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In an attempt to predict the active compounds responsible for various therapeutic actions in the
root of Pycnanthus angolensis as reported by many researchers, this research work focused on
the use of benzene and chloroform as solvents in extraction and computational analyses of the
identified compounds. The root was cut, dried, ground and the powder extracted separately with
benzene and chloroform. The extracts were concentrated. Gas chromatography- mass
spectroscopy (GC-MS) was used to identify various constituents in the extracts. The estimated
HOMO-LUMO energy gap and associated global parameters: global hardness and softness,
chemical potential, electrophilicity, electronegativity, ionization potential, electron affinity and
polarizability of the optimized structures of the identified compounds from the root extracts (four
compounds) were determined by Density Function Theory (DFT) using Becke-3-Lee Yankpar
function (DFT-B3LY 631G*). Tributylactylcitrate (TAC) (10.20 %) and 1-(4-hydroxy-3-
methoxyphenyl) propan-2-one (HMPP) (89.80 %) were obtained from benzene extracts.
Chloroform extract has two major compounds: 4-(2S,3R)-4-(Benzo[d][1,3]dioxol-5-yl)-2,3-
dimethylbutyl)-2-methoxyphenol (BDDBMP) (29.10 %) and 1,5-bis(4-hydroxy-2-
methoxylphenyl)-3-pentanone (BHMPP) (45.51 %) and seven minors: n-Hexadecanoic acid
(1.15 %), tributylactylcitrate (4.68 %), tetratetracontane (0.49 %), Tritetracontane (0.59 %),
Ethyl homovanillate (0.73 %), 2,6 Di-p-tolylpyridine (1.25 %) and Bromodocosane (0.73 %).
The estimated values showed that the HOMO-LUMO energy gaps of all the major compounds
ranges from 11.72 eV (Lowest activity) to 8.80 eV (highest activity). The present research work
has been able to identify four major compounds from the root sample and they all have similar
chemical potentials (-5.86, -4.58, -4.52 and -4.40 eV). This work is the first to determine the
structural-activities relationship of the identified major compounds.
Key Words: Pycnanthus angolensis, Root extract, HOMO-LUMO, Benzene and Chloroform