Ph.D. Defence of Ayesha Saleem
CONDUCTION OF PUBLIC DEFENCE IN RESPECT OF AYESHA SALEEM PH. D RESEARCH SCHOLAR, cOLLEGE OF HOME ECONOMICS, UNIVERISTY OF PESHAWAR
Date: 20-05-2026
Time: 10:00 a.m.
Venue: Centre of Biotechnology and Microbiology, University of Peshawar
Research Totpic:
BIOPROSPECTING OF SECONDARY METABOLITES PURIFIED FROM ENDOPHYTIC FUNGI OF ROSMARINUS OFFICINALIS FOR THERAPEUTIC APPLICATIONS
ABSTRACT
In the present study, two endophytic fungal strains Aspergillus candidus and Aspergillus flavus isolated from the medicinal plant Rosmarinus officinalis, were selected for secondary metabolite investigation following initial antibacterial screening. Nutrient media were optimized to enhance fungal growth and metabolite biosynthesis. Among the four media tested, the selected fungi exhibited higher metabolite production in Czapek–yeast broth.
Based on bioactivity profiles, the selected fungal strains were processed for metabolite isolation. Using different chromatographic techniques, one known and four novel metabolites were purified. The known compound 2-hydroxybenzoic acid, was isolated from A. flavus. Three novel compounds, (2E,7E)-6,9-dihydroxy-10-(3-hydroxy-5-oxocyclohexyl)deca-2,7-dien-1-yl acetate; (Z)-5-((4-amino-6-(but-3-en-1-ylcarbamoyl)tetrahydro-2H-thiopyran-2-ylidene)fluoromethyl)- 3,4-dihydro-2H-pyrrole-2-carboxylic acid; and 4-(6-amino-1,7-dihydroxy-7H-cyclopenta [f]isoquinolin-8-yl)-N-(2,6-dihydroxy-3,4-dihydropyridin-3-yl)but-2-yne-1-sulfonamide, were isolated from A. candidus, while one novel compound, 10-amino-6-(dimethylamino)-1,3,8,11- tetrahydroxy-5-methyl-7,12-dioxo-1,4,5,7,8,12-hexahydrotetracene-2-carboxamide, was obtained from A. flavus. Structural elucidation was performed using 1D NMR, 2D NMR, GCMS, and IR techniques.
To evaluate the biological activities of the purified compounds, both in silico and in vitro analyses were conducted. Molecular docking studies of 2-hydroxybenzoic acid with chemical formula C?H?O? and molecular weight 138 amu, revealed strong binding affinity to cyclindependent kinase 2 (CDK2), a key regulator of inflammatory pathways, with a docking score of −6.1 kcal/ mol. Additional docking studies with cyclooxygenase-1 and 2 (COX-1)(COX-2), and high-mobility group protein B1 (HMGB1) yielded scores of −6.0, −5.5, and −4.9 kcal/ mol, respectively, suggesting CDK2 as the primary target for its anti-inflammatory action. Egg albumin denaturation assay was carried out for in vitro anti-inflammatory activity. Although ibuprofen exhibited greater inhibition of protein denaturation than 2-hydroxybenzoic acid alone, their combination showed the highest inhibition rate (29.56% at 300 μg/mL), indicating a synergistic effect.
The compound (2E, 7E)-6,9- dihydroxy-10- (3-hydroxy-5- oxocyclohexyl)deca-2, 7-dien-1-yl acetate, with chemical formula C??H??O? and molecular weight 341 amu, showed strong binding affinity (−7.7 kcal/ mol) to lanosterol 14α-demethylase from Candida albicans, suggesting potential inhibition of ergosterol biosynthesis. In vitro antifungal assays revealed moderate inhibition of C. albicans growth at 500 µg/mL (15.5%) and 1000 µg/mL (24.3%), compared to fluconazole as a standard.
The compound (Z)-5- ((4-amino-6- (but-3-en-1- ylcarbamoyl) tetrahydro-2 H-thiopyran-2- ylidene) fluoromethyl)-3, 4-dihydro-2H-pyrrole- 2-carboxylic acid, with chemical formula C??H??FN?O?S and molecular weight 355 amu, demonstrated promising antimicrobial potential, with docking scores of −7.6 kcal/ mol and −8.2 kcal/ mol against penicillin-binding protein and lanosterol 14α-demethylase, respectively. Antimicrobial efficacy was evaluated using agar tube diffusion and agar well diffusion methods. At 500 µg/mL and 1000 µg/mL, growth inhibition was observed for E. coli (36% and 57%), S. aureus (20% and 25%), and C. albicans (16% and 29%).
The compound 4-(6-amino-1,7-dihydroxy-7H- cyclopenta[f] isoquinolin-8-yl)- N-(2, 6-dihydroxy3, 4-dihydropyridin-3 -yl)but-2- yne-1-sulfonamide, with chemical formula C??H??N?O?S and moleculae weight456.1 amu, exhibited docking scores of −8.8 kcal/ mol and −10.2 kcal/ mol with penicillin-binding protein and lanosterol 14α-demethylase, respectively. In vitro assays showed growth inhibition of E. coli (30% and 47%), S. aureus (18% and 20%), and C. albicans (16.8% and 31%) at 500 µg/mL and 1000 µg/mL.
The compound 10-amino-6- (dimethylamino)-1,3,8,11- tetrahydroxy-5- methyl-7,12- dioxo1,4,5,7,8,12-hexahydrotetracene- 2-carboxamide, with chemical formula C??H??N?O? and moleculae weight 441 amu, showed docking scores of −8.9 kcal/ mol and −9.1 kcal/ mol with penicillin-binding protein and lanosterol 14α-demethylase. In vitro antimicrobial assays revealed inhibition of E. coli (21% and 26.3%), S. aureus (38% and 62.4%), and C. albicans (14.5% and 21.2%) at 500 µg/mL and 1000 µg/mL.Collectively, these findings highlight the potential of endophytic fungi from Rosmarinus officinalis as promising sources of novel bioactive metabolites with antibacterial, antifungal, and anti- inflammatory properties. This study provides a foundation for future drug discovery efforts and highlights the therapeutic potential of fungal secondary metabolites.