Asma Ejaz

Two New Antioxidant Phenylpropanoids from Lindelofia stylosa

Two new phenylpropanoids were isolated from Lindelofia stylosa (Kar. and Kir.) and characterized as 4‐hydroxy‐N‐{4‐[(E)‐3‐(4‐hydroxy‐3‐methoxyphenyl)prop‐2‐enamido]butyl}benzamide (1) and 2‐[3‐hydroxy‐4‐(4‐hydroxyphenoxy)phenyl]‐1‐(methoxycarbonyl)ethyl (E)‐3‐(3,4‐dihydroxyphenyl)prop‐2‐enoate (2). Four known compounds, i.e. two phenylpropanoids, p‐coumaric acid (=(E)‐3‐(4‐hydroxyphenyl)prop‐2‐enoic acid; 3) and ferulic acid (=(E)‐3‐(4‐hydroxy‐3‐methoxyphenyl)prop‐2‐enoic acid; 4), and two naphthalene glycosides, 8‐O‐β‐D‐glucopyranosyltorachrysone (5) and 8‐O‐β‐D‐glucopyranosyl‐6‐demethoxytorachrysone (6), were also isolated for the first time from the plant. Compounds 1–6 were subjected to various antioxidant assays, including DPPH radical‐ and superoxide anion‐scavenging, and Fe2+‐chelation assays. Compound 2 was found to be most active in all assays with potency nearly similar to that of propyl gallate. Besides 2, compounds 1 and 5 were also found to be active in DPPH radical‐scavenging standard assay.

Xanthine oxidase inhibiting flavonol glycoside from Amberboa ramosa

A new flavonol glycoside (1) has been isolated from the ethyl acetate soluble fraction of Amberboa ramosa and assigned the structure 5,7,4′-trihydroxy-3,8-dimethoxylflavone 5-O-β-D-gluco-pyranoside (1). In addition, 6,4′-dihydroxy-3,5,7-trimethoxyflavone (2), 5,7-dihydroxy-4′-methoxyflavone (3) and (23R)-5α-cycloart-24-ene-3β,21,23-triol (4) have also been reported for the first time from this species. The structures were deduced on the basis of 1D and 2D NMR techniques. The compounds 1–3 displayed weak to moderate inhibition against the xanthine oxidase enzyme.

Synthesis and DPPH scavenging assay of reserpine analogues, computational studies and in silico docking studies in AChE and BChE responsible for Alzheimer's disease

Alzheimers disease (AD) is a fast growing neurodegenerative disorder of the central nervous system and anti-oxidants can be used to help suppress the oxidative stress caused by the free radicals that are responsible for AD. A series of selected synthetic indole derivatives were biologically evaluated to identify potent new antioxidants. Most of the evaluated compounds showed significant to modest antioxidant properties (IC50 value 399.07 140.0±50 µM). Density Functional Theory (DFT) studies were carried out on the compounds and their corresponding free radicals. Differences in the energy of the parent compounds and their corresponding free radicals provided a good justification for the trend found in their IC50 values. In silico, docking of compounds into the proteins acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), which are well known for contributing in AD disease, was also performed to predict anti-AD potential.