Antioxidant, hepatoprotective and cytotoxic effects of icetexanes isolated from stem-bark of Premna tomentosa.

The study investigates the antioxidant, hepatoprotective and antiproliferative effects of novel icetexane diterpenoids (ice 1-4) isolated from hexane extract of stem bark of Premna tomentosa. A549, HT-29, MCF-7, MDA-MB-231, A431 cells were used to assess the antiproliferative activity by MTT assay. Cell death induced by apoptosis was determined by morphological assessment studies using acridine orange/ethidium bromide staining (dual staining), mitochondrial potential measurement by JC-1 staining, and cell cycle analysis by propidium iodide staining method by Muse cell analyser. Anti oxidant activity was investigated by in vitro assays such as DPPH, nitric oxide and superoxide scavenging activities. Hepatoprotective activity was determined in vitro with HepG2 cells and in vivo by tBHP induced hepatic damage mice model. Based on the in vitro cytotoxic assays and morphological assessment studies using fluorescence microscopic study (acridine orange and ethidium bromide double staining) and mitochondrial potential measurements, it was found that ice 2 and 3 possess good antiproliferative effect via mitochondrial mediated apoptosis in human lung and breast cancer cells. Results of in vitro antioxidant studies demonstrated that ice-4 has showed good antioxidant activity. The restoration of serum levels of SGOT, SGPT and ALKP, liver GSH status and reduction or inhibition of lipid peroxidation in liver of tBHP intoxicated mice after administration of ice-4 at dose of 250mg/kg indicated its potential use for hepatoprotective activity.

New icetexane diterpenes with intestinal α-glucosidase inhibitory and free-radical scavenging activity isolated from Premna tomentosa roots.

New icetexane diterpenes (1-2); 8, 11, 13-icetexatriene-10-hydroxy, 11, 12, 16-tri acetoxyl (1) and 8, 11, 13-icetexatriene-7, 10, 11-dihydroxy-12, 13-dihydrofuran (2) along with six known compounds namely acetoxy syranzaldehyde (3), syranzaldehyde (4), coniferaldehyde (5), lupeol (6), betulin (7), and 4-(4-methoxy phenyl)-2-butanone (8) were isolated from the roots of Premna tomentosa. The structures of compounds 1 and 2 were established by detailed spectral analysis using UV, IR, (1)H NMR, (13)C NMR, 1D, 2D and Mass. The newly isolated compounds were screened for rat intestinal α-glucosidase inhibitory and free radical (DPPH) scavenging potentiality. The new icetexane diterpenes (1, 2) and compound 3 were found to have significant α-glucosidase inhibitory and also free radical scavenging (DPPH) activities.