Inhibitory effects of the ethyl acetate extract from bulbs of Scilla scilloides on lipoxygenase and hyaluronidase activities

LC-QToF chemical profiling of Euphorbia grantii Oliv. and its potential to inhibit LPS-induced lung inflammation in rats via the NF-κB, CY450P2E1, and P38 MAPK14 pathways

Acute lung injury (ALI) is a life-threatening syndrome that causes high morbidity and mortality worldwide. The aerial parts of Euphorbia grantii Oliv. were extracted with methanol to give a total methanolic extract (TME), which was further fractionated into dichloromethane (DCMF) and the remaining mother liquor (MLF) fractions. Biological guided anti-inflammatory assays in vitro revealed that the DCMF showed the highest activity (IC50 6.9 ± 0.2 μg/mL and 0.29 ± 0.01 μg/mL) compared to. celecoxib (IC50 of 88.0 ± 1 μg/mL and 0.30 ± 0.01 μg/mL) on COX-1 and COX-2, respectively. Additionally, anti-LOX activity was IC50 = 24.0 ± 2.5 μg/mL vs. zileuton with IC50 of 40.0 ± 0.5 μg/mL. LC-DAD-QToF analysis of TME and the active DCMF resulted in the tentative identification and characterization of 56 phytochemical compounds, where the diterpenes were the dominated metabolites. An LPS-induced inflammatory model of ALI (10 mg/kg i.p) was used to assess the anti-inflammatory potential of DCMF in vivo at dose of 200 mg/kg and 300 mg/kg compared to dexamethasone (5 mg/kg i.p). Our treatments significantly reduced the pro-inflammatory cytokines (TNF-α, IL-1, IL-6, and MPO), increased the activity of antioxidant enzymes (SOD, CAT, and GSH), decreased the activity of oxidative stress enzyme (MDA), and reduced the expression of inflammatory genes (p38.MAPK14 and CY450P2E1). The western blotting of NF-κB p65 in lung tissues was inhibited after orally administration of the DCMF. Histopathological study of the lung tissues, scoring, and immunohistochemistry of transforming growth factor-beta 1 (TGF-β1) were also assessed. In both dose regimens, DCMF of E. grantii prevented further lung damage and reduced the side effects of LPS on acute lung tissue injury.

Palladium-Catalyzed Skeletal Rearrangement of Substituted 2-Silylaryl Triflates via 1,5-C-Pd/C-Si Bond Exchange

A palladium-catalyzed skeletal rearrangement of 2-(2-allylarylsilyl)aryl triflates has been developed to give highly fused tetrahydrophenanthrosilole derivatives via unprecedented 1,5-C-Pd/C-Si bond exchange. The reaction pathways can be switched toward 4-membered ring-forming C(sp2 )-H alkylation by tuning the reaction conditions to give completely different products, fused dihydrodibenzosilepin derivatives, from the same starting materials. The inspection of the reaction conditions revealed the importance of carboxylates in promoting the C-Pd/C-Si bond exchange.

Spiro-Flavonoids in Nature: A Critical Review of Structural Diversity and Bioactivity

Based on the literature data from 1973 to 2022, this work summarizes reports on spiro-flavonoids with a spiro-carbon at the center of their structure and how this affects their isolation methods, stereochemistry, and biological activity. The review collects 65 unique structures, including spiro-biflavonoids, spiro-triflavonoids, spiro-tetraflavonoids, spiro-flavostilbenoids, and scillascillin-type homoisoflavonoids. Scillascillin-type homoisoflavonoids comprise spiro[bicyclo[4.2.0]octane-7,3'-chromane]-1(6),2,4-trien-4'-one, while the other spiro-flavonoids contain either 2H,2'H-3,3'-spirobi[benzofuran]-2-one or 2'H,3H-2,3'-spirobi[benzofuran]-3-one in the core of their structures. Spiro-flavonoids have been described in more than 40 species of eight families, including Asparagaceae, Cistaceae, Cupressaceae, Fabaceae, Pentaphylacaceae, Pinaceae, Thymelaeaceae, and Vitaceae. The possible biosynthetic pathways for each group of spiro-flavonoids are summarized in detail. Anti-inflammatory and anticancer activities are the most important biological activities of spiro-flavonoids, both in vitro and in vivo. Our work identifies the most promising natural sources, the existing challenges in assigning the stereochemistry of these compounds, and future research perspectives.

Anticholinesterase and anti-inflammatory constituents from Caralluma awdeliana, a medicinal plant from Yemen

From the dichloromethane (DCM) fraction of the crude ethanolic extract of Caralluma awdeliana, four pregnane glycosides and a flavone glycoside were isolated using a bio-guided isolation approach. The different extracts of C. awdeliana were subjected to in vitro enzyme inhibitory assays of anticholinesterases (AChE and BChE) and anti-inflammatory (COXs and 5-LOX). The highest inhibitory activity was exhibited by DCM fraction against COX-1, COX-2, and 5-LOX with IC₅₀ of 4.8 ± 0.5 μg/mL, 0.68 ± 0.2 μg/mL, and 39.5 ± 3.0 μg/mL, respectively. The DCM showed also a moderate activity against AChE (IC₅₀ 384.72 ± 3.6 μg/mL), and BChE (IC₅₀ 384.72 ± 3.6 μg/mL). The repeated chromatography of DCM fraction resulted in the isolation of two new pregnane glycosides, namely awdeliosides A (1) and B (4), two known ones, namely caratuberosides B and D, along with the known flavone glycoside identified as luteolin 4 -O-neohesperidoside. All the isolated compounds were tested for their in vitro enzyme inhibitory assays. Among the isolated compounds, awdelioside B (4) showed the most potent effect against COX-1 with IC₅₀ value of 10.99 ± 0.35 μM, compared to standard celecoxib (IC₅₀ 230.74 ± 2.62 μM). All the isolated compounds showed weak anticholinesterase, except a moderate activity observed for awdelioside B (4) against BChE with IC₅₀ value of 15.63 ± 3.5 μM, compared to standard donepezil (IC₅₀ 0.77 ± 0.0088 μM).

Evaluating the Antioxidants, Whitening and Antiaging Properties of Rice Protein Hydrolysates

Plant-derived protein hydrolysates have potential applications in nutrition. Rice protein hydrolysates (RPHs), an excellent source of proteins, have attracted attention for the development of cosmeceuticals. However, few studies have reported the potential application of RPH in analysis, and this study examined their antioxidant activities and the inhibitory activities of skin aging enzymes. The results indicated that the total phenolic and flavonoid concentrations were 2.06 ± 0.13 mg gallic acid equivalent/g RPHs and 25.96 ± 0.52 µg quercetin equivalent/g RPHs, respectively. RPHs demonstrated dose-dependent activity for scavenging free radicals from 1,1-diphenyl-2-picrylhydrazyl [half-maximal inhibitory concentration (IC50) = 42.58 ± 2.1 mg/g RPHs] and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (IC50 = 2.11 ± 0.88 mg/g RPHs), dose-dependent reduction capacity (6.95 ± 1.40 mg vitamin C equivalent/g RPHs) and oxygen radical absorbance capacity (473 µmol Trolox equivalent/g RPHs). The concentrations of the RPH solution required to achieve 50% inhibition of hyaluronidase and tyrosinase activities were determined to be 8.91 and 107.6 mg/mL, respectively. This study demonstrated that RPHs have antioxidant, antihyaluronidase, and antityrosinase activities for future cosmetic applications.

Chemical Constituents of the Bulbs of Scilla peruviana and Their Pancreatic Lipase Inhibitory Activity

Scilla species are used as medicinal plants and contain lanosterol-type triterpene glycosides. The phytochemical investigation of the bulbs of Scilla peruviana led to the isolation of 17 compounds, including three new rearranged pentacyclic-lanosterol glycosides (1–3) and two new homoisoflavanone glycosides (12 and 13). The structures of the undescribed compounds were determined by extensive spectroscopic analyses, including two-dimensional (2D) NMR. Among the triterpene glycosides, 2, 3, and 6 showed significant pancreatic lipase inhibitory activity in a concentration-dependent manner in vitro. The oral administration of scillascilloside D-2 (6) reduced serum triglyceride levels in a dose-dependent manner in soybean oil-loaded mice.

Effect of phenolic compounds from the leaves of Psidium guajava on the activity of three metabolism-related enzymes

Enzyme activity modulation by synthetic compounds provide strategies combining the inhibitory and therapeutic mode of action of the confirmed inhibitors. However, natural modulators could offer a valuable alternative for synthetic ones for the treatment of different chronic diseases (diabetes, hypertension, cancer); due to the numerous side effects of the latter. In vitro screening assays were conducted for Psidium guajava leaf methanolic extract against three metabolism-related enzymes; α-amylase, tyrosinase, and hyaluronidase. The obtained results showed that the examined extract retained weak and moderate multitarget inhibition against α-amylase, tyrosinase, and hyaluronidase, respectively; however, the leaf fractions exhibited stronger inhibitions for the three investigated enzymes. Fractionation of P. guajava leaf extract revealed that anthraquinones and ellagic acid are of the major active compounds with inhibitory activities for α-amylase, tyrosinase, and hyaluronidase. Kinetic studies showed that quinalizarin inhibition is competitive for both α-amylase and hyaluronidase, and ellagic acid inhibition for tyrosinase and hyaluronidase is competitive and un-competitive, respectively. The molecular docking studies of quinalizarin and ellagic acid with α-amylase, tyrosinase, and hyaluronidase showed high binding energies with different bonds stabilizing the ligand-protein complex. Compiling all obtained results led to conclude that both P. guajava leaf fractions, quinalizarin and ellagic acid, have multitarget activities with potential therapeutic applications in many metabolic disorders.

New Tetrahydroacridine Hybrids with Dichlorobenzoic Acid Moiety Demonstrating Multifunctional Potential for the Treatment of Alzheimer's Disease

A series of new tetrahydroacridine and 3,5-dichlorobenzoic acid hybrids with different spacers were designed, synthesized, and evaluated for their ability to inhibit both cholinesterase enzymes. Compounds 3a, 3b, 3f, and 3g exhibited selective butyrylcholinesterase (EqBuChE) inhibition with IC₅₀ values ranging from 24 to 607 nM. Among them, compound 3b was the most active (IC₅₀ = 24 nM). Additionally, 3c (IC₅₀ for EeAChE = 25 nM and IC₅₀ for EqBuChE = 123 nM) displayed dual cholinesterase inhibitory activity and was the most active compound against acetylcholinesterase (AChE). Active compound 3c was also tested for the ability to inhibit Aβ aggregation. Theoretical physicochemical properties of the compounds were calculated using ACD Labs Percepta and Chemaxon. A Lineweaver–Burk plot and docking study showed that 3c targeted both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE. Moreover, 3c appears to possess neuroprotective activity and could be considered a free-radical scavenger. In addition, 3c did not cause DNA damage and was found to be less toxic than tacrine after oral administration; it also demonstrated little inhibitory activity towards hyaluronidase (HYAL), which may indicate that it possesses anti-inflammatory properties. The screening for new in vivo interactions between 3c and known receptors was realized by yeast three-hybrid technology (Y3H).

Biological assessment of new tetrahydroacridine derivatives with fluorobenzoic moiety in vitro on A549 and HT-29 cell lines and in vivo on animal model

A new series of tetrahydroacridine derivatives with the fluorobenzoyl moiety was synthesized and evaluated for cytotoxic activity against lung cancer cell lines A549 and colorectal cancer HT29. The cytotoxic activity of the compounds was compared on the somatic cell line-EAhy926. Compounds showed high cytotoxic activity on A549 cells (IC₅₀ 183.26-68.07 μM) and HT29 cells (IC₅₀ 68.41-19.70 μM), higher than controls-etoposide (IC₅₀ 451.47 μM) toward A549 and 5-fluorouracil (IC₅₀ 1626.85 μM) against HT29. Derivative 4 was the most cytotoxic to A549, whereas for the cell lines HT29 compound 6. Selected compounds showed similar cytotoxicity to the EAhy926 cell line (IC₅₀ about 50 μM). In the hyaluronidase inhibition assay, all compounds exhibited anti-inflammatory activity, including 4 exhibiting the best inhibitory activity-IC₅₀ of 52.27 μM when the IC₅₀ heparin was 56.41 μM. Mathematical modeling was performed to determine LD₅₀ after intraperitoneal, oral, intravenous and subcutaneous administration and to predict potential mutagenicity and carcinogenicity of the compounds analyzed. Obtained results showed that tested derivatives are slightly toxic compounds, and LD₅₀ values (mg/kg) ranged from 680 to 1200 (oral rat model), the analyzed compounds have low mutagenic potential, and differences between derivatives are insignificant and very low probability of carcinogenicity. To confirm mathematical calculations, an in vivo test was carried out on a laboratory mouse model for two selected compounds. It allowed to qualify compounds: 6 to category 4 of the GHS scale, and 4 to category 3 of the GHS scale.

Novel tetrahydroacridine derivatives with iodobenzoic moieties induce G0/G1 cell cycle arrest and apoptosis in A549 non-small lung cancer and HT-29 colorectal cancer cells

A series of nine tetrahydroacridine derivatives with iodobenzoic moiety were synthesized and evaluated for their cytotoxic activity against cancer cell lines—A549 (human lung adenocarcinoma), HT-29 (human colorectal adenocarcinoma) and somatic cell line—EA.hy926 (human umbilical vein cell line). All compounds displayed high cytotoxicity activity against A549 (IC₅₀ 59.12–14.87 µM) and HT-29 (IC₅₀ 17.32–5.90 µM) cell lines, higher than control agents—etoposide and 5-fluorouracil. Structure–activity relationship showed that the position of iodine in the substituent in the para position and longer linker most strongly enhanced the cytotoxic effect. Among derivatives, 1i turned out to be the most cytotoxic and displayed IC₅₀ values of 14.87 µM against A549 and 5.90 µM against HT-29 cell lines. In hyaluronidase inhibition assay, all compounds presented anti-inflammatory activity, however, slightly lower than reference compound. ADMET prediction showed that almost all compounds had good pharmacokinetic profiles. 1b, 1c and 1f compounds turned out to act against chemoresistance in cisplatin-resistant 253J B-V cells. Compounds intercalated into DNA and inhibited cell cycle in G0/G1 phase—the strongest inhibition was observed for 1i in A549 and 1c in HT-29. Among compounds, the highest apoptotic effect in both cell lines was observed after treatment with 1i. Compounds caused DNA damage and H2AX phosphorylation, which was detected in A549 and HT-29 cells. All research confirmed anticancer properties of novel tetrahydroacridine derivatives and explained a few pathways of their mechanism of cytotoxic action.

Ruthenium-Catalyzed C-H Activation of Salicylaldehyde and Decarboxylative Coupling of Alkynoic Acids for the Selective Synthesis of Homoisoflavonoids and Flavones

Homoisoflavonoids were formed in DMSO exclusively, and flavones were formed in t-AmOH when salicylaldehyde and alkynoic acids reacted with [Ru(p-cymene)Cl₂]₂ and CsOAc. They were formed through C-H activation of salicylaldehyde and decarboxylative coupling of alkynoic acid. This reaction system showed good yields, broad substrate scope, and good functional group tolerance. It was found that chalcone was an intermediate in the formation of both homoisoflavonoid and flavone.

Synthesis of Natural Homoisoflavonoids Having Either 5,7-Dihydroxy-6-methoxy or 7-Hydroxy-5,6-dimethoxy Groups

Naturally occurring homoisoflavonoids containing either 5,7-dihydroxy-6-methoxy or 7-hydroxy-5,6-dimethoxy groups such as the antiangiogenic homoisoflavanone, cremastranone, were synthesized via three or four linear steps from the known 4-chromenone. This facile synthesis includes chemoselective 1,4-reduction of 4-chromenone and selective deprotection of 3-benzylidene-4-chromanone a containing C7-benzyloxy group.