Antibacterial and antioxidant activities of the extract and some flavonoids from aerial parts of Echinops Gracilis O. Hoffm. (Asteraceae)

Mortality due to microbial diseases continues to be a major problem in many developing countries. The present study aims to evaluate the antibacterial and antioxidant activities of the ethyl acetate extract and some isolated compounds from aerial parts of Echinops gracilis. The phytochemical study resulted in the isolation of a new flavonoid derivative named apigenin-7-O-(4″-feruloyl)-β-D-glucoside (1), together with 2 known compounds: apigenin-7-O-(4″-trans-p-hydroxycinnamoyl)-β-D-glucoside (2), and apigenin-7-O-glucoside (3). Their chemical structures were determined using a combination of NMR and IR spectroscopic and MS techniques, as well as by comparison with literature data. The extract and isolates were evaluated for their antibacterial and antioxydant properties. The EtOAc extract and compounds 1 and 2 showed the ability to scavenge 2,2′-zino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS) with scavenging concentration (SC50) values of 13.6 ± 0.8 µg/mL, 108.2 ± 4.3 µg/mL, and 28.5 ± 2.2 µg/mL, respectively. In addition, compound 1 displayed significant activity against Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumonia, with minimum inhibition concentration (MIC) values of 31.2, 15.6, and 31.2 µg/mL respectively.https://journals.sagepub.com/home/npxhj2022Chemistr

Antileishmanial and cytotoxic activities of a new limonoid and a new phenyl alkene from the stem bark of Trichilia gilgiana (Meliaceae)

AbstractOne new limonoid, trigilgianin (1), one new phenyl alkene, epoxy gilgialkene (2), together with five known compounds: scopoletin (3), sitosteryl-6’-O-undecanoate-β-D-glucoside (4), sitosteryl-O-β-D-glucopyranoside (5), cinchonain A (6) and cinchonain B (7) were isolated from the stem bark of Trichilia gilgiana Harms. (Meliaceae). All compounds were isolated for the first time from this species. The structures were elucidated on the basis of spectral studies and by comparison of these data with those from the literature. Compounds 1, 2, 3, 6 and 7 were tested for in vitro antileishmanial activity against visceral leishmaniasis parasite Leishmania donovani and cytotoxicity against macrophage RAW 264.7 cell line. Compounds 1 and 3 showed the highest antileishmanial activity (IC50 values of 6.044 and 6.804 µg/mL, respectively) with low cytotoxicity (CC50 values of >200 and 47.47 µg/mL, respectively), while compound 2 was moderately active on L. donovani promastigotes (IC50 56.81 µg/mL)

SARS-CoV-2 main protease inhibitors from the stem barks of Discoglypremna caloneura (Pax) Prain (Euphorbiaceae) and Pterocarpus erinaceus Poir (Fabaceae) and their molecular docking investigation

Abstract The main viral protease (Mpro) of SARS-CoV-2 provides an excellent target for antivirals, due to its essential and conserved function in the viral replication cycle. We reported in this study, the SARS-CoV-2 main protease inhibitory effect of twelve compounds isolated from D. caloneura and P. erinaceus together with four derivatives. Among the effectively tested samples, two derivatized compounds displayed significant improvement on the activity from the starting material, friedelin (1) through the acetoreduced (2) to the acetoxy product (3) with respective IC50 values of 42.89, 29.69 and 19.39 µg/mL. The latter displayed the highest activity although lower as compared to that of baicalein, the positive control with IC50 0.41 µg/mL. The molecular docking study showed that an increase in the number of hydrogen bonds between compounds and active site of Mpro resulted in increased inhibition. Graphical Abstrac

Antileishmanial and Antiplasmodial Activities of Secondary Metabolites from the Root of Antrocaryon klaineanum Pierre (Anacardiaceae)

International audienceAntrocaryon klaineanum is traditionally used for the treatment of back pain, malaria, female sterility, chlamydiae infections, liver diseases, wounds, and hemorrhoid. This work aimed at investigating the bioactive compounds with antileishmanial and antiplasmodial activities from A. klaineanum. An unreported glucocerebroside antroklaicerebroside (1) together with five known compounds (2–6) were isolated from the root barks of Antrocaryon klaineanum using chromatographic techniques. The NMR, MS, and IR spectroscopic data in association with previous literature were used for the characterization of all the isolated compounds. Compounds 1–4 are reported for the first time from A. klaineanum. The methanol crude extract (AK-MeOH), the n-hexane fraction (AK-Hex), the dichloromethane fraction (AK-DCM), the ethyl acetate fraction (AK-EtOAc), and compounds 1–6 were all evaluated for their antiparasitic effects against Plasmodium falciparum strains susceptible to chloroquine (3D7), resistant to chloroquine (Dd2), and promastigotes of Leishmania donovani (MHOM/SD/62/1S). The AK-Hex, AK-EtOAc, AK-MeOH, and compound 2 were strongly active against Dd2 strain with IC50 ranging from 2.78 ± 0.06 to 9.30 ± 0.29 µg/mL. Particularly, AK-MeOH was the most active—more than the reference drugs used—with an IC50 of 2.78 ± 0.06 µg/mL. The AK-EtOAc as well as all the tested compounds showed strong antileishmanial activities with IC50 ranging from 4.80 ± 0.13 to 9.14 ± 0.96 µg/mL