RESUMO
Eight undescribed jatrophane diterpenoids, namely euphomicrophane A-H, together with thirteen known diterpenes were isolated from the whole plant extracts of Euphorbia microcarpa (Prokh.) Krylov. Among them, euphomicrophane C and F were possessed the endo-type core structure that naturally rarely appeared. The structures of the purified undescribed compounds were established by extensive spectroscopic and spectrometric analysis, and the single-crystal X-ray diffraction analysis was used to determine the absolute configuration of euphomicrophane E, elusone A and euphorbesulin G. All the isolates were screened for their reversal abilities on P-glycoprotein-mediated multidrug resistant cancer cell line MCF-7/ADR. Compounds euphomicrophane G-H and 3ß,7ß,8α,9α,15ß-pentaacetoxy-5ß-benzoyloxyjatropha-6(17)-11E-dien-14-one were showed potential chemoreversal effect with reversal fold values 18.67, 17.15, and 16.76 at a concentration of 10.0 µM, being equal to or stronger than the positive drug verapamil (16.68).
RESUMO
Seven new coumarinolignans, walthindicins A-F (1a, 1b, 2-5, 7), along with five known analogs (6, 8-11), were isolated from the roots of Waltheria indica. The structures of the new compounds are determined by detailed nuclear magnetic resonance (NMR), circular dichroism (CD) with extensive computational support, and mass spectroscopic data interpretation. Compounds were tested for their antioxidant activity in Human Cervical Cancer cells (HeLa cells). Compounds 1a and 6 showed higher reactive oxygen species (ROS) inhibitory activity at 20 µg/mL when compared with other natural compound-based antioxidants such as ascorbic acid. Considering the role of ROS in nuclear-factor kappa B (NF-κB) activation, compounds 1a and 6 were evaluated for NF-κB inhibitory activity and showed a concentration-dependent inhibition in Human Embryonic Kidney 293 cells (Luc-HEK-293).