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Four new aromatic polyketides (1-4) were isolated from Penicillium sp. RO-11, obtained from the sediment of a hydrothermal spring in the southwestern region of Saudi Arabia. The new compounds are penipyranicins A-C (1-3), characterized by a 4-methyl-4H-pyran moiety, a structural motif unprecedented among fungal polyketides, and the naphthopyrone derivative isopyrenulin (4). The structures of the new compounds were elucidated on the basis of data from mass spectrometry, 1D and 2D NMR analysis, and comparison between experimental and time-dependent density functional theory-calculated electronic circular dichroism spectra. A plausible biosynthetic pathway connecting penipyranicins and isopyrenulin is proposed. The isolated compounds were active against Gram-positive and Gram-negative bacteria.

Graphical abstract, Serine proteases are essential metabolic enzymes in the midgut of many pests, including the red palm weevil (RPW), Rhynchophorus ferrugineus Olivier, which has a significant impact economically, environmentally and socially worldwide especially in the middle east. Some methods have been used to manage this pest such as trapping of RPW with pheromones, chemicals, and X-rays. However, these methods are costly, not effective and negatively impact the human. The main objective of this study is to contribute to the discovery of an eco-friendly pesticide to eradicate this infection by using serine protease inhibitors (SPIs) extracted from different parts of plant resources. In this research, both in vitro and in vivo effects of SPIs activity against RPW were examined. The protease inhibitors (PIs) activity was recorded in the crude extract that was isolated from the date’s kernel (DKE), host and Calotropis latex (CLE), non-host. These PIs were partially purified by ammonium sulfate precipitation. The midgut tissue of RPW was extracted and analyzed for protases activity assay. PIs assays were consistent with the increased in the inhibitory activity against the midgut proteases after treatment with a DKE and CLE. The reduction of gut proteases by DKE solution and CLE was 39%, 18%, respectively. Partially purified DKE showed the most prominent inhibition pattern of protease activity of the gut extract. While, latex exhibited acute toxicity, imparting the least LC50 (5.132 mg/mL) against RPW larvae. Taken together, these findings provide evidence for the hypothesis that SPIs activity may play an important role in enhancing the mortality of RPW and relieving the toxicity of insecticide in palm trees.

© 2023 Elsevier Inc.Various impurities found nowadays in water can be detrimental to human health. This work focused on utilizing Fe3O4@MnO2 nanocomposite for cleaning organic contaminants from water, including rhodamine B (RhB) and Escherichia coli (E. coli). Analysis methods such as XRD, UV–vis, TEM, and FTIR were used to describe the nanocomposite. The results showed that the developed nanocomposite has good photocatalytic activity against pollutants in wastewater. The E. coli was destroyed after 90 min, and the RhB photodegradation rate was 75%. Moreover, the Fe3O4@MnO2 efficiency as a catalyst for producing hydrogen as an alternative energy source was tested. According to the calculations, the nanomaterial's turnover frequency, activation energy, enthalpy, and entropy are 1061.3 h−1, 28.93 kJ/mol, 26.38 kJ/mol, and −128.41 J/mol.K, respectively. Four reusability tests were completed, and the average reusability was 78%. The obtained data indicated the excellent potential for the developed Fe3O4@MnO2 nanomaterial to act as an adsorbent, thus representing an alternative to the classical depollution methods. This study showed that nanoparticles have a photocatalytic effect against pathogenic bacteria and RhB azo dye in polluted waters and offer an effective catalytic activity to produce hydrogen as an alternative energy source.

Four new aromatic polyketides (

Plicosepalus is an important genus of the Loranthaceae family, and it is a semiparasitic plant grown in Saudi Arabia, traditionally used as a cure for diabetes and cancer in human and for increasing lactation in cattle. A flavonoid quercetin (P1), (-)-catechin (P2), and a flavane gallate 2S,3R-3,3′,4′,5,7-pentahydroxyflavane-5-O-gallate (P3) were isolated from the methanol extract of the aerial parts of P. curviflorus (PCME). The PCME and the isolated compounds were subjected to pharmacological assays to estimate peroxisome proliferator-activated receptors PPARα and PPARγ agonistic, anti-inflammatory, cytotoxic, and antimicrobial activities. Results proved for the first time the dual PPAR activation effect of the PCME and catechin (P2), in addition to the promising anti-inflammatory activity of the flavonoid quercetin (P1). Interestingly, both PCME and isolated compounds showed potent antioxidant activities while no antimicrobial effect against certain microbial strains had been reported from the extract and the isolated compounds. Based on the pharmacological importance of these compounds, an HPTLC validated method was developed for the simultaneous estimation of these compounds in PCME. It was found to furnish a compact and sharp band of compounds P1, P2, and P3 at Rf = 0.34, 0.47, and 0.65, respectively, using dichloromethane, methanol, and formic acid (90 : 9.5 : 0.5, (v/v/v)) as the mobile phase. Compounds P1, P2, and P3 were found to be 11.06, 10.9, 6.96 μg/mg, respectively, in PCME. The proposed HPTLC method offers a sensitive, precise, and specific analytical tool for the quantification of quercetin, catechin, and flavane gallates in P. curviflorus.

Nepeta deflersiana (Lamiaceae) is a well-known medicinal plant that grows in Saudi Arabia. This plant is used in Saudi and Yemeni folk medicine as an anti-inflammatory, carminative, and antirheumatic agent. In order to prove its use in folk medicine, four different extracts from the aerial parts of the plant: petroleum ether, chloroform, ethyl acetate, and n-butanol extracts were subjected to biological assays to screen PPARα and PPARϒ agnostic, antioxidant, anti-inflammatory, and cytotoxic activities. Ethyl acetate and n-butanol extracts of N. deflersiana NDEE and NDBE, respectively, showed a decrease in oxidative stress and inhibition of both NF-kB and iNOS activities with no cytotoxic effects on four human cancer cell lines. Both active extracts were standardized using two bioactive metabolites which were isolated from the aerial parts of the same plant [8-epi-7-deoxyloganic acid (compound 1) and Ursolic acid (compound 2)] by developing a validated HPTLC method. It was found to provide a sharp and compact band of compound 1 at Rf = 0.07 and Rf = 0.57 for compound 2, using chloroform, methanol, and formic acid (8.9:0.8:0.3, v/v/v) as mobile phase at 550 nm. Compounds 1 and 2 were found in NDEE by 9.59 %, w/w, and 84.63 %, w/w, respectively, and by 11.97 %, w/w, and 21.26 %, w/w, respectively, in NDBE.