70 ± 5.18 µmol TE/g), TEAC (118.63 ± 3.74 µmol TE/g) and FRAP (107.10 ± 2.41 µmol AAE/g). The phytochemicals profiling performed by UPLC-ESI-QTOF-MS revealed some important polyphenols, predominantly flavonoids, that could be responsible for the antioxidant capacity and biological effects. Both extracts demonstrated a dose-dependent manner of the alpha-glucosidase inhibition with an IC₅₀ between 125 and 250 μg/mL for methanolic extract, while the chloroform extract was at 250 μg/mL. In the L6 myoblasts and C3A hepatocytes, the methanolic extract slightly increased the utilization of glucose, and both extracts exhibited a dose-dependent increase in the glucose uptake in both cell types without significantly increasing the cytotoxicity. Furthermore, both extracts exhibited an anti-inflammatory potential and the findings from the present study could serve as a baseline for further research in the development of pharmaceutical agents.

Paeonone A, a novel nonanortriterpenoid from the roots of Paeonia lactiflora

Paeonone A (1), a unique nonanortriterpenoid, and a new octanortriterpenoid, paeonone B (2), were isolated from the roots of Paeonia lactiflora, together with a known analogue, palbinone (3). Paeonone A (1) is the first example of naturally occurring nonanortriterpenoid with a diketo acid group. Extensive NMR and HRESIMS experiments were applied to identify the structures of 1 and 2, and their absolute configurations were solved by single-crystal X-ray diffraction and ECD data. Biological properties of 1-3 were explored against pancreatic lipase and cancer cell lines.

Pentacylic triterpenes from Lavandula coronopifolia: structure related inhibitory activity on α-glucosidase

Ten pentacyclic triterpenes (1-10) were isolated from Lavandula coronopifolia. We evaluated their α-glucosidase inhibitory activity, and found that the aglycones, 1, 2, 3, 4, 7 and 10 showed superior IC₅₀ values to the positive control. In order to explain the structural requirements for α-glucosidase inhibitory activity, eleven derivatives were prepared, including one new compound, 2-formyl-(A)1-19α-hydroxy-1-norursane-2, 12-dien-28-oic acid 10c. The results demonstrated that a free hydroxyl at ring-A and a free carboxylic group at position 28 are key structural features for the α-glucosidase inhibitory activity, also that an ursane skeleton is optimum for the activity. Additionally, enzyme kinetic analysis of pomolic acid 2, the most potent compound, revealed that it inhibited α-glucosidase in a mixed-type manner. The molecular docking simulation validated this type of inhibition and highlighted the role of the C-3 hydroxyl and C-28 carboxylic groups in interaction with the enzyme in silico.

Triterpenoids

Covering 2014. Previous review: Nat. Prod. Rep., 2017, 34, 90-122 This review covers the isolation and structure determination of triterpenoids reported during 2014 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 374 references are cited.

Determination of the volatile and polyphenol constituents and the antimicrobial, antioxidant, and tyrosinase inhibitory activities of the bioactive compounds from the by-product of Rosa rugosa Thunb. var. plena Regal tea

Background

The phytochemical constituents and biological activities of Rosa rugosa Thunb. var. plena Regal flower cell sap (RFCS) were investigated.

Methods

Volatile constituent, such as linalool, phenylethyl alcohol, citronellol, α-bisabolol, were identified by GC-MS. The contents of hyperoside, kaempferol-3-O-rutinosid, rutin, and luteolin as well as the total flavonoid content in RFCS were determined by HPLC and HPLC-MS. The total polyphenol content was evaluated by the Folin-Ciocalteu colorimetric method. The antioxidant activities of RFCS and the standards were evaluated by DPPH and ABTS radical scavenging assays. The tyrosinase inhibitory activities of the rose samples and standard substance were determined by a spectrophotometric method. The antimicrobial effects of RFCS were evaluated in terms of minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) or minimum Fungicidal concentrations (MFCs).

Results

The rose fraction exhibited a high content of biologically active ingredients. The total content of volatile compounds in RFCS was approximately 48.21 ± 2.76 ng/mL. The total phenolic acid content and total flavonoid content were 0.31 ± 0.01 mg/mL and 0.43 ± 0.01 mg/mL, respectively. Its IC₅₀ value in the DPPH assay was 1120 ± 42 μg/mL, and its IC₅₀ value for ABTS radical scavenging activity was 1430 ± 42 μg/mL.RFCS strongly inhibited L-tyrosine oxidation with an IC₅₀ value of 570 ± 21 μg/mL. Every compound identified in RFCS exhibited broad-spectrum antimicrobial activity. F. nucleatum was most susceptible to RFCS with an MIC of 64 μg/mL and MBC of 250 μg/mL.

Conclusions

Due to its rose-like aroma, phenylethyl alcohol may be combined with linalool for use as a natural skin-whitening agent and skin care additive in the and pharmaceutical industries.

Synthesis of cytotoxically active derivatives based on alkylated 2,3-seco-triterpenoids

Extremely low content of biologically active triterpenoids with the fragmented or contracted ring A extractable from plants is the main disadvantage of their use in drug discovery and practical pharmacology. Development of new methods for synthesis of these compounds and their structural analogs from bioavailable triterpene precursors gives an opportunity to obtain promising agents for pharmacology with excellent yields. A new approach to synthesis of alkylated A-seco-triterpenoids, including the Beckmann fragmentation of 3-methyl-substituted allobetulin or betulinic acid methyl ester with 2-hydroxyimino group in the ring A was proposed. These compounds were used to prepare a series of 2,3-seco- and five-membered ring A lupane and oleanane derivatives, cytotoxicity of which was screened in vitro against the cancer (HEp-2, HCT 116, A549, RD TE32, MS) and non-cancerous (HEK 293) cell lines. Methyl 3-bromomethyl-1-cyano-3-oxo-2,3-seco-2-norlup-20(29)-en-30-al-28-oate was selected as the most active compound (IC₅₀ 3.4-10.4 μM for HEp-2, HCT 116, RD TE32, MS cells) capable of triggering caspase-8-mediated apoptosis in HCT 116 cells accompanied by typical apoptotic chromatin condensation, without any loss of mitochondrial membrane permeability.

Lanostane Triterpenes from the Tibetan Medicinal Mushroom Ganoderma leucocontextum and Their Inhibitory Effects on HMG-CoA Reductase and α-Glucosidase

Sixteen new lanostane triterpenes, ganoleucoins A-P (1-16), together with 10 known tripterpenes (17-26), were isolated from the cultivated fruiting bodies of Ganoderma leucocontextum, a new member of the Ganoderma lucidum complex. The structures of the new compounds were elucidated by extensive spectroscopic analysis and chemical transformation. The inhibitory effects of 1-26 on HMG-CoA reductase and α-glucosidase were tested in vitro. Compounds 1, 3, 6, 10-14, 17, 18, 23, 25, and 26 showed much stronger inhibitory activity against HMG-CoA reductase than the positive control atorvastatin. Compounds 13, 14, and 16 presented potent inhibitory activity against α-glucosidase from yeast with IC₅₀ values of 13.6, 2.5, and 5.9 μM, respectively. In addition, the cytotoxicity of 1-26 was evaluated against the K562 and PC-3 cell lines by the MTT assay. Compounds 1, 2, 6, 7, 10, 12, 16, 18, and 25 exhibited cytotoxicity against K562 cells with IC₅₀ values in the range 10-20 μM. Paclitaxel was used as the positive control with an IC₅₀ value of 0.9 μM. This is the first report of secondary metabolites from this medicinal mushroom.