Extraction, phytochemical analysis and in silico antidepressant studies of aqueous extract of leaves of Hibiscus sabdariffa L.

The aim of study is to extract Hibiscus sabdariffa L. leaves, evaluate their phytochemical properties, and
screen in silico antidepressant effects. It is commonly called as roselle belongs to family Mallows or
Malvaceae. This family has more than 200 genera and more than 4000 species. H. sabdariffa leaves are
collected, and extracted by using different solvents, viz., petroleum ether, chloroform, ethyl acetate,
ethanol and water. Extracts obtained are explored for their characteristic features. Among these extracts,
AEHS was selected for further analysis by FTIR, HPLC and GC-MS techniques. Further, four phytoconstituents
from H. sabdariffa, viz., beta-pinene, cyanidin, delphinidin, P-cymene are subjected for in silico
antidepressant evaluation by using MAO-A, 2z5y protein. All the extracts obtained are brown to black in
color and semisolid in nature. % Yield was highest for AEHS (12.4%). Phytochemical analysis showed the
presence of various constituents like alkaloids, glycosides, tannins, flavonoids, anthocyanins, and
phytosterols. AEHS FTIR spectrum showed the functional groups, viz., 1111 cm-1 and 1053 cm-1
corresponding to anthocyanins. HPLC analysis of AEHS also revealed the delphinidin and cyanidin related
peaks with retention time of 22.81 min and 24.97 min, respectively. GC-MS analysis of AEHS showed the
presence of different phytoconstituents. Docking studies reported ligand protein interactions. Betapinene and p-cymene has not showed interaction with amino acids of 2z5y protein. Therefore, these
molecules are reported with weak dock score and low EModel energy. Whereas, cyanidin and delphinidin
showed interaction with GLN (215), MET (445), and TYR (69) amino acids of MAO-A, 2z5y protein
indicating their inhibitory action. Delphinidin with highest EModel energy, shows maximum in silico
antidepressant effect by inhibiting MAO-A, 2z5y protein.