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Bioactive flavonoid epicatechin has been reported in the peel of litchi fruit but isolated from its hydroalcoholic extracts. This study isolated epicatechin with cellular glucose uptake modulatory and ROS production inhibitory properties from the ethyl acetate (EtOAc) extract using a bioassay-guided approach. The fruit peel was defatted with hexane and sequentially extracted using dichloromethane (DCM), EtOAc, methanol (MeOH) and water. In vitro phytochemical models, namely antioxidant (Fe 3+ reducing, radical scavenging and anti-linoleic acid peroxidative) and glycaemic control (α-glucosidase and α-amylase inhibitory and glucose uptake modulatory), were employed for the bioassay-guided isolation, while the isolated compound was characterised using NMR and mass spectrometry and assessed for dose-dependent inhibition of α-glucosidase and lipopolysaccharide (LPS)-induced cellular ROS production, as well as modulation of cellular glucose uptake. Relative to the other extracts, the EtOAc extract had appreciable phenol and flavonoid contents, which perhaps influenced its potent anti-lipid peroxidative (65.0%) and α-glucosidase inhibitory (52.4%) effects. The α-glucosidase inhibitory potency of the fractions (1-8) from the EtOAc extracts correlated with their flavonoid contents, with fraction 5 outperforming other fractions. The fraction comprised a pool of fractions obtained from the DCM:MeOH:water (7:3:0.281 v / v / v ) solvent system. LC-MS revealed the predominant presence of epicatechin in fraction 5, which was later isolated from one of the sub-fractions (sub-fraction 4) of fraction 5. This sub-fraction had stronger anti-lipid peroxidative (65.5%), α-glucosidase inhibitory (65.8%) and glucose uptake modulatory (38.2%) effects than the other sub-fractions from fraction 5, which could have been influenced by the isolated epicatechin. Moreover, the isolated epicatechin inhibited α-glucosidase (IC 50 = 35.3 µM), modulated cellular glucose uptake (EC 50 = 78.5 µM) and inhibited LPS-induced ROS production in RAW 264.7 macrophages in a dose-dependent fashion [IC 50 = 18.9 µM; statistically comparable ( p > 0.05) to ascorbic acid, IC 50 = 9.57 µM]. Epicatechin from litchi peel EtOAc extract could potentiate glucose uptake modulatory, α-glucosidase inhibitory and ROS suppressive capacities, which could be influential in the use of litchi fruit peel for managing diabetes and associated oxidative damage.

Phytochemical investigation of the EtOAc soluble fraction from leaves of Trichilia dregeana Sond. (Meliaceae) afforded naturally rare four new pentacyclic triterpenoids (1-4), together with five known pentacyclic analogs (5-8, and 11) and two steroids (9 and 10). Their structures were elucidated by extensive spectroscopic techniques such as 1D and 2D NMR and HRESIMS data analyses. The absolute configuration of 1 was determined by using the single-crystal X-ray diffraction analysis. The nitric oxide (NO) production inhibitory assay indicated that the EtOAc fraction as well as 4 and 7 inhibited the NO production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells with the IC 50 values of 83.53 μg/mL and 81.31 and 85.71 μM, respectively. Compounds 1-4 are rare 19(10 → 9)abeo-euphane-type triterpenoids bearing a 3,10-ether bridge. To the best of our knowledge, this study is the first isolation of triterpenoids with the 3,10-ether bridge in their skeleton from the genus Trichilia, providing new insights into the chemodiversity of the terpenoids in T. dregeana., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Oxidative stress is pivotal in the pathology of many diseases. This study investigated the antioxidant phytochemistry of avocado ( Persea americana Mill.) peel. Different solvent extracts (dichloromethane, ethyl acetate, methanol, and water) of avocado peel were subjected to total phenol and flavonoid quantification, as well as in vitro radical scavenging and ferric reducing evaluation. The methanol extract was subjected to gradient column chromatographic fractionation. Fraction 8 (eluted with hexane:chloroform:methanol volume ratio of 3:6.5:0.5, respectively) was subjected to LC-MS analysis. It was assessed for cellular inhibition of lipid peroxidation and lipopolysaccharide (LPS)-induced ROS and NO production. The DPPH radical scavenging mechanism of chlorogenic acid was investigated using Density Functional Theory (DFT). The methanol extract and fraction 8 had the highest phenol content and radical scavenging activity. Chlorogenic acid (103.5 mg/mL) and 1- O -caffeoylquinic acid (102.3 mg/mL) were the most abundant phenolics in the fraction. Fraction 8 and chlorogenic acid dose-dependently inhibited in vitro (IC 50 = 5.73 and 6.17 µg/mL) and cellular (IC 50 = 15.9 and 9.34 µg/mL) FeSO 4 -induced lipid peroxidation, as well as LPS-induced ROS (IC 50 = 39.6 and 28.2 µg/mL) and NO (IC 50 = 63.5 and 107 µg/mL) production, while modulating antioxidant enzyme activity. The fraction and chlorogenic acid were not cytotoxic. DFT analysis suggest that an electron transfer, followed by proton transfer at carbons 3'OH and 4'OH positions may be the radical scavenging mechanism of chlorogenic acid. Considering this study is bioassay-guided, it is logical to conclude that chlorogenic acid strongly influences the antioxidant capacity of avocado fruit peel.

According to a survey, the medicinal use of Androstachys johnsonii Prain is kept secret by traditional healers. Considering that inflammation and oxidative stress are major risk factors for the progression of various chronic diseases and disorders, we resolved to investigate the antioxidant and anti-inflammatory potentials of A. johnsonii using in vitro and cell-based assays. The antioxidant activity of A. johnsonii hydroethanolic leaf extract (AJHLE) was evaluated using the ABTS, DPPH, and FRAP assays. Its cytotoxic effect was assessed on RAW 264.7 macrophages using an MTT assay. Then, its anti-inflammatory effect was evaluated by measuring the NO production and 15-LOX inhibitory activities. Moreover, its preventive effect on ROS production and its regulatory effect on the expression of pro-inflammatory mediators such as IL-1β, IL-10, TNF-α, and COX-2 were determined using established methods. AJHLE strongly inhibited radicals such as ABTS •+ , DPPH • , and Fe 3+ -TPTZ with IC 50 values of 9.07 µg/mL, 8.53 µg/mL, and 79.09 µg/mL, respectively. Additionally, AJHLE induced a significant ( p < 0.05) cytotoxic effect at 100 µg/mL, and when tested at non-cytotoxic concentrations, it inhibited NO and ROS production in LPS-stimulated RAW 264.7 macrophages in a concentration-dependent manner. Furthermore, AJHLE showed that its anti-inflammatory action occurs via the inhibition of 15-LOX activity, the downregulation of COX-2, TNF-α, and IL-1β expression, and the upregulation of IL-10 expression. Finally, chemical investigation showed that AJHLE contains significant amounts of procyanidin, epicatechin, rutin, and syringic acid which support its antioxidant and anti-inflammatory activities. These findings suggest that A. johnsonii is a potential source of therapeutic agents against oxidative stress and inflammatory-related diseases.

In the search of cytotoxic dihydrochalcones, this investigation led to the isolation of seven compounds ( 1 - 7 ) from Eriosema glomeratum and the preparation of eight derivatives ( 8 - 15 ). The cytotoxicity of samples was evaluated against lung (A549), breast (MCF-7), and cervical (HeLa) human cancer cells. The CH 2 Cl 2 /MeOH extract of the aerial part had strong cytotoxicity against all cells [IC 50 11.2 (MCF-7), 8.4 (HeLa) and 13.1 (A549) μg/mL]. A strong activity was also displayed by the n -hexane fraction on MCF-7 (IC 50 11.2 μg/mL). The precursor 3 and the derivative 8 were specifically found as strong cytotoxic agents toward MCF-7 (7.6 μM) and HeLa (3.1 μM), respectively and were more effective than the positive control. Derivatives 8 (3.1 μM) and 9 (21.3 μM) against HeLa were most potent than their precursor 3 (23.7 μM). This is the first preparation of 8 - 14 as well as the cytotoxicity of 3 , 4 , 8 - 15 , fractions, and extract.

A new fructofuranoside glycerol, dryoptkirbioside (1), along with thirteen known compounds (2-14), was isolated from the MeOH extract of Dryopteris kirbi rhizomes by silica gel column chromatography, Sephadex LH-20 column chromatography, and semipreparative HPLC. The structure of the new compound was determined by analyses of its spectroscopic data including nuclear magnetic resonance (NMR), and high-resolution electrospray ionisation mass spectrometry (HR-ESI-MS) and chemical conversions. The hexane-soluble portion and the EAF A fraction showed strong activities against lung (A549), breast (MCF-7), and cervical (HeLa) human cancer cell lines (IC 50 values ranging from 4.0 to 8.8 μg/mL). Aspidinol P (5) and aspidinol B (6) exhibited moderate to low cytotoxicity on the three cell lines (IC 50 values ranging from 20.4 to 58.7 μM). The MeOH extract and hexane-soluble portion had excellent activities against Staphylococcus aureus and Bacillus subtilis (MICs 11.7 and 23.4 μg/mL), whereas the AcOEt- and BuOH-soluble portions were significantly active on S. aureus (MICs 46.9 and 93.8 μg/mL). The main fractions EAF B , EAF C and nBF B displayed excellent activity against S. aureus (MICs 11.7 and 23.4 μg/mL). Aspidinol B (6) had significant activity, while aspidinol P (5) was moderately active against S. aureus and B. subtilis (MICs 42.0 and 89.5 μM)., (© 2023 Wiley-VHCA AG, Zurich, Switzerland.)