Bio-Potency and Molecular Docking Studies of Isolated Compounds from Grewia optiva J.R. Drumm. ex Burret.

In the study, two novel compounds along with two new compounds were isolated from Grewia optiva. The novel compounds have never been reported in any plant source, whereas the new compounds are reported for the first time from the studied plant. The four compounds were characterized as: 5,5,7,7,11,13-hexamethyl-2-(5-methylhexyl)icosahydro-1H-cyclopenta[a]chrysen-9-ol (IX), docosanoic acid (X), methanetriol mano formate (XI) and 2,2'-(1,4-phenylene)bis(3-methylbutanoic acid (XII). The anticholinesterase, antidiabetic, and antioxidant potentials of these compounds were determined using standard protocols. All the isolated compounds exhibited a moderate-to-good degree of activity against acetylcholinesterases (AChE) and butyrylcholinesterase (BChE). However, compound XII was particularly effective with IC50 of 55 µg/mL (against AChE) and 60 µg/mL (against BChE), and this inhibitory activity is supported by in silico docking studies. The same compound was also effective against DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid) radicals with IC50 values of 60 and 62 µg/mL, respectively. The compound also significantly inhibited the activities of α-amylase and α-glucosidase in vitro. The IC50 values for inhibition of the two enzymes were recorded as 90 and 92 µg/mL, respectively. The in vitro potentials of compound XII to treat Alzheimer's disease (in terms of AchE and BChE inhibition), diabetes (in terms of α-amylase and α-glucosidase inhibition), and oxidative stress (in terms of free radical scavenging) suggest further in vivo investigations of the compound for assessing its efficacy, safety profile, and other parameters to proclaim the compound as a potential drug candidate.

Isolation, pharmacological evaluation and molecular docking studies of bioactive compounds from Grewia optiva.

BACKGROUND: Traditionally, Grewia optiva is widely used for the treatment of many diseases like dysentery, fever, typhoid, diarrhea, eczema, smallpox, malaria and cough. METHODS: Shade-dried roots of G. optiva were extracted with methanol. Based on HPLC results, chloroform and ethyl acetate fractions were subjected to silica column isolation and four compounds: glutaric acid (V), 3,5 dihydroxy phenyl acrylic acid (VI), (2,5 dihydroxy phenyl) 3',6',8'-trihydroxyl-4H chromen-4'-one (VII) and hexanedioic acid (VIII) were isolated in pure form. Ellman's assay was used to determine the anticholinesterase potential of isolated compounds while their antioxidant potential was estimated by DPPH and ABTS scavenging assays. RESULTS: Amongst the isolated compounds, VI and VII exhibited excellent percent inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) (83.23±1.11, 82.72±2.20 and 82.11±2.11, 82.23±1.21, respectively, at 1000 µg/mL) with IC50 of 76, 90, 78 and 92 µg/mL, respectively. Highest percent radicals scavenging against DPPH and ABTS (87.41±1.20 and 86.13±2.31) with IC50 of 64 and 65 µg/mL, respectively, were observed for compound VII. Molecular docking studies also supported the binding of compound VI and VII with the target enzyme. The para-hydroxyl group of the phenolic moiety is formed hydrogen bonds with the active site water molecule and the side chain carbonyl and hydroxyl residues of enzyme. CONCLUSION: The isolated compounds inhibited the DPPH and ABTS-free radicals, and AChE and BChE enzymes. It was concluded that these compounds could be used in relieving the oxidative stress and pathological symptoms associated with excessive hydrolysis of acetyl and butyryl choline. The results of the study were supported by docking studies for compounds VI and VII.