3. Results
3.1. In vitro lipoxygenase inhibition assay
All compounds showed promising inhibitory activity
against lipoxygenase. IC50 values of Taxusabietane A, Taxusabietane
C and Taxamairin F were 57±0.31. Standard compound
Baicalein and Tenidap sodium showed the IC50 value
being 22.1±0.03 μM and 41.6±0.02 μM.
3.2. Molecular docking simulations
Taxusabietane A showed considerable molecular interactions
with important subsites of LOX catalytic site (Fig. 2).
Keto group of Taxusabietane A at position C-7 seems to play a
vital role in its inhibitory activity through hydrogen bonding
interactions with His523 at distance of 3.06 Å (Fig. 3). This
macromolecular complex was further stabilized by the
favorable hydrophobic interactions (Fig. 4) between the
enzyme and Val769, Leu773, and Ile572. On other side,
methoxy group at position C-12 was held strongly through
hydrogen bonding (2.98 Å) with His518. Phenolic group at
position was found to be interacting with Trp519 via hydrogen
bonding (3.11 Å). Molecular shape of Taxusabietane A fits
well into the binding pocket, thus preventing access of
substrate to catalytic site of LOX. As a whole, Taxusabietane A
seems to be supported by both hydrophilic and hydrophobic
interactions. No electrostatic clash was observed between
LOX and Taxusabietane A.
3.3. Carrageenan-induced oedema
Taxusabietane A significantly (pb0.05) reduced oedema
induced by carrageenan at a dose 5 and 10 mg/kg (Fig. 5).
However standard compound indomethacin (5 mg/kg) showed
comparatively better activity than test compounds.
3.4. Acute toxicity
All the compounds were found safe after 48 h of
administration. Statistically, no considerable difference was
observed between the negative control and other treatment
groups both in terms of mortality and morbidity.